Modular 18650 Battery Holder

I recently acquired a couple hundred 18650 lithium ion batteries and I needed a way to mount them for a couple different projects I’m prototyping.

Design requirements:
-No spot welding
-Minimal material needed for print
-Fast, easy print (preferably no supports needed)
-Single object (can be used for + or – side)
-Multiple solder points between adjacent cells for high and even current flow
-Small airgap between batteries for better cooling
-Very modular (can be used in either series or parallel configurations)
-No fine features (I like printing with large nozzles)
-Semi-permanent
-No costly hardware

I did not want to buy any springs because of the quantity needed. A Keystone 209 spring may only be 20 cents, but 400 of them would be more than I paid for all of my batteries. Instead I am using nickel tape (ebay: 7Meters long, 8mm wide, $2.29 total).
For parallel configurations I align all batteries in the same direction and weave 14cm of nickel tape through all of t