A charging station for electric vehicles which have rechargeable batteries is provided. The charging station comprises a power section controlled by a fast acting power controller, a power connector and associated power cables for connecting to the vehicle, an interface with signal cables to carry status and/or control signals between the vehicle and the power controller, and a lockout which precludes delivery of power to the vehicle except when the power connector is in place. High charging currents are delivered to the battery of the vehicle as a consequence of signals at any instant in time to the power controller, so as to be able to turn delivery of the charging current on and off in less than a few milliseconds. The resistance free voltage of the vehicle battery is measured during intervals when the charging current is off, and the operation of the power controller is a function of the battery resistance free voltage at any instant in time. Operation may be manually controlled, whereby at least maximum voltage and current settings are preset by the operator; or operation may be completely automatic and under the control of a charge controller within the vehicle and associated with the battery. Thus, for each vehicle that is equipped with a charge controller, the operation of the charging station is battery specific, and may be quite different as to conditions of voltage and current being delivered to another electric vehicle which may be subsequently re-charged from the same charging station.

While, in general, the present invention is specifically directed to electric vehicles of the sort that are, essentially, passenger vehicles or cargo vehicles such as vans and light trucks, it will be kept in mind that the present invention is equally adapted for use with such other electric vehicles as electric golf carts, fork lift trucks and other industrial trucks and pallet lifters, and the like. However, as discussed in greater detail hereafter, the present invention particularly lends itself to commercial applications wherein electric vehicles such as passenger vehicles and on-road cargo vehicles may recharge their batteries in much the same manner as present day vehicles having internal combustion engines re-fill their fuel tanks. Thus, a charging station for electric vehicles in keeping with the present invention may be found at street corners, along highways, and so on.
There are presently a number of experimental electric vehicles of the passenger type. Almost universally, however, those vehicles are extremely inefficient, carry very heavy batteries, and at best have very limited range of perhaps 100 or 200 km before the batteries need to be recharged. Significant research is being carried on throughout the world to develop new batteries which have much higher power per unit weight, and higher capacity, so as to allow faster and more long-ranging vehicles to be developed; and the present invention recognizes that as such vehicles reach the road either experimentally or particularly as commercial vehicles, there will be a much greater requirement for facilities to recharge them. Of course, such charging stations must be capable of delivering charging power to the batteries safely, quickly, and economically.
It follows that such charging stations must be capable of being controlled in such a manner that different batteries, having different capacities and even different terminal voltages--or, for that matter, being of different types--must be accommodated at the charging station for delivery of charging power. That means that there must be sufficient control either within the charging station or associated with the batteries to be charged, to permit such charging conditions; and as well, the charging station must be equipped in such a manner as to be compatible with the electric vehicles. Obviously, for commercial installations, means must also be provided to measure the amount of power being delivered and to arrive at a monetary charge to be paid by the consumer. The specifics of that issue are beyond the scope of the present invention.
Presently, electric vehicles are often equipped with an on-board charger associated with the battery, whereby slow charging--for example, overnight--of the battery may be accomplished from an ordinary electrical outlet. It may also be that the garage in which the vehicle is stored may be equipped with a stationary charger which may otherwise be the same as an on-board charger, but whereby more than one vehicle may be charged--however, usually only one at a time. These two methods are the ones which are most often found in electric over-the-road vehicles, while the second alternative noted above is most usually found in industrial charging installations for fork lift trucks and the like. Other electric vehicles such as golf carts may have removable battery trays which are taken from the vehicle and charged while a duplicate battery tray is placed in the vehicle to continue its useful working employment. Clearly, for electric passenger vehicles, and the like, the mass and weight of batteries required to power the vehicle--as well as the cost of the batteries--preclude any consideration of removable battery trays.
At present, most electric vehicles--particularly commercial and industrial vehicles such as fork lift trucks, golf carts, and the like--employ lead acid batteries. Other prospective and experimental vehicles, at least in the near future, may employ nickel cadmium, nickel iron, or nickel metal hydride batteries, with other batteries such as liquid sodium being further over the horizon.
The present invention, however, will accommodate all of those circumstances of battery charging for all kinds of electric vehicles, such as those discussed above.
Reference is made to co-pending U.S. patent applications Ser. No. 07/253,703 filed Oct. 6, 1988 and Ser. No. 07/676,523 filed May 2, 1991, for in depth discussions of fast battery charging and discussion of the battery chargers having advanced features whereby very rapid and safe battery charging is assured. Both of those co-pending applications are assigned to a common assignee herewith, with a common inventor as herein. The chargers of those inventions are capable of recharging quality traction or SLI batteries in 10 to 20 minutes. However, the energy requirement of an electrical automobile, in particular, may be in the range of from 20 to 50 kWh, and to deliver that energy in a short time requires that the charger have a high power rating, for example in the range of 100 to 300 kW. Obviously, chargers having power ratings of 300 kW have to be strategically located and properly connected into the electrical distribution grid. Such chargers may be found in charging stations in keeping with the present invention in typical locations such as ordinary service stations, fleet depots, and perhaps even in such locations as parking lots and the like.
However, as noted above, electric vehicles including electric automobiles and delivery vans and the like, are far from standardized as to the battery capacities and voltages that are built into them, and will probably continue in that same mode. For example, an experimental vehicle identified as IMPACT.TM. produced by General Motors has a 320 volt battery with a capacity of 45 Ah; whereas the PANDA ELETTRA.TM. produced by Flat carries a 72 volt battery, but has a capacity of 185 Ah.
What the present invention provides is a universal charging station at which a wide variety of electric vehicles may be charged, over a wide range of parameters. Of course, a number of preconditions apply, including the requirement that the vehicle to be charged must be equipped with a compatible power connector, and the obvious requirement that the charging station must be capable of providing a DC voltage at a sufficient level for any given vehicle, and at high current rates. Because of the nature of the charging station, signals will pass from the battery being charged to a power controller in the power section of the charging station, so at least a minimal accommodation for signals which are at least indicative of the voltage of the battery at any instant in time must be made. Of course, if the entire installation including the power delivery section of the charging station and the control means which controls the power section (and which may be specific as to the battery to be charged) are in keeping with the teachings of the co-pending applications noted above, then assured delivery of the maximum power in the shortest possible time to the battery will be achieved. Otherwise, the charging station of the present invention will still operate, but there will be no certainty as to optimum performance.
To that end, the present invention provides a charging station for electric vehicles that are equipped with a rechargeable battery, a traction motor and a traction controller for said traction motor, where the charging station comprises the following principle components:
A power section; a power controller section; a power connector for connecting the power section to an electric vehicle for recharging the battery thereof; an interface between said charging station and said electric vehicle; power cables capable of carrying high charging currents from the power section through the power connector to the electric vehicle; signal cable means capable of carrying control signals between the power controller section and the electric vehicle; and lockout means.
The power section is capable of delivering high charging currents at the requisite charging voltage for the battery being charged within predetermined limits of power to be delivered. The rate of delivery of the charging current is controllable.
The power section comprises a power source, a rectifier, and a switching inverter module; and each of the power controller section and the inverter module are fast acting so as to be able to turn delivery of the charging current on and off in less than a few milliseconds. More generally, the power section comprises a power source rectifying means, and means for controlling the flow of charging current to the rechargeable battery.
The signal cable carries signals from the battery to the power controller that are at least indicative of the voltage of the battery at any instant in time. At least the power cables and the signal cable means are associated with the interface.
Means are provided for measuring the resistance free voltage of the battery during intervals when delivery of said charging current to said battery has been turned off. Thus, operation of the power controller section may be affected by the resistance free voltage; and thereby operation of the switching inverter module or other means for controlling the flow of charging current to the battery, and of the charging station, may be controlled as a function of the resistance free voltage of said battery.
The lockout means of the charging station is adapted to preclude delivery of charging current to the battery except when the lockout means is locked closed. The lockout means is conveniently associated with said power connector.
Thus, operation of the charging station to recharge a battery in an electric vehicle is contingent upon the lockout means being locked closed so as to assure flow of charging current and control signals on their respective cables, and the charging operation is controlled so that the power being delivered is within the predetermined limits. Of further significance is the safety aspect of the lockout means, whereby the physical and electrical design of the power connector may be such as to assure that the operator will not be able to contact--or be exposed to--high voltage terminals connected to the battery or to the charging station.
In a particular type of charging station in keeping with the present invention, which may be such that the charging station will provide optimum performance, the charging station will be adapted to communicate with an on-board charge controller located within the vehicle, and which is adapted to control the rate of delivery of charging current to the battery. In that case, the charge controller is specific as to the battery to be charged so that its operating functions are contingent upon the type of battery to be charged, its nominal voltage and its nominal electrochemical energy capacity. The charge controller is adapted to pass signals via the signal cable means to the power controller section. Thus, operation of the power controller section is contingent upon the nature of signals received by it from the charge controller, and thereby operation of the charging station is controlled and is battery specific.
In the usual circumstances, the interface and the power connector are physically associated with each other. Indeed, the interface and the power connector may be one and the same thing. Moreover, in the most simple installations where operation of the battery charging station is not battery specific, the signals relating to the resistance free voltage of the battery may be passed over the charging current cables, thereby obviating the neccessity for separate signal cables in such circumstances.


A process is disclosed for producing CF.sub.3 CH.sub.2 F from CF.sub.3 CHClF by catalytic chlorination of CF.sub.3 CHClF to CF.sub.3 CCl.sub.2 F at elevated temperature, and reaction of CF.sub.3 CCl.sub.2 F with H.sub.2 in the presence of a carbon-supported precious metal catalyst at a temperature of from about 100.degree. C. to 250.degree. C. Suitable catalysts for the chlorination include carbon catalysts and catalysts wherein halides of certain metals (La, Zn, Cu, Cr, Ru, Rh, and/or Pt) are supported on carbon.

