Thermoelectrochemical processes in lithium-ion batteries: modeling and analysis

Abstract

Thermoelectrochemical processes in a lithium-ion battery with a graphite anode and an NMC-type cathode were investigated. A mathematical model based on a system of nonlinear partial differential equations was proposed, taking into account charge, heat, and mass transfer processes in the electrodes and electrolyte. The model incorporates electrochemical kinetics described by the Butler–Volmer equation, lithium-ion diffusion, potential distribution, and thermal effects caused by Joule heating and electrochemical reactions. Based on the numerical solution of the DFN model with an integrated thermal module, the spatiotemporal distributions of temperature, current density, and voltage under various load conditions were analyzed. The presence of temperature gradients and nonuniform current distribution affecting battery efficiency, degradation, and lifetime was established. Critical operating conditions characterized by increased internal resistance, local overheating, and reduced system stability were identified. Goal. To develop a mathematical model of dynamic thermoelectric processes in a lithium-ion battery and to evaluate the effectiveness of using a system of nonlinear differential equations for analyzing electrical, thermal, and diffusion phenomena. Methodology. A generalized DFN model with an integrated thermal module (DFN + Thermal PDE) was employed. Numerical methods were applied to solve the system of equations. Results. The dependences of the output voltage on temperature and load current were obtained. The influence of local overheating and nonuniform current density distribution on battery efficiency and service life was determined. Originality. A multiphysics model integrating electrical, thermal, and mass-transfer processes into a unified system was proposed. Practical value. The proposed model can be used for predicting the performance of lithium-ion batteries, optimizing battery design, improving thermal management systems, and enhancing the energy efficiency, reliability, and safety of battery systems.