Making my own Button Tops to weld onto Flat Top cells.

[walterwitt]

A local Mesh Radio Enthusiast group started buying cells from me, and one of the big requests they have is for button top cells. But I don't think they're worth 2-3x the cost, so I looked into spot welding my own button tops on my existing cells. @BlueSwordM then told me that it's be great if they where made of pure Nickel instead of Steel for better conductivity, which he later revealed was actually @BatteryMooch 's Idea. So after not finding any satisfactory results on AliExpress, and mostly not wanting to wait so long, I came up with a 3D printed Jig to turn 6mm Nickel Strip into professional looking button tops. Here's some pictures






It uses 4mm dowel pins that press the nickel strip into a PETG die. It has 4 slots, but the 4th I use as an indexing point so it really just punches 3 at a time, but I end up with quite consistent 9mm spaced 2mm tall button tops. I then cut them out as shown above, put them in a little 3D printed centering Jig, and spot weld them to some EVE 35Vs



After all that to make them clean enough to sell, I hole punch some Fish Paper, stick it on, trim to size then heat shrink.

I only had black heat shrink lol.

But yeah, feel free to ask questions, I'm better at sharing pics than thoughts as you can see.

 

[walterwitt]

If your in Canada, and would like to buy some, I have them up for sale now at MPandW.ca

 

[harrisonpatm]

Neat project!

 

[BatteryMooch]

A local Mesh Radio Enthusiast group started buying cells from me, and one of the big requests they have is for button top cells. But I don't think they're worth 2-3x the cost, so I looked into spot welding my own button tops on my existing cells.

Those came out great! Looks so much easier to do with “soft” nickel rather than steel too.

The only thing that triggers my OCD is that the corners of the button tops are sticking out a lot and increasing the chance of a short-circuit, especially if one snaps loose.

It’s a PITA to trim them but maybe a circular or arced punch could make quick work of it?

 

[walterwitt]

Those came out great! Looks so much easier to do with “soft” nickel rather than steel too.

The only thing that triggers my OCD is that the corners of the button tops are sticking out a lot and increasing the chance of a short-circuit, especially if one snaps loose.

It’s a PITA to trim them but maybe a circular or arced punch could make quick work of it?

Yeah, that's part of the reason why I'm triple welding them, to make extra sure they don't come loose. But yeah, I am still looking into ways to improve, I just didn't have a more consistent way of cutting them to size other than by hand. I'll look into some punch set options that don't interfere with the center button top. Maybe another 3D printed jig to position it lol.