What is the cause of the lithium battery fire in electric vehicles?

At present, all kinds of consumer electronics, mobile power supplies, new energy vehicles, etc. represented by mobile phones use lithium battery equipment. Lithium batteries are the future direction of new energy development. Recently, some electronics factories have frequently caught fire and exploded. The safety of lithium batteries has become the most concerned issue for consumers.

Here are five reasons why electric vehicle lithium batteries catch fire:

1. External short circuit

External short circuits can be caused by improper operation or misuse. Due to the external short circuit, the discharge current of the battery is very large, which will cause the cell to heat up. .

2. Internal short circuit

Due to the internal short circuit phenomenon, the high current discharge of the cell will generate a lot of heat, burn the diaphragm, and cause a large short circuit phenomenon. In this way, the cell will generate high temperature, the electrolyte will be decomposed into gas, and the internal pressure will be too large. When the battery's casing can't handle this pressure, the battery catches fire.

3. Overcharging

When the battery is overcharged, too much lithium released from the positive electrode will change the structure of the positive electrode. If too much lithium is released, it is easy to fail to embed the negative electrode, and it is easy to precipitate lithium on the surface of the negative electrode. The electrolyte will decompose and generate a large amount of gas. All of the above may cause fire.

4. The water content is too high

Water can react with the electrolyte in the battery to produce gas. When charging, it reacts with the generated lithium to form lithium oxide, which will cause the loss of cell capacity, and it is easy to overcharge to generate gas and decompose water. The voltage is low, and it is easy to decompose and generate gas when charging. When the gas generated by this series will increase the internal pressure of the battery cell, when the battery cell shell cannot withstand it, the battery core will explode.

5. Insufficient negative electrode capacity

When the capacity of the negative electrode opposite to the positive electrode is insufficient, or has no capacity at all, some or all of the lithium generated during charging cannot be embedded in the interlayer structure of the negative electrode graphite, and the negative electrode will precipitate on the surface to form a protruding "branch". In the subsequent charging process, this protruding part is more likely to lead to the precipitation of lithium. After dozens to hundreds of charge-discharge cycles, the "dendrite" will grow, and Z will pierce the separator paper, causing an internal short circuit.

How to make lithium-ion batteries safer?

 1. Don't try to modify the battery

 2. Do not overcharge or overdischarge when charging.

3. Use the original charger.

4. Use a reliable battery

5. Do not place the battery in extreme environments (except for some special batteries). High temperature, collision, etc. are all important causes of battery explosion. Try to place the battery in a stable environment away from high temperature places.