Bionic capillary/honeycomb hybrid lithium-ion battery thermal management system for electric vehicle

High-capacity lithium-ion batteries have been extensively adopted to extend the driving range of electric vehicles, resulting in more and more severe battery heating. The battery thermal management system is critical to the vehicle's dependability and longevity. An innovative capillary/honeycomb hybrid battery thermal management system (CH-HBTMS) associating bionic cooling channels with cellular cold plates is put forward to enhance the heat dissipation and mass grouping efficiency for prismatic lithium-ion cells. The bionic composite structure coupled multi-branch capillary with honeycomb increases the contact area and distribution uniformity between flow channels and cells, improves the dissipation capacity, which is conducive to the even and rapid heat transfer from the battery, and reduces the failure of phase change material at 40 °C. Compared with the traditional liquid cold plate, the mass grouping rate of the CH-HBTMS increased by 14.11 %. Here, the cooling properties of different cellular metal cooling plates and bionic capillary spatial flow channels are analyzed at 40 °C. A multi-objective optimization is conducted on the battery’s highest temperature, temperature difference, inlet–outlet pressure drop and the mass grouping rate with variables including the inlet mass flow rate, honeycomb plate thickness, porosity and flow channel wall thickness of the CH-HBTMS. The CH-HBTMS with optimal parameters can ensure that the battery’s temperature rises by only 3.38 °C and the cell–cell temperature difference is less than 2.84 °C under harsh conditions and exhibits an excellent heat dissipation performance. This work will help develop the energy-saving and lightweight BTMS for electric vehicles.