Li-ion power battery temperature control by a battery thermal management and vehicle cabin air conditioning integrated system

Efficient and effective thermal management of Li-ion battery pack for electric vehicle application is vital for the safety and extended-life of this energy storage system. In this paper, the thermal management system of a battery module is presented as an integral part of the electric vehicle air conditioning system. The refrigerant is bifurcated from the main system through a pipe and expansion valve and guided to the battery module compartment consisting of 64 18650-type Li-ion battery arranged in the form of 8 × 8 array. Several experimental strategies such as expansion valve throttle level, thermostat sensitivity and proportional-integral-derivative (PID) control algorithm are investigated. The results indicate that a larger openness of the throttling valve avoids superheating of the refrigerant and maintains the maximum temperature difference in the battery module around 2 °C. Additionally, thermostat sensitivity and PID control algorithm is found to be able to offer effective thermal management for an electric vehicle battery pack.