This is an idea I came up with while I was making my previous Instructable. As I mentioned in there, my first version of the project did not work out very well at all, partially because I didn't have a proper battery holder. This simple, effortless idea would have helped me a lot.

Step 1: Supplies

All you need to make this is

Battery
Packaging of the battery
Thick aluminium foil (I got it from a disposable food tray)
Glue (optional)
Scissors

Step 2: Connections

To make your battery holder, unwrap the battery by hand, to avoid damage to the plastic cover.
Then, take the strips of foil and cut them down so that they fit in the cover. Fold the foil several times, to make it thicker. Then fold it around the outside of the cover, as shown above. If you want the foil connection to stick, glueing it into the cover might be a good idea.

Step 3: Test

Once everything is connected, test it out. Connect some crocodile clips and a lightbulb or a simple circuit or a motor to it. If it doesn't work, your foil might not be conductive (there might be a insulating layer over it, which you could easily sand off), or your connections are somehow wrong. Or maybe it's the battery.

And that's pretty much all there is to it. This concept can be applied to almost any type of battery, as long as you keep the packaging. I didn't have any other battery packages, so I couldn't make any more battery holders, but I'll make more and upload more photos as soon as I get the chance.

Please comment for any suggestions/improvements/questions, andIf you'd like a Pro Membership, post photos of your adaptions and uses of the battery holder below.