Homemade Flat Li-ion Battery Adapter


Introduction: Homemade Flat Li-ion Battery Adapter

As having an old cracked-screen smartphone laying around and also, having a project in progress with the necessity of a Li-ion battery, I thought that's a good idea to make some sort of adapter to make use of that battery.


Copper covered board for PCB manufacturing

Soldering wire

Soldering paste

Soldering iron or station

Two pins (like those from arduino)

Battery from an old phone

Something to cut (I've used a Dremel like cutter)

Sandpaper to get everything even

Sharpie or a pencil to trace where to cut

Ruler to make straight lines :D

Step 1: Cutting Everything

According to your battery size, use the battery as a guide and trace some lines with the pencil or sharpie. Then, use a ruler to trace straight lines and surround the rectangle made using battery dimensions, with another bigger rectangle. Between those two rectangles you have to maintain at least the measurements of the height of the li-ion battery. Then cut everything and don't forget to use the sandpaper if you cannot deliver a streight cutting like myself.

Step 2: Soldering

After sanding all the edges, use something to handle the sides of the box and start soldering in points like I did in the first photo. If you want to check the perpendicularity of the soldered piece, use the battery as a template and ajust the angle if it's needed.

Step 3: The Finished Product

After finishing the box, use the dremel to score the copper coating from where battery terminals are going to be. This step is very important because you have to provide a good separation of the box terminals to avoid short circuit. Then drill some holes and solder the pins used for charging and connecting to other devices.

Step 4: Charging Test

After checking the connections of the box with multimeter, connect the battery inside its new adapter to a li-ion charger module. And that's it... :D Aaaaand...don't forget to vote this project on one of the contests! Thanks! Cheers!



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    why not just solder the wires on after all you will be soldering to the protection circuit and not the battery terminals direct

    3 replies

    because you can damage the protection circuit and it's pretty dangerous to play with intense heat around lithium batteries...

    well considering i have a pack of 60 cells 18650 soldered together with solar tabbing wire and put in series and have soldered many protection circuits with out any issue and i know alot of people made ebikes and the fact the pcb is soldered to the battery terminals i feel people over exagerate on how much heat it takes to damage things a 30watt soldering orin can solder li-ion cells and pcb's with out any issue

    ok. but what if you want to swap the cell very fast?...I guess this is the main purpose of this project. Is the battery soldered inside phones?...No it's not. And it will never be soldered.