step 1

Capacity and DC impedance calibration at room temperature (25˚C)

step 2

At constant temperature (25 0.5C), the discharge was 2.8V constant at constant flow rate

step 3

Hold the battery for 5 hours at low temperature (X˚C)

step 4

At low temperature (X˚C), the charge is first charged at 0.5C constant current to 4.2V, then the constant voltage is charged until the current is less than or equal to 0.1C.

step 5

0.5C constant current discharge at low temperature (X˚C)

step 6

Capacity and DC impedance calibration at room temperature (25˚C)

step 7

Repeat 2 steps 2 - step 6

step 8

Replace the battery, change X, repeat step 1 - step6