What Does “Indelible” Actually Mean Under the EU Battery Regulation?
Indelible.
The Cambridge English Dictionary defines Indelible as “An indelible mark or substance is impossible to remove “
Article 13(7) of Regulation (EU) 2023/1542 states that labels and QR codes shall be “printed or engraved visibly, legibly and indelibly on the battery.” The word appears repeatedly throughout the regulation. The carbon footprint label must be indelible. The CE marking must be indelible. The QR code linking to the Battery Passport must be indelible. The separate collection symbol must be indelible.
The regulation does not, however, define what indelible means.
That is not an oversight. It is a deliberate legislative choice. And understanding why the drafters chose that word, and what it demands in practice, is the difference between genuine compliance and expensive wishful thinking.
Why the Regulation Uses This Word Deliberately
EU product legislation has a long history of using performance-based language rather than prescriptive technical requirements. The drafters of Regulation (EU) 2023/1542 did not specify laser marking. They did not ban adhesive labels. They wrote “indelible” and left it to manufacturers and market surveillance authorities to determine what that means in the context of each battery type, application and lifecycle.
The word comes from the Latin indelebilis, that which cannot be deleted or effaced. In the context of the Battery Regulation, the intent is clear even if the definition is not: the marking must survive the life of the battery. It must be readable at end of life. It must withstand the conditions the battery will encounter throughout its operational existence.
From 18 August 2026, batteries will need to display a comprehensive label including the place of manufacture, the battery category, weight and information on any hazardous substances other than mercury, cadmium and lead. From 18 February 2027, all electric vehicle and industrial batteries with a capacity greater than 2 kWh placed on the EU market must have a digital battery passport, accessible via a QR code, which must itself be printed or engraved on the battery.
Both deadlines are close. Neither gives manufacturers the luxury of a wait-and-see approach.
What Indelible Means in Practice: The Test That Matters
Think about where EV battery packs and industrial batteries actually go. They operate at high temperatures. They are exposed to vibration, chemicals, cleaning agents and moisture over years of service. In recycling facilities, they are handled roughly, sorted mechanically and processed at scale.
A marking is only truly indelible if it remains visible, legible and intact through all of that. The regulation is explicit that the purpose of the marking requirement is traceability across the battery’s entire lifecycle, including at the point of recycling and end-of-life processing.
Article 13 mandates that all batteries placed on the EU market must display clear, legible and indelible labels. Manufacturers must ensure labels remain visible throughout the battery’s lifetime under normal conditions of use.
That phrase, throughout the battery’s lifetime, is the operative standard. Not at the point of manufacture. Not for the first year of operation. Throughout the lifetime.
What Does Not Pass That Test
Adhesive labels are the most common current approach. Across the battery manufacturing industry, the standard practice for many producers has been to apply printed label stock to the battery casing, quick to apply, easy to change between production runs, familiar from decades of product labelling practice.
Under the EU Battery Regulation, adhesive labels face a fundamental problem: they can be removed.
More precisely: they will be removed. Adhesive labels peel. They lift at the corners in humid environments. They degrade under thermal cycling. Chemical exposure, including the cleaning agents used in industrial battery maintenance, attacks adhesives. Over a ten-year operational life for an industrial battery, or the intended lifecycle of an EV battery pack, an adhesive label applied at the point of manufacture cannot credibly guarantee that the marking will remain visible and legible at end of life.
As a general rule, labels and markings should be visible, legible and indelible, applied to the battery itself. Where a label can be physically separated from the battery, it cannot be indelible in any meaningful sense of the word.
Market surveillance authorities across EU member states are responsible for enforcing this. The regulation gives them powers to require product withdrawal and recall where non-compliance is found. Incorrect or misleading battery labelling can result in product withdrawals, recalls, fines and marketplace delistings. Labelling issues are often treated as a compliance failure even if the battery itself is technically safe.
A label that has peeled away from a battery in a recycling facility is, by definition, a labelling failure.
What Does Pass: Why Laser Marking Satisfies the Requirement
Laser marking works differently from any surface-applied process. A laser beam, in the case of fibre laser marking, a focused beam of infrared light, interacts directly with the surface material of the battery casing. The mark is not applied on top of the surface. It is created within the surface itself, through controlled thermal or photochemical change in the substrate material.
