The problem with lithium-ion batteries used in our smartphones is that they have a finite number of cycles before they stop being as efficient as they were brand new out of the box. These cycles are essentially the number of times they are fully charged from 0-100, which counts as a single cycle.
However, it seems that Google is trying to address that because in a quiet update that was pushed out to Pixel owners, Google has introduced a new feature that can stop the Pixel while it is charging at 80%. This means that because the battery hasn’t hit 100% yet, it doesn’t count as a full cycle, so in theory your battery should last longer.
If this sounds familiar, it is because Apple has a similar feature for the iPhone in the form of “optimized battery charging”. However, in Apple’s case, it is something that users can enable or disable, but in the Pixel’s case, it seems to be automatic. According to a Google support page, it says that the feature will be automatically enabled when your phone is under “Continuous charge under high battery drain conditions, like game play,” or it is under “Continuous charge for 4 days or more.”
It seems a bit more aggressive compared to the iOS version, but that’s not a bad thing since battery efficiency is usually one of the first things to go as a phone starts to age, so maybe this will help users keep their phones around for longer.