For electric vehicle drivers, it happens all the time of recharging the battery away from home. Usually they would choose fast-charging, which can reach 80% SOC within one hour, to satisfy the mobility needs. However with frequency use of fast-charging, they worry whether it damages battery or reduces battery service life.
Lead-acid cell is mainly applied in Micro-electric vehicle. Normal fast-charging model has three steps: constant current charge→constant voltage charge→trickle charge. Even if the battery system is equipped this charge model, large current and voltage will cause heating and deformation of batteries, and also reduce the internal electrolyte, which results in shortening driving mileage and cycle life.
Lithium battery, with light weight and high energy density, now is widely used in electric vehicles. It is a power device generating electric energy by chemical reactions. When fast charging, there is large instantaneous input current and voltage. Battery reduction capacity will lower if fast-charging is frequently used, and then reduce charge/discharge cycle times.
At low temperature, the cycle life of LFP battery will decline, which causes the battery capacity decrease. If the battery’s density is not high enough, fast-charging would worsen it, moreover shorten driving mileage. By contrast, low temperature has little impact on NCM battery. Instead at high temperature the NCM battery has unstable performance. For example, if the temperature is over a certain range of ambient temperature, the battery becomes flammable. At this time input large current, the battery will end in thermal failure caused by one of the battery overheat.
Comparing these two batteries with fast-charging, LFP has high-security than NCM. This is because LFP’s density is low, there is small impact when fast-charging. However NCM battery has small size with high density. It can easily occur oxidation reaction for its active chemical property. When charging temperature is over a certain range of ambient temperature, the battery becomes flammable. So fast-charging has high impact on NCM battery.
Electric car’s battery system is small and high density, and it is more rigorous in battery protection and charging safety, so when charging, there is almost no possibility of battery burning. In contrast, electric passenger vehicles battery system is large, which requires more restrictive safety. Any incorrect use has passive impact on it.
Above all, we should know the battery characteristics when using, and charge at proper temperature.
Company: Zhejiang Godsend Power Technology CO.,LTD
Add:No.268,Kangsheng Road, Qiandaohu Town, Chun’an County, Hangzhou City, Zhejiang Province, China