Overview
GB/T 31484 is a Chinese national standard specifying cycle life requirements and test methods for lithium-ion traction battery packs and systems used in electric vehicles. Issued by the Standardization Administration of China (SAC), the standard establishes the minimum acceptable cycle life performance that battery packs must demonstrate before entering the Chinese EV market.
The standard sits alongside GB/T 31467-3 (pack and system safety) and GB/T 31485 (cell and module safety) as part of the core Chinese national standard framework for EV traction batteries. While the other standards focus on safety under abuse or extreme conditions, GB/T 31484 specifically addresses degradation performance over the operational lifetime of the pack.
Scope
GB/T 31484 applies to lithium-ion traction battery packs and systems used in battery electric vehicles (BEV) and hybrid electric vehicles (HEV/PHEV) sold in China. The standard defines the cycle life test procedure and the minimum number of charge/discharge cycles a battery pack must complete while retaining a specified capacity retention, before being considered compliant.
Key Requirements
The standard requires that traction battery packs demonstrate a minimum cycle life under defined charge and discharge conditions. Packs must retain a specified percentage of their initial capacity after completing the required number of cycles. The test is designed to simulate realistic vehicle operating conditions, with current rates and temperature ranges representative of typical EV use.
Capacity is measured at key intervals throughout the test to track degradation curves and confirm that the pack meets the retention threshold at the end of the defined cycle count. The standard also specifies requirements for how packs are conditioned before testing begins, ensuring consistent and reproducible results across different manufacturers and test laboratories.
Testing Requirements
The cycle life test procedure involves repeated charge/discharge cycling of the battery pack under controlled temperature conditions. Key test parameters include the charge and discharge current rates (C-rates), temperature range during cycling, depth of discharge for each cycle, frequency of capacity check measurements, and the total number of cycles to be completed. The test concludes with a final capacity measurement to confirm the retention level relative to the initial measured capacity.
Pass/fail criteria are based on capacity retention: the pack must still deliver at least the specified percentage of its original capacity after completing the full cycle count. Packs that fall below this threshold before completing the test are considered non-compliant.
Relevance to Battery Design
GB/T 31484 compliance is a key requirement for EV battery packs targeting the Chinese market. For battery engineers, the standard informs decisions about cell chemistry selection, electrode design, electrolyte formulation, and thermal management, all of which affect cycle life performance. Understanding the test conditions and pass/fail thresholds allows designers to set appropriate internal margins and validate that pack-level cycle life targets are met before entering regulatory testing. The standard also provides a reference benchmark for comparing the longevity of different battery chemistries and pack architectures under comparable conditions.