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

agniusm said:
Hey mate. Could you give some info on the foam you have used, linky would be nice. Also, what size dimples you have made, depth and diameter? Went through the thread and missed this info
Click to expand...

Re-read both his threads. There is too much foam related info to repeat easily, and it's the singular most important factor in this method of pack construction. If you use the wrong foam, your battery will fail. Use the right foam.
 
liveforphysics said:
agniusm said:
Hey mate. Could you give some info on the foam you have used, linky would be nice. Also, what size dimples you have made, depth and diameter? Went through the thread and missed this info
Click to expand...

Re-read both his threads. There is too much foam related info to repeat easily, and it's the singular most important factor in this method of pack construction. If you use the wrong foam, your battery will fail. Use the right foam.
Click to expand...

I have done that before posting my question and I am enough educated to understand that foam is most important in this build but there none technical properties discussion. Low set foam, OK but then there are tons of that stuff with different properies, at least 3 types of hardness. What I am trying to figure out and learn is what effect it will have using harder stuff than snath did? Is ist better with glue or without to allow some flex? What about tinning dimples for ox free result
 
agniusm said:
liveforphysics said:
agniusm said:
Hey mate. Could you give some info on the foam you have used, linky would be nice. Also, what size dimples you have made, depth and diameter? Went through the thread and missed this info
Click to expand...

Re-read both his threads. There is too much foam related info to repeat easily, and it's the singular most important factor in this method of pack construction. If you use the wrong foam, your battery will fail. Use the right foam.
Click to expand...

I have done that before posting my question and I am enough educated to understand that foam is most important in this build but there none technical properties discussion. Low set foam, OK but then there are tons of that stuff with different properies, at least 3 types of hardness. What I am trying to figure out and learn is what effect it will have using harder stuff than snath did? Is ist better with glue or without to allow some flex? What about tinning dimples for ox free result
Click to expand...

My choice of foam was based on trials of different thicknesses of four different types of foams/rubber-like materials (including office-type rubber bands, which worked great but degrade over time). Feel free to research and post results. I'm simply offering what works for me.
I only adhered one side of the foam (to the back of the bus bar) to keep the foam from moving around and out of place; the busbars are locked into position by the slots in the spacers. Don't know about tinning dimples...... might work. As noted above, I'm using some contact "grease" that I got from Big Moose; near as I can tell, it's some stuff you can get at autoparts stores.
Among the many things that I like about this battery:
- Hard case,
-Small size (in fact, you can reduce the height a bit by folding the bus bars down at both ends. I'm about to do that with a couple of batteries that I'm building now),
-No heat to ends of cells from soldering/spot welding,
-Shock absorption without bulk,
-Finished look..... no bubble wrap, duct tape, etc.,
-Inexpensive to build,
-With a little creativity, can be built with mostly hand tools, and
-Flexibility to quickly and easily do things like change out cells, reconfigure the pack, change mounting options, and finally, change/replace compression materials.
-Dimpled bus bar concept not limited to rectangular batteries.... I'm building a 10s5p stick battery that will fit into a 2 1/8 x 28 inch tube that will be the "backbone" of an F frame Moulton look-alike. The busbars will be rounded end star-shapes with reverse dimples (i.e. top-hat dimple for the positive end AND a reverse ring dimple for the negative end of the cell). Here's a picture:
 
snath,
what is the cost per cell for the parts to build this case?
thanks! nice job!
 
That is a pro work on that battery and terminals mate. I like the design very well and thought about it before you posted it at the time i was doing A123 kit as those 18650 are most common and price is best but discarded as unreliable contact method. Now that it is done properly I blame myself not trying:)
The thing about testing those materials is that they need lots of time and long real life testing enviroment, hence these questions regarding foam.
Are you using your old press for star reverse dimple terminal?
That is fine fine job, DIY as it should be.
I wander if there is some chemical approach of glueing polycarbonate? Need to do some research.
 
Matt Gruber said:
snath,
what is the cost per cell for the parts to build this case?
thanks! nice job!
Click to expand...

Hard to say really. It depends on what you have on hand, and you ability to creatively source (scrounge :) ) materials.
But, lets give it a try:
-Dimpling dies.... build or hire out???? I would encourage building. With the exception of the width of the copper strip and the height of the dimples, I've found that tolerances aren't all that critical so there's a lot of latitude in how a die is built.
-Poron foam (Part No. 86375K132) from Mc Master Carr $6.60 +shipping
-Polycarbonate sheet ~$15.00 from a home store
-Plastic welding solvent ~$16.00 +shipping
-Spacers not much money
-Copper ~$25.00 +shipping for a 1"x10' strip
-Miscellaneous wire, solder, connectors,thin film double sided tape (you can even get the foam with adhesive on one side), etc.
And that's about it. Problem is you have a lot of "leftovers" (foam, copper, and plastic welding solvent for example) so, for me, it's hard to arrive at a per cell cost.... could be from $2.00/cell for the first one to as little as $0.20/cell for subsequent builds.
 
agniusm said:
That is a pro work on that battery and terminals mate. I like the design very well and thought about it before you posted it at the time i was doing A123 kit as those 18650 are most common and price is best but discarded as unreliable contact method. Now that it is done properly I blame myself not trying:)
The thing about testing those materials is that they need lots of time and long real life testing enviroment, hence these questions regarding foam.
Are you using your old press for star reverse dimple terminal?
That is fine fine job, DIY as it should be.
I wander if there is some chemical approach of glueing polycarbonate? Need to do some research.
Click to expand...

