Battery pack welding

[Jeremy]

Not really a mainstream topic, but I know that a few on here have had a go at making up their own battery packs in the past.

Faced with needing to weld up 64, 10 ah, LiFePO4 cells, I took the plunge and built a capacitive discharge spot welder. I've just finished the initial testing and it seems to work pretty well. Rather than clog this forum up with detailed techie stuff, here's a link to the end of the thread on this topic, including several pictures of my machine: Endless-sphere.com • View topic - Build your own CD battery tab welder for about $100.00+-

My pics are well down that page.

Jeremy

 

[flecc]

I echo nemo Jeremy, a very nice job. It's almost sad that it will be laying idle for much of the time when it's so obviously capable of production work. Maybe you could lease it to someone setting up in recelling?
.

 

[Jeremy]

Thanks Flecc.

I know that Nick (Tiberius) wants to borrow it for his new project, so my guess is that he may be the first to "re-cycle" it!

I could have made it a bit simpler, by doing away with the pillar arrangement and using hand-held electrodes, as others have done, but I thought that I may as well do the job properly, so that I get consistently good welds on my new pack. It will have to do quite a lot of welds, just for the one pack. I'm connecting up 64 cells, which need about 10 welds each, 5 pairs of welds at each end of each cell.

Jeremy

 

[flecc]

Well that's certainly a very good workload for it to start with!
.

 

[Tiberius]

Thanks Flecc.

I know that Nick (Tiberius) wants to borrow it for his new project, so my guess is that he may be the first to "re-cycle" it!

Jeremy

Yes, I've got 24 LiFePO4 cells to weld up. The manufacturers did weld them up for me, but into the wrong configuration, so I'm talking very nicely to Jeremy.

Nick

 

[Jeremy]

No problem, Nick, you're welcome to borrow it.

To get a neat job you really need to make a box to hold the cells in the right position. I'm welding my pack up in sub-units of three packs of four, with each pack of four arranged in a square, as yours currently are.

I'm part way through making a wooden box to hold 12 cells at a time and may opt to fit guide rails to the welder base to make lining the welds up a bit easier (just for neatness, really). I'll post some pictures when I'm done, to give you an idea of how it works.

Jeremy

 

[Tiberius]

Does your jig have a feature to hold the nickel strips in place? That would make it look even neater.

I think I'll make up a jig for mine, too. I'm going for 12V sub packs and I still need to decide how to assemble the sub packs.

Nick

 

[Jeremy]

I wasn't planning on making it hold the strips, Nick. I think it'll be easy enough to position each strip, using the pressure of the electrodes to hold it in place and allow small adjustments, until the first weld is complete. After that, the strip will be held by the first weld.

The jig is just a simple, shallow, wooden box, open at one end, rather like a deep tray.

Jeremy