Powerwall differences with 32650 Lifepo4 cylindrical cells


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orangezero

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Oct 21, 2017
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I've been testing some prebuilt packs of 32650 lifepo4 cells, and then got a deal on some loose 32650 lifepo4 cells. As I understand it, the lifepo4 cells shouldn't need cell-level fusing as is often recommended for 18650 cells.

My system will be 24v (8s180p). I already have a decent battery powered spot welder. My plan was to spot weld nickel to the batteries and then solder those to the large twisted copper wires like many powerwalls have. Alternatively, I may use flattened copper pipe in some places since I have a decent amount already.

Other than pure nickel strip, what else could I use to connect each cell to the main twisted copper wires?

Despite the fact people can successfully not blow up a battery with the right solder technique, I think I'm going to avoid that. I think that limits me to nickel strips?
 

Korishan

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Jan 7, 2017
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yeah, the lifepo4 cells are far more resilient and less likely to go nuts. And in pretty much all cases, they don't go up in explosive flames. They may vent in flames, but no where near like 18650's do. Those things can go off like a firecracker/rocket

Connecting stranded wire to the nickel strip, the best one I've seen is where another piece of nickel is wrapped over the stranded wire and spot welded to the nickel on the cells. Kinda like a pipe clamp. And then if you want to add some more connectivity, solder that joint. This minimizes how much heat gets into the cells.
Even with LiFePO4 cells, heat is bad. Shortens their life cycles.

You can solder to LiFePO4 cells more successfully than the other lithium chemistries. Heat is bad, but they can withstand it better. So a 2 second application is nothing for them.
All in all, just depends on how you want to build the packs.
 

nbtesh

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Feb 9, 2022
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7
Check out this product on Alibaba App Copper Battery Spot Welding Nickel Plate Flat Connector Tab Sheet Power Pack 21700 Pure Lifepo4 Lithium Ion Cover 18650 Busbar
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hbpowerwall

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Oct 7, 2016
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I edited the above post to the non mobile site :p good find just bought some to play with
 
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