Another No Solder/Weld 18650 Build (Updated 03/09/2014)

I looking to make one of these no solder/weld battery packs using some Sony US18650VTC4's which I have ordered and are on the way and have been looking around for the bits to make it.

I have problems sourcing the Poron urethane blanket. (I'm in New Zealand). Would neoprene rubber strip work as a substitute?
 
kiwipete said:
I looking to make one of these no solder/weld battery packs using some Sony US18650VTC4's which I have ordered and are on the way and have been looking around for the bits to make it.

I have problems sourcing the Poron urethane blanket. (I'm in New Zealand). Would neoprene rubber strip work as a substitute?
Click to expand...
I haven't tried it but I think the closed cell foem used in building footings would work. It comes in rolls. try you nearest builder supplier to have a look at it. You have Bunnings over there? they sell it.
 
One would be best off not guessing with a foam they think will or will not have safe levels of compression-set.


Get the relevant compression-set % data. Ensure you crush it by more than that amount if you want it to keep your cells connected long-term.

It is not hard to do this, but you can't ensure your success by going of hunches or assumptions on materials choice, or it could result in fire.

It is 100% impossible to squeeze a chunk of foam between your fingers and know ANYTHING related to it's compression-set behavior will be after it's been in squeezed in your battery for a few months.

Simply checking material property datasheets are really the difference between a long-lasting great pack and a potential home fire, spend the effort to use proper materials.
 
liveforphysics said:
One would be best off not guessing with a foam they think will or will not have safe levels of compression-set.
Get the relevant compression-set % data. Ensure you crush it by more than that amount if you want it to keep your cells connected long-term.
Simply checking material property datasheets are really the difference between a long-lasting great pack and a potential home fire, spend the effort to use proper materials.
Click to expand...

I totally agree with you lfp, but none of the NZ based suppliers have any data sheets listing compression set on their websites, and the ones I contacted via phone were unable to provide solid info re compression set either.

I have considered buying the same stuff that 'snath' used and contacted McMaster-Carr via email about purchasing some and shipping to New Zealand. Their reply was quick but extremely unhelpful:

"Due to the complexity of U.S. export regulations, McMaster-Carr accepts international orders only from our established customers. This decision also applies to orders shipping within the United States, because it is based on the final destination of the items. We will not provide a quotation or accept your orders."

So much for that...

The foam itself is not that expensive ($6.60 for a 12" x 12" sheet) and I imagine that if it was folded or cut to fit a big size envelope, mailing it would not be too horrendous either.So if there is a kind ES (US based) member who is willing to help out here, please PM me. I'll pay all costs upfront (Paypal would be easiest).
 
Masterful job sir. Is there any advantage for using the multi pin connector instead of say an XLR for the charge connector?
 
Bronko said:
Is there any advantage for using the multi pin connector instead of say an XLR for the charge connector?
Click to expand...

I use 11 of the pins on the DB 15 connector to hook up to a mating DB to JST XH connector that goes to the Balance port on my charger. I suppose you could use an XLR-type connector but I'm not sure if you can get one with enough pins. I'm about 100% sure it wouldn't fit in the space that a DB connector takes up. Finally, the DB 15 is what I had on hand :)
 
Bronko said:
I agree that a video time lapse on this build would be awesome.
Click to expand...
I'm pretty much a "technological Luddite" when it comes to that sort of thing. But if you look at the pictures, it's all there. Once you make the die block to make the dimples and fit them up to the spacer blocks, it becomes easier to visualize.
 
snath said:
Bronko said:
I agree that a video time lapse on this build would be awesome.
Click to expand...
I'm pretty much a "technological Luddite" when it comes to that sort of thing. But if you look at the pictures, it's all there. Once you make the die block to make the dimples and fit them up to the spacer blocks, it becomes easier to visualize.
Click to expand...

I'm about to make a couple of 10s4p packs so Ill try to throw up a few more pictures of the steps/process. Is there anything in particular(steps/process) that you are interested in?
 
kiwipete said:
liveforphysics said:
One would be best off not guessing with a foam they think will or will not have safe levels of compression-set.
Get the relevant compression-set % data. Ensure you crush it by more than that amount if you want it to keep your cells connected long-term.
Simply checking material property datasheets are really the difference between a long-lasting great pack and a potential home fire, spend the effort to use proper materials.
Click to expand...

