Toyota Jidosha Kabushiki Kaisha

Kawada Industries, Inc.

Shigeyuki Kawatsu

Masayoshi Iwase

Seiji Mizuno

Hitoshi Hamada

Joji Yoshimura

Masayoshi Taki

An improved fuel cell makes uniform partial gas pressure of a fuel gas flowing through a gas passage formed between an electrode and a separator of a fuel cell, activating an electrode reaction in a whole region of the electrode surface along the gas passage. The inlet and outlet for the fuel gas are disposed on a diagonal line of the separator to define a gas passage such that fuel gas smoothly flows even though portions of the passage away from the diagonal line. This may reduce the separator size and improve the volumetric efficiency of the fuel cell and the diffusibility of fuel gas as well as the drainage of water produced by the electrode reaction.

Fuel cell and separator for the same

The structure of the present invention enables all catalysts packed in a cooling layer to be kept in an active temperature range, thereby sufficiently reducing the concentration of carbon monoxide included in a hydrogen-rich gas. A supply of water is fed through a water inlet pipe 40 to a selective CO oxidizing unit 34 of a reformer 30. The heat of vaporization of the supplied water directly cools down selective CO oxidizing catalysts 50 stored in the selective CO oxidizing unit 34. This enhances the cooling efficiency and enables all the selective CO oxidizing catalysts 50 stored in the selective CO oxidizing unit 34 to be maintained in the active temperature range, thus sufficiently reducing the concentration of carbon monoxide included in a resulting gaseous fuel.

Apparatus for and method of reducing concentration of carbon monoxide

A fuel-cells generator system of the present invention carries out an appropriate control to ensure a high output even when a catalyst carried on an electrode is poisoned. An electronic control unit of the fuel-cells generator system measures an output voltage E of fuel cells, a concentration D of carbon monoxide included in a gaseous fuel, a temperature T of the fuel cells, and a pressure P of the gaseous fuel at steps S100 through S130. When the output voltage E has been lowered by the amount of change that is not less than a predetermined voltage E0 at step S140 and when the concentration D of carbon monoxide measured by a carbon monoxide sensor represents the poisoned state of a catalyst carried on the anodes of the fuel cells at step S150, the temperature T of the fuel cells is gradually increased at step S180. The pressure P of the gaseous fuel is also gradually increased at step S190, in order to enable a partial vapor pressure in the gaseous fuel to be kept at a constant value even under the condition of the increased temperature of the fuel cells. This structure keeps the partial vapor pressure in the gaseous fuel at a constant level, thus preventing the partial pressure of hydrogen in the gaseous fuel from being lowered and ensuring a continuous supply of hydrogen to the anodes.

Fuel-cells generator system and method of generating electricity from

An apparatus or method of the present invention measures carbon monoxide included in a hydrogen-rich reactant gas with high precision, and also measures a lower alcohol or another organic compound included in the reactant gas. A carbon monoxide sensor (1) includes an electrolyte membrane (10), a pair of electrodes (12,14) arranged across the electrolyte membrane (10) to form a sandwich structure, a pair of holders (20,22) for supporting the sandwich structure as well as pair of metal plates (16,18), and an insulating member 24 for connecting the holders (20,22) with each other. A gas flow conduit (28) is joined with one holder (20), and a gaseous fuel is fed to the electrode (12) via the gas flow conduit (28). The electrode (14) supported by the other holder (22) is exposed to the atmosphere. A resistor (34) is connected to detection terminals (20T,22T) of the holders (20,22), and a potential difference between both terminals of the resistor (34) is measured with a voltmeter (32). The voltmeter (32) outputs a signal representing the measured potential difference to an external control system. The control system determines the degree of poisoning and the concentration of carbon monoxide, based on the signal representing the measured potential difference.

