Because of the accident that the lithium battery exploded and caused casualties, the cause of the explosion of the lithium battery is popularized today.
Due to the popularity of lithium batteries, many electric vehicles on the market now use lithium batteries, which also causes accidents in which lithium batteries explode and cause casualties. This is because of what caused it. Today, I will give you a good science.
First, the lithium battery negative capacity is insufficient
When the capacity of the negative electrode portion of the positive electrode of the lithium battery is insufficient, the lithium atoms generated during charging cannot be inserted into the interlayer structure of the negative electrode graphite, and will be deposited on the surface of the negative electrode to form crystals.
Long-term crystallization in a lithium battery can cause a short circuit. At this time, the battery is discharged abruptly, and a large amount of heat is generated, which burns the diaphragm. The high temperature decomposes the electrolyte into a gas. When the pressure is too high, the battery will explode.
Second, the moisture content is too high
When charging, water can react with lithium to form lithium oxide, which causes the capacity of the cell to be lost. It is easy to overcharge the cell and generate gas. The decomposition voltage of water is low, and it is easy to decompose and generate gas when charging. A series of generated gases will increase the internal pressure of the cell, and the cell will explode when the cell's outer casing cannot withstand it.
Third, internal short circuit
The short circuit of the internal battery causes a large current discharge, generates a large amount of heat, burns the diaphragm, and causes a larger short circuit, which will decompose the electrolyte into a gas. If the internal pressure is too large, the battery will explode.
Fourth, lithium battery overcharge
When the battery cell is overcharged, the lithium of the positive electrode is excessively released, which causes the structure of the positive electrode to change. However, too much lithium is released, and it is easy to insert into the negative electrode, and it is easy to cause lithium deposition on the surface of the negative electrode. Moreover, when the voltage reaches 4.5V or higher, The electrolyte will decompose to produce a large amount of gas. All of the above may cause an explosion.
Five, external short circuit
The external short circuit may be caused by the wrong connection between the positive and negative poles. Due to the external short circuit, the battery discharge current is very large, which will cause the heat of the battery core. The high temperature will cause the diaphragm inside the battery core to shrink or completely deteriorate, causing an internal short circuit and thus exploding.
