1. Excessive internal pressure. The lithium battery casing is not made of metal and is inherently soft, so it cannot be squeezed vigorously.

2. Unqualified external packaging. First, during the battery manufacturing process, if the following problems occur, battery leakage can easily occur:

1) When connecting the battery casing and cap, the weld is not secure and airtight, resulting in weld leaks, cold welds, cracks, and fissures in the weld seam.

2) When sealing with a steel ball, the ball is not the right size, or the material of the ball is different from that of the cap.

3) The positive terminal of the cap is not riveted tightly, with gaps, and the insulating gasket is not elastic enough, lacking corrosion resistance and prone to aging. Analysis of leakage problems in lithium-ion battery temperature tests [J], battery),

3. Problems that may occur during use

1) The battery is not original, the voltage is too high or the current is too large;

2) The battery is often bumped during normal use, damaging the aluminum-plastic film, and the internal strength of the battery is insufficient;

Using abnormal charging methods to cause overcharging, or high current rate discharge (damage to the battery’s high current protection system) Summarized from various forums and books As for scientific experiments, I will not go into details here~ (there are always ways to commit suicide)