Retired electric car batteries to be used in mobile charging stations

One of the biggest criticisms of electric cars is what happens to their high-powered batteries once they degrade and have to be decommissioned from plug-in vehicles.

Not only are EV batteries expensive for owners to replace, high-skilled workforces are required to extract valuable metals inside them, and even then they are difficult to recycle – and this could lead to huge waste mountains, experts have warned.

German car maker BMW says it has found a resolution for its high-mileage electric vehicles, giving their batteries a second-life use as mobile power units to provide charging solutions for other plug-in cars.

The auto brand will supply a British energy storage firm with decommissioned battery modules from electric BMW and Mini models that can be used in mobile power units.

The aim is to provide a sustainable second-use model for the batteries, which lose capacity over time and after years of use are deemed no longer efficient for electric cars. 

As part of a new partnership with the car giant, Off Grid Energy has produced its first prototype mobile charging device, which is powered by lithium-ion battery modules extracted from a Mini Electric development vehicle.

It has a 40kWh capacity delivering a 7.2kW fast charge and will be used at BMW and Mini UK events over the next year. 

As more battery modules become available over time, it says it can produce combined systems with a capacity of up to 180kWh from multiple electric vehicle batteries, which will be able to provide charges at rates of up to 50kW. 

‘When these units are used to displace conventional ways of generating temporary power, the battery modules will at least double the CO2 reduction achieved in their original use in the car, continuing their positive impact in reducing carbon emissions,’ says the energy storage company.

Commenting on the partnership, Graeme Grieve, ceo at BMW Group UK, said: ‘BMW Group will have 25 electrified models on the roads by 2023 – half of them fully electric. 

‘We are delighted to work with Off Grid Energy to find a sustainable way of continuing to use these valuable batteries, even after they have put in many years of service in our electrified cars.’

Like many electric models on the market, batteries in BMW and Mini cars have a warranty of eight years or 100,000 miles. 

After this period the battery could still retain up to 80 per cent of its initial capacity, according to the vehicle maker.

However, it concedes that it is ‘inevitable’ that as EVs get older their batteries will no longer function at an optimum level for the car.

According to battery degradation calculations by Canadian firm Geotab, the average capacity loss for electric and plug-in hybrid cars is an estimated 12 per cent after six years – essentially dropping 2 per cent capacity annually.

BMW says despite its car batteries declining in performance – significant enough to retire the unit from a vehicle – it can continue to serve a secondary use purpose as a mobile power source as part of its sustainability and resource efficiency strategy.

BMW Group ceo, Oliver Zipse, said: ‘How we use resources will decide the future of our society – and of the BMW Group. As a premium car company, it is our ambition to lead the way in sustainability. That is why we are taking responsibility here and now.’ 

Earlier this year, Warwick University announced it had created a ‘fast grading’ system for second-life car batteries to determine if they could be purposed after being decommissioned from vehicles, using Nissan Leaf EV power supplies for the study.

If the battery’s end of life capacity is less than 70 per cent, the report says they can be reused for less demanding second life applications such as domestic and industrial energy storage.

The university said: ‘Graded second-life battery packs can provide reliable and convenient energy storage options to a range of customers: from electric roaming products – providing electricity for customers on the move, to home storage products – enabling customers with solar panels to store their energy generated. 

‘More crucially, the packs can be used for storage allowing increased intermittent renewable energy sources on the grid, without putting security of supply at risk.’

Professor David Greenwood from WMG, University of Warwick, added: ‘Automotive batteries deliver some great environmental benefits, but they consume a lot of resources in doing so. 

‘Opening up a second life for batteries improves both the environmental and the economic value we draw from those resources before they need recycling.’ 

Threat of electric car battery waste mountains

Demand for new electrified cars is booming at the moment, with battery electric vehicle registrations up by 165 per cent year-on-year, and plug-in hybrids also increasing by 84 per cent. 

Latest industry figures show that 108,888 cars sold in Britain so far this year were battery-powered motors, accounting for 8.8 per cent of all new vehicles bought in the UK so far this year.

Experts have predicted their market share will increase to 12 per cent next year, as new UK regulations confirmed this week will force manufacturers to increase their sales of ultra-green models.

That compares to 719,908 cars with petrol engines and 209,093 with diesels.  

With both pure-electric and plug-in hybrid car sales surging, critics are growing increasingly concerned about the huge demand they will place on the National Grid, but also the impact on the environment given the difficulties of recycling batteries. 

Recent studies have warned that the huge uptake of electric vehicles in the lead up to the ban on sale of petrol and diesel cars – currently scheduled for 2040 but likely to be fast-tracked by a decade to 2030 – could result in ‘waste mountains’ of end-of-life lithium ion batteries.

A review of existing recycling measures in place suggests that while plug-in cars offer a solution to cut emissions, governments and industry need to act now to develop a robust infrastructure to dispose of decommissioned batteries or face a substantial waste management problem.

The research, led by the University of Birmingham, calculated that the 1million electric vehicles sold globally in 2017 will alone lead to 250,000 tonnes – or half a million cubic metres – of unprocessed pack waste when the cars reach the end of their lives.

Dr Gavin Harper, Faraday Research Fellow at the University of Birmingham, who is lead author on the research paper, said: ‘The recycling challenge is not straightforward: there is enormous variety in the chemistries, shapes and designs of lithium ion batteries used in EVs.

‘Individual cells are formed into modules, which are then assembled into battery packs.

‘To recycle these efficiently, they must be disassembled and the resulting waste streams separated.

‘As well as lithium, these batteries contain a number of other valuable metals, such as cobalt, nickel and manganese, and there is the potential to improve the processes which are currently used to recover these for reuse.’

Professor Andrew Abbott of the University of Leicester and co-author of the 2019 research, added: ‘Electrification of just 2 per cent of the current global car fleet would represent a line of cars that could stretch around the circumference of the Earth – some 140 million vehicles.

‘Landfill is clearly not an option for this amount of waste. Finding ways to recycle EV batteries will not only avoid a huge burden on landfill, it will also help us secure the supply of critical materials, such as cobalt and lithium, that surely hold the key to a sustainable automotive industry.’

While the research offered a stark warning to both ministers and the automotive sector, it also offers an enormous opportunity for the UK to create dedicated facilities specifically to recycle end-of-life batteries, which could boost the economy and create jobs.

It concluded there was a need for eight gigafactories in the UK by 2040 to service the demand for lithium-ion batteries.