The 2027 battery passport: what changes, who's responsible, and why your battery should already know

Until now, in the eyes of EU law, a residential battery was little more than an electrical product: meet some safety minimums, carry the CE marking, and not much else. From 18 February 2027, this changes completely. Every stationary battery over 2 kWh placed on the European Union market must have a digital passport: an electronic record, accessible via a QR code, that travels with the battery throughout its entire life.

It is not just another label. It is a conceptual shift about what a battery is: it stops being an opaque box that someone sells you and nobody ever hears about again, and becomes a product with digital identity, verifiable health and history. In this article we explain what the passport is, what it requires and from whom, what is already mandatory today (this will surprise you), and why at SolarBox we have been working as if this law already existed for years.

1. What exactly is a battery passport

The best analogy is the digital ID of a person, but for a battery. It is a structured record, linked to a specific battery via a QR code printed or engraved on the product, that contains information kept up to date throughout the entire useful life.

What is inside? Broadly, four families of data:

• Identity and composition. Manufacturer, model, serial number, chemistry, materials, recycled content.
• Environmental footprint. Manufacturing carbon footprint, recycling and end-of-life information.
• Performance and durability. Nominal capacity, expected life in cycles and years, efficiency, internal resistance.
• Health and history. The battery's state of health (SoH) and remaining useful life.

One important nuance: the passport is not equally transparent to everyone. It works with tiered access. The end customer and the general public see some data (sustainability, instructions, safety); recyclers and second-life operators see other data (disassembly, health); and commercially sensitive information stays protected, accessible only to authorities and notified bodies. The law seeks transparency, not exposing each manufacturer's know-how.

2. What you may not know: most of this is already mandatory

Here comes the surprise. When people talk about the Battery Regulation, everyone looks at the 2027 date as if that were the starting point. It isn't. Regulation (EU) 2023/1542 entered into force in 2023 and applies in phases. For stationary systems above 2 kWh — that is, practically any serious residential solar battery — two key obligations have been in force since 18 August 2024:

Battery safety. Stationary storage systems must already prove, with technical documentation, that they have passed specific safety tests: fire behaviour, explosion, thermal propagation between cells, and mitigation strategies. A generic electrical test is not enough — these are tests designed specifically for batteries.

Health data at the BMS. This is where we want you to pay attention. The Regulation already requires that the battery management system (BMS) contain up-to-date data on the parameters determining SoH and expected lifetime, and that this data be accessible. In other words: the law already requires your battery to know its state of health and to be able to tell you.

And what happens with most batteries on the market? They comply with the minimum letter — the BMS "has" the data — but nobody collects it, stores it or analyses it over the years. The battery knows its health right now, but there's no history, no follow-up, no learning.

At SolarBox we decided to do exactly the opposite. Our fleet manager continuously logs voltage, current and temperature cell-by-cell of installed batteries, and computes SoH across months and years. If you want to see how this translates into real field data, we cover it in depth in our article When to replace a solar battery: cycles, SoH and field data. What the law will require everyone to have solved, we have had running for some time. It is not an advantage we invented for 2027: it is an obligation already in force that we comply with while much of the sector does not yet.

We have even gone one step further. Firmware version v3.10.13 on our batteries, deployed in May 2026 to the pilot installation, already embeds a passport_uid field: a unique identifier embedded in the management system itself, which will be the backbone of the digital passport when the law requires it. When the passport QR becomes mandatory in February 2027, our batteries will already know how to answer "this is me, here's my history" without needing a retrofit. The data–history–identity chain is already wired up — only the QR remains to be printed.

3. Who's responsible: manufacturer or installer?

This is the question that worries installers most, and the answer is clear and reassuring.

The obligation falls on the economic operator who places the battery on the market — i.e. whoever manufactures it and sells it under their brand. They are the ones who must generate the passport, draft the declaration of conformity, do the CE marking and assume product liability. In the case of a SolarBox battery, that operator is us. Even if the cells are manufactured by a third party, the complete system is designed, assembled and sold by us under the SolarBox brand. The passport responsibility is ours.

The installer, when they are a third party, acts as a distributor. They have duties, but light ones: verify the battery arrives with the correct CE marking, passport QR and labelling, that instructions in the customer's language accompany it, and not place non-conforming products. What they do not have to do is generate any passport, draft any declarations or build any data infrastructure.

This is the practical difference for an installer: selling a SolarBox battery means selling a product that already arrives with the hard part solved. You verify; we carry the regulatory weight. The question facing 2027 isn't whether it affects you — it does — but who has it solved for you before it arrives.

4. The calendar, without alarm

It's worth separating what is firm from what is still being defined, because the press often mixes them up and generates unnecessary fear.

• What's already in force (since 2024): stationary system safety and BMS health data, as we've seen.
• What arrives in 2027: the digital passport, firm for 18 February. That date hasn't moved and it is not prudent to bet that it will be delayed.
• What comes after: some technical requirements specific to stationary systems — like the detailed carbon footprint methodology — have a later calendar, tied to delegated acts the Commission still has to publish. So the passport is firm in 2027; some technical annexes will mature later.
• What does NOT affect us: the most bureaucratically heavy part — supply chain due diligence obligations — only applies to operators with €40 million turnover or more. For a manufacturer our size, that burden falls outside the scope.

The underlying message is anticipation, not alarm. This is coming, it's certain, and the smart work is to do it during 2026, not to wait for the last quarter.

5. Why this protects you (and isn't just "compliance")

So far this might sound like the passport is just another bureaucratic burden. It isn't. For the end customer, it is above all a protection.

Verifiable health = safe investment. The number-one fear of someone buying a battery is "what if it dies prematurely?". When the battery's health is a measured and recorded data point, you stop depending on a commercial promise: you can check how it actually ages. A battery with verifiable health is an asset, not a bet.

Traceability = transparency. You know where the materials come from, what footprint they have, and how they should be handled at end of life. For someone who values the environmental coherence of their investment, this matters.

Second-life value. When a battery reaches the end of its first life (typically at 80% state of health), it isn't waste: it has residual value. The Regulation itself recognises this and requires a new passport when a battery is repurposed. Your investment doesn't vanish; it transforms.

And here we open two reflections we'll develop in upcoming articles. The first: a monitored battery with certified health is the entry door to new flexibility markets, where small aggregated installations can contribute services to the grid. The second: the chemistry shift toward LFP and, beyond, sodium-ion, with much longer lifetimes, forces us to rethink warranty and buyback — because when a battery can last decades, the long-term value conversation changes entirely.

Closing

18 February 2027 will not catch us improvising. While much of the sector looks at the date with concern, we have been working for years with the logic this law enshrines: that a battery should know how it is, should be able to prove it, and the manufacturer should answer for it throughout its life. The fleet manager we already have running is not a marketing add-on: it is, literally, the infrastructure the battery passport will require.