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Battery Development Off The Beaten Path
Roland Piquepaille writes "Let's face it. Our computing devices are going faster year after year. But our laptop batteries don't show the same performance improvement. They still work only for a few hours, just a little bit more than ten years ago. Several companies want to change this, according to this UPI report, 'Nanotechnology improving energy options.' For example, mPhase Technologies plans to introduce smart batteries based on millions of silicon nanotube electrodes. These nanobatteries, to be introduced before the end of 2005, will last longer than traditional ones and will be respectful of our environment. Meanwhile, Konarka Technologies wants to reduce the weight of batteries with its flexible solar-fueled nanobatteries. You'll find more details and pictures in this overview."
Does anyone else see a problem with a battery that requires a voltage change in order to provide power? Will we need old fashioned batteries for our new high-tech batteries?
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How there is so little development in the energy sector.
Im serious.
Weve been using the same fuel for ages. That fuel explodes.
Perhaps Im jaded, but why, exactly, cant we economically synthesize fuel? (Perhaps that goes against the laws of thermodynamics?)
Meh.
Im bitter.
I think these new battery developments has more than just applications for longer-lasting batteries for laptops, PDA's and cellphones.
It could also mean substantially lighter battery pack units for hybrid drivetrains. A big issue with hybrid drivetrain cars is the fact the battery pack does take up quite a lot of space and also contributes to the deadweight of the car. By switching to these newer battery technologies they could reduce the size of the battery pack, which means more interior space and possibly even better fuel efficiency since when the gasoline engine is running you use less fuel because the car is now lighter.
I didn't see anything about the proposed cost of such a battery. I would guess it would be prohibitively expensive.
That said, CPUs and other components are designed these days to eat up less and less power, so perhaps there isn't even a need for more efficient energy storage?
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Conventional (electro-chemical) battery technology is pretty much at a dead end. The energy density of a battery is not far off from that of dynamite, which means that there really isn't any further you can go while keeping the result stable. (A fuel cell is really a highly UNstable battery, but extra safeguards can make it usable technology)
Since many useful applications are now limited by battery life, this is an area where a technological breakthrough is highly overdue...
They have gas-battery powered cars, so how about gas-battery powered laptops? And for the long airline lights just make sure it can handle jetfuel.
It's too bad nobody has found an effective way to "resuse" the heat generated by laptops to recharge the batteries.
Maybe we'll come full circle and have wind-up laptops; as your laptop starts slowing down, just wind it up.
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I've said it before, and I'll say it again. Stirling Radioisotope Generators are the way to go. Even if we're just talking about ruggedized military gear as an initial market, batteries that last for 10-40 years is a HUGE advancement over what the US is using today. And with military gear becoming more and more power hungry, can we afford NOT to look into radio power generation?
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I always thought the seeming lack of battery longevity improvements was more from end-user manufacturer designs than from technology improvements.
It seems to me that the manufacturers of products that use these batteries know what an acceptable length of time between charges is for their product and may not see the need to improve much upon that. What they do is convert the improved length-of-life to smaller electronics. They reduce the size of their product (smaller battery) while maintaining how long it can last between charges.
Fuel cells? I can see the headline now:
"Man drops his cell phone and dies in explosion."
I took a class on ubiquitous comuting last year and what we studied about battery power suggested that the technology existed for more powerful batteries, but the current technology was entirely too dangerous to use with portable devices since they get beat up considerably. We don't have this danger level for the rest of the tech industry. If we did, I imagine that computers in general would be far less advanced.
How about a system for charging in a microwave oven? Pop it in, give it 30 seconds and you're good for hours--just don't put anything in that isn't microwave-chargable!
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Actually, the energy density of dynamite and other explosives isn't that much. Gasoline has more energy density. Forget about computers, if we could get a battery with the same energy density as gasoline, at a reasonable price, that would mean practical electric cars.
