Yeah, I've made a few similar to that myself (of aluminum) I guess I'd ideally have something that surrounds the entire battery (bottom, and all four sides) and ideally a non-conductive material. Basically the delrin or other plastic trays are perfect. The aluminum definitely works... but the more wrapped around and the less conductive the better..
but definitely thank you for the tip. I like your design. I just may end up using it. Thanks!
Now that I think about it - duh - you can line it with a a plastic or foam material to make it non-conductive. Some padding would be a great idea anyway. Maybe I'll go with a custom aluminum one.
Anyone know where to get some adhesive foam? Like double stick foam tape - but thicker and only one adhesive side.