What kinds of changes are there for long-term storage of lithium batteries?

According to the actual proof after the time storage of the lithium battery, the physical characteristics (appearance, size, weight, etc.) of the battery will undergo certain changes, especially the appearance characteristics. This trend of change is more obvious when the temperature and humidity of the storage environment are not good. In the case of high humidity, after long-term storage of lithium batteries, the increase in importance is significantly higher than that of batteries placed in low humidity conditions. For example, the steel shell part of the battery is prone to rust when the humidity is high, resulting in a slight increase in quality. Rust will not affect the internal state of the battery, but it will directly affect the shipment of the product and may have a negative impact on the electronic components that match it. 2. Electrochemical characteristics: Long-term storage of lithium batteries will have some side reactions, such as electrolyte analysis, active material dissolution, lithium deposition, etc. After being left for a long time, the internal balance of the lithium battery gradually changes. When it accumulates to a certain extent, the battery will undergo more obvious changes, which will be directly reflected in the electrochemical characteristics of the battery. 1) The capacity changes of lithium batteries that have been put on hold for a long time are critically reflected in two points: one is the decrease in battery capacity, which is mainly caused by self-discharge; the other is the increase in irreversible capacity, which is critically dependent on the irreversible consumption reaction between the internal chemical system of the battery . The self-discharge phenomenon is unprepared in all lithium batteries. The capacity loss caused by self-discharge can be divided into two types: reversible and irreversible: reversible refers to the part of the capacity that can be restored when charging the lithium battery, and irreversible loss refers to the capacity that cannot be restored. For battery manufacturers and battery users, it is necessary to reduce battery capacity loss after long-term storage. 2) Internal resistance The internal resistance of a battery refers to the resistance between the positive and negative ends, which is the sum of the resistance of the current collector, electrode active material, diaphragm, electrolyte, conductive handle, and terminal. For lithium batteries, the smaller the internal resistance, the smaller the voltage occupied by the battery when it is discharged, and the more energy it can output. But for long-term storage batteries, the resistance tends to increase as the storage time increases. Exceeding a certain resistance will cause the internal battery to exceed the benchmark and be scrapped or degraded. Therefore, it is necessary to pay attention to the resistance change of the battery during long-term storage. Temperature has a greater effect on internal resistance: at 25°C, the lithium battery is stored for 32 days, and the internal resistance changes to 0.57mQ; at 50°C, the battery is stored for 1 month, and the internal resistance is increased by 2.64m; when the ambient temperature reaches 75C , The battery resistance changes rapidly. After being left for the same number of days, the new resistance value is 8.18m, which is 14 times that at 25°C. 3) Discharge characteristics The discharge characteristics of lithium batteries show a downward trend after long-term storage. The low temperature performance of batteries stored for a long time is significantly reduced. 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: Simple analysis of several lithium batteries