Symbols and abbreviations¶
From GB 38031-2025, Section 4.
Symbols (4.1)¶
| Symbol | Meaning | Numerical relationship |
|---|---|---|
| I₁ | 1-hour rate discharge current (A) | I₁ value = the rated capacity value (numerically) |
| I₃ | 3-hour rate discharge current (A) | I₃ = I₁ / 3 (i.e., one-third of the rated capacity value) |
Engineering note (non-normative): Many test procedures specify a discharge current of "≥ I₃". For a pack with a 100 Ah rated capacity, this means a current of at least ~33 A. I₁ corresponds to a 1C discharge; I₃ corresponds to a C/3 discharge in C-rate notation. The standard avoids C-rate notation in favor of these symbols.
Abbreviations (4.2)¶
| Abbrev. | Term |
|---|---|
| BCU | Battery Control Unit |
| FS | Full Scale (used for instrument accuracy specifications, e.g., ±0.5% FS) |
| PSD | Power Spectral Density (used in vibration test parameter tables) |
| RMS | Root Mean Square (used for vibration test acceleration values) |
| SOC | State-of-Charge |
Other terms used in the standard but not formally listed in §4¶
These appear repeatedly in test methods. Not in the formal abbreviations list, but worth knowing:
| Term | Meaning | First seen |
|---|---|---|
| BMS | Battery Management System | Clause 9.1 j) |
| IPX7 | IP code for water ingress protection (immersion to 1 m for 30 min) | Clause 5.2.6 b), references GB/T 4208-2017 |
| CC / CV | Constant Current / Constant Voltage (charging modes) | Clause 7.1.1 |
| dT/dt | Temperature rise rate | Clause C.5.3.7 |
Source: GB 38031-2025, Section 4 (PDF p. 11).