Enhancing thermal strategy imply to first measure and analyse the full thermal behaviour for the vehicle battery pack and then to build up a complete numerical model. This has been realized for iHeCoBatt project using the CEA’s facilities in Nantes (France) and CEA’s expert team in Grenoble (France). The first part has consisted in acquiring internal and external temperatures for different test profiles and external conditions. CEA’s facilities rely on a climatic chamber coupled to an electric power bench (Fig.1 and Fig.2). Several electrical profiles were imposed to the battery in order to fully define the thermal response of it, starting from the internal component, up to the entire system. Constant charging modes for a fixed range of SOC (State Of Charge), Constant cycling modes up to thermal equilibrium, fast charging modes and even emulating a fully dynamic electric solicitation were realized for several external conditions.
These data have then been used to highlight the influence of all component in the battery pack using full CFD (Computational Fluid Dynamics, Fig.3). Numerical models enable analysing heat diffusion within a cell module, fluid flow within the heat exchanger, the natural convection impact through the small residual air gaps in the battery pack. Finally it enables to give inputs for a more coarse modelling approach based on Matlab/ Simulink (Fig. 4), integrating the aside ancillary elements (chiller, pump). The latter will be used to quantify the impact of the different thermal management strategies on the vehicle range.
