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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 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.


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