In partnership with Audi. How far does electric car technology go? Developing ever-efficient batteries with longer ranges and great power is within an engineer’s reach. As lithium-ion technology keeps evolving and charging networks keep extending, electric cars are becoming equipped to be as reliable and powerful as their traditional counterparts.
For many looking to take up electric driving, a battery’s range is often a decisive factor. Technology has already delivered solutions – but there’s always room for improvement. While engineers improve lithium-ion cells, and energy providers expand electric charging networks, there are ways to get us on the path to fully electric driving.
Few drivers tackle more than 40km on a daily basis. But weekends, holidays or unplanned occasions sometimes call for longer journeys. An electric car’s battery is well equipped to withstand the needs of quotidian use, and engineered to last well beyond the average necessities, when it can return to its owner’s garage for an unhurried overnight charge. But in the case of longer drives, as charging infrastructure progressively spreads through our streets and motorways, are there any technologies that can help supplement an electric car’s autonomy – and give peace of mind to a driver, however extensive an electric battery’s range?
Most of the batteries inside electric cars are very similar – and have been built to a comparable structure for years: they consist of lithium-ion rechargeable cells. But technological advancements have improved on this principle, delivering models with increasing efficiency and longer range. Most batteries are already able to ferry a car through almost 300km – a range that far exceeds needs as well as expectations. Yet engineers are already looking to push that limit.
“For the customer, range is the most important thing at the moment,” explains Michael Bayer from the department of development concepts energy systems at Audi, who has long worked on the development of the company’s batteries. “It depends how much you push the throttle at the end – but the intention for the future is to be in the direction of 500km. That’s our big aim.” For many drivers it may only be an issue of reassurance – yet longer ranges for batteries are a fundamental factor to help the mainstream spread of electric vehicles. At the same time, a battery that can ensure long range is often bulky and heavy, and unnecessarily slows down performance and power. Other factors must be considered to help guarantee faith in electric cars.
A battery’s energy density is a decisive issue to solve the problems of balancing battery weight and range – and an area where technological improvement is already sharp. “Only some years ago, one couldn’t imagine that the energy density of lithium-ion cells would be rising as fast as they did – it’s nearly doubled since 2013,” says Bayer. This means the same amount of energy can be stored in less space – allowing for the battery to take up less room (and weight) inside a car – or, in parallel terms, for more energy to be stored inside the same space. Ensuring that a car’s battery can be charged in less time is the responsibility of the battery technicians. As is coming up with solutions that make sure energy generated by the movement of the car isn’t wasted: “We call it recuperation,” explains Bayer. “Some kinetic energy coming from braking should come back to the battery: we gain as much energy as possible from the system.”
Inside the engines of electric cars, big steps towards the future are already being taken. But where the external charging infrastructure is still catching up with them, there are other solutions that can accompany us on the road to the future. Plug-in hybrids, like derivates of the Audi Q7 and A3 model series, are already available and combine a combustion engine with a battery. No matter how capillary the charging network, any driver should feel confident in the knowledge that their car – partially or completely battery-powered – can carry them anywhere, with no less pleasure in being behind the wheel than what they’d expect.
As head of the Faraday Institution Multi-Scale Modelling Project led by Imperial College, London’s most respected science university, Greg Offer is often asked to forecast what tomorrow holds for the automotive industry. Here he explains to us how understanding the future is less about predicting – and more about making our own choices.
Q In recent years, what have been the most striking evolutions in battery technology?
A What has changed most rapidly in the last few years is cost. Over the last five years the price of an electric car battery has come down by almost 66 per cent, which, needless to say, is a significant decrease.
Back in 2010, most of the reports were saying that the cost of a battery for an electric car that would give a consumer the same performance they expected from combustion engines would converge around 2035 – decades in the future. Thankfully, they got it staggeringly wrong, and we haven’t had to wait that long: in some market segments, electric vehicles already make more economic sense. That’s why in the last few years everybody started getting excited and started looking into it: we can’t predict the future, but we can predetermine it through our actions.
Q What other shifts in technology can we expect over the next few years?
A Lithium-ion batteries were identified as good enough years and years ago. Since then the technology has been getting better and better, but the rate of improvement is pretty consistent: between six and nine per cent per annum for both cost and energy density. That rate is going to deliver cheaper, more energy-dense batteries with longer ranges, but I don’t believe there are going to be any big-step changes.
Q How do you think the car will fit into the future of mobility?
A I very much see the car surviving, but in a very different form: in that of an automated vehicle. Autonomous vehicles skew the economics massively towards electric too.