New eco-friendly batteries for tomorrow's electric vehicles
Innovations in battery design are increasing the acceptability of electric vehicles among consumers. An EU-funded project is developing a more powerful, cheaper, and environmentally friendly lithium-ion battery to meet the expectations of drivers - and boost Europe's competitiveness in the market.
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The next generation of lithium-ion (Li-ion) batteries will make electric vehicles (EVs) more attractive to consumers. This could spark an accelerated take-up of EVs. To retain a competitive advantage, European Li-ion battery manufacturers need to be at the cutting edge of battery research and development, with scope for big improvements in the performance, cost, safety, recyclability, lifetime and weigh of Li-ion batteries.
The EU-funded SPICY project aims to develop a more powerful, cheaper, safer, lighter, long-lasting eco-friendly Li-ion battery, which will meet the needs of EV drivers. The project is addressing production processes and the whole value chain for the materials used to make Li-ion batteries.
SPICY, which ends in July 2018, is well on its way to achieving its overall aim of reducing battery production costs by 20% through substituting rare and expensive materials with cheaper ones. Thanks to intelligent cell design, the project is also on track to increase battery performance by 20%, due to improved energy density and a higher voltage, says project manager Willy Porcher, of the Alternative Energies and Atomic Energy Commission (CEA), France.
The project also seeks to improve the safety and the recyclability of components by using less harmful materials, and increasing lifetime. Better cell performance can also lead to valuable reductions in battery weight.
These advantages are a step towards a higher acceptance of electro-mobility, which will most likely be empowered by these Li-ion battery systems, says Porcher.
The key project innovations are the development of novel materials for electrodes anodes and cathodes including silicon and polyanionic phosphates, the use of a more eco-friendly solvent during the manufacturing process, and new and optimised cell architectures and packaging built using eco-design concepts.
For use as a negative electrode, the project team is studying new mixtures of graphite and silicon, the latter produced through new synthesis process methods that improve stability. For the positive electrode, improvements are being made in the energy density performance of lithium iron phosphate (LiFePO4), a safe and durable material for which low energy density has been a limitation.
LiFexMn1-xPO4 is the material developed in the project as it has many advantages, like the fact it can exchange lithium ions very fast, allowing high power, and the phosphate stabilises the structure which is why this material is very safe, says Porcher. It is really ideal for plug-in hybrid electric vehicles, which require power capability for fast charge on slopes or when using the brakes.
The project has already achieved its specific energy target of 160Wh/kg for plug-in hybrid electric vehicles.
SPICY is also investigating the replacement of a toxic solvent in the battery cell manufacturing thanks to a new water-soluble polymer, which reduces production costs and facilitates an easier recycling process. SPICYs development of the material could enable the recovery of more than 50 % of the battery, a significant improvement compared to the present situation.
The project is testing new cell architectures and packaging on three pilot lines at project partners based in Grenoble, Munich and San Sebastian. The project team has developed a new protective composite packaging, with an integrated battery management system for intelligent cell monitoring.
SPICY is assessing battery lifetime and durability, for example, by using abusive thermal and charging regimes. Modelling tools are also being used to understand and improve cell design, and to confirm that cell design optimisation can result in an energy saving of 5-10 % compared to conventional cells.
Boosting the European battery industry
The projects life-cycle assessment and cost analysis addressed the best options for manufacturing the next generation of Li-ion batteries for EVs in Europe. By optimising cost and mainstreaming eco-design principles, the multidisciplinary collaboration involving industrial, academic and research centre partners aims to help provide a strong industrial base for European battery producers to exploit global markets.