1. Internal short circuit (primarily large soft-packaged cells): Structural or process defects result in polar tabs being inserted, too little excess in the diaphragm housing, burrs, diaphragm discounts, etc. Tab insertion often occurs in thick batteries with internal parallel connections. Tab insulation is not in place. Adding protective plates on subsequent finished products or during use can easily lead to acute internal short circuits, resulting in combustion or explosion. However, this situation is almost rare now, unless there are external factors.
2. External Short: Post-combustion explosions caused by external shorts in batteries smaller than 1AH usually bulge or simply burn the tabs. A personal analysis was carried out on electric batteries orlarge size. Capacity batteries. Burn caused by external short circuit of mobile phone battery. This leads to improper use by customers: when installing the outer metal casing, the insulation of the tabs is not taken into account and the battery smokes and burns abnormally at the installation site. It is also common for power batteries to have insufficient (not well thought out) structural fixing measures; out), and when the user uses the battery, shaking may damage the external insulation protective film of the battery or damage the connection wires, possibly leading to short circuit and burn.
3. Overload Explosion: This is the most dangerous and the one that businesses fear the most, but it still happens occasionally. From what we know, there are two points: a. Users do not use the correct chargersnts as required, thereby destroying the protection circuit and users often charge without time limit. This situation is difficult without causing a battery explosion; unreasonable and the protection board fails, it will explode in a mess...the same goes for a single battery.
Since the negative electrode exists as a lithium-carbon compound (lithium-encrusted graphite) or lithium-silicon alloy, their chemical properties are very active. They react with water to generate hydrogen and at the same time. Releases a large amount of heat, causing the negative electrode to explode in the air and burn the hydrogen.
Lithium batteries are composed of positive and negative electrodes, electrolytes, separators and packaging materials. When a lithium battery is charged, lithium from the positive electrode flows to the negative electrode and is integratedin the sheets of the graphite negative electrode to form a lithium-carbon compound or form a lithium-silicon alloy with silicon.
Whether it is a lithium-carbon compound or a lithium-silicon alloy, they are very active chemicals and can react with water and oxygen. Reacting with water will violently release heat and release hydrogen, causing the pole piece to burn and hydrogen into the air.