中文
ENGLISHThe main causes of ignition in lithium-ion batteries
发布时间：2023-08-06 21:19:37 来源： 德国森泉蓄电池
The main causes of ignition in lithium-ion batteries
1、 External short circuit
External short circuits may be caused by improper operation or misuse. Due to external short circuits, the battery discharge current is high, which can cause the iron core to heat up. High temperatures can cause the diaphragm inside the iron core to contract or completely damage, causing internal short circuits and causing fires.
2、 Internal short circuit
Due to the internal short circuit phenomenon, the high current discharge of the battery cell generates a large amount of heat, burns out the membrane, and causes a large short circuit phenomenon, resulting in high temperature, causing the electrolyte to decompose into gas, resulting in excessive internal pressure. When the outer shell of the core cannot withstand this pressure, the core will catch fire.
3、 Overcharge
When the iron core is overcharged, the excessive release of lithium from the positive electrode will change the structure of the positive electrode. Excessive lithium is easily inserted into the negative electrode and can also cause lithium to precipitate on the surface of the negative electrode. When the voltage exceeds 4.5V, the electrolyte decomposes and produces a large amount of gas. All of these can cause a fire.
4、 Excessive moisture content
Water can react with electrolytes in the core to generate gas. When charging, it can react with the emerging lithium and produce Lithium oxide, which will cause loss of core capacity and easily lead to overcharge of the core and gas. The decomposition voltage of water is low, and it is easy to decompose into gas during charging. When these gases appear, the internal pressure of the core increases, and when the shell of the core cannot withstand these gases. At that time, the core will explode.
5、 Insufficient negative capacity
When the capacity of the negative electrode relative to the positive electrode is insufficient, or there is no capacity at all, some or all of the lithium that occurs during charging cannot be inserted into the interlayer structure of the negative electrode graphite, and will deposit on the surface of the negative electrode. The protruding dendrites are more likely to cause lithium precipitation in the next charge. After tens to hundreds of rounds of charging and discharging, dendrites will grow and eventually puncture the diaphragm, causing internal short circuits.
1、 External short circuit
External short circuits may be caused by improper operation or misuse. Due to external short circuits, the battery discharge current is high, which can cause the iron core to heat up. High temperatures can cause the diaphragm inside the iron core to contract or completely damage, causing internal short circuits and causing fires.
2、 Internal short circuit
Due to the internal short circuit phenomenon, the high current discharge of the battery cell generates a large amount of heat, burns out the membrane, and causes a large short circuit phenomenon, resulting in high temperature, causing the electrolyte to decompose into gas, resulting in excessive internal pressure. When the outer shell of the core cannot withstand this pressure, the core will catch fire.
3、 Overcharge
When the iron core is overcharged, the excessive release of lithium from the positive electrode will change the structure of the positive electrode. Excessive lithium is easily inserted into the negative electrode and can also cause lithium to precipitate on the surface of the negative electrode. When the voltage exceeds 4.5V, the electrolyte decomposes and produces a large amount of gas. All of these can cause a fire.
4、 Excessive moisture content
Water can react with electrolytes in the core to generate gas. When charging, it can react with the emerging lithium and produce Lithium oxide, which will cause loss of core capacity and easily lead to overcharge of the core and gas. The decomposition voltage of water is low, and it is easy to decompose into gas during charging. When these gases appear, the internal pressure of the core increases, and when the shell of the core cannot withstand these gases. At that time, the core will explode.
5、 Insufficient negative capacity
When the capacity of the negative electrode relative to the positive electrode is insufficient, or there is no capacity at all, some or all of the lithium that occurs during charging cannot be inserted into the interlayer structure of the negative electrode graphite, and will deposit on the surface of the negative electrode. The protruding dendrites are more likely to cause lithium precipitation in the next charge. After tens to hundreds of rounds of charging and discharging, dendrites will grow and eventually puncture the diaphragm, causing internal short circuits.
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