This is definitely a revolution technology
This battery provides a drop in replacement for a regular 9 Volt battery and only weighs 23 grams when empty.
One downside however is that lithium polymer batteries are slightly temperamental. If the batter puffs up or appears bloated you should stop charging and properly recycle the battery as it is dead. You should only use a charger designed for lithium Polymer batteries, and preferably one with a built in cell balancer.
These cells are bloated and are now a fire hazard as lithium tends to react violently with air.
So each cell in the battery provides 3.7V and 380mAh but somehow the battery provides 9V and 450mAh. This is the power of Revolution Technology!
Actual specs are closer 8.4V peak voltage and 380mAh. I think the revolution has problems accurately rounding. On the upside your microcontroller's voltage regulator won't care that it is not getting 9 Volts.
Q1 appears to be a AO8822 Common-Drain Dual N-Channel Enhancement Mode Field Effect Transistor made by Alpha & Omega Semiconductor.
U1 has 6 pins and is labeled with part code PAL.
This particular battery seems to have died due to a short between pin 1 and pin 2,3. Sparkfun is awesome and sent me out a replacement with any hassles.