Carbon composites bring many advantages for EVs, but at what cost?

The BMW i3 electric car made a bit of a splash at the Frankfurt Auto Show last week, because it is highly innovative in a number of ways. One of the headline innovations is the Carbon Fibre Reinforced Plastic (CFRP) passenger compartment – a first use of carbon composite materials in the core structure of the body shell for a mass-market production vehicle.

But it comes at a cost. Using the UK pricing as an example, the i3 starts a £29,950 ($47,807 USD, €35,810 EUR) for the base model, although it will be eligible for Government subsidies such as the £5,000 ($7,981 USD, €5,978 EUR) grant in the UK.

Even with the subsidy that will make it £7,440 ($11,876 USD, €8,896 EUR) more expensive than the entry level 1-series, and a staggering £13,081 ($20,880 USD, 15,641 EUR) more than the similarly sized BMW mini, for a car with less than a 100 mile (161km) range.

How much of that price difference is down to the composites used in the body?

It’s hard to do more than speculate with the data I have, but I’m going to attempt some un-educated guesswork: Carbon fibre costs between 20 and 80 USD/Kg depending on quality. Carbon Fibre composites are typically 4.5 lighter than steel, so to save the 250-350 Kg BMW claim their CFRP achieved: that would require around 60kg of carbon, which would be somewhere in the region of $3000 USD for the raw fibre material alone.

Plus the costs of the specialist team, additional materials and the plant they built in Germany to turn the fibres in to the CFRP parts, so double it: $6000 USD (£3,758.52 GBP, €4,494.38 EUR)

Clearly BMW are confident that this material is the future of automotive manufacturing, and not just for electric vehicles, because they have also invested Cap-ex in to the joint venture with SGL Group and built the factory to produce the fibres.

But in the case of the i3: I don’t fully understand how it equates to a consumer advantage/reason to buy, despite the quoted advantages and figures stated by BMW.

The Nissan Leaf retails in the UK from £20,990 ($41,486 USD, €31,076 EUR) including the government grant, so the difference in price between the carbon composite BMW and the more conventional Nissan: $6,321 USD (£3,960 GBP, €4,735 EUR). That’s convenient: I’ve reached the same number: approx $6,000 USD.

To summarize: the i3 costs $6000 USD more than the the Nissan Leaf, presumably because it uses innovative carbon composites (among other innovations), making it light in order to increase the range, and yet it has a slightly shorter range than the Leaf.

And it uses a charge standard for quick charging that hasn’t actually been installed yet.

It’s faster than the leaf, i’ll give it that, and it’s a BMW so will generally demand a premium, and the car reviews so far like the way it drives and feels inside. But it’s a very expensive small car however you do the sums, and that may well be the major problem for sales.

BMW have stated that the majority of i3 owners will buy them as a second car for city use. This segment is not large though, and while BMW would market their cars as exclusive, they are in fact very much mass-market and at the top of the sales charts in a number of classes.

At Frankfurt BMW stated that “We want to produce the i3 for the mass market”, but they haven’t priced it that way, and so far it would seem that they are struggling to reduce the costs of producing their composite parts enough that they are able to. I think if they could they might have packed a few more batteries in the design, thus using some of that weight saving to achieve a greater range. But to do so would further increase the cost.

There is no doubt that carbon composites offers many advantages for mass produced vehicles: Weight saving and strength being the most obvious, and eventually manufacturing processes will bring new benefits around forming of the final products – injection molded body-shells and body-shell batteries to name a couple.

But for now it is expensive, which for EVs is a bad thing: batteries and development costs are already making EVs considerably more expensive than conventional combustion cars, which I believe is the biggest single objection to purchase. Range anxiety would be far less of a problem for the majority of urban and semi-urban drivers, if the vehicles were competitively priced in the first place.

This is a long-term investment by BMW for which they should be lauded, because only by investing in this way will they be able to reduce the costs and push the market forward. But for now I fear that they have produced a car which has no immediately obvious advantages over their competitors, and is more expensive, in a market where a primary consumer objection is price. And there’s that issue with fast charging.

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