Integrated Assessment Models, Industrial Ecology and the energy-material nexus of electric vehicle batteries

Raw materials have a significant impact on climate change mitigation. They are vital for many low carbon technologies but can contribute to high cost, environmental emissions and supply risks. Sustainable material strategies, from new technology design to governmental policies or industrial practises, are therefore increasingly recognised as important levers to support the low carbon transition. To make well-informed technical decisions, trade-offs between sustainability objectives of material strategies such as costs, emissions, material criticality, as well as technical performance need to be considered. To assess these trade-offs, different discipline-specific assessment models need to be integrated. However,
structured approaches to operationalise the integration of such models are currently missing.

Accordingly, the aim of this research is to improve the applicability of integrated modelling for low carbon technologies and sustainable material strategies.

In this thesis, a general methodological framework for Integrated Modelling of Sustainable Material Strategies (IM-SMS) was developed. The framework combines several analytical models and includes procedural steps, general mathematical formulas, a database structure, and a concrete suggestion for an open-source software implementation. The IMSMS framework was tested using the case of electric vehicle batteries. A parameterised model for lithium-ion battery design was established to assess the cost, emissions, material criticality and technical performance of different material strategies. The results show a significant trade-off between technical performance and the other objectives. Material strategies from a cost, emissions and criticality point of view reduce the technical performance by 46% compared to optimal strategies for the performance. However, technical performance as the main decision variable in battery design can lead to new material challenges.

A balance between these objectives is essential to establish sustainable material systems for electric vehicle batteries. As such, the IM-SMS framework is presented as a useful tool to support policy and industrial decisions for the low carbon transition.