A discussion of battery technology

[Eeezee]

Originally posted by: bobsmith1492
Is there such a thing as superconducting batteries? Is the general idea to get current flowing in a loop and, since there's no resistance, it just won't stop and it can be tapped as necessary? I would think there would still be charge decay through stray magnetic flux and whatnot, ruling out the 100-year watch battery at the least and maybe making the whole concept a no-go. Plus we need to actually come up with a room-temp superconductor first... or, include a LN2 cooling system? That could be feasible I suppose.

You don't suppose it takes a lot of power to create that LN2? That's assuming we're talking about a superconductor that works at LN2 temperatures - most of them need to be even colder (LHe). Superconducting batteries aren't at all practical (for commercial use).

Room-temperature superconductors are... well, I don't know how well that's coming along, but my last impression was that they have no foreseeable breakthroughs.

 

[bobsmith1492]

Originally posted by: Eeezee

Originally posted by: bobsmith1492
Is there such a thing as superconducting batteries? Is the general idea to get current flowing in a loop and, since there's no resistance, it just won't stop and it can be tapped as necessary? I would think there would still be charge decay through stray magnetic flux and whatnot, ruling out the 100-year watch battery at the least and maybe making the whole concept a no-go. Plus we need to actually come up with a room-temp superconductor first... or, include a LN2 cooling system? That could be feasible I suppose.

You don't suppose it takes a lot of power to create that LN2? That's assuming we're talking about a superconductor that works at LN2 temperatures - most of them need to be even colder (LHe). Superconducting batteries aren't at all practical (for commercial use).

Room-temperature superconductors are... well, I don't know how well that's coming along, but my last impression was that they have no foreseeable breakthroughs.

Those are my thoughts exactly. I doubt effective storage and retrieval of energy is feasible even before considering the cooling system, though. It just adds more problems and complexity to deal with.

 

[Nathelion]

Originally posted by: Eeezee

Originally posted by: Nathelion
The problem is twofold though. Even if you make a good ultraportable battery, where are you going to get the actual electricity from? That's right, coal and oil...

Solar and fission...

Yes, coal will be a big source of our power for another 50 years probably, but we could so easily build fission plants.

And the entire southwestern US is a prime locale for solar power generation. The good thing about the warmer climate is very few people use heaters in the winter - in the city, it's plenty warm at night. In the southwest, electricity consumption peaks during the afternoon, right when solar power generation peaks, thus reducing the need for tons of nightly storage. Why do so many people have a problem understanding this? Arizona and California have millions of homes, and they consume the most electricity when solar collectors would be generating maximum electricity! IT'S PERFECT!

Warmer climate = more air conditioning. Just putting that out there.

 

[pm]

Originally posted by: bobsmith1492
Oh, no, no projects for me; this is indeed abstract but I'm a practical kind of guy by nature and I want to see battery technology advance. It seems to me that a breakthrough in electricity storage would revolutionize the modern world as we know it and I'm trying to keep my eyes open and see where it may strike.

P.S. I have a friend who was big into RC racing up until a year or two ago; everyone was still using NiCads for their super-low internal series resistance and great pulse current capabilities. Are these LiFePO4 cells taking over from NiCads? Is that because they have higher power density than NiCads?

From my perspective, there's no breakthroughs looming on the horizon for a production ramp in the next couple of years. There's plenty of ideas that show promise in the labs, but when it comes to the real world, issues such as temperature range and longevity and ability to handle large discharge and charge currents whittle away at the ideas. Some of the ideas involving nano-sized materials may (or may not) pan out. Super-capacitors are also on horizon... but they also have had issues in going from the lab to the store shelf. And, of course, fuel cells... I don't see a breakthrough coming any time soon. The closest we will get to a "breakthrough" is the incremental evolutionary step towards LiFePO4 cells which is in progress right now.

