Patent attributes
A fuel cell system that employs a matched battery that matches the battery voltage to a fuel cell power bus voltage so as to eliminate the need for a DC/DC converter. The internal characteristics and parameters of the matched battery allow it to operate over the large load dependent voltage swing of the fuel cell, and prevent the battery state of charge from going below a damaging value. The battery type, number of battery cells and the battery internal impedance are selected to provide the desired matching. In one embodiment, the battery is a lithium ion battery. The system also includes a diode electrically coupled to the power bus line and a by-pass switch electrically coupled to the power bus line in parallel with the diode. The by-pass switch is selectively opened or closed to allow the fuel cell stack to recharge the battery and prevent the battery from being overcharged.
