Experimental studies of reciprocating liquid immersion cooling for 18650 lithium-ion battery under fast charging conditions

In this study, the reciprocating liquid immersion cooling has been proposed and tested for cooling the cylindrical lithium-ion battery (LIB) under fast charging conditions. First, the temperature responses of LIB under fast charging conditions with liquid immersion cooling and natural convection are compared. Experimental results show that the reciprocating liquid immersion cooling possesses better heat dissipation performance than natural convection, not only can precisely control the cell temperature to around 50 °C during fast charging, but also can improve the cell temperature uniformity. Meanwhile, the reciprocating system enables rapid cooling of the battery during the resting process, which consequently achieves asymmetric control of high-temperature charging and room temperature discharging. Then, the effects of different charging rates and different charging protocols are explored, and the high-speed photography is used to observe and record the liquid-gas phase transition phenomenon under three different charging rates. Finally, the temperature response and energy consumption analysis of LIB in the fast-charging process with three different assembly schemes are investigated. This study provides preliminary proof for the advantage of applying liquid immersion cooling for LIB under fast charging.