EASY/FAST/INEXPENSIVE way to connect pouch-cells together

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pullin-gs   100 W

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EASY/FAST/INEXPENSIVE way to connect pouch-cells together

Post by pullin-gs » Jan 25 2020 10:07pm

The old tried-and-true process for connecting large pouch-cell tabs together.
This is NOT the EASY/FAST/INEXPENSIVE way....that is my second (below this one) post to this thread.
I've built four SPIM08AH packs using this described old method of aluminum bars clamped together with screws.
It works great, but is a slow time consuming process:
*) Requires aluminum stock to be cut, drilled.
*) Custom Screws, nuts and lockwashers (preferably all stainless)
*) Cell Tap for BMS: Copper tabs, round-hole base that fit in one of the screws into each junction.
*) Large space between packs to make room for assembled thick aluminium clamps on each cell.
*) Very heavy insulators (tape will rub through if clamps bind with each other) that surround each clamp.
*) Lock-tight? If a screw comes lose pack would become an inferno.
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Last edited by pullin-gs on Jan 25 2020 10:36pm, edited 2 times in total.

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Re: EASY/FAST/INEXPENSIVE way to connect pouch-cells together

Post by pullin-gs » Jan 25 2020 10:22pm

Here is an alternative process for consideration which I have used to build 1P SPIM08HP Lithium pouch-cell packs.
CAUTION/Disclaimer:****Home-built Lithium packs are dangerous and can cause damage to property and self!*****
That said, the below "clam-clip" method is better is so many ways than the aluminum clamp method I described above.
I've built two of these experimental packs using this process. The first one has been in heavy service (30-amps maximum) for my daily-driver pack for past 6 months: https://www.youtube.com/watch?v=mD_mHqUxeXw&t=102s
It works great for 1P packs, it is a very fast, inexpensive and less tedious process than using aluminum screw clamps.
*) Requires heavy copper tape, cut in lengths that cover ALL of the cell tab when the tape is folded in half length-wise.
*) Office Stationery Clam Clip Dispenser Refill packet....I used 3 clamps for each cell junction on first pack I built...picture uses 5.
*) Cells are taped together some thin double-side tape to keep them from sliding around.
*) Cell taps are easy...simply solder wire directly to outside tape surface AFTER each cell junction has clam-clips.

Cut tape to length of tap....must be large enough to cover tabs when folded over.
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Tape is wrapped around the two tabs STICKY-SIDE facing out and away from tabs. Shiny side touches tabs, NOT sticky side!!
Sticky side SUCKS as a conductor.
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Continuity is provided by tab-to-tab contact, and tab-to-copper contact. Clam-clips carry very little current (they are steel, connection to copper is very small area, and high resistance of adhesive)
Adhesive on tape is an additional safety measure which ensures tab will not slip off.
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Slide clam-clip onto tabs of cells using pressure from thumb. Not allot of force should be needed.
Do corner clam-clips first....are easier to put on.
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Done! Took me about 2 minutes to do. Be sure to cover entire junction. I use heavy 2-inch wide duck tape.
I add tap connectors (personal choice: I use voltage monitors....not a BMS) to wire, and shrink entire pack.
Finished pack is enclosed in aluminum box....I also tape all edges of each individual cell....edges can not touch other cells! Bad things will happen (fire).
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Last edited by pullin-gs on Jan 26 2020 9:33am, edited 14 times in total.

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Re: EASY/FAST/INEXPENSIVE way to connect pouch-cells together

Post by amberwolf » Jan 25 2020 10:27pm

if you look up some of the old a123 pouch cell threads, there are a number of methods tested and proposed, including variations on both of the ones posted in this thread so far.

should give you some data on what *not* to do, at least.

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Re: EASY/FAST/INEXPENSIVE way to connect pouch-cells together

Post by pullin-gs » Jan 25 2020 10:46pm

spinningmagnets wrote:
Jan 25 2020 10:17pm
I'm in the middle of doing this with some pouch cells. I'll post some pics when I'm done, and post results after I use it for a while. It's a 12V jump-starter for my car, plus a power back-up for phone and laptop during a short power outage (I live in tornado country). A direct hit from a tornado would be quite rare, but a region-wide power outrage for a couple days is a real concern.

