Impact of Cell Temperature on Battery Aging

No thermal management and asymmetrical heat transfer boundary conditions create a thermal gradient in this 8s 2p Li-ion battery module. As a result, battery cells degrade unevenly. Capacity fades more rapidly in cells that are at higher temperatures. This is an undesirable condition since it leads the module into imbalanced SOC conditions.

The battery cell block is modeled using an equivalent circuit with temperature effects, and a provision for capacity fade and internal resistance increase, both functions of cycle count and temperature.

The module is cycled with a square wave of constant power in both charge and discharge. Current changes direction based on minimum and maximum cell battery state of charge (SOC).

Individual cell capacity is continuously calculated and results show how the higher the temperature, the higher the aging rate.