Question for pouch cell battery pack (im a full on idiot)

[TheoneKnocker]

This is what I mean by 2p being a minimum:

So I was thinking this entirely wrong, so if I want a 2p pack I will need 120 cells if I am doing 30s a pack. This makes a little sense, so I would need 120 cells and 4 bms's to balance these cells, are these 4 blocks of cells connected in series? In the third image are those 20s cells first in a series configuration then by the last bus bar connected in parallel? because I don't understand how they are connected in parallel apart from the bus bar since both packs are separate. And what if instead of the 4 packs in the 3rd image i use just 2 battery packs, connected like that with the bus bar with 2 bms's would that give me my 30s2p or would i need to do the 4 battery packs to get a 2p connection

 

[TheoneKnocker]

This is what I mean by 2p being a minimum:

My main question was how are they connected together to make a series parallel connection? Thats the part i dont understand.

 

[gromike]

Draw a diagram of what you want to build and you will see, it's basic electricity. If you don't understand that, your build of a large battery bank will end in some sort of disaster.

 

[TheoneKnocker]

Draw a diagram of what you want to build and you will see, it's basic electricity. If you don't understand that, your build of a large battery bank will end in some sort of disaster.

I just dont understand these types of batteries, the small cylindrical li ion i understand them and even found a perfect way to connect them according to a youtube video that used nickel strips + thin copper sheets to connect 2 rows together, but ive never found and still haven't found anything about these batteries (apart from his perfect designs and builds) what configuration is the pack in the 3rd image?

 

[jonescg]

My main question was how are they connected together to make a series parallel connection? Thats the part i dont understand.

Look carefully at the cells. On a single stack of cells, there's pairs of cells facing one way, and then the other way. Fwd, Fwd, Back, Back, Fwd, Fwd, back, back... The tabs of both paralleled cells are folded towards each other with the punched hole overlapping above the screw hole.

 

[jonescg]

So I was thinking this entirely wrong, so if I want a 2p pack I will need 120 cells if I am doing 30s a pack /

No, a 30s2p pack is 60 cells in total. If each cell was 5 Ah, you now have a 10 Ah battery of ~100 V nominal.

 

[TheoneKnocker]

Look carefully at the cells. On a single stack of cells, there's pairs of cells facing one way, and then the other way. Fwd, Fwd, Back, Back, Fwd, Fwd, back, back... The tabs of both paralleled cells are folded towards each other with the punched hole overlapping above the screw hole.

What configurations are the cells setup in, in the 3rd image?

 

[TheoneKnocker]

Look carefully at the cells. On a single stack of cells, there's pairs of cells facing one way, and then the other way. Fwd, Fwd, Back, Back, Fwd, Fwd, back, back... The tabs of both paralleled cells are folded towards each other with the punched hole overlapping above the screw hole.

How are the cells setup? 2 facing with their postive and negative and other 2 facing with their negative positive?

 

[jonescg]

This battery was a 168s2p pack. So each block of cells was 42s2p. You can see from the front of the block that I've temporarily terminated one of the final terminals with a small rectangle of 2 mm copper with a single hole in it. This was later removed and linked to the next block of 42s2p by means of a copper buslink. But, that one screw held down the positive (or negative, I forget) tabs of both cells in parallel. Same for all the other ones, except they were linked in series with the next pair, and so on.

 

[TheoneKnocker]

This battery was a 168s2p pack. So each block of cells was 42s2p. You can see from the front of the block that I've temporarily terminated one of the final terminals with a small rectangle of 2 mm copper with a single hole in it. This was later removed and linked to the next block of 42s2p by means of a copper buslink. But, that one screw held down the positive (or negative, I forget) tabs of both cells in parallel. Same for all the other ones, except they were linked in series with the next pair, and so on.

It looks extremely powerful (and it super duper is), would it be tough to make that type of battery? also did you only use cell balancers to avoid them getting out of balance instead of a whole bms? if so i would love to make something like this.

