Aluminum is used in the battery casings of most swappable batteries and in the battery pack enclosures of electric cars (EVs). It is also used in the conductors, cooling systems, crash structures, housing trays, and terminals of batteries. The vast majority of EVs are powered by lithium-ion batteries. Each of these batteries consists of “a densely packed collection of hundreds, even thousands, of slightly mushy lithium-ion electrochemical cells, usually shaped like cylinders or pouches”.
🌱 How are EV batteries currently recycled?
The aluminum and lithium in EV batteries is currently recycled through an aqueous-based method called hydrometallurgy. In the traditional method, all metals found in an EV battery cell are dissolved together within an inorganic acid. Next, the so-called “impurities” – such as aluminum and copper – are removed and valuable metals – such as cobalt, lithium, and manganese – are recovered. While the quantity of “impurities” is relatively small, their removal requires numerous purification steps. Notably, in each step, lithium may be lost.
🌱 Is there a more efficient recycling method?
A group of researchers at Chalmers University of Technology in Sweden have recently developed a new recycling method for aluminum and lithium from EV batteries. The method is more efficient, as it can recover 100% of the aluminum and 98% of the lithium found in an EV battery. The loss of other valuable raw materials – such as cobalt, manganese, and nickel – is also reduced. According to the researchers, they are the first to find “exactly the right conditions for separating this much lithium using oxalic acid, whilst also removing all the aluminum”. They say the process can be scaled up and it “does not require the use of expensive or harmful chemicals”.
🌱 How does the new recycling method work?
In the new method, the lithium and aluminum are recovered first. This is a reversal of the order used in current hydrometallurgy. In the new process, the pulverized contents of EV batteries are dissolved in oxalic acid, which is a transparent organic liquid. (Oxalic acid can be found in plants, such as spinach and rhubarb. It is a more environmentally friendly ingredient than the inorganic acid typically used in hydrometallurgy.) This mixture is then placed into a machine that mixes it rigorously and causes the aluminum and lithium in the batteries to fully dissolve in the oxalic acid. The other metals are left behind as solids. In the final step of the process, the different metals are separated and recovered. This is possible due to their different individual properties. The recycled aluminum and lithium won through this process can be used to make new batteries.
Read more about the use of aluminum and lithium in batteries here: