I cleaned out my junk drawer. Big mistake. Now I have about a bijillion batteries rolling around that did not exist yesterday. Like any maker, I decided to spend an hour and a half designing, then 8 hours printing a solution to a 5-minute problem.
I searched around and did not find exactly what I wanted, so I created a new one. In case this one is not perfect for you, you can start with this and customize it in Tinkercad:
Battery_Tray.stl | 4.0MB |