18650 battery Kit development and discussion[testing done]

Having my A123 cells dying one by one (22 out of 26 left) i had it. Needed a battery. Snath came up with idea which i had on my mind but discounted, thinking its not viable without even gettin into deeper. i was waiting for someone to come up with the kit so i dont have to but Snath threads got berried, long story short, i have decided to take a shot at it. Some members know me from my A123 kit time. I tried to gather info on most popular battery setups but there was not enough response so i thout that this one would draw a bit more attention. I think i am settled on the number of configurations i am prepared to work with. First, voltage and series setups. 2 positions, 14S and 22S. 14S because it is closest to 16S LiFePO4 so chargers are available with little adjustments; cell-man does it. Next one is 22S. 22S and not 20S because people who go for such setup are infor speed and power and 22S is i think the cap on most recent sine controllers without going mad.
At the moment i am thinking on 10P and 14P configurations. This would give adequate battery pack of 20-50AH depending on cell chosen.
My proposed kit will not have end termination and it will be necessary to think of one for your setup having in mind current handling. I hope i will be offering some extras, for example i have in mind a connector and flat cable for balancing. This connector has 22 pins for balancing and 3 20A pins that will be available for charging. 3 Pins because i think it will be posible to split pack in half and charge with hobby chargers.
Where i am at?
The design is done, cad is done. I have someone who will cut Polyurethane for the copper connector plates, i have someone who will make cover plates.
At the moment i don't have reliable supplier of 35Sh polyurethane with adhesive side. I have no source for 0.30mm copper sheet. (at least one did not came back to me with quote)
There will be 4 basic 18650 kits and people will be able to order extra copper/polyurethane plates, purchase balance/charge connector harness, side cover etc.
Here are some teaser renderings: (Renderings does not show polyurethane attached, colors for illustration at this time, thou sides will be lite grey or black)





















Exploded view:



I will use stainless bolts for compression. On the back side lid, rivet nuts and all setup will be flush.
I hope to get more input on this and help making it for us and not for me

Close up:



Peace,out

I like the idea of a compression kit a lot.
For me though a more modular characteristic to it would work better. 14P is good for my application but I would prefer to have multiple blocks of 4S to fit better in the funky "T" shaped battery box I have. I know neither of the 14S nor 22S configuration you are looking at can be divided by 4 but I'm just saying that modular smaller blocks of cells might be better for many instead of a huge 14 or 22S block.

Or maybe just do 1S blocks that clip or bolt to each other so that any number of cells can be put together in series, in many different shapes and easily hooked up to a BMS.

Fine argument but.. To satisfy everyone is a lot of expense and in the end the kit would be not atractive price wise. Instead I was looking to produce 4 battery kits that are 90% connection ready and have a shop to allow purchase of individual parts. For example I will have 4 standard top/bottom covers but you could be able to order bus bars etc individualy and make your top covers yourself. This also allows folks with less money to obtain necessary parts and DIY the rest them selves to save some cash.

Looks nice for a car or stationary home energy storage.
I would suggest to make more than only 2 serial connections on the end of the parallel strings.
What material will the compressing cover plates made of ?

I still think that 1S blocks that are easily held together and connected in series would allow everyone to configure the battery the way they need. You could have a couple parallel sizes to offer without bothering yourself with numerous series kits.

\/ampa said:

Looks nice for a car or stationary home energy storage.
I would suggest to make more than only 2 serial connections on the end of the parallel strings.
What material will the compressing cover plates made of ?

Click to expand...

+1. Look up dmun's suggestion on connecting every pair of cells in series with short bus bars and paralleling with a small gauge bus bar.

Good luck with this, I hope you make it work.

\/ampa said:

Looks nice for a car or stationary home energy storage.
I would suggest to make more than only 2 serial connections on the end of the parallel strings.
What material will the compressing cover plates made of ?

Click to expand...

