Advanced vacuum systems improve battery recycling efficiency, recover valuable raw materials and support a more sustainable circular economy.
Vacuum technology is playing an increasingly important role in lithium-ion battery recycling, helping recover valuable materials while improving process safety and energy efficiency. Leybold, a specialist in vacuum technology, provides solutions for several stages of battery manufacturing and recycling, including slurry degassing, electrode drying, battery filling, leak testing and the safe drying of battery cells before material recovery.
According to Leybold, mechanical recycling can achieve recovery rates of up to 95%, depending on the process and materials involved.
Three Main Battery Recycling Processes
Lithium-ion batteries can be recycled through three primary processes: pyrometallurgy, pyrolysis and mechanical recycling. Each offers different recovery rates and material-recovery capabilities.
- Pyrometallurgy
Pyrometallurgy uses high temperatures to process battery cells in a furnace. The process produces an alloy containing metals such as cobalt, nickel and copper, sometimes alongside iron. Aluminium and lithium remain in the combustion slag, while graphite and plastic components are largely burned.
The recovered alloy can be further processed to extract reusable metals, with overall recycling rates reaching approximately 50% by mass.
- Pyrolysis
Pyrolysis decomposes battery materials at lower temperatures than conventional high-temperature smelting, in the absence of air. The process requires treatment of the resulting exhaust gases and is energy-intensive. However, it can enable aluminium recovery, increasing the recycling rate to approximately 60%.
- Mechanical Recycling
Mechanical recycling involves discharging and dismantling batteries before crushing them into smaller fractions. Discharging helps reduce the risk of uncontrolled reactions during shredding, while the remaining stored energy may contribute to the plant’s energy requirements.
Battery modules are crushed in a nitrogen atmosphere or under vacuum to prevent ignition of flammable electrolyte solvents. Vacuum technology is then used to dry the material at lower temperatures while safely extracting solvent vapours for condensation and potential reuse.
According to Leybold, mechanical recycling can achieve recovery rates of up to 95%. Following drying, a material known as black mass—a fine mixture of valuable battery materials—is separated from foil and plastic residues. The black mass can then undergo hydrometallurgical processing to recover lithium, nickel, cobalt, copper, graphite and other materials.
Reliable Vacuum Pumps Are Essential for Safe Processing
Battery recycling presents significant technical challenges, particularly because electrolyte solvents can produce flammable vapours. Vacuum pumps must therefore handle condensable and potentially aggressive vapours while preventing leaks and the formation of combustible mixtures.
Leybold’s solutions incorporate hermetically sealed pump housings and robust shaft-sealing systems designed to prevent process gases from escaping and air from entering the system. These features help improve operational safety and protect equipment during vacuum drying.
The company offers several vacuum technologies for battery recycling applications. Its DRYVAC series features dry-compressing screw pumps designed to handle condensable vapours. SCREWLINE pumps are suited to demanding applications where contamination and deposits can develop, while the RUVAC WH series of Roots blowers provides high suction capacity at low pressures.
Leybold also supplies complete vacuum systems incorporating pumps, condensers, storage arrangements and measurement and control technology.
System Design Determines Efficiency
Properly sizing vacuum systems is critical to achieving efficient drying. The required pumping capacity and condenser design depend on the specific dryer, operating pressure and solvent mixture.
Leybold’s Sebastian Rosensträter, Application Manager in its Industrial Division, explains that simply installing a larger vacuum system does not necessarily accelerate drying. The rate of evaporation depends significantly on the energy supplied to the dryer, making system design and process optimisation essential.
Reliable equipment, low maintenance requirements and energy-efficient operation are also important because downtime in the drying stage can interrupt the entire recycling process.
Growing Demand Creates Opportunities for Battery Recycling
The expanding use of electric vehicles, consumer electronics, household appliances and power tools is expected to increase the volume of lithium-ion batteries requiring end-of-life management.
Rosensträter notes that sufficient batteries are already in circulation to support commercial recycling opportunities, while future growth in discarded batteries is likely to increase demand for industrial recycling capacity.
Battery reuse through second-life applications, such as converting electric-vehicle batteries into stationary energy storage systems, can extend their useful life. However, these batteries will eventually require recycling to recover their remaining valuable materials.
Recycling Offers an Alternative to Mining
Recovering battery materials can reduce reliance on the extraction of virgin raw materials, including lithium, nickel and cobalt. Mining these resources can be expensive, technically complex and environmentally damaging.
Efficient recycling can help return valuable materials to the supply chain, supporting resource conservation and a more circular battery economy. Leybold highlights that the commercial viability of recycling depends on combining effective material recovery with safe, reliable and energy-efficient industrial processes.
Managing Chemical and Explosion Risks
Battery recycling facilities must also address the risk of explosive atmospheres and hazardous chemical reactions. ATEX requirements apply to equipment used in potentially explosive environments where flammable gases, vapours or mists can mix with air.
During battery shredding, nitrogen inerting helps reduce ignition risks. Properly sealed vacuum systems can further limit air ingress and process-gas leakage, although equipment requirements must be assessed for the specific installation.
Another concern is hydrogen fluoride (HF), a toxic and corrosive gas that can form when certain fluoride-containing battery salts react with moisture, particularly under heated conditions. Maintaining dry process conditions helps reduce associated risks and potential corrosion within the plant.
With its range of vacuum pumps, blowers and integrated systems, Leybold supports battery recyclers in developing processes that prioritise safety, operational reliability and resource recovery as global demand for lithium-ion batteries continues to grow.
