As a result of the popularity of lithium battery, a lot of electric cars on the market use lithium battery now, this also makes the accident that lithium battery explosion causes casualty to happen from time to time, the cause of the explosion of the lithium battery is popularized today First, the lithium battery negative capacity is insufficient When the capacity of the negative electrode portion of the positive electrode portion of the lithium battery is insufficient, lithium atoms generated during charging cannot be inserted into the interlayer structure of the negative electrode graphite, and are deposited on the surface of the negative electrode to form crystals.