There will be 5 cross conections on parallel bar.
The material most likely will be POM(Polyoxymethylene) or PC(Polycarbonate). Sides from PP(polypropylene)

The size of 14P22S would come out at 456x295mm. Not small but not too big for potential 3.8kWh pack. I did not mention but it will be no solder, no spot weld kit so the shape must be something manageable.
This is the tab layout and size:

This is what i have in mind for charging/balancing harness:

Looks like they are capable of up to 40A at 25C ambient. Might be good for mid power discharge and a tidy termination.

Pretty cool setup. Makes battery building easier.

I'm really interested, Agniusm. Can the pack be cut to split it for those of us who use split packs?
otherDoc

I am rethinking on size with the the input from ES facebook.
Perhaps 10s and 14s and somewhere between 6-8p and 10p
Four battery options total, no more.
It will allow for these options: 10s, 14s, 20s, 24s, 28s (advice from LMX bikes.. but as one contraption said: NEED MORE INPUT

agniusm said:

I am rethinking on size with the the input from ES facebook.
Perhaps 10s and 14s and somewhere between 6-8p and 10p
Four battery options total, no more.
It will allow for these options: 10s, 14s, 20s, 24s, 28s (advice from LMX bikes.. but as one contraption said: NEED MORE INPUT

Click to expand...

Have you thought of making small blocks that can be connected together? May not be as clean, but it would make it modular and simple... Like a 4x4 box, and then people just stack the cells whatever way is good for them (so if they want xs 8p, they just make x/2 boxes and so on). Or does this defeat the purpose? I guess it depends if the goal is to have a clean single box, or to turn regular cells into something easy to use without any welding (hence the compression).... Actually, the more I think about it, them more I think if you goal was modularity, we would need single cell compression devices, so I assume your goal is a clean box (which is still sweet).

Even in keeping with the single very clean box look; having the metal strips be adjustable would allow people to cram whatever configuration of s*p that equals the number of slots.

No modularity on my mind. Enough mess with rc lipo. I am not aiming to suit each individual, rather mases. Boy Jo can make contraption in hes garage. I am thinking of a battery pack that most use, battery pack that each and everyone can assemble without special tools, without damaging cells and yet have a clean battery with not so many wires hanging. Modular 5s5p, 4s4p, 1s5p is out of the question, dont even want to start discussion that way. I mean if someone uses 13s instead of 14s he could just leave one row empty etc.
10s and 14s is good combination, now for for the P I am not sure but 6p and 10p sounds good. If its too much, one could always use a123 18650 with 1.1ah to get their 10ah.

agniusm said:

No modularity on my mind. Enough mess with rc lipo. I am not aiming to suit each individual, rather mases. Boy Jo can make contraption in hes garage. I am thinking of a battery pack that most use, battery pack that each and everyone can assemble without special tools, without damaging cells and yet have a clean battery with not so many wires hanging. Modular 5s5p, 4s4p, 1s5p is out of the question, dont even want to start discussion that way. I mean if someone uses 13s instead of 14s he could just leave one row empty etc.
10s and 14s is good combination, now for for the P I am not sure but 6p and 10p sounds good. If its too much, one could always use a123 18650 with 1.1ah to get their 10ah.

Click to expand...

That is what I though. Wholely agree on just leaving a row empty.

Will the metal strips be adjustable though so that the same given space of 14x10 can be used to do anything (eg. someone could fit a 16s8p or 8p16s in a 14x10 case, it would just be a matter of how they are arranged)

Most of us could snip copper and resolder if we needed a different size.
otherDoc

BYqSXt8Z said:

That is what I though. Wholely agree on just leaving a row empty.

Will the metal strips be adjustable though so that the same given space of 14x10 can be used to do anything (eg. someone could fit a 16s8p or 8p16s in a 14x10 case, it would just be a matter of how they are arranged)

Click to expand...

