Gotcha.... Hmmmm
I bet a little tin "Bridged clip" on the spring end would do it. I'll see what I can come up with, May be as simple as crimping a 1/8" wide strip of tin or very thin spring steel accross the contact end of the spring with a convex 3/32" dimple in the center... Gotta do some fiddlin' around with it.
Steve,
This is a simple cardboard strip as an example, But I think you'll understand what I'm talkin' about. You'd simply fold the ends under the top coil of the spring and crimp firmly and... WahLah! No more battery to spring contact issues to deal with.

Mike