• Just look at the inside any modern smartphone, it’s full of battery and other stuff, basically no empty space. The iPhone 7 was the first generation without a headphone jack, it still used the old case design though. Look at the iPhone X which was completely redesigned, it’s just marginally larger than the iPhone 6/6s/7/8 (they all use the same case design) but has a much larger battery. They went from 7.45Wh (1960mAh) on the iPhone 7

    to 10.35Wh (2716mAh) on the iPhone X.