Numerical investigation on manifold immersion cooling scheme for lithium ion battery thermal management application

Thermal management is very important because lithium-ion batteries generate a lot of heat under high rate charging and discharging. Inspired by the manifold microchannel (MMC) structure for chip cooling, this paper proposes a new manifold immersion (MI) cooling structure used for battery thermal management. The optimization analysis is performed in numerical simulation models. The local convective heat transfer coefficients of the lateral and baffle surfaces are analyzed separately. The results show that unlike the MMC for chip cooling, MI cooling structure's demands high heat transfer in the lateral surface of batteries but not the bottom or baffle surface. Subsequently, the influence of the design parameters on the cooling capacity is analyzed. The results show that the manifold channel length Lch,m and the battery spacing channel width Wch greatly influence the MI cooling performance. Stable wall jet flows are beneficial for MI cooling. It can be formed when Lch,m or Wch is large enough. MI cooling structure requires smaller vortex regions leading to better thermal load and temperature uniformities. The optimized MI cooling structure achieves the maximum temperature of 35.06 °C for a lithium ion battery pack at 5 C discharging, with the bulk temperature non-uniformity θbulk of 6.66 °C, and the surface temperature non-uniformity θsur of 3.52 °C.