BMW i3 carbon fiber automobile design

How BMW drove down the cost of carbon fiber for a premium small vehicle ($50K) by manufacturing fiber in the Pacific Northwest (cheap hydroelectric power for the 2,000°C carbonization furnace). Subject of one of the LGO students' presentations in this class.

The way BMW was able to build the i3: they took carbon fiber, which is so expensive that it could only be used in the aerospace industry — at $200 a pound for a pound saved — and they started with the premium vehicle. The BMW i3 is like a $50,000 mini car. They put the construction of the fiber in the Pacific Northwest, where they have lots of hydroelectric power. To form carbon fibers, you've got to put the polymer in the furnace at 2,000 degrees centigrade. That's a tremendous electrical energy cost. So they had to move their manufacturing to where the energy was cheapest in order to get the cost down. There were all kinds of other things they did. It's a very interesting systems thing. It's one of the students' presentations in this class — one of the LGO students who happened to have been interested in it for other reasons did a wonderful presentation on how the BMW i3 took about five or six different ways to drive the cost down. But it's still a $50,000 small car, when you could buy another small car made out of steel for $15,000. You're paying three times as much for carbon fiber.

Steve didn't really introduce himself the way I was thinking. Steve Lyons works for a firm in Boston, One International Place, the high-rise, called Kleiman and Lyons. Over the last four or five years he's been teaching in this course, he has presented patent cases before the US Supreme Court on at least two occasions. So he's not really a slouch. He has actually practiced in this field, knows something about it. It's good to have Simone, who's working in the field. Don Baskin, who's not here — Don Baskin worked for 10 or 15 years figuring out how to make lightweight automobiles for Mercedes and Chrysler. It's not just fancy materials, it's not just fancy geometry, it's actually a mixture. He's got a lot of real-life examples from real automotive companies. So it's fairly specialized in automotive. We had a student do the BMW i3 a few years ago in her presentation — a great presentation. When I was talking to Don, he's got the BMW i3 in there. Anybody know what's nice about an i3? It's a $40,000 or $50,000 vehicle made out of graphite fiber. And it's an all-electric vehicle.

So we went through that. If we want to talk about materials as a percent of the total manufacturing costs, whether it's ten or twenty percent: if steel costs four hundred dollars a ton, you can actually afford to make ships and railroads out of it, but you barely can. These are the materials that are cheap enough to make ships or railroad cars. If you're willing to go to twenty percent, we do make aluminum railroad cars because they're lighter weight, and you're pulling all that weight around. Automobiles at ten percent at steel; at 20 percent you can use aluminum and plastics, although you have a hard time using some of the plastics, but we'll talk about that later. They've built the BMW i3 and i7 with graphite fiber — we can talk about how they did that. That was a student's presentation in this class, the BMW i3. He had studied this for some time — he was a BMW employee, an LGO student. He explained how they could beat this thing, but you start loading up the i3 and it's a sixty-thousand-dollar vehicle, and the i7 is a hundred-thousand-dollar vehicle. So it's like the all-aluminum Audi. The first ones that come in are on the high end of the scale.

How to afford $50/lb carbon fiber on a $2/lb-allowable automobile: (1) sell it as a $60,000 vehicle, not a $20,000 one; (2) manufacture in Washington state next to cheap hydroelectric power, because the energy to make carbon fiber (2,000 °C heat) is the dominant cost.

So there's carbon fiber, you couldn't have built this aircraft without it. We've actually gotten carbon fiber — anybody know anything about the BMW i3? How could you afford carbon fiber composites that might cost you $50 a pound fabricated, when you can only put $2 a pound into the vehicle? First of all, it's not a $20,000 vehicle, it's a $60,000 vehicle if you start pricing it out. Second, they decided to build it in the state of Washington next to hydroelectric plants, because one of the big costs of the carbon fiber is the energy to take this stuff and turn it into carbon fiber. You have to heat it up to 2,000 degrees centigrade to make the carbon fiber composites. They built it where energy was cheap. They moved to the price of cheap energy. There were a number of things they did that were very innovative on the part of BMW to get the price down.

Tom's student paper case. $40,000 small car with carbon fiber shell. Used to make the "knock-on weight savings" point: lighter shell → smaller battery → lighter still. Connects to the value-of-weight-saved hierarchy ($200/lb airframe, $2,000/lb engine, $20,000/lb turbine disk).

Tom: In fact, that was one of the students in this class — his paper — the BMW i3, which is a carbon fiber shell. That vehicle costs about $40,000. It's a small car, but the way they were able to do that — plus carbon fibers are kind of expensive these days, and they still got this two-dollar-a-pound savings — is, you actually have knock-on savings. When you went to the carbon fiber you got lighter, which means you could have a smaller battery, which makes you lighter. The knock-on from things. Not only that, he had a manufacturing course with Kerry, of course — I talked about the value of a pound of weight saved on a turbine disk is not $200 a pound like it is for the structural airframe. It's $2,000 a pound on the engine, and on the disk which spins really fast it's more like $20,000 a pound on the commercial aircraft. If you take a pound off one you can take a lot of weight off something else. Taking like 20 pounds out of the engine means lighter wings, and for the Air Force it means two thousand dollars worth of payload, extra bombs, or extra range in terms of fuel economy.