Cell test methods

1

Discharge rate performance

A）Discharge Performance (0.2C) ≥100％Rated Capacity
B）Discharge Performance (0.5C) ≥95％Rated Capacity
C）Discharge Performance (1C) ≥90％Rated Capacity
D）Discharge Performance (2C) ≥80％Rated Capacity
E）Discharge Performance (3C) ≥80％Rated Capacity

The cell is charged according to standard charge method, and then, it is discharged to 2.75V using 0.2C current; after, the cell is charged according to standard charge method, and then, it is discharged to 2.75V using 0.5C current; The cell is charged according to standard charge method, and then, it is discharged to 2.75V using 1.0C current; At the end, the cell is charged according to standard charge method, and then, it is discharged to 2.75V using 2.0C current;
The discharge capacities under different current shall be recorded.

2

Cycle life

≥600cycle

Under room temprature, the cell is charged to 4.2V using 0.5C current and then store it for 10 min. Then it is discharged to 2.75V using 0.5C current. Recycle it continuously till the residual capacity is less than 70% of the rated capacity.

3

High-Low temperature discharge performance

Discharge capacity/ initial capactiy×100％
A)60℃≥95% rated capacity
B)0℃≥80％rated capacity
C)-10℃≥70% rated capacity
D)-20℃≥55% rated capacity
No obvious outside damage, No leakage, No smoke, No explosion

Test the batteries’ initial state and capacity , after standard charging, store it at 60±2℃ for 3 hours, discharge at 0.2C5mA to 2.5V, then make standard charging under room temperature. Then Store it at corresponding constant temperature for 3h under 0±2 ℃/-10±2 ℃/-20±2 ℃ in order. Then discharge the cell at 0.2C5mA to 2.5V and meanwhile make a capacity record. At last store it at room temperature for 2 hours and observe the cell appearance.

4

Storage performance

Residual Capacity≥90％Rated Capacity
Recovery Capacity≥98% Rated Capacity
Internal resistance increase rate≤30％

After standard fully charge, make standard discharge. This capacity is recorded as initial discharge current. Then the cell is fully charged according to standard charge method and stored at 25℃ for 28 days. After storage, the cell is discharged according to the requirement of standard discharge method. This discharge capacity is named as the Residual capacity. And then charge and discharge the cell by 0.5C. This discharge capacity is recorded as the Recovery capacity.