Optimum cooling surface for prismatic lithium battery with metal shell based on anisotropic thermal conductivity and dimensions

Battery thermal management system (BTMS) is important for the battery pack in electric vehicles. Existing literature focuses on the structure of BTMS but not on the selection of the optimal cooling surface of the battery. To the authors' knowledge, this study first investigates the optimum cooling surface for prismatic lithium battery based on anisotropic thermal conductivity, dimensions, and metal shell. The specific heat, thermal conductivity, and heat generation are measured experimentally to establish a three-dimensional (3D) shell cell separation numerical model. Results show that aluminum shell plays the role of fin and enhances the cooling effect. Cooling on surface B has better effect when the aluminum shell thickness is less than 0.3 mm; otherwise, cooling on surface A is better. The cooling effect can be improved by increasing the thickness and area of aluminum shell. Battery temperature rise reduces by 67.5% when the thickness changes from 0 mm to 1 mm. A negative linear correlation exists between the temperature rise of the battery and the cooling area. Double surface cooling reduces the temperature rise by 24.1% compared with single surface cooling. The investigation on optimal cooling surface can guide the selection of cooling form of BTMS.