Analysis of Li-ion battery capacity

Battery capacity is one of the important performance indicators of lithium-ion battery performance. It represents the amount of power stored in lithium-ion batteries under certain conditions, usually in Ah (Ampere-hour) or mAh (Milliamp-hour) as the unit (1Ahu003d1000mAh). The important method to obtain the capacity parameters of the ion battery is to integrate the current with time when the battery is discharged from 100% SOC to 0% SOC (that is, within the detection voltage range), that is, where Q is the battery capacity (Ah), I is the current (A) and t is the detection time (h). 1 milliampere hour is equivalent to 3.6 coulombs. Under normal circumstances, the capacity data can be directly read in the detection system software. Regarding the battery materials tested, capacity analysis generally determines three data: first charge capacity, first discharge capacity (cathode material) and reversible capacity. a. The first charge capacity is the charge capacity at the end of the first charge of the lithium-ion battery; b. The first discharge capacity is the discharge capacity at the end of the first discharge of the lithium-ion battery; c. The reversible capacity is the capacity value after the battery is cycled stable (the measured value at room temperature is also called the rated capacity). Generally, the discharge capacity of the 3rd to 5th week is selected, and the discharge capacity after 10 weeks may be selected. In practical applications, the analysis of the gram capacity, surface capacity and volume capacity of the test material or pole piece has more reference value. For example, gram capacity is the discharge capacity per unit mass of active material, Cu003dQ/m; area capacity is the discharge capacity per detection pole piece area, Cu003dQ/S; volume capacity is the discharge capacity per unit pole piece volume, Cu003dQ /V. In the formula, C is the discharge specific capacity mAh/g (milliampere-hour per gram), mAh/cm2 (milliampere-hour per square centimeter) or mAh/cm3 (milliampere-hour per cubic centimeter), and Q is the discharge capacity mAh (milliampere Ampere hours), m is the mass of the active material g (g), S is the detection pole piece area cm2 (square centimeter), and V is the detection pole piece volume cm3 (cubic centimeter). The gram capacity parameter is more intuitive to compare the performance of the test material, while the area capacity and volume capacity are more valuable for the actual application of the test material, when the positive and negative capacities are matched. It is recommended to provide 3 kinds of specific capacity information at the same time when publishing articles. 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 post: What is the difference between lithium ion battery and lithium ion polymer battery