They will be housed in a Apache case, a cheap copy of a Pelican case that is found at Harbor Freight. I am using clamps like the ones shown above...
I use these aluminum clamps when I built my 3P pack.....copper tape method described is probably no good for anything other than 1P.

PS: 3S3P SPIM08HP pack powers my e-kayak. It doubles as a power source for my spot-welder also. Will start my car (it has an 8-liter engine) if I ever have a need.

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Re: EASY/FAST/INEXPENSIVE way to connect pouch-cells together

Post by pullin-gs » Jan 26 2020 8:40am

Here are the clips I used.
https://www.ebay.com/itm/Office-Station ... 2749.l2649
Cost using clam-clips:
$1.36 of clam-clips will do a 10S1P pack.
$0.50 in copper tape is also needed to do a 10S1P pack.
Tools: scissors

Using the bar method took 10X more of my time.
Bar method Cost for 10S1P pack:
$5 in aluminum bars
$20 for stainless fittings: 20X screws/bolts/lock-washers
$2 for copper rings to solder BMS taps to.
Tools: Drill press, hack saw, drill bits, files.

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Re: EASY/FAST/INEXPENSIVE way to connect pouch-cells together

Post by 999zip999 » Jan 26 2020 6:17pm

How do you like those cells they sound interesting. Good price.

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Re: EASY/FAST/INEXPENSIVE way to connect pouch-cells together

Post by DogDipstick » Jan 26 2020 7:07pm

999zip999 wrote:
Jan 26 2020 6:17pm
How do you like those cells they sound interesting. Good price.

BAH no, Friend... . Lol. Ive tested a few and watched reviews. Mutiple low Ah reports ( even on Facebook as we speak) and polarized pouches ( some into the 3.3V+ region).. Not good!)

7Ah and more like 125 Peak, not 200A, Higher than advertised IR, lower than advertised capacity, less than advertised short circuit current. It takes three of thos in a 3s3p to short NEAR what it take to short one of my Chevy Volt cells in a 4s on the Kweld for SSC.. Then you get like maybe 1200A ( with a 3p) when a single Volt cell SSC for 2000A + Much less powerful than LGX NMC. I got datalogs. Zip.

Joe F tested em too.. Got a very mixxed batch.. i have talke w Charlie T and he got a 5Ah something.. and one with a hole in it... Here: https://www.facebook.com/groups/DIYBATTERY/

https://www.facebook.com/photo.php?fbid ... ater&ifg=1
Allota Watts @ 83.1v of raw QS power takes me everywhere on my Ironhorse DW link XC... :) Powered by Chevy. :D Broke 10 horses the other day. ( BTW; ...don't get hurt... :? )... (Currently building a battery datalogger.). :roll: Playin with (24) IRFB4115s now. :wink:

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Re: EASY/FAST/INEXPENSIVE way to connect pouch-cells together

Post by 999zip999 » Jan 26 2020 7:14pm

Plus I like 20ah cell or one more DDS it happens to be the right size. I don't want a 160 cell 20s8p pack because of connections. I really don't want a 3p pack of pouches Ping style.

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Re: EASY/FAST/INEXPENSIVE way to connect pouch-cells together

Post by pullin-gs » Jan 26 2020 10:58pm

999zip999 wrote:
Jan 26 2020 6:17pm
How do you like those cells they sound interesting. Good price.
The ones I have ordered are dated between 2013 and 2015.
These are USED cells from chinese hybrid fleet vehicles.
My first batch of 20 had two defective cells. Seller sent good replacements. All cells tested 3.7v+
My second batch of 16 were all fine. All cells tested 3.6v to 3.8V.
My third batch of 16 are all fine. All cells tested 3.7v to 3.9v.
All four packs I have made have delivered 7AH/cell @5A test loads.
Considering they are less than $2/cell these have delivered well and I consider them a good value.

Myth: These will do 200A. Maybe when they were new?? But 50-amps sustained is realistic.
IR is indeed higher than specs, but still very low compared to other my round-cell packs.
They are a bit on the heavy side: 10/oz per cell.

