Pulling no punches, electric cars aren’t currently suitable for everyone, even if larger examples like the Tesla Model X came with mainstream price tags. Sales reps and other at-work drivers who regularly take distances like Leeds to London and back in their daily stride are unlikely to relish currently typical recharging times of 30 minutes or more at best, while purists who crave visceral enjoyment out of driving will becry the heaviness of many EVs because of the weight of their batteries.
Swedish scientists may have identified a rather clever potential solution, though, which could make electric vehicles considerably lighter and therefore not only more agile and spacious but also able to provide longer ranges.
Carbon fibre has long been known as a remarkable but expensive material used to make racing cars and more recently normal sports cars as light as possible while still being as strong as steel or aluminium. At the relatively humble end of the model spectrum, BMW’s i3 boasts a carbon fibre-reinforced plastic (CFRP) monocoque, and the material’s price has fallen over the last few years, although disadvantages include the wasteful manufacturing process and relative challenges in recycling it.
Imagine, though, if carbon fibre could be more than just a material but could actually store energy, essentially acting as a battery electrode (conductor). Such a breakthrough could pave the way for the load-bearing external bodies of electric cars of the future to become part of the energy system, basically becoming structural batteries and therefore enabling manufacturers to ditch separate battery packs which so often weigh EVs down and eat into boot space.
This is exactly what a study led by Chalmers University of Technology in Sweden has identified. Funded by the Swedish Innovation Agency called Vinnova, along with the country’s Energy Agency and Research Council plus the Alistore European Research Institute, a multidisciplinary group of researchers led by Professor Leif Asp has ascertained for the first time that carbon fibres with small and poorly oriented crystals in their microstructures possess good electrochemical properties. Slightly reducing the stiffness of car body material means that it can operate as a structural lithium-ion battery’s electrodes.
Leif Asp is Professor of Material and Computational Mechanics at Chalmers University of Technology and provides this fascinating glimpse into what will perhaps shape the future of electric cars and other vehicles from trucks to planes:
“It will also be possible to use the carbon fibre for other purposes such as harvesting kinetic energy, for sensors or for conductors of both energy and data. If all these functions were part of a car or aircraft body, this could reduce the weight by up to 50 percent.”
Reassuringly for opponents of EVs on safety grounds, Professor Asp further explains that “the lower energy density of structural batteries would make them safer than standard batteries, especially as they would also not contain any volatile substances”, so it all sounds rather positive.
Automotive firms will have to change the way they think and operate in order to harness this potentially significant technological step, though, optimising vehicles at system level rather than in terms of individual components, so that a car’s weight, strength, stiffness and electrochemical properties are all taken into account for each model.
Equally impressive announcements have been made in the past and since fallen quiet, and although the concept of carbon fibre emulating batteries and capacitors sounds like a no-brainer, plenty of questions need addressing.
It’s likely that larger, flatter surfaces of electric cars’ bodies like bonnets, wings, doors and roofs would be used as batteries rather than their pillars, but there’s been no divulgence of what kind of driving range such technology will be capable of delivering initially and then in the future once fettled. Unless a consensus is reached across the automotive industry whereby carbon fibre is agreed on as the way forward, it’s conceivable that traditional lithium-ion battery pack technology will have progressed at such a rate within just a couple of years from now that the value in pursuing the Swedes’ technologies would be perceived as nonsensical, recharging times of circa five minutes having become the norm by that stage.
The effects of damage to body-panels that are essentially a car’s power-source is also unknown, it seeming plausible from a layperson’s perspective that such a vehicle’s driveability may be rendered reduced and perhaps even dangerous or vulnerable after even a minor prang let alone a more serious collision. Short circuits tend to lead to a build-up of heat, which could conceivably result in the risk of explosion, while scientifically naïve people may also wonder about the possibility of lightning strikes, pointing to the likelihood of the outer layer of such vehicles being made from a revolutionary material like graphene, with the carbon fibre battery layer beneath.
Scientific news like this is exciting but always has to be viewed realistically, with other potential EV adoption accelerators such as car powertrain batteries the size of SD cards also sounding promising. One thing’s for sure – the vehicular world will never be the same again.