The Pimoroni Tufty 2040 Badge + Accessory Kit doesn't have a good solution for securing the battery case beyond some velcro stickers. There is a great model designed for semi-permanent storage of one of the LiPo battery packs (but lacking a charger, you're going to be opening the case often.
Assembly:
Enjoy!
Thanks Les Pounder for your work on the original model!
The author remixed this model.