If you read enough articles about electric or hybrid vehicles, sooner or later you see references to ultra capacitors. Ultra capacitors are currently widely used in many energy saving devices and have a bright future, including potentially replacing the standard battery. Maxwell Technologies (stock symbol: MXWL) is one of several companies at the forefront of ultra capacitor technology.
First, a brief explanation of what an ultra capacitor is. An ultra capacitor is simply a capacitor with significantly enhanced ability to collect and quickly, very quickly, discharge energy. The charge/discharge cycle for an ultra capacitor can take only seconds. Batteries, by comparison, have a low discharge rate of typically one to ten hours. The ultra capacitors’ quick discharge and charge rate is accomplished by a special carbon coating that is applied to the two electrodes in the capacitor and then immersing the electrodes in an electrolyte.
Maxwell Technologies, based in San Diego, California, is a leading manufacturer of ultra capacitors. Maxwell Technologies’ ultra capacitors are used in many green energy products such as providing burst power to control wind turbines, recapturing and storing recuperative breaking energy in hybrid drive vehicles and for quick acceleration. In addition, their ultra capacitors provide cold start power for trucks, the energy to open aircraft doors in the event of power failure and back-up power supply for uninterruptable power sources.
Last year, Maxwell Technologies won a $1.7 million contract from Defense Advanced Research Projects Agency (DARPA) to develop along with the University of Massachusetts and the US Navy a “hybrid ultra cap” that combines ultra capacitors and batteries to store and quickly distribute energy and is light and small enough to be carried by soldiers in the field. Since conventional batteries can store more energy at this time the hybrid approach is preferred. In addition to allowing a quicker discharge, an ultra capacitor also brings other advantages over a conventional battery. One of several drawbacks of using conventional batteries is that after repetitive use they lose their ability to hold energy; they are slow to charge. Also they work best in a narrow temperature range. Ultra capacitors use a “mechanical” charge system instead of a “chemical” charge system and thus do not face these limitations.
For these reasons, a “hybrid ultra cap” is a step towards the Holy Grail for ultra capacitors, which is to increase their energy storing capacity and eventually replace batteries. While this technology may be years away it holds tremendous promise for such areas as electric vehicles as well as many other applications and as such Maxwell Technologies is a company to keep your eye on as they continue to develop their ultra capacitor technology.
Disclaimer: This article is intended to be informative and should not be construed as personalized investment advice. You are responsible for your own investment decisions.
Disclosure: The author has no position in Maxwell Technologies and no plans to initiate a position in the next 72 hours.