https://motherboard.vice.com/en_us/article/vbnvpd/first-teardown-of-the-new-iphone-xs

Another year, another iPhone, and another iPhone teardown. Usually repair experts iFixit are the first to get hold of an iPhone and pull it apart before the internet, but this year Dutch YouTuber Fixjeiphone NL got hold of the new iPhone XS ahead of its release and busted it open for our benefit.

And the iPhone XS is a lot like the iPhone X internally. The seal that makes the XS waterproof and the battery seem to be the biggest differences. Fixjeiphone NL used a heat gun to loosen up the XS’ seal then pried it apart, but commented it was harder to pull the screen off than in previous models. Once inside, he revealed that the XS has one large L-shaped battery where the X has a two-cell batteries.