British Patent Specification 1,225,956 discloses a process for the production of a chlorofluoroethane of the general formula CH.sub.3-n Cl.sub.n CClF.sub.2 where n is 0 to 3 comprising the photochemical chlorination of 1,1-difluoroethane, which may contain less than 2% HF.
There has been considerable interest in processes for the chlorination of aliphatic hydrofluorocarbons and hydrochlorofluorocarbons which avoid using expensive actinic light to effect such chlorination.
U.S. Pat. No. 4,490,534 discloses a process for the preparation of 3-chloro-5-trifluoromethylpyridine derivatives comprising reacting a 5-trifluoromethylpyridine having a hydrogen atom at the 3-position with chlorine in the presence of a catalyst selected from the group consisting of activated carbon and a chloride of a metal selected from the group consisting of iron, antimony, copper and zinc.
2-Chloro-1,1,1,2-tetrafluoroethane (i.e., HCFC-124 or CF.sub.3 CHClF) is a chlorofluoroethane which has been prepared by the addition of HF to halogenated olefins and by the reaction of 2,2-dichloro-1,1,1-trifluoroethane with HF. HCFC-124 can be reacted with hydrogen to form 1,1,1,2-tetrafluoroethane (i.e., HFC-134a or CF.sub.3 CH.sub.2 F) which is a useful refrigerant and propellant.
Other processes have been disclosed for the preparation of HFC-134a which can produce HCFC-124 as a by-product. For example, 2,2-dichloro-1,1,1,2-tetrafluoroethane (i.e., CFC-114a or CCl.sub.2 FCF.sub.3) can be converted to HFC-134a as the major product and HCFC-124 as a minor product, by catalytic hydrogenolysis. The HCFC-124 can be recycled to the hydrogenolysis reactor to produce additional HFC-134a.
A higher temperature is generally required to catalytically hydrogenolyze HCFC-124 to HFC-134a than is required for the hydrogenolysis of CFC-114a to HFC-134a. Consequently, catalyst stability can be affected and unwanted by-products such as 1,1,1-trifluoroethane may increase. There is thus a desire to provide a means to convert HCFC-124 to HFC-134a without subjecting hydrogenolysis catalysts to such higher temperatures.

Catalytic process for producing CF.sub.3 CH.sub.2 F


A highly linear, variable capacitor array constructed from multiple cells. Each cell includes a pair of passive, capacitor components connected in anti-parallel. The capacitor components may be Metal Oxide Semiconductor (MOS) capacitors. A control circuit applies bias voltages to bias voltage terminals associated with each capacitor component, to thereby control the overall capacitance of the array.

1. Technical Field
This patent application relates to capacitors, and in particular to a highly linear, variable capacitor implemented from an array of semiconductor capacitor cells.
2. Background Information
A capacitor is a two-terminal, passive electrical component used to store energy in an electric field. Capacitors may take many different physical forms, but in general will contain at least two electrical conductors separated by a dielectric (insulator). When a potential difference (voltage) applied across the conductors, a static electric field develops across the dielectric, causing positive charge to collect on one conductor and negative charge on the other conductor. Energy is thereby stored in the resulting electrostatic field. A capacitor is most often characterized by a single constant value, the capacitance, which is the ratio of the electric charge on each conductor to the potential difference between them. Other parameters, such as quality factor (Q), frequency response, and/or linearity, are also important in selecting an appropriate capacitor design.
Capacitors are commonly used in many different types of alternating current (AC) circuits, and especially radio frequency (RF) circuits. Capacitors are combined with inductors and other components to implement filters, duplexers, resonators, tuners, and other functions in these circuits. Electronic devices such as smart phones, tablets, laptop computers, and the like are now typically expected to use many different radio communication protocols and operate over a wide variety of frequencies, while at the same time being as small and inexpensive as possible. Resonator design, and hence capacitor design, becomes a critical aspect of achieving these goals.


A method of managing NAND flash memory in an electronic device whereby system performance of the electronic device is minimally impacted is disclosed. The method comprises collecting files that are marked for deletion or truncation; monitoring an activity level of the electronic device; monitoring a total size of the list of files that are marked for deletion or truncation; determining if the electronic device is idle; and trimming the flash memory of the electronic device if predetermined criteria are met.

In order for managed NAND flash memory to work properly, and to provide longevity in the field, the flash controller must be aware of which flash cells are 'in use'. This "in-use" information is used to allow for wear leveling, and other flash maintenance. The traditional method available to keep the controller informed of unused blocks is to implement a TRIM command on each block, i.e. "trimming" the flash memory. Typically, a TRIM command permits an operating system to tell the flash controller which blocks of data are no longer in use, and can be erased and reused. However, implementing a TRIM command immediately upon deletion can have a significant impact on file system performance. Once a file is deleted, most file systems do not provide a low-impact method of determining which blocks are free, although they are able reuse those blocks at a future opportunity due to internal accounting in the file system. However, since the flash controller is not aware of these "unused" blocks, it is unable to use them for flash maintenance.

Delayed trim of managed NAND flash memory in computing devices


A description is given of a process for microencapsulating hydrophobic oils with color reactants of color reaction sytems dissolved therein, a cationized melamine/formaldehyde precondensate being precipitated in ultra-fine suspension from its acid aqueous solution, accompanied by vigorous stirring and by modifying the solubility conditions, said suspension is mixed under vigorous stirring with a hydrophobic oil containing the color reactants in dissolved form, the oil-in-water dispersion obtained is adjusted acid and an aqueous solution of a water-soluble, nonionic melamine/formaldehyde precondensate is added, accompanied by stirring, for forming the microcapsule envelope. For stabilizing the oil-in-water dispersion, the pH-value of the acid, aqueous solution of a cationized melamine/formaldehyde precondensate which, in the weak acid, neutral and alkaline, aqueous use range is present in insoluble, cationizable form, is raised in the absence of water-soluble, organic polymers by the addition of Bronsted bases and accompanied by vigorous stirring to such an extent that the cationizable melamine/formaldehyde precondensate is precipitated in ultra-fine suspension as a result of the modified solubility conditions. The possible elimination of the water-soluble, organic polymers is economically advantageous.

Many different processes are known for the microencapsulation of hydrophobic oils, particularly with colour formers of colour reaction recording systems dissolved therein. The thus obtainable microcapsules, which as a rule contain an oily hydrophobic solution of the colour former (a homogeneous substance) are generally applied in conventional manner to the underside of a sheet of paper, the CB sheet. The latter can be brought into contact with a so-called CF sheet, in which the surface facing the CB sheet is coated with a reactant which is acid for the colour former. The acid reactant can e.g. be an acid-treated clay, such as montmorillonite clay, or also a low molecular weight phenolic resin, such as a phenol formaldehyde novolak resin. If the acid reactant is an acid compound soluble in oily hydrophobic liquids, then it can also be encapsulated. During the printing process, the said capsules are crushed by the printing types. Therefore the reactants come into contact with one another and supply a coloured character on the CF sheet. The two colour reactants can also be applied to the surface of a single sheet, in order to obtain a so-called autogenic system. It is then recommended to encapsulate both reactants, if the acid reactant is soluble in the oil, in order to prevent an undesired premature reaction of the reactants.
For the production of capsule envelopes of microcapsules provided for duplication purposes in colour reaction systems, numerous encapsulation processes are known. They are e.g. based on the use of gelatin coacervate, polyisocyanate, polyamide or aminoplast systems. The aforementioned process is based on an aminoplast system, in which a water-soluble, non-ionic melamine/formaldehyde precondensate is reacted with a water-soluble polymer reactive therewith, accompanied by the formation of the capsule envelope. Increasing significance has been attached to this process of late. It can be relatively easily controlled and takes place under comparatively mild reaction conditions, so that even very sensitive colour formers remain undamaged during the reaction.
German Patent 35 45 803, which corresponds to U.S. patent application Ser. No. 922,591, now U.S. Pat. No. 4,824,823, describes a process of the aforementioned type in detailed form. This process leads to a particularly stable oil-in-water dispersion, in that the aqueous solution of a cationic melamine/formaldehyde precondensate and that of an organic polymer are mixed, accompanied by vigorous stirring, in order to bring about optimum turbulence and the exclusion of disturbing laminar conditions. As a result the originally dissolved, cationized melamine/formaldehyde precondensate is separated in ultra-fine suspension in the presence of a water-soluble polymer. These precipitated ultra-fine suspended particles leads to a particularly favourable stabilization of the oil-in-water dispersion, in which the capsule envelope is formed by condensation reactions with the water-soluble non-ionic melamine/formaldehyde precondensate as the main reactant.
The process described in German Patent 35 45 803 uses a water-soluble polymer in the first process stage, which is believed to interact with the cationic melamine precondensate to induce precipitation of the precondensate in ultra-fine suspension. It is to be assumed that this interaction is based on the presence of suitable and in particular Zerewitinoff-active hydrogen atom-carrying functional groups in the polymer. Such functional groups, which react with the melamine/formaldehyde precondensate, have long been known and in particular include acid amide amino imino ester ether hydroxyl urethane thiol or mercaptan groups. Preferred examples of the water-soluble polymers are polyvinyl alcohol, gelatin and maleic anhydride copolymers, particularly ethylene/maleic anhydride copolymers or styrene/maleic anhydride copolymers. Particular preference is given to acrylamide/acrylic acid copolymers, starch, cellulose derivatives such as carboxymethyl cellulose (CMC) or hydroxyethyl cellulose (HEC), alginates, such as sodium alginate, polyurethanes and polyethylene oxide. The acrylamide/acrylic acid copolymer has proved especially advantageous as a water-soluble organic polymer in this process, but constitutes a significant cost factor in the overall process of German Patent 35 45 803.

