China has introduced a new national standard designed to improve transparency around electric vehicle battery health, establishing standardised methods for measuring battery degradation and limiting the difference between displayed and actual battery capacity.
The voluntary standard, GB/T 46991.1-2025, was jointly developed by the Ministry of Industry and Information Technology (MIIT) and the Standardisation Administration of China (SAC). Although published on 31 December 2025, it officially entered into force on 1 July 2026.
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Standardised Battery Health Measurement
The regulation introduces a new metric known as the State of Available Energy (SOCE), which measures the remaining usable energy of a traction battery relative to its original condition.
Unlike the commonly displayed State of Charge (SOC), which indicates the battery’s current charge level, SOCE reflects long-term battery ageing and the proportion of the battery’s original usable capacity that remains available.
Under the new standard, the difference between the SOCE value displayed to drivers and the battery’s physically measured capacity must not exceed 5%.
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The requirement establishes, for the first time, a nationally recognised benchmark for battery health reporting in electric vehicles.
Minimum Capacity Requirements
The standard also sets minimum battery capacity retention targets based on vehicle age and mileage.
Electric vehicle batteries should retain at least:
- 82% of their original available energy after five years or 100,000 kilometres.
- 75% after eight years or 160,000 kilometres.
- 70% after ten years or 200,000 kilometres.
These thresholds are intended to provide consumers and manufacturers with consistent reference points for evaluating long-term battery performance.
Virtual Kilometres Included
The framework also introduces the concept of virtual kilometres, accounting for electricity consumed while the vehicle is stationary.
Energy used by systems such as air conditioning or auxiliary electronics is converted into an equivalent driving distance to provide a more comprehensive assessment of battery usage.
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The standard requires displayed virtual kilometre values to remain within a 3% margin of the measured value.
Implications for the EV Market
The technical framework was developed under the leadership of battery expert Yu Yang and is intended to make battery degradation more transparent through standardised and traceable testing methods.
Industry observers believe the new battery health metrics could improve confidence in used electric vehicles by providing more reliable information on battery condition.
The standard is also expected to influence residual value assessments, warranty management and future vehicle development strategies.
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Although GB/T 46991.1-2025 is classified as a recommended national standard rather than a mandatory regulation, such standards frequently become de facto industry benchmarks in China. Manufacturers that choose not to adopt MIIT-backed recommendations may face reduced competitiveness in areas such as government procurement programmes, subsidy eligibility and consumer confidence.
Source: CarNewsChina
