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First zinc-air batteries will hit next year in small form factors

Rechargeable batteries are used in so many different products that we use today – everything from our computers and mobile phones to our cars have batteries inside. One of the major areas of research is in new battery technologies that will increase the run time of electrical devices and make safer batteries.

Lithium-ion rechargeable batteries have been on the market for a long time and are prone to problems. The batteries, for instance, were the cause of massive recall several years ago after they were overheating in notebooks which in turn caused fires. One of the more promising new battery technologies being researched are zinc-air batteries.

These batteries are cheaper and have a significantly larger capacity for storing energy than existing lithium-ion batteries. Physorg reports that the average lithium-ion battery stores only a third of the energy that zinc-air batteries are capable of storing and cost about twice as much as the zinc-air counterpart.

A Swiss company called ReVolt plans to release a zinc-air battery next year. At first, the batteries will be small units that will be used in hearing aids. Later the batteries will come in larger forms for mobile phones and much later, the zinc-air battery will find its way into electric vehicles.

The zinc-air battery was developed by a firm called SINTEF in Norway and ReVolt was formed to market the battery. In a zinc-air battery, oxygen from room air is used to generate current. The air is used as an electrode and the battery contains an electrolyte and a zinc electrode in a casing that is porous and allows air inside. The zinc-air battery is much safer than lithium-ion batteries because there are no volatile materials inside the battery that could possibly catch fire.

The zinc-air battery produces electricity when the air electrode is discharged with the help of catalysts producing hydroxyl ions in the aqueous electrode. The zinc electrode then gets oxidized and releases electrons to form an electric current. When the battery is recharged, the process happens in reverse and oxygen is released into the air electrode.

The challenge for the researchers was to devise a method where the air electrolyte wasn’t deactivated in the recharging cycle to the point where the oxidation reaction slowed or stopped. The slowing or stopping of the oxidation reaction reduced the number of times that the zinc-air battery could be recharged.

Physorg reports that prototypes of the zinc-air battery have been tested through more than a hundred charge and discharge cycles. ReVolt hopes to increase the number of charge and discharge cycles to the 300 to 500 range. That number would make the batteries useful for cell phones and other electronic items that are recharged frequently.

The zinc-air batteries ReVolt is working on are also being developed for future use in electric vehicles. Before that point can be reached the batteries have to reach the point of being able to withstand up to 10,000 charge cycles.



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RE: AA?
By Cogman on 10/30/2009 12:03:44 PM , Rating: 5
Lion rechargeable batteries will NEVER be available in standard rechargeable sizes. The risk of some moron overcharging and blowing up their battery is just far too great.

You would have to put a charge circuit on every battery, which just isn't feasible.

Overcharge a NIHM or CICAD battery, and you destroy the battery life a little. Overcharge a Li-Ion battery, and you have the potential for a fire/explosion.


RE: AA?
By Cogman on 10/30/2009 1:11:03 PM , Rating: 5
Down-rate me all you like. But that is the truth. Standard battery chargers are fairly dumb. And there are enough out there that just charge for x minutes that there is a serious risk for batteries li-ion batteries to explode.

Every appliance that has a Li-Ion battery in, has a charge circuit somewhere to ensure that the battery doesn't overcharge. When these circuits fail you get "Help, my IPod burned a hole in my seat"


RE: AA?
By lewislink on 10/30/2009 2:20:06 PM , Rating: 2
That's the point about dedicated gadget LIs, they have the extra added charge circuit. The AA, AAA, C and D types would need the same charging circuit the dedicated kind have. That would make them too costly.


RE: AA?
By Cypherdude1 on 11/1/2009 3:11:04 PM , Rating: 2
Hello,
could DailyTech do something about your {PRINT} feature? When I want to print out an article, I use Adobe Acrobat's print to PDF feature not paper, the entire article is shifted to the left. Please fix your {PRINT} feature.


RE: AA?
By straycat74 on 11/2/2009 8:27:08 AM , Rating: 2
It works just fine with doPDF.


RE: AA?
By Mint on 11/1/2009 2:36:18 AM , Rating: 2
Why not just integrate a tiny IC that shunts current away when it's charged? This is not a hard problem to solve.

