18650 Safety for Boosted Board extra pack (flexible)

[NicBok]

After an exhaustive search I cannot determine the best way to protect 18650s against cell chafing (wear through) in a semi-flexible pack.

As a background I'm planning to build (2) separate 36v 10s1p packs comprised of Sanyo NCR18650GAs to extend the range of my electric skateboard. The packs will go underneath the deck and will be exposed to moderate vibration and mild flex (I'm only 140lbs or 63.5kg).
Equipment I already have:
-3/16" or 0.18mm flat tinned copper braid for interconnects between cells (to promote flex)
-60w soldering iron with many tips/flux pen/60/40 ect.
-95mm rubber-like heavy duty heat shrink wrap tube
-iCharger 1010B+
-10 awg wire and bullet connectors
-JST-HX harness
-additional flat-top paper gaskets

First, I'd like to stay away from the top and bottom cell holders that can be found on ebay because I think they will be too stiff and the connection points may just snap.
A few options I thought of with my limited knowledge of pack building:
1. Prime and epoxy individually...by removing the factory shrink wrap, lightly sanding the tubes and using possibly a self-etching primer + paint or just several coats of epoxy primer to make the negative sides impervious to chafing.
2nd option: Buy 0.85mm fiberglass sheet and make dividers in-between each cell, then lightly hot glue at contact point with understanding the the glue will break after pack installation but will create another barrier. Fish paper electric insulation could also be used.

I know it's my first post here but this site seems to be the most respected place for building packs. I'd gladly post pics prior to wrapping for final safety check. Thank you for your help!

 

[dogman dan]

If you mean preventing each cells shrink from chafing through on adjacent cells, I'd first experiment with adding another layer of shrink. you can get large shrink cheap at harbor freight usually. Then just glue the whole thing together, using something a bit stronger than typical hot glue.

The very last thing I'd want, is to remove original shrink wrap.

If you mean the usual problem of chafing between the tab and the negative part of the can on the positive end, cut cardboard gaskets to cover the negative part of the can, and place them under the tab on the positive ends. Doesn't sound like you are using tabs, but do be aware of a bare chunk of + wire potentially contacting the edge of a can.

 

[fechter]

If the interconnects are made with copper braid that will take care of any flex on the wires.

If you lay out the cells with a little space between them, you could probably just fill in the gaps with silicone glue. Once one side cures, flip it over and do the other side so you have a solid silicone divider between cells. Having some kind of temporary holder to keep the cells in place while gluing will help.
Once both sides are glued, it should be quite flexible. You could then heat shrink over the whole thing or wrap it with something to provide protection to the outside surfaces.

 

[NicBok]

Thanks for the responses.

The very last thing I'd want, is to remove original shrink wrap.

I'm aware doing this can be dangerous but if I remove the wrap to spray primer on the tubes then re-wrap, wouldn't that add a layer of safety? I would do so at a low SOC%. I know it sounds like overkill but these will be ~120 W/h packs and I'd like to bring them with me while traveling.

If you lay out the cells with a little space between them, you could probably just fill in the gaps with silicone glue.

I like the suggestion. Maybe in-between I'll also add some adhesive back dielectric paper.

 

[dogman dan]

Assuming its still 2p or 3p or whatever, I'd make it no flex within each set of paralleled cells. then you could shrink each section, then use flexy glue like silicone to allow some give between each section.

I still think removing the original shrink is a pretty poor plan.

 

[Punx0r]

What Fetcher said^^^