"Super light electric bikes could soon be a reality..." ??

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Big breakthrough for ’massless’ energy storage

Mon, Mar 22, 2021 07:00 CET


Researchers from Chalmers University of Technology have produced a structural battery that performs ten times better than all previous versions. It contains carbon fibre that serves simultaneously as an electrode, conductor, and load-bearing material. Their latest research breakthrough paves the way for essentially ’massless’ energy storage in vehicles and other technology.

The batteries in today's electric cars constitute a large part of the vehicles' weight, without fulfilling any load-bearing function. A structural battery, on the other hand, is one that works as both a power source and as part of the structure – for example, in a car body. This is termed ‘massless’ energy storage, because in essence the battery’s weight vanishes when it becomes part of the load-bearing structure. Calculations show that this type of multifunctional battery could greatly reduce the weight of an electric vehicle.

The development of structural batteries at Chalmers University of Technology has proceeded through many years of research, including previous discoveries involving certain types of carbon fibre. In addition to being stiff and strong, they also have a good ability to store electrical energy chemically. This work was named by Physics World as one of 2018’s ten biggest scientific breakthroughs.

The first attempt to make a structural battery was made as early as 2007, but it has so far proven difficult to manufacture batteries with both good electrical and mechanical properties.

But now the development has taken a real step forward, with researchers from Chalmers, in collaboration with KTH Royal Institute of Technology in Stockholm, presenting a structural battery with properties that far exceed anything yet seen, in terms of electrical energy storage, stiffness and strength. Its multifunctional performance is ten times higher than previous structural battery prototypes.

The battery has an energy density of 24 Wh/kg, meaning approximately 20 percent capacity compared to comparable lithium-ion batteries currently available. But since the weight of the vehicles can be greatly reduced, less energy will be required to drive an electric car, for example, and lower energy density also results in increased safety. And with a stiffness of 25 GPa, the structural battery can really compete with many other commonly used construction materials.

“Previous attempts to make structural batteries have resulted in cells with either good mechanical properties, or good electrical properties. But here, using carbon fibre, we have succeeded in designing a structural battery with both competitive energy storage capacity and rigidity,” explains Leif Asp, Professor at Chalmers and leader of the project.

Super light electric bikes and consumer electronics could soon be a reality
The new battery has a negative electrode made of carbon fibre, and a positive electrode made of a lithium iron phosphate-coated aluminium foil. They are separated by a fibreglass fabric, in an electrolyte matrix. Despite their success in creating a structural battery ten times better than all previous ones, the researchers did not choose the materials to try and break records – rather, they wanted to investigate and understand the effects of material architecture and separator thickness.

Now, a new project, financed by the Swedish National Space Agency, is underway, where the performance of the structural battery will be increased yet further. The aluminium foil will be replaced with carbon fibre as a load-bearing material in the positive electrode, providing both increased stiffness and energy density. The fibreglass separator will be replaced with an ultra-thin variant, which will give a much greater effect – as well as faster charging cycles. The new project is expected to be completed within two years.

Leif Asp, who is leading this project too, estimates that such a battery could reach an energy density of 75 Wh/kg and a stiffness of 75 GPa. This would make the battery about as strong as aluminium, but with a comparatively much lower weight.

“The next generation structural battery has fantastic potential. If you look at consumer technology, it could be quite possible within a few years to manufacture smartphones, laptops or electric bicycles that weigh half as much as today and are much more compact”, says Leif Asp.

And in the longer term, it is absolutely conceivable that electric cars, electric planes and satellites will be designed with and powered by structural batteries.

“We are really only limited by our imaginations here. We have received a lot of attention from many different types of companies in connection with the publication of our scientific articles in the field. There is understandably a great amount of interest in these lightweight, multifunctional materials,” says Leif Asp.

Read the article in the scientific journal Advanced Energy & Sustainability Research:
A Structural Battery and its Multifunctional Performance





Watch a Youtube video here on: Structural battery with record performance

More about: The research on structural batteries
The structural battery uses carbon fibre as a negative electrode, and a lithium iron phosphate-coated aluminium foil as the positive electrode. The carbon fibre acts as a host for the lithium and thus stores the energy. Since the carbon fibre also conducts electrons, the need for copper and silver conductors is also avoided – reducing the weight even further. Both the carbon fibre and the aluminium foil contribute to the mechanical properties of the structural battery. The two electrode materials are kept separated by a fibreglass fabric in a structural electrolyte matrix. The task of the electrolyte is to transport the lithium ions between the two electrodes of the battery, but also to transfer mechanical loads between carbon fibres and other parts.