Super-iron battery
An article in C&ENews (16/8/99) describes a new high-energy battery developed in Israel using iron as the cathode material. The new batteries store 50% more energy than the alkaline battery which uses a zinc anode, manganese dioxide cathode and potassium hydroxide electrolyte. The new cathode material which replaces the MnO2 has been termed 'super-iron' by Stuart Licht, Baohui Wang and Susanta Ghosh its inventors, however, it is not iron metal but an iron(VI) compound. iron(VI) is an unusual high oxidation state of iron which is strongly oxidising, an important property of a cathode material in a battery. These ferrate(VI) compounds have formulae such as K2FeO4 or BaFeO4. In operation the iron(VI) is reduced to the more stable iron(III) according to the cell reaction:
2MFeVIO4 + 3Zn -- FeIII2O3 + ZnO + MZnO2
The problem with using iron(VI) compounds before has been their stability. However, the researchers discovered that they were stable for months in KOH if the iron(VI) compounds were free from nickel(II) or cobalt(II) impurities. The material has a high energy density and a high electrical conductivity so it can be discharged rapidly. The cathode is also compatible with nickel hydride anodes and shows some degree of rechargeability. It is a long way from laboratory to supermarket, but we may well see 'super-iron' batteries on the shelf in the next millennium.
(Science 285, 1039, 1999)
******
Lets see;
Lead Acid in the first laptops, then NiCD, then NiMH, now Li-ion. The cells have not only gotten lighter but can also store energy with higher density.
I'd love to see double the capacity in batteries but isn't this going the wrong way? If a device could be made to use 40% less current, wouldn't that be easier than trying to squeeze 40% more capacity into a cell?
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... some one from the Uk spy services went to Exide batteries because their spy radios were hampered by the fact that the current charge density / weight / volume of batteries was too low and resulted in low battery life or a spy radio that was bigger and heavier than the spy who was supposed to carry it...
The Exide mas was asked if they could increase the charge density somehow, the response was immediate, "Yes."
The spook was somewhat nonplussed, as this was not the answer he was expecting, so he then asked if Exide could do it, why didn't they?
This response was also immediate.
"We sell more batteries."
That was 60 years ago, why does anyone think anything has changed?
(esp when detroit is now producing SUV's that get worse mileage than 50 year old 500 cubic inch big block engined cars)
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- Charge time
- Cold start (along with heating and defrosting) - battery powered are well and good for Florida, Texas, or California but may have issues north of the Mason-Dixon line.
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How about reducing power consumption instead of increasing battery life. Yes, I know that people are working on lower and lower power CPUs etc, but these are just low powered versions of our conventional, tied-to-the-wall desktop machines.
For truly low powered processors, we need asynchronous logic. Current CPUs, when nothing is happening, close down bits that they think are not being used and slow their clock rate. This reduces, but does not eliminate, power consumption. Asynchronous logig, on the other hand, whenit is not doing anything - does nothing. Nothing clocks, nothing changes state.
Then the displays. We need ambient light displays, as opposed to self-illumiated ones. We don't usually sit in the dark, to why have a dispalay that assumes we do? Some of these are being sold as "digital paper" or similar. Unlike CRT, LCD or Plasma, when the display is not changing, they consume no power. Only B/W so far, I believe - but I would rather a B/W display I can read than a ulesless lump with a flat battery.
Which means that we need to rethink the OS. The steady state of the screen must be still. We are fattening ourselves up on animated this and that. We need to rethink this. We need to research hoe to make the pointer flip the minimum number of pixels as it moves. A flashing cursor is a waste of energy: find better ways of indicating the current position. Maybe WYSIWIG is too expensive: go back to type-and-preview: only a single character changes for each keystroke, so only about 30x20 pixels need redrawing. And scroll by a few lines at a time, so that you don't have to scroll often.
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In this months Popular Science, they were running a brief article in the "What's New" section (sorry, not available online) that talked about a company using the technology in the "bed-of-nails" nano-battery to make materials that could be made either extremely hydrophobic or hydrophilic with the flick of a switch. This has the potential of making rather efficient mechanical systems by increasing the effectiveness of lubricants a great deal. Interesting that it's also being used to make batteries.
