To optimize the battery, the screen could darken or brighten and the CPU clock speed could change. While current battery conserving programs wait until the battery is almost dead to implement certain changes to make the remaining battery life stretch out as long as possible, the patent would allow for longer term battery power budgeting so that the battery could last throughout a specific time period.
In one example listed in the patent, an iPhone user puts his phone in Airplane mode on a jetliner. The phone communicates using an API with a program (like eWallet or the calendar, to determine the length of the flight. The phone would then automatically adjust the performance of a couple of programs to ensure that the battery could last the entire flight without charging. Pretty cool, huh?
Another example would be the use of eWallet to purchase a drink at a coffee house. Knowing that you will be getting your caffeine fix for the next 20 to 30 minutes, and that you probably will be playing games during that period of time, the system could spring into action making sure "it is in the user's best interest to sacrifice some battery life in favor of improved performance."
Apple's patent application would allow for long-term budgeting of the battery on the Apple iPhone
source: USPTO via AppleInsider, Engadget