LiFePO4 are definitely taking over power tools on the high end from NiCd. NiMH have not traditionally been able to handle discharge currents higher than 5-10 times their capacity, nor charge rates higher than 2 times their capacity (ie. 10A discharge from a 1Ah battery) , so it's not a good choice for high-end/high-power power tools. So the industry stuck with NiCd, but are starting to migrate to LiFePO4 on the high-end (where money doesn't play as big a role). One other nice thing about LiFePO4 batteries is that they don't self-discharge (drain themselves when not doing anything) at anywhere close to the rate of nickel-based cells, so you charge a pack up in advance and know that it will still be pretty well charged when you get around to using it. Self-discharge from a nickel-based cell that's been "peak charged" is extremely fast (like in terms of % per hour).

On the RC car racing front... well, that packs are expensive and require new/different chargers. They have about twice (or better) the capacity of NiCd cells per weight/volume, last longer, are more tolerant of cold temperatures, and can be charged at faster rates. The high-end racing guys are definitely switching over, but for everyone else... the cells are pretty expensive. I see a lot of RC electric helicopter guys use them - particularly "3D" RC helicopters (where the helicopter flies upside down, does cork-screw spirals, like this: http://www.youtube.com/watch?v=j5Pwix-GXQ8 ) because keeping fuel flowing in gas helicopters in some of these moves is problematic.

LiFePO4 is moving very quickly for something that just came out of the lab a few years ago. Given the materials and manufacturing costs and the advantages over nickel-based chemstry cells, I think in a couple of years we will start to see widescale adoption in EV's, power-tools, and consumer electronics where high capacity is not the highest priority.

But it's not a breakthrough - when you look at the stats, it's not that much better than where we are presently.

 

[PolymerTim]

Originally posted by: bobsmith1492

Originally posted by: Eeezee

Originally posted by: bobsmith1492
Is there such a thing as superconducting batteries? Is the general idea to get current flowing in a loop and, since there's no resistance, it just won't stop and it can be tapped as necessary? I would think there would still be charge decay through stray magnetic flux and whatnot, ruling out the 100-year watch battery at the least and maybe making the whole concept a no-go. Plus we need to actually come up with a room-temp superconductor first... or, include a LN2 cooling system? That could be feasible I suppose.

You don't suppose it takes a lot of power to create that LN2? That's assuming we're talking about a superconductor that works at LN2 temperatures - most of them need to be even colder (LHe). Superconducting batteries aren't at all practical (for commercial use).

Room-temperature superconductors are... well, I don't know how well that's coming along, but my last impression was that they have no foreseeable breakthroughs.

Those are my thoughts exactly. I doubt effective storage and retrieval of energy is feasible even before considering the cooling system, though. It just adds more problems and complexity to deal with.

To be fair, thebeyonder was referring to room temperature superconductors in the first place, so there is no cooling system. And yes, you can store electrical energy in superconducting electromagnets (Link).
I was primarily concerned with the logistics of size and energy density as to whether they could really fill the rolls (eventually) that the beyonder suggested such as:

how about a watch battery that would last for 100 years, cost 3 bucks? a 1000 watt boom box you can take with you on the bus? heated clothes?

Just sounded a bit unfounded to me. Not saying it can't happen, just that there are a lot more requirements than high efficiency and charge/discharge rates (known strengths of superconductors) in order to meet these kinds of applications. My primary concern is energy density and I haven't seen any info on that particular quality.

 

[keird]

Originally posted by: silverpig

Originally posted by: Throckmorton
Didn't you guys hear about the brand new battery technology with 10x the capacity?

The silicon nanowires enhancement of lithium ion batteries? Yup

I was looking at this article regarding silicone and carbon nanotubes. The company said that they get 727 mAh/g. I wondered if that was good or not and in comparison to what other common materials. It's hard to find a reference.

