Overview
GB/T 31485 is a Chinese national standard specifying safety requirements and test methods for lithium-ion traction battery cells and modules used in electric vehicles. Published by the Standardization Administration of China (SAC), it addresses safety behaviour at the cell and module level — complementing GB/T 31467-3, which covers safety at the battery pack and system level.
The standard is one of the foundational documents in China’s EV battery regulatory framework and is closely referenced in type approval processes for electric vehicles sold in China. It evolved from, and superseded, earlier automotive industry standards including QC/T 743, incorporating more comprehensive safety test regimes and updated pass/fail criteria.
Scope
GB/T 31485 applies to lithium-ion battery cells and modules used as traction batteries in road-going electric vehicles, including BEVs, PHEVs, and HEVs. The standard defines the safety tests that individual cells and assembled modules must pass to demonstrate that they do not present unacceptable fire, explosion, or toxic hazard risks under both normal operating and abuse conditions.
Key Requirements
The standard defines safety requirements for cells and modules under a range of stress conditions. Key requirements include that cells and modules must not catch fire or explode during or after any of the defined abuse tests. Electrolyte leakage is permitted in some test scenarios but must not lead to fire or explosion. The pass/fail criteria are binary for fire and explosion: any occurrence constitutes a failure regardless of severity.
Testing Requirements
GB/T 31485 specifies a comprehensive suite of safety tests applied at both cell and module level. Tests include overcharge (cells charged significantly beyond their rated upper voltage limit), over-discharge (cells discharged below minimum voltage), external short circuit (terminals connected through a low-resistance external path), heating (cells exposed to elevated temperatures in an oven), crush (cells compressed between flat plates), acupuncture or nail penetration (a metal nail driven through the cell to simulate internal short circuit), and immersion in water (verifying no hazardous reaction when submerged).
Test conditions specify the state of charge at the start of each test, the rate at which abuse is applied, the duration of exposure, and the observation period after the test concludes. Module-level tests extend these cell tests to the assembled module configuration, verifying that the module structure, interconnects, and local thermal environment do not amplify individual cell failures into module-wide hazardous events.
Relevance to Battery Design
For battery cell and module designers targeting the Chinese EV market, GB/T 31485 compliance is a mandatory step in the type approval process. The standard’s abuse tests, particularly nail penetration and overcharge, are among the most demanding safety assessments applied to EV cells globally and directly influence decisions about cell chemistry, electrode design, separator technology, electrolyte additives, and safety feature integration such as current interrupt devices and pressure vents. Understanding the standard’s requirements allows engineers to design internal safety margins that provide compliance headroom while optimising energy density and cost.