What u think of this?! Tape connections. And potting

https://imgur.com/gallery/FhYF1Ec

* updating the title hoping to grab the same folks at least.

What do you plan to use them for ?

Better be stationary.

Or fully pot the lot, but still there will develop higher-resistance air gaps in time.

unless 3M has created super conductive VHB tape or something?

have you tried copper slug tape?



https://www.amazon.ca/DanziX-Conductive-Shielding-Repellent-Electrical/dp/B07917LYX5/ref=asc_df_B07917LYX5/?tag=bingshopdesk-20&linkCode=df0&hvadid=&hvpos=&hvnetw=o&hvrand=&hvpone=&hvptwo=&hvqmt=e&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=&hvtargid=pla-4584001424157084&psc=1

im not a spot welder but I was wondering if you can spot weld through it. battery/tape/nickelstrip

I tried the adhesive backed copper tape and it’s very bad at conducting through the adhesive. Welding it it explodes.

This will be far from a stationary battery. It’s designed to flex on a relatively stiff longboard. In my mind when it sits in the box on bottom of the board, cells down with Velcro holding the cells, and that’s the only contact the battery has, just the Velcro to the cells..it’s good. I don’t know about the tape connections surviving this environment long term but the batteries I’ve made like this, welded, are still working.

If the resistance of the connections doesn’t increase in use, as I imagine they will, it would be great to see.


So far I haven’t got one of these cells to go to fire with a continuous short at least.


How many welds or weld spots is good? I use .2x8mm strip. I’ve never seen conductance tests of welds

Oh sorry I thought you meant the conductive connection to the cells was tape-only, no welding.

Then stopping the cells from moving relative to each other, in the face of high shock/vibrations is "all" you need to worry about.

The cells are also glued to the pcb. They’re pretty solidly held with the tape as well. Actually the taped nickel had some glue on the tabs and pcb covering maybe 20% of the area. I’m surprised to see almost exactly the same resistance as with the welded pack. No one has told me how they think it will fail! I’ve never seen taped connections done

So the tabs are welded to the batteries, but attached with "conductive paste" and by tape compression between stages on the side of the pack where visible?

Looks pretty stable, really. Zero used to use a compression fit for their battery conductors about 10 years ago. It can work if you do it right.

But in general it's more reliable, higher performance, and the same effort of assembly to use a more permanent means like solder or spot welding so that's preferred.

It is as u say and welded to the cell and then taped to the pcb w paste. It’s a bit easier to assemble but the main attraction to me is it’s conductive (so far) and allows someone to assemble a battery themselves if they get tabbed cells which have much less restrictions for legal shipping.

Hummina Shadeeba said:

tabbed cells which have much less restrictions for legal shipping.

Click to expand...

wut?

There a lot of restrictions on selling assembled batteries but not single cells. Single cells with tabs from what I read is still legally just a single cell but as soon as u connect cells it needs certification for some kinds of shipping and it’s very expensive to do that.
Seeing ups has less restrictions than usps

I thought the restrictions were based on kWh total in the box, not voltage.

Shipping along with other components much less restrictive.

As you say each carrier can set different rules, more restrictive than the government / international regulations.

I shorted this battery repeatedly while repeatedly trying to run a shorted motor on a computer. I didn’t know this was happening of course. My experience was to hear slight crinkling while doing the foc test on the vesc bldc tool. The motor doesn’t spin so I do the test again and again while looking at the battery and the crinkling stops and start with the test. Doing it again and again I will see little plums of smoke! from hard to pinpoint locations. I didn’t realize I was shoring and only later I open the motor and the windings are burnt and stink. I don’t know what current it was doing. Never had something like that happen


But forgetting that. I want to pot a battery. Maybe 100. 26650 size.
I want to Both fill the small triangle of the old steel Kona mountain bike and also add a metal plate to the potting which will be a motor mount. For starters is potting these 26650 a123 cells a bad idea and maybe will seal a safety release valve? I see all kinds of ion cells potted by Luna for example and these a123 are iron chemistry and safer


So far seems easy really and it just needs to be securely mounted into the frame. After spending two days staring at the bike I want the battery to both sit resting all the way down to the bottom bracket shell and also bolted to plates on the down and seat tubes. The potting resin would be pretty hard but maybe so these plates in something A bit softer.

Why not?


And run a belt of some sort to the rear wheel’s disk brake rotor mount.
And a “freewheel” on the motor shaft.


Planning to add mounting bolts to the potting and two xt90 plugs. Charge n discharge. And a 12s balance plug. Ill use wax and melt it out later.


Other than lining the interface of the block and frame with something, and maybe also filling the bike tubes with some very light resin.. it sounds doable.