Analysis of Causes of battery Safety Failure

Studying the failure mode of the battery pack system is of great significance for improving the battery life, improving the safety and reliability of application products, and reducing the cost of application products.

Battery failure modes can be divided into safe failure modes and non-safety failure modes. The safety failure of the battery mainly includes the following points:

1. The positive and negative terminals of the battery cell are shorted:

The short circuit of the battery is caused by the inside of the battery. There are many reasons for battery short circuits, which may be caused by defects in the production process of battery cells or deformation of battery cells caused by long-term vibration external forces. If a severe internal short circuit occurs, control will not be avoided, the external fuse will not work properly, and it will definitely smoke or burn.

Therefore, it is very important to paste the insulation paper on the battery before assembling the battery pack. Choosing a good battery insulation paper sticking machine is the key.

2. Battery cell leakage:

This is very dangerous and a very common failure mode. Battery leakage may be caused by external forces; improper collision or installation will damage the sealing structure; manufacturing reasons: poor welding performance due to welding defects or insufficient sealant.

3. Lithium evolution of battery negative electrode:

Improper use of the battery, overcharging, low temperature charging and high current charging will cause the lithium anode of the battery to precipitate. After the anode lithium is discharged, lithium metal cannot be reduced, which causes the battery capacity to irreversibly decay. The lithium analysis reached a certain degree of severity, forming lithium dendritic crystals, and an internal short circuit occurred when the diaphragm was punctured.

4. The battery becomes bloated:

There are many reasons for gas expansion, mainly due to side reactions inside the battery, most typically side reactions with water. Flatness can be avoided by strictly controlling the moisture in the battery production process. Leakage occurs when the battery is exhausted.