Numerical study of two heat exchangers for the cooling of a battery pack for an electric vehicle

Abstract

Background: The thermal management of a battery pack designed for an electric vehicle is a key to prevent accidental events and ensure a long lifespan of the batteries. A typical accident is a thermal runaway of one or more cells in the battery which can cause fire or explosion of the battery pack. This paper presents a numerical modelling of a battery pack (BP) and its heat exchanger (HE) for an electric vehicle. The heat produced in the battery is evacuated by the HE. Methods: Two different kinds of modelling have been realized: a computational fluid dynamic (CFD) modelling and a coarse (called MOD3 for 3D Model) modelling. The CFD modelling allows the creation of fine numerical simulations of a BP, but uses large meshes, therefore the cost of each calculation is important. In order to make a large number of quite long transient simulations, a second tool called MOD3, employing only a coarse mesh, was developed in this study at the Commissariat à l’énergie atomique et aux énergies alternatives (CEA). Results: Two measurement campaigns corresponding to two different versions of the HE have been conducted at CEA. The temperature measurements allow comparisons of MOD3 to a real battery pack and to fit some heat exchange coefficients. The cells temperatures as well as the cooling liquid temperature are compared. Conclusions: The MOD3 tool has been fitted partly on CFD calculations, and partly on experimental measurements. It will be integrated in a machine learning environment by CIDETEC to take into account the thermal management of the BP in real car simulations.