Automatic Optimisation of a Battery Pack Cooling Plate

Abstract

Electric vehicle adoption is on the rise which introduces a need for effective battery pack cooling systems. Effective cooling systems play a key role in the battery packs service life. This thesis compares two indirect liquid-cooled cooling configurations and optimises the cooling system in terms of maximum battery cell temperature difference, maximum battery cell temperature and pressure drop. The analysed part of the cooling system consists of aluminium plates with channels, where coolant flows through. One configuration consisting of one large cooling plate and the other of multiple cooling plates. The heat transfer from the battery pack to the coolant was simulated using the commercial computational fluid dynamics (CFD) solver Star-CCM+. Using CFD each battery cells temperature was monitored to evaluate the efficiency of the cooling system. The optimisation involved varying the geometry of the cooling plate channels to study its effect on the heat transfer. The study found that placing cooling plates between the battery cells, rather than placing a single large plate under the battery cells, yielded substantially lower battery cell temperature differences and battery cell maximum temperatures. This is attributed to the interface area having a large effect on the heat transfer and the length of the channels having a large effect on the temperature difference and pressure drop. While using multiple plates the maximum battery cell temperature was decreased by 21.4 K and the temperature difference was 0.452 K lower. Several channel designs were tested based on the results to further improve the multiple cooling plate configuration. The temperature difference and maximum temperature was further reduced by 0.066 K and 0.634 K respectively.