The issue is becoming urgent as electric vehicles become more common and their battery systems grow larger and more technically complex. A modern traction battery must manage electrical output, heat, mechanical forces and crash loads at the same time. These demands are frequently addressed through highly integrated designs in which cells, cooling systems, adhesives, structural components and electronic controls are combined into a single package. While such integration can reduce manufacturing complexity and improve performance, it can also make the battery extremely difficult to disassemble. For emergency responders, inconsistent pack designs create an additional hazard because the location of high-voltage components, damaged cells and cooling circuits can differ substantially from one vehicle to another.

“Without uniform design standards, emergency services often face major challenges in an emergency because the structure and behaviour of battery systems are difficult to assess,” says Markus Fasching of the Vehicle Safety Institute at Graz University of Technology, the project’s manager. A battery that has been involved in a collision may appear inactive while still containing dangerous electrical energy. Internal damage can also trigger chemical and thermal reactions hours after the original impact. If responders cannot quickly determine how the pack is constructed or whether individual cells are compromised, extinguishing, transporting and storing the vehicle becomes more difficult. The same lack of transparency affects recycling companies, which must handle battery packs with widely differing structures and disassembly procedures.

The researchers used a commonly deployed battery construction as a reference design: a bonded housing combined with thermally conductive pastes used to transfer heat away from the cells. This approach can be effective during production and operation, helping maintain a stable temperature across the pack. However, adhesives and thermally conductive compounds can make it difficult to separate components without damaging them. In many cases, a defect in a limited number of cells may therefore result in the replacement of the entire battery pack. Such a system can be reliable during normal use, yet economically and environmentally inefficient after an accident or localized failure.

The E-Track team compared this baseline with alternative designs intended to make disassembly more practical. One concept used replaceable housing covers and heat-dissipation pads rather than permanently bonded structures. Another employed liquid cooling, with an electrically insulating oil transferring heat away from the cells. In that design, the housing could be opened by removing screws, while a seal helped prevent leakage. The purpose was not simply to make the pack easier to open, but to create a pathway for technicians to identify and replace individual damaged cells. A modular approach of this kind could reduce the amount of material discarded after a crash and allow healthy components to remain in service.

The environmental calculations point to a surprisingly low threshold for repairability. Battery cells account for approximately 75 percent of the total mass of the systems examined, making them the dominant factor in the pack’s material footprint. Life-cycle analyses conducted by the researchers indicate that repair-friendly construction becomes worthwhile when just eight percent of the cells can be reused. In other words, a battery does not need to be almost entirely recoverable to gain an environmental advantage. Saving a relatively small fraction of its cells can already offset some of the impacts associated with manufacturing replacement cells and processing a complete pack for recycling.

This finding is important because battery cells embody much of the energy, raw material extraction and industrial processing associated with an electric vehicle. Reusing a functioning cell can preserve the value of materials such as lithium, nickel, cobalt, manganese, copper and aluminium, depending on the chemistry and design of the battery. Recycling remains essential for cells that cannot safely be reused, but direct reuse can retain more of the original product’s value. It may also reduce demand for new cell production, which is one of the most energy-intensive stages in the battery life cycle. The researchers therefore argue that repairability should be treated as a central design objective rather than an afterthought.

Opening a battery safely is only part of the challenge. Technicians must also determine whether a cell has suffered hidden damage that could later produce a short circuit, overheating or thermal runaway. The E-Track researchers developed diagnostic approaches based on electrochemical impedance spectroscopy, a technique that measures how a battery responds to electrical signals across different frequencies. Changes in the measured impedance can reveal alterations in internal resistance, charge-transfer processes and other electrochemical properties. These signals may help distinguish healthy cells from those affected by mechanical impact or internal defects that are not visible from the outside.

The diagnostic measurements were combined with virtual multiphysical models that simulate interactions between electrical, thermal and mechanical behaviour. Such models can help researchers understand how a small internal defect might evolve under different conditions, including charging, discharging, vibration or elevated temperature. Of particular concern are micro-shorts, in which damaged internal layers create a tiny electrical connection inside a cell. A micro-short may initially generate little heat and remain undetected, but it can become a delayed source of thermal instability. Identifying these risks before a battery is returned to service could prevent fires and improve confidence in second-life applications.

Although the project focused primarily on electric two-wheelers, the researchers say that its methods can be transferred to larger battery systems used in passenger cars, commercial vehicles and lorries. The work provides a potential foundation for future industrial standards covering pack architecture, emergency access, diagnostic testing and end-of-life treatment. Standardization could give firefighters and recovery teams more predictable information while helping manufacturers design batteries that can be opened, repaired and recycled with less specialized effort. Industry partners have already expressed interest in follow-up research focused on safety diagnostics and multiphysical simulation. Funded by the Austrian Research Promotion Agency, the E-Track project delivers a message that could reshape battery engineering: the most sustainable battery may not be the one that lasts forever, but the one designed to be understood, repaired and used again.

Subject of Research: Not applicable

Article Title: Design matters: The influence of EV battery pack design for disassembly on environmental and circularity impact

News Publication Date: 1-Jun-2026

Web References: https://doi.org/10.1016/j.spc.2026.04.003

References: Sustainable Production and Consumption, “Design matters: The influence of EV battery pack design for disassembly on environmental and circularity impact,” DOI: 10.1016/j.spc.2026.04.003

Keywords

electric vehicles, EV batteries, battery recycling, battery repair, circular economy, battery safety, thermal runaway, electrochemical impedance spectroscopy, sustainable design, disassembly, electric mobility, lithium-ion batteries

The global surge in energy demand, driven by rapid advancements toward renewable energy systems and electric vehicles, underscores the importance of efficient energy storage solutions. Batteries, laden with critical metals such as copper, cobalt, lithium, and manganese, are central to this transformation. However, these metals are finite and largely sourced outside Europe, posing supply risks exacerbated by geopolitical tensions and market concentration. The European Union’s Critical Raw Materials Act highlights the precarious nature of such dependencies, emphasizing the urgent need for sustainable recycling techniques capable of ensuring a stable supply chain while mitigating environmental and safety impacts.

