I worked on the battery cells and got the pack assembled. As mentioned, these are A123 Amp20 pouch cells. They measure about 6.25" x 9" plus the connector tabs on top which bring them to about 10" tall. They are roughly a 1/4" thick.
To start, I got the connection tabs all cleaned up and oriented correctly. Then, I used shipping shrink wrap to hold them together.
As you can see, the tabs now need to be connected to create a 4p (4 cells in parallel) battery pack.
To fill the gaps, I chose to use 1/4" thick aluminum bar stock.
Two of the pieces got tapped for an M3 bolt so I can connect a wire to them easily. There are also two end plates made up with holes so it can all be clamped together with threaded rod.
And here is the pack fully assembled. Its quite the solid sturdy thing. For reference, the pack weighs just under 5 lbs.