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Re: EASY/FAST/INEXPENSIVE way to connect pouch-cells together

Post by pullin-gs » Jan 26 2020 11:03pm

999zip999 wrote:
Jan 26 2020 7:14pm
Plus I like 20ah cell or one more DDS it happens to be the right size. I don't want a 160 cell 20s8p pack because of connections. I really don't want a 3p pack of pouches Ping style.
For 250w-750w builds, 1P packs using these cells are great.
For more range, suggest going with 18650...but you will have to pay much more.
For my 600w (1000W bursts) build, I use to run an 18AH 10S6P Sanyo 29E (18650 cell) pack....great 50 mile range, but is $$ just for the cells.
4 months ago, I gave the sanyo pack to my wife and started using my 11S1P build with these cells....I like it much better!
I have a second pack that I carry with me when we go for our longer (45 miles is my limit) rides.

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Re: EASY/FAST/INEXPENSIVE way to connect pouch-cells together

Post by pullin-gs » Jan 26 2020 11:05pm

duplicate post

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Re: EASY/FAST/INEXPENSIVE way to connect pouch-cells together

Post by 999zip999 » Jan 27 2020 12:41am

Yo bro love it Love you. I loved it with 7,000 watt but was very hard on my nerves with the a thin throttle delay now I'm at 4000 Watts and still of the same delay but I didn't handle it better.. I'm talking about my nerves same thing happened 2 the dogman. Slow down enjoy your bike ride smell the roses this is what I meant by what dogman as I understood it. 28 miles an hour spine 38 and 42 miles an hour you're missing The view
..

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Re: EASY/FAST/INEXPENSIVE way to connect pouch-cells together

Post by miro13car » Jan 27 2020 12:14pm

Are you sure those clamps would not move around once the pack is placed on ebike?
I always use screws with alu tabs
there are ways to prevent screws from going loose.
how do you connect balancing wires to those clamps? - you have to drill them or cell terminals to attach balancing wires. right?
with screws is much easier to connect balancing wires
Eplus, Bionx

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Re: EASY/FAST/INEXPENSIVE way to connect pouch-cells together

Post by pullin-gs » Jan 27 2020 12:28pm

miro13car wrote:
Jan 27 2020 12:14pm
Are you sure those clamps would not move around once the pack is placed on ebike?
I always use screws with alu tabs
there are ways to prevent screws from going loose.
how do you connect balancing wires to those clamps? - you have to drill them or cell terminals to attach balancing wires. right?
with screws is much easier to connect balancing wires

Summary: What prevents slippage:
1) Tabs/clip assenblies are enclosed/sealed using heavy layers of tape.
1a) In the event a tab breaks no lose pieces can happen.
2) No pack lateral cell movement. Cells are joined together using two-sided tape strips to prevent lateral movement and prevent cell-overheating. This is best-practices procedure for any pouch-cell pack build.
3) Clips are friction-fit to tab surfaces because of clip's squeezing action.
4) Clips adhere to copper tape's sticky film.
5) Copper tape bends inward due to clamp forces. The clips "dig-in"
7) No cell-to-cell cabling between clips that can pull on assemblies.
8 Pack is shrink-wrapped which creates forces that push clip assemblies INWARD towards cell, not put away.
6) There are ZERO external forces acting on clam-clips that would pull or bend clips away from tabs.
miro13car wrote:
Jan 27 2020 12:14pm
how do you connect balancing wires to those clamps? - you have to drill them or cell terminals to attach balancing wires. right?
with screws is much easier to connect balancing wires. This process is much easier to deal with cell taps.
I simply solder tap-wire directly to the copper tape....screws ARE NOT easier to attach tabs at all. This process does not need a ring-lug for BMS wire on each cell tap.

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Re: EASY/FAST/INEXPENSIVE way to connect pouch-cells together

Post by DogDipstick » Jan 27 2020 1:10pm

Well, I have my opiinions about building homemade lipos, and my tests. I do want to critique this build. Firstly, one thing sticks out to me.
6) There are ZERO external forces acting on clam-clips that would pull or bend clips away from tabs.
You have no consideration for heat ( thermal expansion and contraction of disimmilar metals.... ) to any degree of safety. Mechanical fasteners are based on the strength, as is the contact force. Shear load is very well laid out in engineering. Stainless also brittleness under great duress, therefore losing springiness. Also, the heat melts the adheshive, so if there is 80% of the clamping force clamping the tape on the tab ( that eventually melts) , the compression load is not transferred to the surfaces, it is used up in clamping the copper. The Spring rate of the spring would come into play here.

