"Battery Health" in macOS Catalina 10.15.5? I have just installed the macOS Catalina 10.15.5 update on my 11" Mid 2013 MacBook Air. The update is working fine.

The MacBook Air specifications on the Wikipedia page says that this model has a lithium-ion battery, 'tho I haven't unscrewed the case to look. But the new Battery Health controls in System Preferences → Energy Saver don't appear.

Not a lithium-ion battery? Or perhaps other differences in this model prevent Battery Health from showing up? Something else?
The feature is limited to Mac laptops with Thunderbolt 3 ports. While this isn't explicitly mentioned in the macOS 10.15.5 release notes issued by Apple, here's an article by The Verge mentioning it:


https://www.theverge.com/2020/5/26/21271179/macos-10-15-5-catalina-battery-health-group-facetime-portrait



  The new battery health feature will be turned on by default for new MacBooks that ship with macOS 10.15.5 or after you upgrade to macOS 10.15.5 if you’re using a MacBook that supports Thunderbolt 3 (which is any MacBook Pro released in 2016 or later or any MacBook Air released in 2018 or later).




The Battery health feature released in macOS Catalina 10.15.5 can be access by going to System Preferences app → Energy Saver and clicking the Battery Health... button. It is turned on by default.





You can learn more about by going to this Apple Support article:


https://support.apple.com/kb/HT211094


Here's a list of all the current Apple laptops that have the Battery Health feature available:

MacBook Air


MacBook Air (Retina, 13-inch, Late 2018)
MacBook Air (Retina, 13-inch, Mid 2019)
MacBook Air (Retina, 13-inch, Early 2020)


MacBook Pro


MacBook Pro (13-inch, Late 2016, Two Thunderbolt 3 Ports)
MacBook Pro (13-inch, Late 2016, Four Thunderbolt 3 Ports)
MacBook Pro (15-inch, Late 2016)
MacBook Pro (13-inch, Mid 2017, Two Thunderbolt 3 Ports)
MacBook Pro (13-inch, Mid 2017, Four Thunderbolt 3 Ports)
MacBook Pro (15-inch, Mid 2017)
MacBook Pro (13-inch, Mid 2018, Four Thunderbolt 3 Ports)
MacBook Pro (15-inch, Mid 2018)
MacBook Pro (13-inch, Mid 2019, Two Thunderbolt 3 Ports)
MacBook Pro (13-inch, Mid 2019, Four Thunderbolt 3 Ports)
MacBook Pro (15-inch, Mid 2019)
MacBook Pro (16-inch, Late 2019)
MacBook Pro (13-inch, Mid 2020, Two Thunderbolt 3 Ports)
MacBook Pro (13-inch, Mid 2020, Four Thunderbolt 3 Ports)