The Poron-type foam is the stuff you find in car door/trunk gaskets. If these type materials last the life of a car, they are ok with me and my application. Just my opinion, but :p I wouldn't overthink this stuff and go with what is out there and works :) .
The die for the stars is new. It uses a series of five holes on a circle and a duplex (punch within a punch) type punch to center the dimples....... and a fair amount of handwork to get the star shape; the part starts out as a 2" disk.
If you would (I know it's a pain to go back over the posts) read back, you will find that I'm using Weld-on Type 3 solvent for gluing the case together.
 
Yeah, I bet there is a ton of fine fork with thw shape. I have reas both of you threads. There is a lot of irrelevant stuff posted by members abour air compresion and all that nonsense.
As far as I remember you were working with acrilic or pvc not polycarbonate!? Could be wrong thou.
 
agniusm said:
Yeah, I bet there is a ton of fine fork with thw shape. I have reas both of you threads. There is a lot of irrelevant stuff posted by members abour air compresion and all that nonsense.
As far as I remember you were working with acrilic or pvc not polycarbonate!? Could be wrong thou.
Click to expand...

Worked with both acrylic and PVC. I like PVC best because of its properties but it's a little difficult to get it in clear. Now I'm using polycarbonate because it's a bit stronger than acrylic (I knew that but I wanted to show that you can build a case with handtools by scoring and snapping acrylic). I'll cut the PC on the table saw and finish the edges with a router.
You can glue any of these with Weld-on 3.
 
Omg Snath!! Sweet!!!

file.php



I want! I want! Will you make me 11 of those? I can pay or trade stuff. :)
 
snath said:
The copper is .010" thick. The dimple punch is .187" and the die plate is .040" thick with .0218" holes.
Click to expand...

Snath, I'm in the process of building my own "dimpler", but got confused with the die plate thickness - is it .040" or .010" as per your first post third picture description?
snath said:
"Here are the two block halves, the 3/16 inch punch and the die plate of .010 inch sheet with .220 inch holes"
Click to expand...
 
jayx said:
snath said:
The copper is .010" thick. The dimple punch is .187" and the die plate is .040" thick with .0218" holes.
Click to expand...

Snath, I'm in the process of building my own "dimpler", but got confused with the die plate thickness - is it .040" or .010" as per your first post third picture description?
snath said:
"Here are the two block halves, the 3/16 inch punch and the die plate of .010 inch sheet with .220 inch holes"
Click to expand...
Click to expand...

Die plate is .040 for .010 thick copper. It can be a little less but the important thing is that the dimple height + the thickness of the copper isn't higher than the depth of the grooves in the spacer blocks... cause that's what keeps the bus bar captured and prevents it from moving around.
 
liveforphysics said:
Omg Snath!! Sweet!!!

file.php



I want! I want! Will you make me 11 of those? I can pay or trade stuff. :)
Click to expand...

This bus bar is designed to use PVC tube (McMaster Carr Part No. 8749K61) as the spacer bar. It just fits a hole punched with a Roper Whitney 17/32 punch. I'll glue a plug into each end to secure/draw up the end plates and compression foam. Power and balance leads follow the grooves along the outside of the cells. At least one of the grooves will be filled with 1/4" PVC "anti-rotation bars". Shrink Wrap is mandatory to keep the cells in place.... especially when outside the housing.

I will anneal the bus bars because of the amount of cold working required.
 
I'm stuck here. I removed the tabs from most of my cells already and soldered 40-50 poorly. I want to do the pack, but my end battery size is around 210 cells if I go the solderless route (reasons). I could pay for the materials to go solder-less or I could pay batteries plus to spot weld new tabs on the cells so I can solder to tabs instead of to cells.

I have copper wire already, would that work instead of a copper strip

Which route would be cheaper?
 
lxgoldsmith said:
I'm stuck here. I removed the tabs from most of my cells already and soldered 40-50 poorly. I want to do the pack, but my end battery size is around 210 cells if I go the solderless route (reasons). I could pay for the materials to go solder-less or I could pay batteries plus to spot weld new tabs on the cells so I can solder to tabs instead of to cells.

I have copper wire already, would that work instead of a copper strip

Which route would be cheaper?
Click to expand...

I don't think wire will work with this pack build. The whole concept is copper strip with dimples.

I don't have any idea which route would be cheaper. You can look up thread and get some idea of what materials cost and compare that to what Batteries Plus would charge.
 
i think this method wont work on used cells. If you pull spot welded tabs off it somewhat deforms cell terminals and they are no more as flat as new making less contact area with the dimple. Same goes for solder, a lot of work to clean them properly.
 
I removed the tabs from most of my cells, so I'm looking for ways to connect them, including battery holders and no solder methods
 
if i had those 50 single cell holders, i'd upgrade to 14awg tinned copper directly touching the cell, 10s5p would be my pack. cheap and easy to swap a cell anytime.
 
The NTS pack looks good but the price is a bit high and the BMS current is very low also ?
 
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