By on October 24, 2013

That CFRP cowl panel is really storing electricity.

BMW is using carbon fiber composite unibodies for the electric i3 and i8 models to reduce their weight, thereby increasing their range. Now, Volvo is using carbon fiber in a novel way for EVs. Using carbon fiber it has developed a composite material that acts as a capacitor, storing electrical energy, so theoretically body panels and structural components could act as battery equivalents. Unlike conventional batteries, which add weight to a vehicle, the carbon fiber capacitive body panels wouldn’t just power the vehicles but also reduce weight.

To demonstrate the technology, Volvo replaced the the trunk lid, door panels, cowl, and hood of an S80 with the new composite. The panels are made of multiple layers of carbon fiber, insulated from each other with layers of fiberglass. The fiberglass acts as a dielectric with the layers of carbon fiber performing the tasks of the anode and cathode in a conventional capacitor.


Volvo estimates that replacing an EV’s entire battery pack with capacitive panels would reduce total vehicle weight by 15%.  It would also help in packaging. One criticism of the Chevy Volt is that its large centrally mounted battery pack turns a five passenger platform into a four passenger car. If the car’s structure is the power source, space formerly used for batteries can be put to better use.


There are possibilities for conventional vehicles as well, with the potential to replace the heavy 12 volt starter battery with just a few capacitive carbon fiber panels.

There are possible drawbacks, including cost and safety. Carbon fiber is expensive to work with so panels would be costly to make and to replace. Also, in the event of a collision that damages the panels’ electrical safety could be a concern.

As usual, there was no world on when, or if, this technology will ever see its way to a production vehicle.

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20 Comments on “Volvo Capacitive Carbon Fiber Panels Could Replace Batteries, Save Weight In EVs & Conventional Cars...”

  • avatar

    So how many Wh or kWh does one kg of panel store? I mean is it significant?

    And if someone leans on my car, or if there is a dent, does it mean my “battery” has a short?

    More details need to be shown, this sounds good, but is it really?

    and is the capacity similar to super-caps?

  • avatar

    While a good concept this may proove problematic when implemented on production cars, plus with the average life of car batteries this means your Volvo will require a new BODY after 10 years.

    • 0 avatar

      It’s a capacitor not a battery.

      “Physically, batteries rely on the chemical compositions of metals and the acids in between to determine the capacity, resistance, voltage, and recharge-ability. This limits the possible voltages and the like to predetermined values.

      Capacitors (in general) do not rely on these chemical processes and metal compositions, but rather the electric fields between metal plates.”

  • avatar

    My first concern is safety for first responders. We already know they have to be careful when cutting into EVs so that they don’t short out a high-energy electric line. Also, it seems an accident could easily short these capacitors and start a fire, but fiberglass may do a decent enough job of fire retardation to prevent against that.

    Overall, it’s an impressive idea and I hope it works.

  • avatar

    Volvo thinking “outside the box” – irony (because styling)

    But I’m also a bit skeptical – in production, carbon fibre in widespread use could also mean higher repair costs for relatively-minor accidents, and insuring costs…

    • 0 avatar

      Todays cars are already expensive to repair in minor accidents, its good revenue for them and it gets people out of used cars hoping to buy a new one of the same make “Such and such saved me life”.

    • 0 avatar

      “higher repair costs”

      On the other hand: faster, safer, better acceleration, braking, cornering, better gas mileage and it doesn’t rust.

      • 0 avatar

        Geez I never said that used old beaters were better, just that there was at least one upside.

        They don’t have to compromise this way though, modern cars could be cheaper to fix in fender benders while still being as safer, faster, blablablah.

        And last I checked Mazda never got rust under control quite yet.

      • 0 avatar

        And don’t forget all the collision avoidance technology.

  • avatar

    “Also, in the event of a collision that damages the panels’ electrical safety could be a concern.”

    You’re worried for the safety [belonging to] the panels? I’d be more worried about driver / medical personnel safety.

  • avatar
    SCE to AUX

    Just because something can be done doesn’t mean it should be done.

    While novel, this will never be cheaper than producing dedicated batteries – and EV cost is a big deal.

    By the way, the Volt’s lack of a 5th seat isn’t really due to the battery. It’s due to the packaging problem presented by having a 4-cylinder engine, exhaust system, fuel tank, etc. My Leaf has more battery than a Volt, yet it has 5 seats.

  • avatar

    Wow, sounds like a science project right now, but you never know what it could turn into.

  • avatar

    So hack car writers who love to write things like, “This car looks like it’s sizzling with pent-up energy!” will finally be factual.

  • avatar

    I suppose when when these cars get hit the panels will explode? Shorting capacitors is not like shorting batteries.

  • avatar

    Engineering porn with a possible application, but not for passenger cars.

    I hope its more reliable than the power seats on my V70 :)

  • avatar

    “BMW is using carbon fiber composite unibodies for the electric i3 and i8 models to reduce their weight, thereby increasing their range. ”

    The Chinese invented gunpowder before the Europeans. Volvo seems to be taking this technology where it needs to go???

  • avatar

    I will try to remember this the next time I pee on an electric car

  • avatar

    As to the safety aspect. Carbon fiber is way stronger than steel so it stands a vastly better chance of keeping it’s integrity in a collision but… it does not bend, it cracks and shatters and that would not be good.
    I guess they could use it internally as part of the strengthening framework they use so much now (those super thick A pillars).
    Exciting stuff anyhoo!

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