Process for microencapsulating hydrophobic oils, the microcapsules obtained and the use thereof


A process for producing a carbon material for an electric double layer capacitor electrode, including activating a graphitizable carbon or a graphitizable carbon source to have its pore volume in the range of 0.6 to 1.5 cm3/g, and imparting mechanical impact force to the graphitizable carbon or the graphitizable carbon source activated in the activating step to reduce the pore volume to at most 75% of that before the mechanical impact force is imparted.

1. Field of the Invention
The present invention relates to a process for producing a carbon material useful for an electrode for e.g. an electric double layer capacitor, a process for producing an electric double layer capacitor electrode and a process for producing an electric double layer capacitor. The electric double layer capacitor of the present invention can be widely used for power sources for portable apparatus, standby power sources for domestic electrical equipment, UPS for optical communication, power sources for electric automobiles and the like.
2. Discussion of Background
As an electric double layer capacitor, a coin type obtained in such a manner that an element having a pair of electrodes consisting mainly of activated carbon and formed on a current collector and a separator sandwiched therebetween, together with an electrolytic solution, is sealed in a metal casing by means of a metal lid and a gasket insulating the casing from the lid, and a wound type obtained in such a manner that a pair of sheet electrodes is wound by means of a separator interposed therebetween to obtain a wound element, which is accommodated in a metal casing together with an electrolytic solution, and sealed in the casing so that the electrolytic solution does not evaporate from an opening of the casing, have been known.
Further, for an application which requires a large current and a large capacitance, a stack type electric double layer capacitor having an element obtained by stacking a large number of sheet electrodes by means of a separator interposed therebetween, incorporated therein, has been proposed (JP-A-4-154106, JP-A-3-203311, JP-A-4-286108). Namely, a plurality of sheet electrodes formed into a rectangle as positive electrodes and negative electrodes, are alternately stacked one on another by means of a separator interposed therebetween to obtain a stacked element, a positive electrode lead material and a negative electrode lead material are connected with the respective terminals of the positive electrodes and the negative electrodes by caulking, and the element in such a state is accommodated in a casing, impregnated with an electrolytic solution and sealed with a lid.
Conventionally, an electrode constituting an electric double layer capacitor has been one made mainly of activated carbon having a large specific surface area, and as the electrolytic solution, a solvent having a high dielectric constant such as water or propylene carbonate has been used so as to dissolve an electrolyte at a high concentration.
In such an electrode made mainly of activated carbon, the charge of an electric double layer formed on the surface of the activated carbon itself contributes to the capacitance of the electric double layer capacitor, and thus activated carbon having a large specific surface area has been employed.
Activated carbon is produced usually by carbonizing and activating a carbon source derived from a plant such as sawdust or coconut shell, a carbon source derived from a coal/petroleum material such as coke or pitch, or a synthetic high polymer carbon source such as a phenolic resin, a furfuryl alcohol resin or a vinyl chloride resin.
The carbonization is carried out usually by heating a carbon source in a non-oxidizing atmosphere at a temperature of from 300xc2x0 C. to 2,000xc2x0 C. The activation is carried out by heating the carbonized product thus obtained in a weak oxidizing gas containing carbon dioxide or water vapor to a temperature of from 500xc2x0 C. to 1,100xc2x0 C., so as to oxidize and exhaust the carbonized product to being it to have a porous structure and to increase its surface area. Otherwise, the carbonized product is mixed with an alkali metal hydroxide (such as KOH) in an amount of several times the mass of the carbonized product, and then the mixture is heated at a temperature of from the melting point of said metal hydroxide to 1,000xc2x0 C. in an inert atmosphere for from several tens minutes to 5 hours so as to increase the surface area. Since the alkali metal hydroxide may cause deterioration in durability of an electric double layer capacitor, it is removed by adequate washing after the activation. Here, in the present specification, xe2x80x9cfrom A to B (A and B are numerical values)xe2x80x9d means at least A and at most B.
As important performances required for an electric double layer capacitor, a) a large capacitance, b) a high energy density, c) a high durability when charging and discharging cycles are repeated, and d) a low internal resistance, may, for example, be mentioned. Among these properties required, as an electrode material presenting a large capacitance, activated carbon obtained by activating a carbon material derived from pitch by heating in the coexistence of an alkali metal hydroxide (alkali activation) or activated carbon obtained by activating a carbon material derived from coke by an alkali has been reported (JP-A-5-258996, JP-A-10-199767, JP-A-63-78513, JP-A-10-199767, JP-A-11-31637). Particularly, it is reported that activated carbon obtained by alkali activation of a carbon material having a relatively developed crystallinity, such as pitch showing optical anisotropy i.e. so-called mesophase pitch as a carbon source, has a large capacitance per mass, and has a relatively high bulk density, and accordingly, when the activated carbon is formed into an electrode, said electrode has a high density, whereby an electric double layer capacitor having a large capacitance per unit volume can be obtained (JP-A-2-185008, JP-A-10-121336).
Further, activated carbon obtained by water vapor activation or alkali activation of a carbon material having a relatively low crystallinity, such as a thermosetting resin such as a phenol resin or pitch showing optical isotropy, as a carbon source, to bring the specific surface area to be high, has a large capacitance per unit mass, and has a high durability when charging and discharging are repeated for a long period of time. However, as the bulk density of the activated carbon is low, the capacitance per unit volume tends to be small.
In general, it tends to be difficult to increase the specific surface area of a carbon material having a developed crystallinity by activation by an oxidizing gas such as water vapor (gas activation), and accordingly activation by using a chemical (chemical activation) is employed to increase the surface area. Particularly, an alkali activation employing an alkali metal hydroxide as a chemical is frequently employed. Although the mechanism of the activation by an alkali metal hydroxide is not clearly understood in detail for the most part, it is considered that, in a case of an activation by KOH for example, KOH infiltrates into between carbon layers at a relatively low temperature of from 400 to 500xc2x0 C., and during this step, carbonation of carbon and gasification of carbon with generated water or carbonic acid gas takes place, whereby carbon is consumed to increase the specific surface area, and metal potassium generated by reduction of KOH is intercalated into between carbon layers to weaken the bonding force between carbon layers (New Edition Activated Carbon, Yuzo Sanada, Kodansha Ltd. Publishers, Scientific). It is considered that in such an activated carbon subjected to alkali activation, bonding force between carbon layers becomes weak as mentioned above, and accordingly when it is used as an electrode for an electric double layer capacitor, not only ions are adsorbed into pores in the activated carbon but a part of ions is adsorbed into pores to widen the space between carbon layers at the time of charging, to present the capacitance.
When the above-mentioned known activated carbon is used for an electrode for an electric double layer capacitor, the capacitance per unit mass of the electrode will be relatively large, but the bulk density tends to be low since the pore volume of the activated carbon is large, whereby when an electrode is prepared by using this activated carbon, it tends to be difficult to fill an adequate mass of activated carbon per unit volume of the electrode, and no electrode having an adequately large capacitance per volume is obtained. Further, in the case of the activated carbon obtained by alkali activation, as easily estimated from the mechanism of the activation, it is very difficult to remove the alkali metal element by washing since it is deeply dispersed and infiltrated into the skeleton of the carbon material. According to the studies by the present inventors, the durability of a capacitor tends to be poor if a large amount of an alkali metal is remaining in an activated carbon electrode.
Under these circumstances, the present invention has been made to overcome the above problems of prior art, and it is an object of the present invention to provide a process for producing a carbon material having a large capacitance per unit volume and a process for producing an electric double layer capacitor having a large capacitance and a high durability using said carbon material as an electrode material.
According to the present invention, a process for producing a carbon material for an electric double layer capacitor electrode, a process for producing an electric double layer capacitor electrode and a process for producing an electric double layer capacitor are provided.
According to the present invention, there is provided a process for producing a carbon material for an electric double layer capacitor electrode, which comprises:
1) a step of activating a graphitizable carbon or a graphitizable carbon source to bring its pore volume to be from 0.6 to 1.5 cm3/g; and
2) a step of imparting mechanical impact force to the graphitizable carbon or the graphitizable carbon source activated in the above step 1) to reduce the pore volume to at most 75% of that before the mechanical impact force is imparted.
Further, according to the present invention, there is provided a process for producing a carbon material for an electric double layer capacitor electrode, which comprises:
1) a step of activating a graphitizable carbon or a graphitizable carbon source to bring its pore volume to be from 0.6 to 1.5 cm3/g; and
2) a step of imparting mechanical impact force to the graphitizable carbon or the graphitizable carbon source activated in the above step 1) to reduce the pore volume to at least 0.1 cm3/g and less than 0.6 cm3/g.
Further, according to the present invention, there is provided a process for producing an electric double layer capacitor electrode, which comprises forming a carbon material obtained by the above process and a binder into the electrode.
Further, according to the present invention, there is provided a process for producing an electric double layer capacitor comprising the electric double layer capacitor electrode obtained by the above process.
