Hey there @wingman4l7,
iFixit recently put out a [link|https://www.ifixit.com/News/95474/rabbit-r1-and-humane-ai-pin-teardown-the-beginning-of-a-new-device-category|teardown for the R1 and the Humane AI Pin|new_window=true]. The battery itself is connected to the R1's motherboard with a [guide|25629|press connector|stepid=70308|new_window=true], which shouldn't require any soldering to remove, but you will need a heating pad, and an opening pick or jimmy to get into the R1.
But to answer your question, you could upgrade your R1 with one with a higher Watt-hour battery, provided it has the same voltage output, 0.5mA recharge, and it is compatible with the connection on your R1's motherboard.
Try and think of it like upgrading the fuel tank in a car to a larger one. It should work as long as you don't change the type of fuel, and the tank fits properly in your car.
Hope this was helpful!