Battery production demands metals of exceptional purity, particularly for cutting-edge applications. Recycling processes must therefore not only extract metals but also achieve a degree of separation and refinement that prevents contamination with hazardous substances. Historically, impurities like mercury were tolerated or even intentionally added—for instance, mercury extended the shelf life of zinc electrodes in disposable batteries. Today, higher purity requirements have enabled manufacturers to eliminate such toxic additives, enhancing both product safety and environmental outcomes. The degradation of metal quality through substandard recycling threatens this balance, underscoring the need for advanced purification methods.

Metal recycling industrial procedures often employ solvent extraction, a sophisticated technique involving the transfer of metals from aqueous phases into organic solvents. This method relies on extractants—molecules that bind selectively to target metals—and diluents, which dissolve these extractants to create functional organic phases. Conventional diluents are predominantly derived from petroleum feedstocks, raising concerns about sustainability, human safety, and environmental toxicity. The Chalmers team focused on substituting these with aromatic compounds sourced from renewable biomass, such as forestry by-products, thereby cutting reliance on fossil resources without disrupting existing manufacturing infrastructure.

The research specifically examined two biomass-derived aromatic diluents, assessing their efficacy in the selective extraction of key metals from spent batteries. These compounds demonstrated extraction performance on par with, and in some cases surpassing, that of well-established commercial solvents. Crucially, the new diluents could be seamlessly integrated into current industrial solvent extraction processes, thus eliminating costly retrofits or plant modifications that frequently obstruct the adoption of greener technologies in heavy industry. This pragmatic compatibility could accelerate the transition to safer, sustainable chemical use in metal recovery.

Beyond their extraction capacity, the novel aromatic diluents possess significantly higher flash points and reduced volatility compared to traditional solvents. This dual advantage lowers the risk of combustion hazards and minimizes worker exposure to toxic emissions, addressing major industrial safety concerns. Many established solvents degrade into neurotoxic by-products with detrimental effects on human and animal nervous systems. By contrast, the Chalmers compounds are designed to avoid such degradative pathways, representing a substantial step forward in occupational and environmental health standards.

Mark Foreman, Associate Professor at Chalmers and co-author of the study, emphasizes that maintaining the quality of recycled metals is not solely an economic imperative but a safeguard for the entire lifecycle of recycled materials. Without rigorous purification, recycled metals risk becoming too contaminated for use in advanced applications, effectively negating the ecological benefits of recycling. This research thus sets a new benchmark for sustainable chemistry practices in the circular economy, promising to uphold both metal integrity and environmental stewardship.

Daniel Keywan Hoffmann, a PhD student and lead researcher, points out that the successful demonstration of renewable diluents highlights an underestimated route to greener industrial chemistry: substituting existing chemicals rather than complete process reinvention. The compatibility of these bio-based solvents with current solvent extraction units suggests industries can enhance sustainability affordably by swapping hazardous materials for safer alternatives, bypassing expensive capital investments and extensive downtime.

Implementing renewable aromatic diluents on a commercial scale will require further optimization of manufacturing methods and an upscaling of biomass feedstock availability. However, this challenge aligns with broader trends in the forestry and bioproduct sectors, which increasingly valorize waste streams as raw materials for high-tech chemical production. Leveraging these synergies could foster a circular bioeconomy, linking battery recycling with sustainable forestry management and green chemical manufacturing.

The implications for environmental safety are profound. The shift to renewable diluents reduces the ecological footprint of metal recovery by decreasing emissions of volatile organic compounds and eliminating neurotoxic degradation products. In addition, safer handling conditions lower health risks for workers in facilities engaged in large-scale solvent extraction processes. Such improvements contribute to the United Nations Sustainable Development Goals by fostering safer industrial environments and promoting resource efficiency.

This academic advance comes at a pivotal moment as nations worldwide ramp up electric battery production to meet decarbonization targets. Europe, in particular, is striving to obtain greater autonomy over critical materials supply chains, with recycling poised as a cornerstone strategy. Innovations like those from Chalmers University could thus play a decisive role in closing material loops, reducing dependence on imports, and elevating the sustainability profile of battery technologies critical to the green economy.

In summary, the Chalmers research offers a compelling blueprint for greener, safer, and economically feasible metal recycling processes. By harnessing biomass-derived aromatic compounds as solvent extraction diluents, the study illustrates a path to enhance the purity of recycled metals while mitigating environmental and health hazards. It exemplifies how incremental yet strategic chemical substitutions can catalyze significant sustainability gains in industrial operations, charting a course toward a more resilient and responsible materials economy.

Subject of Research: Not applicable

Article Title: Safer aromatic process diluents for solvent extraction of critical metals from spent batteries

News Publication Date: Not explicitly provided; article publication date is 7-May-2026

Web References:

• Study DOI: 10.1039/D6SU00096G
• EU Critical Raw Materials Act infographic: https://www.consilium.europa.eu/en/infographics/critical-raw-materials/

References:

• Hoffmann, D.K. et al. “Safer aromatic process diluents for solvent extraction of critical metals from spent batteries,” RSC Sustainability, 7-May-2026, DOI: 10.1039/D6SU00096G.

Image Credits: Chalmers University of Technology

Keywords

Battery recycling, solvent extraction, renewable biomass, aromatic diluents, metal recovery, critical raw materials, sustainability, green chemistry, solvent toxicity, circular economy, cobalt recycling, lithium recovery