Modelling the Flow and Allocation of Materials from Battery Recycling through Production

Abstract: With the current shift towards renewable energy sources, the demand for batteries is expected to follow an exponential increase in the future, and lithium-ion batteries will be the bulk of it. In order to reduce carbon dioxide emissions from battery production and to secure future availability of critical metals, more batteries will need to be recycled. To incentivize this, the European Union will impose regulations on recycling efficiencies as well as recycled content in produced batteries. The purpose of this study was twofold. Firstly, it was to construct a model in Microsoft Excel which could follow the flow of materials from recycling through production and keep track of an inventory which could be allocated to customers as needed. Moreover, the model had to be able to calculate values such as recycled content in produced battery cells and take into account losses from production etc. Secondly, this thesis aimed to use the model to determine how many old cells would have to be recycled in order to produce a modern cell with a certain percentage of recycled content, as well as to determine which recycled active cathode metals there might be surpluses and shortages of. This was done as a case study at the company Northvolt AB, by gathering data from literature, interviews, and site visits. The model was then built iteratively, based on a material flow analysis approach. Finally, the model was used in a methodical manner to test the conversion rates and to determine how big the shortages and surpluses of materials would be. This thesis argues that there is no truly relevant literature on building a material flow and allocation model such as the one required here. However, using the method described above, it was possible nonetheless to construct the novel model. The model consists of several sheets with distinct functions and is scalable while also adaptable to other companies and industries. Among other things, it keeps track of inventory levels with a scalable time axle and helps the user set values to reach target recycled weight percentages. The model can also be used to perform the analyses required for the second half of the purpose of this thesis. The key outcome from that, was that recycling old batteries and producing new ones is far from a 1:1 process and that higher requirements on recycling efficiencies could greatly improve that. Moreover, the active cathode metals which would require the largest amounts of batteries to be recycled in order to produce new cells with recycled content at certain levels, were identified as bottlenecks. When using the required recycling efficiencies from the European Union in 2025 and 2030, the bottleneck metals were lithium and nickel if the new batteries were to contain 100 % recycled active cathode metals. However, if the recycled content should be in line with European Union regulations, the bottlenecks would be cobalt and nickel instead. This could shift the demand for virgin active cathode metals in favor of cobalt and nickel.