“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.”