FYI: from Red Scholefield's web site:

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SOLDERING

Soldering to Ni-Cds is not a good idea. Try to use the welded tabs and solder to those if at all possible. Soldering to the positive button will have a very high probability of destroying the nylon seal. You just can't get the button hot enough to get a good solder joint without compromising the integrity of the nylon seal ring. This ring is under compression and raising its temperature will allow it to relax and the sealing properties are history.

If you can hold a penny between two fingers long enough to get a good solder joint with #18 stranded wire or braid, then go ahead and solder to your cells, otherwise get cells with solder tabs. Remember, nylon is a good insulator, electrical and thermal. There is no thermal path for the soldering heat to dissipate when heat is applied to the cover button of a cell.

Nylon characteristics:
Nylon has its glass transition at 460°F - 500°F . The maximum use temperature of nylon 6-6 parts is about 300°F. (Note that this is considerably below the glass transition temperature.)

Soldering temperatures are in the 450°F to 650°F range.

I realize this flies in the face of all the electric flight “experts” that assemble their own packs but it is never the less fact.

You have never seen a pack assembled by a cell manufacturer or any other pack manufacturer (outside of the hobby market) where connections are soldered directly to a cell. There is a reason.

C. L. Scholefield
Manager (retired) Battery Design and Application Engineering
General Electric Battery Business Department
Gates Energy Products
Energizer Power Systems
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