How to store Li-ion batteries?

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Haggai
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How to store Li-ion batteries?

So, now that I have my first li-ion batteries (gray UltraFire 2400 mAh), and after reading about all sorts of trouble this chemistry can give, I wonder how to store them safely.

I know that most of the trouble comes with charging overly discharged cells, or overcharging, or damaging the battery structure, but I've also heard about a flashlight exploding in "off" state (http://budgetlightforum.com/node/1370). Undecided

Is it safe to store them in a flashlight? (one battery in each flashlight)

Is it safe to store them in a plastic box?

Maybe I should use some metal tool-box I have (with them in plastic boxes, of course, so as not to make electrical contact)?

Edited by: sb56637 on 02/14/2012 - 08:19 Reason: sb56637 replaced budgetlightforum.cz.cc with budgetlightforum.com via Scanner Search and Replace module.
Don
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I tend to keep mine in lights.

If they aren't going to be used for a while discharge them to about 3.6-3.7V as they will retain capacity better.

When mine aren't in lights they are in plastic boxes on a bookshelf - Maplin (The very expensive UK equivalent of Radio Shack in the US) sell this nice little box with an internal tray just made for 5 18650s or 10 16340s. The boxes are actually made by Raaco in Denmark - but just about every other plastic container I see on sale here is made in Israel so you ought to be able to find something suitable locally and probably a lot cheaper.

box

 

Those stored in a metal toolbox (Preferably on something heatproof and non-flammable) should be plenty safe enough. Do not use a sealed container - hot gas in a sealed container will eventually explode adding shrapnel to the general hilarity. 

While lithium cells can and do very occasionally go bang - it isn't all that common. Every cellphone/MP3 player/electronic gadget contains a lithium cell these days. And only a tiny number go boom.

 

In the very unlikely event that one does burn, get as far away from it as you can and keep everyone away from it till the burning stops - they emit several very nasty gases when they burn which you really, really don't want to inhale. And don't try to put the cell out with water, that will make matters dramatically worse.

 

All the cells I have that have failed with age or use have failed entirely undramatically - one leaked a nasty-smelling liquid, but the rest just stopped holding a charge. I have six well-used 14500s that can muster 334mAh in total. It used to be around 4000mAh.

 

Abuse is another matter. A good way to blow up any cell is applying a lot of volts and amps (outdoors) to it. This will burn up just about any cell, not just lithium ones.

 

The numbers from my light tests are always to be found here.

https://spreadsheets.google.com/ccc?key=0ApkFM37n_QnRdDU5MDNzOURjYllmZHI...

Haggai
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Thanks for the info.

I'll have to think about something practical when I leave home. I have two cats and I don't want them to inhale battery smoke when I'm not home... Maybe I should store them in the garage in that metal box. We'll see.

 

BTW, even though you see many boxes made in Israel, I've never seen even AA/AAA boxes in any store, let alone li-ion boxes. (haven't seen any li-ions at all, also)

I grabbed some boxes from eBay, 2 for 1.5$ or so (but not as good as the Maplin one), hope they'll arrive soon.

sixty545
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In addition to Don's outstanding advices: If you keep the batteries in your lights, don't have them standing at the fireplace, they are much better off in a cold room.

And be prepared that your Li-Ion batteries loose about 20% of their capacity each year whether you use them or not unless stored optimally (3.75V and cool).

Budgeteer
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+1

For being concerned to the health of your 4 legged furry companions.

kragmutt wrote:

They're gonna send you a green redcat with a black LED.

ky70
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Nice topic. 

Don, I keep a handfull of fully charged li-ons (14250, 16340, 14500, 18650) as back up batteries for my various lights for any emergencies.  Is it bad idea to have fully charged li-ons stored away that may not be used for a couple of months?  If so, what do you do/should I do for back up power...especially with the 18650 where a primary battery is not available.

Thanks

 

Budgeteer
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I have 2 fully charged. The rest in a drawer at 3.6 or so charge. Ambient temp 23 degrees.

Bought some boxes like these. Not used once. :/

This seller also sells a bunch of various sized battery holders usefull for making packs or other DIY frivolities. (Along with other inutilities)

kragmutt wrote:

They're gonna send you a green redcat with a black LED.