 

[Throckmorton]

Originally posted by: Modelworks
I think things like converting aluminum to hydrogen are the way to go.
The aluminum pellets are easy to transport and safe.
You would just drop the pellets in your tank with a measured amount of water.
Hydrogen bubbles off, straight into the fuel line.


http://www.autobloggreen.com/2...ling-hydrogen-economy/

Woodall says that the reaction of aluminum with water has the same energy content per unit weight of oil, about 20,000 BTUs or about 6 kWh per pound. And, since aluminum is safe and plentiful, it has high potential to create "aluminum enabling hydrogen economy"

If you can catch it , watch the series Eco-tech that is running now on the science channel.
http://science.discovery.com/t...id=48.x.122449.34341.x

It had tons of new energy systems that I had not previously heard about.

Plentiful.. No it's not, for all intents and purposes. AL is the most common element in the earth's crust IIRC, but mining it is difficult and extremely destructive environmentally

 

[bobsmith1492]

Originally posted by: keird

Originally posted by: silverpig

Originally posted by: Throckmorton
Didn't you guys hear about the brand new battery technology with 10x the capacity?

The silicon nanowires enhancement of lithium ion batteries? Yup

I was looking at this article regarding silicone and carbon nanotubes. The company said that they get 727 mAh/g. I wondered if that was good or not and in comparison to what other common materials. It's hard to find a reference.

My first link in the op shows typical values for currently developed products. The best they have listed is the Li-ion at up to 160Wh/kg. The 727mAh/g doesn't really compare because it's not a measure of energy. Assuming it's a Li-ion relative at roughly 3.6V, that's 2617 Wh/kg so it sounds a little far-fetched to me (plus the opening paragraph didn't inspire much confidence in the article as it sounds like they have lawyers on the brain... "carbon nanotubes enable battery manufacturers to sue silicon...")

 

[bobsmith1492]

Originally posted by: Throckmorton

Originally posted by: Modelworks
I think things like converting aluminum to hydrogen are the way to go.
The aluminum pellets are easy to transport and safe.
You would just drop the pellets in your tank with a measured amount of water.
Hydrogen bubbles off, straight into the fuel line.


http://www.autobloggreen.com/2...ling-hydrogen-economy/

Woodall says that the reaction of aluminum with water has the same energy content per unit weight of oil, about 20,000 BTUs or about 6 kWh per pound. And, since aluminum is safe and plentiful, it has high potential to create "aluminum enabling hydrogen economy"

If you can catch it , watch the series Eco-tech that is running now on the science channel.
http://science.discovery.com/t...id=48.x.122449.34341.x

It had tons of new energy systems that I had not previously heard about.

Plentiful.. No it's not, for all intents and purposes. AL is the most common element in the earth's crust IIRC, but mining it is difficult and extremely destructive environmentally

That's the problem with large-scale efforts regarding engineering problems - the big-picture thinkers jump on ideas that are just not practical but sound good and work in some limited scope. Other examples: hydrogen burns clean so it was touted as the way of the future. Unfortunately hydrogen isn't just floating around waiting to be used; it must be produced with levels of inefficiency making it only a storage means, not energy source; massive infrastructure changes would be required for widespread use in transportation, plus the technology just isn't there to be cost-effective.

The whole compact-fluorescent light bulb idea is another. When you think of the cradle-to-grave lifecycle (higher production and disposal costs), use of toxic materials, and overall impact of their poor power factor on the electrical system the only benefit turns out to be at the consumer's power meter assuming they are used properly in the first place. Again, on a limited scope they look good but they are not an ideal solution in the broad perspective.

 

[keird]

Originally posted by: bobsmith1492

My first link in the op shows typical values for currently developed products. The best they have listed is the Li-ion at up to 160Wh/kg. The 727mAh/g doesn't really compare because it's not a measure of energy. Assuming it's a Li-ion relative at roughly 3.6V, that's 2617 Wh/kg so it sounds a little far-fetched to me (plus the opening paragraph didn't inspire much confidence in the article as it sounds like they have lawyers on the brain... "carbon nanotubes enable battery manufacturers to sue silicon...")

