Best connection practice between wire and nickel strip.

[Lewp91]

Currently remaking two 20s5p vtc6 packs I run in parallel to create 20s10p. (Removed all the original nickel strips to replace.)

The pack is based around trapezoidal 5p groups all hot glued together, I could rearrange the pack but don't see the need unless someone tells me otherwise.









Plan is:
Series connections, triple layer 0.15*8mm full lengths. Parallel; single zig zag'd 0.15*8mm.

The packs should be capable of 150a pulse each with a continuous around 75-100a each.

I have a BMS's rated to 60a output each, but bypass them when I'm demanding big power.

The previous connections (about half inch of striped turnology 10awg high strand silicone insulated cable soldered over the last cell's nickel strip) didn't seem like they were up for the job.

Ill possibly go to 8 or 6awg next, but it's the attachment of said wire that has me uncertain.

My current idea is to split the thick gauge wire and silver solder it to the nickel Strips across the 3 and 2 cell rows of the parallel group.



But I'm not fond of heating cells with a 80/100w soldering iron.

What other ways could I do it? Or better yet what's the best way of doing it?

 

[flippy]

you should have extented the nickel strips to fold them 90 degrees and overlay them and spot weld those together so you have a thick and wide tab next to the cells. that tab you can solder the wite on both sides and then fold it flat. (after applying liberal layers of kapton between the tab and cell walls to prevent any chance of a short between the wire and cell walls it might rub against)

 

[Lewp91]

you should have extented the nickel strips to fold them 90 degrees and overlay them and spot weld those together so you have a thick and wide tab next to the cells. that tab you can solder the wite on both sides and then fold it flat. (after applying liberal layers of kapton between the tab and cell walls to prevent any chance of a short between the wire and cell walls it might rub against)

I've removed all the strips seen in the previous photos so I'm open to options.

Do you mean like this or this?





Would you have any photos of designs like this? I'm currently traveling though the site on the lookout.

Thanks.

 

[flippy]

yes, that is roughly what i mean.

but use a SINGLE long strips that starts at the back cell and end at the spot were you solder on the wire.

see the attachement for a more simple layout.
(yes, i had issues with my welder at the time so please ignore the spot welds, this was a prototype)

once you have the strips sticking out you can fold them 90 degrees so you get a nice tab (after trimming the exess) you can spot weld or solder it into a thick pack and solder on wires.

also note that the SERIES strips are done first and then only a single parralel one because that one only has to balance the series cells.

 

[Lewp91]

Thanks for the photo, is there a reason that there are gaps between the edge series strips and the parallel strips?

Would it be better to reconfigure my layout out of a 5p clusters and into 5p rows?

 

[flippy]

what gaps do you mean exactly?
note that in this picture i am not finished welding.


and yes, if you can make the connections more parralel (as shown in my example) it would mean you can make lots of series connections that actually carry the current and you only need a small strip to balance the group.

i will see if i can find a pic of a finished tab.

 

[Lewp91]

I was looking at your layout wrong there are no gaps thanks,

I'll be disassembling and remaking my packs.