Battery Passport Lifecycle

Chain of responsibility

The Battery Regulation defines a clear chain of responsibility. The key insight: the manufacturer/importer who placed the battery on the EU market remains legally responsible for the passport throughout the battery's entire first life — even after selling it.

The consumer never has write access. They can only read public data via QR scan.

Regulatory basis

Article 77(4): The economic operator must "ensure that the information in the battery passport is accurate, complete and up-to-date."

Recital 94: "the responsibility of compliance with the provisions for the battery passport should lie with the economic operator placing the battery on the market" — this persists even when the battery is in someone else's hands.

Article 3(22): An "economic operator" includes the manufacturer, importer, distributor, or any person placing the battery on the market. But only the manufacturer or importer can "place on the market" (Recital 10).

The lifecycle

stateDiagram-v2
    [*] --> Manufacturing: Manufacturer creates passport
    Manufacturing --> FirstLife: Sold to OEM / consumer
    FirstLife --> FirstLife: BMS updates SoH (daily)
    FirstLife --> FirstLife: Service / maintenance events
    FirstLife --> Repurposing: Battery removed from vehicle
    FirstLife --> Waste: Declared end-of-life
    Repurposing --> SecondLife: NEW passport by NEW operator
    SecondLife --> SecondLife: BMS updates SoH
    SecondLife --> Waste: End of second life
    Waste --> Recycled: Material recovery
    Recycled --> [*]: Passport ceases to exist

    note right of FirstLife
        Original manufacturer/importer
        remains responsible throughout
    end note

    note right of SecondLife
        New economic operator
        is now responsible
    end note

Responsibility at each stage

Stage	Responsible party	What they do
Manufacturing	Manufacturer	Creates passport, assigns unique ID, affixes QR code
First life (in use)	Original manufacturer/importer	Keeps data accurate and up-to-date via BMS backend
Service / maintenance	Manufacturer (can delegate)	Authorized service providers update on manufacturer's behalf
Repurposing	New economic operator	Creates a new passport linked to the original
Declared waste	Producer responsibility org / waste operator	Responsibility transfers
Recycling	Recycler	Passport ceases to exist (Art. 77(6b))

Key rules

• Delegation, not transfer: The manufacturer can authorize another operator "to act on their behalf" (Art. 77(4)), but legal responsibility stays with the manufacturer.
• Repurposing = new product: A repurposed battery is legally a new product and requires a new passport linked to the original (Art. 77(6a)).
• Consumer = read, no write: Consumers are in the "general public" access group. No write access — but the passport exists primarily for them. A buyer evaluating a used EV battery needs to verify SoH, cycle count, maintenance history, and carbon footprint to make an informed purchasing decision. The blockchain anchoring means this data is tamper-evident: the manufacturer cannot retroactively inflate SoH numbers to sell a degraded battery.
• BMS feeds the passport: The BMS records SoH/cycle data. The manufacturer's backend processes it and publishes to the passport. Recital 46: data should be "at least updated daily."
• End: "A battery passport shall cease to exist after the battery has been recycled" (Art. 77(6b)).

Cardano architecture

The write side is manufacturer-operated. But the read side is where the value lives — the passport serves multiple audiences making real decisions:

Actor	What they need from the passport	Why blockchain matters
Used battery buyer	SoH, cycle count, maintenance history, remaining lifetime estimate	Manufacturer can't inflate numbers — data was anchored at a specific time
Repurposing operator	Detailed SoH curves, material composition, disassembly instructions	Verifiable provenance for second-life assessment
Insurance company	Battery condition, conformity declarations	Tamper-evident condition records
Fleet manager	SoH across all vehicles, predictive maintenance	Trusted data from multiple manufacturers in one view
Market surveillance	Due diligence, conformity, carbon footprint	Immutable audit trail
Recycler	Chemistry, hazardous substances, disassembly	Accurate material composition for safe processing

Actors and their interfaces

graph TD
    subgraph "Manufacturer's Infrastructure"
        A[BMS Telemetry Receiver]
        B[Passport Backend Service]
        C[Cardano Signing Keys]
        A -->|SoH, cycles, temp| B
        B -->|update hash| C
    end

    subgraph "Cardano L1"
        D[CIP-68 Reference NFT]
        E[Event Log tx history]
        C -->|tx with new datum hash| D
        C -->|batch Merkle root| E
    end

    subgraph "Off-chain Storage"
        F[IPFS / Cloud]
        B -->|full passport JSON-LD| F
    end