I think you need more contact force ( to sustain short circuit amperage without damage).

Also, the stickytape between pouches. i have not seen any OEm do it this way. I have seen the cells isolated ( every one) and also sitting loosly against each other in groups of ( small groups) two, but not any cells taped to each other ever. Do you know if the double sided tape is conductive? Some 3m tapes are.

More redundancy. I have primary, secondary, AND tertiary protection in every cell to cell contact I make that can potentially short to yeah other in a imperfect scenerio.

IDK, Ithink screws are to bulky and I dont like usiing ANy dissimilar metals (ONLY copper and Aluminum) along with a corrosioninhibiter.



I'm tellin you too, man, measure V potential to case (oof pouch) for ANY V... These cells dont play and melt a lil glue or grab alittle to much with tape and you got shorts down the road...


Yeah also, wanted to say TOm is a stand up guy and stands by what he sells. Never seen him not.
Allota Watts @ 83.1v of raw QS power takes me everywhere on my Ironhorse DW link XC... :) Powered by Chevy. :D Broke 10 horses the other day. ( BTW; ...don't get hurt... :? )... (Currently building a battery datalogger.). :roll: Playin with (24) IRFB4115s now. :wink:

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Re: EASY/FAST/INEXPENSIVE way to connect pouch-cells together

Post by DogDipstick » Jan 27 2020 1:18pm

I mean, yall know me by now, Imma OCD stickler... But.. I do make dam sure every place human hand touched on a cell is washed with soap, water, and the alcohol to remove ANy contaminant before final assy and wrap. Penetrox and seal with Kapton ( so you can see through it).

I even pickel every c-tap I stamp on the die press with Phospheric acid before final pressing and assy. Wash and dry, clean with alcohol. Use not corr. flux, but not like there is any of that left over even after the copper pickling.

Also wanted to make note of your balance line assy. YOu say you solder to the TAPE?

What happens when the tape heats up to the point of not adhering to the cell? What about repeated cycling with heat and resistance creep in the balance line? I never ever ever like soldering a cell directly and that is why I do this first with my C-taps. Pre-Pickle. Then the Pickling takes the lead corr. and copper corr. and flux away to a shiny seal able surface. Then wash, wipe, and assy.

Solder and Cu tape is not reliable. IMO. Sure you can solder on it, but it compromises the adhesive qualities.


IF I sees ANY fault a year or ten later, in the assy, I want to know DAM sure what caused it. I bet i could beat a bear in the face with one of my 6s packs, like a club swung by the discharge/balance leads, then put it back on the bike and ride away.
Allota Watts @ 83.1v of raw QS power takes me everywhere on my Ironhorse DW link XC... :) Powered by Chevy. :D Broke 10 horses the other day. ( BTW; ...don't get hurt... :? )... (Currently building a battery datalogger.). :roll: Playin with (24) IRFB4115s now. :wink:

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Re: EASY/FAST/INEXPENSIVE way to connect pouch-cells together

Post by miro13car » Jan 27 2020 2:18pm

clamps
as he wrote above they might loose it clamping force.
all battery manufacturers use welding for the reason.
I took apart Volt battery modules , took apart Leaf modules - they all use welding.
I built two 1P11S packs.
one from Leaf cells second from Volt cells.
7500 kilometers later I dont see any loose screws holding cell terminals.
cells used in my build works well below rated current - heating is minimal.

in your build? how do you connected +/- terminal wires??? also by soldering to copper ?
terminal wires must be at least AWG10 right?
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Re: EASY/FAST/INEXPENSIVE way to connect pouch-cells together

Post by pullin-gs » Jan 27 2020 3:46pm

miro13car wrote:
Jan 27 2020 2:18pm
clamps
as he wrote above they might loose it clamping force.
all battery manufacturers use welding for the reason.
I took apart Volt battery modules , took apart Leaf modules - they all use welding.
I built two 1P11S packs.
one from Leaf cells second from Volt cells.
7500 kilometers later I dont see any loose screws holding cell terminals.
cells used in my build works well below rated current - heating is minimal.

in your build? how do you connected +/- terminal wires??? also by soldering to copper ?
Terminal wires I use aluminum bar clamps (12x24 screws/nuts). Tin-plated copper eye-rings rated for 40-amps. They are crimp-style. I crimp cables in tight, then I solder also. I am running 12AWG silicon-ins copper wire (22 inches). Anderson PP connectors. Fused at 25amps.

