When summer comes, as the temperature rises, the season of “spontaneous combustion” of electric vehicles is coming. Electric vehicle owners, considering the potential danger of spontaneous combustion of vehicles, should be more cautious when charging their cars.
According to the data by the Fire and Rescue Bureau of China’s Emergency Management Ministry, there were 640 electric vehicle fires reported in the first quarter of 2022 in China, 32% more than in 2021, much higher than the average increase of 8.8% for vehicle fires in general. On average, there are at least 7 new-energy vehicle fire cases every day in China.
At about 11:30 p.m. on May 12, a fire broke out at an electric vehicle charging station in Guangzhou, causing damage to three cars. As shown in live videos, the fire was raging in the parking shed, accompanied by thick smoke and explosions, but fortunately no one was injured.
According to the fire department: three cars were found badly burnt. At present, the brands of the burnt vehicles are not yet known. Firefighters remind electric vehicle owners not to charge outdoors in heavy rain, and the charging time should not last too long if charging in raniy days is not avoidable.
Battery Thermal Runaway Temperature
The team of Academician Ouyang Minggao found that the stability of the power battery will be significantly deteriorated after 300-500 times of fast charging. Generally, the thermal runaway temperature of a new battery is 215 degrees Celsius, while the critical point of the thermal runaway temperature of the battery that used to be fast charged many times might be greatly decreased to 107 degrees Celsius.
A common BEV (battery electric vehicle) can be charged 300 times in its life time and will have an actual range of 400km once fully charged. Once an approximate driving distance of 120,000 kilometers is reached, they will face the problem of a sharp drop in the critical point of thermal runaway temperature and a sharp increase in the probability of spontaneous combustion. At the same time, in pursuit of longer battery life, the battery is getting bigger and bigger; in order to shorten the charging time, the EVSE power is getting higher and higher. Naturally, the probablity of battery charging accidents is also increasing.
Firefighters also reminded that since the cells are in the battery pack, even if the external fire is extinguished, the internal cells may still be burning. Therefore, after the surface fire is extinguished, firefighters should continue to cool the battery or even dismantle it to avoid reburning. Therefore, without professional fire extinguishing methods to extinguish the battery fire, we can only watch the vehicle being burnt into a pile of scrap metal.
Tips to Charge the Electric Vehicle in Summer
In addition, for the owners of electric vehicles, how to prevent the spontaneous combustion of the vehicle and increase the service life of the battery? Here are a few tips, please check them out:
- If possible, choose slow charging. If you use fast charging for a long time, it will greatly damage the battery performance.
- Control the charging time. Generally, the battery charging time should last about 10 hours, and the preferable charging timing is when the battery capacity is 20%-90%.
- Do not expose the electric vehicle to the sun for a long time. It is easy to cause damage and aging of the battery plates under high temperature and low temperature conditions.
- Avoid slamming on the accelerator pedal when starting the vehicle or having a manned uphill.
- Try to avoid wading.