This paper proposes an integrated battery thermal management solution combining a heating film and a direct cooling cold plate. Through structural optimization and functional integration, the temperature control performance is significantly improved. In cooling mode, the system reduces the maximum temperature difference between battery cells from 11.4℃ to 8.7℃ . In heating mode, the heating rate can reach 1.1℃ /min, with the cell temperature difference controlled within 5℃ , demonstrating good temperature uniformity. This composite plate features a compact structure, efficie-nt bidirectional temperature regulation capability, and excellent temperature homogeneity, providing a reliable solution for thermal management of electric vehicle batteries under complex environmental conditions.