Pre-treatment cycles¶
Before the formal test starts, the test object cycles until its discharge capacity has stabilised. This produces the "actual capacity" used to set test currents and to verify the cell/pack against its rated capacity. The cell rule (three consecutive discharges within 3 %) is stricter than the pack rule (two consecutive cycles within 3 %), reflecting cell-to-cell variability.
Cell pre-treatment (7.1.2)¶
Before the formal test begins, the battery cell should first undergo a pre-treatment cycle. The steps are as follows: a) Perform standard charging on the battery cell according to 7.1.1; b) Discharge with a current not less than I₃ as specified by the manufacturer until the discharge termination condition specified by the manufacturer is reached; c) Let it stand for 1 hour (or a standing time not exceeding 1 hour as provided by the manufacturer); d) Repeat steps a) ~ c) up to 5 times.
If the discharge capacity variation of the battery cell is less than 3% of the rated capacity for three consecutive discharges, the battery cell is considered to have completed pre-treatment, and the pre-treatment cycle may be terminated. The average value of the last 3 test results will be taken as the actual capacity.
Termination logic for cells:
| Condition | Action |
|---|---|
| 3 consecutive discharges within ± 3 % of rated capacity | Stop. Actual capacity = average of last 3 |
| Not met after 5 cycles | Stop anyway (the standard caps repeats at 5) |
Source: clause 7.1.2.
Pack/system pre-treatment (7.2.2)¶
Before the formal test begins, the battery pack or system should first undergo a pre-treatment cycle. The steps are as follows: a) Charge with a current not less than I₃ or according to the manufacturer's recommended charging method until the manufacturer-specified charging termination condition is reached; b) Let it stand for 30 minutes or the time specified by the manufacturer; c) Discharge with a current not less than I₃ as specified by the manufacturer until the discharge termination condition specified by the manufacturer is reached; d) Let it stand for 30 minutes or the time specified by the manufacturer; e) Repeat steps a) ~ d) up to 5 times.
If the discharge capacity variation of the battery pack or system is not greater than 3% of the rated capacity for two consecutive cycles, the battery pack or system is considered to have completed pre-treatment, and the pre-treatment cycle may be terminated. The average value of the last 2 test results will be taken as the actual capacity.
Termination logic for packs/systems:
| Condition | Action |
|---|---|
| 2 consecutive cycles within ± 3 % of rated capacity | Stop. Actual capacity = average of last 2 |
| Not met after 5 cycles | Stop anyway |
Stand times are 30 min for packs versus 1 h for cells.
Source: clause 7.2.2.
Supplementary charge if > 24 h before test (7.2.2.3)¶
Unless otherwise specified, if the time interval between the completion of the pre-treatment cycle and the highest working state-of-charge and the start of a new test item exceeds 24 hours, a supplementary charge should be performed: charge with a current not less than I₃ until the charging termination condition specified by the manufacturer is reached, or according to the manufacturer's recommended charging method, and let it stand for 30 minutes or the time specified by the manufacturer.
Source: clause 7.2.2.3.
Actual capacity gate (6.1.9)¶
The actual capacity of the battery cell should not be less than the rated capacity and should not exceed 110% of the rated capacity. The absolute difference between the actual capacity and the rated capacity for the battery pack or system should not exceed 5% of the rated capacity.
| Object | Acceptable actual-capacity window |
|---|---|
| Cell | 100 % – 110 % of rated |
| Pack / system | within ± 5 % of rated |
Engineering note (non-normative): the asymmetric cell window (no negative tolerance) is the binding constraint. A cell that ages a few percent off the line will fall out of the 100 % floor before it falls outside the pack window. Building in a small safety margin (typically 102–108 %) on freshly formed cells avoids re-pulling samples partway through a test campaign.
Source: clause 6.1.9.
Where this is invoked¶
Pre-treatment is the prerequisite for every cell test (8.1.x) and every pack/system test (8.2.x). It runs once per test object before the first formal test; the standard does not require it to be repeated between tests on the same sample, but the supplementary-charge rule does kick in if more than 24 h passes.
Source¶
Clauses 6.1.9, 7.1.2, 7.2.2 (PDF page 14).