The iPhone XS and iPhone XS Max look exactly the same on the outside, but there’s a peculiar difference between them on the inside. iFixit took an X-ray of the pair and the iPhone X as part of its annual teardown and discovered something very interesting.
Turns out, the iPhone XS has a notch inside and outside. The former is obviously hidden, but you can see it clearly in the X-ray above (the iPhone XS is the one in the middle) within the single L-shaped battery. Apple has scooped out a chunk of the cell so there’s a circular cutout keeping it away from the nearest sharp corner.
Why The iPhone XS Has A Battery Notch
Apple hasn’t done this for style, but for practical purposes. The company actually filed for a patent related to this notch battery design way back in 2016, so it’s clearly put a lot of thought into this. iFixit explains that all lithium-polymer batteries need to have their corner sealed to stop undue stress from thermal expansion.
Most batteries have 4 sides, but the iPhone XS’ battery has 6 sides. Sealing those extra corners is very tricky as a result. Apple decided to cut out a portion of one of its corners to reduce stress and prevent any explosions, dubbing this the “relief zone” in its patent. Unfortunately, this also resulted in a reduced capacity compared to the iPhone X.
We recently found out that the iPhone X has a 2716mAh battery, the iPhone XS a 2658mAh one, and the iPhone XS Max a 3174mAh one. This change was very puzzling at first, but the X-rays now explain it. The iPhone X on the left and iPhone XS Max on the right both have two separate battery cells.
It’s not clear why Apple decided to implement this single battery in the iPhone XS and not the iPhone XS Max or iPhone X. Maybe it helps save up on space. In any case, the publication awarded the phones a reparability score of 6 out of 10, mostly because cracking the back glass requires the entire phone to be taken apart.