Flexing battery holders with integrated spring

For my electronic projects I often need battery holders of various size and for different number of cells: single, multiple cells in parallel or in series, or serial lithium-ion type cells with connectors for balanced charging between the cells.

So the project here was to generate fully parametrized, printable battery holders for cylindrical cells of arbitrary size and number. The additional challenge for me was to have the battery sit firmly in the holder without the use of the metallic spring that is usually found at the minus pole. In this design the metallic spring is replaced by a flexible printed curled structure, which presses the contacts firmly to the battery. This plastic spring flexes about 1 - 2mm, which is just what's needed to comfortably insert and remove the cells.



The contacts for the plus and minus pole can easily be made by a few windings of the uninsulated ends of the connecting wires. Each battery compartment contains are several holes to the outside as well ad to the neighboring compartments, through which connecting wires can be passed for easy configuring of parallel, serial or balanced-serial battery packs. Also, on the bottom of the case, there are longitudinal and traversal wire channels, which can be used for assing wires outside the case.


Given that the printed plastic spring needs to be flexible, ABS is the material of choice here. Also, I use a some "ABS slur" (mixture of ABS and acetone) to cover and…