Their RPC cells seem to have a power and convenience advantage over almost everything else.
Really, you want to put plutonium, polonium, or other dirty bomb materials in the hands of the general public?
The dangers of these radioisotopes have been highly overrated. You'd do just as much damage by dispersing a lot of the toxic chemicals that are in today's batteries.
SRGs are a wonderful idea for military, for space, and for other heavily regulated and monitored uses (where RTGs are already used), but they're a horrible idea for the mass market.
As I said in my previous post, I'd be ecstatic if the military was the first market to use said batteries. Then they could stop worrying about how to power a soldier's equipment for 3 days, and start worrying about keeping his carry on food supplies large enough to keep up with his equipment.
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One - Practical implementations of Stirling Engines are rare. There are reasons for it that I am sure someone can explain. The elegant thermal cycle is well understood.
Two - Radioisotopes are rather difficult to turn off. If they disperse enough energy to make my laptop go for 9 hours of the work day, they are also generating energy/heat the other 15 hours. Stuff that laptop in a padded bag, put in trunk, wait a few hours and have a china syndrome car-b-que. It is a matter of energy conservation...it has to go somewhere!
You propose as an option a square piston in the engine...the trouble with this is sealing and wear at the corners. Also, precision boring and turning operations can holder better part to part tolerances.
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One - Practical implementations of Stirling Engines are rare. There are reasons for it that I am sure someone can explain. The elegant thermal cycle is well understood.
:-)
Fair enough. But they have been developed by NASA, and have been shown to be an effective way to produce quite a bit of power for not much radioisotope.
Radioisotopes are rather difficult to turn off.
This is the classic problem. You'd have to dissipate the excess energy in something like a heating coil or a mechanical fan. Dissipating about 30-40 watts shouldn't be too difficult, although it might get a smidge warm.
You propose as an option a square piston in the engine...the trouble with this is sealing and wear at the corners. Also, precision boring and turning operations can holder better part to part tolerances.
I've been curious as to whether this was a good design or not. Unfortunately, trying to get any *real* feedback has been worse than pulling teeth. Using a circular bore is certainly not out of the question. I only proposed a sqaure bore to reduce the footprint of the engine.
BTW, thanks for the feedback. I really do appreciate it.
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For the very first stoke this will work fine, but after the pressure escapes through the exhaust port. The remaining air in the cylinder is still heated so you will no longer get any thermal expansion from that same air.
:-)
Hmm... I thought that air-cooled Stirling engines worked because the heat would attempt to equalized the temperature inside the cylinder and outside in the open air. Perhaps I was incorrect. Many Stirling designs actually call for some sort of active cooling. NASA uses cycled helium for this purpose.
This is assuming you're not using some spring or relying on the momentum of the shaft somehow.
I was planning that the momentum would be sufficient to keep the device running. However, I have also been concerned about this problem. My alternate design actually has two "half-size" pistons connected to the dynamo. When one goes up, it forces the other one down. It may even make sense to offset the drive shaft such that one piston will finish moving the other piston up (thus exposing more of an air exchange outlet) before driving it back down.
Just my non-expert two cents.
It's more feedback then I ever got from the "experts" on the energy newsgroups.
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One could also think, that the overall technical progress may help to extend the battery life. Besides the hardcore gamers, most of us don't have to upgrade our computers so often because nowadays have the necessary computing power to fit our needs.
As seen with Transmeta and some other laptop innovation trends, it means that the industry is not focused only on performance anymore. It seems that making low voltage devices is the future trend. If you can't change the batteries, change the devices instead.
There is a feul cell in development that takes glucose from the bloodstream, converts it to electricity and urea. It is supposed to be used for things such as pacemakers. If you eat 4000 calories per day and hook one of these up to your laptop, you can provide a constant 90 watts and still lose weight!
Soon, the stereotypical nerd will be sickly skinny.
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I don't see how that follows. The batteries are mostly used for regenerative braking and for storing enough power for acceleration. The reason they are so large is that if you discharge them all the way it tends to damage the battery so they are only slightly discharged. THIS is the real problem with hybrids, if you had a battery technology that could handle being fully discharged you could remove a lot of battery mass.
