Sometimes, although the battery itself has safety control measures, if the control fails due to some reasons, and the safety valve or gas is not enough to be released through the safety valve, the internal pressure of the battery will rise sharply and cause an explosion.
Under normal circumstances, the total energy stored in a lithium-ion battery is inversely proportional to its safety. As the battery capacity increases, the battery volume also increases, and its heat dissipation performance deteriorates, and the possibility of an accident increases greatly. For lithium-ion batteries for mobile phones, the basic requirement is that the probability of a safety accident is less than one in a million, which is the minimum standard acceptable to the public. For large-capacity lithium-ion batteries, especially for large-capacity lithium-ion batteries such as automobiles, it is especially important to use forced cooling.