Posted by: moralee | March 20, 2009

Great news on Rechargable batteries

BIg news about batteries.
The following section of transcript is taken from the “Security Now” podcast. The full transcript can be found at www.grc.com/securitynow and the whole range of podcasts can be found at www.twit.tv.
This dialogue takes place between Steve Gibson of the “Gibson Research Corporation” and Leo Laport of “www.twit.tv

 

STEVE:  Okay.  So the big news from MIT in the last week appeared in the Letters section of Nature magazine, announcing MIT’s, well, two materials scientists, some chemists at MIT, have come up with a major battery technology breakthrough.  What they essentially did was they have come up with a technology for changing the surface crystallization in an otherwise standard lithium ion cell, where the surface is specially prepared to create a much more, effectively a porous to lithium ion surface.  The upshot of this is you can take existing lithium ion chemistry, which is well understood and well developed.  You switch it to using this particular electrode preparation.  And you can now fully charge and discharge a lithium ion battery in a matter of seconds.

LEO:  What?  Charge and discharge in – this is like those ultracapacitors that we were talking about.

STEVE:  Well, exactly.  In fact, in their paper they show the ways in which this technology is similar to ultracapacitors, even though it’s entirely different.  I mean, for example, as we know, the ultracapacitor owes its potential for high energy storage by using really high operating voltages.  Now, that’s the controversial aspect of an ultracapacitor, and actually it’s a problem with its application.  That is, if you were talking about, what was it, 3,500, 35,000 volts of charge, so you need to step up your available charging source up to that level, and you need to step – when you’re using the capacitor’s stored charge, you need to step the voltage back down to five volts if you’re going to be using this technology in a laptop.  So the beauty of using existing lithium ion battery technology is that we understand it, it’s mature, fabrication’s in place, and the charging and discharging, it’s operating at natural use voltages instead of something exotic.

LEO:  Well, how does it charge in nine seconds if it’s the same voltage?

STEVE:  Well, voltage and current are different.  So voltage is pressure, and current is flow.

LEO:  Flow.  It would need higher current; right?

STEVE:  Well, and so these guys – oh, yes.  And in fact, the current, the available current is the limiting factor.  For example, you could not – you cannot charge your plug-in hybrid vehicle in 10 seconds because you need too many kilowatt hours of energy.  So a vehicle with this battery technology could technically charge itself up in a few minutes, but you’d have to give it way more than household current.  So what you can imagine is, you can imagine the equivalent of a gas station, but now it’s an electron station, where you literally…

LEO:  A tank, you need a tank to fill.

STEVE:  Well, you literally drive your car up when it’s near empty.  You have some serious industrial-type connector which looks like some megawatt plug.  You plug it in, and this thing dumps a huge amperage of current into your car.  And in a matter of a minute, just like you’re filling your tank now, this thing could recharge your car’s next-generation lithium ion battery.

LEO:  That’s really amazing.  Now, what about a laptop?  Could you use – I guess you couldn’t – could you use it on a laptop?

STEVE:  Absolutely.  I mean, now, we’re probably two or three years away from this getting out into the market.

LEO:  Good, because I just bought a laptop.  I don’t want to buy a new one.

STEVE:  Yeah.  We’re probably two or three years away because, I mean, now, two companies, two producers have already licensed the technology from MIT.  So, I mean, everyone gets it that this is a breakthrough.  I mean, the days of charging up your cell phone or your PDA or your Kindle overnight, that’s going to be gone in a few years.  And I can imagine somebody four years from now listening to this podcast, it’s like, what?  You had what?

LEO:  All night?

STEVE:  You guys used to have to do that?  That’s crazy.

LEO:  This could be a huge breakthrough.  And what I love about this, as opposed to ultracapacitors, is it works with existing battery technology.

STEVE:  Yes, yes.

LEO:  How much of a change is it?  Do they change how they manufacture them?

STEVE:  Well, yes.  Again, this is all in the lab.  And these guys, they talk in this paper, none of the – this is in the press a lot this week.  But all the stuff in the press is just sort of your top-level surface junk, and it didn’t really talk about how this works.  So I bought a PDF from Nature of their paper, which is deep in chemistry and material science.  And it talks about how they – what they make this of, that this is a lithium iron phosphate electrode, which they heat to 600 degrees for some length of time, then they raise it to 900 degrees, and they do this and that.  And they understand, being materials guys, that what they’re doing is they’re changing the surface, the crystalline surface structure at the nano level so that it is far more permeable to ions.  And it’s the ionic permeability of the electrodes which have traditionally limited the rate at which you can charge and discharge lithium ion cells.

And they’ve got charts and diagrams.  And they show, for example, they state in their paper that the typical power rate, okay, so that’s not the total amount of energy, but the power rate, the rate at which you’re able to take power out of a lithium ion cell, the traditional lithium ion cell, is between 0.5 and 2 kilowatts per kilogram.  So think of it, between half and 2 kilowatts per kilogram.  In their test cells, using their modified lithium ion phosphate electrode, they’re able to get 170 kilowatts per kilogram.  So from 2 to 170.

LEO:  Wow.

STEVE:  So it’s orders of magnitude.  And that was a full discharge of the battery.  They charged the battery up, topped it off, just like you do any lithium ion battery, although much more quickly, and they discharged it fully in nine seconds.  So they dumped all of the battery power out in nine seconds.  So, I mean, what this means, as you said, you asked for laptops.  We’re back again to plugging it in and counting maybe to 10, or maybe to 100.  But, I mean…

LEO:  That’s great.

STEVE:  …no more hours required to charge.  See, right now…

LEO:   But, now, we wouldn’t need a special charging station, though; right?  I mean, again, we need extra current to flow that much – or maybe not.  Is a battery, a laptop battery that much current?

STEVE:  And that’s my point exactly, is that we’re not talking about filling up a car battery.

LEO:  Right, right.

STEVE:  We’re filling up a laptop battery, so…

LEO:  You could do it on your standard, whatever it is, circuit.

STEVE:  Well, it will be different charging technology.  So, I mean, it’s not like we’re going to be able to get new batteries and stick them in our old laptops because that won’t happen.  It’ll be the next generation of laptop.  It will work only with these next-generation batteries.  And so when you plug your laptop adapter into the wall, okay, the house lights will dim a little bit.

LEO:  That’s not good.

STEVE:  But only for 30 seconds.

LEO:  For nine, nine seconds, yeah.

STEVE:  It’d be like running your microwave, where you can sort of, ooh, wow, this is sucking some power out of that.  But in 30 seconds your hamburger is hot.  And in this case…

LEO:  Now, this would also increase the capacity; right?  We should be able to get much longer life out of these; right?

STEVE:  I don’t think that’s the case.

LEO:  It’s not, okay.

STEVE:  Because it’s still using – and they don’t directly address this in their paper.  And if it did increase the capacity, they certainly would have addressed it.  Because it is using standard lithium ion technology, they just solved the rate at which you can charge and discharge.  Now, the other reason that’s important is that, well, first of all, it means that you solved the problem of recharging, given that we actually would create electrical recharging stations the way we have gas stations now.  But say that we stayed with a hybrid model.  The problem with traditional hybrid technology, where you’ve got a gas engine, an internal combustion engine, is that there are better ways to convert fuel, gasoline, to electricity than an internal combustion engine hooked to a generator.  What you really want is an external combustion engine.  And that’s called a turbine.

LEO:  Ahhh.

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