In an era of significant economic and geopolitical uncertainty, the persistent growth of the global EV market is quite remarkable. Global sales of electric cars are on track to surpass 20 million in 2025, accounting for over a quarter of cars sold worldwide. Increased demand has primarily been attributed to improved affordability, driven by growing competition, declining battery costs and cheaper running costs in comparison to conventional combustion-engine cars across several markets.
As a result, there is now an unprecedented demand for lithium-ion batteries –- a key component of EVs, which is set to increase 14 fold by 2030. Amid escalating geopolitical and global trade tensions, this is potentially problematic for countries such as the US, which rely heavily on imported lithium-ion batteries from China.
While ramping up domestic lithium-ion battery production may appear to be the obvious answer, the extraction of raw materials such as lithium, cobalt and nickel for EV batteries comes at a huge environmental cost. Extracting just one tonne of lithium from hard rock mines can emit up to 15 tonnes of carbon dioxide and the mining of cobalt can cause pollution.
Recycling EV batteries, however, would allow countries to enhance their resource security without causing significant environmental damage and jeopardizing their decarbonization targets. The potential impact of scaling domestic battery recycling capacity is not to be underestimated. According to the International Energy Agency (IEA), recycled materials could help meet up to 30% of the global demand for key battery metals by 2040.
Yet the complexity of EV batteries poses several challenges for recycling in relation to mineral recovery, safety, and economy viability. The economics only add up if recycling plants are able to extract and process the target materials efficiently, which requires advanced filtration methods.
The pursuit of purity
Advanced filtration systems play a critical role in all three of the main methods for recycling lithium-ion batteries –- direct recycling, pyrometallurgy and hydrometallurgy. The latter is often the preferred method due to its higher material recovery rates, lower energy consumption, reduced greenhouse gas emissions, and minimal air pollutants compared to pyrometallurgy. Hydrometallurgy is also easier at a commercial scale than direct recycling, which can face challenges if batteries are not adequately labeled.
In hydrometallurgy, used batteries are crushed and shredded into a dark powder called ‘black mass’, which is mechanically separated from other battery components such as the casing, separator membrane and metal foil electrode. The black mass is treated with sulfuric acid to dissolve the lithium, cobalt, nickel and any other metals present such as manganese. Effective filtration is needed to separate any insoluble graphite materials from the acid solution containing the metals. The acid solution is then treated by one of three methods - chemical precipitation, solvent extraction, or adsorbent beds - to recover the metals for re-use, all of which rely heavily on advanced filtration systems.
Crucially, by removing solid particles and contaminants from the acid solution in hydrometallurgy, filtration helps to maintain the purity of recovered metals, increasing their economic value and boosting the incentive to recycle more. Filtration therefore plays a vital role in ensuring the economics of battery recycling add up, making producers less reliant on environmentally destructive alternatives such as mining critical minerals from the ground. Ultimately, enhancing battery recycling capabilities not only supports countries in meeting their decarbonization goals but also paves the way for a more resilient and self-sufficient EV industry.
Anoop Survana is Global Battery Materials Manager at Pall Corporation.