As mentioned previously, with respect to an existing electrode material for an electric double layer capacitor represented by activated carbon, an adequate capacitance per mass can be obtained basically when the specific surface area is large, but activated carbon having a large specific surface area usually has a large pore volume, whereby the mass of activated carbon to be filled per unit volume tends to decrease, and accordingly the capacitance per volume will not increase so much. The present inventors have conducted studies to impart mechanical impact force to such an existing activated carbon by a planetary mill to reduce the pores so that the bulk density of an electrode employing said activated carbon is increased and the capacitance per volume is thereby increased. However, the capacitance per mass of such a conventional activated carbon decreases along with decrease in the pore volume, and no electrode having a large capacitance per volume can be obtained, although the density of the electrode employing this activated carbon can be increased.
The present invention has been accomplished on the basis of such discoveries that, with respect to a graphitizable carbon material having a relatively large pore volume, obtained by activation particularly by alkali activation, the capacitance per mass does not significantly decrease even when the pore volume is reduced by imparting mechanical impact force, and accordingly the bulk density of an electrode consisting mainly of this carbon material can be increased while maintaining a large capacitance per mass.
The carbon material obtained by the process of the present invention has a large capacitance per mass and a relatively small pore volume as compared with a conventional activated carbon, and accordingly the electrode density can be increased and the capacitance per volume can be increased resultingly.
According to the present invention, the carbon material for an electric double layer capacitor electrode can be produced by
1) a step of activating a graphitizable carbon or a graphitizable carbon source to bring its pore volume to be from 0.6 to 1.5 cm3/g; and
2) a step of imparting mechanical impact force to the graphitizable carbon or the graphitizable carbon source activated in the above step 1) to reduce the pore volume to at most 75% of that before the mechanical impact force is imparted.
Otherwise, according to the present invention, the carbon material for an electric double layer capacitor electrode can be produced by
1xe2x80x2) a step of activating a graphitizable carbon or a graphitizable carbon source to bring its pore volume to be from 0.6 to 1.5 cm3/g; and
2xe2x80x2) a step of imparting mechanical impact force to the graphitizable carbon or the graphitizable carbon source activated in the above step 1) to reduce the pore volume to at least 0.1 cm3/g and less than 0.6 cm3/g.
The carbon material obtained by the process of the present invention is characterized by that it has a pore volume of preferably at least 0.1 cm3/g and less than 0.6 cm3/g, more preferably at least 0.2 cm3/g and less than 0.6 cm3/g, and has a pore volume smaller than that of a conventional carbon material to be used for an electric double layer capacitor electrode, so as to obtain a high electrode density. If the pore volume is smaller than the above range, the capacitance per mass tends to decrease, and if it is larger than the above range, the electrode density will not be increased.
Further, the carbon material obtained by the process of the present invention has a mean particle diameter of preferably from 2 to 20 xcexcm, more preferably from 3 to 10 xcexcm. If the mean particle diameter is smaller than the above range, the density of the electrode tends to be too high, and the mobility of an electrolytic solution in the inside of the electrode layers tends to decrease, whereby the internal resistance of the capacitor tends to increase, and further, an impalpable powder of less than 1 xcexcm tends to increase, and accordingly the impalpable powder is likely to drop from the electrode, and the leakage current tends to increase. If the mean particle diameter is larger than the above range, particles of the carbon material are likely to aggregate one another in the inside of the electrode layers to form a large space in the electrode layers, whereby the electrode density is less likely to increase.
The carbon material to be used as a material in the present invention is preferably a graphitizable carbon. Carbon materials are roughly classified into a graphitizable carbon which will have a graphite structure when heated to a high temperature of a level of 3,000xc2x0 C. and a hardly graphitizable carbon which will not have a complete graphite structure. Among these two types of carbon materials, it is preferred to use a graphitizable carbon in the present invention, since the capacitance per mass of the hardly graphitizable carbon significantly decreases after the treatment carried out in the process of the present invention to reduce the pore volume by imparting mechanical impact force, whereas the capacitance per mass of the graphitizable carbon does not significantly decrease after the treatment to reduce the pore volume.
As a graphitizable carbon source which forms such a graphitizable carbon by heating at a high temperature, a common thermoplastic resin such as a vinyl chloride type resin, polyacrylonitrile, a butyral resin, a polyacetal resin, a polyethylene resin, a polycarbonate resin or a polyvinyl acetate resin may, for example, be mentioned. By heating such a carbon source at from 500 to 1,100xc2x0 C., a graphitizable carbon can be obtained. Further, a pitch type material such as a petroleum type pitch or a coal type pitch or coke obtained by subjecting such a pitch to a heat treatment may also be mentioned as a preferred graphitizable carbon source in the present invention. A coke is preferred in view of a low cost and a stable supply in the market. A petroleum coke or a coal pitch coke has a relatively small amount of a volatile component at a level of from several percent to several tens percent and has considerably been carbonized, and thus it can be subjected to an activation treatment as it is. However, it is preferred to further heat such a coke in a non-oxidizing atmosphere to bring the volatile component to be from 1 to 5 mass % and to activate the carbonized product thus obtained, whereby a carbon material which has a large capacitance and of which the capacitance is less likely to decrease even when subjected to a treatment to reduce the pore volume after the activation, will be obtained. Here, in the present specification, xe2x80x9cmass %xe2x80x9d means mass ratio in percentage.
In the present invention, the graphitizable carbon obtained by carbonizing the above graphitizable carbon source or a graphitizable carbon source having a small amount of a volatile component is activated as it is. As the activation, a common activation method may be applicable, but preferred is a chemical activation of subjecting the carbon material and a chemical to a heat treatment, particularly preferred is alkali activation using an alkali metal compound as the chemical. In the case of the alkali activation, as the alkali metal compound, an alkali carbonate such as potassium carbonate or sodium carbonate may be used, but it is preferred to use at least one type of an alkali metal hydroxide such as potassium hydroxide, sodium hydroxide, lithium hydroxide, rubidium hydroxide or cesium hydroxide, and particularly preferred is potassium hydroxide.
Such an alkali metal compound is added and mixed in an amount of from 0.2 to 5.0 times the mass of the carbon or carbon source as the material, followed by heating at a temperature of the melting point of the alkali metal hydroxide or above, preferably from 300 to 1,000xc2x0 C., more preferably from 500 to 900xc2x0 C., for from 30 minutes to 10 hours in a non-oxidizing atmosphere. The alkali metal compound decomposes at the above temperature, and the resulting alkali metal strongly erodes the carbon material to weaken the bonding force between layers of the crystals of the carbon material, and at the same time, a complexly developed porous structure is formed in the carbon material, whereby the pore volume will increase. In the present invention, the pore volume is brought to be from 0.6 to 1.5 cm3/g by suitably changing the temperature, the time or the mixture ratio of the alkali metal compound to the carbon material during activation.
If the pore volume of the carbon material is smaller than the above range after completion of the activation, adsorption of electrolytic ions hardly takes place when a capacitor is constituted, whereby the capacitance tends to decrease. Further, if the pore volume is larger than the above range, although the capacitance tends to increase, the electrically conducting path in the carbon material will be cut off, whereby the internal resistance tends to increase when a capacitor is constituted.
Here, the activation in the present invention means a treatment to increase the pore volume by applying a treatment to the carbon material, and it is not limited to the method as disclosed in the present specification so long as the pore volume can be increased.
The alkali metal in the carbon material after the alkali activation is washed off with water or neutralized by e.g. an acid, and the carbon material is washed with water and adequately dried.
The carbon material obtained by the process of the present invention contains an alkali metal as an impurity in an amount of preferably at most 2,000 ppm, more preferably at most 1,500 ppm, furthermore preferably at most 500 ppm. A part of the alkali metal contained in the carbon material obtained by the process of the present invention is originally contained in the material as the carbon source, but most of it is incorporated in the carbon material when the carbon material and the alkali metal compound are mixed and subjected to a heat treatment. Most of the alkali metal incorporated in the carbon material can be removed by the following washing treatment, but if the washing treatment is inadequate, the residual amount of the alkali metal exceeds 2,000 ppm, which may cause deterioration in durability due to reaction of the alkali metal with an electrolytic solution when a capacitor cell is constituted.
Further, of the carbon material obtained by the process of the present invention, the amount of functional groups on the surface is preferably from 0.1 to 0.5 meq./g, more preferably from 0.2 to 0.4 meq./g. If the amount of functional groups on the surface is larger than the above range, the capacitance tends to increase, but the cell internal pressure tends to significantly increase due to generation of gas when a capacitor cell is constituted, whereby a long term durability may be impaired. If the amount of functional groups on the surface is smaller than the above range, the capacitance may decrease.
With respect to the carbon material obtained by the process of the present invention, the amount of functional groups on the surface increases during the treatment to reduce the pore volume by imparting mechanical impact force, which may deteriorate durability of the capacitor cell, and accordingly it is very important to control the amount of functional groups on the surface. In the present invention, the amount of functional groups on the surface of the carbon material is controlled preferably by carrying out a heat treatment under vacuum or in an inert atmosphere of e.g. nitrogen gas at a temperature of at least 300xc2x0 C. and less than 750xc2x0 C. for from 10 minutes to 10 hours, after the treatment to reduce the pore volume is carried out by imparting mechanical impact force to the carbon material.
