More and more vehicles on our roads are electric or hybrid vehicles (EV and HEV) as there is a global transition to renewable fuels. Knowledge is limited about fire risks with vehicles having these new energy sources. Consequences connected to risks of Li-ion batteries in case of a malfunction may imply serious outcomes, for example, if the driver is affected by gas emissions or by fire/explosion and therefore more research in this area is needed.
Storing large amounts of energy, whether it is in large batteries used in energy-storage applications or batteries used in electric vehicles can be inherently dangerous as energy stored in a confined space tries to escape, sometimes violently. As a result, Li-ion batteries are susceptible to spontaneous ignition and subsequent explosion due to overheating. Overheating may be caused by electrical shorting, rapid discharge, overcharging, manufacturing defects, poor design, or mechanical damage, among many other causes. This might cause thermal runaway and the release of a flammable electrolyte. A thermal runaway produces enough heat to cause adjacent battery cells to ignite thus producing a fire that repeatedly flares up at each cell. Li-ion fires have different characteristics and spread quickly in comparison to normal fires which makes extinguishing very difficult.