I can confirm that there are references to three new Smart Battery Case models that can be found inside iOS 13.1. The model codes are A2180, A2183 and A2184, presumably for the iPhone 11, iPhone 11 Pro, and iPhone 11 Pro Max, respectively.
Apple claims that its next generation iPhones offer significantly more battery life than the previous generation models. The iPhone 11 Pro is said to provide up to four more hours of battery life than the iPhone XS and the iPhone 11 Pro Max offers up to five more hours of usage than the iPhone XS Max.
If you still need the extra battery life offered by a Smart Battery Case, it's possible that Apple will release the cases before the holiday shopping season.
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