Lithium battery pack aging and safety test analysis

Lithium battery pack aging test: The activation phase of lithium battery pack includes pre-charging, formation, aging, constant volume and other stages. The purpose of aging is to stabilize the properties and composition of the SEI film formed after the initial charge. The lithium battery aging test is to make the electrolyte infiltration better, which is conducive to the stability of the battery performance; after a period of aging, the consistency of the lithium battery pack is screened. After formation, the voltage of the battery cell is unstable, and its measured value will deviate from the actual value. The voltage and internal resistance of the battery cell after aging are more stable, which is convenient for screening batteries with high consistency. The performance of the battery after high temperature aging is more stable. Most lithium battery manufacturers adopt high temperature aging operation mode during processing. The temperature is 45~50 degrees Celsius for 1 to 3 days, and then the battery is left 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 all directly test the comprehensive indicators of the safety and electrochemical performance of this batch of batteries. Lithium battery safety test: In view of the safety risks that lithium batteries may encounter in actual use, we have designed safety tests such as extrusion, acupuncture, short circuit, overcharge and overdischarge, high and low temperature. Among the many safety tests, the squeeze, acupuncture and external short-circuit tests that simulate internal and external short-circuits of lithium batteries are the most conventional and the most difficult to pass. The reason is that the instantaneous current is too large in these two safety tests. Due to factors such as ohmic impedance, a large amount of heat appears inside the lithium battery for a period of time. Due to the limitation of the structure of the lithium battery, this heat cannot quickly diffuse to the battery. Externally, the temperature of the lithium battery is too high, which triggers the decomposition and combustion of the active material and the electrolyte, leading to thermal runaway. Disclaimer: The articles published on this website are all from the Internet. If there is any infringement, please contact to delete it. Disclaimer: Some pictures and content of articles published on this site are from the Internet. If there is any infringement, please contact to delete. Previous: Analysis of the causes of common battery processing problems