The project is run in collaboration between Chalmers University of Technology and KTH Royal Institute of Technology, Sweden's two largest technical universities. The battery electrolyte has been developed at KTH. The project involves researchers from five different disciplines: material mechanics, materials engineering, lightweight structures, applied electrochemistry and fibre and polymer technology. Funding has come from the European Commission's research program Clean Sky II, as well as the US Airforce.

For more information contact:
Leif Asp, Professor at the Department of Industrial and Materials Sciences, Chalmers University of Technology, +46 31-772 15 43, leif.asp@chalmers.se



________________

Chalmers University of Technology in Gothenburg, Sweden, conducts research and education in technology and natural sciences at a high international level. The university has 3100 employees and 10,000 students, and offers education in engineering, science, shipping and architecture.

With scientific excellence as a basis, Chalmers promotes knowledge and technical solutions for a sustainable world. Through global commitment and entrepreneurship, we foster an innovative spirit, in close collaboration with wider society.The EU’s biggest research initiative – the Graphene Flagship – is coordinated by Chalmers. We are also leading the development of a Swedish quantum computer.

Big breakthrough for ’massless’ energy storage

[] Researchers from Chalmers University of Technology have produced a structural battery that

news.cision.com

 

[Deleted member 33385]

Carbon does continue to surprise... we're carbon based too, but most people have about 100W capacity.

 

[flecc]

This section kills it:

"The battery has an energy density of 24 Wh/kg, meaning approximately 20 percent capacity compared to comparable lithium-ion batteries currently available. But since the weight of the vehicles can be greatly reduced, less energy will be required to drive an electric car. "

The battery on my e-car is about 21% of the car's weight, fairly typical. Even if all of that could be saved, losing 80% of the capacity would leave it with a fraction of it's current range and performance, completely unacceptable and not even viable in today's traffic. It would be comparable to the milk float battery powered era.

Even if they tripled the capacity it would barely reach the standards of my three year old e-car, and they are being rapidly improved. For example, its latest version has 61% more capacity.
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[Deleted member 33385]

This section kills it:

"The battery has an energy density of 24 Wh/kg, meaning approximately 20 percent capacity compared to comparable lithium-ion batteries currently available. But since the weight of the vehicles can be greatly reduced, less energy will be required to drive an electric car. "

The battery on my e-car is about 21% of the car's weight, fairly typical. Even if all of that could be saved, losing 80% of the capacity would leave it with a fraction of it's current range and performance, completely unacceptable and not even viable in today's traffic. It would be comparable to the milk float battery powered era.

Even if they tripled the capacity it would barely reach the standards of my three year old e-car, and they are being rapidly improved. For example, its latest version has 61% more capacity.
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Maybe their elecric cars of the future have 3ft thick body panels? Cars like that would be single passenger only, or one up front and one at the back. Capacity tends to increase when any new kind of battery is developed further. Let's hope it develops by a lot!

Have you installed an engine noise generating machine, or is your electric car a silent assassin?

 

[flecc]

Maybe their elecric cars of the future have 3ft thick body panels? Cars like that would be single passenger only, or one up front and one at the back. Capacity tends to increase when any new kind of battery is developed further. Let's hope it develops by a lot!

Like over 99.9% of all battery breakthrough announcements, this one will never happen. To even catch up with this years models it would have to have at least four times the capacity, which isn't remotely on the cards.

Have you installed an engine noise generating machine, or is your electric car a silent assassin?

It has built in sound generator, but since it's not this years model and in the UK, it can uniquely be switched off. That's only in the UK since we have a law which forbids the use of a vehicle horn during night hours. The problem is that our vehicle horns are in law "an audible means of warning of approach". So is an e-car artificial noise, so to comply with the law they have to be switched off at night between about 11.30 pm and 7.15 am. In all other countries e-car warning noise is permanently wired in.

I always drive with mine off since they are useless anyway. It only operates up to 19 mph since at any higher speeds the car reaches a pedestrian before they've heard it and reacted. Once off at 20 mph it doesn't come on again until speed drops below 13 mph, so useless most of the time anyway. I just take care to avoid pedestrians and avoid startling them, as any good driver should. And in any case the hum of the air-con outside the car is as loud as the artificial noise and the latter doesn't sound like any car I've ever heard.

A warning sound is useless in law anyway since as two crown court judges said recently when sending a driver and a cyclist to prison for 18 months each. It's their responsibility in law to stop in time and a sound warning doesn't excuse failing to do that.

