# Simulation of Dispersion and Explosion Characteristics of LiFePO4 Lithium-Ion Battery Thermal Runaway Gases

## TL;DR

This paper studies how thermal runaway in lithium-ion batteries can lead to dangerous gas dispersion and explosions, affecting safety in energy storage systems.

## Contribution

The study provides new insights into how the number and location of thermal runaway batteries impact gas dispersion and explosion risks in energy storage systems.

## Key findings

- Simultaneous thermal runaway in 48 batteries leads to combustible gas reaching explosive levels in 9.8 seconds.
- Explosion overpressure at the hatch can reach 583 kPa when the fire is farthest from it.
- Explosions from 48 batteries can produce over 40 kPa at 5 meters, posing serious injury risks.

## Abstract

In recent years,
as the installed scale of battery energy storage
systems (BESS) continues to expand, energy storage system safety incidents
have been a fast-growing trend, sparking widespread concern from all
walks of life. During the thermal runaway (TR) process of lithium-ion
batteries, a large amount of combustible gas is released. In this
paper, the 105 Ah lithium iron phosphate battery TR test was conducted,
and the flammable gas components released from the battery TR were
detected. The simulation tests of the diffusion and explosion characteristics
of lithium iron phosphate battery’s (LFP) TR gases with different
numbers and positions in the BESS were carried out using FLACS simulation
software. It was found that the more batteries TR simultaneously,
the shorter the time for the combustible gas concentration in the
energy storage cabin to reach the explosion limit. When 48 batteries
were in TR simultaneously in the energy storage cabin, the shortest
time was 9.8 s, and the further the location of the fire is from the
hatch, the largest explosion overpressure is generated to the hatch,
up to 583 kPa. When the gas generated by the TR of 48 batteries explodes,
the maximum explosion overpressure at 5 m outside the energy storage
cabin hatch is more significant than 40 kPa, which will cause serious
injury to humans. The causes of TR of batteries in prefabricated chambers
are complex, and the location and amount of thermal runaway of batteries
as well as the diffusion of combustible fumes can have different effects
on the external environment. The research results can provide support
for the safety design of BESS.