Lithium ion doesn't makes sense for standard batteries. You pay extra for the lower weight per Wh, but the devices that use them aren't really meant for ultimate portability anyway due to the wasted space of AA/AAAs vs. custom battery packs.

To top it off, NiMH has higher volumetric energy density anyway, so Li-ion wouldn't even last as long. How many people would buy a battery that's more expensive and doesn't last as long per charge just because it's lighter?


RE: AA?
By Alexstarfire on 10/30/2009 1:17:45 PM , Rating: 3
Or you be a bit smarter and just do that for the actual charger. Yes, you'd have to get a new charger for the batteries, but they'd be rechargeable, and safe at that.


RE: AA?
By Bruneauinfo on 10/30/2009 2:17:11 PM , Rating: 5
yeah, except the battery is standard and "fits my old charger I bought at Radio Shack back in '92 just fine!!"

---BOOM!!


RE: AA?
By Alexstarfire on 10/30/2009 2:52:17 PM , Rating: 2
Put a warning on the battery pack and leave it at that. If people are stupid enough not to read first.... then darwinism takes effect. We've been stopping it for a while and you see what the outcome is.


RE: AA?
By lightfoot on 10/30/2009 3:20:16 PM , Rating: 5
A lithium fire is a fair bit more hazardous than "Warning: Coffee may be very hot."

Do you even know how to fight a lithium fire??


RE: AA?
By Shining Arcanine on 10/30/2009 3:23:41 PM , Rating: 5
Put water on it. You will probably win a darwin award for your quick thinking.


RE: AA?
By bobsmith1492 on 10/30/2009 3:42:18 PM , Rating: 3
We had a lithium thionyl chloride pack explode at work, a couple of desks over from me. It was bad, but there wasn't a problem putting out the fire (I stomped on some burning papers...)


RE: AA?
By Alexstarfire on 10/30/09, Rating: -1
RE: AA?
By PlasmaBomb on 10/31/2009 6:53:54 AM , Rating: 3
Cars don't typically catch fire when you are "charging" (fuelling) them... even if you over do it.


RE: AA?
By Alexstarfire on 10/31/09, Rating: 0
RE: AA?
By lightfoot on 11/2/2009 12:34:32 PM , Rating: 4
A gasoline fire can easily be put out using a standard CO2 fire extinguisher, or any extinguisher that is not a water extinguisher.

Lithium however will continue to burn in a 100% CO2 environment. Also water cannot be used because Lithium burns in water. Standard ABC fire extinguishers are useless on Lithium fires and may actually make them worse. Lithium is a hazardous material and must be put out using a Class D dry copper powdered metal extinguisher, or smothered using something like dry sand. (Class D copper metal extinguishers are not likely to be found in most homes, cars or fire engines.) Standard Class D dry chemical extinguishers may or may not work on a lithium fire depending on the size and location of the fire.

The best response for a lithium fire is to isolate the fire, and let it burn its self out.

Lithium fires are by far the worst type of fire to fight, even for trained professionals. Gasoline is trivial by comparison.


RE: AA?
By Integral9 on 11/3/2009 9:39:16 AM , Rating: 2
Curious, Will HALON work?


RE: AA?
By lightfoot on 11/3/2009 2:28:30 PM , Rating: 3
Not according to the FAA.
quote:
Halon 1301 is ineffective in suppressing a lithium battery fire.

quote:
Halon 1301 chemically interacts with the burning lithium and electrolyte-with no effect on fire intensity

http://www.fire.tc.faa.gov/pdf/systems/Lithium-ion...


RE: AA?
By Fritzr on 10/31/2009 2:53:52 AM , Rating: 3
Already have that problem today with alkalines. You can recharge those disposable batteries using an alkaline battery charger. Put an alkaline in a NiMH or NiCad charger and you will probably see a fire. People generally do not try that more than once. :D

The alkaline chargers are available, just hard to find, which leaves people with the impression that they are "use once and toss in the trash". Could really cut down on the number of batteries in the trash if alkaline chargers became more common, but battery manufacturers much prefer you buy new batteries instead :P


RE: AA?
By mindless1 on 10/31/2009 5:43:03 PM , Rating: 2
Make stuff up often? No, if you put alkalines in a NiMH/NiCad charger they will burst from pressure buildup but there won't be a fire. The difference is that the alkaline electrolyte isn't subject to combustion when exposed to air.

