Temperature Uniformity Analysis of a Cooling Plate With Stepped Trapezoidal Fins Applied to Boiling Battery Thermal Management System

Abstract Noncontact boiling cooling is an effective method for achieving rapid heat dissipation and uniform temperature distribution in lithium-ion batteries (LIBs) during rapid charging/discharging processes. The channel structure inside the microchannel cooling plate (MCP) has a significant influence on the boiling heat transfer performance (BHTP) of the coolant and on the temperature uniformity of the LIBs. Four types of MCPs with different internal structures based on a MCP with a traditional straight channel (TSC-MCP) are proposed in this research: an MCP with single-sided stepped trapezoidal fins (SSTF-MCP), an MCP with bilateral interconnected trapezoidal fins (BITF-MCP), an MCP with bilateral equal-height trapezoidal fins (BEHTF-MCP), and an MCP with bilateral stepped trapezoidal fins (BSTF-MCP). The flow characteristics (pressure drop between inlet and outlet (ΔP) and friction coefficient (f)), boiling heat transfer coefficient (Nusselt number, Nu), total entropy production (Sgen), comprehensive performance (PEC) of the HFE7000 in the MCPs, and temperature uniformity of the MCPs (Tstd) are analyzed at different inlet Reynolds numbers (Re). The optimal MCP type for Tstd and PEC is found to be the BSTF-MCP. Subsequently, the parameters of the decreasing height of the steps and the spacing between adjacent trapezoidal fins in the BSTF-MCP are discussed. Compared with the TSC-MCP, the final BSTF-MCP shows significant improvements in both flow performance and thermal management characteristics. Specifically, ΔP, f, Tstd, and Sgen decreased by 7.59%, 26.53%, 3.83%, and 6.25%, respectively, while Nu and PEC increased by 18.89% and 31.75%, respectively.