It has been known for decades that electronic devices can be powered by batteries. Early electronic devices, such as transistor radios, were among the first such devices to be powered by batteries. Later electronic devices to be battery powered include dictation machines, CD players, portable computers, and even transportable medical equipment such as ambulatory heart monitors and defibrillators.
While the lack of intelligence of early electronic devices were a good match for the lack of intelligence of early batteries, the situation today is not so evenly matched. Electronic devices have gotten dramatically more intelligent, advanced and complicated over the years, while batteries have until recently stayed pretty much the same--dumb hunks of encased chemicals that provide power to just about anything hooked up between its contacts until the energy stored in the battery is depleted. An advancement was made when dumb batteries came in two styles--disposable and rechargeable--but being rechargeable didn't make the batteries any smarter.
While a dumb electronic device such as a transistor radio doesn't much care if it is powered by a dumb battery, smarter electronic devices such as computers and medical devices have a higher degree of dependence on a battery that can provide a known amount of power for a known amount of time in a reliable manner. When such smart electronic devices are hooked up to dumb batteries that can die without notice or warning, the operation of the electronic device itself can be undesirably uninterrupted. This interruption can range from annoying--as in the case of a portable computer whose battery unexpectedly dies while its user is composing the world's greatest novel, to deadly--as in the case of a transportable defibrillator whose battery dies during an attempt to resuscitate a patient whose heart is in ventricular fibrillation.
In the last couple of years, so-called "smart" batteries have arrived on the scene to partially address the above problem. These smart batteries, such as those described in the Intel/Duracell Smart Battery Specifications Manual, is defined as a battery pack that contains one or more of the following properties: chemistry self-identification, charge control, fuel gauging, or a communication port. These properties allow a smart electronic device to query the battery and find out what kind of battery it is and how much "fuel", or charge, it has left.
While smart batteries provide information that is helpful in avoiding some of the ways the operation of an electronic device can be interrupted due to unexpected battery failure, they only address a portion of the ways the operation of an electronic device can be interrupted due to unexpected battery failure. Specifically, smart batteries that are working as designed and intended can tell an electronic device in a fairly reliable manner how much power it has left. But smart batteries that are not operating in an expected manner, such as batteries that have been abused, are leaking, are out of calibration, or have an internal error such as a short or open circuit, cannot be trusted to give accurate information about themselves. In these cases, the battery may believe it has several minutes or hours of charge left when in fact it is dead or nearly dead. While this shortcoming of these smart batteries may be tolerable in electronic devices where unexpected battery failure is a simple annoyance, it cannot be tolerated in electronic devices where unexpected battery failure can result in the failure of a defibrillator to revive a patient whose heart is in ventricular fibrillation.