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Inside a LiPo Battery

Discussion in 'Renewable Energy' started by tytower, Jan 29, 2011.

  1. tytower

    tytower Banned

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    This is a 3S LiPo which would not recharge . On investigation one cell was shorted out. I removed that cell and cut it open for a look.

    Now they are in series and the top connector is soldered solidly .Pos to neg of next cell.
    Heavy power out leads are at the ends. the red charging wire connects to pos ,the next small black charging wire is to neg of same cell and pos of cell 2, the next small black is to neg of cell 2 and pos cell 3 and the last small black is to the negative of cell 3

    So by putting in small cut off wire pieces you can read the voltage of each cell with a multimeter. Obvious for some but I initially had no idea how those charging wires were set up

    The flat cell I cut open to see a lot of aluminium foil and a black paste layer set up like a capacitor . I tried to ignite the paste but could not . I tried to burn the cell itself with a gas torch to no avail. I crinkled it and dropped it and bent it but it still did not seem to want to catch fire for me !

    The heavy terminal material going into the cell was remarkable ,like a metalised plastic strip 1/4 inch or so wide and flat.

    I suppose it might have to be fully charged to ignite hey?
     

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    Last edited: Jan 29, 2011
  2. Reloadron

    Reloadron Well-Known Member Most Helpful Member

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    Why don't you do a little reading about the batteries and gain some understanding as to why they "explode". Your little science experiment was stupid to say the least, not to mention dangerous. The "explosion" of LiPO batteries is a result of mass pressure release. Ever wonder while you played with a torch what toxic fumes were being released? So how do you plan to now dispose of your little toxic waste pile?

    Ron
     
  3. tytower

    tytower Banned

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    66views and then...
    Theres always a "wowser" in the wings
    A "do gooder" thats going to save the world
    Pity they don't ever achieve anything , they are too busy telling others what to do or not do.

    I wondered if I should tell all "wowsers" to stay away when I posted but decided better not to mention them lest I pull them in . None of them can resist being a pathetic impersonation of a policeman. Perhaps you should go enlist? Perhaps you were unsuccessful ?

    You need not worry ! When I turn round there will be some Government ******* waiting there to tell me what I can and can't do anyway so I don't need your input.

    On the toxic waste problem , what will you do with your expired LiPo's? What will others do ? Mine have served a twofold purpose . Practical application and a teaching aid.

    And you in the States telling us about waste - what a joke. America is the most wasteful pollutant country in the world at the moment with India and China rapidly catching up . You made them thar LiPo batteries in the States first.
    What are you guys doing about it Dude?
     
    Last edited: Jan 30, 2011
  4. dave

    Dave New Member

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  5. Reloadron

    Reloadron Well-Known Member Most Helpful Member

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    Look, personally I don't care if you want to take batteries apart. Taking things apart is a good way to learn. I am also saying that it would have been wise to study up a little on the battery you plan to take apart prior to doing it and gain an understanding of their construction. I also said that in my opinion what you did was not a real bright move. That was it. So save your issues. If you want to do stupid things, hey, cool with me it is your business. I just would not want to see other forum members, those just learning, do stupid things. That's all. No governments involved.

    Ron
     
  6. audioguru

    audioguru Well-Known Member Most Helpful Member

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    Politics aside, I understand that the Lithium salts (ions) in a Li-Po battery convert into metallic Lithium when the battery is over-charged or over-discharged. Lithium is very active and catches on fire easily. Maybe water on metallic Lithium causes a violent reaction.
     
  7. Birdman Adam

    Birdman Adam New Member

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    It does! A good experiment is to buy some Energizer Lithium batteries, open them up. You will find a rolled up sheet of lithium metal. Be quick and put it into a bottle of mineral oil because it oxidizes quick with the air otherwise. Snip off a bit and stick it in some water. Small amount will fizz and bubble, bigger amounts will burn and possibly have a small explosion. Were gloves always, and do this outside!!!
     
    Last edited: Jan 30, 2011
  8. dknguyen

    dknguyen Well-Known Member

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    Pollution, policemen, do gooders and explosions...I don't see the connection.

    I hope you did it outside at least. And the cells don't ignite so much as they explode (at least when sealed enough to build up pressure ) which makes rather careless to take a torch to it unless you had a way to be pretty far away at the same time.

    It's possible that the cell was discharged enough that being shorted out did not cause it to ignite while completly emptying it leaving little energy left. After all, standard Lipo disposal is to completely drain the LiPo over a long period of time at low power before disposing.
     
    Last edited: Jan 30, 2011
  9. tytower

    tytower Banned

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    Hmm Ho Hum ..
    The reason for the pictures is that there is no need to do this for our forum members.
    I've done it and they can read what's in them and see what's in them with pictures .

