“F1 plays a part with our new hybrid solution. The efficiency we achieve there is huge," he explains. "In the past we were limited to 28-30 per cent efficiency with combustion engines, but with our current hybrid F1 drivetrain we are dealing in the 40 per cent range."
Weber predicts a future where all vehicles will be electrified, but there won't be a 'one size fits all' solution: “Even in lane one, we will see mild hybrids using belt-driven starter-generators or crankshaft integrated starter-generators. In lane two we will have the premium plug-in hybrids and by 2017 we will launch 10 plug-in hybrids. The third lane will be zero-emissions vehicles powered by batteries or fuel cells.
“By 2020, we expect the energy density of battery technology to have doubled and the cost halved,” he continues. “Without any other changes being made, the range of the B-Class Electric Drive could increase to 185 or 250 miles.”
Beyond that, Weber believes there’s more to come with new battery chemistry: “Lithium sulphur will be the next step after lithium ion, followed perhaps by lithium air. Lithium sulphur is comparable to lithium ion but lithium air will be a completely different world.”
With lithium ion batteries, the oxygen needed for the chemical reaction which generates electricity is stored internally. Lithium air batteries ‘borrow’ airborne oxygen from the air and then release it again when the battery is recharged. As a result, they theoretically have a large energy storage capacity – some sources estimate it could be close to that of petrol.
Mercedes-Benz B-class Electric Drive prototype first drive
Looking ahead further still, Weber believes the hydrogen fuel cell is still a strong contender: “With a fuel cell car you can fill up with hydrogen in three minutes but even our fastest chargers take half an hour to charge a battery, so 20 to 30 minutes will probably remain the limit.”
However, Harald Kroger, vice president of electronics and e-drive for Mercedes, thinks the limited range of an electric vehicle is an overstated problem: “These questions often evaporate if you use an EV on a daily basis. A lot of customers realise their regular driving is covered by a 95-mile range.”
Kroger concedes that on-street parking is a problem if drivers are not guaranteed a charging point at work or when shopping but under-street wireless inductive charging is technically possible. Mercedes recently demonstrated a system comprising a pad which can be placed on a driveway or in a garage and plugged into a household wall socket. The rapidly cycling electromagnetic field in the pad induces a current in an electrical coil pack on board the car to generate electricity and charge the battery.
The system is being developed in collaboration with BMW and the same system is capable of charging either brand’s cars. “The cost should be similar to that of an electric door opener,” says Kroger. The system is technically ready but a date for its introduction has yet to be set.
The technology could also make kerbside charging more practical. “My belief is that if electric charging gets into every household owning an electric BMW or Mercedes, then a technical standard could be established. If other manufacturers join that standard it may be possible to put the technology under the road as well, but that’s a little further away," says Kroger.
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