IdleMind
100 W
A while ago there were some threads discussing solderless 18650 pack construction. This caught my interest enough that I wanted to give it a try. I am currently using a pack made of 14 HK 4s bricks (8s7p) and it works great, so I don't have an immediate need for a whole new pack. So to start with I am making a 1s35p pack to use as a booster for my current 8s Lipo pack which will bring it up to 9s.
The outer case is made from 2 inch PVC pipe. The cells are stacked 5 high and there are 7 cells per layer all connected in parallel. At one end there are 7 springs to compress each string of cells. Between each group of 7 cells there is a flexible copper plate to make electrical contact. The copper plate is .008 inch thick.
The pipe's ID is a bit too small to accept the 7 cells so first I turned the OD smaller in a lathe to make it more flexible, then I slit it lengthwise so it can be spread open enough to insert the cells. Here's how it looks with a group of cells inserted in one end, you can see how the split pipe tightly holds the cells.
It's held together with 2 end caps and 3 tie rods made of 10-24 threaded rod partly covered with shrink tube. Seven springs tension the rows of cells. There are 6 contact plates, the positive plates have raised bumps to assure they do not make contact with the cell case. Each contact plate has a 4mm female bullet connector for attachment to the wire harness. Here's a photo of the parts.
Here's a photo of the assembly and the assembly after taping.
These parts could be rearranged to make a 5s7p pack, and two packs put together for 10s7p.
I'm working on getting it mounted in my bikes trunk and will also be discharge testing it.
The outer case is made from 2 inch PVC pipe. The cells are stacked 5 high and there are 7 cells per layer all connected in parallel. At one end there are 7 springs to compress each string of cells. Between each group of 7 cells there is a flexible copper plate to make electrical contact. The copper plate is .008 inch thick.
The pipe's ID is a bit too small to accept the 7 cells so first I turned the OD smaller in a lathe to make it more flexible, then I slit it lengthwise so it can be spread open enough to insert the cells. Here's how it looks with a group of cells inserted in one end, you can see how the split pipe tightly holds the cells.
It's held together with 2 end caps and 3 tie rods made of 10-24 threaded rod partly covered with shrink tube. Seven springs tension the rows of cells. There are 6 contact plates, the positive plates have raised bumps to assure they do not make contact with the cell case. Each contact plate has a 4mm female bullet connector for attachment to the wire harness. Here's a photo of the parts.
Here's a photo of the assembly and the assembly after taping.
These parts could be rearranged to make a 5s7p pack, and two packs put together for 10s7p.
I'm working on getting it mounted in my bikes trunk and will also be discharge testing it.