Why are lithium iron phosphate batteries bulging?

The reason for the bulging of lithium iron phosphate battery: 1. Overcharge of the lithium battery caused by overcharging will cause all the lithium atoms in the positive electrode material to run into the negative electrode material, causing the original full grid of the positive electrode to deform and collapse. This is also a lithium iron phosphate battery An important reason for the decrease in group power. In this process, there are more and more lithium ions in the negative electrode, and the excessive accumulation makes the lithium atoms grow out of the tree stump crystals, which makes the lithium battery pack swell. 2. Bulging caused by over-discharge During the first charge and discharge of a liquid lithium battery, the electrode material and the electrolyte react at the solid-liquid interface to form a passivation layer covering the surface of the electrode material. The formed passivation film can effectively prevent the passage of electrolyte molecules, but Li+ can be freely inserted and extracted through the passivation layer, which has the characteristics of a solid electrolyte, so this passivation film is called SEI. The SEI film is not static, there will be a little change during the charge and discharge process, the important thing is that some organic matter will undergo reversible changes. The over-discharge of the lithium iron phosphate battery causes the SEI film to be reversibly broken, and the destruction of the SEI protecting the negative electrode material causes the negative electrode material to collapse, thereby forming a bulging phenomenon. 3. The problem of manufacturing level Lithium battery bulge may be a problem of the manufacturing level of lithium iron phosphate battery pack, the electrode coating is not uniform, and the processing technology is relatively rough. Four. The bulging phenomenon of the lithium iron phosphate battery pack will also occur if it is not used for a long time, because the air is conductive to a certain extent, so if the battery is left for too long, it is equivalent to the direct contact of the positive and negative electrodes of the battery and a chronic short circuit . Disclaimer: Some pictures and content of articles published on this site are from the Internet. If there is any infringement, please contact to delete.