What are the main causes of lithium battery explosions?

Lithium batteries explode, a perception many people have when talking about lithium-ion batteries. In recent years, many news have reported on lithium battery safety issues. So why do lithium batteries explode? What are the main causes of lithium battery explosions?

The following summarizes ten reasons why batteries explode:

1. There is too much positive electrode during design, or the coating is uneven. Vibration during transportation causes the pole piece to be misaligned, and lithium dendrites appear during charging.

2. Vibration during transportation causes the pole pieces to be dislocated, causing a short circuit through the shell or connecting piece when the electrode expands.

3. Burrs and dust, vibration and expansion cause the diaphragm to short circuit.

4. Excessive power during welding may damage the internal outer diaphragm or increase metal dust.

5. The voltage and temperature during transportation cause instability of the SEI layer.

6. Overcharging. When the battery cell is overcharged, the excessive release of lithium from the positive electrode will cause the structure of the positive electrode to change. Too much released lithium will easily fail to be inserted into the negative electrode, and it will also easily cause lithium precipitation on the surface of the negative electrode. Moreover, when the voltage reaches overcharge voltage, The electrolyte will decompose to produce a large amount of gas

7. The moisture content is too high. Moisture can react with the electrolyte in the battery core to produce gas. During charging, it can react with the generated lithium to generate lithium oxide, which will cause the capacity of the battery core to be lost. It is easy to overcharge the battery core and generate gas. The decomposition of water The voltage is low and it is easy to decompose to generate gas during charging. When this series of generated gases increases the internal pressure of the battery core, when the outer shell of the battery core cannot withstand it, the battery core will explode.

8. The negative electrode capacity is insufficient. When the capacity of the negative electrode opposite the positive electrode is insufficient, or has no capacity at all, part or all of the lithium produced during charging cannot be inserted into the interlayer structure of the negative electrode graphite, and will precipitate on the surface of the negative electrode, forming protruding "branches" When charging next time, this protruding part is more likely to cause the precipitation of lithium. After dozens to hundreds of cycles of charge and discharge, the "dendrites" will grow and eventually pierce the separator paper, causing an internal short circuit. .

9. Internal short circuit. Due to the internal short circuit phenomenon, the battery core is discharged with a large current, generating a large amount of heat, burning the diaphragm, and causing a larger short circuit phenomenon. In this way, the battery core will generate high temperature, causing the electrolyte to decompose into gas, causing excessive internal pressure. When the outer casing of the battery core cannot withstand this pressure, the battery core will explode.

10. External short circuit. External short circuit may be caused by improper operation or misuse. Due to external short circuit, the battery discharge current is very large, which will cause the battery core to heat up. The high temperature will cause the diaphragm inside the battery core to shrink or be completely damaged, causing an internal short circuit and thus explosion. .

All of the above are the reasons for the explosion of lithium battery packs. Of course, there are many factors that affect the safety of lithium batteries, such as the use of inferior batteries, irregular packaging processes, improper use by users, etc., which will cause certain safety problems. I hope relevant practitioners will improve Technology and detection capabilities. Users should also pay attention during use. Of course, the more important thing is to choose reliable lithium battery products and suppliers. Solid-state batteries will be a good choice. The liquid electrolyte, the source of battery fires, is replaced by solid-state batteries to eliminate battery safety hazards from the source. It can pass acupuncture tests and will not catch fire or explode