Battery recycling is often discussed in terms of circular economy targets, material recovery rates, and critical raw materials. But before metals are recovered or sustainability targets are met, a more immediate question arises:

"What risks are present when a battery first arrives at a recycling facility?"

End-of-life does not mean risk-free. Even batteries classified as damaged, aged, or decommissioned may still contain residual voltage, unstable cells, degraded electrolytes, or internal defects. When faulty batteries are opened, dismantled, or transported, uncertainty becomes a direct operational hazard.

Worker safety in recycling is therefore not only about protective equipment or procedures. Increasingly, it is about access to reliable information before physical handling.

The Hidden Risks Inside End-of-Life Batteries

Lithium-based batteries can retain significant electrical charge even after their useful life in vehicles or stationary applications. If residual voltage is not properly identified, unintended short circuits, sparks, or thermal events may occur during disassembly.

In addition to electrical risk, chemical exposure remains a concern. Lithium-ion batteries contain flammable electrolytes and reactive materials that, if released due to mechanical damage or internal failure, may emit irritant or potentially toxic vapours. Damaged cells may release electrolyte gases, while compromised modules may expose workers to substances that can cause respiratory irritation, skin contact hazards, or localised contamination of dismantling environments. In many cases, such risks are not immediately visible from the exterior of the battery pack.

From the outside, many of these conditions are not visible.

Without structured lifecycle information, recyclers often rely on external inspection, experience, and precautionary protocols. While these remain essential, uncertainty increases operational complexity and risk.

The EU Battery Regulation and the Role of Digital Transparency

Regulation (EU) 2023/1542, coming into force in February 2027, introduces new requirements for lifecycle transparency through the Digital Battery Passport (DBP). While the regulation is widely associated with sustainability, carbon footprint reporting, and circularity targets, it also has implications for safety and traceability.

The DBP framework is intended to provide structured, interoperable access to battery-related information across the value chain. This includes technical data points relevant to composition, performance, and lifecycle history.

In practice, this means that information such as battery chemistry, configuration and module structure, state-of-health (SoH), state-of-charge (SoC), safety-related indicators, and usage and degradation data can be digitally linked to the battery throughout its lifecycle. For recyclers, such transparency is not merely administrative. It has the potential to reduce uncertainty before a battery is physically handled.

Safety Indicators and SoX: From Measurement to Prevention

Within technical discussions, safety-related battery indicators are often grouped under broader State-of-X (SoX) methodologies. These include:

• State-of-Health (SoH)
• State-of-Charge (SoC)
• State-of-Safety (SoS)
• Remaining Useful Life (RUL)

When systematically calculated and documented, such indicators provide a more structured understanding of battery condition.

Residual voltage, reflected in SoC values, can signal immediate electrical handling risks. At the same time, degradation trends and safety flags derived from Battery Management System (BMS) data may indicate previous abnormal events, overheating incidents, or structural instability - all of which can correlate with increased likelihood of electrolyte leakage or chemical instability.

While residual voltage represents a direct electrical hazard, chemical risk may be less visible but equally significant. Structured lifecycle data - including chemistry type, incident history, thermal events, and degradation patterns - can help anticipate potential chemical irritants or instability before physical dismantling begins.

If such data is accessible through a Digital Battery Passport before handling, it can support risk assessment procedures, segregation strategies, and handling protocols.

Bridging Lifecycle Data and End-of-Life Operations

Projects exploring the Digital Battery Passport framework are testing how technical indicators, lifecycle data, and structured reporting can be integrated into interoperable digital systems.

The objective is not to claim that all recyclers will instantly operate with perfect digital transparency. Rather, it is to examine how regulatory requirements and technical architectures can be aligned in a way that makes structured battery data accessible at critical transition points - including end-of-life. When lifecycle information follows the battery, worker safety becomes part of the broader digital transition.

How the BASE Project Contributes to Safer Battery Lifecycle Data

Within this evolving regulatory and technological landscape, the BASE project is exploring how Digital Battery Passport systems can support structured and interoperable battery data management.

BASE focuses on developing a trusted Digital Battery Passport framework that can connect lifecycle information with stakeholders across the battery value chain. By improving data interoperability and traceability, the project aims to ensure that relevant technical information can be accessed when it is needed.

For recycling operators, this type of digital infrastructure could provide earlier insight into battery condition and potential hazards before dismantling begins. By strengthening the flow of reliable data across the battery lifecycle, BASE contributes to a more transparent ecosystem in which safety, sustainability and regulatory compliance reinforce each other.

Safety as a Foundation for Circularity

Circular economy ambitions depend on safe dismantling, transport, reuse, and recycling. Without safe working conditions, circularity targets cannot be achieved responsibly.

The EU Battery Regulation places strong emphasis on due diligence, traceability, and sustainability performance. These elements are interconnected. Transparent data flows not only support compliance and reporting, but they also reduce informational blind spots in operational environments.

Identifying residual voltages and potential chemical irritants before a human touches a battery is not simply a technical improvement. It represents a shift toward a more informed, structured, and preventative approach to battery lifecycle management.

As Digital Battery Passport frameworks mature, digital transparency may become an essential layer of worker protection, reinforcing both regulatory objectives and operational safety in the evolving battery value chain.

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: https://eur-lex.europa.eu/eli/reg/2023/1542/oj

International Energy Agency – Global EV and battery market analysis: https://www.iea.org/reports/global-ev-outlook-2024

European Agency for Safety and Health at Work – Hazardous substances and workplace risk: https://osha.europa.eu/en/themes/dangerous-substances

Sustainable Products Initiative: https://ec.europa.eu/info/law/better-regulation/have-your-say/initiatives/12567-Sustainable-products-initiative_en

ScienceDirect - State-of-X estimation for lithium-ion batteries in electric vehicles: https://www.sciencedirect.com/science/article/abs/pii/S2352152X26006407