Unlike chemistry or weight, a battery’s state of health changes throughout its life. The passport must reflect this dynamic data, which originates in the battery management system (BMS) rather than the factory record.
What counts as dynamic data
- State of health (remaining capacity relative to rated capacity).
- State of certified energy or remaining power capability.
- Number of full charge–discharge cycles and operating conditions.
- Current lifecycle status — in use, awaiting repurposing, recycled.
The Article 14 requirement
Article 14 requires that the data needed to determine state of health and remaining lifetime is held in the BMS and made accessible — read-only — to the natural or legal person who has legally purchased the battery, or a party acting on their behalf, including for repurposing.
How it flows into the passport
| Source | Data | Frequency |
|---|---|---|
| BMS | State of health, cycles, status | Updated over the battery’s life |
| Factory record | Rated capacity, chemistry, identifier | Fixed at manufacture |
| Operator | Repurposing and recycling events | On each lifecycle change |
Because dynamic data changes, the passport must accept updates without ever altering its public URL. Most of this data sits in the legitimate-interest tier, available to repairers, refurbishers and recyclers rather than the general public.
Frequently asked
Who can read the state-of-health data?
The legal owner of the battery and parties acting for them, plus those with a legitimate interest such as repairers and recyclers. It is not general public data.