Why is the performance of lithium batteries degraded?

On the one hand, the performance degradation of lithium batteries is a natural result of use and aging, and on the other hand, it is accelerated due to lack of maintenance, harsh use environments, and poor charging operations. 1. High self-discharge rate Various batteries have self-discharge, but improper use will promote the development of this state. The self-discharge rate is an asymptotic law, and the highest discharge rate is just after charging, and then gradually decreases. The percentage of battery self-discharge can be measured with a battery disintegrator, but this procedure takes several hours. The measured internal resistance of the battery can often reflect whether the internal resistance of the battery is too high. This parameter can be measured with an impedance meter or with the ohm detection program of a battery disintegrator. 2. The matching of the battery In a battery pack composed of multiple batteries, the matching of the battery should be controlled within ±2.5%. In battery packs with a large number of batteries, as well as battery packs that need to output large load currents and work at low temperatures, stricter tolerance control of lithium batteries is required. If each battery in a new battery pack has a slight mismatch, after several charging cycles, they will be able to balance each other and adapt themselves. Whether the batteries can be well balanced and adapted is related to whether the battery pack has a long service life. High-quality batteries are more consistent and more balanced than low-quality lithium batteries. High-quality batteries should be used for high-end high-power tools, because they have high durability under heavy loads and extreme temperature environments. Despite the high cost, the reward is that the battery pack has a longer life. 3. Short-circuited batteries Lithium battery manufacturers often cannot explain why certain batteries show high leakage rates or electrical short circuits when the batteries are still in a relatively new state. The suspicious reason is that foreign particles and impurities may have been mixed into the battery during the manufacturing process. The other is that rough spots on the electrode cause damage to the diaphragm. Therefore, the manufacturing process of the battery should be improved, which can greatly reduce the early failure rate of the battery. The polarity reversal of the lithium battery caused by deep discharge can also cause the battery to short circuit. If the nickel-based battery is discharged at a large current to completely discharge, this state may also appear. A high reverse current can cause a permanent electrical short circuit. Another reason is the damage of the diaphragm caused by the formation of an uncontrollable lens, which is the so-called memory effect. 4. Loss of electrolyte Although lithium batteries are sealed, some electrolyte will be lost during their service life, especially if excessive gas pressure occurs due to careless and improper charging, resulting in gas emissions. Once gas discharge occurs, the spring-loaded exhaust gasket on the nickel-based battery may be difficult to close again, causing white powder to be deposited around the gasket, and the loss of electrolyte will eventually reduce the capacity of the lithium battery. 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 article: Brief description of charging methods for lead-acid batteries and lithium batteries