Novel leaf-like channels for cooling rectangular lithium ion batteries

Abstract

To provide a favorable temperature for a Li-ion battery liquid cooling system, novel leaf-like channels with loops were designed as the dispersed layer. Furthermore, four collection channels along diagonal lines were established to decrease the temperature gradient, which formed a double-layer cooling channel. The effects of four structural parameters (width ratio, length ratio, bifurcation angle and channel thickness) on maximum temperature and surface standard deviation were investigated. In addition, the influence of the inlet mass flow rate was also discussed. The obtained results demonstrated that optimal maximum temperature and temperature uniformity were achieved at a width ratio of about 3/4, a length ratio close to 0.5 and a bifurcation angle in the range of 30–50°. Moreover, the thickness of the cooling channel had a strong effect on the pressure drop but only a little on the heat transfer. Increasing inlet mass flow rate can obtain the required heat dissipation capacity but at the expense of pressure drop. In summary, the synergistic effect of thickness and inlet mass flow rate can satisfy the requirements of both heat dissipation and power consumption. This optimized design can decrease the maximum temperature from 60 °C to 32 °C and the standard deviation of surface temperature from 7.1 °C to 1.4 °C. These simulation results are helpful for the design of cold plates with fractal networks.