Abstract:

The finite element analysis method is used to construct the lumped parameter model of a 18650 lithium-ion battery pack and the key battery parameters through constant current discharging experiments are obtained.The research on the temperature distribution under the aging inconsistent state of the battery pack is focused on.The results show that the high internal resistance of the aged battery leads to significantly higher maximum temperature than other individual cells in the pack.During discharge at 1 C,the maximum temperature rise of the aged battery reaches 13 K.Additionally,the higher the discharge rate of the battery pack,the greater the impact of aging on the maximum temperature rise and temperature consistency of the battery.When the discharging rate reaches 3 C,the temperature inconsistency within the pack reaches 2.09 K.The research results are of certain significance for designing and optimizing battery thermal management systems.

Key words: 18650 lithium-ion battery, lumped parameter model, temperature distribution, battery aging