Would you look at that! The shiny copper from before is an inductive charging coil! (Maybe this'll catch on after all).

Quick inductive charging refresher: an inductive charging station drives an alternating current through a coil. The current moving back and forth in the base coil generates and collapses a magnetic field, which induces a current flow in the coil in the device. This AC current is then rectified into DC power to charge the battery.

Peeling the coil off lets us get a look at the 3.8 V, 3220 mAh (12.2 Wh) battery.

That's a step above the iPhone 6 Plus's 11.1 Wh, but it looks like the Nexus battery life doesn't benefit much.

For a "non-removable" battery, that wasn't so hard.