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

The battery thermal management system is essential to the electric vehicle. In this paper, a battery pack con-sisting 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 differ-ences will decrease once Re further improves. Under 0.5C discharge, the maximum temperature difference (Delta Tmax) 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 Delta Tmax. 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.

Automated summary

The battery thermal management system is crucial for electric vehicles. This study established a battery pack consisting of 20 cylindrical lithium-ion batteries, along with a copper foam/paraffin composite phase change material and liquid cooling channels. A numerical model based on a physical model was built and validated by experimental results. The experimental and numerical tests showed that elevated Reynold numbers (Re) can increase temperature non-uniformity within the battery pack, and temperature differences decrease with further improvement of Re. Under 0.5C discharge, the maximum temperature difference (Delta Tmax) within different cells increased from 0.2 to 1.2 K as Re increased from 0 to 28, and then decreased to 0.4 K as Re increased to 112. The study also revealed the impact of current rate on battery temperature and Delta Tmax. Under different ambient temperatures, liquid cooling was found to be necessary for either warming up the battery in a cold environment or reducing the maximum temperature in a hot environment. Compared to pure phase change material (PCM) cooling, the hybrid PCM/liquid cooling resulted in an 8 K temperature increase and a 13 K temperature decrease at the end of discharge under a low initial temperature of 288 K and a high initial temperature of 318 K.