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Simulated collision

Verifies a battery pack or system survives the longitudinal and lateral acceleration pulse representative of a vehicle crash event without losing electrical safety.
Clause (method) 8.2.3
Clause (pass criteria) 5.2.3
Object pack / system
Status vs. 2020 revised (requirements only)
Observation period 2 h at test environment temperature

Pass criteria

After the simulated collision 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 5.2.3 (PDF p. 12).

Pre-conditions

  • Sample: A battery pack or system. (8.2.3.1)
  • Pre-treatment: Standard, per clause 7.2.
  • SOC: Highest working SOC per clause 6.1.10.
  • Mounting: Horizontally on a cart with brackets, per the test object's vehicle installation position and fixation method, following GB/T 2423.43. (8.2.3.2)
  • Insulation baseline: Measure before the test per Appendix B (clause 6.1.5).

Test parameters

The pulse envelope is determined by the vehicle curb-weight class of the host vehicle. The pulse must be applied along both the x-axis and the y-axis.

Common Value Source
Test axes x and y (vehicle driving direction = x; perpendicular horizontal = y) 8.2.3.2
Mounting Horizontal on cart with brackets, per GB/T 2423.43 8.2.3.2
Multi-orientation rule If pack supports multiple installation orientations (x/y/z), test in the orientation with the highest acceleration 8.2.3.2
Pulse envelope Per Table 6 / Figure 5 (control points A–H) 8.2.3.2
Observation after test 2 h at test environment temperature 8.2.3.3

Pulse tolerance envelope (Table 6)

The acceleration pulse on the cart must lie within the envelope defined by the eight control points (A–H) below, for both the x-direction and y-direction acceleration, by curb-weight class.

Point Pulse width (ms) ≤3.5 t x-acc (g) ≤3.5 t y-acc (g) >3.5 to <7.5 t x-acc (g) >3.5 to <7.5 t y-acc (g) ≥7.5 t x-acc (g) ≥7.5 t y-acc (g)
A 20 0 0 0 0 0 0
B 50 20 8 10 5 6.65 —
C 65 20 8 10 5 6.65 —
D 100 0 0 0 0 0 0
E 0 10 4.5 5 2.5 4 2.5
F 50 28 15 17 10 12 10
G 80 28 15 17 10 12 10
H 120 0 0 0 0 0 0

⚠ verify: The PDF text extraction shows the ≥7.5 t row at points B and C as "6.65" without an explicit y-acc value; treat the y-acc cell at B/C in that band as not separately listed and confirm against the original Table 6 figure on PDF p. 20.

Peak summary (point F/G, the high-acceleration plateau):

Curb-weight class Peak x-acceleration (g) Peak y-acceleration (g)
≤ 3.5 t 28 15
> 3.5 to < 7.5 t 17 10
≥ 7.5 t 12 10

Procedure

  1. Mount the test object horizontally on a sled cart with brackets, per its vehicle installation position and fixation method, following GB/T 2423.43. (8.2.3.2)
  2. Determine the host vehicle's curb-weight class (≤3.5 t / >3.5 to <7.5 t / ≥7.5 t) and select the corresponding column pair from Table 6.
  3. Apply the specified acceleration pulse to the cart along the x-axis, ensuring the pulse lies within the Table 6 / Figure 5 envelope. (8.2.3.2)
  4. Repeat with the pulse along the y-axis. (8.2.3.2)
  5. For multi-orientation installations, perform along the orientation with the highest acceleration. (8.2.3.2)
  6. After both axes complete, observe the test object for 2 h at test environment temperature. (8.2.3.3)
  7. 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 pulse. (8.2.3.3)

What changed from GB 38031-2020

The 2025 revision changed the requirements only (5.2.3). The test method (8.2.3) — sled-cart pulse on x and y, envelope per Table 6 by curb-weight class — is unchanged from 2020.

  • 5.2.3 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. Compliance with the revised 5.2.3 wording (insulation re-measurement after collision pulse) 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 pulse envelope sets a floor and ceiling — labs are free to use any actual pulse shape (typically half-sine or trapezoidal) as long as it stays inside the A–H boundary. The "F/G plateau" between 50 and 80 ms is what dominates the energy delivered; tuning the cart to land cleanly inside that plateau matters more than chasing the exact shape.

Engineering note (non-normative): Curb-weight class is the host vehicle's weight, not the pack mass. A 200 kg pack used in a 2.8 t M1 sedan and the same pack used in a 4 t N2 light truck see different envelopes. For modular pack programs that span multiple vehicle classes, expect to run the test against the most-stringent (≤3.5 t) envelope to certify the worst-case host.

Engineering note (non-normative): The "two test objects" allowance from compression (8.2.4) does not appear here — both x and y pulses must be applied, but the standard does not explicitly forbid using two samples. In practice, labs use a single sample fixtured to receive both pulses sequentially, with the more damaging axis run last so post-test inspection captures cumulative damage.