Thermal analysis of the cross-sectional shape of lateral liquid-cooling channels for cylindrical cells

Thermal management is crucial to prevent thermal runaway in lithium-ion batteries during high-rate discharge. This study proposes a novel hybrid battery thermal management system (BTMS) combining phase change materials and liquid-cooled microchannels for cylindrical battery packs. First, thermal performance of liquid-cooled microchannels with six cross-sectional shapes is compared. The rectangular cross-section shows the best performance at 1.5 C discharge: maximum temperature of 36.95°C (15.64% lower than hexagonal), maximum temperature difference of 6.79°C (89.54% lower than hexagonal), and pressure drop of 495.67 Pa, indicating lower power consumption. Then, optimisation using comprehensive evaluation factor EI analyses effects of flow rate (v), coolant inlet temperature, and flow direction. Optimal results are: v = 0.2 m/s (EI = 1.578, 26.55% higher than 0.4 m/s), inlet temperature = 30°C (EI 3.25% higher than 15°C), and left-in-right-out flow direction (EI 1.578, 75.92% higher than 2-in-2-out). The BTMS with rectangular channels, phase change materials, 0.2 m/s flow rate, 30°C inlet temperature, and left-in-right-out flow direction balances heat dissipation and power consumption, enhancing battery pack thermal safety.