Electrochemical performance requirements for 18650 lithium ion battery testing
Before doing various tests, the 18650 lithium ion battery must be charged at 0.2CsA under the conditions of 86KPa~106KPa atmospheric pressure, ambient temperature of 20℃±5℃, and relative humidity of 45%~75%. When the voltage reaches the charging cut-off voltage, change to constant voltage charging, and stop charging until the charging current is less than or equal to 0.01C5A.
1. Discharge performance at room temperature
Conditions: at 1 standard atmosphere, ambient temperature 20℃±5℃, relative humidity 45%~75% Under the conditions, after the battery is standard charged (if there is no special instructions below, all are placed under this condition, all according to this charging method), put it aside for 30 minutes, respectively at 1C; A, 10C5A, 15C; A discharge to the termination voltage, and cycle three times , When the standard is met once, the standard requirement is met (the same below).
Requirements meet: A) 1C5A≥1h; B) 10C5A≥5.4min; C) 15CsA≥3.2min
2, normal temperature charge retention ability
Conditions: After the battery is standard charged, leave it in an open circuit for 28 days, and then discharge to the termination voltage at 0.2C5A.
Required to meet the standard: discharge time ≥255min
3, cycle life
Conditions: 1CsA/13C5A discharge to the termination voltage, set aside for 30min, and cycle in this mode 300 times;
Required: discharge time ≥3.23min after 300 cycles
4. Overcharge and overdischarge performance
Conditions: After standard charging of the battery , Charge to 4.8V with a current of 3CsA, and then switch to constant voltage charging to terminate when the cut-off current is 0.01CsA. After standard charging of the battery, discharge it to the final voltage with 1CsA, then connect the positive and negative poles of the battery with a 10Q resistor and leave it for 14 days.
Requirements: no fire, no explosion
5, normal temperature short-circuit performance
Conditions: After the battery is standard charged, it is directly short-circuited in the explosion-proof glass cover The positive and negative poles (the total resistance of the circuit is not more than 50mQ), 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 to meet: no fire, no explosion
6. Discharge performance at different temperatures
Conditions: After the battery is standard charged, at 60±2℃ Shelve at constant temperature for 2h, discharge at 0.2CsA to the end voltage, and then standard charge at room temperature, in turn follow the order of 0±2℃/-20±2℃ and put it aside for 16h under corresponding constant temperature conditions, discharge at 0.2C; A To the termination voltage.
Requirements: A) ≥285min at 60℃; B); ≥240min at 0℃; C)≥180min at -20℃
The battery will not explode or catch fire.
7. Constant heat and humidity performance
Conditions: After standard charging, the battery should be placed in a constant temperature and humidity box with a temperature of 40℃±2℃ and a relative humidity of 90% for 48 hours. After that, take out the battery and put it aside at 20±5℃ for 2h. Observe the changes in the appearance of the battery. Then discharge to the final voltage with 0.2C3A.
Required to meet: discharge time ≥180min, battery does not catch fire or explode