At the September ‘Special Event’ Apple unveiled the Apple Watch Series 5. The most notable new feature of the Apple Watch Series 5 is the addition of “always on display” feature. It required Apple to pack a larger battery as keeping the display on at all times draws a lot more energy.

So how did Apple pack a large battery without changing the dimensions (or increasing the size) of the Apple Watch? iFixit reports that the new 40mm Apple Watch’s battery uses a metal casing and not the usual black foil pouch found on almost every single Li-ion battery in the world.
Lithium-ion batteries are used in almost all electronic products like phones, laptops, smartwatches, etc. iFixit reports that by Apple using a metal casing and not the usual black foil pouch, it has been able to save some decent amount of space in the watch’s body.
The metal casing is apparently able to free up a good amount of space. Space in a small body such of a watch is to be used very carefully as smartwatches require many mini components to be packed while requiring a good battery backup. So it appears that using metal is a more efficient process compared to the other alternatives in the market.
Use the same materials in iPhones and MacBooks, please!
iFixit reports that it is not sure as to what the metal casing is made up of. It thinks it could be made up of aluminium, nickel, steel, or other alloys. If Apple could emulate the same process in its iPhones and MacBooks, it could be a huge win for the company.
Battery technology has not been improving on par with other technologies like the process, memory, or storage. So, it becomes extremely important for companies to pack larger batteries and one way to do so is by efficiently managing space.