Experimental and numerical investigation of a hybrid battery thermal management system based on copper foam-paraffin composite phase change material and liquid cooling

The battery thermal management system is essential to the electric vehicle. In this paper, a battery pack consisting of 20 cylindrical lithium-ion batteries, along with the copper foam/ paraffin composite phase change material, and liquid cooling channels were set up. A numerical model was built based on the physical model, which was validated by the experimental results. The experimental and numerical test revealed elevated Reynold numbers (Re) will increase temperature non-uniformity within the battery pack, while the temperature differences will decrease once Re further improves. Under 0.5C discharge, the maximum temperature difference (ΔTmax) within difference cells increased from 0.2 to 1.2 K as Re increased from 0 to 28, then it decreased to 0.4 K with Re increased to 112. The study on the current rate effect revealed that a higher current rate could lead to both higher maximum battery temperature and higher ΔTmax. Under different ambient temperatures, liquid cooling is necessary as it can help with warming up the battery in a cold environment or reducing the maximum temperature in a hot environment. Compared with pure phase change material (PCM) cooling, at the end of discharge, the hybrid PCM/liquid cooling formed an 8 K temperature increase and a 13 K temperature decrease under a low initial temperature of 288 K and a high initial temperature of 318 K, respectively.