Some interesting information from the BlackBerry Dev Blog sent in by Tee. NFC-enabled BlackBerry smartphone devices may be able to process NFC transactions, such as payments, even when they have a dead battery? Smartphones which support NFC will continue to be able to provide NFC card emulation functionality when in “low battery mode” or, in some circumstances, even when the battery is completely dead.
Low battery mode starts when the smartphone OS turns off the user interface due to the battery being deemed “low”. The smartphone appears to be off to the user, but internally, the Power Management Integrated Circuit (PMIC) is still on. Dead battery mode, by way of contrast, starts when there is no longer enough power in the battery to keep even the PMIC powered on.