Who owns each battery-passport data field?

The EU Battery Regulation makes one party legally answerable for the battery passport: the economic operator who places the battery on the EU market. Article 77 is unambiguous — that operator must ensure the passport is accurate, up to date, and complete. But almost none of the data in an Annex XIII passport originates with that operator. It comes from cathode suppliers, cell manufacturers, carbon-footprint verifiers, recyclers, and logistics partners scattered across three continents.

That gap — between who is liable for the data and who actually holds it — is the part of battery-passport compliance that catches teams out. It is not a technology problem and it is not solved by buying a database. It is a data-ownership problem, and it has to be answered field by field before February 2027.

This article walks the Annex XIII field set and asks, for each block, a single question: who in your supply chain is the source of truth, and what happens when they are slow, wrong, or silent?

The liability sits in one place. The data does not.

Start with the legal fact, because it frames everything else. The operator placing the battery on the market holds the passport obligation. The regulation does allow that operator to authorise another party, in writing, to act on its behalf — which is the basis on which a service provider can run the infrastructure. But authorisation moves the work, not the liability. If the cobalt due-diligence figure is wrong, it is the economic operator that answers to a market-surveillance authority, not the supplier who provided the number.

So when you map your passport fields, you are really mapping your exposure. Every field sourced from outside your organisation is a field where you are liable for data you did not generate. The job is to make that dependency explicit, assign an internal owner to chase each external source, and keep an audit trail of what was supplied, by whom, and when.

Block 1 — Identity and the responsible operator

These are the fields you genuinely own: battery model, manufacturer identity, the responsible economic operator, place and date of manufacture, battery category and weight. There is no ambiguity here and no external dependency. If your passport is incomplete on identity fields, that is an internal process gap, not a supply-chain one.

The one trap is the "responsible economic operator" field itself. This field names the party answerable to EU market-surveillance authorities for the passport — and who that is depends on how the battery reaches the market. For a maker established in the EU it is usually the manufacturer itself; for a battery made outside the EU, whether in the UK, the US, China, Korea or anywhere else, it is the importer or an EU-based authorised representative who carries that role. The common requirement is that the named operator must be reachable within the EU's enforcement reach. Get that legal entity right before you get anything else right.

Block 2 — Composition and materials

Cathode active material, anode, electrolyte, critical raw materials, hazardous substances. This is the first block where ownership leaves your building. The chemistry is defined by your cell supplier; the critical-raw-material content traces back to cathode and refining partners; the hazardous-substance declarations depend on safety-data sheets that may themselves be out of date.

The owner here is procurement, not compliance — because the leverage to get accurate composition data is contractual. If your supply agreements do not already require suppliers to provide Annex XIII-grade composition data on a defined cadence, that is the single most valuable contract amendment you can make this year.

Block 3 — Carbon footprint

The carbon-footprint declaration is mandatory now for EV and industrial cells, and it is the field people most often get wrong — because they attach a PDF. Annex XIII does not want a PDF. It wants the per-kWh figure, the lifecycle-stage split, the methodology, and the verifier, as structured data. A carbon-footprint study sitting in a shared drive is not a passport field; it is raw material for one.

Ownership is split: your sustainability team commissions the study, a notified or third-party verifier signs it, and the structured figures have to land in the passport in the right shape. The failure mode is a verified study that never gets transcribed into the structured fields — fully compliant work, non-compliant passport.

Block 4 — Supply-chain due diligence

This is the block that exposes the most organisations, because it reaches furthest down the chain. Due-diligence data on cobalt, lithium, nickel, and natural graphite traces to mine and refiner level, often through several intermediaries. For operators above the turnover threshold, a notified body verifies that the due-diligence obligations are met.

No single internal team owns this. It is a coordination problem across procurement, sustainability, and legal, dependent on suppliers who may have no contractual reason to respond quickly. The practical answer is to treat each due-diligence field as a standing data request with a named owner and a deadline, not a once-a-year scramble.

Block 5 — Performance, durability, and state of health

Rated capacity, expected lifetime, and — for the live passport — state-of-health data that updates over the battery's life. The static figures come from your engineering and test data and are largely under your control. The dynamic data is different: it implies a live link between fielded batteries and the passport, which is an architecture decision, not a data-entry one.

This is the block that quietly forces the build-versus-buy question. Maintaining live state-of-health updates against thousands of item-level passports is a standing infrastructure obligation, not a one-time data-entry task — which is why a spreadsheet that works for a handful of records stops working at scale.

Block 6 — Recycled content and end-of-life

Recycled-content percentages for cobalt, lithium, and nickel, plus end-of-life and collection information. Recycled-content figures trace back to your cell and material suppliers; end-of-life information may involve recyclers and producer-responsibility organisations you have not yet contracted with in 2026.

The ownership question here is uncomfortable because some of these relationships do not exist yet. The field cannot be populated from a supplier you have not appointed. Mapping this block early surfaces the partnerships you still need to put in place.

What the field-by-field map gives you

Walk all six blocks and a pattern appears. Roughly a third of the Annex XIII field set is genuinely yours; the rest is owned by parties you have to chase, contract with, or build live links to. The compliance risk is concentrated almost entirely in the fields you do not own — which is precisely why "we'll handle the passport internally with a spreadsheet" tends to fail. The spreadsheet is fine; the supplier who never returns the cobalt figure is the problem.

A practical readiness exercise looks like this: list every Annex XIII field, mark each as internal or external, name the source for every external field, name the internal owner who chases it, and record the cadence at which it must refresh. The fields with no named source are your gaps. The fields with no internal owner are your future fire drills.

Build or buy — and where the line sits

Whichever route you take, one thing does not move: the regulation keeps the liability with the economic operator. No service provider takes that on, and any that claims to is misreading Article 77. What infrastructure — built or bought — has to do is the same in either case: capture each field in the correct structured shape, validate it against the Annex XIII schema before it is committed rather than mapping it loosely afterward, keep an audit trail of exactly what was supplied and when, and serve the public passport when a QR code is scanned at customs.

That is the useful way to frame the decision. You own the data and the liability regardless; the question is only who runs the validation, the audit trail, and the uptime. The field-by-field ownership map is what makes that decision legible — and it is the first thing worth doing, whether you go on to build or to buy.