The cause of bulge in polymer lithium-ion batteries
1, polymer cell is overcharged, as mentioned above, when the voltage of the cell exceeds 4.2V, the internal gas will appear for a series of chemical reactions, many times for a long time slightly overcharged, the gas inside the cell gradually agglomerate and make the cell bulge. Therefore, we must ensure that the battery can not be overcharged in the process of use and testing, and the charging voltage should not exceed 4.2V when designing the charging circuit and the protection plate.
2, the cell is over discharge, when the cell is over discharge (voltage <2.0V) and is stored for a long time, due to the electrolysis reaction inside the cell, the anode collection of fluid copper decomposition, gas, and the gas inside the cell, its important reaction process is as follows:
3, polymer batteries are influenced by high temperature, batteries under the environment of high temperature and strengthening situation such as listed above, most of the time, the batteries at high temperature (such as 50 c) storage for a long time, the temperature will accelerate the batteries inside some of the chemical reaction, the formation of gas, especially the batteries in the case of filled or slight overcharge, the effect of the high temperature storage effect is more apparent, Therefore, the cell should be prevented from long-term storage at high temperature.
4, the cell in the normal working voltage range of gas, when the cell just made, we will carry out several cycles of charging and discharging, so that the surface of the electrode appears a layer of compound layer, to protect the electrode piece, and in the future in the process of charging and discharging no longer participate in the reaction.
5. The polymer lithium cell is stored for a long time under the condition of full or overcharge. When batteries are filled or slight overcharge, the batteries inside is not damaged, because of Li atoms is very lively, strong reducibility, while Li + anode are pulled out to maximize, have strong oxidizing the possibility of Co3O4, can slowly reaction with the electrolyte in the trace material, gas, so the batteries in filled or overcharge cases, have been stored for a long time, Some cells will appear a slight bulging phenomenon. In addition, when the seal of the cell packaging material is damaged, water molecules in the air enter the inside of the cell, which will also cause serious bulging inside the cell.
Correct practice of polymer lithium ion battery
To sum up, the most important tip for lithium-ion battery pack charge and discharge problems in use is
1, in accordance with the standard time and program charging, even if it is the first three times also want to do so;
2, when the machine is too low power prompt, should try to start charging in time;
3. There is no special method to activate the lithium ion battery. The lithium ion battery will be activated naturally during the normal use of the machine. If you insist on using the first three 12 hours of circulating long charge activation method, actually also won't have the effect;
4. If you have multiple polymer lithium-ion battery packs, it should be because the cut-off voltage of the charger you use does not match the battery, so it is recommended to replace it.
5. If the spare polymer lithium ion battery is not used for a long time, it is recommended not to save it with full charge. It is best to retain about 60% of the power.
Polymer lithium ion battery bulge solution
1. If the cell phone battery has been charged, use your finger to find the gap in the battery and poke a small hole with the finger to let the air out.
2. A new polymer lithium ion battery pack can be purchased to replace it. In the process of charging, overcharging should be prevented, which can not only protect the battery from damage, but also save energy and environmental protection.
How can manufacturers reduce bulging of polymer lithium-ion batteries?
The end product manufacturer should also consider the battery bulging rate of about 0.1% when designing the product. There will be a certain percentage of bulging after the charge and discharge cycle of lithium polymer, but it will not affect the use, product performance and safety, let alone bulging.
