With the rapid development of electric vehicles, energy storage systems and other fields, the requirements for the safety and reliability of large-capacity lithium battery modules are getting higher and higher. Among them, phosphorus acid lithium-ion battery module due to its high safety performance and cycle life, it has become a technology that has attracted much attention. However, the lithium iron phosphate battery module may lose control of heat under extreme conditions, posing a potential threat to the safety of equipment and personnel. Therefore, studying the thermal runaway phenomenon and its mechanism of large capacity lithium iron phosphate battery module has become an important topic at present.

1. Thermal runaway phenomenon and mechanism

thermal runaway refers to the violent exothermic reaction generated by the battery module under abnormal conditions, such as overcharging, overdischarging, external damage, etc., resulting in rapid temperature rise, eventually triggering combustion, disastrous consequences such as explosion. The thermal runaway mechanism of large capacity lithium iron phosphate battery module mainly includes the following points:

1.1 internal short circuit

metal particles or electrolyte pollutants inside the battery may cause internal short circuit, causing concentrated release of overcurrent and heat, thus leading to the occurrence of thermal runaway.

1.2 overcharge and overdischarge

1.3 External damage

the battery module may cause external damage such as collision and puncture, resulting in short circuit of the positive and negative poles inside the battery, thus causing thermal runaway.

2. Research methods of thermal runaway

in order to study the thermal runaway behavior of large capacity lithium iron phosphate battery module, scientists and engineers have carried out a series of research work. The following are some commonly used research methods:

2.1 Thermal runaway experiment

through designing and conducting thermal runaway experiments, the thermal runaway process of the battery module under abnormal conditions is simulated. Through experiments, key parameters such as temperature, time and heat release rate of thermal runaway can be obtained, providing data support for subsequent simulation and analysis.

2.2 Numerical Simulation

using numerical simulation method, establish the thermal runaway model of the battery module, and simulate and analyze the thermal runaway process. Through numerical simulation, the occurrence time, temperature distribution, heat release rate and other information of thermal runaway can be predicted, which provides basis for the design and safety evaluation of battery modules.