A circular approach to the design of lightweight electric vehicles
Polymer-based composite materials and hybrid metal/composite components have long been explored to reduce weight in the automotive sector. Despite significant progress over the last two decades, their market adoption for structural elements remains limited, primarily to low-volume, high-end vehicles, with a few exceptions. Key barriers include high material and manufacturing costs, slow production rates and concerns over the reliability and robustness of these materials.
Embracing a circular approach
The EU-funded LEVIS made significant progress in these areas, advancing technology and promoting sustainability in the automotive sector. Its efforts centred on improving existing solutions, developing new ones and preparing them for seamless industrial implementation. Focus was placed on increasing the use of bio-based, recyclable and recycled materials, as well as creating new approaches for end-of-life product management. LEVIS also developed tools and methodologies to integrate eco-design practices and conducted environmental and cost life-cycle analyses. “We achieved significant advancements in sustainable materials and manufacturing processes. LEVIS developed recyclable materials and components, using bio-resourced and recycled carbon fibres, and adopting a circular-design approach to extend the service life of structural parts, while enabling efficient dismantling and material recovery,” notes José Ramón Valdés, project coordinator.
Improved methods to scaling up manufacturing
The project team used innovative manufacturing methods to produce and validate four demo parts: a suspension control arm, a battery pack, a battery housing with integrated bus bar and a cross-car beam with a steering column carrier. These parts achieved a total weight reduction of around 30 % in all cases. The demonstrator manufacturing processes were successfully scaled up, with efforts concentrated on optimising parameters for resin transfer moulding, injection moulding, press forming and pultrusion techniques. Aluminium-composite joint configurations were analysed and optimised for the internal and side beams of the battery box, as well as for the steel-composite joint linking the steering column carrier group to the cross-car beam.
Advanced algorithms to improve structural integrity and lifespan prediction
On the theoretical front, LEVIS demonstrated advanced simulation workflows to improve structural integrity and predict component lifespan. These included multi-scale models that connect processes, the structure of the materials and their properties, as well as a fatigue model that assesses this phenomenon based on a stiffness degradation based on matrix damage. Researchers advanced process simulation methodologies for thermoplastic resin transfer moulding, improving understanding of the relationships between process parameters, structural performance and material properties. Micro-mechanics models allowed calculating homogenised mechanical and thermal properties of composite materials, providing crucial input for component-level simulations. Structural health monitoring algorithms were also validated for detecting failure modes.
Benefits by the numbers
Suitable end-of-life strategies for disassembly, recycling and reuse methods in new automotive parts were deployed. On-demand dismantling technology for separating multi-material structures achieved 98 % debonding effectiveness, with thermally expanded particles enhancing efficiency and reducing energy use of separation. Optimised low-temperature pyrolysis recovery minimised material weight loss to just 3 % and retained 85 % of the tensile strength in recovered carbon fibre-reinforced plastic. The life cycle assessment showed that the impact of EVs on climate change could be reduced in most of the cases, particularly in more than 25 % for the battery pack components. The life cycle costing analysis revealed that all three demonstrations reduced costs compared to the benchmarks. Two of them achieved the project objective of a 20 % reduction. “Weight reduction studies estimated a 31 % decrease in body-in-white weight and a 5.46 % reduction in global warming potential.” emphasises Ramón Valdés. “The rate of energy consumption was improved by 5.46 %, enabling reductions of 9 kg in motor weight and 16 kg in battery cell weight, enhancing vehicle performance and energy efficiency.”
Keywords
LEVIS, electric vehicle, circular approach, lightweight, recyclable, carbon fibre-reinforced plastic
