Simulink-based Electrothermal Coupling Simulation Analysis of Lithium-ion Batteries under Overcharge Conditions

Overcharging-induced thermal runaway in lithium-ion batteries is the primary cause of battery safety issues in lithium battery energy storage power stations. This study conducted a 100 A overcharge experiment with a 280 A·h lithium-ion battery to obtain voltage and temperature data from the process from overcharge to thermal runaway. Using a Simulink first-order resistor-capacitor equivalent circuit model of the battery and the internal heat generation mechanism of lithium batteries, as well as utilizing state of charge (SOC) to construct a segmented fault heat generation model, the abnormal heat release characteristics of lithium batteries under normal and extreme overcharge conditions are investigated with a temperature-triggered thermal convection heat dissipation module. Dynamic tracking of the increase in battery thermal runaway temperature is achieved. The model simulated rates of 1C and 0.5C for a 100 A·h battery, with accuracy validated against relevant experiments. Simulations using different rates on the 280 A·h battery explored the relationship between the peak thermal runaway temperature, time to peak temperature, and SOC. Temperature-voltage errors across different specifications and rates in both experiments and simulations are within reasonable ranges. The constructed model accurately reflects the electrothermal coupling characteristics at each stage of the thermal runaway process.