Heat Generation Mechanism and Parameter Sensitivity Analysis of NCA-Graphite Battery Based on Electrochemical-Thermal Coupling Model

Abstract

This paper presents an electrochemical-thermal coupling model of 5Ah NCA-graphite pouch battery to analyze the heat generation mechanism. The simulation result indicates that the total heat generation increases with current and the polarization heat is dominant. The total heat generation of negative electrode is higher than that of positive electrode, the electrochemical reaction heat and ohmic heat of positive electrode are higher than those of negative electrode. Then four design parameters were selected, their effects on electrochemical-thermal characteristics and the heat generation from different heat sources were analyzed in detail. The results indicate that the increase of capacity and decrease of discharge temperature can be achieved by decreasing the radius of positive/negative particles (R p /R n ) and increasing the initial electrolyte concentration (c l,0) in a reasonable range. R p and R n are proportional to polarization heat and ohmic heat, R p is proportional to electrochemical reaction heat and R n is inversely proportional. c l,0 does not affect on electrochemical reaction heat, it is proportional to ohmic heat and inversely proportional to polarization heat. The sensitivity order of the design parameters is as follows: R p > R n > c l,0 > SEI film resistance (R sei ).