Effect of Cooling the Cathode Grid Tab Stack on the Thermal Characteristics of Lithium-Ion Pouch Cells under Various Discharge Rates of Constant Current

Abstract

The aluminum tab on the cathode of Lithium-Ion pouch cells has a higher electrical ohmic resistance than the copper tab on the anode side. More importantly, the cathode grid tabs form a joint with the cell’s electrode, which is a source of Joule heating that can exacerbate thermal gradients within the cell core thus affecting the cell performance. In this research, the heat generated at the cathode tab joint of a 14Ah Lithium ion phosphate pouch cell has been quantified and their effect on the cell’s thermal gradients was studied during 3C and 8C rates of discharge. It was found that a thermal management system that removes the cathode grid tab heat can lower the overall cell temperature. However, at a 3C rate discharge, the removal of cathode tab heat can induce a greater thermal gradient within the cell core.