 

[jonescg]

No, definitely used a BMS for this pack. It was a dyno pack for a motor-generator combination. Unfortunately the guys running it pushed the limits and pushed it a bit hard, but it served it's purpose.

It wasn't tough, but it's the result of years of practice and iterative improvement.

 

[TheoneKnocker]

No, a 30s2p pack is 60 cells in total. If each cell was 5 Ah, you now have a 10 Ah battery of ~100 V nominal.

Okay, so to build my battery pack I would need 60 lipo cells, would I need to set them up in a series way first to get my voltage? then somehow connect them in parallel so I can get double the capacity, only issue is that I don't know how to do the parallel connection? Or do I have to do some other type of configuration so I would be able to connect them in parallel?

 

[jonescg]

This is a close up of how to stack the cells. Two facing one way, two facing the other way, two facing the first way, and so on.
The buslinks will join one pair of positive tabs to the the next pair of negative tabs. Just study this assembly real carefully and see what I'm getting at. If you're building it from 5 Ah cells, you'll just have two columns of cells, both arranged as a 15s2p. You'd then series link these two.

 

[TheoneKnocker]

This is a close up of how to stack the cells. Two facing one way, two facing the other way, two facing the first way, and so on.
The buslinks will join one pair of positive tabs to the the next pair of negative tabs. Just study this assembly real carefully and see what I'm getting at. If you're building it from 5 Ah cells, you'll just have two columns of cells, both arranged as a 15s2p. You'd then series link these two.

Ok now this is makes perfect sense, How would one go around connecting them in series with the copper bus bars? So what i understand is that I need to have 2 bricks of 15s2p with this same layout but the tricky part is the series which I do not know how to do. Also should the 15s2p be on one single pcb, and then another for the other pair?

 

[jonescg]

Ok now this is makes perfect sense, How would one go around connecting them in series with the copper bus bars? So what i understand is that I need to have 2 bricks of 15s2p with this same layout but the tricky part is the series which I do not know how to do. Also should the 15s2p be on one single pcb, and then another for the other pair?

 

[TheoneKnocker]

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Thank you extremely for all of this information, sorry that i have been disturbing you and acting like an idiot but this is truly my first time with these batteries, I was going to ask if i have to connect them like the batteries in the 3rd image were, i guess this is the end, thank you extremely for everything.

 

[jonescg]

The third image is of a 6p battery under construction. Sketch's battery actually.

 

[TheoneKnocker]

The third image is of a 6p battery under construction. Sketch's battery actually.

Also how could i connect more than 2p batteries together, i want a little more capacity, would i need to connect the ends at the front together on the empty spaces?

 

[TheoneKnocker]

Also how could i connect more than 2p batteries together, i want a little more capacity, would i need to connect the ends at the front together on the empty spaces?

Thinking of a 4p configuration since that would be more than enough i just need to know how to connect them after i make the battery packs at the end for the series connection (either way 2p is the best for my use case but if i could have more i would want to)

 

[TheoneKnocker]

The third image is of a 6p battery under construction. Sketch's battery actually.

One final question, could I use this design on the giant cells that hold 76Ah, could i drill a hole in the tabs, connect them one over the other like the small pouch cells and then connect them via copper bus bars to get the same power? Or would I have to improvise with a different design? (thinking more of a series pattern as in 2 positive cells and 2 negative cells tabs folded over each other and once I make it to the end I connect the end cell with the other battery pack configured in the opposite of the first one)

 

[DogDipstick]

Say what ? Says who?

uke Workman. On this forum.

