Pass / fail criteria¶
This section unpacks the pass/fail vocabulary used throughout GB 38031-2025. The standard re-uses the same handful of criteria — "no fire", "no explosion", "no leakage", "no housing crack", insulation thresholds, the 5-minute thermal-event warning — across most of the 24 tests, and defines each term once in clause 3 (Terms and Definitions). Rather than repeat the definitions on every test page, we define them here and link out.
Pages in this section¶
| Page | What it covers |
|---|---|
| No fire, no explosion | Definitions 3.11 (explosion) and 3.12 (fire). The "single flame > 1 s" rule. How the judgment is made (visually, no dismantling). Why sparks and arcing don't count. |
| Leakage and housing crack | Definitions 3.13 (housing crack) and 3.14 (leakage). The visual-judgment rule. Which tests do not require "no leakage / no housing crack" (cell tests, external fire, pack compression). |
| Insulation resistance | The ≥100 Ω/V (DC) and ≥500 Ω/V (AC) thresholds. Where each clause requires them. Appendix B procedure (voltage-divider Method 1; insulation-meter Method 2). The "within 30 minutes" rule for damp heat. |
| The 5-minute warning | The flagship rule of the 2025 edition: thermal-event alarm signal must be issued no later than 5 minutes after thermal runaway is triggered. Smoke must not endanger the passenger compartment in the 10-minute window centered on the warning (vehicle-level: must not enter the cabin). Quotes 5.2.7 b) verbatim. |
| Observation periods | Quiet observation period after each test, by category. 1 h for cell + electrical-protection tests; 2 h for mechanical/environmental pack tests; 2 h or until external T < 45 °C for external fire; until all monitoring points ≤ 60 °C, min 2 h, for thermal propagation. |
Universal pass criterion (the "STD" shorthand)¶
The cheatsheet uses STD as shorthand on most pack/system test rows. Expanded, it means:
After test: no leakage, no housing cracks, no fire, no explosion. Insulation resistance ≥ 100 Ω/V (DC); ≥ 500 Ω/V if an AC circuit is present.
This pattern is repeated almost verbatim in clauses 5.2.1, 5.2.2, 5.2.3, 5.2.5, 5.2.8, 5.2.9, 5.2.10, 5.2.11, 5.2.12, 5.2.13, 5.2.14, 5.2.15, and 5.2.16. The exceptions are spelled out on the individual pages above and on the cheatsheet.
Source: GB 38031-2025 clause 5.2 (PDF pages 12).