GB 38031 - Battery Design

Electric Vehicles Traction Battery Safety Requirements (China National Standard)

GB 38031 is a mandatory Chinese national standard that specifies safety requirements and test methods for traction battery systems used in electric vehicles sold in China. It is published by the Standardization Administration of China (SAC) and is enforced by the Ministry of Industry and Information Technology (MIIT). Compliance is required for vehicle type approval and market access in China. GB 38031-2020 replaced GB/T 31485-2015 and GB/T 31467.3-2015 as the primary mandatory traction battery safety standard, coming into effect on 1 January 2021. The revised edition GB 38031-2025 was published in 2025 and is effective from 1 July 2026, dramatically raising requirements with a 2-hour no-fire/no-explosion mandate and a suite of new tests.

Published by: Standardization Administration of China (SAC) / Ministry of Industry and Information Technology (MIIT)

Current edition: GB 38031-2025 (effective 1 July 2026); GB 38031-2020 (effective 1 January 2021, remains in force until transition)

Replaces: GB/T 31485-2015 (safety requirements) and GB/T 31467.3-2015 (abuse test methods)

Status: Mandatory (GB prefix = guobiao mandatory standard) — compliance required for China market MIIT vehicle type approval

Test scope (2025 edition): 7 single-cell tests and 17 battery pack or system tests

Scope

GB 38031 applies to traction battery systems (packs) in electric vehicles intended for sale and use in China, including:

Battery Electric Vehicles (BEVs): passenger cars, SUVs, commercial vehicles
Plug-in Hybrid Electric Vehicles (PHEVs): parallel and series hybrid architectures
Hybrid Electric Vehicles (HEVs): full and mild hybrid systems

Exclusions: L-category vehicles (motorcycles, scooters) are covered by separate Chinese standards. The standard applies to the complete traction battery pack and system as installed in the vehicle.

GB 38031-2020 — Key Requirements (Effective 1 January 2021)

Mandatory Safety Tests

Vibration: sweep sinusoidal vibration in three axes — no leakage, fire, explosion, or rupture
Mechanical shock: shock applied per defined waveform — same pass criteria as vibration
Simulated collision (impact): frontal deformation of battery housing to simulate crash — no fire or explosion
Crush: compressive force applied to battery system — no fire or explosion; moderate deformation accepted
Immersion in water: battery system immersed at 1 m depth for 2 hours — no fire or explosion; insulation resistance maintained
Thermal stability (oven test): battery system heated to defined temperature — no fire or explosion
Short circuit protection: external short at elevated temperature — protection must interrupt current; no fire or explosion
Overcharge protection: battery charged above maximum permitted voltage — protection must activate; no fire or explosion
Over-discharge protection: BMS must terminate discharge below minimum voltage

Thermal Propagation Test — 2020 Edition

A single cell within the assembled pack is triggered into thermal runaway. The 2020 standard requires that for at least 5 minutes after the onset of thermal runaway in the trigger cell, there is no fire or explosion from the battery pack. This is intended to allow vehicle occupants sufficient time to evacuate.

GB 38031-2025 — Key Updates (Effective 1 July 2026)

The 2025 edition introduces five major updates that significantly raise the safety bar for EV traction batteries:

2-Hour Fireproof Mandate: batteries must survive 2 hours without fire or explosion after thermal runaway, with battery surface temperatures remaining ≤60°C. This is a step-change from the 5-minute requirement in the 2020 edition and forces fundamental pack architecture changes to manage thermal propagation.
5-Minute Alert System: immediate alarms must activate and there must be zero toxic fumes in the vehicle cabin post-thermal runaway within 5 minutes, giving occupants clear warning and time to exit safely.
New Physical Impact Tests: a bottom impact test using a 30 mm steel ball at 150 J energy simulates road debris strikes to the battery pack floor. Internal heating simulations are also added to replicate real-world internal failure scenarios. No fire or explosion is permitted.
Fast-Charge Durability: batteries must pass all safety checks after 300 ultra-fast charge cycles (20–80% SOC), verifying that repeated DC fast charging does not degrade safety performance.
Salt Spray and Delayed Combustion Checks: extended salt spray exposure tests combined with delayed combustion monitoring address hidden risks from corrosion of pack enclosures and slow-onset thermal events that may not manifest immediately after the primary test.

The impact of these changes is very significant and wide ranging for battery pack designers, cell suppliers, and OEMs selling into the China market.

China Market Type Approval

MIIT approval: all EV models must appear in the MIIT Vehicle Product Catalogue; GB 38031 compliance is tested at CATARC or CATARC-accredited laboratories
Transition to 2025 edition: new vehicle type approvals must reference GB 38031-2025 from 1 July 2026; existing approvals may continue under the 2020 edition until the transition deadline
Localisation: foreign OEM vehicles must comply with GB 38031 for China-market versions with China-spec battery packs

Related Standards

ISO 6469-1 — EV RESS safety specifications for persons (international equivalent person-protection approach)
ISO 12405-4 — ISO performance testing for Li-ion traction battery packs; international performance tests referenced alongside GB 38031
ECE R136 — UN Regulation for electric L-category vehicle safety; EU safety approach for smaller EVs
UN GTR 20 — Global Technical Regulation on the Safety of Electric Vehicles; GB 38031 aligns with GTR 20 core requirements
GB/T 36276-2023 — Safety requirements for Li-ion batteries for energy storage systems (stationary storage counterpart)

Disclaimer: This is not a definitive guide, just an indication and it is important that you always go back to the source for legislation.