Protean Electric raises $70 million for in-wheel drive systems, will ramp up China production


Protean Electric, a developer of in-wheel electric drive systems, has generated $70 million in funding from an equity financing round. The company will use the new money to ramp up production in China of its PD18 product line.

Protean is setting up a manufacturing site in Tianjin, China, and plans to form a manufacturing joint venture with Chinese auto parts manufacturer Zhejiang VIE to produce other in-wheel motor products.

According to Protean, its in-wheel motors, which are suitable for both passenger and commercial vehicles, can boost an electrified vehicle’s energy efficiency by up to 15 percent compared to a centralized motor.


“This funding accelerates the adoption of our innovative technology in the booming electric vehicle market in China,” says Protean CEO KY Chan.

“VIE’s strong China customer base, its broad range of chassis products, and its manufacturing prowess are highly complementary to Protean’s technology leadership,” said Leal Jiang Chen, President of VIE Group.

“Protean has developed a next-generation power train with greater potential than anything I have seen in my 30 years in the automotive industry” says Frank Chao Lyu, Chairman of Tianjin THSG.


Source: Protean Electric

  • Jim Fox

    what? no cv joints, no drive shafts, no gearbox? WTF?

  • brian_gilbert

    I would like a clearer figure than ‘up to’ 15%. I use a spreadsheet to compute the financial return on adoption of a Completely Driverless Zone. I cannot do much with an ‘up to’ figure. My cirrent figure is 2p a mile for electricity for a 4 seater passenger vehicle based on the Nissan Leaf in the UK. What would it be if the Leaf had in-wheel motors?

  • DHZ

    The ZEV Electric company has used this type of in wheel motor now 8 years. zero moving parts. Just the bearings turning in the wheels. No motor has ever had service or broken in 8 years. Even on delivery fleets. So big advantage for maintenance.
    As to the energy use, 15% should be no problem. The ZEV just ran in the Vetter Challenge, an efficiency competition against electric motorcycles with 30% more battery capacity. Running at the same speeds, over the same 135 mile course, the ZEV with the hub motors beat all of the bikes that used non hub motors, even the special built streamliners as far as efficiency of watts per mile consumed. On motorcycles, the hub motor is worth never less than 15% over all others and as much as 60% against some competitors in terms of range efficiency, watts consumed per mile. You see this especially when the range of the ZEV Electric is slightly better than bikes with 60% more battery capacity when driving at the same speeds.
    I would expect Protean to have no problem to achieve 15%. The more the driving is done in the low speed, stop and go mode, the more the advantage. The hub motor have all of their torque at 0-70 rpm where most electrics with a drivetrain require 4,000 rpm. In a 700 lb motorcycle/rider combination, the ZEV hub motors are using 32-35 watts per mile from the battery in the under 45 mph driving, 60 watts per mile at 55 mph.

    • brian_gilbert

      Thanks, very useful.

    • Barry L Alexander

      No moving parts? How does it turn the wheel?

      • DHZ

        The outside of the hub motor turns, not the shaft. So the shaft is bolted immovable solid in the wheel spindle if a car, or in a swingarm for a motorcycle. On the shaft are the windings. The outside of the motor is actually the rim of the wheel on many motorcycle hub motors or the normal car wheel bolts to the outside of the motor. The magnets are on the outside of the motor. Then the magnetic forces, acting with the permanent magnets make the motor turn. No gears, clutch, drive belts, chains, nothing. Part of what makes these things work so well is the diameter. In electric motors if you double the diameter you get about a 4X increase in torque. So the larger the diameter the better. Putting the magnets on the outside is also to get the OD at the air gap up. In wheels you have the room to run large OD motors. Which also then leaves lots of room in the body/chassis for more battery.

      • Electric Bill

        Barry– a “hub” or “wheel” motor like in this article is an example of an “inside-out” motor.

        Electric motors consist of two sets of magnets–either electromagnet or permanent magnets– which interact with each other to create the turning motion we use to power the wheels. One of the magnets— either the ones on the outside, or the ones on the inside–have to be electromagnets made of copper coils that can be switched on and off very quickly as the car travels down the road.

        Most motors have a “stator” magnet arranged around the outside. The “stator” does not move. Inside the stator is the shaft that holds the other set of magnets, which turn because they are pushing and pulling against the stator’s magnetic field.

        A “hub” motor (or “wheel” motor) is an example of electric motor that is “inside-out”. An inside-out motor has a central shaft that does not turn, with magnets which are also not turning… the parts that turn on an inside-out motor are on the OUTSIDE, which can be rigidly attached to the wheel and tire. That way an electric car can have no moving parts except for the wheels— the magnetic parts that make the wheels move are part of the wheel itself.

        “Gadge”, below, mentions unsprung weight. What he is talking about is that a car wheel usually has the weight of the tire, wheel, brake caliber and the brake drum or brake rotor. The heavier all those parts are, the harder it is to control the car as it rides over bumps and potholes. The problem also becomes more difficult as speed increases. For this reason, race cars need the very lightest wheels and tires possible, so are not a good candidate for hub motors, which can be quite a bit heavier. But if a car, spends all of its time in a congested city with slow traffic and mostly smooth, even streets, a hub motor can have advantages.

        But if someone could get very clever and invent a hub motor that is as light as a conventional wheel with nothing but a brake caliber and brake disk, it could be the next big thing in EVs. That would be difficult, but maybe someone as clever as Elon Musk could do it.

  • Dennis Worley

    Great ….learning from E bikes finally !

  • Gadge

    Is the unsprung weight of 4 wheel-motors an issue?

    • Dennis Worley

      Yes ….the heavier the motor the more the problem, IMO the solution is carbon fiber leaf springs between rim and rotor.See U Tube bike videos! Also on heavy vehicles a tandem lay out would give air damping from tires.
      What do you engineers think?