A group of scientists from Chalmers University of Technology (Sweden) has developed a new method to recover metals from electric vehicle batteries at the end of their useful life.
New formula to recycle batteries effectively and sustainably
Researchers at Chalmers University of Technology (Sweden) have presented a new and effective way to recycle metals from used electric car batteries.
The method allows the recovery of 100% of aluminum and 98% of lithium from electric car batteries. At the same time, the loss of valuable raw materials such as nickel, cobalt and manganese is reduced. The process does not require expensive or harmful chemicals because the researchers use oxalic acid, an organic acid found in the plant kingdom.
In Chalmers’ battery recycling laboratory, Rouquette and researcher Martina Petranikova demonstrated how the new method works. In the laboratory there are spent car battery cells and, in the fume cupboard, their powdered contents. It is a finely ground black powder that dissolves in a clear liquid, oxalic acid. Rouquette makes the powder and the liquid into something reminiscent of a kitchen blender. Although it is as easy as making coffee, the exact method is a remarkable and recently published scientific advance. By adjusting the temperature, concentration and time, the researchers developed a unique new recipe for using oxalic acid, an environmentally friendly substance found in plants such as rhubarb and spinach.
Reverse the order and avoid getting lost.
The water-based recycling method is called hydrometallurgy. In traditional hydrometallurgy, all the metals in an EV stack are dissolved in an inorganic acid. “Impurities” such as aluminum and copper are removed immediately. Finally, precious metals such as cobalt, nickel, manganese and lithium are extracted separately. Although the amount of residual aluminum and copper is small, many purification steps are required and each step in this process can cause loss of lithium. With the new method, the researchers reversed the order and recovered lithium and aluminum first. Thus, they can reduce the waste of precious metals needed to make new batteries.
The last part of the process, where the black mixture is filtered, is also reminiscent of the preparation of coffee. While aluminum and lithium are in liquid form, other metals remain in “solids.” The next step in the process is to separate the aluminum and lithium.
Petranikova’s research group has been researching the recycling of metals from lithium-ion batteries for many years. The group is involved in several collaborations with companies to promote the recycling of electric car batteries and is involved in important research and development projects, such as the Nybat project with Volvo Cars and Northvolt.