It is preferred to control the amount of functional groups on the surface of the carbon material obtained by the process of the present invention from the above reasons, but the amount of functional groups on the surface may be within the above preferred range as it is in some cases depending upon the type of the carbon material or the conditions of the heat treatment with the alkali metal compound, and it is not necessary to apply a heat treatment in such a case. Here, the fact that the durability of a capacitor cell tends to be poor when the amount of functional groups on the surface is large has already been reported (Denki Kagaku (Electrochemistry) vol 59, No. 7, 1991, p607-613).
As reasons why it is preferred to provide such a lower limit of the amount of functional groups on the surface of the carbon material of the present invention, the following may be mentioned. Namely, it is considered that by mixing the alkali metal compound and the carbon material, followed by heat treatment, the alkali metal is dispersed into between layers of micro graphite crystals in the carbon material to weaken the bonding force between layers and to newly form a surface to be the site to present the capacitance of an electric double layer capacitor. In the present invention, the amount of functional groups on the surface is decreased preferably by applying a heat treatment to the carbon material after the activation, washing and the treatment to reduce the pore volume are completed. However, if the heat treatment temperature is raised, the surfaces newly formed as mentioned above are strongly bonded each other again to excessively reduce the site to present capacitance of an electric double layer capacitor. Accordingly, although the amount of functional groups on the surface is reduced, the capacitance tends to decrease. Further, the pore volume of the carbon material slightly decreases during such a heat treatment in some cases, but there will be no problem when used for a capacitor electrode so long as the pore volume is from 0.6 to 1.5 cm3/g as measured after the heat treatment.
In the process for producing the carbon material of the present invention, mechanical impact force is imparted to the carbon material after the activation and washing are completed, to reduce the pore volume to at most 75%, preferably at most 60%, of that before the mechanical impact force is imparted, or to the absolute value after the treatment to reduce the pore volume of at least 0.1 cm3/g and less than 0.6 cm3/g. The carbon material after the activation has a large capacitance per mass, but has a large pore volume, and accordingly when said carbon material is mixed with a binder and formed into a sheet to obtain an electrode, its bulk density can be brought to be less than 0.6 g/cm3 at highest. Accordingly, since the capacitance per volume can not be increased, the pore volume has to be reduced so as to increase the electrode density. If the pore volume after the treatment to reduce the pore volume is larger than 75% of that before mechanical impact force is imparted, or if the absolute value of the pore volume after the treatment to reduce the pore volume is larger than 0.6 cm3/g, an effect to increase the electrode density tends to be small. Further, if the absolute value of the pore volume after the treatment to reduce the pore volume is smaller than 0.1 cm3/g, although the electrode density may be high, the capacitance per mass of the carbon material will significantly decrease, whereby the capacitance per volume of the electrode decreases on the contrary.
Here, the treatment to reduce the pore volume is, specifically, a treatment of imparting mechanical impact force to the porous carbon material formed in the activation step to break a part of pores to convert the carbon material into a less bulky carbon material. In this step, micropores having a diameter of at most 1 nm, in which common organic electrolyte (such as quaternary ammonium salt) ions are hardly adsorbed, and which is considered to make substantially no contribution to development of the capacitance, are broken by priority.
As a means of imparting mechanical impact force, various ones may be considered, and it is possible to use, for example, a Dodge crusher, a double-roll crusher, an edge runner, a jaw crusher, a cone crusher, a hammer mill, a rotary crusher, a desk crusher, a rod mill, a ball mill, a vibration mill, a planetary mill, a tube mill, a roller mill, an attrition mill, a jet mill, a micron mill or a micromizer. However, the principal purpose of this step is not to reduce the particle diameters of the carbon material, but to break the pores to reduce the pore volume. Accordingly, an apparatus capable of imparting as strong impact force as possible to the powder is preferred. Namely, it is preferred that an impact force exceeding 1 G, preferably exceeding 1.5 G, is imparted, where the unit of the impact force is represented by the acceleration of gravity G, and a preferred apparatus may, for example, be a planetary mill, a vibration mill or an attrition mill. The impact force is preferably at most 20 G, whereby the apparatus will not be under the overload. In a case of a grinder using a grinding medium, it is preferred to use a medium having a large specific gravity so that the impact force is as strong as possible. As a suitable medium, zirconia, alumina, tungsten carbide or steel may, for example, be mentioned. However, materials of inner surface of the grinder and the grinding medium tend to be mixed in the carbon material as impurities during the treatment, and accordingly they are more preferably made of materials which are electrochemically stable when a capacitor cell is constituted. As an electrochemically stable material, an oxide type ceramic may be mentioned. The medium may have any of e.g. spherical, rods and polyhedral shapes, but preferably it is spherical balls, since the application efficiency of the impact energy tends to be high and the medium material is less likely to be mixed in the carbon material.
The treatment to reduce the pore volume may be carried out by using an apparatus with an acceleration of gravity of at most 1 G when mechanical impact force is imparted (such as a rotary ball mill), but the treatment time tends to be long since the impact energy is small. Further, the carbon material tends to be excessively fine (ground) before the pore volume is not so reduced, and the particle diameters suitable for forming an electrode may not be obtained, and accordingly such an apparatus has many demerits as compared with an apparatus capable of imparting a strong mechanical impact force such as a vibration mill, a planetary mill or an attrition mill.
The treatment to reduce the pore volume may basically be carried out either by a dry method or by a wet method of carrying out a treatment in a state of a slurry obtained by mixing the carbon material with a solvent such as water or ethanol. However, a dry method is more preferred since in a wet method, the particle diameters tend to be small before the pore volume will not reduce, and the solvent has to be reduced after the completion of the treatment, whereby the process tends to be complicated. In a case of carrying out the treatment by a dry method, the fluidity of the powder may be extremely high depending upon the properties of the carbon material. In such a case, in the moment that the grinding medium particles collide with the carbon material to impart an impact force, the carbon material is pushed out from the gap in the medium particles, and the medium particles are likely to directly collide with one another, whereby the efficiency in reduction of pore volume tends to decrease, and contamination of the carbon material due to separation of fine powder from the medium tends to be significant in some cases. In such a case, it is preferred to add a treatment assistant in an amount of at most 20 mass %, preferably at most 10 mass %, based on the mass of the carbon material. As the treatment assistant, water, an organic solvent such as an alcohol or a lubricant such as a stearate may be mentioned. By adding a small amount of such an assistant, the fluidity of the carbon material powder tends to be slightly poor and the powder tends to attach to the treatment medium (such as grinding balls), and accordingly the impact force at the time of collision of the medium particles is likely to be transmitted to the carbon material with a high efficiency, and the contamination from the medium tends to decrease.
The time required for the treatment to reduce the pore volume varies depending upon e.g. the type of the treatment apparatus, the specific gravity of the medium or the charge ratio of the medium to the carbon material, and can not necessarily be determined, but the treatment is preferably completed within 24 hours, particularly within 12 hours, to prevent the particle diameters of the carbon material from being excessively small. Accordingly, it is preferred to impart as high acceleration of gravity as possible to the best of the apparatus""s ability.
The treatment by a dry method may be carried out in the air, but it is preferably carried out in an inert atmosphere of e.g. nitrogen gas or argon, since functional groups may be formed on the surface newly formed by grinding of the carbon material.
The pore volume of the carbon material of the present invention is a value measured by Autosorb-1 manufactured by Quantachrome or an apparatus having similar functions, as follows.
The pore volume is represented by a volume of liquid nitrogen obtained in such a manner that nitrogen gas is adsorbed in a sample preliminarily dried under vacuum at 200xc2x0 C. for at least 12 hours, at a temperature of liquid nitrogen to obtain an adsorption isotherm, from which the amount of nitrogen gas absorbed at a relative pressure of 0.995 is obtained and calculated as the volume of liquid nitrogen.
The particle diameter of the carbon material in the present invention is obtained in such a manner that about 0.1 g of a powder of the carbon material is charged into 50 cm3 of ethanol firstly, followed by irradiation with an ultrasonic wave at a frequency of 43 KHz with an output of 45 W for at least 10 minutes, then measurement by a laser scattering method (by using Microtrack Model 2 granulometer, manufactured by Leed and northrup) is carried out, and the result is represented by the particle diameter at the accumulated volume of 50% (D50).
The amount of functional groups on the surface of the carbon material obtained by the present invention is measured as follows.
(1) A 0.5 mol/l NaOH aqueous solution is prepared, which is subjected to neutralization titration with a 0.1 mol/l HCl aqueous solution to obtain a factor.
(2) To the above NaOH aqueous solution, 1 g of a carbon material dried under vacuum at 150xc2x0 C. for at least 5 hours is added, followed by shaking at 20xc2x0 C. for 24 hours.
(3) The carbon material is collected by filtration from the above shaked liquid, and the filtrate is subjected to neutralization titration with the above 0.1 mol/l HCl aqueous solution used in step (1) to obtain a factor.
(4) From the difference between the factors obtained in step (1) and (3), the amount of functional groups on the surface of the carbon material is calculated. The calculation method is disclosed in Journal of Carbon (vol 32, No. 5, p759-769, 1994).
