Do you know what is the important reason for the explosion of lithium batteries?

When the capacity of the negative electrode part opposite to the positive part of the battery is insufficient, or there is no capacity at all, part or all of the lithium that appears when the lithium battery is charged cannot be inserted into the interlayer structure of the negative electrode graphite, and will precipitate on the surface of the negative electrode, forming protrusions. The protruding part is more likely to cause the precipitation of lithium during the next charge. After tens to hundreds of cycles of charging and discharging, the dendrites will grow up and eventually pierce the diaphragm paper, causing internal short circuits. The battery cell discharges rapidly, a large amount of heat occurs, which burns the diaphragm and causes a greater short-circuit phenomenon. High temperature will decompose the electrolyte into gas, and the negative carbon and diaphragm paper will burn, resulting in excessive internal pressure. When subjected to this pressure, the battery cell will explode. If the moisture content is too high, the moisture can react with the electrolyte in the battery cell and process gas. When charging, it can react with the generated lithium to generate lithium oxide, which will cause the capacity loss of the battery cell and easily cause the battery cell to be overcharged to generate gas. , The decomposition voltage of water is low, and it is easy to decompose to generate gas when charging. When this series of generated gas will increase the internal pressure of the battery, when the shell of the battery cannot withstand it, the battery will explode. Internal short circuit due to internal short circuit phenomenon, large current discharge of the battery cell, a large amount of heat occurs, burns the diaphragm, and causes a greater short circuit phenomenon, so that the battery core will have a high temperature, causing the electrolyte to decompose into gas, causing the internal pressure to be excessive. When the shell of the battery cell cannot withstand this pressure, the battery cell will explode. When the overcharge core is overcharged, the excessive release of lithium in the positive electrode will change the structure of the positive electrode. If too much lithium is released, it is easy to be unable to insert into the negative electrode, and it is also easy to cause lithium deposition on the surface of the negative electrode, and when the voltage reaches 4.5V or more , The electrolyte will decompose and process a large amount of gas. All of the above may cause an explosion. External short-circuit The external short-circuit may be caused by improper operation or misuse. Due to the external short-circuit, the battery discharge current is large, which will cause the battery core to heat up, and the high temperature will shrink or completely damage the diaphragm inside the battery cell, causing an internal short circuit. explosion. Disclaimer: Some pictures and content of articles published on this site are from the Internet. If there is any infringement, please contact to delete. Previous: What are the important maintenance methods for lithium battery packs in summer?