In past years, a battery case was almost a necessity if you owned an iPhone. This year, however, Apple went out of its way to make the iPhone 11 lineup thicker so that it could add higher capacity batteries to each of the devices. In fact, battery life is so good on the new iPhones, you may not need or want to buy a battery case.
9to5 wasn't able to find out how much battery life the cases will add to each iPhone, nor when Apple will release them. However, the website speculates Apple may announce the new case, alongside its long-rumored tracking tags, later this year. The company did something similar this past March when it launched the second-generation AirPods, 10.5-inch iPad Air and 2019 iPad mini all in the same week.