Abstract:
A fuel cell system employs at least two fuel cell stacks electrically coupled in parallel to reduce the load turndown ratio of the fuel cell stacks. Fewer than all fuel cell stacks may be operated where the power demand permits. An oxidant supply subsystem may cease supplying oxidant to one of the fuel cell stacks to stop operation (power production) from the fuel cell stack. The fuel cell stacks may take turns at being the non-operating fuel cell stack.
Abstract:
A fuel cell system according to the invention includes: a detecting unit (6, 12) that detects an operation parameter of the fuel cell; an internal resistance estimating unit (20) that sets the internal resistance of the fuel cell a basic internal resistance; a flow rate measuring unit (3) that measures the airflow rate; a pressure measuring unit (4) that measures the air pressure; a determining unit (20) that determines the IR-free output characteristic of the fuel cell; a setting unit (20) that sets the basic output characteristic of the fuel cell; an output current measuring unit (8) that measures the output current of the fuel cell; an output voltage measuring unit (9) that measures the output voltage of the fuel cell; and a calculating unit (20) that corrects the basic output characteristic using the output current and the output voltage.
Abstract:
A system for and method of electrochemical testing of fuel cells, such as solid membrane fuel cells, is presented. The system and method allow for non-destructive testing of one or more solid membrane fuel cells. In particular, the system and method allow for testing a working first fuel cell in a testing fixture. The first fuel cell may be removed from the testing fixture without substantial damage to the first fuel cell and replaced by a second fuel cell. The second fuel cell may be electrochemically tested, removed without substantially damaging it, and the process repeated with additional fuel cells.
Abstract:
A fuel cell system employs at least two fuel cell stacks electrically coupled in parallel to reduce the load turndown ratio of the fuel cell stacks. Fewer than all fuel cell stacks may be operated where the power demand permits. An oxidant supply subsystem may cease supplying oxidant to one of the fuel cell stacks to stop operation (power production) from the fuel cell stack. The fuel cell stacks may take turns at being the non-operating fuel cell stack.
Abstract:
Radio frequency identification (RFID) devices may be used to monitor various operating parameters in fuel cells. For example, RFID devices may be used to monitor the voltage of individual cells in a fuel cell stack and thus to check for voltage reversal conditions during stack operation.
Abstract:
Durability of a fuel cell sometimes decreases due to deterioration of the catalyst when the fuel cell is stored for a long time. Disclosed is a fuel cell system comprising a stack (38) for generating electric power from a fuel gas and an oxidant, a fuel gas supplying means, an oxidant gas supplying means, a raw material gas supplying means including a raw material gas piping (33), a bypass pipe (55) and distributors (56, 60) for supplying a raw material of the fuel gas to a fuel cell, and a control unit (44). After power output of the fuel cell is turned off, the fuel gas supplying means stops supplying the fuel gas to the anode side of the fuel cell and the oxidant gas supplying means stops supplying the oxidant to the cathode side of the fuel cell, while the raw material gas supplying means supplies the raw material from the input side of the cathode of the fuel cell, thereby purging the cathode side of the fuel fell.
Abstract:
A power system with a fuel cell array (4) is integrated with power, conversion and control circuitry (6, 8) forming an assembly on a single chip (2). The power system may include mounted discrete components or flip chips. The power transistors (10) may be built with contacts on both top and bottom of the chip, where the large area on the bottom allows for high power dissipation and current densities. Electrical connections are made between the components by etched runs or integrated layers, as is typically found in integrated circuits. The control functions include controlling the gas flowing in the fuel cell channels in response to the power supplied. Temperature and pressure may be measured and used to optimize the power system operation.
Abstract:
A fuel cell power plant comprises a fuel cell stack (1) constituted by aplurality of fuel cells which perform electric power generation by means of areaction of hydrogen and oxygen. A controller (16) determines whether or notmoisture inside the fuel cell stack (1) is frozen, and if the moisture is frozen,the controller (16) causes the fuel cell stack (1) to perform intermittent electricpower generation via an inverter (27) while continuing to supply oxygen to thefuel cell stack (1). The fuel cell stack (1) generates heat as a result of theelectric power generation, whereby moisture is generated in a cathode (9).During the periods in which electric power generation is not performed, theoxygen which is supplied to the cathode (9) of the fuel cells scavenges thegenerated moisture, thereby ensuring the supply of oxygen to the cathode (9)during electric power generation.
Abstract:
A method of operating a polymer electrolytic fuel cell, wherein its operating condition is regulated for an optimal one which is represented by a function of a gas flow rate and the difference between a saturated steam pressure and an actual steam pressure, by regulating an in-plane temperature distribution obtained by a cooling water flow direction and by the regulations of a cooling water inlet temperature and a cooling water flow rate, a gas supply amount, and a supplied moisture amount, and a current density, the method resolving conventional problems with a polymer electrolytic fuel cell that a performance distribution occurs in a single plane of a cell and a stable operation is difficult when a performance distribution is significant.