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Vertically aligned carbon nanotubes triple the density of lithium batteries

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Re: Vertically aligned carbon nanotubes triple the density of lithium batteries

#121

Post by audunw »

0xffff2 wrote: post #60
rocqua wrote: post #6

IF this is true, it would be a massive breakthrough. Truly monumental. Hence, I am skeptical. But otherwise, this would be a massive thing. a 2x capacity per weight advantage of batteries? Without an increase in space? That comes down to doubling the range of EVs, and making electric planes and rockets a lot more viable. A 3x capacity per space advantage means roughly a 3x improvement in your phone and laptop battery…

A 3x increase in density does approximately nothing to make electric airliners more viable. We need more like a 100x increase before we see an electric 737 or A320.

100x increase? Is that based on calculation based on the energy density of fuel vs batteries alone? Because there's a lot of efficiencies to be gained if you make a battery electric plane from scratch. And are you considering only a fully fuelled plane? Because many routes will only use a small fraction of the potential fuel capacity.

Look at the Maxwell X-57 for instance. If you don't have fuel in the wings, and you can use small electric take-off propellers on the wings, you can make the wing much thinner, which reduces drag.

You can potentially fly higher with electric planes, since you no longer have to think about air densitys impact on engine efficiency.

The main challenge with electric airplanes is not really the batteries. You could probably make viable short-haul planes with todays technology. The problem is you're basically starting from scratch, as a plane optimised for electric engines is most likely vastly different from a 737 airframe. It'll take decades to design and optimize radically new airframes.

We might never see planes crossing the pacific ocean with batteries only, but that doesn't mean electric planes aren't viable. By some calculations you can do 500-1000km routes with todays battery tech already, and there's a shitload of those. Maybe you'll have to fly 2-3 smaller planes rather than one huge one to cover the same route, but that can be a good thing. You could use smaller and more local airports. Electric planes are much more quiet after all. Operating costs with electric planes are way lower, so it might not be more expensive either.

With a 3x+ capacity you can start talking about covering most of the routes within a continent. So what if you can't do transcontinental? I think we can make enough biofuel to cover that if most other flights are electric (and/or hydrogen)

Re: Vertically aligned carbon nanotubes triple the density of lithium batteries

#122

Post by gpanders »

Animats wrote: post #108

Bad headline. This increases power density, not energy density of lithium batteries, by decreasing internal resistance. That potentially increases charging speed. They claim by 10x. Car charging stations are going to need megawatt chargers if this works. They talk some about the possibility of future silicon batteries using this technology.

Wrong. From the article:

> Also, because there's gaps in that ultra-lightweight nanotube scaffolding and less extraneous binder and additive materials, a battery containing a given amount of active material can become much, much lighter and more compact. Energy density, both by weight and by volume, stands to jump by factors of 2-3.

Re: Vertically aligned carbon nanotubes triple the density of lithium batteries

#123

Post by monadic2 »

0xffff2 wrote: post #58
pbhjpbhj wrote: post #35

Earlier quoted context omitted.

>Or, more likely, a slight improvement in your phone and much thinner phones. On laptops, we might see the return of more ports. // Please, no. I don't understand the utility of making something so expensive be so fragile and hard to hold. My phone is 5mm thick, that's already too thin for me. Does anyone want thinner phones or is it just a marketing thing?

The thinner the phone, the thicker the case I can put on it with the same total thickness. It's incredibly rare to see a case-less phone in the wild these days.

I don't use a case. If it were meant to be used with a case it would come built in. Iphones could easily double in thickness without making it harder to slip into a (male) pocket.

Re: Vertically aligned carbon nanotubes triple the density of lithium batteries

#124

Post by aaronblohowiak »

gpanders wrote: post #122
Animats wrote: post #108

Bad headline. This increases power density, not energy density of lithium batteries, by decreasing internal resistance. That potentially increases charging speed. They claim by 10x. Car charging stations are going to need megawatt chargers if this works. They talk some about the possibility of future silicon batteries using this technology.

