Heat Generation Characteristic of High Power Charging for BEV

With the increasing of the long range of electric vehicles, the high power charging technology over 250 kw is urgently needed to reduce the charging time and improve the convenience of using. However, high power charging is more obvious about generating heat than conventional power, which will affect the battery's charging efficiency, cycle life, and possibly even safety risks. Aiming at the above problems, two typical LiFePO4(LFP) and Li(NiCoMn)O2(NCM) batteries were selected to study the heat production characteristics of energy-based power cells with large power charging based on model and experiment. It is found that the maximum charging capacity of high power charging is greatly affected by the heat management system. Under the condition of forced-air cooling with over 4c-rate charging, the battery heat generation can make battery temperature over 55 degrees, but the water-cooled heat management system can make the battery work in the rated working temperature interval. Under the condition of more than 3c-rate charging, the model's parameter mismatch is serious and the temperature difference between inside and outside is needed to be correction to applied to the high power charging strategy of electric vehicle on line.