Experimental study of battery passive thermal management system using copper foam-based phase change materials

Lithium-ion batteries (LiBs) have been widely applied in electric vehicles (EVs) and energy storage devices. The battery thermal management system (BTMS) critically impacts the safety and degradation of LiBs. Phase change material (PCM) is a promising passive BTMS solution owing to its high latent heat and non-parasitic power consumption requirements. In this paper, paraffin (PA) as the PCM was embedded in the copper foam to enhance the heat dissipation of the cooling material. The thermal responses of the battery module were comparatively investigated under different thermal management solutions, including natural air, pure PCM, and copper foam-PCM. A battery module consisting of 16 thermal dummy cells (TDC) was designed, built, and calibrated to replace real commercial 21700 NMC battery cells. The findings indicates that the proposed copper foam-PCM solution effectively enhances heat dissipation and improve the temperature uniformity of the battery module. For instance, in the condition of intensive operation (60% depth of discharge and 3C discharge), copper foam-PCM composite material reduces the maximum temperature rise from 57.4°C to 51.4°C (-10.4%) compared to pure PCM. At ambient temperatures of 25°C and 35°C, the temperature inhomogeneity of the battery module with copper foam-PCM is maintained within 5°C and 2°C, respectively. Besides, the effect of copper foam-PCM cooling on the cell-to-pack conversion efficiency was evaluated. The gravimetric cell-to-pack ratio (GCTP) and volumetric cell-to-pack ratio (VCTP) of the battery pack employing the proposed BTMS reached 53.1 % and 45.6 %, respectively.