The amount of the alkali metal contained in the carbon material obtained by the process of the present invention is analyzed by the following means. Firstly, the carbon material is put in a high pressure container of a microwave sample decomposition apparatus, nitric acid is added thereto, followed by irradiation with a microwave with a low output, and the inside of the container is made to be in high temperature and high pressure conditions so that the carbon material undergoes oxidative destruction, and this operation is repeatedly carried out several times, then a microwave output is gradually increased while successively adding sulfuric acid and perchloric acid to completely decompose the carbon material. It is confirmed that the carbon material is completely decomposed and no residue is present, then the liquid after decomposition is determined by ICP emission spectrometry.
According to the present invention, an electrode for an electric double layer capacitor can also be provided, which contains the carbon material obtained by the above-mentioned production process and a binder, which may further contain an electrical conductivity-imparting material as the case requires, and which has a bulk density of preferably from 0.6 to 1.0 g/cm3. The reason why the bulk density of the electrode is within the above range is that no adequate capacitance per volume tends to be obtained if the bulk density is lower than 0.6 g/cm3, and if the bulk density is higher than 1.0 g/cm3, the resistance of a capacitor cell tends to be high, although the capacitance per volume tends to increase.
The carbon material produced by the production process of the present invention has a small pore volume and a low bulk density as mentioned above, and accordingly when it is used for forming an electrode, an electrode having a high bulk density and thereby having a large capacitance per volume can be formed.
The electrode for an electric double layer capacitor of the present invention comprises, more specifically, the above carbon material and a binder, and an electrical conductivity-imparting material as the case requires. This electrode is formed, for example, in such a manner that a powder of the carbon material of the present invention and a binder such as polytetrafluoroethylene and preferably an electrically conductive material are adequately kneaded in the presence of a solvent such as an alcohol, molded into a plate by e.g. extrusion molding and further formed into a thin sheet by e.g. rolling. After the solvent is dried, the sheet electrode thus obtained is bonded to a current collector by means of e.g. an electrically conductive adhesive to constitute an electrode assembly. Otherwise, a powder of the carbon material and a binder and an electrically conductive material as the case requires may be mixed with a solvent to obtain a slurry, which is then coated on a current collector metal foil, followed by drying to obtain an electrode incorporated with the current collector.
As the binder, in addition to the above polytetrafluoroethylene, polyvinylidene fluoride, a fluoroolefin/vinyl ether copolymerized crosslinked polymer, carboxymethyl cellulose, polyvinyl pyrrolidone, polyvinyl alcohol or polyacrylic acid may, for example, be used, and among them, polytetrafluoroethylene is particularly preferred as the binder in a case where an electrode is in a form of a sheet. Polytetrafluoroethylene is formed into fibers due to stress imparted to the mixture during the kneading, extrusion molding and rolling steps, and these fibers form a three-dimensional network structure to fix the carbon material and the electrical conductivity-imparting material to minimize separation of fine carbon material particles from the electrode sheet, which causes microshort-circuiting when a capacitor is constituted. Further, different from another binder which combines the carbon material or the electrical conductivity-imparting material in a form of a thin film, polytetrafluoroethylene in a state of fibers combines particles of the carbon material or the electrical conductivity-imparting material, whereby the surface of the particles of the carbon material is less likely to be blocked by the binder, and the whole surface can be utilized as the site for presenting the capacitance. As the polytetrafluoroethylene, preferred is one having a molecular weight of at least 1,000,000 is preferred since it is likely to be formed into fibers.
The content of the binder in the electrode is preferably from about 0.5 to about 20 mass % based on the total amount of the activated carbon and the binder. If the content of the binder is less than 0.5 mass %, the strength of the electrode tends to be inadequate, and if it exceeds 20 mass %, the electrical resistance tends to increase and the capacitance tends to decrease. The amount of the binder incorporated is more preferably from 0.5 to 10 mass %, from the viewpoint of the balance between the capacitance and the strength of the electrode. Here, as a crosslinking agent for the crosslinked polymer, an amine, a polyamine, a polyisocyanate, a bisphenol or a peroxide is preferred.
The carbon material obtained by the process of the present invention is a graphitizable carbon, in which fine crystals of graphite are relatively developed, whereby the electrical resistance of the carbon itself is low, and it is not necessarily required to add an electrical conductivity-imparting material. However, in a case where the internal resistance of a capacitor is required to be extremely low, such as a case of a capacitor for large current discharging, it is preferred to add an electrical conductivity-imparting material to reduce the internal resistance of the electrode. As the electrical conductivity-imparting material, a powder of e.g. carbon black, natural graphite, artificial graphite, titanium oxide or ruthenium oxide may be used. Among them, ketjen black or acetylene black as one type of carbon black is preferably used since the effect to improve electrical conductivity is significant with a small amount.
In a case where the electrical conductivity-imparting material is added, the amount is preferably at least 1 mass %, particularly preferably at least 5 mass %, based on the total amount of the carbon material particles and the electrical conductivity-imparting material. If the amount is too small, the effect to reduce the resistance of the electrode tends to be small, and if the amount is too large, the proportion of the carbon material incorporated will decrease relatively, whereby the capacitance of the electrode will decrease, and accordingly, the incorporated amount is preferably at most 30 mass %, particularly preferably at most 15 mass %.
The solvent for forming a slurry is preferably one capable of dissolving the above binder, and e.g. N-methylpyrrolidone, dimethylformamide, toluene, xylene isophorone, methyl ethyl ketone, ethyl acetate, methyl acetate, ethyl acetate, dimethyl phthalate, methanol, ethanol, isopropanol, butanol or water may optionally be selected.
According to the present invention, an electric double layer capacitor comprising the above electrode having an increased capacitance per volume is further provided. The electrode comprising a carbon material and a binder, or the electrode comprising a carbon material, an electrical conductivity-imparting material and a binder, is incorporated with a current collector, and a pair of the electrodes is disposed so that the electrodes face each other by means of a separator interposed therebetween, and is impregnated with an electrolytic solution to form a base unit of a capacitor.
The current collector to be incorporated with the electrode may be any current collector so long as it has electrochemical and chemical corrosion resistance. As the current collector for the electrode consisting mainly of the carbon material, stainless steel, aluminum, titanium, tantalum or nickel may, for example, be used. Among them, stainless steel and aluminum are preferred from the viewpoint of both performance and price.
The current collector may be in a form of a foil, may be a foam metal of nickel or aluminum having a three-dimensional structure, or may be a net or a wool of stainless steel.
As the electrolytic solution to be used for an electric double layer capacitor of the present invention, a known aqueous or organic electrolytic solution may be used, but preferred is an organic electrolytic solution since the amount of energy accumulated per unit volume tends to increase. The decomposition voltage of an organic electrolytic solution is at least twice that of an aqueous electrolytic solution, and accordingly it is favorable to use an organic electrolytic solution from the viewpoint of the energy density, which is proportional to half of the product of the capacitance and the square of the voltage.
As the organic solvent, it is preferred to use at least one solvent selected from the group consisting of electrochemically stable ethylene carbonate, propylene carbonate, butylene carbonate, xcex3-butyrolactone, sulfolane, a sulfolane derivative, 3-methylsulfolane, 1,2-dimethoxyethane, acetonitrile, glutaronitrile, valeronitrile, dimethylformamide, dimethylsulfoxide, tetrahydrofuran, dimethoxyethane, methylformate, dimethyl carbonate, diethyl carbonate and ethyl methyl carbonate. They may be used as a mixture.
As the electrolyte for the organic electrolytic solution, preferred is a salt comprising a quaternary onium cation represented by R1R2R3R4N+ or R1R2R3R4P+ (wherein each of R1, R2, R3 and R4 which are independent of one another, is a C1-6 alkyl group) and an anion selected form the group consisting of BF4xe2x88x92, PF4xe2x88x92, ClO4xe2x88x92, CF3SO3xe2x88x92 and (SO2R5) (SO2R6)Nxe2x88x92 (wherein each of R5 and R6 which are independent of each other, is a C1-4 alkyl group or alkylene group, and R5 and R6 may form a ring)
Specific examples of the preferred electrolyte include (C2H5)4NBF4, (C2H5)3 (CH3) NBF4, (C2H5)4PBF4 and (C2H5)3 (CH3) PBF4. The concentration of such a salt in the electrolytic solution is preferably from 0.1 to 2.5 mol/l, more preferably from about 0.5 to about 2 mol/l.
As the separator to be interposed between the positive electrode and the negative electrode, a non-woven fabric or a paper sheet using e.g. polypropylene fiber, polyethylene terephthalate fiber, glass fiber or synthetic cellulose, a mixed non-woven fabric or a mixed paper sheet of such fibers, or a porous film of e.g. polypropylene or polytetrafluoroethylene, may, for example, be suitably used. A porous film is particularly preferred since it has a high strength, a large breaking extension and a low resistance.
The electric double layer capacitor of the present invention may have any structure of a coin type wherein a pair of sheet electrodes with a separator interposed therebetween is accommodated in a metal casing together with an electrolytic solution, a wound type wherein a pair of positive and negative electrodes is wound with a separator interposed therebetween, and a laminate type wherein a plurality of sheet electrodes are laminated with a separator interposed therebetween.
Now, the present invention will be explained in further detail with reference to Examples and Comparative Examples. However, it should be understood that the present invention is by no means restricted to such specific Examples. Here, the material, carbonization and activation conditions and physical properties of the carbon material after the activation in each Example are shown in Table 1, the conditions of imparting mechanical impact force and physical properties of the carbon material thus obtained are shown in Table 2, and the electrode density and the properties of the capacitor are shown in Table 3.

