What is the main safety concern with lithium-ion batteries?

Himax Decorative Pictures - battery test

Are lithium batteries safe? Generally speaking, the problems of whether lithium batteries are safe are manifested as burning or even explosion. The root cause of these problems is the thermal runaway inside the battery. In addition, some external factors may also affect li ion customized battery packs and cause concerns about whether lithium batteries are safe, such as overcharging, fire, extrusion, puncture, short circuit, etc.

According to statistics, 68% of electric vehicle li ion customized battery packs fire accidents over the years were caused by internal or external short circuits, 15% were caused by charging and discharging, 7% were caused by accidental startup of equipment, and other reasons caused 10%.

From the perspective of the cause of the fire, electrical faults, and spontaneous combustion are the leading causes of fires in electric vehicles, while overcharging, battery cell failures, and short circuits in electrical circuits are the root causes of fires and bring the concern that our lithium batteries are safe.

48V Li Ion Customized Battery Packs

 

Which battery is the safest?

So, are li ion customized battery packs safe? The safety performance of lithium iron phosphate batteries will be higher than that of ternary lithium batteries. This is mainly because the heat resistance of lithium iron phosphate batteries is relatively good, and the thermal runaway temperature can reach more than 800℃.

The battery catches fire primarily due to factors such as short circuits, impact, and overcharging, which drives the concern of whether lithium batteries are safe. When the current passes through, a large amount of heat will appear in the overpotential and ohmic polarization, which will locally heat the battery to the temperature of the thermal decomposition of the cathode. The heat caused the battery to explode and catch fire.

The ignition point of the ternary lithium battery is only 200℃, and the ignition point of the lithium iron phosphate battery is 800℃. After an accident, the collision extrusion temperature can easily exceed the critical value.

In other words, lithium iron phosphate batteries will not spontaneously ignite if they do not reach 800℃. The ternary lithium battery is different. The thermal runaway temperature is basically around 200℃. Looking at the spontaneous combustion incidents of new energy vehicles, most of them are ternary lithium batteries. Therefore, for areas of hot weather, the risk of spontaneous combustion of ternary lithium batteries will be higher.

If you have any question, please feel free to contact us:

  • Name: Dawn Zeng (Director)
  • E-mail address: sales@himaxelectronics.com