Analyze the cause and solution of polymer lithium battery bulge

Reasons for the bulging of polymer lithium battery 1. The polymer battery cell is overcharged. As mentioned above, when the battery cell voltage exceeds 4.2V, there should be a series of chemical reactions inside the gas, which will be repeated for a long time. Slightly overcharged, the gas inside the cell gradually accumulates and swells the cell. Therefore, we must ensure that the battery core cannot be overcharged during use and testing. When designing the charging circuit and the protection board, full consideration should be given to the charging voltage not to exceed 4.2V. 2. The cell is over-discharged. When the cell is over-discharged (voltage<2.0V) and stored for a long time, due to the electrolysis reaction inside the cell, the copper in the anode current collector decomposes, and gas appears inside the cell. The important reaction process of the gas is as follows: 3. The polymer cell is affected by high temperature, and the cell is inflated in a high temperature environment as listed above. Most of the time, the cell is stored at a higher temperature (such as 50C) for a long time. The temperature will accelerate some chemical reactions inside the cell, forming gas, especially when the cell is fully charged or slightly overcharged, the effect of high-temperature storage is more obvious. Therefore, the cell should be prevented from being exposed to high temperatures for a long time. storage. 4. The gas that appears in the battery cell within the normal working voltage range. When the battery cell is just made, we will perform several cycles of charging and discharging to make a layer of compound on the surface of the electrode to protect the pole piece and It will no longer participate in the reaction in the future charge and discharge process. 5. The polymer lithium battery cell is stored for a long time when it is fully charged or overcharged. When the cell is fully charged or slightly overcharged, the inside of the cell is not damaged at this time. Because Li atoms are very active and have extremely strong reducibility, at this time the Li+ of the anode is pulled out to the maximum, which is extremely oxidizing. It is possible that Co3O4 can slowly react with trace substances in the electrolyte and produce gas. Therefore, if the battery cell is fully charged or overcharged, if it is stored for a long time, some cells will have a slight swelling phenomenon. In addition, when the sealing of the battery cell packaging material is damaged, water molecules in the air enter the battery cell, which will also cause serious swelling inside the battery cell. The correct approach to polymer lithium batteries is summed up. The most important tips for charging and discharging lithium battery packs in use are 1. Charge according to the standard time and procedure, even the first three times; 2. When the machine appears When the battery is too low, you should start charging as soon as possible; 3. There is no special way to activate the lithium battery. The lithium battery will naturally activate during the normal use of the machine. If you insist on using the first three 12-hour long charge activation methods that have been circulated, it will actually not be effective; 4. If you have multiple polymer lithium battery packs that are swollen, it should be the cut-off voltage of the charger you use If it does not match the battery, it is recommended to replace it; 5. If the spare polymer lithium battery is not used for a long time, it is recommended not to fully charge it for storage, it is best to retain about 60% of the power. The solution to the bulge of the polymer lithium battery 1. If the mobile phone battery has been charged up, use your fingers to find the gap in the battery first, and poke a small hole with the needle to let the air out of it. 2. You can purchase a new polymer lithium battery pack to replace it. During the charging process, overcharging should be prevented, which not only protects the battery from damage, but also saves energy and protects the environment. How can manufacturers reduce the swelling of polymer lithium batteries? The end product manufacturer should also consider the battery swelling rate of about 0.1% when designing the product. After the polymer lithium charge and discharge cycle, there will be a certain percentage of swelling, but it will not affect the use, product performance and safety, and will not bulge. . Disclaimer: Some pictures and content of the articles published on this site are from the Internet. If there is any infringement, please contact to delete it. Previous post: Do you know the general correct use of lithium batteries?