The passport problem in second-life batteries.
A second-life battery passport is the new battery passport that the EU Battery Regulation requires when a battery is prepared for re-use, repurposed or remanufactured, linked to the passport of the original battery.
Second-life battery projects harvest modules from many retired EV packs and rebuild them into storage systems. Article 77(7) requires the rebuilt battery's passport to link back to every original passport. That is a genealogy requirement — and it cannot be met at scale if identity only exists at pack level, because the pack identity dies when the pack is opened.
Battery passport for second life, in three facts.
Reg. (EU) 2023/1542 · Article 77(7) · a repurposed battery needs a new passport linked to the passport(s) of the original batteries.
When a battery is prepared for re-use, repurposed or remanufactured, it needs a new battery passport linked to the original one (Article 77(7)).
Source: Regulation (EU) 2023/1542From 18 February 2027 every light-means-of-transport battery, every EV battery and every industrial battery over 2 kWh placed on the EU market needs a battery passport (Regulation (EU) 2023/1542, Article 77).
Source: Regulation (EU) 2023/1542The Commission's battery passport guidance, updated on 21 August 2026, lists 71 data points and marks each one mandatory, voluntary, conditional or not yet required.
Source: Brussels Times, August 2026
A required outcome with unspecified means.
Linked passports on repurposing
Article 77(7): a battery put to a new use gets a new passport linked to the original battery passports — many-to-one genealogy when modules from several packs are combined.
Disassembly-ready documentation
Annex XIII expects exploded diagrams, disassembly sequences, and cell count and layout — information that presumes the parts inside are identifiable.
History that travels with the module
Cycle counts, incident history and operating conditions determine a module's second-life value. Without identity, that history is lost the day the pack is opened.
An answer insurers and buyers accept
Second-life economics run on state-of-health confidence. A module that can prove its history commands a price; an anonymous module sells as scrap.
The timeline, as it stands.
The obligation lands with the passport itself: batteries and their repurposed descendants placed on the market from 18 February 2027. Projects being engineered now decide whether compliance is possible later.
Three moves that de-risk the deadline.
Tag modules before packs retire
Genealogy must exist before disassembly. Module-level identity applied at manufacture — or at collection — is what makes the 77(7) linkage possible at all.
Record the teardown as events
Each harvest, test and rebuild step should append to the custody log, so the new passport's link to its ancestors is evidence, not assertion.
Design the new passport first
Before rebuilding, define what the storage system's passport must carry and where each field comes from. Retrofitting genealogy after assembly is guesswork.
Identity that survives the teardown.
Aeroz gives packs and modules chip-bound identities with custody written as EPCIS 2.0 events — so when a pack is opened, each module carries its own provable history into the rebuilt system, and the new passport's Article 77(7) linkage can be built from the log. This is the gap in the mandate: the law requires the outcome and specifies no means. We build the means.
Battery passport for second life, answered.
What exactly does Article 77(7) require?
That a battery prepared for re-use, repurposing or remanufacturing carries a new battery passport linked to the passport or passports of the original battery or batteries. The plural matters: rebuilt systems combine modules from many source packs.
Why can't pack-level marking satisfy it?
Because the pack's QR marks the pack. Once opened, its modules carry no mandated identity of their own — and a storage rack built from thirty packs' modules has no honest way to link back to thirty passports.
Does the regulation mandate module-level tagging?
No — that is the gap. The regulation requires the linked-passport outcome without specifying the means. Module-level identity is how the outcome becomes achievable at industrial scale.
Who carries this obligation?
The economic operator placing the repurposed battery on the EU market. Second-life integrators, remanufacturers and the OEMs supplying them all inherit a piece of the answer.
From the Aeroz blog
- What a QR code proves, and what an NFC chip proves
- The EU Missed Its Own Battery Passport Deadline. Yours Did Not Move.
More answers: EU battery passport questions in the compliance FAQ
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