More and more people are using electric vehicles and green energy sources (solar, wind or geothermal heat) nowadays. These techniques can help solve the energy consumption problem and protect the environment.
However, how to store electricity effectively is still a big issue. Among electrochemical storage systems, Li-ion batteries are found to be a good solution. These rechargeable batteries have higher energy density compared to Lead Acid batteries and Ni/Cd batteries.
Over the past two decades, Li-ion battery technology has been improved a lot, and it has been widely used in electric cars, mobile devices, military, aerospace, and smart grids applications.
Nevertheless, there are several risk factors that can cause battery failure and have harmful effects. A recent review published in Journal of Power Sources summarized these risk factors.
The first risk factor is short circuit. In early stages, the major internal short-circuit issues in Li-ion batteries were resulted from manufacturing defects. Recently, internal short-circuit issues may be developed during use or charging.
The second factor is mechanical abuse. When used in cars, Li-ion batteries may show harmful effects in response to mechanical stresses. Such stresses include car crashes and vibrations.
The third risk factor is overheating. High temperature can change the overall thermal stability of Li-ion batteries and cause thermal runaway threats.
The fourth risk factor is overcharging. Overcharging can severely affect the battery because additional energy is added to the cell beyond the full charge. This can cause thermal runaway and damage the battery function.
Thermal runaway develops dramatically in the Li-ion battery as soon as heat produced in abuse conditions exceeds the heat dissipation capacity of the system.
When cell thermal runaway happens within a battery pack, it can damage the entire pack or battery module.
To solve the safety issues and extending the life of Li-ion batteries, researches suggest that users should keep batteries at room temperature (20 – 25 Co), do not overcharge them, and try to reduce mechanical stresses on the batteries.
The best way to put out a fire caused by Li-ion batteries is using a foam extinguisher. If the fire of a burning Li-ion battery cannot be extinguished, let the pack to burn in a controlled and safe way.
Citation: Abada S, et al. (2016). Safety focused modeling of lithium-ion batteries: A review. Journal of Power Sources, 306: 178-192. doi: http://dx.doi.org/10.1016/j.jpowsour.2015.11.100
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