The thermal performance of a novel internal cooling method for the electric vehicle battery: An experimental study

The Li-ion battery (LIB) with the innovative internal cooling methods is designed to substitute for the NCCB used in electric vehicles (EVs). In this paper, the NiCoMn battery with a hollow mandrel is fabricated. The pure phase change materials (PCM) and heat pipe (HP) assisted PCM are filled in the mandrel, respectively, to constitute the PCM internal cooling battery (PICB) and the HP-PCM internal cooling battery (HPPICB). Experimental investigations are conducted to assess the thermal performance of the as-constructed battery. A complete cycle with low charge and discharge currents is used to measure the capacity of the manufactured battery. Then the proper mandrel diameter of PICB is obtained by calculation and experiment methods. The thermal behaviors of natural convection cooling method (NCCB), PICB and HPPICB are estimated by comparing their maximum temperatures as well as the temperature uniformity. The feasibility and efficiency of the batteries in practical applications are further taken into consideration by a cycling test. The experimental results demonstrate that NCCB shows the worst performance at all conditions due to its low efficient cooling system. While relying on the heat storage ability of the PCM, PICB with 6 mm mandrel diameter exhibits a moderate performance. Further, the HPPICB possesses the best thermal performance by means of integrating the PCM with the heat pipe.