I mean we have been making packs with that pattern for years now and it hasn’t been a problem yet soooooo I guess it’s been fine?
To be fair that is only a 3mm diameter circle, I would think most people weld further apart than that
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yeah nobody is really welding the dead center, just around it
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OH GOD I’ve been welding dead center am I gonna die?
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yup
so no worries 
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How do you know that it hasn’t happened already?
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I wasnt prepared for that response
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Someone asked me that question once. I quickly started chuckling and then I froze…I realized that I didn’t really know.
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If it avoids the center of the bottom of the cell (you can weld anywhere on top) then you’re following the cell manufacturer’s recommendations. Don’t thin the metal at the bottom (with too powerful a weld) and avoid heating the cell up.
You could do a wider spaced (larger) pattern on the bottom to avoid the center even more, if you wanted.
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How about all those people soldering on cells did not get issues with this?
And thx for pointing this out. Guess this is new to many of us.
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I would guess that the solder does not damage the actual metal of the cell can the way spot welding does.
Soldering obviously causes other problems, but not this one specifically.
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But there is way more heat going through this point especially when not experienced people solder on cells (which is often the case I think)
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IMO, it is essentially impossible to solder to a cell without causing damage. It might not be really noticeable right away but it will result in worsening performance and a reduced safety margin over time.
Most people wouldn’t even know that they had damaged the cell unless it caught fire. The loss of performance wouldn’t be blamed on the soldering. They would think it was a ”bad cell”, or how they were using it, or a bad charger. Most wouldn’t think to go back to the beginning and blame the soldering from months ago.
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Yep, pretty much this lol
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Apart from lowering your iron’s temp, minimizing solder thickness and contact time with nickel, what else can be done to reduce heat damage to cells when you’re soldering your series connections?
Use the bend over the cell method and solder the wires to the nickel taps before spot welding the taps to the cells would be the best option.
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What if I’m using the 30mm wide stuff?
Not sure what you mean with it
With wider nickel on your p packs like the 10th photo down from here
I feel like the pack would get cumbersome and hard to work with if you soldered the s connection between each piece of nickel before welding
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if you can, solder then weld.
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