The battery in an Apple Watch 2 can fail, and even swell up. This is a rare problem, but Apple will fix the watch if it occurs. Swelling is a problem that has long plagued lithium-ion batteries from laptops, phones, and other electronics. The only fix is a replacement of the battery. Apple alerted its
Apple Watch 2 Swollen? You Can Get a Free Fix
Apple Watch Series 2 devices are having some problems. And Apple will fix them.