I. Introduction
The existence of self-discharge phenomenon of lithium battery has become an important factor restricting its performance and life. In this paper, the principle, influencing factors and countermeasures of lithium battery self-discharge are discussed.

Second, the principle of lithium battery self-discharge

Self-discharge refers to the phenomenon that the battery capacity automatically loses when it is not charged and discharged. For lithium batteries, self-discharge is mainly manifested as the oxidation reaction of negative lithium ions, resulting in the irreversible embedding of lithium ions into the positive material. This process is accompanied by the transfer of electrons, which reduces the potential of the battery and ultimately leads to a reduction in the battery capacity.

Third, the factors affecting the self-discharge of lithium batteries

1. Positive and negative electrode materials: The choice of positive electrode materials has a significant impact on the self-discharge of lithium batteries. In general, the presence of transition metal elements in positive materials increases the rate of self-discharge. The structure and properties of the anode material also affect the self-discharge performance, such as graphite layer spacing and particle size.
2. Electrolyte composition: The composition of electrolyte has an important impact on the self-discharge behavior of lithium batteries. The decomposition reaction of the electrolyte and the passivation on the electrode surface can lead to self-discharge. In addition, the electrochemical stability and flash point of the electrolyte also affect the self-discharge performance.
3. Temperature: Temperature is an important factor affecting the self-discharge of lithium batteries. At high temperature, the reactivity of electrode material increases and the self-discharge reaction is accelerated. At the same time, high temperature will also affect the physical and chemical properties of the electrolyte, and further affect the self-discharge performance.
4. Storage time and state of charge: The self-discharge rate of lithium battery accelerates with the increase of storage time, and the state of charge will also have an impact on self-discharge. In general, the higher the state of charge of the lithium battery, the faster its self-discharge rate.
Battery self-discharge is a complex physical and chemical process, which involves many factors, including battery manufacturing process, material type, environmental conditions and so on. In the actual production, the self-discharge of the battery shows a certain regularity of time. The following is the regularity of the self-discharge of the battery in actual production. Different systems of battery shelving time is different, low voltage detection of bad peak value is different

Fourth, reduce the self-discharge strategy of lithium batteries

1. Positive electrode material modification: By adjusting the composition and structure of the positive electrode material, the self-discharge rate of the lithium battery can be reduced. For example, by adding certain elements to stabilize the structure of the positive electrode material, or by adopting a high-capacity positive electrode material to reduce the amount of lithium ion embedding.
2. Anode material optimization: Improving the structure and properties of anode materials can effectively reduce the self-discharge of lithium batteries. For example, the choice of graphite materials with large layer spacing, or the use of nanostructured anode materials to improve the storage capacity of lithium ions.
3. Electrolyte selection and modification: Choosing an electrolyte with high electrochemical stability and low reactivity is an effective way to reduce the self-discharge of lithium batteries. In addition, the electrolyte can be modified by adding electrolyte salts or other additives to reduce its decomposition and passivation on the electrode surface.
4. Battery management system: The use of advanced battery management system (BMS) can effectively monitor and manage the working state and charge state of lithium batteries, thereby reducing the self-discharge rate. BMS can monitor the battery's voltage, current, temperature and other parameters in real time, and adjust the working state and charge state of the battery according to these parameters to extend the service life of the battery.
5. Storage condition control: Proper storage conditions are very important to reduce the self-discharge of lithium batteries. Storing the battery under the right temperature and humidity conditions can slow down the progress of the electrode reaction, thus reducing the self-discharge rate. In addition, regular charging and discharging cycles of the battery can also effectively alleviate the phenomenon of self-discharge.
6. New structures and materials: With the continuous development of science and technology, new battery structures and materials continue to emerge. For example, solid-state lithium batteries have higher safety, energy density and cycle life because they use solid-state electrolytes instead of traditional liquid electrolytes. In addition, new battery systems such as lithium-sulfur batteries and lithium-air batteries also have great development potential, which is expected to solve the self-discharge problem of lithium batteries in the future.
7. Recycling and recycling: For used lithium batteries, the self-discharge rate can be reduced by recycling and recycling. By recycling useful materials in old batteries, after treatment and then used in the production of new lithium batteries, it can not only reduce resource waste, but also reduce production costs and environmental pollution.

Fifth. Conclusion

In general, the self-discharge of lithium batteries is a complex problem that involves several factors. In order to reduce the self-discharge rate of lithium batteries, material selection, electrolyte modification, storage condition control, battery management system and other aspects can be started. At the same time, attention to the development of new battery structures and materials is also the key to solving this problem. With the continuous progress of technology and the expansion of application fields, we have reason to believe that the future can better control and solve the problem of lithium battery self-discharge, so as to better meet people's needs for energy and the pursuit of environmental protection.