During our exploration of e-textiles tools of desire we realised that wig clips make for great coin cell battery holders. They are sewable and come with a bit of silicon that insulates the back. To make them fully function as e-textile components just attach a bit of fabric or thread to the middle of the back. The metal part of the clip becomes your +3V, the back bit becomes the GND.
Here’s a pic of our jazzed up battery holder with crystals grown on the top.