Although China currently leads the world in EV battery recycling, the US has numerous initiatives underway, supported by the Inflation Reduction Act. Meanwhile, the UK and other European players also have a significant opportunity in the longer-term. Indeed, the European Battery Directive sets targets for collection and recycling of EV batteries.

The Faraday Institution points out in its latest Faraday Insights report (July 2024): ‘Creating a circular battery economy through recycling in the UK would not only reduce its dependency on importing critical materials… but also reduce carbon emissions, environmental costs and the need for mining virgin raw materials around the world.’

The UK Department for Trade and Industry’s (2023) Battery Strategy emphasises that ‘recycling will be a vital part of the development of a more secure and resilient battery supply chain’.

Prior to recycling and recovery of materials, there is a significant opportunity for re-use and re-purposing of EV batteries, for applications like battery energy storage systems (BESS) and powering light mobile transport systems, for example.

Disposal by dumping in landfill or incineration is considered to be the worst option environmentally. In fact, batteries are banned from incineration or landfill in the UK under the Waste Batteries and Accumulators Regulation 2009.

‘Recycling will be a vital part of the development of a more secure and resilient battery supply chain.’ – Department for Trade and Industry’s Battery Strategy (2023)

The battery recycling market  
EV battery life is estimated to be about 10–15 years, so most will not be ready for recycling before the mid-2030s. McKinsey estimates that the proportion of recycling from EOL batteries will reach around 83% of recycled battery material by 2040.

Currently, China is the world leader in battery recycling and is set to have 430 GWh of batteries available for recycling in 2035 due to early EV adoption – with established networks for battery collection, disassembly and recycling – compared to a global total of 770 GWh, according to Bloomberg NEF’s (BNEF) Li-ion Battery Recycling Market Outlook (March 2024). Europe and the US lag behind, with estimates of 140 GWh and 120 GWh available respectively for recycling by 2035.

According to the International Energy Agency (IEA), global demand for lithium is estimated to grow by 870% by 2040, with demand for graphite rising 390%, nickel by 210% and cobalt more than doubling to 220%.

Due to this surge, analysts at the Cleantech Group anticipate a parallel growth in the battery recycling industry, through several distinct, potentially non-competitive technologies, according to its new report on Battery Recycling and Material Innovation in APAC (May 2024). Furthermore, ‘battery manufacturers, automobile OEMs and refineries are creating localised supply chains to feed the surging demand for battery materials', notes Cleantech Group Waste & Recycling Analyst Parker Bovée.

Battery recycling processes  
There are three major processes for the recovery of value adding materials from EV batteries: pyrometallurgy, hydrometallurgy and direct recycling.

Pyrometallurgy has a relatively low lithium recovery rate, in an energy intensive process with high emissions. Thermal treatment at 140–500°C removes volatile electrolytes and organic solvents prior to smelting at 1,400–1,700°C, yielding alloys of cobalt, copper and nickel, and an oxide slag containing lithium and aluminium, which can be purified by leaching and solvent extraction.

Hydrometallurgy provides higher recovery rates, using less energy but involving complex chemical processes and higher emissions of greenhouse gases. European companies such as Umicore (Belgium) use pyro- and hydrometallurgy; Glencore (Switzerland) uses hydrometallurgy; and Accurec (Germany) uses pyro- and hydrometallurgy processes.

Although direct recycling promises high material recovery with minimal environmental impact, it is still at an early stage of development. The process involves repairing the cathode of an EV battery, by supplementing lithium salts.

‘Direct recycling could potentially yield a high value product stream with a low energy consumption and few post-processing steps,’ according to a review in Resources, Conservation and Recycling (January 2023). However, unlike pyro- and hydrometallurgy, the cells require physical disassembly to recover battery components.

Economics of battery recycling  
The global Li-ion battery recycling market is expected to reach $40.6bn by 2030, with hydrometallurgical process recycling accounting for 65% of the total, according to Allied Market Research’s Li-ion Battery Recycling Market Outlook (2022).

The commercial viability will depend on process efficiency, disassembly costs, battery chemistry, the market price for recovered materials, energy costs and collection costs. However, as recycling material availability increases, economies of scale will kick in.

