How a Microscopic Supercapacitor Will Supercharge Mobile Electronics
spectrum.ieee.org
spectrum.ieee.org
They need a laser with precision control and where better to find one than in a device like that.
Lightscribe IS a DVD burner; in addition to burning DVDs, it lets you write patterns on the other (non-data) side. This uses that ability to etch the solution poured on the top.
I expect that we'll see a lot more in this space over the next 6 to 18 months. Perhaps it was what Elon was eluding too with his range statements.
https://www.youtube.com/watch?v=HCGtRgBUHX8
Another way to think about it is to compare Energy Density to larger scale things we have closer experiences with, such as Gasoline
https://en.wikipedia.org/wiki/Energy_density
The difference between a fire and explosion is really how quickly you can release the energy potential, so capacitors should be rather interesting in that case.
The thinnest metalized, plastic film capacitors have a plastic film 600nm thick.¹
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¹ https://en.wikipedia.org/wiki/Film_capacitor wherein you will also learn that the process of making the ends of the metalized plastic conductive by a "schoopage" process, named after Max Schoop who invented combustion spray method for the application of tin and lead. And now I am lost down the internet wormhole, "Detonation thermal spraying" is a thing! Explode your contacts into place!
Capacitors are much more prone to becoming coulomb bombs than batteries mostly because they are designed to discharge quickly, which is what makes them implicitly good bombs. It doesn't take much electron movement to make an explosion.
In fact, this is how alkali metals react with water. We learnt that only in the past few years.
http://www.nature.com/nchem/journal/v7/n3/full/nchem.2161.ht...
A pound of hamburger releases about 1152 kcal, or about 4.8 megaJoules of energy when metabolized over a day or so after it's eaten.
One pound of TNT releases about 2 megaJoules of energy in a few microseconds when it's detonated.
Big difference in the results. One makes me fat. The other makes me dead.
I'd be worried about a super capacitor that contained a week's worth of my laptop energy, and that might release it in a second.
Well both makes you dead, but at different rate...
Batteries store energy in a reversible chemical process. In so doing their ability to discharge that energy is limited by the rate at which that reaction can occur internally. The reaction is exothermic so the batteries get hot and sometimes catch on fire. Lithium ones are particularly nasty as the materials are reactive with oxygen in the air so once the battery begins to disassemble itself the additional reactions are started.
Capacitors on the other hand simply store charge. There is no chemical process involved and so their internal resistance is much much lower (it is basically the metal conductivity of the plates and the wires to the plates). So a capacitor with with the equivalent of 2mJ of charge, can release it all in picoseconds. [1] Such an energy release would be indistinguishable by people observing it from any other high explosive detonation. Further is would have no warning, batteries at least get hot, then start smoking, and then catch on fire. This would simply consume what ever conductor had shorted it and immediately turn it into a raging ball of plasma.
[1] I once considered a supercap as a "fun" battlebots weapon with the 'fork of dooooom' which when it hit your bot would vaporize that section.
Really? That's novel.
One of the proposed applications is for bursty current applications which currently have batteries with more capacity than required in order to serve peek current demands, but I rather doubt cell phones are in that category.