Science news:Battery Breakthrough Based on Graphene Charges 10x Faster

[tech_freak]

I just found & read this few mins ago.
http://www.dailytech.com/Battery+Bre...ticle23288.htm

[JERRY2KONE]

These flash in the pan discoveries are always worth a look, but rarely emerge as anything more than an idea due to cost, or some other manufacturing issues. It all sounds great if they can only get it to work properly and move it into production. When it actually reaches some level of success they will more than likely move directly into production, or just sell it off. So I would suspect that it will be some time before we see anything of value if it even reaches that level.

[BrianG]

Originally Posted by JERRY2KONE

These flash in the pan discoveries are always woth a look, but rarely emerge as anything more than an idea due to cost, or some other manufacturing issues...

Or some big company buys the tech and sits on it so they can keep selling their inferior product...

[mistercrash]

Originally Posted by BrianG

Or some big company buys the tech and sits on it so they can keep selling their inferior product...

Sounds a bit like big oil companies with the help of our governments. But that's a whole different discussion.

[snellemin]

HUH, this is really old news. Flame company is allready way ahead with the 150C cells.

[BrianG]

Originally Posted by mistercrash

Sounds a bit like big oil companies with the help of our governments. But that's a whole different discussion.

Yeah, definitely a different discussion. Gov't and big oil; sounds like a typical conversation where people claim it's all conspiracy theory. It does make you wonder though; if some higher power wasn't controlling these new technologies, why do we never hear any follow-up stories? Not exactly headline-worthy, but it would sure be nice to know how these new breakthroughs pan out, if nothing else but just to know. That would be a pretty decent new TV show to watch IMO - something along the lines of Mythbusters where a team goes out and finds out what happened to "tomorrow's new tech"...

[JERRY2KONE]

Or even sharing some of their work related issues so the average Joe can share some new ideas to help them move forward through whatever obstacles that might be plaguing them.

[redshift]

Hey guys :)

Looks like this may really be moving forward...

[JERRY2KONE]

What else can you say, but WOW. This could be the new technology we have all been hoping for. The part that sucks is knowing that they are so close and not knowing how long it will be until this hits the mainstream. None of us are getting any younger, right. I figure I may have 20 to 30 good years left in me. I would love to see some serious revelations while I am still alive and maybe even able to use some of them. The idea of having not only a light weight solution that has the capacity to power a vehicle easily and with enough run time to make it worthwhile, but to be able to fully charge it in seconds instead of hours would be phenominal. Very cool stuff. Thanks for posting that video.

[redshift]

Good to see you Jerry

There's lots more videos on the topic and it seems to be under development pretty seriously.
I can foresee a vehicle structure being the battery, etc., yea that would be amazing!

I do wonder how the power density would compare to the highest discharge lipo (actual, not using Brand Flame's magical graph lol)

Looks very promising.

[JERRY2KONE]

Yea thanks Redshift. I am still hanging around, but just not posting as much. I spend more time over on the UE forum. It's just not as much fun with so many of the regulars not here like Lincpimp, TDC57, & even Harold does not post as much. I know its an RC site, but I miss some of the comical bantering that was part of the every day routine in here.

Anyway yea it does look promising. Something like this would seriously change the world as we know it.

[zeropointbug]

Yeah, we need ultra capacitor reliability/cycle life with the power of lipo, along with the energy density of laptop type cells (200Wh/kg at the VERY least), ideally, up around 400Wh/kg to be truly competitive with ICE cars.

[BrianG]

While this technology sounds very promising for certain applications, capacitors will never completely replace batteries. At least not without some serious changes in how the power is drawn from them.

A capacitor discharges in a logarithmic curve. Meaning, once a load is placed on the cap, it starts discharging immediately. At 1TC (time-constant), there is only 36.8% of the voltage remaining. After another TC, 36.8% of that voltage is remaining. And so on for 5 TC (at which the cap is considered discharged).

So, even if a 10,000,000uF (10F) 100v cap (which would be absolutely ginormous by the way) and is loaded with 10ohms, the TC is 100 seconds (TC=R*C). So, with 100v on the cap, that load would cause the voltage to drop to 36.8v in about 1.5 minutes (and current is dropping continually during this time) after just one TC. If the load "wants" 100v, the voltage on the cap is already unusable.

To get any kind of long-term usable voltage on a cap when loaded with anything more than an LED or two, it would have to be in the hundreds of farads, not micro-farads as they are usually rated, to keep the voltage during the first TC in a usable range. OK, so lets add in a switching PS device that would output a steady voltage regardless of the cap voltage (to a point of course). But even then, the ever-increasing load (as the PS draws more current to compensate for falling voltage) will just decrease the discharge time to something like 2TC total. So, using our 10F 100v cap example above, you could get maybe 3 minutes out of it instead of 1.5 minutes. Hardly seems worth it to me.

One of the articles about this technology does state the discharge and charge is more linear, so this would be a little different than the logarithmic curve of current cap technology, but still nowhere near similar to the relatively flat discharge curve of a battery.

No, I see these caps as supplemental devices that would be used along with batteries for larger-scale applications like EVs and the like. The caps would handle any extreme burst currents, so the battery would see more of a steady drain. The battery could then be designed to be more efficient at a more moderate discharge rating (no more 50C requirements) and smaller cells could be used as long as super-long runtimes aren't needed.

One of these articles states that you could charge a cellphone in seconds if powered from one of these super caps. Assuming these caps were hypothetically used with additional circuitry to power cellphones with a steady voltage supply, let's look at that for a second. A typical smart phone has around 2000mAh single cell battery. To charge that in 30 seconds, you would need a power supply capable of delivering around 240 AMPS at 5v. Hmm, yeah, I don't see myself rushing to hook up 2 gauge charging wires to my phone!

So, yeah, this technology does have merit (smaller size, simple/cheap to make, biodegradable, etc). But many of these "breakthroughs" tend to be over-hyped without much technical detail. To hear them talk about it, it is THE answer to all our woes.

By the way, exactly how did they make a graphene layer using a "standard DVD burner"?? In the video, they put the graphite solution on a DVD, put it in the tray, and out pops a graphene disc. I really don't think it's a standard DVD burner because; How does the disc spin at all without whipping the solution off the disc? OK, so maybe they used some custom software to spin the DVD reeeaaaalllly slow. But, how are they "burning" the disc when the laser is facing the underside of the disc? They put the solution-covered DVD facing up (duh, obviously), so is the laser burning through the disc before it hits the solution? Or did they mod the player so the laser is on top (which means it is not a "standard" burner).

[redshift]

Originally Posted by BrianG

By the way, exactly how did they make a graphene layer using a "standard DVD burner"?? In the video, they put the graphite solution on a DVD, put it in the tray, and out pops a graphene disc. I really don't think it's a standard DVD burner because; How does the disc spin at all without whipping the solution off the disc? OK, so maybe they used some custom software to spin the DVD reeeaaaalllly slow. But, how are they "burning" the disc when the laser is facing the underside of the disc? They put the solution-covered DVD facing up (duh, obviously), so is the laser burning through the disc before it hits the solution? Or did they mod the player so the laser is on top (which means it is not a "standard" burner).

Great points, I also wondered about the fluid flinging off, seems like about 4 rpm would be the max. I also doubt other details....

Another article I found (with some good comments)
http://www.kcet.org/news/rewire/scie...apacitors.html

And another recent video

[Kcaz25]

Thanks Brian for the technical explanation.