The 40mm Apple Watch Series 5 has a strange new battery design

The tinkerers at iFixit have been digging inside the new versions of the Apple Watch, and have made an interesting discovery. While the 44mm Apple Watch Series 5 contained “only a handful of minor differences from last year’s Series 4,” the 40mm edition has a radical new battery design.

With most lithium-ion batteries, iFixit is used to finding a foil pouch for the battery to live in, but with the 40mm Apple Watch Series 5, the company found a “snazzy new metal casing,” which is speculates is made of aluminium. 

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The question is why? iFixit speculates that it’s the first time this Apple patent has been seen out in the wild, and if that’s the case then firstly, it’s more efficient. It’s apparently capable of increasing the battery capacity in the same space thanks to the absence of a large seal on the foil pouches of previous versions.  

For Apple, that’s probably the key reason, but for others – especially those with a keen interest in repairability like iFixit – it’s only a minor plus. Another thing highlighted in the patent is that it makes the battery physically stronger, and less likely to be punctured during repairs. The patent also states that metal casing means a battery can be screwed down, which again would be a boon for repairers, though in the case of the new Apple Watch it still uses the traditional repair-unfriendly glue. 

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Provided the 40mm model doesn’t have a spate of battery-related returns, this can only be a good thing. The only question left is why is the 40mm model the sole beneficiary? The site speculates that it might be a small-scale test to make sure everything runs as expected before rolling out further. Alternatively, it might just be that the 40mm model needed the battery-life boost more than its 44mm sibling. Either way, it’s an interesting development which could transform the repairability rating of Apple products going forwards.