Our law on e-car noise is being rewritten from this year to permit it to be compulsorily full time on new models.
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[Deleted member 33385]

A warning sound is useless in law anyway since as two crown court judges said recently when sending a driver and a cyclist to prison for 18 months each. I

Do you have a link to the cyclist case? 18 months seems pretty harsh. What were the circumstances? Was he riding an ebike?

Like over 99.9% of all battery breakthrough announcements, this one will never happen. To even catch up with this years models it would have to have at least four times the capacity, which isn't remotely on the cards.

Announcements like these don't usually herald technology which will feature in anything you would be able to buy for about ten years, if at all. They might discover that some materials are stronger and have less capacity, and others hold more charge but are less strong, and construct vehicles accordingly using both.

And in any case the hum of the air-con outside the car is as loud as the artificial noise and the latter doesn't sound like any car I've ever heard.

In these days of highly configurable gizmos, I'm surprised you don't have options like "Sherman Tank", "Morris Minor" or "Cruise Missile". Must say I don't tend to hear Nissan Leafs very much... I only recently got a Zefal rear view mirror, which I'll try out later today.

 

[Deleted member 33385]

A warning sound is useless in law anyway since as two crown court judges said recently when sending a driver and a cyclist to prison for 18 months each. It's their responsibility in law to stop in time and a sound warning doesn't excuse failing to do that.

This might be the cyclist - not an ebike. 18mph isn't fast, easy to achieve on an ebike:

Cyclist Charlie Alliston jailed for 18 months over death of pedestrian

Alliston jailed over death of Kim Briggs, who sustained ‘catastrophic’ head injuries in east London collision last year

www.theguardian.com

 

[Deleted member 33385]

Once off at 20 mph it doesn't come on again until speed drops below 13 mph, so useless most of the time anyway. I

You could replace it with ice cream van tunes, those are the most road noticeable noises. But might just be me.

 

[flecc]

You could replace it with ice cream van tunes, those are the most road noticeable noises. But might just be me.

Not for me, I prefer silence. You can see the illogicality of added e-car noise when it's no use at or over 20 mph since it's not heard and reacted to by a pedestrian before being hit.

Since it can only be useful under 20mph, why doesn't the law for bicycles insist they emit a continuous warning noise since they are silent, that is their common speed range and they sometimes kill pedestrians too?

Our legislators once again not thinking things through before acting.
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[sjpt]

You can see the illogicality of added e-car noise when it's no use at or over 20 mph since it's not heard and reacted to by a pedestrian before being hit.

I think I prefer silence too. However, together with a speed limit of 20mph wherever there is a significant number of pedestrians (which would be a good thing in its own right) it would not be illogical to require cars up to 20mph to issue a warning.

 

[flecc]

I think I prefer silence too. However, together with a speed limit of 20mph wherever there is a significant number of pedestrians (which would be a good thing in its own right) it would not be illogical to require cars up to 20mph to issue a warning.

It would be illogical if it didn't apply to other 20 mph silent vehicles that can and do kill, like bicycles.

A very good thing about e-cars is that they will forcibly educate people not to cross roads stupidly using only their ears instead of their eyes. Once a high proportion of cars and vans are e-powered a warning sound won't be needed any more with everyone using their eyes.
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[sjpt]

It would be illogical if it didn't apply to other 20 mph silent vehicles that can and do kill, like bicycles.

A very good thing about e-cars is that they will forcibly educate people not to cross roads stupidly using only their ears instead of their eyes. Once a high proportion of cars and vans are e-powered a warning sound won't be needed any more with everyone using their eyes.
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I'm not sure RNIB will be with you on that one.

 

[Amoto65]

It would be illogical if it didn't apply to other 20 mph silent vehicles that can and do kill, like bicycles.

Not really a comparison is it, The amount of cars that kill people far outnumbers the amount of bikes, And when they all become electric that will be the norm.

 

[flecc]

And when they all become electric that will be the norm.

And then a warning sound won't be needed since pedestrians will had got used to using their eyes for a change instead of just stepping off the kerb.

That said, in over three years with an e-car always in silent mode I haven't had one moment of a problem with it having no engine noise. That's hardly surprisimg since the higher end Rolls Royces have been quite silent for decades.

It's a greatly exaggerated problem, the tyres and my air con make a noise and the sound generator noise is so quiet that with windows open I still had to step out of the car and walk to the front to even hear it to see if it actually worked.

Here lots of owners leave it turned off as I do and in the USA many take out the fuse to have silence.
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[Deleted member 33385]

the higher end Rolls Royces have been quite silent for decades.