TDI volkswagens get about the same mileage as a gas hybrid. They are definitely slick.
Then again, the CRX HF (1.3 liter I think) got about 50mpg freeway, but the CRX is a deathtrap, it's too small to have meaningful crumple zones. The hybrid civic is much safer, as odd as that sounds.
As for using diesel-electric or gas-electric like a locomotive, how do you figure that's going to be more efficient than a small gasoline engine hooked up to a modern transaxle? The kind of electric motors used in a hybrid are about 85% efficient at best. Even using a dedicated generator or alternator at the power input side, I doubt you'll get better than 90% efficiency, and the motor will still be around 85% efficient. 15% is a lot of driveline loss for a rear wheel drive car with a transmission, floppy drive shaft (drive shafts flex a lot more than you'd think) and these transaxles will have considerably less. Locomotives aren't diesel-electric because it's efficient, though they wouldn't be if it were horribly inefficient. They do it because it's a lot easier to control power delivery to the wheels (and thus the rails) using electric motors than some big complicated gearbox.
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All the solar energy in a 10x10 mile square is not enough to power the US.
10x10 = 100 sq mi ~= 260 million sq meters
The sun puts out (very roughly) 1000 watts of energy per square meter. This means our square will produce 260 GW (million KW). According to Google, the all the US power plants combined at full capacity produce 690 GW. So we're off by factor of almost 3, even assuming: 100% efficiency, constant direct sunlight round the clock.
A more accurate estimate would use this reference: "In Baltimore, Maryland, USA, for example, a flat array will receive about 1400 kWh/m2 per year." This means
1400/(365*24) ~= 0.16kw per sq meter.
This gives us 41.6 GW for the square. Off by a factor of over 15!
So, it's way off, but not ridiculously so. Consider that the numbers would be pretty close if we used a 40x40 mile square (665 GW).
The real problem, of course is storing all that energy for use at night!
Umm... you didn't draw a Stirling engine my friend. Seems you have a hole in it! In your drawing, your exhaust hole will not only bleed out heat(T), but it will bleed out the air itself (n).
:-)
:-)
I've long lost the link, but I had based it on a open air design I saw somewhere. The idea being that the piston would pass the exhaust port on the way up. When the exhaust port is reached, a heat and air exchange would occur. In the design I saw, gravity was supposed to bring the piston back down to compress the gas. Hmmm... oh well. If it doesn't work, time to move on to the next design.
I also have a problem with your heat source, because it's not a heat source, but a radiation source.
It is a radiation source, but the radiation is converted to heat as it strikes the walls of its container. If you hold a rock of Pu-238 in your hand, you'll find that it's quite warm. In fact, Pu-238 gives off sufficient heat to boil water.
This will be even less reliable than a gas burner when it comes to regulating production, because you added even more time to the heat transfer process
You wouldn't want to regulate production. The radiation is predictable enough to where it should produce a constant level of heat. This heat can be used to create the same amount of power, non stop. If the battery begins to overcharge, the device would need to bleed off the extra energy in either a small heating coil or a mechanical source such as a fan.
Thanks for your help! I'll ponder this a bit and maybe produce a more viable design. Maybe one day I'll even find a way to build a prototype.
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That's a 700-800 mile range on a single charge, not even Diesel vehicles get that.
:)
But a diesel vehicle can have it's tank refilled in 10 minutes. It'll take several hours to recharge a bunch of Li-S cells. The solution would be to have fuel stations keep stacks of batteries fully charged - rather than going to the fuel station and recharging your own batteries, you could hand in your discharged batteries and pick up some freshly charged ones. The fuel station can then charge your discharged batteries over a few hours and hand them out to someone else. The upshot is that the batteries don't really belong to you and I guess it'd be the fuel station's job to replace them when they wear out.
Of course, the size of the battery to power a car is going to be pretty huge, so there would need to be an easy way of swapping it without heavy lifting.
How exactly do you "refurbish" worn out batteries BTW?
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