Aluminum or Steel body for Model 3

I am going to bet most of the panels will be some sort of plastic while the frame will be some sort of aluminium alloy.

Aluminum will cost way too much to keep the car at 35k. You cant have a costly battery pack and aluminum and a nicely teched up car for that small of a price. Steel/plastic parts body with fabric seats for a base model for sure.

Questions we're not really able to answer, but which Tesla likely is figuring out right now: How much of the cost of an Audi A4 (comparable aluminum-intensive benchmark for the Model 3 starting at $35,900) made up of the drivetrain vs. the aluminum-intensive body? How much battery capacity is saved to hit target range by using aluminum, and is that cheaper than using (and tooling up for) steel? Does going with aluminum for the 3 help them get better pricing for aluminum on the battery packs, S and X - increasing margins there?

Feh. My 6 year old pickup has an AL hood. I think this "AL is too expensive" stuff is overblown. If Chevy can do it, Tesla can.

Maybe the chassis/unibody won't be AL, but the panels could be.

I've owned a couple of Saturns way back when. The plastic body panels worked well.

Frankly, I think they could be plastic/steel/aluminum, take your pick.

And one of the nice things about the Saturn was that it didn't easily dent or ding because if it got hit the panel would just pop back out. You might get a scrape or a crack in the paint or the topcoat, but that was the worst of it. I think if the 3 had plastic body panels, I'd be okay with that. It would certainly make for easier repairs by places other than expensive Tesla-approved body shops. But the underlying frame would need to be slightly beefed up because steel or aluminum panels are part of what provides impact protection -- plastic not so much.

One more data point. Ford F150. As of 2015, aluminum body, steel ladder frame. Starting MSRP, $26615.

Eventual annual volume is similar.

tga said:

I've owned a couple of Saturns way back when. The plastic body panels worked well.

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Wasn't one of the problems with plastic panels the amount of thermal expansion? Large gaps had to be left between panels. I imagine this wouldn't be ideal for drag coefficient or looks.

If Ford can make a decent profit on an aluminum F150, I am thinking that Tesla can do the same on the Model 3.

Tesla already knows how to make the panels out of aluminum and they have spent a lot of time perfecting welding and bonding with aluminum.

A lighter car means that the battery pack can be smaller than with a heavier car and the batteries are still going to a major cost component. I say go with what you know.

I think the added cost of aluminum is overstated but then what do I know.
My guess is aluminum battery pack with steel body which is a reasonable compromise between weight and cost.
Would also make insurers happy since it would reduce repair costs which would should help keep insurance premiums lower.

Another case for some steel from Tesla VP of engineering Chris Porritt:
“I expect there will be very little carry-over. We’ve got to be cost-effective. We can’t use aluminium for all the components.”

http://gas2.org/2014/07/01/tesla-model-e-will-built-mostly-steel-priced-realistically/

Bangor Bob said:

Questions we're not really able to answer, but which Tesla likely is figuring out right now: How much of the cost of an Audi A4 (comparable aluminum-intensive benchmark for the Model 3 starting at $35,900) made up of the drivetrain vs. the aluminum-intensive body? How much battery capacity is saved to hit target range by using aluminum, and is that cheaper than using (and tooling up for) steel? Does going with aluminum for the 3 help them get better pricing for aluminum on the battery packs, S and X - increasing margins there?

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A4 is aluminum intensive, but still far less aluminum than the Model S for example. Most of it is steel, esp. the chassis:
http://www.repairerdrivennews.com/2...-264-6-pounds-lighter-includes-more-aluminum/

I suspect the Model 3 will be similar.

Several people at Tesla have said the Model 3 will make much more use of steel. I have seen comments that it will have little to no aluminum.

There are differences with working steel and aluminum. Steel is more durable and doesn't develop cracks that can propagate like aluminum. Pure aluminum is much softer than steel, but aircraft aluminum alloys can be harder, though much much more expensive. I don't think anybody is using much aircraft aluminum in cars. Purer alloys of aluminum are much more corrosion resistant than steel, which is an advantage. Of course steel, being harder doesn't get damaged as easily and is usually cheaper to repair.

I don't think there are major differences painting the two metals.

Shocker: model s has some steel body parts.
At most there will be more of them in model E where weight differential is overweigthed by price differential.

There are many articles out there on how the Model 3 will make much more use of steel.

Here's one: http://www.teslarati.com/tuned-third-generation-tesla-model-e-will-utilize-steel-construction/

stopcrazypp said:

A4 is aluminum intensive, but still far less aluminum than the Model S for example. Most of it is steel, esp. the chassis:
http://www.repairerdrivennews.com/2...-264-6-pounds-lighter-includes-more-aluminum/

I suspect the Model 3 will be similar.

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Bangor Bob said:

Questions we're not really able to answer, but which Tesla likely is figuring out right now: How much of the cost of an Audi A4 (comparable aluminum-intensive benchmark for the Model 3 starting at $35,900) made up of the drivetrain vs. the aluminum-intensive body? How much battery capacity is saved to hit target range by using aluminum, and is that cheaper than using (and tooling up for) steel? Does going with aluminum for the 3 help them get better pricing for aluminum on the battery packs, S and X - increasing margins there?

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Not much Aluminum on the new Audi A4 ... only the red and blue areas highlighted below.

Audi USA vaguely described the eighth-generation 2013 Audi A4 as a “galvanized steel unibody construction with aluminum hood”

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I wonder if Tesla are talking to, or at least considering, Alcoa in regards to their new alloy tech they announced around a year ago. I think Ford are looking to use them very soon.

I'd rather they go with Ultra High Strength steel for whole cage, high strength for the front, then mild steel for the rest.

Volvo XC90

MacroP said:

I wonder if Tesla are talking to, or at least considering, Alcoa in regards to their new alloy tech they announced around a year ago. I think Ford are looking to use them very soon.

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I've wondered that, too. The new aluminum is something like 40% lighter, easier to stamp, and stronger. What I don't know is where it is cost versus today's aluminum.

My impression is that the weight saving advantages of aluminum wrt battery size aren't all that large. At highway speeds drag is the main limit on range. In stop-and-go traffic weight is an issue for acceleration energy but some of that is (usually) recovered by regen braking, unlike in an ICE car. And stop and go traffic tends to be at lower speeds, meaning lower drag. I don't buy the idea that aluminum will have a significant impact on the battery size needed for a given range.

One advantage of reducing the weight in the Model S with aluminum is improving drag race type acceleration and performance. With the Model 3 cost savings should be more important than 0-60 times.