Most of that silence is achieved by using hundreds of pounds of sound dampening material.

Since it can only be useful under 20mph, why doesn't the law for bicycles insist they emit a continuous warning noise since they are silent, that is their common speed range and they sometimes kill pedestrians too?

Bikes are far less likely to kill people or animals.

That said, in over three years with an e-car always in silent mode I haven't had one moment of a problem with it having no engine noise. That's hardly surprisimg since the higher end Rolls Royces have been quite silent for decades.

It's a greatly exaggerated problem, the tyres and my air con make a noise and the sound generator noise is so quiet that with windows open I still had to step out of the car and walk to the front to even hear it to see if it actually worked.

Three years are no measure. Most drivers have gone their whole lives without knocking over a pedestrian. The silence of your electric is not as dangerous at the moment, because you're often grouped on the road with petrol cars. There might be some sort of mod you can install, which emulates a Rolls Royce Silver Ghost.

An alternative mod is an extremely sharp scythe-like bumper, to leave fewer witnesses...

While disguised as a pedestrian, I've always found the sudden discovery of a silent Nissan Leaf zooming by a bit shocking.

And then a warning sound won't be needed since pedestrians will had got used to using their eyes for a change instead of just stepping off the kerb.

Do electric cars kill more hedgehogs? Like squashed hedgehogs, statistics are a bit thin on the ground. An ultrasonic emitter installed under your car might help alert hedgehogs - it wards off other rodents.

 

[mike killay]

Not for me, I prefer silence. You can see the illogicality of added e-car noise when it's no use at or over 20 mph since it's not heard and reacted to by a pedestrian before being hit.

Since it can only be useful under 20mph, why doesn't the law for bicycles insist they emit a continuous warning noise since they are silent, that is their common speed range and they sometimes kill pedestrians too?

Our legislators once again not thinking things through before acting.
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I once saw an 1890's advert for bicycle 'Jingle bells', the same sort that you sometimes find on reins for a toddler.
Attaching them to a bike would give out a continuous jingle.

 

[Deleted member 33385]

I once saw an 1890's advert for bicycle 'Jingle bells', the same sort that you sometimes find on reins for a toddler.
Attaching them to a bike would give out a continuous jingle.

But then there would be the expectation of presents as you pass by, and when those are not forthcoming, there would be anger and disappointment... you'd have to explain it's because they had been bad little boys and girls, and there would be tears and tantrums. It'd cause as big a drama, as using the ice cream van noise.

Jungle Bells might be better suited to the task. Infinitely annoying:

 

[Amoto65]

Here lots of owners leave it turned off as I do and in the USA many take out the fuse to have silence.

Which is pretty irresponsible as it is there for a reason as is the speed cutoff on E-bikes. As a pedestrian or cyclist you need to be able to hear an oncoming vehicle especially if you are pulling out at a blind junction or one with limited visibility.

 

[flecc]

Which is pretty irresponsible as it is there for a reason as is the speed cutoff on E-bikes. As a pedestrian or cyclist you need to be able to hear an oncoming vehicle especially if you are pulling out at a blind junction or one with limited visibility.

That's complete nonsense and irresponsible of anyone if only using ears to do that.

The junction from my road out to the T junction road at the end is made blind much of the time due to a bus stand on the immediate left with buses paused for several minutes. I woudn't dream of relying on hearing a vehicle for exiting, apart from anything else, I probably couldn't when inside my closed car. Whether walking, riding or driving I just edge out far enough to be able to start seeing if it's clear before advancing further, though when walking I usually just cross at a safer spot.

As I've told you, these e-car sounds have been found to be useless by huge numbers of drivers, as much as anything because none of them sound remotely like a motor vehicle so pedestrians and cyclists take no notice of them. We are the ones driving them so do know far more on the subject than armchair experts who've read something.

There's a big problem in deciding what sort of sound is needed and no consensus as yet. Imitating the low frequency spectrum of current vehicles isn't practical or possible in free air, and probably pointless when most of those vehicles are going to disappear from the roads anyway. An agreed standard sound worldwide is needed which all will recognise as a vehicle, but with research into this being fragmented across car companies and bodies like the RRL we are getting nowhere on it at present while models and numbers are being released at an ever increasing pace.

Anyway, from this year on new models in the UK will all have a sound locked in to satisfy the critics, even though they won't add anything to safety like my one when it's on.
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[Amoto65]

Anyway, from this year on new models in the UK will all have a sound locked in to satisfy the critics, even though they won't add anything to safety like my one when it's on.

So why do you turn it off if it adds to safety? Seems a bit foolish.