26.17 Wh/kg

I think that we don't have enough information. Even if it doubled the capacity, that's pretty significant. 220-320 Wh/kg would make a pretty nice battery. Aside from the environmental hazards from making the carbon nano tubes (CNT), I wonder if the addition of CNT would affect the operating temperature range; particularly the low range. 0 degrees Celsius limits military and aircraft applications. It would have to reach -40.

 

[MrDudeMan]

Originally posted by: bobsmith1492

Originally posted by: keird

Originally posted by: silverpig

Originally posted by: Throckmorton
Didn't you guys hear about the brand new battery technology with 10x the capacity?

The silicon nanowires enhancement of lithium ion batteries? Yup

I was looking at this article regarding silicone and carbon nanotubes. The company said that they get 727 mAh/g. I wondered if that was good or not and in comparison to what other common materials. It's hard to find a reference.

My first link in the op shows typical values for currently developed products. The best they have listed is the Li-ion at up to 160Wh/kg. The 727mAh/g doesn't really compare because it's not a measure of energy. Assuming it's a Li-ion relative at roughly 3.6V, that's 2617 Wh/kg so it sounds a little far-fetched to me (plus the opening paragraph didn't inspire much confidence in the article as it sounds like they have lawyers on the brain... "carbon nanotubes enable battery manufacturers to sue silicon...")

*taps sarcasm meter*

 

[Nathelion]

Regarding superconducting batteries, MRIs are basically giant superconducting batteries (some of them are, at any rate). But the intense magnetic field generated by the "battery" are used to watch the insides of your brain, the whole thing is not used to store and retrieve energy. They are unfortunately HUGE, very heavy, and there have been a number of fatal accidents when metal objects got too close to the coil.

 

[Mark R]

Originally posted by: Nathelion
Regarding superconducting batteries, MRIs are basically giant superconducting batteries (some of them are, at any rate). But the intense magnetic field generated by the "battery" are used to watch the insides of your brain, the whole thing is not used to store and retrieve energy. They are unfortunately HUGE, very heavy, and there have been a number of fatal accidents when metal objects got too close to the coil.

You should see what happens when the energy in an MRI magnet gets released (due to magnet malfunction, or someone pressing the emergency demagnetize button)!

(A magnet malfunction usually happens because a small area of the wire loses superconduction - as the current in the magnet wire is about 1000 A - this produces a lot of heat, causing the neighboring areas of wire to lose superconduction in a massive chain reaction. The emergency stop button actually activates a small heater on part of the wire, to make it non-superconducting).

This happened at my local hospital. The energy in the magnet has to go somewhere, and it ends up going as heat into the wire. The energy stored up to about 10 kWh for a standard scanner, 20 kWh for a high-end scanner, and up to 35 kWh for super-high-field research scanners.

The result is that the helium in the scanner boils, very vigorously, as the wire heats up. The scanner had a 1 foot diameter vent pipe, and when the magnet 'quenched' a huge jet of super-cold helium gas shot out, producing a huge cloud of fog - it looked like some bizarre kind of steam explosion. It was very impressive, but very expensive. It cost about $40k to replace the helium, and about 3 days of downtime, to restart the scanner.

Apparently, we were lucky. In the event of magnet 'quench', there is a very real risk, that the magnet may be damaged (due to sudden uncontrolled temperature rises damaging the magnet wire, massive mechanical forces as the electrical current drops, and pressure build up if the escape of helium is obstructed).

The person in the scanner at the time, felt the magnetic field go as the magnet dumped energy. The field collapsed so quickly, that it induced electrical currents in their body, causing muscle twitches and electric shock type sensations!

This is what makes me uncertain that superconducting energy storage is practical, for anything other than specialist UPS type purposes. You end up with huge magnetic fields, which may end up propagating for a large distance and are difficult to shield. Then, when the energy is drawn down, you get rapid changes in the magnetic field. You have to keep people and critters away, as with a powerful enough system, you could imagine things getting electrocuted from the discharging magnetic field.