These lithium metal crystals pass through the diaphragm paper to short-circuit the positive and negative poles. Sometimes in the short circuit before the battery exploded, this is because in the overcharge process, electrolyte and other materials will be cracked to produce gas, so that the battery shell or pressure valve drum burst, so that oxygen into the negative surface with the accumulation of lithium atom reaction, and then exploded. Therefore, lithium battery charging, must set the voltage limit, can take into account the battery life, capacity, and security. The ideal charge voltage limit is 4.2V. Lithium battery Core discharge should also have the lower voltage. When the voltage of the core is below 2.4V, some of the material will begin to be destroyed.