What are the reasons for the swelling of lithium batteries

One. Overcharge 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, which is also an important reason for the decline in the power of the lithium battery pack. In this process, there are more and more lithium ions in the negative electrode, and the excessive accumulation causes the lithium atoms to grow out of the tree stump crystals, which makes the lithium battery pack swell. two. The bulging SEI film caused by over-discharge will have a protective effect on the negative electrode material, so that the material structure is not easy to collapse, and the cycle life of the electrode material can be increased. The SEI film is not static, there will be a little change during the charging and discharging process, the most important thing is that some organic matter will undergo reversible changes. After the lithium battery pack is over-discharged, the SEI film will be reversibly broken, and the SEI protecting the negative electrode material will collapse after the destruction of the negative electrode material, thereby forming a bulging phenomenon. 3. The charger parameters do not match the required parameters of the lithium battery pack. This may be due to the original discrepancy or parameter drift caused by the use process. Fourth, the battery vulcanization battery is mainly caused by vulcanization, the main reason for causing vulcanization is high current discharge, unable to charge in time, deep discharge, frequent discharge, too short charging time, factors caused by the charger itself, etc. 5. Safety valve Electric vehicle batteries have a safety valve. When the pressure in the lithium battery pack of an electric vehicle rises, the safety valve is automatically opened to release the pressure, so that the normal use of the battery can be ensured. When the pressure of the battery rises, but the safety valve cannot be opened, a bulging situation will occur. 6. Long-term idle In addition, the lithium battery pack will also be bulging if it is not used for a long time, because the air is conductive to a certain extent, therefore, if the battery is left for too long, it is equivalent to direct contact between the positive and negative electrodes of the battery Chronic short circuit. 7. The manufacturer's production problems The production environment is bad, the production equipment is old, etc., so that the coating of the battery is uneven, and dust particles are mixed in the electrolyte. All of these may make the lithium battery pack bulge when used by the user, and even cause greater danger. 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: Is the instability of lithium batteries the cause of electrolyte?