The battery thermal management system represents the fundamental component of the power battery, serving as the foundation for ensuring its safe operation. Consequently, it is imperative that researchers continue to investigate this field in order to guarantee that the system is capable of meeting the demands of the present era. This study proposes a new strategy for battery thermal management that utilises solid-liquid phase change material (PCM) and heat pipe-fin coupled liquid cooling. A heat pipe is inserted into the centre of a battery pack filled with PCM, while fins act as a heat sink skeleton to enhance overall heat dissipation. The fins connect the heat pipes to the liquid cooling plates, creating a connected heat dissipation system. The experimental results show the temperature variations and distributions of the battery pack at different discharge multiples. Additionally, the performance and effectiveness of each part of the system are analysed. The experiment demonstrates the feasibility of the proposed system and its ability to ensure the safe operation of the battery pack. The optimized system has advantages in reducing the maximum temperature and improving temperature uniformity. After 10,000 seconds of operation under 1C and 2C conditions, the maximum temperature of each part of the battery pack was reduced by 26.5% and 15%, respectively, compared to the pre-optimisation temperature. Additionally, the average temperature of the system remains below 45°C even at a discharge rate of 2C. The temperature uniformity between the battery pack parts has also greatly improved, with a maximum temperature difference of 0.68°C and 1.31°C under 1C and 2C conditions, respectively.