Apparatus for detecting carbon monoxide, organic compound, and lower

The present invention provides a fuel cell-based generator system that prevents a catalyst in fuel cells from being poisoned and a potential on oxygen electrodes of the fuel cells from lowering, while improving the energy efficiency. While I.sub.2 is fed from a halogen tank 41 to a preliminary reaction tank 30 via a first conduit 33, H.sub.2 O is fed from a water tank 43 to the preliminary reaction tank 30 via a second conduit 34. The preliminary reaction tank 30 is heated by the heat transmitted from a stack of fuel cells FC, and the reaction expressed as H.sub.2 O+I.sub.2 .fwdarw.2HI+(1/2)O.sub.2 occurs in the preliminary reaction tank 30. HI produced by the above reaction is dissolved in excess H.sub.2 O and fed into a reaction tank 50 via a fourth conduit 36. The reaction tank 50 is heated by the heat transmitted from the stack of fuel cells FC, and the reaction expressed as 2HI.fwdarw.H.sub.2 +I2 occurs in the reaction tank 50. The gaseous mixture of H.sub.2 and I.sub.2 is flown into a hydrogen purifier 60 via a sixth conduit 54. The hydrogen purifier 60 separates gaseous hydrogen H.sub.2 from the gaseous mixture. The gaseous hydrogen H.sub.2 is then fed into flows paths of gaseous hydrogen in the stack of fuel cells FC.

Fuel cell-based generator system and method of the same

The method of the present invention allows used electrolyte membranes to be easily recovered from fuel cells of relatively simple structure. A stack of polymer electrolyte fuel cells (10) is decomposed into unit cells (20), each unit cell (20) consisting of an electrolyte membrane 11 and electrodes (12,13). Each unit cell (20) is soaked in a soaking tank (51) filled with methanol and left for approximately ten minutes (see FIG. 5A). The soaking process substitutes water included in the electrolyte membrane (11) of the unit cell (20) by methanol and expands and deforms the electrolyte membrane (11), thereby dissolving a solid material caused by a proton-conductive polymer electrolyte solution working as an adhesive of joining the electrolyte membrane (11) with the electrodes (12,13). This weakens the adhesive forces at the interfaces between the electrolyte membrane (11) and the electrodes (12,13) and makes the electrolyte membrane (11) easily separable from the electrodes (12,13). After the electrolyte membrane (11) is separated from the electrodes (12,13) in a separation tank (53) (see FIG. 5B), the separated electrolyte membrane (11) is soaked in a substitution tank (55) filled with water (see FIG. 5C). Methanol included in the separated electrolyte membrane (11) is again substituted by water in the substitution tank (55). After the substitution, the electrolyte membrane (11) is placed in a wash tank (57) filled with aqueous hydrogen peroxide for cleaning (see FIG. 5D).

Method of recovering electrolyte membrane from fuel cell and apparatus

The fuel cell generator system of the present invention effectively cancels catalyst poisoning in fuel cells so as to improve the performance of fuel cells. In the fuel cell generator system of the invention, a carbon monoxide sensor is arranged in the middle of a gaseous fuel supply conduit, which connects fuel cells with a reformer for converting methanol and water to a hydrogen-rich gaseous fuel. An electronic control unit of the fuel cell generator system reads the carbon monoxide sensor to input a concentration of carbon monoxide D included in the gaseous fuel (step S250). When the carbon monoxide concentration D obtained is greater than a preset level D0, the electronic control unit increases the air flow fed to a partial oxidizing unit of the reformer (step S270). This accelerates the reaction in the partial oxidizing unit for oxidizing carbon monoxide to carbon dioxide, thereby lowering the concentration of carbon monoxide included in the gaseous fuel.

Fuel cell generator and method of the same

The invention definitely detects and cancels poisoning of a electrocatalyst in a fuel cell without delay. A first temperature sensor (61) and a second temperature sensor (63) are disposed respectively at an inlet and an outlet of first channels (34p) for gaseous fuel in a fuel cell (10). An electronic control unit (70) receives detection signals from the temperature sensors (61,63) and estimates a degree of poisoning of electrocatalyst on an anode (32) based on the detection signals. When determining that the electrocatalyst is poisoned, the electronic control unit (70) controls on and off first through fourth solenoid valves (51-54) to change the flow direction of the gaseous fuel through the first channels (34p). This allows a place with electrocatalyst poisoning to be exposed to the gaseous fuel having a relatively low concentration of carbon monoxide.

Growing community of inventors

Susono, Japan

Shigeyuki Kawatsu