The issue of alkaline chargers is not that they're hard to find, it's that the battery itself also has to be contructed to allow charging and in being so designed they become inferior in performance relative to other alternatives like NiMH, Li-Ion, and they don't recharge to anywhere close to the possible fresh/new capacity.

If people wish to throw away fewer batteries there are other options like NIMH, particularly the low self discharge models like Sanyo Eneloops.


RE: AA?
By DragonMaster0 on 10/31/2009 8:34:11 PM , Rating: 2
quote:
If people wish to throw away fewer batteries there are other options like NIMH, particularly the low self discharge models like Sanyo Eneloops.
Those are great if you want to use them in low-power devices such as clocks or remotes, where standard NiMH batteries only last a few weeks, but the available capacity is nowhere near as good as the best NiMH batteries out there.


RE: AA?
By mindless1 on 10/31/2009 10:20:35 PM , Rating: 3
Ah, but it's not that simple. Eneloops maintain a higher voltage per state of charge so they may actually power devices longer.

The most energy dense NIMH batteries also self-discharge faster so it may take little more than a couple weeks to realize an equilibrium. Further lots of people have noticed the viable lifespan of the most energy dense NIMH is lower, you may easily get twice the recharge cycles from the newest version of Eneloops and I vaguely recall they upped their recharge cycle capability even more recently.

Certainly you are right that in a continual frequent use/rapid drain scenario, Eneloops aren't the highest capacity but that is an arbitrary way of looking at it, no matter what the capacity is someone will wish "if only it were a little higher".

I've bought plenty of highest-capacity-possible NIMH over the years but these days, only buy LSD NIMH. It is pretty liberating to not be a slave to batteries anymore, gone are the days when I have to do something like think to myself "Ok I want to use the camera today so now I have to go charge batteries", instead I can just grab a pair I charged at leisure months ago so they are what rechargables always sought to be, replacements for alkalines that are ready to use when you need them.


RE: AA?
By MrTeal on 10/30/2009 8:19:06 PM , Rating: 2
Except that Li-Ion and Li-Poly have cell voltages of 3.7V instead of 1.2V for Ni-MH. So even if the charger had the circuitry, you still wouldn't have be able to use them in the same devices as regular AAs.

They really do need to come out with an industry standard package for Li rechargeables, but it has to be difference than the existing letter standard.


RE: AA?
By mindless1 on 10/31/2009 5:46:07 PM , Rating: 2
There are industry standard packages for Li-Ion rechargeables and contrary to the thoughts of some, a few of these are similar enough in size they could be installed in the wrong devices. For example,

10440 Li-Ion 3.7V -> AAA size
14500 -> AA
25500 -> C

18650 -> No *common* alkaline equivalent but industry standard size for laptops, etc.


RE: AA?
By DragonMaster0 on 10/31/2009 8:28:53 PM , Rating: 3
A Li-Ion battery cell works at an average of 3.7V, and a minimum voltage of 2.4V. You simply can't make an AA battery out of that, unless you place a voltage converter in the cell, which would take up all the space and leave you with a battery no better than a NiMH.

quote:
The risk of some moron overcharging and blowing up their battery is just far too great.
No, it just won't charge.

quote:
You would have to put a charge circuit on every battery, which just isn't feasible.
Consumers can't buy a Li-Ion cell without a charge controller anyways.


RE: AA?
By Mint on 11/1/2009 4:16:40 AM , Rating: 2
Even if you had a tiny voltage converter (quite possible nowadays), it still wouldn't last longer than NiMH. Here's the data on Wikipedia (other sources are similar):

NiMH:
0.4 kJ/g
1.55 kJ/mL

Li-ion:
0.46-0.72 kJ/g
0.83-0.9 kJ/mL


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