What causes the Panasonic battery to leak?
Panasonic battery will leak during use, so do you know what causes Panasonic battery to leak? Here is a detailed introduction:
The heat seal is to heat the ABS shell to a certain temperature (at this time, it has certain activity and cohesiveness), and fill it into the gap between the Panasonic battery shell and the cover. Because of this method, the shell and cover are injected into a whole, and the shell and cover bonding department are all ABS materials, the heat seal has high sealing reliability and can effectively solve the problem of leakage between the shell and cover.
The Panasonic battery sealed by epoxy resin adhesive leaks a lot of liquid. If the epoxy resin formula and curing premise are well controlled, the sealing can be realized. Through the analysis of the Panasonic battery with epoxy resin adhesive seal leakage, it is found that the leakage of the Panasonic battery sealant and the shell are bonded at the interface, and the joint effort is not great, so it is easy to fall off, and the leakage is lack of glue holes or cracks. Because of the poor activity of epoxy resin adhesive (especially low temperature curing), it is easy to cause that some parts of the sealing shell cover are not filled with adhesive, resulting in leakage channel.
Panasonic batteries produced at home and abroad have leakage problems to varying degrees, mainly due to pole leakage and poor sealing of Panasonic battery cover. There are two sealing methods for the cover of Panasonic battery shell: glue sealing and heat sealing. The sealing method is to seal the shell and cover with epoxy resin glue. The sealing quality is affected by the function of epoxy resin glue. The aging and cracking of epoxy resin are the main problems that cause the leakage of Panasonic battery.
In the production process, many Panasonic batteries are in the state of rich liquid after being filled with acid, and there is no oxygen cycle in Panasonic batteries. Depending on the battery in the starting state of three charges and two discharges, the excess electrolyte is discharged, and the sulfuric acid density is improved again. When the safety valve is covered, the electrolyte does not absorb light and there is free acid. When the free acid is absorbed in time, the battery is still in the "quasi lean liquid" state. There is more electrolyte in the separator. However, a little more electrolyte in the separator affects the oxygen cycle, so when charging the new battery, the exhaust volume is relatively large and the sulfuric acid brought out is relatively large. Forming "acid leakage". In the first 50-100 cycles of the double deck battery, the battery is in the transition period from rich liquid to poor liquid, and the exhaust gas is severe. The colloidal particles from the exhaust gas form the "acid leakage".
For the Panasonic battery with leakage, visual inspection shall be carried out first to find out the leakage part. Remove the cover plate to see if there is any trace of acid leakage near the safety valve, and then open the safety valve to see if there is any active electrolyte inside the Panasonic battery. After the above work is completed, if no abnormality is found, the air tightness test shall be carried out (put the water to inflate and pressurize, observe whether there is bubble generated and emerging from the battery, and if there is bubble, it means there is acid leakage). Finally, during the charging process, observe whether there is active electrolyte. If there is, it indicates the reason for production. If there is any active electrolyte during the charging process, it should be pumped out.
In addition to the mechanical damage caused by transportation and handling, the leakage fault of Panasonic battery is mainly caused by manufacturing defects, such as too much electrolyte injection, loose sealing, different sealing materials and aging sealing materials. In the manufacturing process of battery, some manufacturers apply silicon oil near the pole to enhance the sealing function of battery shell, so there may be non acid liquid exudation near the pole in use. This is a normal phenomenon, not a leakage, we should pay attention to distinguish.