Wrong. From the article: > Also, because there's gaps in that ultra-lightweight nanotube scaffolding and less extraneous binder and additive materials, a battery containing a given amount of active material can become much, much lighter and more compact. Energy density, both by weight and by volume, stands to jump by factors of 2-3.

There are both power and energy density increases!

Re: Vertically aligned carbon nanotubes triple the density of lithium batteries

#125

Post by ginko »

bitdotdash wrote: post #118
bfieidhbrjr wrote: post #105

Earlier quoted context omitted.

> if you can build batteries with the energy density of gasoline Actually significantly worse than that. A plane gets lighter the longer it flies, especially at takeoff when everything is at max thrust. A battery becomes more and more dead weight the longer you fly.

I wonder if this could be solved for with detachable take-off booster. Gets you up in the air, then returns to the airport.

Couldn't you just start with a cable that detaches and is pulled back to the landing strip?

Re: Vertically aligned carbon nanotubes triple the density of lithium batteries

#126

Post by Robotbeat »

0xffff2 wrote: post #57
DennisP wrote: post #34

Earlier quoted context omitted.

Electric airplanes need significantly better energy density.

"significantly" sells it short. Electric airliners need a couple orders of magnitude of improvement to even come close to viability.

No they don’t. 400Wh/kg is sufficient when combined with structural efficiency and aerodynamic improvements. Over 1000 mile range should easily be feasible there in a new, clean sheet design incorporating best of everything and a 400Wh/kg battery.

Re: Vertically aligned carbon nanotubes triple the density of lithium batteries

#127

Post by TT3351 »

Teckla wrote: post #94
rocqua wrote: post #6

IF this is true, it would be a massive breakthrough. Truly monumental. Hence, I am skeptical. But otherwise, this would be a massive thing. a 2x capacity per weight advantage of batteries? Without an increase in space? That comes down to doubling the range of EVs, and making electric planes and rockets a lot more viable. A 3x capacity per space advantage means roughly a 3x improvement in your phone and laptop battery…

I would like to see phones and batteries decoupled; i.e., phones without batteries. Most people use phone cases anyway; put the battery in the phone case. Replace the case as desired.

Most Android phones used to have swappable batteries. Too convenient and not thin enough, I guess.

Re: Vertically aligned carbon nanotubes triple the density of lithium batteries

#128

Post by cestith »

pritovido wrote: post #117
seanc wrote: post #79

Earlier quoted context omitted.

I heard somewhere that in Holland every bicycle + lock weighs 5kg. If you have a cheap 5kg bike no one wants it and you don't have to lock it. If you have an expensive 1.5kg bike you need a lock that weighs 3.5kg to protect it.

In tour de France, bicycles under 6kgs are forbidden. Bicycles under this weight are incredible expensive and dangerous. Using metals like titanium and carbon fiber. Most light and simple(no suspension) road bicycles weight usually 10 kilos, most mountain bikes do weight 15-20 kgs. In Holland, most bicycles you see on the street are simple and cheap.

I think seanc probably has the idea of the saying right but with the wrong specific numbers.

Re: Vertically aligned carbon nanotubes triple the density of lithium batteries

#129

Post by Animats »

aaronblohowiak wrote: post #124
gpanders wrote: post #122

Earlier quoted context omitted.

Wrong. From the article: > Also, because there's gaps in that ultra-lightweight nanotube scaffolding and less extraneous binder and additive materials, a battery containing a given amount of active material can become much, much lighter and more compact. Energy density, both by weight and by volume, stands to jump by factors of 2-3.

There are both power and energy density increases!

We'll see. They ought to get the power increase, just from using something more conductive. The energy density increase looks like more of a maybe.

This isn't the first company to claim carbon nanotube batteries.[1]

[1] https://www.chasmtek.com/solutions/carbon-nanotube-lithium-i...

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