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Temperature shock

Verifies the battery pack or system survives rapid alternation between hot and cold extremes — stressing differential thermal expansion, seals, and connector seating.
Clause (method) 8.2.8
Clause (pass criteria) 5.2.8
Object pack / system
Status vs. 2020 revised
Observation period 2 h at test environment temperature

Pass criteria

After the temperature shock test, the battery pack or system shall show no leakage, no housing crack, no fire, and no explosion. The insulation resistance after testing shall not be less than 100 Ω/V (DC), or 500 Ω/V if an AC circuit is present.

Source: GB 38031-2025, clause 5.2.8 (PDF p. 12).

Pre-conditions

  • Pre-treatment: Standard, per clause 7.2.
  • SOC: Highest working SOC per clause 6.1.10.
  • Insulation baseline: Measure before the test per Appendix B (clause 6.1.5).

Test parameters

Parameter Value Source
Low extreme −40 °C 8.2.8.2
High extreme 60 °C (or stricter if required by manufacturer) 8.2.8.2
Transition time between extremes ≤ 30 min 8.2.8.2
Hold time at each extreme 8 h 8.2.8.2
Number of cycles 5 8.2.8.2
Cycle profile Per Figure 11 8.2.8.2
Post-test observation 2 h at test environment temperature 8.2.8.3

Procedure

  1. Confirm pre-treatment per 7.2 and measure baseline insulation per Appendix B. (6.1.5)
  2. Adjust SOC to highest working value. (6.1.10)
  3. Place the test object in the temperature-shock chamber configured per Figure 11.
  4. Cycle the chamber between −40 °C and 60 °C (or the manufacturer's stricter extremes), with each transition completed in ≤ 30 minutes and an 8 h hold at each extreme. (8.2.8.2)
  5. Repeat for 5 cycles. (8.2.8.2)
  6. After the 5th cycle completes, observe the test object at the test environment temperature for 2 hours. (8.2.8.3)
  7. Re-measure insulation resistance per Appendix B. Inspect for leakage and housing cracks. Confirm no fire/explosion occurred.

After-test observation

Observe the test object for 2 hours at the test environment temperature (22 °C ± 5 °C) after the 5th cycle. (8.2.8.3)

What changed from GB 38031-2020

  • Listed in the preface change list as both requirements (5.2.8) and method (8.2.8) revised.

Migration impact: Already-type-approved vehicle models must comply from 2027-08-01. New type approvals from 2026-07-01. See Re-certification timeline.

Engineering notes (non-normative)

The notes below are practical interpretation, not part of the standard.

Engineering note (non-normative): Two-zone shock chambers (basket transfer) are the typical fixture for the ≤ 30 min transition requirement. A single-zone chamber that ramps in air will struggle to hit the 30-minute transition for a large pack — the thermal mass of the DUT dominates. Confirm the chamber category (single-zone ramp vs. two-zone shock) up front; they are not interchangeable for this test.

Engineering note (non-normative): Condensation inside the housing during the cold-to-hot transition is the typical failure mode that shows up later as low insulation. This is why the post-test insulation measurement matters — even if the pack visibly survives, internal moisture from the cycle can drop insulation below the 100 Ω/V threshold.