Battery isn’t connecting to the motherboard

I’ve checked quite a few different boards and didn’t find anyone with this issue. My SP was working fine around a year ago, then after a year of sitting in the basement it would flash on for half a second then turn off, apparently a lot of things can cause this so but after buying a replacement battery and cleaning the motherboard with a toothbrush and rubbing alcohol I think I found the reason but I don’t know how to fix it

I’m not sure what this is called or how I can get it to stay in place again, but pet that should conduct the positive is loose, the rest of the motherboard seems fine

Thank you in advance if anyone knows how to help!