Electrochemical test requirements for 7 large 18650 lithium batteries

1. Condition of charge retention capacity at room temperature: After standard charging of the battery, leave it in an open circuit for 28 days, and then discharge to the termination voltage at 0.2C5A. Requirements to meet the standard: discharge time ≥255min2, normal temperature discharge performance conditions: under the conditions of 1 standard atmosphere, ambient temperature 20℃±5℃, and relative humidity 45%~75%, after standard charging of the battery (if not specified below, All placed under this condition, all according to this charging method), put it aside for 30min, respectively discharge at 1C; A, 10C5A, 15C; A to the termination voltage, and cycle three times. When the standard is reached once, the standard requirements are met (the same below ). Requirements: A) 1C5A≥1h; B) 10C5A≥5.4min; C) 15CsA≥3.2min3, overcharge and overdischarge performance conditions: After the battery is standard charged, it is charged to 4.8V with a current of 3CsA, and then transferred to a constant voltage charge to It ends when the cut-off current is 0.01CsA. After the battery is standard charged, it is discharged with 1CsA to the termination voltage, and then the positive and negative poles of the battery are connected with a 10Q resistor and left for 14 days. Requirements: no fire, no explosion 4. Cycle life conditions: 1CsA/13C5A discharge to the termination voltage, put it aside for 30min, and cycle 300 times in this mode; requirements: discharge time ≥3.23min5 after 300 cycles, discharge at different temperatures Performance conditions: After standard charging, the battery should be stored at a constant temperature of 60±2℃ for 2h, discharged to the termination voltage at 0.2CsA, and then charged at room temperature in the order of 0±2℃/-20±2℃. Put it aside under the corresponding constant temperature condition for 16h, discharge at 0.2C; A to the termination voltage. Requirements: A) ≥285min at 60℃; B); ≥240min at 0℃; C) ≥180min at -20℃. The battery does not explode or catch fire. 6. Normal temperature short-circuit performance conditions: After the battery is standard charged, the positive and negative electrodes are directly short-circuited in an explosion-proof glass cover (total resistance of the circuit is not more than 50mQ), and the test ends when the battery temperature drops to about 10°C lower than the peak value. Observe the temperature and appearance changes of the battery. Requirements: no fire, no explosion. 7. Constant humidity and heat performance conditions: After standard charging, the battery is placed in a constant temperature and humidity box with a temperature of 40 ℃ ± 2 ℃ and a relative humidity of 90%. After leaving it for 48 hours, take out the battery for 20 ± Put it aside for 2h at 5℃. Observe the changes in the appearance of the battery. Then discharge to the final voltage with 0.2C3A. Requirements: Discharge time ≥180min. The battery does not catch fire or explode. Statement: Some pictures and content of the articles published on this site are from the Internet. If there is any infringement, please contact to delete. Previous: Battery PACK factory analyzes the opposite of the development of lithium batteries