I totally agree with you lfp, but none of the NZ based suppliers have any data sheets listing compression set on their websites, and the ones I contacted via phone were unable to provide solid info re compression set either.

I have considered buying the same stuff that 'snath' used and contacted McMaster-Carr via email about purchasing some and shipping to New Zealand. Their reply was quick but extremely unhelpful:

"Due to the complexity of U.S. export regulations, McMaster-Carr accepts international orders only from our established customers. This decision also applies to orders shipping within the United States, because it is based on the final destination of the items. We will not provide a quotation or accept your orders."

So much for that...

The foam itself is not that expensive ($6.60 for a 12" x 12" sheet) and I imagine that if it was folded or cut to fit a big size envelope, mailing it would not be too horrendous either.So if there is a kind ES (US based) member who is willing to help out here, please PM me. I'll pay all costs upfront (Paypal would be easiest).
Click to expand...



Ebay or whatever you have to get proper material for the foam. This battery is so tolerant of substitutions on all other materials, but the foam must be right for success.
 
liveforphysics said:
Ebay or whatever you have to get proper material for the foam. This battery is so tolerant of substitutions on all other materials, but the foam must be right for success.
Click to expand...

I found out since then that the NZ Post office has a service for cases like this. You get the company to send it to an NZ Post run office/warehouse in the US and they then onsend it to NZ.

Shipping cost are pretty painful ($5 (US) from McMaster Carr to Portland OR and then NZD$31.50 to go to NZ), but at least I can get the right stuff. Now just waiting for the batteries..
 
How much of a contact patch do you expect between the bus and battery?

I am experimenting with forming bus bars with the required dimples. I drilled a hole in some steel and have been using a steel rod with a rounded end (hammered) to create the dimples.

I have been able to make them all the same depth, but the shape is not always consistent.

Thanks for any reply.
 
Was looking for a way to make a small 4s4p battery out of 18650 cells (small I know) - this solution is perfect - thanks so much <pats Snath on the back>.
As always, continue to be amazed by the ingenuity and innovation of the ES members...it seems whenever I encounter a problem, there is already a multitude of solutions to hand!
Now, time to see if I can source most of the materials (or appropriate substitutes) locally...don't worry LFP, I'll ensure the right compression material is used!
 
Pat Eaton said:
How much of a contact patch do you expect between the bus and battery?

I am experimenting with forming bus bars with the required dimples. I drilled a hole in some steel and have been using a steel rod with a rounded end (hammered) to create the dimples.

I have been able to make them all the same depth, but the shape is not always consistent.

Thanks for any reply.
Click to expand...


I suppose to answer that one would need to know the expected current delivery capabilities of the cell you're running in short circuit.

If you just want a rule of thumb though, I would try to target at least a 4mm^2 flat contact area.

Does anyone want to make the compound #70 silicone gel polymer and graphene dielectric grease? I doubt too many people would want to spend the few hundred bucks to make the lowest quantity batch. I am personally interested in testing the stuff out because I've heard talk of some seemingly impossible contact resistance numbers. I would assume 1-2mg/cell would be enough if you design your cell contact dimple well and get it decently flat with a fine-stone or something. I have the equipment to blend up a batch if I bought the raw materials. and transfer it into perhaps 0.5cc-1cc syringes with blunt needle tips for applying if anyone would be interested. It would obviously be at least >100x the cost per unit of volume of any non-nano-conductor based dielectric grease, but since so little could do so many cells, it would be perhaps a few cents per cell to potentially get conductivity I've heard claimed as better than many welding processes.
 
Pat Eaton said:
How much of a contact patch do you expect between the bus and battery?

I am experimenting with forming bus bars with the required dimples. I drilled a hole in some steel and have been using a steel rod with a rounded end (hammered) to create the dimples.

I have been able to make them all the same depth, but the shape is not always consistent.

Thanks for any reply.
Click to expand...

If you will take a look at my dimpling punch, you'll notice that it is flat on the end; resulting in flat dimples. I made it out of a 3/16 high speed tool bit and barely knocked off the corner to keep it from cutting the copper. The resulting dimple is about 17 sq mm.
 
liveforphysics said:
Pat Eaton said:
How much of a contact patch do you expect between the bus and battery?

I am experimenting with forming bus bars with the required dimples. I drilled a hole in some steel and have been using a steel rod with a rounded end (hammered) to create the dimples.

I have been able to make them all the same depth, but the shape is not always consistent.

