Find and extract a Philips screw at bottom of the device.

Slide PCB and battery out of the enclosure by pulling on the lens at the front of the device.

Un-clip the plastic lens from the black plastic clip and PCB.

Remove Philips screws from black plastic clip and carefully remove the PCB from the plastic.

Carefully peel battery away from the PCB by breaking the adhesive. After repair the battery will barely stick to the adhesive but the enclosure can still hold the battery in place. The ruined adhesive could be replaced with new adhesive if desired.

The yellow tape may be removed from the battery and the voltage regulation PCB can be bent away from the battery in order to access the voltage regulation chip and constant current LED driver chip for repair. Solder rework can be done here after detaching (de-soldering) the battery.