Skip to content

Compression (cell)

Verifies a fully charged cell crushed slowly between a flat surface and a 75 mm semi-cylindrical plate does not catch fire or explode.
Clause (method) 8.1.7
Clause (pass criteria) 5.1.6
Object cell
Status vs. 2020 revised (method only)
Observation period 1 h at test environment temperature

Pass criteria

A battery cell, after undergoing the extrusion test according to 8.1.7, should not catch fire or explode.

There is no insulation requirement and no leakage/housing-crack requirement at cell level. (PDF p. 11)

Source: GB 38031-2025, clause 5.1.6 (PDF p. 11).

Pre-conditions

  • Sample: A battery cell. (8.1.7.1)
  • Active protection: Any additional active protection circuits or devices on the cell are removed. (8.1.1)
  • Starting state: Cell standard-charged per clause 7.1.1. (8.1.7.2)

Figure 6: Compression plate type 1 Figure 6 from GB 38031-2025 (PDF p. 21). Semi-cylindrical plate, radius 75 mm (半径75 mm), length L greater than the cell's compressed dimension.

Test parameters

Parameter Value Source
Compression direction Perpendicular to the cell's electrode plate, or the direction most likely to experience compression in the vehicle layout 8.1.7.3 a)
Plate form Semi-cylindrical 8.1.7.3 b)
Plate radius 75 mm 8.1.7.3 b)
Plate length L > cell dimension in the compressed direction (per Figure 6) 8.1.7.3 b)
Compression speed ≤ 2 mm/s 8.1.7.3 c)
Stop condition (any one of, whichever first) Voltage = 0, OR 15 % deformation, OR 100 kN, OR 1000 × test object mass 8.1.7.3 d)
Hold at stop position 10 min 8.1.7.3 e)
Observation period 1 h at test environment temperature 8.1.7.4

Procedure

  1. Confirm the test object is a single battery cell with active protection devices removed. (8.1.1, 8.1.7.1)
  2. Standard-charge the cell using the method described in clause 7.1.1. (8.1.7.2)
  3. Position the cell in the fixture so the compression load applies perpendicular to the electrode plate, or in the in-vehicle direction most likely to be compressed. (8.1.7.3 a)
  4. Configure the compression plate: semi-cylindrical, r = 75 mm, with length greater than the cell's compressed dimension. (8.1.7.3 b)
  5. Begin compression at ≤ 2 mm/s. (8.1.7.3 c)
  6. Stop compression at the first of the following: cell voltage reaches 0 V, deformation reaches 15 % of the original cell dimension in the compression direction, compressive force reaches 100 kN, or compressive force reaches 1000 × the cell's mass. (8.1.7.3 d)
  7. Hold the plate at the stop position for 10 min. (8.1.7.3 e)
  8. Release the load and observe the cell for 1 h at the test environment temperature (22 °C ± 5 °C, per 6.1.1). (8.1.7.4)
  9. Record any fire or explosion event during compression, hold, or observation.

After-test observation

Observe the test object for 1 h at the test environment temperature. (8.1.7.4)

What changed from GB 38031-2020

  • The test method was revised vs. the 2020 edition (8.1.7). The pass criterion (5.1.6) was not listed in the preface change list, so the requirement itself is unchanged.
  • (Source: GB 38031-2025 preface, PDF p. 6.)

Migration impact: Cells previously certified under the 2020 method should be re-tested under the 2025 method ahead of the 2026-07-01 effective date for new type approvals.

Engineering notes (non-normative)

Engineering note (non-normative): The four stop conditions are OR'd, so the test ends at whichever fires first — but for a small cell the 1000 × mass force ceiling can stop compression well before any of the others. For a 50 g pouch cell that's only ~490 N, far below the 100 kN limit. Pre-compute which stop condition will dominate for your sample so you instrument the right channel.

Engineering note (non-normative): Voltage cannot be measured during compression once the tabs separate or short. Use a four-wire connection clamped well outside the compression footprint, and treat sudden V = 0 as either the genuine stop condition or instrumentation loss — record displacement and force continuously so you can disambiguate post-test.

Engineering note (non-normative): "Length L greater than the cell width" (Figure 6) is the minimum; in practice a 10–20 mm overhang on each side avoids edge-loading artefacts that cause the cell to roll out of the plate.