A comprehensive study for evaluation of cell cooling coefficient of the batteries of fixed sizes and batteries with defects in manufacturing

Abstract

For the evaluation of cooling performance of Li-ion battery thermal management systems, the commonly used metrics are lumped thermal conductivity, thermal conductance, Biot number, etc. However, such metrics are limited to describing the thermal performance of Lithium-ion batteries (LIBs) and expressing the heat rejection from a body generating heat within its volume. In this perspective, a new metric, such as cell cooling coefficient (CCC), can be introduced to measure the heat rejection capability of cells, which can be used to formulate efficient thermal management strategies. However, limited works describe the system's thermal performance based on CCC, which needs thorough investigation. This work illustrates a comprehensive heat conduction simulation using heat flux through electrode tabs, average temperature of electrode tabs, max cell temperature, total CCC, and the electrode CCC as the thermal indexes to describe the thermal behavior of batteries with five manufacturing defects and study the correlation between heat rejection performance and the CCC of the system. The results of the analysis claim that batteries with different manufacturing defects have different CCC values and thermal performance. Increasing the width of electrode tabs can increase the total CCC of the system, reduce the difference in the electrode CCC values, and further decrease the max cell temperature. The total CCC and the difference in the CCC value of each tab of the battery can be applied to describe the heat rejection performance of the system. The findings of this work can guide further work on optimizing the structure to improve the thermal performance of the cell.