Roughly half of the lithium-ion batteries collected from power tools still carry a meaningful charge when they reach recycling facilities. Yet turning these batteries into a second life remains economically unviable at scale. The EASLi project, coordinated by Stiftung GRS and backed by the German Federal Environmental Foundation (DBU), set out to map which recovery pathways work for different spent batteries—and discovered that smarter sorting earlier in the chain is essential.

The consortium brought together Robert Bosch Power Tools, Gemeinsame Rücknahmesystem Servicegesellschaft mbH, Battery Damage Service (BDS), Erlos Produktion und Montagen GmbH, and ECOLOGICON GmbH to examine nickel manganese cobalt (NMC) lithium-ion batteries from power tools. Running from January 2025 through February 2026, the research evaluated three recovery routes: refurbishing for continued use (Loop 1); high-value hydrometallurgical recycling to feed cathode production (Loop 2); and pyrometallurgical processing for lower-grade materials (Loop 3).

What the collection stream actually contains

Three sorting campaigns processed over four metric tons of batteries from take-back sites, recycling centers, and home improvement stores. Lithium-ion batteries represented roughly 55% of the power tool batteries examined. Nickel-cadmium (NiCd) batteries still accounted for 37%, a striking figure given that NiCd has been banned in new power tools sold in the EU since 2017. This persistence underscores how long these devices circulate in the market.

For batteries with a traceable manufacturing date, the average journey from factory to collection point spanned about ten years. Some dated back to 1989. Consumer-owned batteries took roughly eight years to return, while commercial tools came back after approximately four years.

Technical potential exists, but reuse rates tell a different story

Around 70% of all sorted power tool batteries were deeply discharged, largely due to older NiCd units. The picture shifts dramatically for lithium-ion: about half retained meaningful charge, with newer models holding even higher states of charge. This suggests the recycling stream includes batteries that may still have service life ahead and could merit evaluation for reuse.

BDS tested 265 used 18-volt battery packs through visual inspection, voltage measurements, and state-of-health (SoH) assessment via charge-discharge cycling. The results proved disappointing: 62% were deeply discharged, and more than one-third read below 4 volts, signaling potential irreversible cell damage. When the team evaluated two distinct return streams—one tied directly to a manufacturer and another through general take-back systems—they found 30% and 11% of packs suitable for reuse, respectively. However, these subsamples contained only 64 and 19 packs each, limiting their representativeness.

Economics and regulation block the path to scale

Low reuse rates create a fundamental business problem. Under German labor-cost assumptions, the expense of testing equipment and personnel would likely exceed revenue from selling refurbished packs. The final report indicates that commercial viability would demand more precise presorting, automated testing, or fundamentally different acquisition terms for used batteries.

Regulatory hurdles compound the challenge. Once consumers discard batteries, they become classified as waste and can only go to certified waste-management firms. Power tool manufacturers typically lack these certifications. Unresolved questions about liability, warranty coverage, and the brand identity of refurbished products further complicate matters. Standardized testing and reuse protocols remain absent.

Battery engineering itself presents obstacles. Power tool packs prioritize durability and safety over disassembly ease. Adhesives and material diversity make refurbishment labor-intensive. The project's conclusion is measured: second-life applications are technically feasible, but regulatory, operational, and financial barriers currently prevent widespread deployment.

High-value recycling emerges as the primary pathway

The research team expects most spent NMC power tool batteries to flow into Loop 2 (hydrometallurgical recycling), provided sorting and identification improve. Refurbishment is projected to handle the second-largest share, with pyrometallurgical processing taking the smallest fraction.

ERLOS conducted practical trials on Loop 2 processes. Since battery management systems typically prevent full discharge, the company developed a wet-discharge method that reduced pack voltage below 1 volt within 24 hours, with zinc salt added to limit corrosion. Testing revealed that mixed batches of NMC and nickel cobalt aluminum (NCA) batteries can enter the same hydrometallurgical stream. Process quality depends more on removing contaminants like plastics and electrolyte residue than on exact cathode chemistry—making early separation of lithium-ion from other battery types crucial.

From one matrix to three decision trees

EASLi initially aimed to build a single multicriteria assessment matrix to route each battery to its optimal recovery pathway. The project team discovered this approach had limited practical value: collection sites, sorting facilities, and refurbishers access different information and face distinct operational constraints.

Instead, the team created decision trees for three actual decision points in the process. At collection sites, basic questions guide initial sorting: Can the battery chemistry be identified? Is the housing damaged or contaminated? Are contacts intact and the manufacturer identifiable?

Sorting facilities then distinguish between chemistries, while refurbishers add assessment of charge state and SoH. This framework helps smaller operators direct batteries appropriately without demanding extensive data collection.

EASLi highlights a frequently overlooked dimension of battery recycling: recovered material quality depends not only on recycling technology but on how batteries are handled before recycling starts. Genuine circularity begins with the information available about each battery and how early different material streams are separated.

Data and automation could shift the equation

The project identifies potential in better data access and automated identification systems. A digital product passport or QR code could encode manufacturer, battery chemistry, capacity, and production date. Power tool batteries currently face no such requirement. Starting February 2027, the EU Battery Regulation mandates digital passports for electric-vehicle batteries, light transport batteries, and industrial batteries above 2 kWh—but not portable batteries. Camera-based AI could identify battery types and assess external condition. The project sketches an app concept using photographs to help determine whether a battery should go to reuse or recycling.

EASLi does not predict that second-life applications will soon displace recycling for power tool batteries. Instead, the findings point toward a more nuanced circularity strategy: identify batteries capable of continued use, remove unsuitable units early, and process the remainder to return the highest-value materials to battery production.

Source: Battery-News