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General Misc => Misc => Topic started by: pomprocker on March 11, 2009, 02:38:01 PM

Title: Li-ion batteries recharge in seconds
Post by: pomprocker on March 11, 2009, 02:38:01 PM: http://www.tgdaily.com/html_tmp/content-view-41686-181.html (http://www.tgdaily.com/html_tmp/content-view-41686-181.html)
Title: Re: Li-ion batteries recharge in seconds
Post by: HDL_CinC_Dragon on March 12, 2009, 03:21:25 PM: Wow thats intense! I have my doubts about its capacity though.
Title: Re: Li-ion batteries recharge in seconds
Post by: Admin on March 22, 2009, 02:16:48 AM: I have serious doubts about this . . . for a start, it could be like a super capacitor. It stores huge amounts of power, and charges/discharges much quicker than a battery, but its *very* inefficient and can even could blow up if you discharge it too fast.

Now lets say you have a 4000mAh battery that's rated for 6V, and it charges in ~15 seconds (what the article reports). How many watts are passed at any point in time?

If I did the math right, assuming 100% efficiency, charging in 15 seconds, that's 5760 watts. What charger, or wire gauge, you think can handle that?! A regular PC only does ~100 watts. Its like having 57 PCs hooked up to a single wall socket - instant fire.

A car battery, say rated at 24V and 15000mAh, would be like 86400 watts (assuming 100% efficiency). Sure, it could charge that fast, but no home wall outlet could do that!
Title: Re: Li-ion batteries recharge in seconds
Post by: madchimp on March 22, 2009, 09:39:58 AM: Quote from: Admin on March 22, 2009, 02:16:48 AM
Now lets say you have a 4000mAh battery that's rated for 6V, and it charges in ~15 seconds (what the article reports). How many watts are passed at any point in time?

If I did the math right, assuming 100% efficiency, charging in 15 seconds, that's 5760 watts. What charger, or wire gauge, you think can handle that?! A regular PC only does ~100 watts. Its like having 57 PCs hooked up to a single wall socket - instant fire.
Well I would think they wouldn't have to be charged at the full rate but of course it would take a little longer. As far as instant fire that's what circuit breakers are for. If they do work out there would have to be changes but it wasn't too long ago and the amount of power a simple microwave took would overload circuits, and still does in some places. As far as electric cars even with these fast charging batteries I think completely electric cars just wont work. I for one like to have heat in the winter and ac when stuck in traffic in the summer and both of those would kill even high capacity batteries rather quickly.
Title: Re: Li-ion batteries recharge in seconds
Post by: TrickyNekro on March 23, 2009, 04:06:23 AM: Hehe.... Admin is right....
Even capacitors don't charge so quick....
Of course, in the future we will react charging currents of some serious Amps.... but still....
there is alot way to go......
Nano structures won't handle some Amps!!!!!
So it's pretty difficult to make a very small, and fast charging /discharging battery...
Title: Re: Li-ion batteries recharge in seconds
Post by: Admin on March 23, 2009, 04:27:50 AM: Thinking about this some more . . .

I suspect these researchers are basing these charging times off of non-verified calculations and/or unrealistic experiments. They would have explicitly specified how they were charging these batteries otherwise, because its not a simple task!

Also coming to mind is safety. Its bad enough that lithium batteries today catch on fire . . . think what happens if you get a short with these high discharge rate batteries! I can see expensive power regulation electronics being required . . .