Heat-pipe based spray-cooling thermal management system for lithium-ion battery: Experimental study and optimization

Today, performance of lithium-ion battery is still limited by its operating temperature. The upper bound is capped by 50 ^∘C. However, this limit is easily surpassed if batteries work at a high room temperature. In this article, sintered copper-powder heat pipe combining with water spray at its condensation section is designed to attack this issue−The former is sandwiched among batteries, removing battery heat by air convection under normal thermal conditions. When battery operation deteriorates at a room temperature beyond 40 ^∘C, water spray functions for rapid heat dissipation by droplet evaporation. To assess effectiveness of this battery thermal management (BTM) design, discharge of lithium iron phosphate batteries at two large currents, I_d=12.5A and 24 A, are performed at 40 ^∘C. The cooling performance of the proposed BTM system is examined at different air speeds, air relative humidity, spraying frequencies and duty cycles. It is also compared to other heat-pipe based BTM approaches, and tested in transient cycles. The results demonstrate the proposed BTM system is highly effective. In the case of I_d=24A, the maximum temperature and maximum temperature difference of the battery surface are dropped by 29.2 ^∘C and 8.0 ^∘C in comparison to those without BTM aids. It well protects lithium-ion battery operating at a large discharging current in an adverse thermal environment.