"tens of thousands of cycles"

 

[DogDipstick]

One final question, could I use this design on the giant cells that hold 76Ah, could i drill a hole in the tabs, connect them one over the other like the small pouch cells and then connect them via copper bus bars to get the same power? Or would I have to improvise with a different design? (thinking more of a series pattern as in 2 positive cells and 2 negative cells tabs folded over each other and once I make it to the end I connect the end cell with the other battery pack configured in the opposite of the first one)

I have built many. I use a stamped copper plated ( Eriflex Flexibus) bar, cut on saw, folded in seven upset operations. I make a vampire punch for repeat accuracy and punch holes in all tabs regularly. I use ULINE or BANDIT banding to apply the restraint compression on the face of the cell. You can look at my old post: many example within.

The dimensions you can tolerate are up to you. You set the standard as to how close the cells are.. and do not stress. It is very tough to fit many P into a series without stuffing and stuffing and making special consideration. tabs become to short.. you fight fight and lose.... You try to stuff many cells into series and you create problem.

So I use my folded copper plate but you can also get collector plate PCB systems and use them for many P assembly. 1p with my copper folded plate is easy: 2p is easy: from 3p onward it gets cumbersome and troubling.

Example shown here. The collector plate system might be a better idea for many P pack. You do not want to stuff, or fight the cells, of lose cell to cell isolation, and must apply good constraint to the pack structure.

 

[TheoneKnocker]

I have built many. I use a stamped copper plated ( Eriflex Flexibus) bar, cut on saw, folded in seven upset operations. I make a vampire punch for repeat accuracy and punch holes in all tabs regularly. I use ULINE or BANDIT banding to apply the restraint compression on the face of the cell. You can look at my old post: many example within.

The dimensions you can tolerate are up to you. You set the standard as to how close the cells are.. and do not stress. It is very tough to fit many P into a series without stuffing and stuffing and making special consideration. tabs become to short.. you fight fight and lose.... You try to stuff many cells into series and you create problem.

So I use my folded copper plate but you can also get collector plate PCB systems and use them for many P assembly. 1p with my copper folded plate is easy: 2p is easy: from 3p onward it gets cumbersome and troubling.

Example shown here. The collector plate system might be a better idea for many P pack. You do not want to stuff, or fight the cells, of lose cell to cell isolation, and must apply good constraint to the pack structure.

Thank you extremely, i wanted a 2p pack since a seller on Alibaba claimed 60ah with 3-10c discharge, great for my use case since I'm trying to build a racing vehicle (not quite but something that's Fast) and has the capacity to drive for more than 10 minutes and since the batteries are so powerful I think ill achieve the power goal the motor demands, ill be using the cells with 1 tab up and 1 tab down, so ill have to connect them probably like a snake from up to down all the way to the end (ofcourse making them like the batteries above 2 forward and 2 back) then jump them to the other pack like in jonescg's pack from above.

 

[TheoneKnocker]

I have built many. I use a stamped copper plated ( Eriflex Flexibus) bar, cut on saw, folded in seven upset operations. I make a vampire punch for repeat accuracy and punch holes in all tabs regularly. I use ULINE or BANDIT banding to apply the restraint compression on the face of the cell. You can look at my old post: many example within.

The dimensions you can tolerate are up to you. You set the standard as to how close the cells are.. and do not stress. It is very tough to fit many P into a series without stuffing and stuffing and making special consideration. tabs become to short.. you fight fight and lose.... You try to stuff many cells into series and you create problem.

So I use my folded copper plate but you can also get collector plate PCB systems and use them for many P assembly. 1p with my copper folded plate is easy: 2p is easy: from 3p onward it gets cumbersome and troubling.

Example shown here. The collector plate system might be a better idea for many P pack. You do not want to stuff, or fight the cells, of lose cell to cell isolation, and must apply good constraint to the pack structure.

Also id like to ask you, do you have any design or explanations on how to connect 3 or 4p of these types of batteries? Either mine battery i had in the image or your battery would still be the best.

 

[TheoneKnocker]

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Would there be any negative effects storing pouch cell batteries in plexiglass, id like for my battery pack to be see through and look different from every other electric moped in my city.