Battery assembly kit for 18650 cells - first prototype

[spinningmagnets]

I have had good luck cutting strips apart with a dremel using a thin abrasive wheel, and that is the method that I would use for pulling a bad cell out of the middle of a pack that was assembled like this.

As far as how to replace a cell...the assembly method requires that the builder has a simple spot-welder, so I would recommend considering the option of carrying a "repair kit" that might look something like this:

 

[circuit]

Yes, good insight. I am thinking of similar repair kit as well. I have also had a good success using dremel tool for grinding-out spot welds of cell tabs, this is why I mentioned this method on post 1

 

[999zip999]

With a dremel and or diamond wheel there's a rat tail that can get lose and short. Must be careful of the loose metal.

 

[Arbol]

I subscribe to this thread. Thanks.

 

[Doctorbass]

I know that the tesla battery are using the ultrasonic wire weld to the cell tab and to the main bus plate.

The wire bond is also acting like a fuse.

http://www.teslamotorsclub.com/attachment.php?attachmentid=22948&d=1370081801

http://www.teslamotorsclub.com/attachment.php?attachmentid=22949&d=1370083532

That is also a great solution.

Circuit I subscribed to your great thread.

Doc

 

[circuit]

Sorry for keeping you guys waiting so long, my shipment from China is very slow... I tried to save a few bucks and ship it all combined with my other stuff via sea. There have been several holdups. I ask for your patience for couple more weeks.

 

[Gab]

cool design any news ?

 

[circuit]

Still waiting for package with tab material from China.. any week now...

 

[silviasol]

Is that copper sheet? What thickness?

 

[circuit]

No, this is steel. Just a test for laser accuracy. Actual thickness and material is still to be defined, until I receive some samples.

 

[circuit]

OK, finally I have some news. Some good, some not so much.

 

[madin88]

nice to see all fits well together
what about a redesign of the fuse and the spot weld tabs?
i think one fuse and a round plate (with place for 5-6 pot welds) will work well and the laser cut will take much less time..

 

[circuit]

Yes, you are right. Drastically redesigning even negative pole will cut the price in half. One tab with 6 positive ends and 6 negative ends adds up to 1200mm cutting length (wow, for such small part). Multiply that by 12 pieces and by cutting price per meter and it is still too expensive. Let's say $45 for 12s6p kit. I can take such beating for my personal hobby, maybe couple more geeks will too, but it's not for the masses. And we do need masses to properly debug this projects and turn it to real product...

 

[circuit]

OK, good news. I've found a different solution for tab cutting. A lot cheaper. I have also redesigned a plastic tray, which should cut down the price as well. And I also have a cheap solution for cutting of isolation paper.
So overall, my initial guess of $69 kit's prime cost looks realistic again. Selling price could be around $89.

No pictures yet, sitting in airport now..

 

[cal3thousand]

Just posting to let you know that I just found this thread and have interest.

 

[crossbreak]

me too

 

[madin88]

what are the overall dimensions of this 12s6p pack?

 

[arkmundi]

Thanks for the heroic effort to enable us ES'ers in our battery making. Unfortunately, I already made the commit to the A123 26650 cells - I have a full 100-count carton. So, QUESTION: any chance when you're finished with this kit that you'll replicate for the 26650?

 

[circuit]

26650 is very likely to come, however there is one problem: to get a reasonable price for tabs, I have to order a relatively large quantity (enough for 120s8p pack).

Currently I'm on mobile, so can't say exact dimensions. But from known cell dimensions, it looks like: 225.6*113.8*68 mm. So that is very small, even if compared to RC LiPo.

 

[999zip999]

I love the way you are working thru this.

 

[migueralliart]

I'm in it for the thrill...

Got 80 Samsung INR18650-25R's waiting for this

 

[docnjoj]

I am watching this thread carefully since I may go back to the Sony or other high quality cells and surely not having to risk soldering them would be super. Keep up the good work and sales will come.
otherDoc

 

[circuit]

Guys... Check this out. My cells arrived today.

Not welded up yet, as I still don't have enough tabs.
My tab material has also arrived last week. I have cut it to size and sent to manufacturer to machine the tabs. This first batch will be very expensive, but I hope it is worth it.

 

[crossbreak]

what is your tap material now? I wont have taken the steel i guess.. nickel?

 

[Twister]

Have you thought about 3D printing the trays? http://www.shapeways.com/shops/masterworks I think they do on line quotes if they are to expensive I know a few people with hobby printers.