Battery charging holder

I am an electronics enthusiast and enjoy DIYing small devices. Recently, I've become fond of Li-ion charging. I found that I have chargers, but the batteries don't match, either too large or too small. So I considered a universal battery holder. This model uses an inverted buckle design, which can self-lock due to the elasticity of the electrodes, making it convenient to adjust for different batteries. An M3 brass screw is used for the positive electrode. For the negative electrode, a probe with an outer diameter of 3.2mm and a travel of 10mm is used. (Actually, if you don't have a probe, you can bend a brass sheet yourself and secure it with a screw). Just connect wires to both ends and link them to the charger. Electronic modifications require a certain level of hands-on ability and electrical safety knowledge. Please proceed according to your capabilities.