Electric vehicles are becoming more widely seen on roadways across the world, and they will only become more numerous in coming years. However, while electric vehicles have already come a long way, they still need further development to increase range and to charge quickly before they can become truly widespread. The battery, which is the most vital part of an electric vehicle, is also the most complex and subject to challenges addressing the roadblocks to wider distribution.
Temperature plays an important role in how well a battery will perform. If a battery is too hot, its lifespan is reduced due to chemical processes that alter its cells and accelerate its aging. If it is too cold, its performance is limited. Therefore, engineers must be able to predict the thermal performance of an electric vehicle’s battery pack as well as its electrical performance.
Doing so with the real hardware is not only challenging but expensive. Many issues exist regarding the physical testing of batteries. First of all, a battery’s electrical and thermal behavior is transient, and it may take several hours for the battery to reach a stabilized state, resulting in slow, drawn-out and costly testing. Batteries also change their behavior depending on temperature, age and state of charge. Temperature can be directly measured but age and state of charge must be estimated. Batteries display different thermal and electrical behavior at the beginning and end of life.
In addition, due to the transient nature of a battery’s thermal performance, multiple drive test cycles are needed to predict the impact of a thermal system on battery life. All of these factors make physical testing expensive and time-consuming.
Simulation, however, does not suffer from these issues. As an example of how simulation makes battery testing faster, easier and less expensive, a well-known automotive manufacturer developed a methodology to generate fast-running virtual battery models. Two models were generated: an electrical model and a thermal model.
The electrical model was generated to work with PowerTHERM and designed to predict both the dynamic changes in battery voltage and the heat generation on arbitrary drive cycles. The thermal model was implemented in both PowerTHERM and PowerFLOW. PowerTHERM was used for the conduction and radiation simulation, while PowerFLOW was used to simulate cooling airflow and coolant depending on the details of the cooling system. A reduced order model of the components in the battery pack was also generated for the purpose of quickly exporting the thermal and electrical models to system tools.
The researchers’ methodology was able to work with full-sized packs consisting of dozens of batteries. The models generated were both fast and accurate, allowing the automotive manufacturer’s thermal department to complete analysis of long-duration test cycles, including lifetime thermal predictions. The methodology was part of the company’s focus on developing better virtual engineering processes, and successfully replaced physical testing while saving time, money, and labor and bringing a high-quality electric vehicle to the market in time.
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Magari ya umeme yanaongezeka sana katika barabara za dunia, na idadi yao itaongezeka katika miaka ijayo. Hata hivyo, ingawa magari ya umeme yamepita njia ndefu, bado yanahitaji maendeleo zaidi ili kuongeza umbali na kuchaji haraka kabla ya kuenea kwa kweli. Bateria, ambayo ni sehemu muhimu zaidi ya gari la umeme, pia ni ngumu zaidi na chini ya changamoto za kushughulikia vizuizi vya barabara kwa usambazaji mkubwa. Joto lina jukumu muhimu katika jinsi betri itakavyofanya kazi vizuri. Ikiwa betri ni moto sana, maisha yake hupunguzwa kwa sababu ya michakato ya kemikali ambayo hubadilisha seli zake na kuharakisha kuzeeka kwake. Ikiwa ni baridi sana, utendaji wake ni mdogo. Kwa hiyo, wahandisi lazima waweze kutabiri utendaji wa joto wa betri ya gari la umeme pamoja na utendaji wake wa umeme. Kufanya hivyo kwa vifaa halisi si changamoto tu bali pia ni ghali. Masuala mengi yapo kuhusu upimaji wa kimwili wa betri. Kwa sababu tabia ya umeme na joto ya betri ni ya muda mfupi, inaweza kuchukua masaa kadhaa kufikia hali ya utulivu, na kusababisha upimaji wa polepole, wa muda mrefu na wa gharama kubwa. Betri pia hubadilisha tabia yao kulingana na joto, umri na hali ya malipo. Joto inaweza kupimwa moja kwa moja lakini umri na hali ya malipo lazima kukadiriwa. Betri huonyesha tabia tofauti ya joto na umeme mwanzoni na mwisho wa maisha. Aidha, kutokana na asili ya muda mfupi ya utendaji wa joto ya betri, mzunguko wa mtihani wa gari nyingi zinahitajika kutabiri athari ya mfumo wa joto kwenye maisha ya betri. Sababu hizo zote hufanya upimaji wa kimwili uwe wa gharama kubwa na unachukua wakati mwingi. Simulation, hata hivyo, haina kuteseka kutokana na masuala haya. Kama mfano wa jinsi simulation hufanya upimaji betri haraka, rahisi na nafuu, mtengenezaji maarufu wa magari maendeleo mbinu ya kuzalisha haraka-kuendesha mifano virtual betri. Mifano miwili ilitengenezwa: mfano wa umeme na mfano wa joto. Mfano wa umeme ulitengenezwa kufanya kazi na PowerTherm na umebuniwa kutabiri mabadiliko ya nguvu katika voltage ya betri na uzalishaji wa joto kwenye mzunguko wa gari. Mfano wa joto ilitekelezwa katika wote PowerTHERM na PowerFLOW. PowerTherm ilitumika kwa simulation ya conduction na mionzi, wakati PowerFlow ilitumika kuiga mtiririko wa hewa ya baridi na baridi kulingana na maelezo ya mfumo wa baridi. Mfano wa utaratibu mdogo wa vipengele katika pakiti ya betri pia ilitengenezwa kwa kusudi la kusafirisha haraka mifano ya joto na umeme kwa zana za mfumo. Mbinu ya watafiti iliweza kufanya kazi na vifurushi vya ukubwa kamili vinavyojumuisha miongo kadhaa ya betri. Mifano iliyotengenezwa ilikuwa ya haraka na sahihi, ikiruhusu idara ya joto ya mtengenezaji wa magari kukamilisha uchambuzi wa mizunguko ya mtihani wa muda mrefu, pamoja na utabiri wa joto wa maisha. Mazoezi hayo yalikuwa sehemu ya lengo la kampuni hiyo la kuendeleza michakato bora ya uhandisi wa virtual, na kufanikiwa kuchukua nafasi ya majaribio ya kimwili wakati wa kuokoa muda, pesa, na kazi na kuleta gari la umeme la ubora wa juu kwenye soko kwa wakati. Simulac ina bidhaa nyingi za hali ya juu za simulation, ikiwa ni pamoja na Abacus, Isight, FeSafe, Tosca, Simplr, Simplr, Simplr, Simplr, Simplr, Simplr, Simplr, Simplr, Simplr, Simplr, Simplr, Simplr, Simplr, Simplr, Simplr, Simplr, Simplr, Simplr, Simplr, Simplr, Simplr, Simplr, Simplr, Simplr, Simplr, Simplr, Simplr, Simplr, Simplr, Simplr, Simr, Simr, Simr, Simr, Simr, Simr, Simr, Simr, Simr, Simr, Simr, Simr, Simr, Simr, Simr, Simr, Simr, Simr, Simr, Simr, Simr, Simr. Simulia Learning Community ni mahali pa kupata rasilimali ya hivi karibuni kwa ajili ya programu ya Simulia na kushirikiana na watumiaji wengine. Simulya ni ufunguo wa mawazo ya ubunifu na kujenga maarifa, na Simulya Learning Community inakupa zana unazohitaji kupanua maarifa yako wakati wowote na mahali popote.