The future of lightweight batteries for cars
The automotive industry devotes a lot of effort to improve existing technology for the manufacture of more robust and energy-efficient cars. Reduction of the overall weight of cars has been identified as an aspect that needs improvement to minimise brake and tyre wear and lower fuel consumption and carbon dioxide emissions. Apart from the body, the engine and the transmission system, weight can be cut down in current lead-acid batteries. The MEMLAB(opens in new window) (Melt spun and sintered metal fibre networks for lead-acid battery advancement) project was launched to replace part of the lead with lightweight materials. The ultimate objective was to achieve a greater than 50 % reduction in the overall weight of lead-acid batteries, thereby increasing their power-to-weight significantly. Lead-acid batteries would then be a viable choice for hybrid electric vehicles that currently rely on expensive lithium-ion and nickel-metal hydride batteries. To this end, the MEMLAB team developed lightweight electrodes using state-of-the-art fibre production technology. Lightweight titanium as well as aluminium fibres were created from recycled scrap. Next, fibres were sintered to form electrode plates with high surface area. A broad variety of coating technologies including electroplating and sol-gel deposition were explored to form a conductive layer over titanium fibres to ensure current flow and protect the electrode. Researchers finally adopted a multi-layer approach because lead cannot be plated to titanium directly. The performance of the new electrodes and their suitability for use in lead-acid batteries was assessed. Promising results opened the way for small businesses participating in the MEMLAB consortium to commercialise the new battery electrodes for use in existing as well as new hybrid vehicles. Around 75 million lead-acid batteries are manufactured in Europe each year. Replacing standard lead-acid batteries with the new lightweight batteries will help to reduce the quantity of lead used and limit fuel consumption and pollutant emissions from road vehicles.
