Electric cars are a critical subject, and are likely to remain so as buyers respond to knee-jerk legislation by turning to electric vehicles (EVs) – be it plug-in hybrid or pure electric. Sales of those cars eligible for the (now reduced) government plug-in car grant are up 30 per cent year-on-year in the UK according to the SMMT, with 26,482 registered in the first half of 2018.
Notwithstanding the issues of excavating precious metals, there is a significant environmental burden associated with plug-in cars that must be considered: the batteries.
The scale of the issue
Most modern EVs use lithium-ion batteries; much the same as those that power your phone, toothbrush, tablet and most portable electrical items. Given how unfathomably numerous these small batteries are, it says a lot that EV batteries are expected to account for 90 per cent of the lithium-ion battery market by 2025 according to a recent forecast by consultancy firm Roskill.
For a longer-range forecast, consider that the UK government intends for all new cars and vans to be plug-in EVs by 2040. Assuming the new car market remains as buoyant as it is now, that equates to about 2.5 million new cars – and therefore battery packs – each year.
While the sheer volume of EV batteries that will need to be re-purposed or recycled is undoubtedly daunting, it’s worth starting on the positive note that these batteries have a long lifespan, and have proven very reliable. Most lithium-ion batteries will last about eight to 10 years before their performance drops to around 70 per cent (or less) of what it was when new.
So what can be done with these batteries when they reach the point that they need to be re-used or recycled?
Power storage for your home and business
One popular solution is to re-use them as power storage for domestic and commercial buildings. Nissan recently launched the largest power storage facility in Europe to use both new and used car batteries; the Johan Cruyff ArenA in Amsterdam uses 63 used EV battery packs and 85 new battery packs, which feed off of 4,200 solar panels on the stadium roof.
This does not mean that the ArenA is entirely “off grid”. It still relies heavily on mains power, but the EV battery-powered energy storage system acts as a back-up generator that can run the stadium during a major event (the equivalent power drain of around 7,000 homes) for up to an hour. It will also be used to back up the stadium’s energy supply during times of heavy power usage, which will reduce the drain on the grid.
Nissan also offers an off-the-shelf home or commercial energy storage unit called xStorage – a rival to the Tesla Powerwall 2 system – although Nissan’s is different in that you can choose to have used or new EV batteries.
As with the ArenA, getting solar panels and a Powerwall 2 or xStorage system fitted to your home doesn’t actually mean that you’ll be “off grid”. Rather, it will significantly reduce your dependence on mains power, reduce strain on the grid at peak hours and, of course, you can use it charge your EV.
There’s an appealing circuitousness to the situation if used EV batteries can provide a home energy solution to solve the potential issue of increased electric car charging putting too much strain on the power grid at certain times.
Even so, energy storage is not a one-shot solution for the used EV battery issue, and some don’t think it’s a solution at all.
Transport applications require a highly energy-dense battery to provide the necessary range, which makes batteries that contain cobalt very desirable, but stationary energy storage units don’t need to be so compact and relatively light. Cobalt is a critical issue in battery production. Much of it is sourced from the Democratic Republic of Congo, where the mining process raises serious ethical and human rights concerns. This is likely to be one of the greatest challenges as demand for lithium-ion batteries rises.
Dr Gavin Harper, a Faraday Institution Research Fellow at the Birmingham Energy Institute’s project on recycling and reuse of lithium-ion batteries, stated that “if we face constraints around cobalt, some feel we should focus this precious resource on more demanding applications such as EVs. It may make more economic sense to recycle EV batteries for use in brand new batteries rather than using them in a used state in a less demanding application [such as power storage]”.
Mercedes-Benz would agree. The German manufacturer also launched a home energy storage system using lithium-ion batteries from its range of EVs in April 2017, but the product was axed only a year later, with the company claiming that “it’s not necessary to have a car battery at home. They don’t move, they don’t freeze, it’s overdesigned.” So, for Mercedes-Benz at least, the costs didn’t add up.
Nissan, however, is adamant that EV battery technology is transferable to home use. A spokesperson stated that Nissan “is committed to operating in the energy services market and is strongly placed to utilise both new and second life EV batteries for energy storage in a way that is commercially viable”.
Tesla is also heavily invested in home and commercial energy storage with its Powerwall 2, although this uses new, rather than used, batteries.
What about recycling them?
Recycling EV batteries is difficult but not impossible. It’s not like a standard petrol or diesel car’s lead-acid battery (used for starting the engine), which can be smashed up and have the plastics and lead recycled easily.
Belgian-based Umicore is among the companies already offering recycling for lithuim-ion batteries, reclaiming the valuable metals using a process based on the combination of pyro-metallurgy and hydro-metallurgy. While the company currently runs a pilot plant, it can still recycle about 35,000 EV batteries per year and, according to a company spokesperson, “can easily scale up our recycling activities when the market grows, which we expect to happen in 2025”.
Even better, metals are infinitely recyclable, so they can be reclaimed from used batteries and employed to produce new batteries that are as good as any other.
Tesla is also open about its intentions to recycle its batteries in this way, to the point where recycled metals from its batteries would negate the need to mine new metals. Tesla’s chief technical officer JB Straubel said earlier this year that Tesla is “developing more processes on how to improve this recycling process to get more of the active materials back and, ultimately, what we want is a closed loop that reuses the same recycled materials. That is where we are headed with this”.
Another aspect for manufacturers to consider is to actually design batteries for recycling. For example, Tesla’s batteries are constructed using an epoxy resin that makes recycling problematic. Dr Harper points out that “if we want to move towards a circular economy of batteries, we need to ‘design out’ the recycling challenges”.
What if other battery technology replaces lithium-ion?
There’s significant interest around sodium-ion batteries, which are similar to lithium-ion ones except that sodium is much more widely available – and cheaper. These batteries would be similarly recyclable to lithium-ion items.
The other big hope for the future is solid state batteries. This battery tech uses a solid electrolyte (the chemical mixture that allows and regulates the flow of current) rather than the liquid electrolyte used today, which promises to make the batteries safer and able to provide more energy. Toyota, BMW and Dyson are among the significant players which have stated a clear intent to be using solid state batteries in the near future.
According to Peter Slater, professor of materials chemistry and co-director of the Birmingham Centre for Energy Storage, the recyclability of solid state batteries “would present different challenges in terms of separating the components. In particular, it is likely that it would need chemical separation routes, such as those being developed through the Faraday Institution’s ‘ReLib’ project”.
Ultimately, if the appalling environmental implications of putting batteries into landfill weren’t persuasive enough, the other cold truth is that the metals they contain are too valuable to waste.
So, while there may be many and varied answers to the question of “where do used EV batteries go?”, ecological and economic good reason are unanimous on one thing: not into the ground.
