Combining dynamic material flow analysis and life cycle assessment to evaluate environmental benefits of recycling – A case study for direct and hydrometallurgical closed-loop recycling of electric vehicle battery systems

•Combined LCA and MFA of hydro. and direct recycling routes for a closed-loop battery value from OEM's perspective.•Savings potential of GHG emissions compared to virgin material production for recycling routes and two NMC cathode.•Analysis of admixture ratios of direct recycled cathode active material and choice of allocation method over time.•Obligatory allocation rules of EoL processes for reliable and realizable LCAs are needed to ensure correct accounting.•Technological investigation of admixture ratios for all kinds of recycling processes needed. We conduct a life cycle assessment (LCA) for two recycling processes, a hydrometallurgical and a direct recycling route. Both show ecological benefits compared to production with virgin material (between 2.76–4.55 kg CO2e/ kg battery for NMC111 and NMC811 less greenhouse gas emissions). In contrast to previous works, we combine the LCA results with a dynamic material flow model. This allows the evaluation of the influence on ecological benefits of admixture limits for directly recycled cathode material in a closed-loop recycling system over a time in which the newly produced battery systems and the amount of end-of-life traction batteries grows. We show that for such a closed-loop recycling system, the choice of different allocation methods, namely cut-off or avoided burden approach, may lead to significantly varying results of up to 85% in ecological benefits. We further conclude that combining production with both recycling routes can achieve the lowest greenhouse gas emissions for our closed-loop scenarios.