What should happen to lithium-ion batteries from electric cars at the end of their lifecycle? They’re much too good to be thrown away.
Green for go: e-mobility is rapidly picking up speed all over the globe. In the future millions of electric and hybrid vehicles will be powered by millions of batteries. However, their service lives decrease over time. Battery performance and lifetime depend on a large number of factors, for example the frequency of charging and discharging, the charging procedure, the user’s driving style and external influences such as temperature. So every lithium-ion battery ages and loses storage capacity during its useful life. If the capacity falls below a certain defined value, the battery has reached the end of its life. A limit of 80 percent has become established throughout the industry – the manufacturers also use it when drawing up their battery guarantees. But determining a battery’s “state of health” requires complex measuring technology. Bosch has brought out a cloud-based battery monitoring system that collects and analyzes data from batteries, which is generated in the electric car fleet, in order to deliver precise forecasts of their service life. The startup Twaice has launched its battery analysis software for a computer simulation to assess the quality of used lithium-ion batteries. This allows predictions about the future. The battery experts at the University of Warwick are taking a different approach. They have developed a classification method for Nissan. In just a few minutes it determines whether batteries taken out of service should be used for spare parts, given a “second life,” or recycled.
But one thing after another. What should happen to the millions of old lithium-ion batteries? One widespread approach is to find “second life” applications for them. Batteries can store energy from renewable sources and stabilize the grid. Stationary operations are far less demanding than electric cars that continually stress their batteries during acceleration and recuperation. As early as 2016, Daimler built a stationary storage system out of 1,000 old batteries from electric smart fortwo cars, and made a name for itself with battery storage solutions. Its subsidiary Mercedes-Benz Energy recently started cooperating with the BAIC Group on increasing the popularity of such “second life” energy stores made from old vehicle batteries. The competitors BMW, Bosch and Vattenfall tested the re-use of batteries for an energy storage system in Hamburg’s harbor up to the end of 2018. Around 2,600 battery modules from more than 100 electric BMW vehicles – the ActiveE and BMW i3 – were connected to create a storage system. It has a capacity of 2,800 kilowatt hours (kWh) and stores energy to balance out fluctuations in the electricity grid. It could supply an average two-person household with electricity for seven months. BMW has set up a stationary battery storage farm at its plant in Leipzig, consisting of 700 batteries from i3 cars; some of the batteries are second-hand. The aim is to harness the company’s own solar and wind power for use in production.
Nissan and the Brazilian Federal University of Santa Catarina have teamed up to research second-life applications. For example, used batteries are providing energy storage in residences. The Johan Cruijff Arena in Amsterdam will become first stadium in the world to secure its energy supply through a storage system made from new and used EV batteries. Here Nissan and its partners have set up one of the largest energy storage systems for a commercial building anywhere in Europe. It consists of new and used batteries from Nissan’s small Leaf, which are charged up with solar energy. The storage capacity of three Megawatts can theoretically supply several thousand households or half a million iPhones with electricity for one hour. In Fukushima Prefecture in Japan, Nissan has installed street lamps powered by solar collectors and old batteries. The outdoor lighting does not require cables or sockets, and operates totally off-grid. Renault is supporting storage projects in France and Germany with old batteries from the Zoe. And in VW’s fast charging stations, used batteries are being repurposed as stationary storage. Volvo uses the second-hand batteries from its electric buses to supply homes in the Swedish city of Gothenburg. Audi has installed a 1.9 Megawatt hour storage unit (with e-tron batteries) for research purposes on the EUREF science campus in Berlin. Old batteries have many applications. A “second life” harbors huge economic potential, according to a study by the consulting firm Berylls Strategy Advisors. It calculated that by 2032 a capacity of around 1,500 Gigawatt hours will be available from used batteries.
Yet at some stage even these batteries give up the ghost. For this reason companies, research institutes and vehicle-makers are developing and optimizing efficient ways of recycling high-voltage batteries. This is not only ecological, but also makes economic sense. The batteries contain valuable raw materials such as cobalt, nickel and rare earths. Up to now, most OEMs collected their used e-car batteries and gave them to special recycling companies. The manufacturer Audi has been involved with recycling since it began developing its first fully electric cars. Together with the Belgian materials technology and recycling group Umicore, Audi has been researching specific procedures since 2018. More than 90 percent of the cobalt and nickel from the high-voltage batteries of the plug-in hybrid A3 e-tron was recovered in laboratory tests. The companies are now adapting the concept for the e-tron’s new model series. Other manufacturers are now also addressing this topic. Tesla is currently establishing its own system at its Gigafactoy 1 in Nevada. Nissan has built a recycling facility in Japan. VW installed a pilot scheme at its battery plant in Salzgitter. It has been recycling batteries since 2020 – initially 1,200 tons a year, which equates to 3,000 vehicle batteries. The Volkswagen Group has set itself a very ambitious long-term target – to recycle 97 percent of all its raw materials. Its partner for battery cells, the company Northvolt, has set up a plant in Sweden. And Jeffrey Straubel, Tesla’s former Chief Technical Officer, recently founded the startup Redwood Materials to muscle in on the recycling business.
Umicore recycles approx. 7,000 tons of lithium-ion batteries from smartphones, e-bikes and electric cars every year. The metals can be extracted by heating the battery modules containing them in a smelter in the ultra-high-temperature furnace to around 1,400 degrees, until the metals melt and form an alloy. Cobalt, nickel and copper can be separated out owing to their different melting points and densities, and prepared for other processes. In this way the company achieves a recycling quota of 95 percent. The slag also contains lithium. In Germany there are a handful of businesses recycling lithium-ion batteries. Modern systems such as the one at Redux Recycling in Bremerhaven are able to recycle over 10,000 tons of lithium-ion batteries every year. The recovery rate – the share of starting material that can be re-used – reaches 60 to 70 percent. The especially valuable materials include copper and aluminum, which are used as conductors or in battery housing; or the active materials from the anode and cathode, which frequently consist of cobalt, manganese and nickel.
The Krefeld firm Accurec currently recycles half of all Europe’s lithium battery waste. First of all the plastic cases, the metal parts such as copper cables and circuit boards are removed manually, sorted and partially recycled. The actual battery is heated to 600 degrees. This burns off the electrolyte and any remaining plastic. In the next step, a special machine rips the batteries open. The constituents are separated by magnets and blowers. Other methods are being used, too. At VW the individual parts are first shredded, and then the material is dried and sieved. The resulting black powder contains the valuable metals nickel, manganese, cobalt and lithium. It only remains for them to be separated. After that, they can immediately be used in the production of new batteries. Numerous research institutes are already working on new procedures that consume less energy. This will result in a new hi-tech branch of the circular economy with key innovations from players in Germany.
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