As the 18 February 2027 deadline for mandatory Digital Battery Passports approaches, battery manufacturers and other economic operators are preparing to collect, structure and share increasingly complex datasets.
However, having the required information is only part of the challenge. Organisations also need to demonstrate where the data came from, how it was generated, who changed it and whether it has remained reliable.
This is where audit trails and evidence management become essential.
Under Regulation (EU) 2023/1542, the economic operator placing a battery on the EU market must ensure that Battery Passport information is accurate, complete and up to date. The regulation also requires data authentication, reliability and integrity, with access to introduce, modify and update information appropriately restricted.
The question for organisations is therefore not simply whether the right data exists, but whether they can prove and trace it.
Previously we’ve discussed Making Battery Passports Audit-Ready: What Market Surveillance Authorities Will Check and how importers should prepare for Battery Passport Customs check. Today we’ll look into Battery Passport Audit Trails and Evidence Management for proving data provenance and integrity.
What Is A Battery Passport Audit Trail?
An audit trail is a chronological record showing how information has been created, changed, reviewed or updated.
For a Battery Passport, this could mean tracing a data field through a chain such as:
Battery Passport data → source system → original record → supporting evidence → responsible person or organisation
Consider a battery's State of Health value. The Passport may contain the current value, but an audit-ready system should also make it possible to determine how that value was measured or calculated, when it was recorded and how it changed over time.
The same principle applies to information such as performance, durability, carbon footprint, recycled content and manufacturing data.
An audit trail provides the history and context behind the information presented in the Battery Passport.
Proving Data Provenance
Data provenance refers to the origin and history of information.
Battery data can originate from many sources. Manufacturing systems may provide production information, laboratories may generate test results, Battery Management Systems may produce operational data, and suppliers may provide information about materials and components.
A reliable Battery Passport implementation should make it possible to identify the source of important information and understand how it entered the Passport.
This becomes particularly important when data is collected from multiple organisations across the battery value chain.
The Batteries Regulation requires the Battery Passport to contain information relating to the battery model as well as individual batteries, including information resulting from their use. It also identifies test report results demonstrating compliance as information that must be accessible to relevant authorities and notified bodies.
Maintaining clear provenance therefore helps organisations demonstrate the basis for information contained in the Passport.
Protecting Data Integrity
Provenance shows where data came from. Data integrity addresses whether that information has remained accurate and protected from unauthorised modification.
Article 78 of the Batteries Regulation requires Battery Passport data to provide authentication, reliability and integrity, while also requiring appropriate controls over who can introduce, modify or update information.
In practice, organisations should be able to answer questions such as:
- Who created or changed the information?
- When was the change made?
- What was changed?
- What was the previous value?
- Was the person or system authorised to make the change?
This is particularly important for Battery Passport data that may be updated throughout a battery's lifecycle.
A reliable audit trail should preserve the history of significant changes rather than simply replacing the previous value with a new one.
What Evidence Supports Battery Passport Data?
Different Battery Passport attributes may require different types of supporting evidence.
Depending on the data and applicable requirement, evidence may include:
- Test and measurement results
- Manufacturing records
- Inspection records
- Calibration records
- Technical calculations
- Supplier documentation
- Certification or verification records
- Performance and durability data
- Operational records generated during battery use
The Batteries Regulation specifically identifies test report results demonstrating compliance among the information that must be accessible to notified bodies, market surveillance authorities and the European Commission.
Organisations should therefore consider the relationship between a data attribute and the evidence supporting it.
Instead of simply storing a final value, a robust system should make it possible to trace that value back to its underlying evidence.
Building A Chain Of Evidence
A practical evidence model can be represented as:
Data Attribute → Source → Measurement or Calculation → Evidence → Validation → Battery Passport
For example, if a manufacturer reports a particular performance value, it should be possible to identify the source data, the methodology or calculation used, the relevant measurement or test record and, where applicable, the person or system responsible for validating the result.
This creates a stronger basis for verification than simply storing the final result.
It also makes it easier to identify which Passport information may need to be reviewed when an underlying source, calculation or test result changes.
Why Version History Matters
Battery Passport information can change throughout a battery's lifecycle.
Information may be updated as a battery is used, repaired, repurposed, remanufactured or reaches end-of-life. The regulation requires relevant information to remain accurate, complete and up to date.
This means organisations need to distinguish between updating information and losing its history.
Version control can preserve information about what was recorded at different points in time. For significant changes, an audit trail should ideally show:
what changed → when it changed → who or what changed it → why it changed
This provides a clearer record of the data's history and can support investigations, verification and regulatory checks.
From Data Management To Audit Readiness
A practical way to assess Battery Passport audit readiness is to select a representative battery and work backwards from one of its Passport fields.
Ask:
Where did this information come from?
Can you identify the original source? Can you find the underlying record? Can you identify the calculation, measurement or methodology behind it? Can you locate the supporting evidence? Can you establish when the information was created or changed? Can you demonstrate that the relevant changes were made by authorised users or systems?
If these questions can be answered quickly and consistently, the organisation has a much stronger foundation for demonstrating data provenance and integrity.
If the answers depend on searching through emails, spreadsheets and disconnected document repositories, the organisation may need to strengthen its evidence and data governance processes before the 2027 deadline.
How BASE Can Help
The BASE project is working towards trusted and interoperable Digital Battery Passport solutions that support reliable information exchange throughout the battery value chain.
Auditability is an important part of this objective. Battery Passport data needs to be more than accessible. It needs to be structured, traceable and capable of maintaining its integrity as information moves between systems and organisations.
BASE's work on Battery Passport data attributes and standards contributes to this foundation by supporting consistent approaches to structuring and exchanging Battery Passport information.
Making Battery Passport Data Audit-Ready
The value of an audit trail becomes clear when an auditor, regulator or business partner asks a simple question:
"How do you know this information is correct?"
A reliable Battery Passport implementation should make it possible to answer that question with evidence.
By connecting data attributes to their sources, maintaining relevant version histories and preserving supporting evidence, organisations can build a stronger basis for proving data provenance, accuracy and integrity.
As the Battery Passport becomes part of the European battery ecosystem, organisations that build auditability into their data processes from the beginning will be better prepared to demonstrate the reliability of their information throughout the battery lifecycle.
The BASE project has received funding from the Horizon Europe Framework Programme (HORIZON) Research and Innovation Actions under grant agreement No. 101157200.
References & Resources
Regulation (EU) 2023/1542 - Batteries and Waste Batteries Regulation: https://eur-lex.europa.eu/eli/reg/2023/1542/oj
European Commission - Digital Product Passport for Batteries (Battery Passport): https://single-market-economy.ec.europa.eu/single-market/digital-product-passport/batteries_en
European Commission - The DPP Registry: https://single-market-economy.ec.europa.eu/single-market/digital-product-passport/dpp-registry_en
European Commission - The Digital Product Passport Registry Is Now Live: https://single-market-economy.ec.europa.eu/news/digital-product-passport-registry-now-live-2026-07-20_en
BASE Project - Making Battery Passports Audit-Ready: What Market Surveillance Authorities Will Check: https://base-batterypassport.com/blog/regulations-4/how-market-surveillance-authorities-check-battery-passports-129