I did. It is very difficult to open without doing any damage. I ended up prying in the wrong spot to remove the circuitboard and destroyed my controls on the right earbud. Patience is required with this repair.
Replacing the battery requires heat, and soldering/desoldering. I plan on fixing mine either today or tomorrow. There is a good tutorial on YouTube. You have to make sure you get the battery for the Soundsport Free Wireless, not the Soundsport Free. They aren’t interchangeable as far as I’ve found.
I had a similar problem and the temperature gauge spiked all of a sudden. Check your cabin air filters. (Behind the glove box.) Mine were caked with dirt, leaves and junk. I replaced one cooling fan that wasn’t coming on and also the thermostat. Those three things got the A/C and cooling working for me. 245,000 miles and just had the refrigerant refilled.
We missed the window for Apple’s battery replacement so I finally bought a replacement here. Great tutorial. Easy to follow steps (wow, those screws are small!) All replaced and reassembled with no parts left over. :)