    G[Consumer] -->|scan QR| H[Resolver API]
    H -->|query UTxO| D
    H -->|fetch data| F
    H -->|public tier only| G

    I[Authority] -->|authenticated request| H
    H -->|full data| I

    J[Recycler / Repairer] -->|role token auth| H
    H -->|restricted tier| J

    K[Battery BMS] -->|telemetry stream| A

Who holds what

Actor	Holds	Cardano interaction
Manufacturer	CIP-68 user token + signing keys	Submits update transactions, manages off-chain data
Consumer	Nothing	Scans QR → resolver API → reads public data
Service provider	Delegated signing key or role token	Submits updates on manufacturer's behalf
New operator (repurposing)	New CIP-68 user token (new passport)	Mints new passport linked to original
Authority	Authority credentials	Reads all data via API (no on-chain interaction needed)
Recycler	Role token	Reads restricted data, marks passport as ceased

Transfer on repurposing

When a battery is repurposed, it becomes a new product. On Cardano:

sequenceDiagram
    participant M as Original Manufacturer
    participant N as New Operator
    participant C as Cardano L1

    M->>C: Update original passport status → "end of first life"
    Note over C: Original CIP-68 datum updated

    N->>C: Mint NEW CIP-68 token (new passport)
    Note over C: New datum contains link to original passport (policy ID + token name)

    N->>C: Ongoing updates to new passport
    Note over C: New operator is now responsible

The original passport remains on-chain (immutable history). The new passport references it, preserving the full chain of custody.

Passport cessation on recycling

When the battery is recycled, the recycler (holding a DPP_RECYCLER role token) submits a final transaction:

• Updates the CIP-68 datum status to Waste / Recycled
• Records material recovery data in the event log
• The passport is no longer "active" but the on-chain record persists as historical evidence

Revocation and invalidation

The regulation defines one cessation trigger: recycling (Art. 77(6b)). But other invalidation scenarios exist that the regulation does not explicitly address:

Scenario	Trigger	Proposed on-chain action
Recycling	Battery has been recycled	Status → Recycled, passport ceases (Art. 77(6b))
Recall	Safety defect discovered	Authority marks passport with recall flag
Fraud detection	Falsified data discovered	Authority revokes passport validity
Manufacturer insolvency	Company ceases to exist	Escrow/backup provider takes over (ESPR Art. 11)
BMS key compromise	Secure element private key leaked	Manufacturer updates BMS public key in datum, old readings flagged
Duplicate / counterfeit	Same battery ID on multiple passports	Authority flags duplicates via market surveillance

On Cardano, revocation is a datum update: a revoked or recalled flag set by the appropriate role token holder (authority or manufacturer). The validator enforces that only authorized actors can set these flags. Revoked passports remain on-chain as historical evidence but are marked as invalid for current use.

No formal revocation registry in regulation

The Battery Regulation does not define a revocation mechanism beyond cessation on recycling. The scenarios above are implementation-level provisions for situations the regulation doesn't explicitly address. A future delegated act or implementing act may formalize revocation requirements.

Data flow: BMS to passport (open problem)

The regulation does not specify this

Article 14 requires the BMS to contain SoH data. Article 77 requires the passport to have SoH data. How data moves from one to the other is completely unspecified. See Passport State for the full analysis.

The data path depends entirely on the battery category and the manufacturer's infrastructure:

Category	Realistic data path
Connected EVs	BMS → telematics → manufacturer cloud → passport
Non-connected EVs	BMS → diagnostic port → service visit → manual upload
E-bikes / scooters	BMS → Bluetooth/app? → manufacturer? → passport (unclear)
Industrial batteries	BMS → on-site diagnostic tool → manual upload

For non-connected batteries, the passport may only be updated at discrete events (service visits, inspections, point of sale) rather than continuously.

On-chain anchoring cadence

The on-chain datum only needs to be updated when the hash of the off-chain data changes. A practical cadence depends on how often data actually reaches the passport — which varies by category:

Data type	Source	Realistic cadence	On-chain?
SoH snapshot	BMS (however extracted)	Per data availability event	Hash anchor on-chain, full data off-chain
Cycle count	BMS	With SoH update	In off-chain data
Maintenance event	Service provider	Per visit	Event log batch
Ownership change	Sale transaction	Per sale	Datum update
Status change	Operator decision	Per event	Datum update