Analysis of the Heat Generation Rate of Lithium-Ion Battery Using an Electrochemical Thermal Model

Abstract

The operating temperature of a battery strongly affects overall chemical reactions, ion transport, intercalation and deintercalation process, and consequently, efficiency, cycle life, and degradation of battery systems. Therefore, thermal management for battery systems should be optimally designed to secure a highly efficient and reliable operation of the battery systems, which requires characterization and analysis of heat generated during operation. In this paper, a thermal model that includes irreversible and reversible heat source terms is developed and then incorporated into a reduced-order electrochemical model (ROM). The model is validated against the heat generation rate of a large format pouch type lithium-ion battery measured by a developed calorimeter that enables the measurement of heat generation rate and entropy coefficient. The model is seen to be in good agreement with the measured heat generation rates up to 3C from −30 °C to 45 °C. The analysis includes the effects of C-rates and temperatures on the two heat source terms generated during charging and discharging.