EU may ban carbon fibre
Discussion
My guess is that they'll reach some sort of compromise where the manufacturers are required to make sure any CFRP components are easy to separate for recycling in a controlled environment. And possibly also pushing manufacturers to pay for that dedicated recycling.
If that resulted in the death of small pieces of non-structural CFRP bling, I can't say it would be the end of the world.
Fully banning structural CFRP would be quite contentious given the potential it has to make cars lighter and hence more efficient.
If that resulted in the death of small pieces of non-structural CFRP bling, I can't say it would be the end of the world.
Fully banning structural CFRP would be quite contentious given the potential it has to make cars lighter and hence more efficient.
Edited by kambites on Tuesday 15th April 07:45
That would upset a lot of OEMs. How will they charge 20k extra for their 'special' model that has carbon fibre mirror caps and an extra 5hp ? 
I do kind of get the idea though. The stuff is hard to recycle and the dust etc that's released when doing so isn't good. I wonder if we'll see something a bit more sustainable make it's way onto the market, Hemp reinforced polymer?
I do kind of get the idea though. The stuff is hard to recycle and the dust etc that's released when doing so isn't good. I wonder if we'll see something a bit more sustainable make it's way onto the market, Hemp reinforced polymer?
Crudeoink said:
I do kind of get the idea though. The stuff is hard to recycle and the dust etc that's released when doing so isn't good. I wonder if we'll see something a bit more sustainable make it's way onto the market, Hemp reinforced polymer?
In the majority of the places it's used in road cars, GRP with a pretty sticker on top would be just as good. 
durbster said:
Are you posting from a rollercoaster?
He's Billy Corgan and he's doing a skydive from space.https://youtu.be/Kz45sv9BDB4?si=gKXOlfB3irEwQDYH
The end-of-life thing by the EU. Recyclability seems to be a thing now. We had the court case and fines as manufacturers colluded on not using the amount of "recyclability" in their marketing for their products: https://www.pistonheads.com/gassing/topic.asp?h=0&...
The ELV will also pick up EV batteries.
Will we see manufacturers build in the forecast recycling costs into the price of new cars? Or rather, will we see cars built in the EU have the cost of recycling built into their purchase price?
The ELV will also pick up EV batteries.
Will we see manufacturers build in the forecast recycling costs into the price of new cars? Or rather, will we see cars built in the EU have the cost of recycling built into their purchase price?
GT9 said:
One of the key enabling materials for hydrogen cars...
They can't use some other material?Crudeoink said:
That would upset a lot of OEMs. How will they charge 20k extra for their 'special' model that has carbon fibre mirror caps and an extra 5hp ?
I do kind of get the idea though. The stuff is hard to recycle and the dust etc that's released when doing so isn't good. I wonder if we'll see something a bit more sustainable make it's way onto the market, Hemp reinforced polymer?
Isn't it the polymer, rather than the carbon fibre, that's the problem?I do kind of get the idea though. The stuff is hard to recycle and the dust etc that's released when doing so isn't good. I wonder if we'll see something a bit more sustainable make it's way onto the market, Hemp reinforced polymer?
Don't know what size particulates you get when cracking, splitting or crushing carbon fibre, but it's quite likely to prove to be a chronic lung irritant in the same way that asbestos fibres are.
Quite possibly a cancer risk if inhaled as well.
I guess we will start to see pleural plaques in carbon fibre exposed individuals in 40 years or so if that's going to be a problem.
Quite possibly a cancer risk if inhaled as well.
I guess we will start to see pleural plaques in carbon fibre exposed individuals in 40 years or so if that's going to be a problem.
Edited by OIC on Tuesday 15th April 14:02
Super Sonic said:
Isn't it the polymer, rather than the carbon fibre, that's the problem?
Sort of, yes. The sort of "Carbon Fibre" that the majority of readers will recognise is the thermoset resin based composites as used extensively in motorsport and aerospace. Being a thermoset means it is created by a permanent chemical reaction (think of araldite / epoxy resin when you mix the two liquids together it goes hard). To separate the carbon fibres from the resin for recycling is therefore pretty impractical other than by burning off the resin at high temperature, so instead the carbon fibre components are shredded to become a filler material for making new composites with new resin (think 'forged' carbon, a great excuse to get rid of waste and charge the customer for a premium material!). I believe the EU concern raised is as a result of the fibres (and fibre dust) that get released when a CF component is shredded for recycling.
There are alternatives to thermoset composites that may offer slightly less hazardous recycling options, using thermoplastic resins. These can be reshaped by heating up to an appropriate softening temperature, and (in theory at least) have the resin melted away from the carbon fibre filler. Much work is ongoing in aerospace to develop TP composites for both recycling and production efficiency reasons, so perhaps this will trickle down to automotive a bit faster with EU legislation like this.
rodericb said:
They can't use some other material?
Not for the fuel tanks, no not really.The very high tensile strength combined with low density allows for the fuel tanks to operate at 700 bar to store sufficient hydrogen to give the car a viable range.
And even at that pressure the extremely low volumetric energy density of hydrogen, combined with the relatively high wall thickness of the tanks and their domed cylindrical form, results in an effective volumetric energy density about an order of magnitude lower than petrol.
i.e. Instead of a 50 litre tank, you need 500 litres to store the same energy.
Fuel cell cars are a bit more energy efficient tank-to-wheel than petrol or diesel, but it still means a large portion of the car is given over to fuel storage, and due the extremely explosive nature of the fuel, tank rupture is to be avoided at all costs.
Hence the tanks are typically positioned close to the mid-planes of the car to minimise the chance of impact damage to the tanks.
Having such a large volume of fuel and with thick walls, these tanks weigh in at nearly 100 kg just to store 5 kg of hydrogen.
Most cars have at least 2 if not 3 separate tanks to fit it all in.
Homogeneous metals would significantly increase the mass of the tanks due to their higher density AND are unlikely to be able to operate at 700 bar as they don't offer the same tensile strength, so the range will be much lower.
I doubt a viable hydrogen passenger car can be built without the use of carbon fibre composite tanks to store gaseous hydrogen fuel.
There are some metal matrix composites with ceramic fibres, but I'm not sure if the cost, physical properties or strength-to-mass ratio is workable for this application.
The long-term failure mechanism for the carbon fibre composite tanks is usually low cycle fatigue from filling and emptying the tanks where the internal pressure cycles between 700 bar and whatever pressure they get down to before refilling them.
So whatever material is used, it will also have to survive that cyclic duty.
Alternatives for storing hydrogen have been tried, including cryogenic storage of liquid hydrogen as well as 'powerpaste' where the hydrogen is combined with magnesium to form a metal hydride that can be stored at ambient pressure.
Both have severe limitations though.
Liquid hydrogen boils off (a full tank in the space of about a week) and must be vented to atmosphere of re-liquified, so only really works in applications where the cost of the cryogenic production (-253C) can be accommodated and the tanks are emptied (usefully) almost straight away after filling to minimise fuel loss, i.e. motorsport, aviation, etc.
The metal hydride paste requires the magnesium to be recycled on an ongoing basis, and requires lots of it, something like 50 kg to store 5 kg of hydrogen. There have been no efforts to seriously consider this for automotive use, due to the highly complex chain of supplying fresh canisters of paste to the car and then returning waste canisters of the magnesium to some centralised facility for conversion back to fresh canisters.
In any case, production cost and energy efficiency of both the paste and liquid hydrogen options don't compare well to pressurised gaseous hydrogen, itself now proving to be a very expensive and commercially non-viable fuel for passenger cars.
To be honest I could have just typed that last half sentence and that's all you really need to know about hydrogen cars....
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