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Environmental tests — pack / system

Five tests in GB 38031-2025 that stress the battery pack or system through environmental conditions: humidity, water immersion, thermal cycling, salt corrosion, and altitude.

# Clause Test Pass clause Key parameters Page
13 8.2.5 Damp heat cycling 5.2.5 GB/T 2423.4 Test Db; max 60 °C; 5 cycles; insulation measured within 30 min of test end damp-heat-cycling.md
14 8.2.6 Immersion 5.2.6 Method 1: 3.5 % NaCl, 2 h (no fire/no explosion). Method 2: IPX7 per GB/T 4208-2017 §14.2.7, 30 min, fresh water (full STD). Must have first passed 8.2.1 immersion.md
15 8.2.8 Temperature shock 5.2.8 −40 °C ↔ 60 °C; transition ≤ 30 min; 8 h hold each; 5 cycles temperature-shock.md
16 8.2.9 Salt fog 5.2.9 NaCl (50 ± 5) g/L; pH 6.5–7.2 @ 35 °C; 24 h cycles (8 h spray + 16 h dwell); 6 cycles total. Exempt if pack fully inside passenger/luggage/closed cargo compartment salt-fog.md
17 8.2.10 High altitude 5.2.10 61.2 kPa (~4 000 m); stand 5 h; discharge ≥ I₃ to termination high-altitude.md

Universal pass criterion

All five environmental tests apply the STD criterion (no leakage, no housing crack, no fire, no explosion + insulation ≥ 100 Ω/V DC, ≥ 500 Ω/V if AC), with two structural exceptions:

  • 8.2.5 specifies the post-test insulation measurement must be made within 30 minutes after testing.
  • 8.2.6 offers two methods with distinct pass criteria: Method 1 = no fire / no explosion only; Method 2 = full STD plus IPX7 conformance.

Observation period

All five tests use a 2-hour observation at the test environment temperature, except 8.2.9 (salt fog) which does not specify a separate observation period — the 6-cycle exposure constitutes the test.