This layout has a nickel strip for each cell. If you add one piece of copper to the middle, withe there being only one cell to either side, the max current each line of nickel will carry is 30a. The path would be longer for the cells on the left and right, so over time the center cell will see more of the demand and wear out faster. Maybe not enough though to make any practical difference.
Personally I donāt like the way nickel sticks to nickel spot welded, and try to stay away from stacking. Whatever conductor you add, think about which way electricity flows from group to group. With only one series connection between groups, the parallel connections will have significant current passing through. If you make a series connection one per cell, the parallel connections will have negligent current.
In theory we would want all connections to be copper. We use nickel for reducing heat to cells, and convenience.
If youāre soldering one wire, soldering more wires in the same way should not be more harmful.
Typically we solder wire onto nickel between cells to reduce heating of cells.
So, ideally for electrocity, one wire per cell. But for reducing heating effects, one wire between each pair of cells.
Or stack copper across the whole nickel strip then do series copper however you like.
Disclaimer: This is all my opinion, and everyone chooses different trade-offs. I think for a normal urethane board, itās hard to pull more than 60-70 amps from a pack. Me, for high current packs I use lots of copper.
Guys, i finally pulled the trigger to create a diy battery pack, i am getting the 10s4p battery ready, should i surround the positive and negative pole with kapton tape?
Thanks for the tips!!! Will do that once I find them, does anybody here know where to buy fish paper in europe? Nkon doesnāt have stock unfortunately
I was about to solder the serial connections on my battery pack and use a new soldering tin which seems to have a lot of Kolophonium/flux inside:
It produces a brown/yellow residue. The tin looks silver and shiny which is good but could this flux later be a problem or am I good to contiue soldering?
Edit: I can clean it off with 2-propanol
Iām getting ready to make a 12s6p battery, and I made a 3d model to try and show my proposed layout to get some feedback on it:
Each part of the 12 series is a collection of 6 cells, connected together in parallel in a 2x3 config. The series snakes out and back from the terminals. Each series in upside down of the one before it so that nickel strips can be welded on from one series straight across to the next one. The squares on top of the pack represent where the strips are connecting series together. It might be hard to see, but there are some on the bottom of the pack as well that continue the snaking pattern.
The primary goal of this layout is to eliminate any head to toe connections that would result in nickel strips being bend.
All connections will be made with a spot welder, and the terminal leads will be soldered onto the nickel strips before being welded to the pack.
Also! Iām planning on drawing 100 amps from this 12s pack. And want to make sure I have enough layers of nickel. My strips are 8mm x 0.15mm for a cross-section of 1.2mmĀ² per layer of nickel. I plan on making āladdersā on positive an negative terminals of each of the 12 segments like this:
For the parallel connections, it should be enough from what Iāve heard. I used wayyy more in my pack but other people havenāt had issues with how much you are using.
For the series connections, I would probably skip the nickel strip and only use braided copper wire. Donāt know if itās true that it can do 32A, but if so, it should be enough while still keeping some flex in the battery.
You could also use copper strip. I have heard it should be pretty good and can draw a lot of amps (more than 100A)
Looking over some of the ampacity charts Iāve always noticed that copper is lower resistance, thereby able to handle more current before getting hot.
Why donāt we all just use copper instead of nickel?
Yeah this is basically identical to my first config idea! I originally thought of 6x1 grouping similar to your 7x1 but lately Iāve been leaning towards 3x2 because that way I can have the overall positive and negative terminals next to each other rather than on opposite ends of my pelican case