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No fire, no explosion

"No fire" and "no explosion" are the two most common pass criteria in GB 38031-2025. They appear in every cell test (5.1.1 to 5.1.7), in the universal pack/system criterion (5.2.x), and as the headline criterion for thermal propagation (5.2.7 b) 1)). The standard defines both terms in clause 3 and the definitions are short — both turn on a precise threshold that test labs need to reproduce.

Definition — explosion (3.11)

The sudden release of energy sufficient to generate a pressure wave or projectiles.

Note: The pressure wave or projectiles may cause structural or physical damage to the surrounding area.

There is no quantitative threshold. The criterion is observational: did the event produce a pressure wave or projectiles? If yes, it counts as an explosion and the test is a fail.

Source: GB 38031-2025 clause 3.11 (PDF page 9).

Definition — fire (3.12)

A sustained combustion (flame duration greater than 1 second) occurring in any part of the battery cell, module, battery pack, or system.

Note 1: The duration of the flame exceeding 1 second refers to the duration of a single flame, not the cumulative duration of multiple flames.

Note 2: The judgment is made visually without dismantling the test object. Sparks and arcing do not constitute combustion.

Three load-bearing details:

  1. The 1-second threshold applies to a single flame. Multiple sub-second flames in succession do not aggregate into a "fire". A flame must individually persist for more than 1 s to count.
  2. Visual judgment, no dismantling. Test labs determine fire and explosion from the outside. They do not open the test object to look for internal combustion.
  3. Sparks and arcing are not fire. Electrical arcing during, e.g., an external short test is not, by itself, a failure of the no-fire criterion.

Source: GB 38031-2025 clause 3.12 (PDF page 9).

Engineering note (non-normative): The "single flame > 1 s" rule means high-speed video (or a competent observer with a clock) is the primary instrumentation. For tests where the cell vents and the gas auto-ignites in a brief flash, that flash is not a failure provided no individual flame exceeds 1 s. Document flame events with timestamps; do not summarize as "small flame, no fire" without the duration evidence.

Where this criterion applies

"No fire, no explosion" is the only pass criterion for cell-level tests:

Clause Test Method clause
5.1.1 Over-discharge 8.1.2
5.1.2 Overcharge 8.1.3
5.1.3 External short circuit 8.1.4
5.1.4 Heating 8.1.5
5.1.5 Temperature cycling 8.1.6
5.1.6 Extrusion (compression) 8.1.7
5.1.7 Safety after fast-charge cycles 8.1.8

For pack/system tests, "no fire, no explosion" is bundled with insulation, leakage, and housing-crack requirements as the universal "STD" criterion (see pass-fail index). Two pack/system clauses use only the no-fire/no-explosion subset:

  • 5.2.4 (compression, pack/system) — "should show no fire or explosion. The insulation resistance after testing should not be less than 100 Ω/V…" — leakage and housing cracks are not required to be absent.
  • 5.2.7 a) (external fire, pack/system) — "should not explode" — fire is allowed during the test (it is a fire test); only explosion fails it.
  • 5.2.6 a) (immersion, Method 1) — "there should be no fire or explosion."

Source: GB 38031-2025 clauses 5.1, 5.2 (PDF pages 11–12).

Cross-references