Weld-Less 18650 Battery Build System

thingiverse

This is a weld-less battery build system for 18650 lithium cells. It is designed to press standard nickel strips (usually welded to the cells) against the cell ends to make contact. The cell holders should be clamped together via two pieces of plywood and #8 screws every two cells, to ensure even clamping pressure. To maintain proper tension, one side uses 6mm silicone bumpers (meant for cabinet doors) to act as mini springs (see link). https://www.amazon.com/gp/product/B073SVKFYJ/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&th=1 The holders are designed to be built in 2 or 3 cells wide strips for the series direction, and in the full length for the parallel as nickel strips are much more forgiving with sideways spacing than lengthwise. The idea is you'd use 2x strips with a single 3x at the end if your number of cells in series is odd. Also included are partial length strips if your printer isn't large enough for the size you want. I've included sizes from 2P up to 17P (the largest size my printer can handle diagonally) but you can use the partial strips to go longer. If requested I will add more sizes. I suggest a higher temperature resistance filament like PETG in case the battery heats up more than PLA can handle. These parts are designed around a wall thickness of 1.567mm so using a line width that goes into that evenly works well (0.522mm for a 0.4mm nozzle, or 0.784mm for a 0.6 mm one). Choose a high enough number of walls such that there is no infill. CNC Kitchen had a video suggesting to not exceed a layer height of 50% of the nozzle diameter for maximum strength. A 0.6mm thick bottom helps adhesion with printers that have slightly warped beds so a raft is unnecessary. This is a work in progress, as I am still in the process of building my battery (14S 17P) to yield test data and to provide pictures for a detailed build document. However, if you want to give it a try I'd be happy to provide some assistance before then, just send me a PM! Update 1/11/2022: Here is a rough assembly overview. Please feel free to ask for clarification. https://docs.google.com/document/d/1ULGGwMUAA4q4Hu8wWYp6rgAzXi1gr_jD-B5jXYOl3VI/edit?usp=sharing Update: 3/20/2022: Got my first test battery using the system assembled (a 14s x 17p one). Went well, but I learned a few things that have made me consider a new direction for weld-less systems. Stay tuned! Update 4/6/2002: Had a request for a step version of the 7s14p size, so added them.