China’s new EV battery standard limits SOCE overstatement to five percentage points

A recommended standard creates a common benchmark

GB/T 46991.1-2025 was published on 31 December 2025 and took effect on 1 July 2026. It is a recommended national standard rather than a mandatory GB regulation.

It covers battery-electric vehicles and plug-in hybrid electric vehicles. Its scope includes N1 vehicles and M1 and M2 vehicles with a maximum vehicle mass of no more than 3,500 kg. M1 vehicles above that limit may use the document as a reference.

Its recommended status does not make it insignificant. The standard gives manufacturers and testing organisations a common method for assessing usable battery energy over a vehicle’s service life.

It does not, however, create an automatic right to a replacement battery whenever a vehicle falls below one of its thresholds. Nor does it replace the manufacturer’s warranty terms.

SOCE is not the same as state of charge

SOCE stands for State of Certified Energy. It describes the battery’s remaining usable-energy performance at a particular point in the vehicle’s life, expressed relative to the certified usable energy established when the vehicle was new.

The vehicle provides an on-board SOCE estimate. For verification, a measured SOCE is calculated from the usable battery energy obtained through the prescribed test procedure and compared with the certified reference value.

SOCE does not show how fully charged the battery is at that moment. That is the role of SOC, or state of charge. An aged battery may be charged to 100% SOC while having an SOCE of only 82%. In that case, a fully charged battery can deliver roughly 82% of its certified initial usable energy under the specified test conditions.

SOCE is not identical to the broader concept of SOH, or state of health, either. Manufacturers may calculate SOH using energy capacity, internal resistance, charging performance, temperatures and other parameters. SOCE has a narrower focus: retained usable energy measured against a certified starting value.

Under the standard, the vehicle must monitor and update both SOCE and SOCR — State of Certified Range — over its service life. The latest on-board SOCE and SOCR values must be available through the vehicle’s OBD interface, and the user must have at least one way to view the SOCE figure. That may be through the instrument display, infotainment system or a mobile app.

The standard mainly prevents an over-optimistic reading

The accuracy requirement states that the on-board SOCE estimate minus the measured SOCE must not exceed five percentage points.

In practical terms, it primarily limits overstatement. If the prescribed test measures an SOCE of 80%, the vehicle may not display more than 85%. The rule should not be described as a symmetrical ±5% accuracy tolerance because it does not impose an equivalent limit on an under-reading.

The distinction between percentages and percentage points matters. If the measured SOCE is 80% and the vehicle displays 85%, the difference is five percentage points, while the relative error is 6.25%.

Minimum battery retention depends on vehicle category

The standard uses three age-and-mileage milestones, with whichever limit is reached first determining the applicable stage.

For M1 and M2 plug-in hybrids, and for M1 and M2 battery-electric vehicles with more than 220 km of certified range, the minimum SOCE thresholds are:

- 82% at five years or 100,000 km;

- 75% at eight years or 160,000 km;

- 70% at ten years or 200,000 km.

For M1 and M2 battery-electric vehicles with a certified range of no more than 220 km, the thresholds are lower:

- 80% at five years or 100,000 km;

- 72% at eight years or 160,000 km;

- 67% at ten years or 200,000 km.

The corresponding thresholds for N1 light commercial vehicles are 80%, 70% and 65%.

For example, an M1 electric car with 75 kWh of certified usable energy would need to retain at least 61.5 kWh at the first milestone under the standard thresholds. At the second milestone, it would need at least 56.25 kWh, and at the third, at least 52.5 kWh.

Those figures do not mean that real-world range will remain in exactly the same proportion. Energy consumption still depends on temperature, speed, tyres, road conditions and the use of auxiliary systems.

China’s standard thresholds exceed the Euro 7 minimum for M1 cars

Euro 7 sets minimum usable-energy retention for M1 battery-electric vehicles and plug-in hybrids at 80% up to five years or 100,000 km, and 72% beyond that point and up to eight years or 160,000 km.

The main Chinese M1 thresholds are 82% and 75% at the same milestones — two and three percentage points higher respectively. The Chinese standard also adds a third milestone at ten years or 200,000 km, with a minimum SOCE of 70%.

A direct comparison still requires legal context. China’s GB/T 46991.1-2025 is a recommended technical standard, whereas Euro 7 is a binding European Union type-approval regulation.

Euro 7 applies to new M1 and N1 vehicle types from 29 November 2026 and to all new vehicles in those categories from 29 November 2027.

The effect could extend to the used-car market

The standard’s greatest value may lie not only in its durability percentages but in the common SOCE methodology behind them. Where the standard is adopted, it allows vehicles from different manufacturers to be assessed on a more consistent basis and makes it harder to present a battery as healthier than the prescribed test indicates.

For a used-EV buyer, a verifiable SOCE figure could become as important as the service history of a combustion-engined car. It cannot replace a comprehensive battery inspection, but it can provide a quick, standardised indication of how much certified usable energy remains.

The Chinese standard does not automatically alter the warranty of a vehicle sold in Estonia or elsewhere in Europe. Manufacturers may, however, use the same underlying battery-management and diagnostic architecture across several markets. More accurate SOCE monitoring developed for China could therefore eventually appear in European vehicle software, workshop diagnostics and used-car condition reports.