Modular 'skateboard' chassis concept given REE-newed lease of life

It's an idea that will not die – a modular automotive platform with low-emissions energy storage packed in a sandwiched floor and decentralised powertrain systems.

General Motors was one of the pioneers in its field, with the Hy-Wire design study from 2002, but that idea didn't seem to go anywhere... until now.

REE, a company operating out of Tel Aviv, has revisited GM's 'skateboard' approach, but with a few differences. The fuel-cell power generation of the GM concept has been ditched in favour of an all-electric power storage system, and the single electric motor of Hy-Wire has given way to down-scaled powertrain systems operating independently at each wheel – in either a two- or all-wheel drive configuration. This type of architecture also allows four-wheel steering as a further possibility.

But it's actually the different powertrain setup that truly distinguishes the REE concept from Hy-Wire. The powertrain systems are not based on either the single-motor layout of the GM concept, nor the 'motor-in-hub' systems that have been promoted in the past as an alternative to single- or dual-motor powertrain systems.

In this way, according to REE CEO and founder Daniel Barel, the company avoids the problems associated with that type of system – unsprung weight, potential for damage from the road surface and the conflict between gearing and power delivery.

"Everything in our system is connected through a very unique – and patented, of course – gearbox, or drivetrain, that can allow for vertical movements while maintaining peak performance," Barel told online technology publisher New Atlas, formerly gizmag.com.

Barel was not very open about the means by which torque is transferred to the wheels from the motor, other than spruiking one particular benefit of the company's patented system.

"If you think about a car today, you might think about a half-shaft, which is usually how you transfer torque. Those usually lose about eight per cent of their torque capability where they reach the top and bottom of the suspension stroke and create the largest angles. Our technology does not suffer from those scenarios, it remains just as efficient throughout the suspension travel."

REE claims its transmission system multiplies the torque available from the small electric motors without detriment to the motors' energy efficiency. The motors produce more torque at higher revs, which would make them unsuitable for an automotive application without the transmission lowering the final drive ratio.

The holistic chassis concept has been in development for the past six years, but Barel says that REE is beginning to see the fruits of its labour, with the 'disruptive' architecture gaining interest from Mitsubishi and other car companies. According to Barel, the platform can support applications ranging in size from a golf cart up to a 10-tonne truck – and the ability of the powertrain system to work within long-travel suspension parameters makes it suitable for off-road duty too.

There were four key aims in development of the architecture. It had to be upgradeable, it had to offer efficient packaging, it had to exploit advanced low-consumption energy systems and it had to be light in weight. Packaging efficiency is aided by the platform's reliance on electric connections between the driver and the drive systems, steering and braking.

"There's an economic driver there too," Barel said. "The single biggest expenditure for an OEM [original equipment manufacturer]... is the platform, developing and validating it.

"It costs billions, it takes years, and each OEM has between two and six platforms at any given moment, and two or three in development. We went in and said 'what if you might need only one? That might be worth something.'"

If the concept ends up in production, it will begin reaching customers in one form or another around 2023. Barel believes that low-speed autonomous vehicles will be first to adopt the technology, followed by commercial delivery vehicles.