As electric vehicles and industrial battery systems scale across Europe, warranty claims are becoming more complex and more costly. High-value lithium-ion batteries are typically covered by performance or capacity warranties that extend for up to eight years. When a claim arises, manufacturers must determine whether the battery failed due to a production defect, misuse, poor maintenance, or operation outside its specified limits.

In this context, immutable usage logs linked to a Digital Battery Passport (DBP) can play a crucial role in verifying or debunking warranty claims. By combining secure data capture with tamper-resistant record-keeping, industry actors can strengthen trust, reduce fraud risk, and improve dispute resolution.

The Regulatory Context: Digital Battery Passports Under EU Law

Regulation (EU) 2023/1542, commonly referred to as the EU Battery Regulation, introduces mandatory Digital Battery Passports for electric vehicle batteries, industrial batteries and light means of transport batteries above 2 kWh from 18 February 2027. The regulation requires lifecycle information, traceability and machine-readable structured data linked to each battery through a unique identifier and accessible via a data carrier on the battery.

Although the regulation focuses on sustainability, transparency, and circularity, the same infrastructure can provide a robust foundation for warranty management by anchoring verified usage data within a trusted digital framework.

The Growing Challenge of Battery Warranty Fraud

Battery warranties often guarantee a minimum State of Health (SOH) or capacity retention over a defined number of years or charge cycles. For electric vehicles, warranties commonly promise a specific percentage of original capacity after eight years or a defined mileage threshold.

However, lithium-ion battery performance is highly sensitive to operational conditions. Excessive fast charging, repeated deep discharge, extreme temperatures or unauthorised modifications can accelerate degradation. When a battery fails prematurely, distinguishing between manufacturing defects and operational stress is not always straightforward.

Given the high cost of battery replacement, even a relatively small proportion of disputed or fraudulent claims can have significant financial consequences for manufacturers and fleet operators. As the installed base of EVs and industrial batteries grows, the scale of potential warranty exposure increases accordingly.

How Immutable Usage Logs Can Help

An immutable usage log is a structured record of operational data that cannot be altered retroactively without detection. Such logs can include:

• Charge and discharge cycles
• Depth of discharge patterns
• Temperature exposure
• Fast charging frequency
• Alerts, fault codes and safety events

However, conventional logging does not guarantee such in-depth information. Battery Management Systems (BMS) already capture much of this data for performance optimisation and safety. The key challenge is ensuring that these logs are securely preserved and linked to the battery’s digital identity.

Immutability is typically achieved through cryptographic techniques such as digital signatures and hash functions. A cryptographic hash produces a unique fingerprint of a dataset. If the dataset changes, the hash also changes, immediately signalling tampering. This principle is widely used in digital security and data integrity verification.

Digital signatures provide an additional layer of security by allowing verifiers to confirm that data originated from a specific trusted source and has not been altered since signing.

The European Union Agency for Cybersecurity explains how digital signatures support integrity, authenticity and non-repudiation in digital transactions.

With these mechanisms integrated into the battery usage logs, manufacturers and authorised service providers can maintain a trustworthy operational history.

Verifying Warranty Claims With Trusted Data

When a warranty claim is submitted, access to secure usage logs helps manufacturers to conduct objective analysis. If logs show that the battery consistently operated within specified voltage, temperature and charging parameters, a manufacturer may confirm a legitimate defect and honour the claim.

If, however, the data indicates repeated operation outside warranty conditions, such as sustained over-temperature events or unauthorised software modification, the claim can be evaluated in light of documented evidence.

This approach reduces reliance on subjective reporting and manual investigation. It also supports fair treatment of customers by basing decisions on verifiable data rather than assumptions.

Importantly, transparent and secure logging strengthens legal defensibility. In disputes, cryptographically protected records provide stronger evidentiary value than editable local files or informal service notes.

Aligning Warranty Data With Regulatory DBP Architecture

The EU Battery Regulation emphasises lifecycle data, traceability and interoperability across the value chain. The Digital Battery Passport must contain structured information and be accessible through a machine-readable data carrier.

While warranty data is not the central focus of the regulation, integrating immutable usage logs into the broader passport framework aligns closely with its objectives. A secure digital identity linked to lifecycle records supports:

• Clear attribution of responsibility
• Transparent performance history
• Efficient information sharing between authorised actors

In practice, this means that warranty-relevant usage data can be referenced within the passport architecture, subject to appropriate access controls and data protection safeguards.

Data Governance And Privacy Considerations

Immutable logging must be balanced with data protection obligations. Usage logs may contain information linked to specific vehicles, operators or usage patterns. Under the General Data Protection Regulation (GDPR), personal data must be processed lawfully, transparently and for specified purposes.

Therefore, warranty-related logging systems must define:

• Clear data ownership and access rights
• Role-based permissions
• Retention periods aligned with warranty duration
• Secure storage and encryption

Combining cryptographic integrity with responsible governance will ensure that fraud prevention measures do not compromise privacy or regulatory compliance.

How BASE Strengthens Warranty Integrity Through Digital Battery Passports

At BASE, we recognise that warranty assurance is an important operational dimension of the Digital Battery Passport ecosystem. Our Digital Battery Passport framework is designed to support structured lifecycle data, secure identity management and cryptographic integrity mechanisms that align with best practices in digital security.

By enabling authenticated data capture and secure linkage between battery identity and usage records, BASE can help manufacturers and authorised stakeholders build trusted evidence chains. Our approach supports role-based access control so that warranty evaluators can review relevant data without exposing unnecessary sensitive information.

Through interoperable and standard-aligned architectures, BASE contributes to a more transparent and reliable battery value chain where warranty claims can be assessed using verifiable evidence rather than fragmented records.

Building Trust In The Battery Value Chain

As battery systems grow in value and complexity, warranty management will remain a strategic concern for manufacturers, fleet operators and energy storage providers. Immutable usage logs anchored in a Digital Battery Passport can provide a practical and secure method for preventing warranty fraud while protecting legitimate customer claims.

By combining cryptographic integrity, structured lifecycle data and clear governance policies, the industry can reduce disputes, improve accountability and strengthen confidence in battery performance guarantees.

For organisations preparing for the 2027 Digital Battery Passport requirements, integrating secure usage logging into passport architectures is a forward-looking step that supports both compliance and commercial resilience.

The BASE project has received funding from the Horizon Europe Framework Programme (HORIZON) Research and Innovation Actions under grant agreement No. 101157200.

References

Regulation (EU) 2023/1542 – EU Battery Regulation: https://eur-lex.europa.eu/eli/reg/2023/1542/oj

Regulation (EU) 2023/1542 consolidated version:  https://eur-lex.europa.eu/eli/reg/2023/1542/2023-07-28/eng

NIST Glossary – Hash Function: https://csrc.nist.gov/glossary/term/hash_function

European Union Agency for Cybersecurity – Digital Identity and Data Protection: https://www.enisa.europa.eu/topics/digital-identity-and-data-protection

Regulation (EU) No 910/2014 – eIDAS Regulation: https://eur-lex.europa.eu/eli/reg/2014/910/oj

Regulation (EU) 2016/679 – General Data Protection Regulation: https://eur-lex.europa.eu/eli/reg/2016/679/oj