Sustainable alternatives series Breathe in a second life: How EV batteries can be reused and recycled

The battery is at the heart of every electric vehicle. So what happens, if it stops working as it should? If a battery’s performance drops, it often needs to be replaced. However, the battery’s life cycle does not end here. In this article we reveal the second life of an EV battery and what happens afterwards.

The lifecycle of a vehicle’s battery has it’s limits: After eight to ten years or approximately 99,400 miles; performance usually drops below 70 percent. The battery may no longer be suitable for use in the vehicle – but it still has plenty of power that can, and should, be harvested. 

The first step is to check whether the battery can be used in another vehicle after remanufacturing. To achieve this, individual cells are replaced and the battery can be reused as a replacement or other in applications. Remanufacturing  avoids the production of a new battery and reduces the amount of waste, saving energy and raw materials. 

Extending a battery’s life cycle

When batteries are not able to be remanufactured and reused in vehicles –due to insufficient residual capacity, for example – there is another solution to extend their life cycles.  Second life battery storages use the remaining energy in a battery’s cells. These storages provide concentrated energy and can cater to the grid. 

BMW Group’s co-operation with Bosch and energy company Vattenfall demonstrates how batteries can be used as flexible energy storage devices to help ensure grid stability. Together, the companies have connected around 2,600 battery modules from more than 100 BMW electric vehicles to form a power storage system in their Second Life Batteries project. The first storage facility made from BMW i3 batteries has been built at the 122 MW Princess Alexia onshore wind farm, near Amsterdam. With a capacity of 3.2 megawatts (MW), it is Vattenfall's first large-scale storage project in the Netherlands, supplying 88,000 households with clean electricity. The added battery capacity helps store electricity from the wind turbines, so that the wind farm can continue to supply electricity even when the weather is relatively calm. 

Mercedes-Benz , together with technology company The Mobility House AG have built one of the largest secondlife battery storages in Northrhine-Westphalia, Germany. A total of 1,000 batteries – all from electric Smart Fortwo models – are bundled into a huge storage system with a total capacity of twelve megawatts. The battery park is connected directly to the power grid and can store or release energy as needed. The power generated by the system is enough to light up all the street lamps in a city with over a million residents.

Meanwhile, Audi has joined forces with German-Indian start-up Numan to launch the recycling of battery packs in  tuk-tuks. Their aim is to convert the characteristic three-wheeled vehiclesfrom combustion engines to electric . This collaboration helps support the Indian government in their strategy to go electric in the coming decades.

Battery storage systems can compensate for fluctuations in the power grid to guarantee the balance of supply and demand. If there is too much electricity in the grid due to fluctuations in production or demand, the batteries store the surplus. And then when there is a shortage of electricity, the batteries supply it within seconds. After about ten years, the power of a battery cell in second-life use is completely exhausted. The battery’s second life comes to an end and the reusable material is recycled back into the production cycle. 

These are only a few examples of what can be achieved. New ideas and technologies that enable us to give batteries a second life are constantly being discovered. 

Recycling: closing the material cycle

Did you know that up to 99% of a battery is recyclable? Tapping into innovative recycling methods is pivotal for a sustainable business model for emobility. Battery housings, cables, and busbars can be recycled quite easily. The battery modules, which contain a large proportion of the rare materials, are more challenging. Existing processes still need to be refined so that the valuable raw materials in the battery cells can be recovered as purely as possible. However, today, various complex recycling processes make it possible to reuse the majority of the materials for the production of new car batteries. The recovery process usually contains three steps: 

• Separating: The outer plastic shell and any other internal plastic components are separated from the metal components. These are all valuable parts that can be used to make new batteries.
• Shredding: The aluminum case, electrode material, and separator foil are then ground into very small pieces in a special shredder. 
• Smelting: The most valuable materials - metals like lead, nickel, and cobalt - are separated using two different processes: pyrometallurgy and hydrometallurgy. Pyrometallurgy involves shredding and burning the cells and other components of the battery, while hydrometallurgy uses acid to dissolve them.

Once separated, the recycled materials go to a battery manufacturing plant where they make up about 80% of new batteries. Today, the majority of EV batteries are currently used in vehicles or second-life storage systems, so it will be a while before large numbers of old batteries can be recycled. For the automotive industry, the aim is to further optimise recycling processes. The are still some technical problems that need to be solved when it comes to recycling lithium and cobalt, for example. In the case of lithium, recycling is not yet economical as newly mined lithium is still cheaper than the raw material from recycling. However, as  the number of electric cars continues to increase each year, this is expected to change.