There is nothing to peel. Nothing to lift. Nothing to degrade independently of the battery casing itself.
A laser-marked identifier on an aluminium battery casing will remain on that casing for as long as the casing exists. It will survive the same temperatures, chemicals, vibration and handling that the battery survives. It cannot be separated from the component it identifies without destroying the component itself.
That is what indelible means. And it is precisely what the Battery Regulation demands.
For EV batteries and industrial batteries above 2 kWh, the battery categories facing the most demanding compliance requirements under the regulation, laser marking provides several further practical advantages:
Marking speed. Modern fibre laser systems mark at production line speeds. A data matrix code, serial number, CE mark and carbon footprint classification can all be applied to a battery casing in a single pass, in seconds, without stopping the line.
Data matrix and QR code quality. The QR code must be printed or engraved visibly, legibly and indelibly on the battery. Laser-marked data matrix codes and QR codes achieve the contrast and resolution required for reliable scanning throughout a battery’s lifecycle. A printed or adhesive QR code that has degraded over years of service cannot be reliably read by automated scanning systems in a recycling facility, which defeats the entire purpose of the Battery Passport.
Traceability integration. Every laser-marked identifier can be logged at the point of marking, creating an immediate link between the physical battery and its digital Battery Passport entry. This is the foundation of the traceability chain the regulation is designed to establish.
Material compatibility. Fibre laser marking works on aluminium, steel, nickel-plated surfaces and many of the polymer housings used in battery module construction. MOPA laser systems offer additional control over mark contrast and depth, particularly valuable on anodised aluminium and other surface-treated materials common in battery casing design.
The Packaging Fallback: What It Is and What It Is Not
The regulation does include a provision for situations where marking directly on the battery is not possible or not warranted due to the nature and size of the battery. Article 13(7) of Regulation (EU) 2023/1542 provides that labels must be printed or engraved directly on the battery, unless this is not possible or not justified due to the nature or size of the battery. In such cases, the label must be affixed to the packaging or included in the documentation accompanying the battery.
This fallback is intended for small batteries, button cells, and cylindrical cells below a certain size, where the physical surface area of the battery makes direct marking technically impractical.
Any decision to place part of the required information on the packaging rather than on the battery itself should be justified by physical constraints of the battery surface, taking into account branding and other labelling and marking obligations under Union legislation, while excluding space used solely for non-essential marketing information.
For EV battery packs and industrial batteries above 2 kWh, the physical size argument is not available. These are large components with substantial casing surface area. The packaging fallback does not apply. The marking must be on the battery itself. It must be indelible.
The Commercial Reality
The EU Battery Regulation applies to all batteries placed on the EU market, regardless of where they are manufactured. Regulation (EU) 2023/1542 applies to all new batteries placed on the market or put into service within the European Union from the date the Regulation entered into force, regardless of their origin or place of production.
That means manufacturers in China, South Korea, Japan and the United States supplying batteries to European customers face exactly the same indelible marking requirement as European manufacturers. The competitive advantage goes to the manufacturer who has already solved this problem, who has integrated permanent laser marking into their production process before the deadlines arrive, rather than scrambling to retrofit a solution when market surveillance authorities start checking.
The next few months will bring significant changes to how batteries are labelled and presented, but there is still time to prepare.
The August 2026 labelling deadline is not far away. The February 2027 QR code and Battery Passport deadline follows closely behind.
A Direct Answer to the Direct Question
Indelible, in the context of the EU Battery Regulation, means permanently bonded to the battery surface. It means surviving the full operational lifetime of the battery, including end-of-life processing. It means readable by automated scanning systems years after manufacture. It means that if the marking and the battery can be separated, the marking is not indelible.
Adhesive labels are not indelible. Printed labels are not indelible. Surface coatings that can be abraded or chemically removed are not indelible.
Laser marking is indelible.
We have been building laser marking systems in Sheffield since before the Battery Regulation existed. We know what these applications demand. If you are working through what compliance looks like for your production process, speak to our engineers. We have probably seen your exact challenge before.