Thermal runaway analysis and model of nickel-rich lithium-ion batteries in different overcharging states

Lithium-ion power batteries are favored for their light mass, high energy density and low pollution, but repeated thermal runaway accidents have prevented the large-scale use of lithium-ion power batteries. The thermal safety of lithium-ion batteries is also receiving increasing attention. In this paper, the thermal runaway characteristics of 18650 nickel-rich lithium-ion batteries triggered by heating in different overcharge states are investigated using an extended volume accelerated calorimeter $(\text{EV}+-\text{ARC})$. And the voltage data is collected. The battery's self-heating temperature was examined based on the experimental findings. The time required for the lithium-ion battery from safety valve opening to complete thermal runaway is compared. A thermal reaction kinetics TR model of the thermal runaway of Lithium-ion batteries is developed, and the model curves are in high agreement with the experimental curves.

I. Introduction

The lithium-ion battery market has grown quickly in recent years. Due to their high charging efficiency, fast charging and discharging speed, high energy density and low self-discharge, the creation and use of lithium-ion batteries have drawn an increasing amount of interest. Lithium-ion batteries are core components of electric vehicles and energy storage devices, which can reduce carbon emission and protect the environment [1]. However, Lithium-ion batteries also have major drawbacks: when the temperature is too low, the internal resistance of the battery increases and the capacity decreases, which has an impact on the travel and acceleration of the car [2]–[3]; when the temperature is too high or there are other physical reasons, such as overcharge, over-discharge, puncture, internal short circuit and triggered thermal runaway [4], then the result is a terrible combustion and explosion, which brings great potential danger to people's life and property safety [5]. The temperature of the battery not only changes with the environment, but the battery itself will also heat up and change its own temperature in the working condition. At present, the structure of the battery has been optimized to its limits and only by using new materials is it possible to increase the capacity of the battery and maintain its stability [6].