Hey everyone, first-time poster, long-time looker. I am deciding to continue my build I started a while ago, but I am getting to the battery and have some questions.
I am making a 12S 3P battery from 21700 cells, but I am running into a dilemma. How thin can I have my P group connections (I want copper, but I’m fine with nickel for the triangles of metal), and how should I connect my P groups together nicely while allowing for flexing of the battery pack (is soldering a thick wire to the triangle enough, or would that damage the batteries)?
If I have to stack nickel plates, how should I ensure that my series connection is connected well to all plates in the middle?
Each P group is going to be wrapped with Fish Paper (battery “O-rings” as well) and Kapton tape.
Huh, what’s the full layout of the pack? How is this p group oriented in relation to the others?
P45b? What’s your amperage goal for the build? 90a?
If you are doing copper connections how are you welding to the cell. Working on some methods to weld copper to cells and susing out some methods in another thread here : Spot welding copper stuffs
Yes, like mooch said but also to expand: work the building process to reduce heat input into the cells as much as possible in every step. Especially with copper - pre tining and soldering before attaching to the cells is important and worth the extra hassle and effort to protect the cells.
Really like the model you have there, looking clean so far. Makes my mocking up look like a crayon drawing
So 4 rows of three cell p groups? Make a crayon drawing or something, im not getting it sorry.
Im a visual learner, if you can show how theyre laying out in the pack we can help you figure the easiest best solution. With three cell groups in a half stagger there are quite a few different arrangements available to avoid bottlenecks in the series connections and i don’t wanna shoot you in the wrong direction
I have used the tab Fold over shoulder method twice now, but soldered after it is folded.
I use 0.5mm G10 fiberglass sheets between the tab and the double fishpapered cell, and can see no heat damage on the G10 when I remove it.
My concerns are that with copper’s great thermal conductivity, that soldering the series connections onto the tabs, introduces a more than deairable amount of heat into the cells, than would pure nickel.
The folded copper tins so easily, and I’ve only done dual 14awg series connections, but I want the copper splayed flat, and the curved tip ceramic tweezers are greT at this, but a third hand to feed the extra solder would be great.
To minimize heat entering the cell I attached a thermal pad to a heatsink, and clamp it to the p groups being soldered together.
