GB/T 46991.1-2025: China's EV battery durability standard explained

© A. Krivonosov

The health of an EV traction battery is no longer supposed to be a number nobody can verify. China’s GB/T 46991.1-2025 standard sets a tolerance between the SOCE value shown to the owner and the physically measured result, and it lays out durability benchmarks after 5, 8 and 10 years of use.

According to CCTV News, the allowed discrepancy is capped at 5%. The text of the standard itself defines it as the difference between the onboard SOCE reading and the measured value, so the rule is mainly about preventing the displayed battery condition from being overstated by more than five percentage points. China’s official standards database confirms the document was published on December 31, 2025, and took effect on July 1, 2026.

SOCE should not be confused with the familiar SOC. SOC shows how much energy is left until the next charge, while SOCE compares the usable energy of an aged battery with that of a new one. Manufacturers must give owners at least one way to check this value — through the instrument cluster, the infotainment system or a mobile app. The figure must also be accessible through the OBD diagnostic port.

For passenger EVs and plug-in hybrids in categories M1 and M2, three checkpoints apply: at least 82% of the original usable energy by five years or 100,000 km, 75% by eight years or 160,000 km, and 70% by ten years or 200,000 km — whichever comes first.

Short-range EVs with a certified range of no more than 220 km get softer thresholds: 80%, 72% and 67% respectively. Light commercial N1 vehicles get their own scale too — 80%, 70% and 65%. This detail is missing from the original press coverage but is spelled out directly in the standard.

Energy spent on things other than driving is tracked separately. Power drawn by V2L, V2H, V2G and other external-supply functions is converted into “virtual mileage.” The margin of error for that calculation cannot exceed 3%, so battery discharge used to power a home or appliances doesn’t disappear from the usage history.

The new document complements China’s mandatory fire-safety standard GB 38031-2025, which SPEEDME.RU covered earlier: one governs the risk of fire and thermal runaway, the other governs durability and the reliability of battery data. Real-world degradation still depends heavily on chemistry, temperature and charging habits — something also visible in the collected data on Tesla Model 3 and Model Y batteries.

GB/T 46991.1-2025 remains a recommended, not mandatory, standard. The 82% threshold is not a promise of a free warranty replacement, and falling below it does not by itself ban further use or trigger a mandatory recall. For buyers of used Chinese EVs, the document’s real value is elsewhere: battery condition can now be compared using a single methodology, not just the range shown on the dashboard.