What are the causes of lithium battery capacity attenuation?

　　Author ：Iflowpower – Portable Power Station Supplier

What is the reason for lithium-ion battery capacity attenuation? 1. Lithium-ion battery abuse The lithium-ion battery is less than 120% of SOC, there is no significant capacity loss; when SOC is more than 120%, lithium deposition is started, and the impedance becomes larger and causes activity due to generate thicker SEI membranes. Loss of lithium, if you continue to overcharge, it will cause lithium-ion battery thermal out of control.

Under too high SOC, the decomposition rate of the electrolyte will become fast, and a thick deposition layer is formed in the graphite negative electrode, and the lithium contained in the deposition layer is precipitated. In addition, large rate charge and discharge can also cause lithium ion battery capacity loss, because the positive negative electrode will shrink and expand in the charge and discharge process, the larger the charge and discharge current, the more intense contraction, the greater the stress, thus The particles of the negative electrode are more likely to rupture in the rapid variation of the volume or peel off from the current fluid, resulting in a cycle attenuation. 2.

Temperature factors have to mention that the use of lithium-ion batteries and the damage of their capacity. The temperature is definitely one of the key factors affecting the life of the lithium-ion battery. The excessive temperature or excessive temperature can cause a decrease in the active lithium ion content, the electrode material structure is destroyed, and the metal ion is dissolved, resulting in severe capacity attenuation.

Conventional lithium-ion battery operating temperature: -20 ¡ã C ~ 60 ¡ã C, but generally lower than 0 ¡ã C, the lithium ion battery performance will decrease, and the discharge capacity will reduce it, so the lithium ion battery performance is completely working temperature, common is 0 ~ 40 ¡ã C. Some special environmental requirements of the lithium-ion battery temperature is different, and some can even run normally in the environments of hundreds of degrees. Under low temperature conditions, the viscosity of the electrolyte increases, the ion conductivity is slow, and the electronic migration speed of the external circuit does not match, the battery is severely polarized, and the charge and discharge capacity has a sharp decrease.

In particular, in the case of low temperature charging, Li + from the positive electrode migration will occur in the carbon layer layer embedded to the negative electrode, a lithium metal crystallization is formed in the negative terminal, resulting in a decrease in the battery capacity, and the charging will cause a lithium branch at a long time. Crystal puncture diaphra.