Recently, Mao Huanyu, the Chief Technology Officer of BAK Battery Co., Ltd., admitted that the hidden dangers of lithium batteries catching fire, burning, or even exploding still cannot be completely eliminated. Causes such as collisions leading to the breach of the battery's separator by the positive and negative electrode materials, or the extremely high current when energy is rapidly recharged into the battery during braking (the current during energy recovery while braking in electric vehicles can reach 250-300 amperes, and if this excessive current is not properly diverted, it can easily cause a short circuit), can lead to short circuits, increased temperature, and ultimately result in fires or explosions.
Additionally, the electrolyte of lithium-ion batteries is an organic electrolyte, which is more prone to ignition and combustion when exposed to air.
Li Gechen, General Manager of Science Energy Technology, made a comparison between gasoline and lithium batteries:
From a working principle perspective, a tank of gasoline is safer than a lithium battery. Gasoline is stored in a fuel tank and is safe as long as there is no external oxygen or open flame; however, this is not the case with lithium batteries. The energy in a lithium battery is stored between the positive and negative electrodes, which are immersed in a flammable electrolyte solution. The only thing separating the electrodes is a 20-micron thick separator. Without any external conditions, the internal structure of the battery itself provides the conditions for the release of energy from the positive and negative electrodes, generating heat and potentially causing a fire.
The probability of safety issues with power batteries is between one in one million to one in ten million. When the number of electric vehicles is small, this probability may seem negligible, but as the number of vehicles increases, the risks rise. Moreover, as the battery ages over time, its safety diminishes. One of the challenges for companies is that it is difficult to verify the safety of the battery with a few test vehicles and a few tens of thousands of kilometers of testing for an issue that happens with such a small probability.
In the process of promoting new energy vehicles, if power batteries frequently experience safety incidents, it will undoubtedly have a huge negative impact on the promotion of electric vehicles.