A review of physical processes used in the safe recycling of lithium ion batteries

A review of separating methods used in domestic and electric vehicle lithium ion battery recycling is presented, focusing on physical processes which are commonly utilized prior to further chemical processing and purification steps. The four processes of stabilization, disassembly, separation and binder negation are reviewed and the strengths and weaknesses in current research identified. The main limitation with current recycling methods is the comminution step, which mixes, sometimes intimately, the materials from different cell components. This mixed waste stream requires further physical separation, and produces cross contamination in the different material streams. Effective separation of battery components, which produces enhanced purity of waste streams is essential to providing a cost-effective recycling process for direct or “closed loop” recycling. Improvements in the separation process are possible if the materials are separated prior to comminution, to prevent contamination of the different materials streams. In addition to purity of waste streams, one area mostly neglected in the literature is the health and safety implications and hazards associated with the chemicals contained within the cells. Little information is known about the chemical reactions which may occur during the physical separation processes and this has been identified as an area which needs substantially more investigation.