Enhanced cooling effect of core-shell phase change composite thin film on lithium-ion battery for delaying degradation

Abstract

Thermal management of batteries with high energy density plays a crucial role in enhancing their performance and cycle lifespan. Phase change composites (PCCs) have been highlighted as a passive cooling method to effectively enhance the cooling performance, coupled with an active liquid cooling system for batteries. Albeit their successful demonstration, limited attention has been paid to investigating the temperature characteristics and corresponding degradation delay of the batteries upon the application of PCCs. Herein, we experimentally investigate the cooling effects of a core-shell PCC thin film integrated onto the front surface of a pouch-type lithium-ion battery cell, which is vertically installed on a bottom liquid cooling module. Specifically, the 1.4 mm thick core-shell PCC thin film is successfully fabricated, which exhibits the excellent in-plane thermal conductivity of 47.8 W/(m center dot K) and performs anti-leakage and shape-stable characteristics under the repeated thermal cycles. The 50 times repeated charge-discharge cycles demonstrate that applying the core-shell PCC thin film not only stabilizes the temperature characteristics of the battery cell under high discharge rates, but also suppresses the rise of the internal resistance of the battery cell by 38 % to hold the promise of effective degradation delay for liquid-cooled, high energy battery cells with their secured lifespan.