But no matter what kind of battery, there is actually a chemical reaction, and only when there is a chemical reaction will there be energy gain or loss. Therefore, when buying a new battery, the materials used in it are generally in the best state, with good sealing and good heat dissipation. Long-term use will produce a lot of "garbage" inside the battery, which will further affect the energy gain and loss in chemical reactions, that is, generate more heat energy. Moreover, the material at this time has been corroded and deteriorated to varying degrees, which will make its heat dissipation performance worse.

Therefore, after a long period of use or even a new battery just bought (due to design and material problems, or storage methods before reaching users, or even futures), the battery may be charged and heated.