As Europe moves towards a more transparent and circular battery economy, the Digital Battery Passport (DBP) is emerging as a critical tool for compliance, traceability and lifecycle management. Introduced under Regulation (EU) 2023/1542, the DBP will become mandatory for batteries above 2 kWh placed on the European market from February 2027. It requires structured, machine-readable data on battery composition, performance, carbon footprint and lifecycle events.

While the conversation often centres on electric vehicles, some of the most demanding and revealing applications lie in maritime transport and emerging electric aviation systems. High-capacity ferry batteries and electric vertical take-off and landing aircraft, commonly known as eVTOL, present operational environments that test the limits of how Digital Battery Passports should be designed and implemented.

Scaling the Digital Battery Passport for High-Capacity Maritime Systems

Battery systems used in maritime applications operate at a fundamentally different scale compared to automotive systems. Electric ferries can carry battery systems measured in megawatt-hours, composed of thousands of individual cells arranged into modules, packs and integrated system architectures.

For example, large electric ferries deployed in Nordic regions rely on modular battery systems that are serviced and upgraded over long operational lifetimes. These systems are rarely static. Modules may be replaced, reconfigured or repurposed as performance requirements evolve.

This raises a fundamental challenge for Digital Battery Passports. If traceability is required at a detailed level, should each cell, module or pack have its own passport? Creating thousands of individual passports for a single vessel would quickly become unmanageable. On the other hand, maintaining a single, static passport at the vessel level would obscure critical technical details.

A more practical approach lies in layered data structures. In this model, a system-level passport is linked to module-level and component-level identifiers through structured relationships. This allows traceability to be maintained without overwhelming users with excessive data fragmentation. It also supports lifecycle updates when modules are replaced or reconfigured, ensuring that the passport reflects the current state of the system.

Connectivity and Data Synchronisation at Sea

Maritime operations introduce another layer of complexity. Vessels often operate in environments with limited or intermittent connectivity. Satellite communication may be available, but bandwidth constraints and cybersecurity considerations mean that continuous data exchange is neither practical nor desirable for critical systems.

This has direct implications for the Digital Battery Passport. Lifecycle events such as maintenance, module replacement or performance updates may occur while the vessel is offline. These changes must still be recorded in a secure and verifiable way.

A viable approach is to support local data recording combined with controlled synchronisation. Updates can be stored securely onboard and then synchronised with external systems during port calls or scheduled maintenance intervals. This ensures that data remains accurate and tamper-resistant while respecting operational autonomy.

Such an approach aligns with the broader requirements of the EU Battery Regulation, which emphasises traceability, data integrity and accessibility without prescribing continuous connectivity.

Aviation Batteries: Aligning Digital Passports with Certification Requirements

In aviation - particularly for emerging eVTOL platforms and hybrid-electric aircraft - battery systems face a different but equally demanding challenge. These systems must deliver very high energy density while complying with some of the strictest safety certification regimes in any industry.

Like maritime batteries, aviation battery systems are modular. They are built from large numbers of individual cells organised into modules and packs, integrated into propulsion and auxiliary systems. However, unlike most maritime applications, aviation systems operate under airworthiness certification frameworks that require rigorous validation of every safety-critical component.

Battery systems in aircraft must demonstrate controlled failure behaviour, thermal containment, fault isolation, and redundancy. In the aviation industry, configuration management is mandatory: any change in module composition, software version, or operating envelope must be formally documented, verified, and approved within the certification framework.

This is where the Digital Battery Passport intersects with aviation governance. In this context, the DBP cannot function merely as a sustainability reporting tool. Lifecycle transparency is directly linked to configuration tracking, maintenance records, and compliance evidence. If modules are replaced, software is updated, or performance limits are adjusted, these changes must remain traceable and aligned with certified configurations.

Connectivity also differs from common assumptions. Aircraft are not permanently connected systems, and safety-critical components are not dependent on live cloud communication. Data may be recorded onboard and synchronised during maintenance intervals or controlled ground operations. The DBP architecture must therefore accommodate secure, authenticated update mechanisms rather than rely on continuous remote data exchange.

