Efficient thermal management strategy of Li-ion battery pack based on sorption heat storage

An efficient battery thermal management system (BTMS) is crucial to ensure the working temperatures of the battery are within a suitable range and therefore guarantee performance. However, the current BTM methods not only are limited by weight, space, and energy consumption, but also hardly surmount the contradiction of battery cooling at high temperatures and battery heating at low temperatures. In this work, an innovative passive BTM strategy of Li-ion battery (LIB) pack based on sorption heat storage is numerically investigated. The as-synthesised thermochemical sorbent is supposed to be fabricated as a porous coating layer of batteries to regulate the temperature of the LIB pack, and the pack temperature evolutions under high discharge rates of 3C, 5C, and 7C are analysed. A multi-physics model, coupling electrochemistry of battery, fluid flow, heat transfer, and chemical reaction, is developed to study the dehydration/hydration processes in a proposed BTMS. These multi-physics fields are solved by using the finite element method discretisation approach. Compared to traditional BTMS based on phase change materials (PCMs), this sorption thermochemical-based BTMS can control the battery pack below 55℃ under these high discharge rates due to the prominent advantage of high desorption enthalpy. The maximum temperature differences of the pack using sorption BTMS are 0.8, 1.2, and 1.7 ℃, lower than that of PCM-based BTMS, and a fast temperature lift of ∼ 11℃ can be achieved for the LIB pack in the cool environment thanks to the exothermic adsorption effect. The sorption BTMS can adaptively achieve cooling and preheating of LIB pack and thus maintain the pack works under the desired temperature range. The results of this study may provide a new strategy and prediction on BTMS based on sorption heat storage.