Nevertheless, the energy density of lithium ion batteries is improving and it is this that EV range depends upon. The size and weight of today’s batteries has more to do with mechanical rather than chemical elements. “Only 35% of the battery’s mass is electrically active,” Greenwood says. The rest of the weight comes from the electrical equipment and the ‘Russian doll’ packaging of components within components. “Even if we did nothing to the chemistry we could reasonably double the energy density,” he adds. “WMG has demonstrated technology with 80% better energy density than current batteries.”
Today only a tiny percentage of cars are EVs, but if the numbers rise, charging will present challenges. “Charging speed and infrastructure will matter more than range,” says Stephen Doyle, Ricardo’s head of hybrid and electrical products. Faster charging requires more powerful chargers and batteries capable of receiving that power.
Tesla’s superchargers currently charge at a maximum rate of 120kW per car, but Doyle predicts an alternative to Tesla’s network “pushing that up to 150kW”. Beyond that, ultra-fast charging at 350kW is being researched in Europe and the US, and the Ultra E consortium, including Audi, BMW and utility companies, has said it will deliver 25 350kW stations by next year.
One of the challenges is heat. “Charging at 120kW generates about 10kW of heat,” says Doyle, but 350kW generates more like 50kW, or the equivalent of 16 domestic room heaters. “Inductive ‘wireless’ charging by parking over a pad is limited to 22kW on passenger cars to meet electromagnetic compatibility standards and ensure there’s no impact on pacemakers or electrical devices like phones,” adds Doyle.
Lithium ion chemistry is likely to dominate for at least a decade, but the use of different materials should increase range. Much later, other improvements may include a move to smaller, lighter batteries filled with solid rather than liquid electrolyte.
3: The future of self-driving cars - when a car becomes a mobility service
The Sedric is the Volkswagen Group’s self-driving car of the future. The concept itself won’t make production but much of the technology will – in around 10 years’ time, says the firm. The technology could appear in all VW Group brands including Audi, Bentley, Bugatti, Seat, Skoda and includes just three controls – Go, Stop and Call – as well as advanced voice control tech that will be able to run all but the crucial systems. Volkswagen says self-driving cars will first find favour in controlled environments such as factories and car parks, then for car sharing before finally reaching private ownership.
Sedric pods could be private or public. Public pods could be identified when they arrive by colour and audio, so the visually impaired can use them.
An array of sensors includes a 360deg Light Detection And Ranging (LIDAR), camera and radar sensors. The system gives ‘triple redundancy,’ each method covering the other in case of confusion or failure.
4: The future of hydrogen cars - why they're a matter of when, not if
Hydrogen fuel cells combine hydrogen and airborne oxygen to make electricity, with only water and heat as by-products. A fuel cell electric vehicle (FCEV) is simply an EV that uses a fuel cell as its source of electricity. The fuel cell’s hydrogen supply can be replenished at a pump in about the same time as it takes to refuel a conventional car, and fuel cells could take over as the favourite power source for EVs beyond 2025.