Thermal characteristics of Li-ion battery based on phase change material-aluminum plate-fin composite heat dissipation

Abstract

A reliable battery thermal management system (BTMS) not only can effectively decrease the maximum temperature but also maintain the temperature uniformity of the lithium-ion (Li-ion) battery after grouping. Nevertheless, considering the deficiency of a single heat dissipation method, there exist challenges in efficient heat dissipation structure design, especially at high discharge rates. In this work, a composite heat dissipation structure of battery module with phase change material (PCM)–aluminum plate–fin is proposed. Meanwhile, the transient effects of different discharge rates, melting points, and thickness of PCM on the thermal characteristics of the module are analyzed. Results show that the maximum temperature of the module with PCM–aluminum plate–fin can be reduced by 25.8°C, 11.0°C, and 10.2°C respectively at 4 C discharge rate compared with natural convection, aluminum plate–fin, and paraffin PCM, and the maximum experimental error among them is less than 5%. During 2–5 C discharging, the melting rate of phase change increases first and then decreases, which leads to the trend of the maximum temperature and maximum temperature difference of the module rising with bending twice. When the ambient temperature is 25°C, the paraffin PCM with a melting point of 28°C is implemented for battery cooling because of its more rapid melting and heat absorption. The increase in PCM thickness is beneficial to the heat dissipation of the module. The optimal PCM thickness of 3 mm can realize temperature uniformity control within 2.5°C.