Apple has released a number of SMC firmware updates for its line of MacBooks, starting with the mid-2012 models through to its latest mid-2013 models. This includes the MacBook Pro, the MacBook Pro with Retina Display, and the MacBook Air.
The updates address problems specific to battery function, where systems may stop responding when the battery charge gets low, or the battery simply stops providing power.
If you have one of the affected systems you should be able to get the relevant update through Software Update in the Apple menu. The updates can also be downloaded from the following Apple support pages:
The updates will have instructions for how to properly apply them, which essentially amounts to making sure your system is plugged into a reliable power source for the update, and not interrupting the update progress. The system will reboot to a small progress bar, and then may reboot one or two more times when updating, and then should return to normal operation.
As always, be sure to fully back up your system before applying these or any other updates.