Fire Safety of Lithium-ion batteries in electric vehicles

Consumers’ biggest concerns with all-electric cars are about the limited range of the battery and how long it will take to recharge. In response, car manufacturers are working actively on developing more powerful batteries. But the possibility of a thermal runaway event occuring in the lithium-ion battery system is much more worrying. The risk increases as the batteries get more powerful. A thermal runaway causes smoke, fire, and even explosions, and threatens the car and its occupants.

Each cell in a lithium-ion battery contains flammable electrolyte. This is the liquid membrane through which chemical ions pass between electrodes. Thus if a single cell short-circuits this electrolyte can catch fire and burst through battery cell walls.

Since 2015, when the electric-vehicle market became more mainstream, many battery-related accidents have been recorded.

One of the biggest challenges in desiging an EV architecture is determing how batteries will react in a crash. Second question is how to prevent the resulting fire from intruding into the battery pack. The temperature of a EV battery fire can go up to 1000°C (1832 °F) In case of a crash and fire, occupants in the vehicle need time to escape.

A way to handle this is to place the batteries not too close to the sides of the vehicle. Unfortunately, this alone will not be effective in case of a real car crash. The highest level of fire protection can be achieved by adding specially designed insulation to the sides of the battery cells, modudels and/or packs.