One of the biggest concerns about electric cars is what happens to the batteries
They are historically difficult to recycle and could result in waste mountains . BMW UK has partnered with Off Grid Energy to provide second-life solutions for batteries decommissioned from its electric cars. Batteries are being used by the energy storage firm for mobile charging stations. Prototype device has been built using lithium-ion modules from a Mini Electric.
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.
BMW i3 and i3S 120Ah (Image: BMW Group)
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.’
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