In aviation, battery data integrity is directly embedded in formal airworthiness certification frameworks. This means that transparency must align with certification logic. This requires careful coordination between regulatory requirements under the Battery Regulation and aviation authorities’ airworthiness frameworks. Therefore, in the aviation environment, the DBP becomes part of a structured chain of technical accountability, supporting traceability without compromising operational autonomy or certification discipline.

Designing for Modularity, Traceability and Interoperability

Both maritime and aviation applications highlight the need for a more flexible and scalable Digital Battery Passport architecture. Several key principles emerge from these use cases.

First, modularity is essential. Batteries are not static products but evolving systems. The passport must reflect this by supporting hierarchical relationships between cells, modules and system-level configurations.

Second, traceability must remain consistent across these layers. Unique identifiers should link components across the lifecycle, enabling stakeholders to track changes, replacements and performance history without losing context.

Third, interoperability is critical. The EU Battery Regulation requires that passport data be machine-readable and accessible across stakeholders. This means that data models must be standardised and capable of supporting complex system structures across different industries.

Finally, data governance must balance transparency with security. Sensitive operational data must be protected, while still allowing authorised access for compliance, maintenance and lifecycle decision-making.

Real-World Implications for Industry

These challenges are not theoretical. They are already shaping how organisations approach battery system design and lifecycle management.

In maritime systems, operators must ensure that long-lived battery assets can be tracked and maintained over decades, often across multiple ownership or operational contexts.

In aviation, manufacturers and operators must integrate battery data into certification processes, ensuring that every lifecycle event is documented and verifiable.

Across both sectors, the Digital Battery Passport becomes more than a compliance requirement. It evolves into a core part of operational infrastructure, supporting maintenance planning, safety assurance and circular economy strategies.

The International Energy Agency highlights that digitalisation and data transparency are essential for scaling battery deployment and improving lifecycle performance across sectors.

How BASE Supports Complex Digital Battery Passport Architectures

At BASE, we recognise that high-capacity and safety-critical applications require more than a one-size-fits-all approach to Digital Battery Passports. Our framework is designed to support modular, interoperable and scalable data architectures that align with the realities of maritime and aviation systems.

The BASE Digital Battery Passport enables structured relationships between system, module and component-level data, allowing lifecycle updates to be captured without losing traceability. It also supports secure data exchange and role-based access, ensuring that sensitive operational information remains protected while still accessible to authorised stakeholders.

By incorporating flexible data models and supporting offline-to-online synchronisation workflows, BASE helps ensure that passport data remains accurate and reliable even in environments with limited connectivity. Through collaboration and pilot activities, we are exploring how these approaches can be applied in complex industrial systems, contributing to a more resilient and interoperable battery ecosystem.

Closing Thoughts

Safety and data integrity matter in every battery application - whether in cars, ships, or aircraft. What differs is how these elements are governed in and by those industries. In automotive systems, safety is ensured through type approval and standardised production controls. In maritime systems, safety is overseen through classification and long-term operational management. In aviation, safety is embedded in highly structured certification and configuration control regimes.

These differences matter for the Digital Battery Passport and how it can be or should be tailored:

• In automotive systems, the main challenge is the scale of deployment and supply chain complexity. Millions of batteries are produced across global platforms, often shared between vehicle models and markets. The Digital Battery Passport must therefore ensure consistent data across large production volumes, support ownership changes over time, and enable traceability from manufacturing to second-life and recycling
• In high-capacity maritime systems, the key question is scale and modularity: how to manage thousands of cells within one vessel without creating thousands of separate passports
• In aviation, the challenge lies in aligning lifecycle data with strict certification and configuration control requirements

In complex industrial systems, the DBP becomes part of operational architecture - connected to maintenance, configuration management, and structured accountability over time. 

If the Digital Battery Passport is to function as a durable instrument for transparency and circularity, it must adapt to these sector-specific realities. Maritime and aviation applications do not represent edge cases; rather, they reveal how robust - and how flexible - the DBP framework will need to be in practice.

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

EU Battery Regulation Detailed Text

https://eur-lex.europa.eu/eli/reg/2023/1542/2023-07-28/eng

International Energy Agency – Global EV Outlook 2023

https://www.iea.org/reports/global-ev-outlook-2023

International Energy Agency – EU Sustainable Batteries Regulation: https://www.iea.org/policies/16763-eu-sustainable-batteries-regulation