A novel battery thermal management based on composite phase change material with liquid-assisted cooling for different ambient temperatures

In this work, a thermal management system (TMS) employing the combination of composite phase change material (CPCM) and liquid cooling was developed for a lithium battery module. To enhance the temperature uniformity of the battery module, a new strategy was proposed creatively, which varied the thermal conductivity of the CPCM wrapping the battery depending on the position of the battery. Firstly, the thermal conductivity of CPCM was optimized for a single battery thermal management. Then, the temperature control effects of the proposed TMS were investigated numerically on the battery module. Results indicate the thermal conductivity of CPCM should not be more than 3 W/m & sdot;K. At 40 degrees C of ambient temperature, the only CPCM cooling can maintain the surface temperature of battery with 5C discharging within 44 degrees C, presenting excellent uniformity. At 45 degrees C, CPCM fails and liquid cooling can inhibit the temperature rise of the batteries, but increases the temperature inconsistency. Compared to the CPCM with constant thermal conductivity (3 W/m & sdot;K), the surface temperature difference of the battery module decreases from 5.30 to 2.95 degrees C employing CPCM with varying thermal conductivity (0.6-3 W/m & sdot;K). Decreasing coolant temperature can reduce the battery module temperature, but increase its temperature difference. The effectiveness of the varying lambda CPCM on the temperature uniformity of a battery module has also been verified by the designed experiment. This study can potentially provide significant guidance to the design of a lithium battery module based on the coupling CPCM and liquid cooling.