I've printed quite a few other single battery holders, but they were all subpar. Those with 3D springs either didn't have enough strength or weakened over time with use. Some used hardware that was hard/tricky to procure, especially if you only needed a few battery holders.

For this design, my goal is:

• It is possible to achieve strong electrical contact without the need for a spring.
• It's easy to assemble and there's no need to thread the wires through small holes.
• Use common and easily available hardware
• It is easy to print and customize, providing a battery holder that is suitable for all possible battery sizes.

You only need a few pieces of hardware:

• 2 nickel sheets with a width of 8 mm or 7 mm, cut to the required length
• 2 M3 nuts
• 2 M3 bolts, with a length of 10 mm to 15 mm would be more appropriate

When assembling, insert the nickel sheet into the wiring terminal board, then bend it towards the side with the protrusion

Now, after putting the battery into the battery holder, use a screwdriver to tighten one of the screws so that it makes good contact with the battery, and loosen it when needed. When tightening, the screw will push directly into the nickel plate part you inserted, so you can tighten it without worrying about damaging the fragile plastic parts.

After assembly, the nickel plate and the bolts are all connected to your battery, so you can use any of them. However, depending on the connection method, the nickel plate can carry more current.