Connecting Racing Pouch Cells- A Question I've yet to answer

[bg10389]

Hello, I have been trying to answer a question for a while now, but i have yet to figure out how to effectively do this.

I am part of a collegiate competition team specializing in electric go-karts and autonomous go karts. Years ago, we bought a lot of racing LiPo cells from Melasta for our electric karts. The problem is the way they were being connected kind of sucks, and I know there has to be a better way. they originally used through bolts, holes in the tabs, and thick wall copper pipe as spacers for the battery connections. While it works, its super bulky and annoying and I hate it.

I've tried to spot weld them, but I think my equipment is just not up to par. For reference, I built a spot welder with 3x Spim08hp cells in series, and a 2000a spot welder board as shown below. I should be getting enough current to weld .2 or .3mm nickel strip to these, or even possibly to weld the cell tabs together in series, but it seems they just don't want to be welded. I don't know if it's a current issue, but they just wont. I can get nickel strip to stick juust barely, but once I pull it comes right off. I believe the cells have nickel plated copper tabs. They take solder pretty well, which lets me put BMS wires on them but not much else..

Has anyone been able to weld this kind of battery before, or have better ways of connecting them?

Thanks for the help.

 

[Portugaline]

Hello,

If you say the tabs are nickel plated cooper, just solder together.

If they aren’t nickel plated ( usually they are copper/ aluminum ) you can use aluminum flux but is a messy job, or you can join the together mechanical like you did before.

Spotweld this tabs with your machine I think will not be possible.

 

[peadar]

Hello, I have been trying to answer a question for a while now, but i have yet to figure out how to effectively do this.

I am part of a collegiate competition team specializing in electric go-karts and autonomous go karts. Years ago, we bought a lot of racing LiPo cells from Melasta for our electric karts. The problem is the way they were being connected kind of sucks, and I know there has to be a better way. they originally used through bolts, holes in the tabs, and thick wall copper pipe as spacers for the battery connections. While it works, its super bulky and annoying and I hate it.

I've tried to spot weld them, but I think my equipment is just not up to par. For reference, I built a spot welder with 3x Spim08hp cells in series, and a 2000a spot welder board as shown below. I should be getting enough current to weld .2 or .3mm nickel strip to these, or even possibly to weld the cell tabs together in series, but it seems they just don't want to be welded. I don't know if it's a current issue, but they just wont. I can get nickel strip to stick juust barely, but once I pull it comes right off. I believe the cells have nickel plated copper tabs. They take solder pretty well, which lets me put BMS wires on them but not much else..

Has anyone been able to weld this kind of battery before, or have better ways of connecting them?

Thanks for the help.

Do you have pictures of cell bolted together? I am building 24s kokam pack, looking for ideas

 

[series_hybrid]

If the tabs are touching each other (Negative tab on one cell touching the positive tab on the next cell), then the clamping methods don't need to be conductive. This also means if you use a steel bar for rigidity, they can be threaded, instead of having a nut-and-bolt to clamp everything down.

Here is a discussion with a few pics.

Index of flat pouch cell connection methods

There doesn't seem to be a definitive DIY solution to connecting the tabs on pouch cells, but quite a few ideas. I come across variations when I read about a pack build, so I'd like to collect the types here as a reference and a place of discussion. Today I just found out about the "Termifoil"...

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