3D printed copper compression battery

Hummina Shadeeba · Dec 19, 2017

how do you think it will go?! I will stack them and 6 long 12s. 4p. I can add more copper foil and plan to but now it's at a single thick .5mm with the dimples pressed in on an abs printed press. i'll go thinner on top since info on ES says it contours better for better connection.

how to get compression with them I like this tape most. If you wrap it on your finger with 5 turns pulling it on at a pretty light pressure, you will feel like you are going to explode and that's the testing so far. or maybe could use rubber bands and that was the original plan.

to be more scientific it'd be nice to figure how much pressure is put on the cells and how it decreases through use. if you have an idea? Maybe grin pressure sensors?

its super minimalist.
I'll add some balance lines from the exposed connection.

flippy · Dec 20, 2017

i see this going with a ball of flame when the tape loses its elasticity.

Hummina Shadeeba · Dec 20, 2017

The tape might not be the best material but I’ve got some super resilient rubber bands on route. I believe a band could for sure keep compression for a very long time. After so many miles with the bands I can take one off and compare its strength to a new one to see

GalFisk · Dec 22, 2017

Both tape and rubber (natural an silicone) ages with heat and time.
Scotch 8884 is made for securing objects during shipping, so no regard has been taken to long term stability.

The best you can do is to do this reasarch yourself.
Get the tape and the rubber bands you want to use, and find the highest and lowest temperatures the materials will experience in your battery.
Stretch it and store it at either extreme. Cycle some between the both extremes. See how well the elasticity lasts.
If it lasts well for many weeks, build the battery and disassemble it periodically to inspect the elastic.
Protect the elastic from abrasion in the battery case. Stretched elastic is sensitive to this.

Buk___ · Dec 22, 2017

Hummina Shadeeba said:
The tape might not be the best material but I’ve got some super resilient rubber bands on route. I believe a band could for sure keep compression for a very long time. After so many miles with the bands I can take one off and compare its strength to a new one to see

If you try rubber, lubricate it lightly, but thoroughly, inside and out with something like silicone grease. Excluding the air will make it last longer.

Then wrap it over in shrink wrap. It'll protect it from abrasion and take some of the load off.

Hummina Shadeeba · Dec 22, 2017

I think cooking the bands under shrink wrap could be possibly ruinous with the heat. epdm rubber bands seem the most robust and will use those. Each of theses packs of 4 rubber banded cells will probably be strapped down with Velcro by their center.

they use 17mm copper strip .5mm thick ( 8.5mm2) while 10awg wire is (5.3mm2) so assume good enough with a good connection.

printing them with bigger contacts as they're a small 4mm in the design above.

getting color-changing-with-temp filament for these parts.

Buk___ · Dec 22, 2017

Hummina Shadeeba said:
I think cooking the bands under shrink wrap could be possibly ruinous with the heat.

If you are generating enough heat in your batteries to damage the rubber; then you have much greater problems than the rubber!

Hummina Shadeeba · Dec 23, 2017

I'm saying if youre using shrink wrap and a heat gun to get it on that's a very high heat which the rubber bands wont like

Buk___ · Dec 23, 2017

Hummina Shadeeba said:
I'm saying if youre using shrink wrap and a heat gun to get it on that's a very high heat which the rubber bands wont like

It doesn't take much heat, and very little would reach the rubber.

And if the bands are silicone rubber, then they will easily withstand it. My wife uses silicone rubber spatula for frying and silcone rubber molds for baking. It's good to 300°C and upto 1100% elongation before breaking.

Hummina Shadeeba · Dec 23, 2017

good idea

dustNbone · Dec 24, 2017

I'd look into electrical splice tape, like Scotch 23 or the like. It's designed for a wide temperature range, somewhat elastic, and thermally conductive. You might check you local electrical supplier and see what they have to say.

Rubber bands are probably not going to hold up long term, though a coating of something to keep the air off them as suggested above will help substantially.

999zip999 · Dec 24, 2017

I have a vacuum caster and I put a 1200 degree iron flask on the silicone gasket. I just don't understand how that silicone gasket can withstand the Heat used it 200 times. Silicone rubber band sounds good to me if going the rubber band route.
Got to get the right silicone.

dustNbone · Dec 24, 2017

Yeah pure silicon melts at something like 1400C, but it's also extremely brittle, I'm really not sure what the composition of things like silicon baking sheets and wire insulation is but it sure can take the heat.

Buk___ · Dec 24, 2017

Hummina Shadeeba said:
good idea

Another [strike]one[/strike] two. Idea that is; I'll leave it to to decide if [strike]it's a[/strike] they are good.

1) Butyl rubber is surprisingly resistant to UV, ozone, and heat, so ages well if oxidising agent -- alcohol, petrol, some oils etc. -- are absent .

Think sections of circa 2" suitable inner tube.

2) Self-amalgamating silicone tape. (Other brands and suppliers are available )

This stuff is tough! 16 years ago I used it (as a temporary measure) to repair a leaking gutter/downpipe joint. I check it every year when I clean my gutters, and despite direct sunlight in summer and sub-zero temperatures in winter, it is still waterproof, and still flexible.

And, it exerts pressure. Wrap a piece around on itself around your finger, with just enough tension to make it adhere, and your fingertip will turn blue in a minute or so.

Hummina Shadeeba · Dec 25, 2017

I don't think heat will be a danger with any rubber:
http://www.jjshort.com/Rubber-Properties.php
I've got all these bands coming from amazon and now like the inner tubes idea best. crafty. I imagine cheaper. Faraday discovered Isobutylene or butyl.
I don't think a tape would be as good because it sticks to the cell reducing compression and its compression is only as good as the tiny amount of material between the cell and plastic part and the rest of the tape is stuck. Being able to take the bands off to see if they've lost stength after long-term use is a super safety feature.

I've got pretty thin 5mil copper coming and hoping it's more flexible than the 10 and 20 i have.

Hummina Shadeeba · Feb 14, 2018

liked this design last before getting a spot welder. with the bands it wouldn't fit the skate deck I want to use. I like the guards allowing a loop of copper to come up and I imagine relieve physical strain.

3D printed copper compression battery

Hummina Shadeeba

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flippy

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GalFisk

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Buk___

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Hummina Shadeeba

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Hummina Shadeeba

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Buk___

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Hummina Shadeeba

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dustNbone

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999zip999

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Hummina Shadeeba

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Hummina Shadeeba

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