PROCESS FOR PRODUCING A CARBON MATERIAL FOR AN ELECTRIC DOUBLE LAYER CAPACITOR ELECTRODE, AND PROCESSES FOR PRODUCING AN ELECTRIC DOUBLE LAYER CAPACITOR ELECTRODE AND AN ELECTRIC DOUBLE LAYER CAPACITOR EMPLOYING IT


A roofing and/or siding unit and methods are disclosed, the units being formed of an appropriately formulated flexible foamed PVC material, and having a size, overall shape, and exposed surface configuration modeled after a traditional building material unit for which the units of this invention may be substituted (for example shake shingles, or various types of roofing tiles). The units are manufactured by an injection molding process wherein one part of the mold utilized is made by taking a metal casting of the normally exposed surface of one of the traditional building units so that substantial duplicates thereof are produced by the molding process. Since the units produced are similar in size, shape and the like to the traditional type units, workers need no special training regarding their application, which in most applications requires no techniques differing from techniques utilized to apply the traditional building units after which the units of this invention are modeled.

Traditional building materials for covering exterior surfaces of structures, such as walls or roofs, have included, for example, wooden shingles (some of which are known as shake shingles), cementitious tiles, baked clay tiles (for example Spanish tiles) and other well known, often made of naturally occurring, materials. These materials have enjoyed long standing acceptance, due both to their availability and attractiveness, in the trades. As a result of their familiarity, workmen are well acquainted with their use and techniques for their application.
Such materials do, however, have their drawbacks. In most cases, such materials are brittle, and thus subject to cracking and/or breakage upon exposure to adverse conditions, the brittleness of such materials often increasing with age, and are subject to shortened life due to sun and moisture exposure. When replacement is thus required of a unit of such material, large areas of the units must be taken up to effect the replacement.
In the case of cementitious and/or baked clay tiles, their use dramatically increases the load supported by load bearing structures in areas of their application. In the case of wooden materials, additional hazard in case of fire is documented, and, in the case of wooden shingles, their use is discouraged or even banned in some areas where fire danger is high. Wooden materials are also subject to degradation in the presence of fungus, certain insects, and the like, and require a heavier, and thus more expensive, underlayment to assure moisture sealing of the surface.
It would thus be desirable to provide a material to substitute for such traditional materials which is more resilient and flexible (and thus more easily replaced in case of unit failure), comparatively light weight, less susceptible to burning and attack by organisms, and which exhibits better water shedding and/or sealing characteristics, while substantially duplicating the appearance of the traditional materials and requiring no retraining of workers to effect its application to a structure (preferably being applied to a surface in substantially the same manner as the material after which its appearance is modeled).
While a variety of substitute materials have been suggested (see, for example, U.S. Pat. Nos. 4,193,898, 4,226,069, 3,855,753, 4,366,197, 4,015,392, 4,592,185, 4,932,184, 4,343,126, 4,598,522, 4,290,248, and 3,835,609), these have not addressed one or more of the above stated goals, typically providing relatively rigid panel-type units which require special structures and/or techniques for their application to a surface, which do not closely emulate the appearance of the materials substituted for, and which require replacement of an entire panel upon loss of unit integrity, often resulting in inability to match color (due to aging of surrounding panels) and/or undue repair effort and/or expense. Further improvement could thus still be utilized.

Surface covering unit methods of use and manufacture


A process and a continuous casting installation for the production of thin slabs, preferably of steel with a predetermined solidification thickness of, e.g., 50 mm, in which an optimum surface quality and internal quality of the strand with minimal and predetermined solidification thickness and plant capacity, and accordingly minimal rolling effort, is achieved by a qualitative adjustment of casting and rolling in the region of the strand guide, oscillation of the casting mold by a hydraulically operated lifting platform, feeding of casting powder to the mold, and an immersion nozzle with a specific cross sectional area of flow relating to the process and continuous casting installation, resulting in a satisfactory supply of casting slag and bath movement in the cast surface compared with a standard slab with a thickness of 200 mm. These conditions from the crater end to the cast surface exert a direct influence on the superficial and internal quality of the strand and on the reliability of the casting process.

1. Field of the Invention
The invention is directed to a continuous casting installation and to a process for the production of thin slabs.
2. Description of the Related Art
The use of flat immersion nozzles in continuous casting installations is known, for example, from the prior art reference DE 37 09 188 A1. Further, hydraulically driven lifting platforms which allow the stroke, frequency and mode of the oscillation to be changed and optimally selected by deviating from the sinusoidal oscillation during the casting process itself are conventional. Cambered molds are known, for example, from references DE 41 31 829 A1 and DE 37 24 628 C1. Continuous casting and rolling in which the thickness of the cast metal is reduced during solidification so that the internal quality of the strand is improved is known, for example, from reference DE 38 18 077 A1, among other references.
Evaluation of the prior art reveals that the aim of producing thin strands using continuous casting installation requires the solution of complex problems. The totality of influenceable variables with respect to the entire continuous casting installation is so great that the person of average skill in the art is far from knowledgeable enough, and can also not be expected, to find, from the multitude of more or less usable possible solutions, one solution which will lead to satisfactory results in the most economical manner.
The object of the present invention is to provide a process and a continuous casting installation which make it possible to achieve a given thickness of the thin strand by achieving optimum conditions in the slag supply and in the reduction in strand thickness in the mold and in the guide stand during continuous casting and rolling.
The object of the present invention is met by a process for producing thin slabs or strands by casting molten in an oscillating cambered mold using an immersion nozzle, where the immersion nozzle and mold are sized to meet the condition so that                     F        ST                    F        TA               greater than     50    ,
where FST=the strand cross sectional area of a completely solidified slab and FTA=the cross sectional area of an outlet of the immersion nozzle. The process also includes supplying casting powder to the molten metal such that the height of a slag phase hslag at the upper part of the mold is greater than or equal to the height of a portion of a solid strand shell hstrand-shell which penetrates into the slag phase layer at the upper portion of the mold. In other words, the casting powder is supplied such that the solidified strand shell does not penetrate through the upper surface of the slag phase layer at the upper part of the mold. The oscillation stroke, shape, and frequency of the oscillating movement affect how far the solidified strand shell penetrates the upper surface of the slag phase layer and determine the rate of production of the strand. Accordingly, the rate at which the casting powder is supplied during to achieve the above results is dependent upon the oscillation stroke, shape and frequency of the oscillating movement of the mold because these parameters determine the rate at which the strand is produced. A faster production of strand requires a faster rate of supplying of casting powder. The strand which leaves the mold is then reduced directly below the mold in a plurality of steps in a cluster roll stand so that the strand achieves its final thickness while still having a liquid core at the end of the cluster roll stand. The solidification is controlled so that a two-phase zone is present within the strand after achieving the final thickness at the output of the cluster roll stand.
In a further embodiment of the present invention, casting powder which facilitates the formation of slag in the cast surface is supplied so that an active thickness in the cast surface is constant along the entire thickness of the slab.
In another embodiment, both the oscillation characteristics of the mold and the invention, the mold is configured so that the longer pair of sides of a strand exiting the mold outlet comprise a camber such that the sides are slightly curved instead of being flat. The curve is symmetrical about a center axis of the strand. The curved sides produce a difference between the thickness of the strand at the ends of the side and thickness of the strand through the center of the side. This difference in thickness produced by the curved sides is less than 4% of the of the final thickness of the strand.
The object of the present invention is also met by a continuous casting installation including an oscillating rectangular mold and means for oscillating the mold, the means for oscillating the mold being adjustable relative to frequency, stroke and mode of oscillation. The invention casting installation also includes an immersion nozzle arranged to project into the rectangular mold having a cross sectional area that is less than {fraction (1/50)} of the cross sectional area of the completely solidified slab or strand. The casting installation further includes means for supplying casting powder to the mold as a function of the stroke, mode, and frequency of oscillation of the oscillating mold such that the height of the slag phase layer formed at the upper end of the mold is greater than the height of the strand shell which penetrates the slag phase layer. A cluster roll arranged downstream of the mold and includes two rolls that are adjustably arranged at a distance from one another. The cluster roll further includes a hydraulic arrangement operatively arranged for continuously adjusting the distance between the two rolls.
In another embodiment of the present invention, the mold is configured so that from the cast surface to the mold outlet, the thickness of the mold never exceeds 120% of the thickness of the strand at the mold outlet.
In a further embodiment, the two rolls are arranged to have a distance therebetween for reducing the strand thickness as the strand is fed through the rolls. The reduction in thickness reduces the area of the of the liquid interior and therefore creates a flow of the remaining liquid. The flow results in a stirring effect in the remaining liquid interior of the strand with a predetermined strand thickness reduction.
The solution to the problem is not dependent upon the type of mold, e.g., vertical mold, vertical mold with bend, or curved mold.
The invention is described hereinafter by way of example with reference to the drawings.

Continuous casting facility and process for producing thin slabs


The method of cleaning an exhaust gas containing nitrogen oxides including disposing an exhaust gas cleaner comprising a heat-resistant, porous body, which may support a catalyst consisting essentially of (a) at least one of alkali metal elements; (b) at least one of elements selected from the group consisting of Cu, Co, Mn and V, (c) at least one of rare earth elements, in a flow path of the exhaust gas, spraying a liquid hydrocarbon into a stream of the exhaust gas on the upstream side of the exhaust gas cleaner, thereby causing atomized and gasified hydrocarbon to function as a reducing agent for reducing the nitrogen oxides in the exhaust gas.

