18650 snap-together tower of power (2,4,5,6 cell options)

thingiverse

Stackable and Snapable 18650 Battery Case: A DIY Solution for Variable-Voltage Packs Without Soldering or Grinding Building a high-voltage battery pack from reclaimed laptop cells can be a daunting task. Traditional solutions require soldering, spot welding, or elaborate enclosures that make cell replacement difficult. However, with the right design, you can create a stackable and snapable 18650 battery case that makes it easy to swap out individual cells without heating them up or grinding off nickel strip residue. My solution is inspired by enif's excellent 18650 battery case with built-in spring. I've made some tweaks to allow for individual cell replacement while avoiding the need for soldering and grinding. This design also allows for extendable voltage packs, making it a cheap and efficient solution for powering your ebike or other applications. To build this stackable battery pack, you'll need some basic materials: 12ga stranded wire, 8mm M3 grub screws, and optional 10mm pan-head M3 screws. You can use Tinkercad to slice up the STL file and add more cell slots if needed. I printed my design at a 0.3mm resolution using PLA. Depending on your printer's calibration, you may need to scale the STL file up or down by 1-2%. The interconnect wire is 12ga stranded, with its insulation sliced to expose half of the wire for the length of the battery case. The current model's wire holes are too small for 12ga wire, but I've drilled them out to fit. M3 grub screws hold the batteries tight and squish the wire against the battery terminals. The battery modules stack front-to-back, allowing wire to loop from the + end of one set to the - of another. If the modules don't snap together firmly enough for you, there are aligned holes for M3 pan-head screws to snug things together. This design isn't the most efficient in terms of power-to-volume ratio, but it'll work well enough for my ebike application. As I haven't used these battery packs in their intended application yet, I'm planning to build another stack to attach in parallel to the first. This should double my range and halve the amp draw on each set. Future improvements include a jig to make cutting the insulation off the wire easier, a flap to spread the load from the single grub screw point across the entire wire, snap-on fan mounts for cooling fans, or even making these improvements myself. Get the latest version of this design at https://www.tinkercad.com/things/4mitzZL41nM-18650x4-snap-case-12ga-wire-v81.