Soldering A123 Cells

Starting a new project, I would love to put some of the donor A123 cells to use. The studio's spot welder is nice, but we are currently too inexperienced to do a good job.

Unless you want crater packs.

Given the rather complex pack geometry, that leaves really only one option: soldering.

The anode and cathode of A123 cells are not made of the same materiel. The cathode appears to be made of nickel and the anode is made of aluminum. From experience you may know, one is easy to solder to and the other is not. 

If you dont have a huge iron, you'll have to resort to other creative methods. Charles Guan was visiting that weekend and devised a interestingly ballsy method of soldering to the aluminum end of the cell.

DOUBLE IRON METHOD

Materials Required

• Two Soldering Stations. Chisel tips preferred (surface area)
• Rosin Core Flux pen
• Solder (of course)
• Rough Sandpaper. 100-200 grit works fine
• Helping Hands or some Cell Holder (advised but not required)

step 1: heat two soldering stations to very very very hot.

step 2: use the sandpaper to rough up the surface.

step 3: place one iron on the cell end and feed solder onto the surface until a reasonable glob forms. The glob should have the appearance of having adhered to the surface (whilst we know it isn't enough).

step 4: use the flux pen to paint the entire cell surface. be generous in covering the solder glob and adjacent areas.

step 5: take both irons and heat the solder glob at once. Wiggle (or jiggle f you feel) the double iron assembly about the surface of the cell. The solder should begin to melt instantly and flow across the surfaces where flux was applied. 

step 6: repeat for X number of cells.

Here is a video of the last step.

Enjoy!