Cranfield research is helping to develop a new generation of battery technologies needed for a future of sustainable electric transport.
The work on lithium-sulfur batteries is part of a major new £29 million UK research programme into energy storage funded by The Faraday Institution.
A lighter battery option for vehicles
Lithium-sulfur batteries have a number of potential advantages over existing lithium-ion battery technology. Availability of lithium-sulfur batteries will mean a lighter option for vehicles: important for electrification of short-haul aircraft and light goods vehicles in particular. Today’s typical lithium-ion batteries produce around 250 watt hours per kg of mass, compared with what is expected to be 400-600 watt hours per kg from lithium-sulfur. At this stage, researchers believe lithium-sulfur may also be a cheaper technology for industry and consumers.
The constituent elements of lithium-sulfur batteries mean less dependence on scarce minerals — the types of ‘conflict materials’ which often can only be sourced from countries where there are serious questions over human rights and employment conditions.
Potential huge value to a spectrum of industries
Research lead Dr Daniel Auger, Reader in Electrification, Automation and Control in Cranfield University's Advanced Vehicle Engineering Centre, said: “With the ongoing surge towards electrification, there’s a need for a range of battery technologies and options for development. While still playing an important role, lithium-ion batteries have begun to reach their limit in terms of performance improvements. Lithium-sulfur is one of the emerging alternatives that is closest to being commercially available.
“Lithium-sulfur batteries are going to be of real value, for example, for aircraft, where fuel load is everything; for light goods vehicles, allowing them to have more capacity and not tip over into the 7.5 tonne category. But also for passenger vehicles, the lighter battery means less energy is needed for acceleration and to overcome rolling resistance. A whole spectrum of industries is going to be interested in the qualities of the new batteries.”
Cranfield to develop sophisticated battery management system
The LiSTAR research project – led by University College London and also involving the universities of Birmingham, Cambridge, Coventry, Imperial College London, Nottingham, Oxford, Southampton, Surrey – aims to maximise the potential of the lithium-sulfur technology, including issues around energy density and lifetime of cells, exploring the use of the best performing materials.
The Cranfield team led by Daniel Auger is looking at developing a sophisticated battery management system: providing accurate information on charge levels, and insights into how operation of the vehicle impacts on battery life. The work will also involve running simulations to model the behaviour of the battery in particular vehicle types.
“This work is important because understanding what is happening inside a lithium-sulfur battery is harder than with lithium-ion,” explained Dr Auger. “There is just the one stage of electrochemical processes in lithium-ion, but four in lithium-sulfur. The charge is also very ‘flat’, meaning there are regions of the battery where it is very difficult to ‘see’ the charge. We have to look for different kinds of indicators of what’s happening.”
Phase two of the LiSTAR project begins in April 2023, building on existing university research on the technology, with outputs expected within two years.
Programme to invest in most promising battery research initiatives
The Faraday Institution programme includes six battery research projects designed to lead to commercial products and ventures: such as extending battery life, improving safety, as well as recycling and reuse; and new battery technologies like lithium-sulfur and ‘solid-state’ (using solid electrodes and electrolyte rather than a liquid).
Professor Pam Thomas, CEO, Faraday Institution, commented: “The Faraday Institution is committed to identifying and investing in the most promising and impactful battery research initiatives. This project refocusing is an important part of that process, and allows us to direct even more effort towards those areas of research that offer the maximum potential of delivering societal, environmental, and commercial impact.”
Business and Trade Minister Nusrat Ghani said: “Growing the battery industry is vital to positioning the UK as the best location in the world to manufacture electric vehicles.
“This funding will help businesses become more innovative and productive, helping to create more skilled, high-wage jobs across the UK, future-proofing our economy and supporting our ambition towards a cleaner, greener future.”