With the continuous development of lithium battery skills, and the strong support of lithium batteries and new energy technologies in various countries around the world, large-scale lithium battery energy storage system equipment has now been increasingly developed and used. So what is the reason for the decline of lithium battery capacity? 18650 lithium ion battery supplier to share with you:
1. Unusual use of lithium batteries
Lithium batteries have no significant capacity loss when the charge share of the lithium battery is less than 120%; when the charge share of the lithium battery is more than 120%, the negative electrode exhibits lithium deposition at the beginning, and because of the thicker SEI film, the impedance becomes larger and Causes the loss of active lithium, if it continues to overcharge, it will cause thermal runaway of lithium battery. With an excessively high charge rate of the lithium battery, the differentiation rate of the electrolyte will become faster. A thick deposition layer is formed on the graphite negative electrode, and the lithium contained in the deposition layer is deposited.
世界杯预选赛竞猜In addition, large-rate charge and discharge will also cause the loss of lithium battery capacity. This is because the positive and negative electrodes will experience volume reduction and swell during the charge and discharge process. The larger the charge and discharge current, the more severe the shortening and swell, and the greater the stress. The particles of the negative electrode are more likely to crack or peel from the current collector during rapid volume changes, resulting in faster cycle attenuation.
2. Temperature factor
It must be mentioned that the operating environment and conditions of the 18650 cylindrical battery damage its capacity. Temperature is definitely one of the key factors affecting the life of lithium batteries. Too high or too low temperatures will cause the content of active lithium ions to decrease, the electrode data structure to be damaged, and metal ions to dissolve, which will cause serious capacity degradation.
Conventional lithium battery operating temperature: -20 ℃ ~ 60 ℃, but generally lower than 0 ℃, the function of lithium battery will decrease, and the discharge will decrease accordingly, so the complete working temperature of lithium battery function is usually 0 ~ 40 ℃ . Some special environments require different lithium battery temperatures, and some can even operate normally in environments with hundreds of degrees Celsius.
Under low temperature conditions, the viscosity of the electrolyte increases, the ion conduction speed becomes slower, which does not match the electronic relocation speed of the external circuit, the battery appears severely polarized, and the charge and discharge capacity declines sharply. Especially in the case of low-temperature charging, it will appear that Li + moved from the positive electrode is too late to be embedded in the carbon layer of the negative electrode, forming lithium metal crystals at the negative electrode terminal, resulting in a decrease in battery capacity. Charging at a low temperature for a long time will cause lithium branches. The crystal pierced the diaphragm and caused a short circuit.
18650 Cylindrical Battery
The influence on the capacity decay of 2200mAh Li-ion battery世界杯预选赛竞猜 is mainly the structural damage or deactivation of the positive and negative electrode data, the differentiation of the electrolyte, the misuse of lithium batteries, and so on. The charge and discharge process of a battery is a messy electrochemical process, and the factors that cause the battery capacity to decay are not single, and the deterioration in one aspect may cause other factors to affect the battery capacity, cycle function, energy density, etc.