Catena-X, Gaia-X and the interoperability question: will your battery passport survive the hand-off?

A battery placed on the EU market on 18 February 2027 will carry its digital passport into the 2040s, through three or four changes of ownership along the way. The OEM that issues the record will not be the fleet that operates the pack, the storage operator that repurposes it, or the recycler that dismantles it, yet Regulation 2023/1542 expects all of them to read and update the same per-unit record. Whether they can depends on a question buyers rarely put to their passport vendor: does this passport work outside your platform?

Why do battery passports fail at the hand-off?

The passport earns its keep at company boundaries. The moments that justify its existence are transfers: the OEM sells or leases packs to a fleet, the fleet retires a pack to a second-life operator, the operator eventually sends it to a recycler. At each transfer the reader sits in a different company, running different software, with no contractual relationship to the passport's issuer.

A passport that lives only inside one vendor's SaaS behaves like a walled garden at exactly those moments. A recycler receiving packs from fifteen brands cannot operate fifteen portals with fifteen logins and fifteen data formats; intake triage reverts to manual inspection, which is the problem the passport was meant to remove. Data-sharing terms collapse back into bilateral NDAs negotiated pack by pack. And on a 15 to 20 year asset life, there is a fair chance the original vendor no longer exists when the record matters most.

The regulation anticipates this. Its access tiers grant read rights to persons with a legitimate interest, explicitly including recyclers and second-life operators, and its data must stay available through the battery's whole life. Both assumptions only hold if the passport is readable independently of any single company's IT estate.

What is Catena-X?

Catena-X is the automotive industry's data space, started in 2021 by a group of German automotive and software companies (BMW, Mercedes-Benz and SAP among the founders) and run today by a member association of several hundred companies. It is deliberately not a platform. It is three things:

• A standards library. Published specifications define each data-exchange use case. For passports, standard CX-0143 (Use Case Circular Economy: Digital Product Passport) covers the battery passport, including how a passport is found, requested and returned.
• Open-source reference software. The Eclipse Tractus-X project, hosted by the Eclipse Foundation, provides working implementations, so no single company owns the code that moves the data.
• A connector architecture. Each participant runs its own Eclipse Dataspace Components connector (EDC), the gateway through which it offers data to others and consumes theirs. Exchange is peer to peer between two connectors; no central operator sees the payload.

Semantics are standardised too. Products get a digital twin based on the Asset Administration Shell, the industrial digital-twin standard, and the passport's attributes follow published aspect models, so "state of health" or "recycled cobalt share" means the same thing to every participant. In practice, a recycler scans the QR code on an incoming pack, resolves it to the pack's digital twin, negotiates access through its own connector and reads the attributes its role permits. The first Catena-X certified battery-passport solutions are already on the market, which means the exchange path is tested, not theoretical.

What is Gaia-X, and how does it relate?

Gaia-X is not automotive and not a network you join to move data. It is a European non-profit association, now over 350 members, that defines the trust layer underneath federated data infrastructure: how participants prove who they are, how services declare where data is processed and under which jurisdiction, and how those claims are verified by machines rather than lawyers.

Its Trust Framework, whose release 3.0 "Danube" arrived in November 2025, automates those compliance checks, and a network of Gaia-X Digital Clearing Houses acts as verification nodes: they check a participant's credentials before it enters a data space. More than fifteen operational European data spaces build on these rules.

The relationship is layered. Gaia-X supplies cross-sector rules of trust and identity; Catena-X applies them to automotive use cases. For batteries the cross-sector part is not optional: a pack's life runs through automotive, then energy (stationary storage is an energy-sector business), then recycling. Credentials that are recognised across data spaces are what let a passport follow the pack across those sector boundaries.

What does a "data space" mean in practice?

Strip the vocabulary away and a data space is a small set of concrete mechanics, all of which contrast with handing partners an API key to your platform:

• Data stays at the source. There is no central lake. Each company publishes offers in a catalogue through its connector; the data itself moves only when a specific request is granted.
• Participants are verified. Every request arrives from a credentialed identity, so the provider knows exactly which legal entity is asking, and can answer differently per requester.
• Contracts are negotiated per exchange. Connectors exchange machine-readable offers and acceptances before any transfer, and the agreement is logged. Every read has a paper trail.
• Usage policies travel with the data. The provider attaches conditions, for example "for recycling compliance only, no onward sharing", that are expressed in machine-readable form and enforceable, rather than buried in a PDF signed two owners ago.

This is what "sovereign data exchange" means: the provider keeps control per data asset, per partner and per purpose. For batteries it directly answers the IP fear that keeps chemistry data locked up. An OEM can expose exact composition and disassembly data to the recycler that holds the pack, under a usage policy, without publishing it to the market.

What should you demand from a passport vendor?

Interoperability claims are cheap; a slide with both logos proves nothing. A buyer evaluating passport software for the 2027 deadline should ask for specifics:

• Standard semantic models. Passport attributes mapped to the published aspect models and to Annex XIII, not a proprietary JSON schema with an export button.
• A data-space connector, not a vendor API. An EDC-compatible endpoint, so partners fetch passports through their own data-space membership instead of accounts on your vendor's portal.
• Identifiers that outlive the vendor. The passport's unique identifier must remain resolvable per the regulation's rules even if the vendor's domain names disappear.
• Access tiers as configuration. Public, legitimate-interest and authority views implemented as the regulation defines them, demonstrable per role.
• Usage-policy support. The ability to attach machine-readable conditions to sensitive attributes such as chemistry and disassembly data, with an audit log of every access.
• A documented exit. Full machine-readable export including the update history, and a handover procedure to a successor system, tested rather than promised.
• Proof over promises. Certification against the relevant Catena-X standards, or a demonstrated live exchange with a certified counterpart.

A vendor that meets this list can lose you as a customer without losing your batteries' history. That is the correct test.

Conclusion: interoperability is the product

A battery passport is a shared record among companies that do not fully trust each other and were never going to buy the same software. If it cannot cross a company boundary carrying its meaning, its access rules and its audit trail with it, it is a compliance PDF wearing a QR code. Data spaces exist to make that crossing routine: verified identity, negotiated contract, usage policy, transfer. Buy passports, and passport software, accordingly.

Passoria is built for the hand-off: passports structured to Annex XIII and interoperable with Catena-X and Gaia-X data spaces, so fleets, buyers and recyclers read them through their own connectors. To test the exchange with your own partners before the 2027 deadline, our pilot program is open to a limited number of manufacturers, resellers and recyclers.