Most likely not if you don't want to mangle the kit. You would be able to do something like that on your own with parts from the kit which will be available separately but compression plates (top and bottom) with side cover grooves will not fit and you will have to make them yourself. It will use standard 18650 cell holders so one could arrange the way he likes but copper/poron composite brackets will come in two sizes unless you order 100pcs which will be made custom at an extra cost. Covers will likely be also available but you wont want to pay for them unles you have in mind something large
I tried to fit most needs with A123 kits but in the end most that were bought was 16S and 24S with piled stuff that no body needed but was talked about and argued that it will be popular.

all very cool stuff!

Hey AgniusM
I would buy more 6S kits if I could get good A123 AMP20 cells but $75 plus shipping is way out of my range for those cells. Your kits were exceptionally fine. I am looking forward to purchasing one or 2 for the 18650 cells cuz my dream is Konions.
otherDoc

I know what you mean. At 75usd it would still be to expensive if it was in a form of finished battery. It was good experience thou. Very educational and I hope for people who purchased, still functional. I will take my time on this setup as it has a lot of potential and 18650 is going nowhere soon so good developed kit that could be made in to the battery by 10 year old is perfect.
I have started putting together sketches of new arrangements. Will include more components so visually it is more understandable.

Have done full exploded rendering of my idea of the kit. This is a 10S6P, the smallest one. It includes balancing harness and it could be discharged at 40A max. For more aditional connectors would need to be made:

Nice one.
This looks more like for LEV.
But i miss some venting holes or better a mounting hole for a little fan blowing fresh cold air in.
I did a relative fast charge with my 180pcs 25R BatBox battery with open ends and a temperature sensor in the middle of the pack.
The 25R have a very good IR compared to higher capacity or old laptop cells. They are rated 5A max. fast charge. I do fast charge with 3.4A.
The temperature was gone from about 30°C to nearly 50°C and i stopped than @4.05V (on a hot summer day but in a shade). So i will integrate a fan to it before i do it again.

I dont know whats with LEV? 135x223x85 seems still large for 10s6p? You better pedal then! If your cells overheat it means that you ether doing something wrong or your cells are garbage.
Have you seen a production battery with a fan? Everyone is trying to make them at least splashproof to avoid oxidation and the ones that are cooled are watter cooled to make them water proof in the end.

This is side by side 10S6P and 14S6P:

I have a question. Didn't thought about it thoroughly yet. We have this battery 10S6P. The negative wire runs from the back of the battery. Will it short if it rubs trough the cell pvc (whole can negative) and will touch the cell that is at front? Say 10th S cell with 1st S cell? I am designing it so the negative wire should be connected back to front and positive located as close to connector as possible.

agniusm said:

I dont know whats with LEV? 135x223x85 seems still large for 10s6p? You better pedal then! If your cells overheat it means that you ether doing something wrong or your cells are garbage.
Have you seen a production battery with a fan? Everyone is trying to make them at least splashproof to avoid oxidation and the ones that are cooled are watter cooled to make them water proof in the end.

Click to expand...

Just mean that the first model on top of this page is to huge for 2 wheeled Light Electric Vehicle.
I did not wrong! Overheat starts @60°C but all over 30°C makes cycle life shorter.
All original 25R cells yeah garbage but nothing better (w/kg + wh/kg + safety +price)available.
I only need fan ventilation when fast charging that's the only situation where they get too hot for my sense. So i close the venting hole to make splash proof when not charging fast.

Its just a suggestion from my experiences with boxed 18650 cells.

Water cooling is effective but heavy. nothing u want on a ebike.

\/ampa said:

Looks nice for a car or stationary home energy storage.
I would suggest to make more than only 2 serial connections on the end of the parallel strings.
What material will the compressing cover plates made of ?

Click to expand...

You have mentioned that before and since then it was changed if you dont follow.
It is not a full battery, only tha kit, so when you buy one from me, you could cut a hole in a side cover to put 40 or 60mm fan or do other improvements to your personal liking.