Parametric 18650 battery grid

This is a rewrite of the 18650 single battery holder by digitalkiwi in OpenSCAD so it is fully parametric. Cell grids of any size can be defined. Grids interlock together easily to create large battery packs.

There is an option to omit the restraining tabs which is useful for the negative side of the battery so defective cells can be easily pushed out of the pack, and there is a slot provided so cable ties can be used to clamp the pack together, or to restrain the busbar.

STL files have been provided of a selection of grid sizes.