Making your own lithium-ion batteries

You can make your own lithium-ion batteries if you have a source for individual cells and a control board to match your desired voltage levels. [Bill Porter] put together a quick tutorial where he makes a 14.4V 2.2 AH battery for about $10. He picked up a set of cable-modem backup batteries (used to make sure your bundled phone service doesn’t quit working when the power goes out) and tore out the cells. After reconfiguring the connections and swapping out the controller board the original 8V battery is now 14V.┬áThis doesn’t take into account any problems with battery life and charge leveling, but that’s a whole different tutorial waiting to happen.

If this type of battery hack is child’s play to you, take a look at a more involved lithium iron phosphate build.

22 thoughts on “Making your own lithium-ion batteries

  1. Make your own battery packs that is not your own batteries. Each of those cells is a battery vs a multi cell battery like in your car.

  2. I think the article title is a bit misleading, maybe “Making your own lithium-ion battery packs” since I see no construction of the battery itself.
    not that this isn’t cool, it is! just sayin’ I see no construction of a battery, just assembling a battery pack

  3. “Make your own battery packs that is not your own batteries. Each of those cells is a battery vs a multi cell battery like in your car.”

    You seem to be confused about the English language (though, it’s understandable since we Americans do seem to use the term “battery” to incorrectly refer to cells). The, actual, definition of the word “battery” is a number of cells combined into one unit. It’s derived from the military term for a group of artillery. Technically speaking, (the best kind of speaking) a “battery pack” would be a group of these groups of cells.

  4. You should make a belt that will hold a bunch of those around your waist. Maybe a quick release button that you hold in your hand with a wire going back to the belt. Test it out in a crowded public place.

  5. “Hero of the day”? I hope that was sarcasm.

    “Battery” properly refers to both the pack and the individually packaged cells that go into it. This is not a American foible – the OED specifically mentions such devices “whether of one cell or more”. More recent (and less formal) definitions observe that a battery comprises one or more cells within a container. Still, it can be useful (as well as correct) to refer to the individual cell that make up the pack if the distinction is not clear.

    Now here’s the disclaimer that HAD failed to mention: Li-ion batteries are high energy devices that will release their energy in an uncontrolled manner (e.g. burst into flames) when abused. Li-ion batteries do not tolerate over-charge or -discharge, and they require specific charging strategies. Hopefully, you will find modern cells with built in protection mechanisms that permanently disconnect the battery, rather than exploding, if you screw up. The old DIY advice was to charge your homebrew li-ion pack in a safe container (e.g. tin can) on a heat tolerant surface like a concrete driveway. You have been warned.

  6. The PCB you see in the picture acts as the safety, it will disconnect the pack if it is shorted, and it also balances the cells during charge.

  7. Li-Ion batteries can be ‘unsafe’ and have the potential for causing a lot of damage, however when used with a safety circuit that risk should drop to almost zero.

    A good safety circuit will monitor pack temp, individual cell voltages, pack current, etc and instruct the smart charger what voltage/current to apply. Under adverse conditions it will either temporally or permanently disable charge/discharge.

    ‘Good’ Cells also come with a pressure venting system which further protects the individual cells.

    Bottom line: if you use a smart charger and correctly programmed safety circuit there should be little risk. If you deliberatly set out to damage a pack, you can make a big mess….

  8. My first impression of this article after reading the headline was that you were going to show how to make the individual cells. That would be very interesting.

  9. People often mention good safety circuits and chips that can monitor the charge and discharge.

    Are there any guides on building the circuit or the chips one may use? An application where the battery pack can be integrated and charged within the device (auto switch charging or running via ac adapter) would be really neat.

    The max1555 sounds pretty close to that but its hard to find and will only charge a single cell.

  10. When I saw the article title I was going to come post a warning about keeping Lithium around. These days you can get an intent to manufacture meth charge having that and cold medicine in the same building. I made the same cell vs. Battery syntax error as someone else though so now I don’t feel so bad…

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