Today, I will write about the lithium battery aging. Aging is to load and run the product under a certain temperature and/or load. And then check whether the product’s performance indicators meet the technical requirements after a period of time.
Lithium-ion battery aging generally refers to the placement of the battery after the first charging at our battery factory. It can be aging at room temperature or high temperature. The purpose is to stabilize the properties and composition of the sei film formed after the initial charge. The room temperature aging temperature is 25 degrees, and the high temperature aging is different in different factories. Some are 38 degrees and 45 degrees, and the time is between 48-72 hours.
There are two types of lithium battery aging: opening aging and sealing aging:
Regarding the aging, if the relative humidity can be controlled below 2%, it is better to seal it.
Regarding high temperature aging, aging after sealing is better.
However, it is certain that the aging process has electrochemical kinetic changes. Which helps to the stability of sei and can promote the stability of the electrochemical system.
Regarding lithium-ion batteries, the principle and purpose of aging is to allow the electrolyte to fully infiltrate. and the other is to deactivate certain active components in the positive and negative active materials through a certain reaction, making the overall performance of the battery more stable. In order to speed up this process, many companies adopt high-temperature aging, but high-temperature aging should pay attention to controlling the time and temperature. Because high-temperature aging will cause more degradation of active substances than room-temperature aging. It is well controlled and the active ingredients are fully reacted. Stable performance, poor control, over-reaction, then electrical performance degradation, and even liquid leakage are very likely happened.
The performance of the battery after high temperature aging is more stable. Most lithium-ion battery manufacturers adopt high temperature aging operation mode. The temperature is 45~50 degrees Celsius for 1~3 days, and then put it aside at room temperature. Potential undesirable phenomena of the battery will be exposed after high temperature aging. For example, voltage changes, thickness changes, and internal resistance changes directly influence the safety and electrochemical performance.
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