The MagSafe ring and magnetic car mounts

I've been trying to find out exactly how the magnetic charging works and how it works in the MagSafe world. Everything I find just describes how it works with the accessories, the fact that it charges wirelessly, etc. I understand there is a coil in the phone and an equivalent one in the charger - as pictured in this article: https://www.macworld.com/article/671596/complete-guide-to-apple-magsafe-what-is-magsafe.html

what I'm trying to figure out is if the rings in the cases that work with MagSafe have some kind of wire in them that helps as a go-between for the phone and charger b/c none of them seem to be magnetic. I assume SOMETHING is in that white ring they have on them. Along with that, is the charging happening between the ring (as shown on cases) and an identically-sized ring in the phone, or is that phone coil (like pictured in the link above) much bigger. Reason I'm asking is that I have an existing magnetic car mount that is very good, and was wondering if I can put the receiving metal plate on my case inside that ring to use when I'm in the car. If I put that metal plate there will it block the wireless charging signal (meaning area inside that ring is being used) or will it not?

Thanks for any technical info anyone has.