LIPO pouch cells that use standard nickel/aluminum tabs do not weld well. Soldering is tricky as well.

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Re: EASY/FAST/INEXPENSIVE way to connect pouch-cells together

Post by Thach2264 » Jan 28 2020 9:12pm

I used these to clamp my pouch cell with 6mm screw. work very well and peace of mind that it wont fall apart.

https://www.amazon.com/gp/product/B06XR ... UTF8&psc=1

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Re: EASY/FAST/INEXPENSIVE way to connect pouch-cells together

Post by miro13car » Jan 29 2020 9:06am

that is interesting clamp from Amazon, never saw those before.
but it should be made from brass.
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Re: EASY/FAST/INEXPENSIVE way to connect pouch-cells together

Post by DogDipstick » Jan 29 2020 11:36am

pullin-gs wrote:
Jan 27 2020 3:46pm



Terminal wires I use aluminum bar clamps (12x24 screws/nuts). Tin-plated copper eye-rings rated for 40-amps. They are crimp-style. I crimp cables in tight, then I solder also. I am running 12AWG silicon-ins copper wire (22 inches). Anderson PP connectors. Fused at 25amps.

LIPO pouch cells that use standard nickel/aluminum tabs do not weld well. Soldering is tricky as well.
I got an Iron just for that. You dont see them often, but they are out there. Very powerful paddle iron. About 900 degrees.

(The HarborFreight 30w pencil is on the left. 1/5 of the power. )
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Allota Watts @ 83.1v of raw QS power takes me everywhere on my Ironhorse DW link XC... :) Powered by Chevy. :D Broke 10 horses the other day. ( BTW; ...don't get hurt... :? )... (Currently building a battery datalogger.). :roll: Playin with (24) IRFB4115s now. :wink:

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Re: EASY/FAST/INEXPENSIVE way to connect pouch-cells together

Post by pullin-gs » Feb 03 2020 4:27pm

"I got an Iron just for that."
You could fry a T-Bone with that!

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Re: EASY/FAST/INEXPENSIVE way to connect pouch-cells together

Post by miro13car » Feb 04 2020 12:23pm

the question is
what effect on pouch cell has solder temperature from such a monster soldering tool
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Re: EASY/FAST/INEXPENSIVE way to connect pouch-cells together

Post by DogDipstick » Feb 04 2020 5:21pm

miro13car wrote:
Feb 04 2020 12:23pm
the question is
what effect on pouch cell has solder temperature from such a monster soldering tool
Yeah I know. Fortunately the EV lipos have big, wide tabs, like 1 1/2 x 2 inches on the large format 60 Ah Lifepo cells I've been playing with.... But... Rivets are easier and safer IMO and I can't mess them up as easy... I agree. Honestly think it might be for soldering copper roofing and gutter or something... Never seen one like it.... it gets mega uniform hot. Almost beats my resistance soldering station from a MOT. Almost ( nowhere near actually lol)...


One good thing about those s p i m cells... They have very very thick tabs... the anode and cathode are some of the thickest metal I have seen in any electrical vehicle cell from my salvage works.

I like rivets. Clamping copper sammwiches. Then tap insulated, rubber, tape and finally mo rubber.
Allota Watts @ 83.1v of raw QS power takes me everywhere on my Ironhorse DW link XC... :) Powered by Chevy. :D Broke 10 horses the other day. ( BTW; ...don't get hurt... :? )... (Currently building a battery datalogger.). :roll: Playin with (24) IRFB4115s now. :wink:

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Re: EASY/FAST/INEXPENSIVE way to connect pouch-cells together

Post by SlowCo » Feb 05 2020 8:27am

For pouches with thin metal tabs that are long enough and not too wide maybe a tube squeezer key made of bare copper wire could be used to roll them up together. Then put small metal paper clamps over the rolled up tabs and remove the hinged wire "handles".
tube squeezer key.jpg
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