The present invention relates to a method of cleaning an exhaust gas discharged from internal combustion engines such as automobile engines, etc. and an apparatus for cleaning such an exhaust gas, and more particularly to a method of cleaning an exhaust gas of diesel engines, etc. by efficiently reducing nitrogen oxides in the exhaust gas, and an apparatus for conducting such an exhaust gas-cleaning method.
Recently, environmental pollution has become a serious problem in a global scale, and among them, air pollution such as photochemical smog and acidic rain caused by nitrogen oxides such as nitrogen monoxide, nitrogen dioxide (hereinafter referred to simply as "NOx") in the air is a serious problem. NOx is generated from automobile engines such as diesel engines, and large combustion apparatuses such as cogenerators. Also, fun heaters and other combustion equipments which are widely used at home are sources of nitrogen oxides.
In the case of exhaust gas from gasoline engines, NOx is usually removed by using so-called three-component catalysts. Also, in the case of large, stationary combustion apparatuses such as internal. combustion engines for cogenerators, metal oxide catalysts such as V.sub.2 O.sub.5 are used, and ammonia is introduced into exhaust gas, whereby nitrogen oxides in the exhaust gas are catalytically and selectively reduced.
However, in the case of an exhaust gas having a relatively high oxygen concentration such as those discharged from diesel engines and those discharged from gasoline engines operable in a lean state, efficient removal of NOx cannot be achieved with the above-described three-component catalysts suitable for usual gasoline engines. Also, the reduction of NOx with ammonia introduced into an exhaust gas cannot be applied to movable exhaust gas sources such as automobiles, because this reduction system needs large apparatuses and poisonous, expensive ammonia.
Therefore, it has been desired to develop a method of reducing NOx in the exhaust gas having a relatively high oxygen concentration which is discharged from diesel engines, etc., and various attempts have been made so far.
For instance, there have been proposed methods of reducing NOx in an exhaust gas with a hydrocarbon introduced into the exhaust gas. One example of such methods is disclosed by Japanese Patent Publication No. 44-13002, which comprises passing an exhaust gas through a honeycomb-type ceramic filter carrying a platinum-group metal catalyst while controlling the temperature and flow rate of the exhaust gas, and adding a gaseous reducing fuel (specifically, methane, etc.) to the exhaust gas.
However, this method fails to efficiently reduce NOx in the exhaust gas discharged from diesel engines, etc. According to research by the inventors, even though a hydrocarbon having a small carbon number which is in a gas state in a normal condition, such as methane, propane, etc. is added as an NOx-reducing agent to the exhaust gas discharged from diesel engines, a large removal ratio of NOx cannot be obtained.
There has also been proposed a method of cleaning an exhaust gas, which comprises mixing an exhaust gas containing oxygen and NOx with a hydrocarbon to cause a reaction between oxygen and a hydrocarbon such that the hydrocarbon is partially oxidized to a reducing hydrogen gas and carbon monoxide and to lower the oxygen concentration, the resulting hydrogen gas and carbon monoxide being reacted with NOx in the exhaust gas, thereby decomposing them to nitrogen, carbon dioxide and water (Japanese Patent Laid-Open No. 49-122474). However, since the reduction reaction of NOx should be conducted at a relatively high temperature in this method, it is not suitable for cleaning the exhaust gas of automobiles.
There is an alternative method for reducing NOx which comprises adding a petroleum fuel as a reducing agent to a combustion exhaust gas in a high-temperature region alone or together with part of the combustion exhaust gas with or without air, and adding an air to the combustion exhaust gas in the downstream to reduce NOx in the combustion exhaust gas, the addition of the petroleum fuel such as methane, propane, gasoline, kerosine, naphtha, heavy oil, etc. being conducted by a plurality of steps such that a ratio of the amount of oxygen remaining in the exhaust gas to the amount of oxygen necessary for completely burning the petroleum fuel added is within a particular range (Japanese Patent Laid-Open No. 54-79161).
However, this method cannot remove NOx efficiently without keeping a region where a reducing agent and NOx are reacted at 1000.degree. C. or higher. Thus, this method is also not suitable for cleaning the exhaust gas of automobiles.
There has been proposed a method of reducing NOx by using a catalyst such as zeolite and Al.sub.2 O.sub.3, etc. containing copper, and adding a hydrocarbon having a small carbon number to the exhaust gas (SAE Technical Paper 900496, 1990, and Japanese Patent Laid-Open No. 63-100919). However, catalysts used in this method are poor in heat resistance, durability and low-temperature characteristics, and the method using such catalysts fails to achieve a high reduction ratio of NOx at a low temperature and when the exhaust gas has a high oxygen concentration. Accordingly, it cannot be used for practical purposes.

Method for cleaning exhaust gas containing nitrogen oxides


The present invention is related to a Lactobacillus strain, composition and use thereof for treating autoimmune disease and related complications. The composition comprises at least one isolate of Lactobacillus paracasei strain GMNL-32, L. reuteri strain GMNL-89 or L. reuteri strain GMNL-263, and a pharmaceutical carrier, for treating syndromes and related complications of the autoimmune diseases.

Field of Invention
The disclosure relates to a Lactobacillus strain and an application thereof. More particularly, the disclosure relates to a Lactobacillus strain for treating syndromes and related complications of autoimmune diseases and a composition thereof.
Description of Related Art
An autoimmune disease is a disease that a human body's immune system attacks normal cells of his body. Such patient has weaker normal immunity but stronger aberrant immunity. The "aberrant immunity" refers to the immune system that recognizes the normal cells of its own body as foreign virus or bacteria and targets the normal cells for attacking and clearing them out of the body. The normal immune system of a human body provides a physically protective mechanism to target foreign antigens and abnormal cells, such as tumor cells, for attacking and clearing them out of the human body. However, sometimes the immune system may produce some antibodies against the normal cells or normal cellular components. Therefore, some aberrant excessive inflammation or tissue damage may cause diseases and adversely effect health.
Common autoimmune diseases include coeliac disease, type 1 diabetes mellitus, systemic lupus erythematosus (SLE), Sjögren's syndrome, multiple sclerosis (MS), Hashimoto's thyroiditis, Graves' disease, idiopathic thrombocytopenic purpura, rheumatoid arthritis (RA), aplastic anemia, polymyositis and dermatomyositis, as well as scleroderma.
Among those, systemic lupus erythematosus (SLE) is a chronic systemic autoimmune disease, in which the body's immune system turns against all organs or tissues of the body itself, including skin, joints, heart, blood vessels, liver, kidneys, brain and nervous system. In general, the course of SLE is alternatively aggravated and released, and the onset is usually unpredictable. This disease, which may occur in people of any age, most commonly occurs in young women, and 90% of SLE patients are women. The signs and symptoms of SLE vary greatly in different individuals. When onset of SLE, some patients have severe symptoms with the important organs such as the central nervous system, kidney, heart and so on, whereas some other patient only have mildly joint symptoms during life. As for the incidence, above 90% of the SLE patients have joint pain or arthritis, 70% to 80% of the SLE patients have skin erythema or discoid erythema, 40% to 50% of the SLE patients have pleurisy or pericarditis, 40% to 50% of the SLE patients have lupus nephritis, 20% to 60% of the SLE patients have central nervous system violations, and 20% of the SLE patients have thrombocytopenia.
At present, the cause of the SLE is still unclear, but it is believed that SLE is related to genes, immunodeficiency, viral infections, UV, and drugs. Recent studies have found that, SLE patients have much higher incidence of liver abnormalities (such as hepatomegaly, splenomegaly, jaundice, abnormal liver function, abnormal liver enzymes and so on) and the cardiovascular disease (CVD, such as myocardial infarction (MI)) than normal people, and the atherosclerosis is also highly associated with SLE. Some studies with animal models reveal that significant inflammation and apoptosis of liver and heart occur in SLE mice.
SLE is currently incurable, but its symptoms can be treated. Medicines are important to the treatment of SLE. Physicians prescribe mediation to treat a SLE patient depending on symptoms, the different organ injuries and different severities. Common medications used to treat SLE manifestations include the followings.
(1) Non-Steroidal Anti-Inflammatory Drugs (NSAIDs):
NSAIDs can be used to treat arthritis, pleurisy, and other lighter inflammatory symptoms. Gastrointestinal side effects are the major problem of NSAIDs. Fortunately, a new generation of selective inhibitor of type II cyclooxygenase (COX-2) has been commercially marketed, and it causes much less gastrointestinal side effect than the traditional NSAIDs.
(2) Antimalarial Drugs:
Most commonly antimalarial drug is hydroxychloroquine (or the brand name of Plaquenil). The clinical uses show that the antimalarial drugs have a fairly good efficacy on the treatment of skin symptoms, arthritis, and other mild systemic symptoms of SLE patients. The antimalarial drugs also can decrease the recurrence of SLE.
(3) Cortisol:
Cortisol is generally known as the "American panacea" or "steroids." Cortisol is the most important drugs for treating SLE. Higher dose of steroids should be used in severe conditions of internal organ damages such as lupus nephritis, nervous system lupus, lupus pneumonitis, hemolytic anemia, or thrombocytopenia and so on. The physician also considers supplying an intravenous pulse steroid therapy with high dose of steroids, so that the condition is controlled as soon as possible, and the dose of the steroids is then gradually decreased to a minimal level when clinically well controlled.
(4) Immunosuppressing Drugs:
Immunosuppressing drugs are mainly used to inhibit the activity of the immune system, so as to achieve good control and efficacy of the autoimmune diseases. Immunosuppressing drugs are usually used with steroids, so as to decrease the doses of the steroids and to effectively control the stubborn disease. Common immunosuppressing drugs include azathioprine (Imuran®), cyclophosphamide (Endoxan®), cyclosporine, methotrexate (MTX) and so on.
Probiotics or probiotic bacteria generally refer to live microorganisms originating from human bodies and beneficial to intestinal tract health, or some microorganisms supplied from outside sources and beneficial to human health, for example, lactic acid bacteria (LAB) and some yeasts. 70% of human immune system is located in the digestive tract. As early as the late nineteenth century, Russia scientists have observed that probiotics have health effect to human body. Previous studies have shown that more than ⅓ SLE patients have gastrointestinal symptoms, and 10% SLE patients have gastrointestinal pathological changes at the first onset. It is currently known that probiotics are capable of restoring intestinal flora balance, stimulating mucosal immunity, improving gastrointestinal discomfort and improving urogenital flora.
Recently, some studies attempt to treat SLE with Lactobacillus. The obtained results show that the single Lactobacillus strain can promote the production of anti-inflammatory cytokines such as interleukin-10 (IL-10) and tumor necrosis factor-α (TNF-α), to treat the autoimmune diseases such as SLE.
However, the aforementioned studies seldom investigated whether LABs is used to treat the symptoms of the autoimmune diseases (such as SLE) and their complications (such as cardiac and hepatic disease), and did not propose any regulatory mechanism that LABs may be involved in SLE treatments.
Side effects often occur in drugs for the treatment of autoimmune diseases (such as SLE), and patients with such chronic diseases must be treated and controlled for a long time. Therefore, there is a need to use native Lactobacillus strains to develop products that are capable of treating symptoms and complications of autoimmune diseases, so as to achieve the improvement, control, remedy, or prevention of the patients with the symptoms and complications of autoimmune diseases, as well as the development of other applications of Lactobacillus strains.