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Mechanical shock

Verifies a battery pack or system survives the half-sine acceleration pulse representative of vehicle-level shock events (curb strikes, suspension bottoming) without losing electrical safety.
Clause (method) 8.2.2
Clause (pass criteria) 5.2.2
Object pack / system
Status vs. 2020 revised (requirements only)
Observation period 2 h at test environment temperature

Pass criteria

After the mechanical shock test, the battery pack or system shall show no leakage, no housing crack, no fire, and no explosion. 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 5.2.2 (PDF p. 12).

Pre-conditions

  • Sample: A battery pack or system. (8.2.2.1)
  • 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
Shock waveform Half-sine Table 4 (8.2.2.2)
Test direction ±z Table 4 (8.2.2.2)
Peak acceleration 7 g Table 4 (8.2.2.2)
Pulse duration 6 ms Table 4 (8.2.2.2)
Number of shocks 6 in +z and 6 in −z (12 total) Table 4 (8.2.2.2)
Inter-shock interval ≥ 5× pulse duration (i.e., ≥ 30 ms) 8.2.2.4
Pulse tolerance envelope Per Table 5 / Figure 4 8.2.2.3
Observation after test 2 h at test environment temperature 8.2.2.5

Pulse tolerance envelope (Table 5)

The half-sine pulse must lie inside the tolerance envelope defined by the eight control points below.

Point Pulse width (ms) ±z acceleration (g)
A 1.00 0.00
B 2.94 5.95
C 3.06 5.95
D 5.00 0.00
E 0.00 2.68
F 2.00 8.05
G 4.00 8.05
H 7.00 0.00

Procedure

  1. Mount the test object on the shock table per its in-vehicle fixation method.
  2. Apply a half-sine shock pulse with peak 7 g and pulse width 6 ms in the +z direction. (8.2.2.2, Table 4)
  3. Wait for the response to decay — interval ≥ 5× pulse duration (≥ 30 ms). (8.2.2.4)
  4. Repeat for a total of 6 shocks in +z.
  5. Repeat the sequence for 6 shocks in −z, for 12 shocks total. (8.2.2.2)
  6. Verify each pulse lies within the Table 5 / Figure 4 tolerance envelope. (8.2.2.3)
  7. After all shocks, observe the test object for 2 h at test environment temperature. (8.2.2.5)
  8. Re-measure insulation resistance per Appendix B. Inspect for leakage, housing cracks, fire, or explosion.

After-test observation

Observe the test object for 2 hours at the test environment temperature (22 °C ± 5 °C) after the last shock. (8.2.2.5)

What changed from GB 38031-2020

The 2025 revision changed the requirements only (5.2.2). The test method (8.2.2) — half-sine, 7 g, 6 ms, ±z, 12 total shocks — is unchanged from 2020.

  • 5.2.2 was revised to align with the universal STD pack/system criterion: explicit insulation thresholds (100 Ω/V DC, 500 Ω/V AC) following the test, alongside no leakage/crack/fire/explosion.

Migration impact: Re-test of the method is generally not required — existing 8.2.2 test data should map directly. Compliance with the revised 5.2.2 wording (insulation re-measurement after shock) must be demonstrated for type approval. See Re-certification timeline.

Engineering notes (non-normative)

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

Engineering note (non-normative): The "interval ≥ 5× pulse duration" rule (≥ 30 ms here) exists so that the second shock starts from a quiet baseline, not a ringing structure. In practice, labs often use longer intervals (1–5 s) to allow the data acquisition to settle and to inspect the fixturing between shocks.

Engineering note (non-normative): The shock is z-axis only — vertical. There is no x or y shock requirement here; lateral and longitudinal shock loading is covered by the simulated collision test (8.2.3). When planning a campaign, do not double up: 8.2.2 hits the suspension-bottoming case, 8.2.3 hits the crash-pulse case.