Numerical optimization of the cooling effect of a bionic fishbone channel liquid cooling plate for a large prismatic lithium-ion battery pack with high discharge rate

Lithium-ion batteries are discharged at high rates in specific applications, such as unmanned aircraft and emergency start-up power. But, the temperature of lithium-ion batteries significantly increases at high discharge rates. In this study, four liquid cooling plates with bionic fishbone channels were designed to address the thermal phenomenon of high temperature rise and non-uniform temperature distribution in large prismatic lithium-ion battery packs during 6C large rate discharge. Additionally, their influences on the cooling performance of the battery thermal management system (BTMS) were investigated. The results demonstrated that the single inlet and double outlet symmetric bionic fishbone channel (D2) liquid-cooled plate exhibited optimal cooling performance. Furthermore, it was compared to the previous Z-type liquid cooling plate, confirming its performance advantages. Subsequently, orthogonal experiments were performed to study the influences of the D2 liquid-cooled plate structure and mass flow rates on the cooling performance of the BTMS. The optimal structure's parameter combinations obtained from the comprehensive equilibrium analysis were flow channel width (W) = 4 mm, inlet flow channel width (L) = 12 mm, flow channel angle (θ) =70°, and mass flow rate (F) = 0.0175 kg/s. The maximum temperature (Tmax) and temperature difference (ΔTmax) of battery pack and the pressure drop (ΔP) of the liquid-cooled system under the optimal structure was decreased by 0.84 %, 5.15 %, and 19.16 %, respectively, compared with that of the initial structure of D2 liquid-cooled plate.