Thanks for any reply.
Click to expand...


I suppose to answer that one would need to know the expected current delivery capabilities of the cell you're running in short circuit.

If you just want a rule of thumb though, I would try to target at least a 4mm^2 flat contact area.

Does anyone want to make the compound #70 silicone gel polymer and graphene dielectric grease? I doubt too many people would want to spend the few hundred bucks to make the lowest quantity batch. I am personally interested in testing the stuff out because I've heard talk of some seemingly impossible contact resistance numbers. I would assume 1-2mg/cell would be enough if you design your cell contact dimple well and get it decently flat with a fine-stone or something. I have the equipment to blend up a batch if I bought the raw materials. and transfer it into perhaps 0.5cc-1cc syringes with blunt needle tips for applying if anyone would be interested. It would obviously be at least >100x the cost per unit of volume of any non-nano-conductor based dielectric grease, but since so little could do so many cells, it would be perhaps a few cents per cell to potentially get conductivity I've heard claimed as better than many welding processes.
Click to expand...

I just bought some grease used in automotive electrical service from Big Moose but I would be willing to participate in a batch of the super dielectric grease in the interest of refining this pack building method.

I don't think these dimples need much flattening after they are punched especially if one doesn't cold-work the copper too much with excessive flexing. The copper is flat when it leaves the dimpling block and, if still soft, the dimples are readily pushed flat against the cells by the compressed urethane.
 
Silicone grease isnt recommend if the contact pressure is low but maybe with graphene who knows

Cant wait for vapor desposited graphene on all our electrical contacts including cell terminals but for now



Gold plate the busbar and ur done for now. Anything is better than raw copper for contacts if u care about contact resistance rather than thermal

But how much would you guys pay per gold plated ncr18650pd cell?
 
flathill said:
Silicone grease isnt recommend if the contact pressure is low but maybe with graphene who knows

Cant wait for vapor desposited graphene on all our electrical contacts including cell terminals but for now



Gold plate the busbar and ur done for now. Anything is better than raw copper for contacts if u care about contact resistance rather than thermal

But how much would you guys pay per gold plated ncr18650pd cell?
Click to expand...


I've got a plasma metal sputtering machine in my garage and a gold foil target. :) I'm not sold on gold over clean copper or silver though, but I agree gold tends to stay clean longest. If cleaned before coated in compound #70, copper can stay pretty nice if you keep it dry.
 
flathill said:
Silicone grease isnt recommend if the contact pressure is low but maybe with graphene who knows

Cant wait for vapor desposited graphene on all our electrical contacts including cell terminals but for now



Gold plate the busbar and ur done for now. Anything is better than raw copper for contacts if u care about contact resistance rather than thermal

But how much would you guys pay per gold plated ncr18650pd cell?
Click to expand...

Maybe one of these? http://www.caswellplating.com/plug-n-plate-brush-plating-kits/plug-n-plate-gold-kit.html

I use one for plating silver on to copper findings for flame worked glass pieces my wife makes. It works pretty well but the plating thickness is pretty thin and would probably rub off over time in a pack. Some type of compound would probably work better.
 
standard copper nickel coating results an order of magnitude less
contact resistance than clean uncoated 99.99 pure oxgen free copper

if i remember correct

gold porosity is inversely proportional to the thickness for small range starting from zero

or is it the reverse

gold plating would need to be relatively thick to be optimal but even a thin layer would make a huge diff
 
kiwipete said:
liveforphysics said:
Ebay or whatever you have to get proper material for the foam. This battery is so tolerant of substitutions on all other materials, but the foam must be right for success.
Click to expand...

I found out since then that the NZ Post office has a service for cases like this. You get the company to send it to an NZ Post run office/warehouse in the US and they then onsend it to NZ.

Shipping cost are pretty painful ($5 (US) from McMaster Carr to Portland OR and then NZD$31.50 to go to NZ), but at least I can get the right stuff. Now just waiting for the batteries..
Click to expand...
Have you had a look at "shipito"?? thsy are a forwarding agency I have used for amazon things. You can choose what service / price they use to send it on. I can't see NZ being any different to Oz.
 
Awesome idea, great build!
Here is my 2 cents in the picture...
HAND DIMPLING.jpg

Waiting for spacers 12s8p but cannot buy closedcell compressing foam... Can someone send me stripes for my battery in envelope? I am in EU. PM

Thank you
opzopus
 
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