UK recycling industry  
The UK has begun to develop a battery recycling industry with pilot-scale plants, pre-treatment and treatment facilities for the undifferentiated components, the so-called ‘black mass’. Recyclers for pre-treatment include Ecobat, Veolia, EMR, Lithium Battery Recycling Solutions and others. Black mass treatment companies include Altilium, Cellcycle and ICoNiChem.

Start-ups tend to specialise in second-life applications or fast-charging processes.

As of 2021, there were 32 established or planned Li-ion battery recycling facilities worldwide, with around 400,000 tonnes of recycling capacity, according to ACS Energy. As mentioned, over two-thirds of recycling capacity is in China. In Europe, companies such as Umicore, BASF and Veolia have the capacity to recycle batteries at scale.

Re-use and repurpose of EV batteries  
It is estimated there will be 85 million EVs in operation globally by 2030. However, once EV batteries degrade to 70–80% of their initial capacity, they have to be replaced as the residual capacity is insufficient for automotive vehicle use. These batteries can be repurposed as second life batteries (SLBs), but require skilled and careful testing before repurposing, as Li-ion batteries are categorised as Class Nine hazardous material.

Studies have been carried out in many countries, and one of the most comprehensive is published by the Alexandria [Egypt] Engineering Journal: ‘Feasibility of utilising second life batteries’ (March 2021).

According to BNEF, it is estimated that the cumulative capacity of used EV batteries could reach 185.5 GWh/y by 2025. Another study estimates that total SLB capacity could reach almost 1,000 GWh by 2030.

‘Li-ion batteries have high power density, fairly long lifetimes and low self-discharge, which accounts for their popularity as energy storage in portable/electronic products,’ note the University of Alexandria researchers.

The percentage of residual capacity represents the battery state of health (SOH). Degradation is estimated to happen after 5–8 years, equivalent to 100,000 miles (160,000 km) of travelling. However, retired EV batteries can be repurposed in other applications: for example, as battery storage in residential households or to handle power variance in grid-scale photovoltaic (PV) plants – adding another 7–10 year lifespan.

A host of applications  
Faced with growing environmental concerns, engineers and policymakers are considering a wide variety of applications using used SLBs. The Alexandria report highlights:

• On-grid applications such as area and frequency regulation, load levelling, generation-side asset management, peak reduction and reactive power support, and as a renewable energy supply for farming.
• Off-grid applications: microgrids, smart grids, load following and power reliability.
• Mobile applications: EV charging stations, for EV bicycles and scooters, vehicle-to-grid for fast charging, and as EV for longer-range trips.

Power storage applications  
The disruption to EV charging caused by power outages is becoming a real concern. To address this issue, Tesla developed the Powerwall, which features a battery pack powered by solar panels to store energy for use during power outages, both for home use, public and private EV charging, and behind-the-meter applications.

Nissan and 4R Energy Corporation used discarded batteries from Nissan Leaf EVs for re-use in EV battery packs, after categorisation into three grades – where Grade A is excellent condition, Grade B are suitable for forklifts and large ESS, and Grade C could be used in back-up supply power units.

BMW has partnered with Bosch and energy company Vattenfall to connect over 2,600 battery modules from over 100 BMW EVs to form an ESS. The first ESS, made from BMW i3 batteries, was built on the 122 MW Princess Alexia onshore wind farm near Amsterdam in the Netherlands, with a capacity of 3.2 MW – enough to supply 88,000 households with clean electricity when the weather is calm.

In Germany, 2,000 retired batteries from Mercedes EVs were dismantled to form a stationary 9 MW battery. In a similar project, SLB packs from 85 used Toyota Camry Hybrid cars provide 85 kWh of storage capacity for a PV system at a buffalo ranch in the US.

At the other end of the spectrum, German-Indian start-up Numan has brought electric rickshaws to Indian roads powered by used batteries from test vehicles in the Audi e-tron test fleet, as a second-life project.

• Further reading: ‘Europe’s largest closed-loop hydrometallurgical battery recycling facility opens’. Fortum Battery Recycling’s new recycling facility in Finland is capable of recovering 95% of valuable and critical metals from a lithium ion battery’s black mass, returning them to the cycle.  
• Much like wind turbines and recycling bins, the rise of electric vehicles (EVs) is symbolic of the commitment towards reducing the global carbon footprint. Cameron Leslie, Mechanical & Electrical Engineer at Xodus-Academy, reports on developments in EV battery technology.