    On the pollution side in fact what was a 3 cell pack has now been converted to a working 2 cell pack so rather than disposing of my battery pack I have in fact recycled it !! Only the damaged cell had to be disposed of . Interesting on the energiser lithium cells and bits of lithium , must try that . I will remember to dispose of the water properly if I can just find some way to inject it into my nasty neighbour .

    Sounds a lot like metalic magnesium which we used to do science experiments with . That was always fun to watch. Very violent reaction.
     
  10. tytower

    tytower Banned

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    dknguyen - Your signature line is a puzzle? Is there a hidden meaning there?
     
  11. dknguyen

    dknguyen Well-Known Member

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    No, it means what it says- more people spell ridiculous the same wrong way than they do the right way.
     
    Last edited: Feb 23, 2011
  12. tytower

    tytower Banned

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  13. Blueteeth

    Blueteeth Well-Known Member

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    Perhaps I'm missing something here - I just don' see the point. You took apart a LiPo battery pack to....see how to charge it? or perhaps what protection circuitry was in there? You don't need to burn things to see that... Its pretty obvious why lithium based batteries catch fire, and why many batteries of different chemistries can explode. I'm all for taking things apart and tickering around - just don't know why you posted it without providing anything in the way of useful information.. Am I the only one? I am half asleep..
     
  14. cowboybob

    cowboybob Well-Known Member Most Helpful Member

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    I remember my first "what's in a battery" experiment. One of those big, tall, fat 1.5V types. Guess I was about 7 or 8.

    Big ole carbon rod. Loads of black, wet crumbly stuff and a thin lead sheet on the outside.

    DID NOT know anything about them. Didn't have no Google.

    DID find out later, as evidenced by my really ruined jeans (and my burned little fingers), all about acid.

    A plethora of info.

    Heard a LOT from my Mom. More info.

    So, Caloundra. Goggled it and it seems like a really nice spot.

    Anyway, no harm, no foul. Brave of you, though, to post the whole affair.
     
  15. audioguru

    audioguru Well-Known Member Most Helpful Member

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    A number 6 dry cell to heat the glow plug on a smoky and noisy model airplane engine?
    Been there, done that.
     
  16. cowboybob

    cowboybob Well-Known Member Most Helpful Member

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    AND oily*.

    A little Cox .049

    *(Something else my Mom pointed out to me.)
     
  17. audioguru

    audioguru Well-Known Member Most Helpful Member

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    I had a few Cox .049 engines.
    I made a free flight Cub airplane with a pendulum connected to its elevator. When the nose went up then the elevator went down. When the nose went down then the elevator went up. It flew about 10 feet above the ground until it ran out of fuel or went in a tree. It had a Cox .020 engine.

    I also had a Cox .010 engine in a very small triplane with control lines.

    Now I fly radio controlled electric powered model airplanes.
     
  18. cowboybob

    cowboybob Well-Known Member Most Helpful Member

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    Me too. Although I prefer the gas ones.

    I've still got my .049 and have added over the years a Cox .020, a .010 and a .079. Also digital RC and a lot of pieces parts.

    I do balsa almost exclusively and a lot of control surface design experimentation.

    Sad to say though, I've never been able to keep an airplane aloft for more that a few minutes. Imagine that, given the previous sentence.

    So I had to decide that what I was good at was crashing them in ever increasingly spectacular fashions.

    And that the real fun was is repairing them...
     
    Last edited: Feb 14, 2012
  19. audioguru

    audioguru Well-Known Member Most Helpful Member

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    This thread is about Li-Po rechargeable batteries.
    Some of mine are 1 cell, 125mAh with a max current of 25C (3.125A).
    Others are 1 cell, 160mAh with a max current of 25C (4A).
    Another battery is 2 cells, 180mAh and I don't know its max current but it is a lot.

    My first RC electric airplane (Parkzone J3 Cub) weighs 0.85 oz (25 grams) with battery and flies for about 10 to 15 minutes with a 125mAh battery or forever if caught in a thermal. With a 160mAh battery it flies for a long time (I didn't measure it).
    When the battery voltage runs down then the electronics turns off the motor but there is still enough battery power to steer while gliding.
     
  20. cowboybob

    cowboybob Well-Known Member Most Helpful Member

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    Right. Sorry.

    I do have some lithium battery powered planes.

    My biggest beef is their short flight times. The battery/control/motor systems are impressive though.

    I know they'll get better.
     
  21. audioguru

    audioguru Well-Known Member Most Helpful Member

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    Then the batteries might not be up to date.
    Modern Lithium rechargeable batteries are much bettert than "old" batteries that are only 2 years old.
     

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