1. Physical micro-short circuit
Physical micro-short circuit is the direct cause of low voltage of lithium-ion battery. Its direct manifestation is that the battery voltage is lower than the normal cut-off voltage after the battery is stored at room temperature and high temperature for a period of time. Compared with the self-discharge caused by the chemical reaction, the self-discharge caused by the physical micro-short circuit will not cause the irreversible loss of the lithium-ion battery capacity.
2. Chemical reactions
2.1 Moisture causes the electrolyte to decompose, releasing a large amount of electrons, and the electrons are embedded in the positive electrode oxidation structure, which causes the positive electrode potential to drop, resulting in low pressure; The continuous corrosion of the SEI film will consume the lithium source and cause the low voltage of the battery.
2.2 Electrolyte solvent
The addition of some electrolyte solvents will cause the voltage of lithium-ion batteries to drop too quickly. Possible mechanism: These solvents are not resistant to oxidation, and slow chemical reactions occur during storage, which consumes capacity and causes the voltage to drop.
2.3 SEI film is not well formed
During the storage process, because the warehouse has a certain temperature, it will cause the SEI film to fall off and re-react, resulting in flatulence and low pressure of the lithium-ion battery.
2.4 Poor packaging
If the tab position is over-sealed, it may cause the tab to corrode and consume the low pressure of the lithium source; if the other position is over-sealed, the electrolyte may corrode the aluminum foil through the CPP layer, resulting in perforation of the aluminum-plastic film, and the entry of moisture to cause low-pressure flatulence.
3. Temperature
The higher the ambient temperature, the higher the activity of the electrochemical material of the lithium-ion battery, the more intense the side reactions involved in the positive electrode material, negative electrode material, electrolyte, etc. of the lithium power lithium battery, resulting in more capacity loss. The chemical self-discharge of lithium-ion batteries is more significant at high temperatures, and it is more effective to use high-temperature storage to judge the self-discharge of lithium-powered lithium batteries.
4. Electricity
By comparing the effect of lithium-ion battery charge on the self-discharge rate, the general trend is that the higher the lithium-ion battery charge, the higher the self-discharge rate. That is, the higher the charge level of the lithium-ion battery, the higher the positive electrode potential, and the lower the negative electrode potential.
