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Temperature cycling (cell)

Verifies a fully charged cell survives five repeated −40 °C ↔ 85 °C cycles without catching fire or exploding.
Clause (method) 8.1.6
Clause (pass criteria) 5.1.5
Object cell
Status vs. 2020 unchanged
Observation period 1 h at test environment temperature

Pass criteria

A battery cell, after undergoing the temperature cycling test according to 8.1.6, should not catch fire or explode.

There is no insulation requirement and no leakage/housing-crack requirement at cell level. (PDF p. 11)

Source: GB 38031-2025, clause 5.1.5 (PDF p. 11).

Pre-conditions

  • Sample: A battery cell. (8.1.6.1)
  • Active protection: Any additional active protection circuits or devices on the cell are removed. (8.1.1)
  • Starting state: Cell standard-charged per clause 7.1.1. (8.1.6.2)

Test parameters

One cycle per Table 1 (clause 8.1.6.3, PDF p. 16). The cycle is repeated 5 times.

Step Target T (°C) Time increment (min) Cumulative time (min) Ramp rate (°C/min)
Start 25 0 0 0
Ramp down −40 60 60 13/12
Hold cold −40 90 150 0
Ramp up 25 60 210 13/12
Ramp up 85 90 300 2/3
Hold hot 85 110 410 0
Ramp down 25 70 480 6/7
Parameter Value Source
Number of cycles 5 8.1.6.3
Duration per cycle 480 min (8 h) Table 1
Total cycling time 40 h Table 1 × 5
Observation period 1 h at test environment temperature 8.1.6.4

Procedure

  1. Confirm the test object is a single battery cell with active protection devices removed. (8.1.1, 8.1.6.1)
  2. Standard-charge the cell using the method described in clause 7.1.1. (8.1.6.2)
  3. Place the cell in the temperature chamber starting at 25 °C. (8.1.6.3)
  4. Drive the chamber through one cycle per Table 1 and Figure 1: ramp to −40 °C in 60 min, hold 90 min, ramp to 25 °C in 60 min, ramp to 85 °C in 90 min, hold 110 min, ramp back to 25 °C in 70 min. (8.1.6.3)
  5. Repeat step 4 for a total of 5 cycles. (8.1.6.3)
  6. After the fifth cycle completes, observe the cell for 1 h at the test environment temperature (22 °C ± 5 °C, per 6.1.1). (8.1.6.4)
  7. Record any fire or explosion event during cycling or observation.

After-test observation

Observe the test object for 1 h at the test environment temperature. (8.1.6.4)

Engineering notes (non-normative)

Engineering note (non-normative): Total elapsed time on chamber is roughly 41 h (5 × 8 h cycles + 1 h observation). Schedule the chamber accordingly — this is the longest cell-level test in Section 8.1 by an order of magnitude.

Engineering note (non-normative): The 13/12 °C/min ramp (≈ 1.083 °C/min) is the air-temperature rate the chamber must hit, not the cell internal rate. Verify chamber capability under load — a fully populated rack of large cells often cannot meet 13/12 °C/min ramp without auxiliary cooling.