Don
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ky70 wrote:

Nice topic. 

Don, I keep a handfull of fully charged li-ons (14250, 16340, 14500, 18650) as back up batteries for my various lights for any emergencies.  Is it bad idea to have fully charged li-ons stored away that may not be used for a couple of months?  If so, what do you do/should I do for back up power...especially with the 18650 where a primary battery is not available.

The ideal for long life of lithium cells is to keep them at storage voltage unless you need them right away. But. 

In practice, I keep many of my cells fully charged and accept that they won't last quite as long as they would if kept discharged.

It takes quite a long time to fully charge an 18650 - anything much under an hour and a half from storage voltage is probably charging them too hard.

So I carry fully charged spares (Usually in another light).

By the time any lithium cell is 4 years old it is likely to be more or less useless no matter how it has been looked after so I don't worry about it.

Think how most laptop battery packs get treated - they are kept on charge pretty much all the time they are being used, and laptops make sure the cells are kept hot too. Which is why they will not usually hold enough charge to be able to boot the laptop after a year or two.

 

The numbers from my light tests are always to be found here.

https://spreadsheets.google.com/ccc?key=0ApkFM37n_QnRdDU5MDNzOURjYllmZHI...

ky70
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Thanks Budgeteer and Don...great stuff.

Chr1s
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Don wrote:
By the time any lithium cell is 4 years old it is likely to be more or less useless no matter how it has been looked after so I don't worry about it.

Think how most laptop battery packs get treated - they are kept on charge pretty much all the time they are being used, and laptops make sure the cells are kept hot too. Which is why they will not usually hold enough charge to be able to boot the laptop after a year or two.

That's going to be a major problem for the electric car to overcome. Having to spend ~$10,000 every four years or so to replace the Li batteries will be a big turn off unless they can make them dirt cheap.

Interesting article here about BYD Co: http://online.wsj.com/article/SB123172034731572313.html

The Tesla Roadster's battery pack uses nearly 7,000 18650 Li-ion cells, weighs 990 pounds, stores 56 kWh of electric energy, and delivers up to 215 kW of electric power: http://www.teslamotors.com/roadster/technology/battery

(Bit off-topic, sorry.)

jekostas
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Underneath my bed pillow at night.

 

Is that bad?

fishinfool
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jekostas wrote:

Underneath my bed pillow at night.

Is that bad?

Not if you're gentle. Embarassed

Don wrote:

"But as I said long ago, you are more likely to be killed by a dead fish dropped by a seagull in the Sahara Desert than by a lithium ion

Haggai
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Chr1s wrote:

That's going to be a major problem for the electric car to overcome. Having to spend ~$10,000 every four years or so to replace the Li batteries will be a big turn off unless they can make them dirt cheap.

There's some work now on lithium-air or silicon-air batteries which could hold much more charge than li-ion per kg, have many more recharge cycles, much longer shelf life and be much safer.

We'll probably see commercial products in about 5 years.

Boaz
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 Like most technologies  what looks promising today is a doorstop by the time it actually hits production .2 years later it's a joke .

I love all the discovery channel ...in the future ..."We will all be riding in cars made of packing peanuts "  <<< damn static electricity  Who needs lithium ion ..??

 

lithium Is probably safer than people are saying on teh forums ..But like a gun it's wise to at least have some sound advice and respect  it fact it's lethal ....My egghead friend a long time ago just raised an eyebrow and started to laugh when i announced I was going to build a charger for lithium ion batteries . The simple statement about home owners  insurance  and fire stuck with me all these years ...

       καὶ τὸ φῶς ἐν τῇ σκοτίᾳ φαίνει καὶ ἡ σκοτία αὐτὸ οὐ κατέλαβεν

                            

       Dc-fix diffuser film  >…  http://budgetlightforum.com/node/42208

didge
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Haggai wrote:

I have two cats and I don't want them to inhale battery smoke when I'm not home... Maybe I should store them in the garage in that metal box. We'll see.

 

Perfect idea for the cats - then you can keep the cells inside the house. Laughing

Cheers

Disclaimer for the humour-challenged:  This is a joke, we have a well loved pet cat (15 yrs old). 

pipopopo
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I charge them in a (glass fibre) fire blanket and store them in the fridge (pretty confined)