Panasonic Corporation

Matsushita Electric Industrial Co., Ltd.

The Penn State Research Foundation

Hideyuki Ueda

Masaru Odagiri

Mikio Murai

Takashi Akiyama

Kenji Kuwahara

Kiyoshi Takahashi

Hiroshi Seki

Shinsuke Fukuda

Hiroaki Matsuda

Kiyosi Takahasi

Yukihiro Okada

Masahiro Takada

Kohji Yuasa

Satoshi Shibutani

Yukikazu Ohchi

Sadayuki Okazaki

Chao-Yang Wang

Tatsuya Hiwatashi

Noriyasu Echigo

Toshihiko Ichinose

Disclosed is a membrane electrode assembly for a fuel cell including an anode, a cathode, and an electrolyte membrane disposed therebetween. The anode includes an anode catalyst layer laminated on one principal surface of the electrolyte membrane, and an anode diffusion layer laminated on the anode catalyst layer. The cathode includes a cathode catalyst layer laminated on the other principal surface of the electrolyte membrane, and a cathode diffusion layer laminated on the cathode catalyst layer. At least one of the anode and cathode diffusion layers includes a conductive porous substrate, a porous composite layer laminated on the conductive porous substrate at the catalyst layer side, and a modified layer disposed on the porous composite layer at the catalyst layer side. The porous composite layer includes a conductive carbon material, and a first water-repellent resin material. The modified layer includes a second water-repellent resin material having a needle-like shape.

Membrane electrode assembly for fuel cell and fuel cell using the same

A membrane-electrode assembly for a direct oxidation fuel cell includes an electrolyte membrane, and an anode and a cathode sandwiching said electrolyte membrane. The cathode includes a catalyst layer in contact with the electrolyte membrane and a diffusion layer formed on the catalyst layer, and the catalyst layer contains 2 to 20% by volume of pores. A direct oxidation fuel cell including this membrane-electrode assembly has excellent power generating performance and durability.

Membrane-electrode assembly for direct oxidation fuel cell and direct oxidation fuel cell

A method for activating a direct oxidation fuel cell including an anode, a cathode, and a proton-conductive electrolyte membrane interposed between the anode and the cathode is provided. The anode and the cathode each have a catalyst layer on a face in contact with the proton-conductive electrolyte membrane. This method activates the fuel cell by passing a current through the fuel cell from an external power source, with the positive electrode and the negative electrode of the external power source connected to the anode and the cathode of the fuel cell, respectively, while supplying an organic fuel and an inert gas to the anode and the cathode, respectively.

Method for activating fuel cell

The direct oxidation fuel cell of the present invention is provided with: a membrane electrode assembly including an anode, a cathode, and an electrolyte membrane interposed between the anode and the cathode; an anode-side separator having a fuel flow channel for supplying fuel to the anode; and a cathode-side separator having an oxidant flow channel for supplying oxidant to the cathode, in which the anode includes an anode catalyst layer disposed at the side of the electrolyte membrane and an anode diffusion layer disposed at the side of the anode-side separator. The anode diffusion layer includes a water repellent layer disposed at the side of the anode catalyst layer and including a first conductive agent and a first water repellent agent; and a substrate layer disposed at the side of the anode-side separator, and the porosity of the substrate layer is higher at the downstream side than at the upstream side of the fuel flow.

Direct oxidation fuel cell

A fuel cell system includes a fuel cell stack for generating power and power generation control means. The fuel cell stack has at least one cell that includes a cathode to which an oxidant is supplied, an anode to which a fuel is supplied, and a polymer electrolyte membrane sandwiched between the cathode and the anode. The power generation control means has dryness degree determination means for determining the degree of dryness of the fuel cell stack based on shut-down period. When the shut-down period is shorter than a predetermined period of time, the power generation control means supplies a gas for drying to the cathode for a predetermined period of time, to remove water remaining in the cathode. When the shut-down period is equal to or longer than the predetermined period of time, such a drying operation is not performed.

Fuel cell system

A direct oxidation fuel cell of the invention includes at least one unit cell, the unit cell including a membrane-electrode assembly including an electrolyte membrane and an anode and a cathode sandwiching the electrolyte membrane, an anode-side separator being in contact with the anode, and a cathode-side separator being in contact with the cathode. The anode includes an anode catalyst layer and an anode diffusion layer, the anode catalyst layer containing an anode catalyst. The cathode includes a cathode catalyst layer and a cathode diffusion layer, the cathode catalyst layer containing a cathode catalyst. The anode-side separator has a fuel flow channel for supplying fuel to the anode. A portion of the cathode catalyst layer facing the upstream of the fuel flow channel has an effective reaction area per unit area larger than that of a portion of the cathode catalyst layer facing the downstream of the fuel flow channel.

The direct oxidation fuel cell of the invention includes at least one unit cell, the unit cell including: a membrane-electrode assembly including an anode, a cathode, and an electrolyte membrane interposed therebetween; an anode-side separator; and a cathode-side separator. The cathode includes a first cathode catalyst layer, a diffusion layer being in contact with the cathode-side separator, and an intermediate layer disposed therebetween. The intermediate layer includes a second cathode catalyst layer and a porous composite layer, the porous composite layer containing a hydrophobic material and an electron-conductive material. The anode-side separator has a fuel flow channel, and the cathode-side separator has an oxidant flow channel. At least a portion of the intermediate layer facing the upstream portion of the fuel flow channel includes the second cathode catalyst layer, and at least portions of the intermediate layer facing the midstream and downstream portions of the fuel flow channel include the porous composite layer.

A direct oxidation fuel cell of this invention has at least one unit cell including: a membrane-electrode assembly comprising an electrolyte membrane sandwiched between an anode and a cathode, each of the anode and the cathode including a catalyst layer and a diffusion layer; an anode-side separator with a fuel flow channel for supplying a fuel to the anode; and a cathode-side separator with an oxidant flow channel for supplying an oxidant containing oxygen gas to the cathode. The fuel flow channel and the oxidant flow channel are so structured that the concentration of the oxygen gas in the oxidant flow channel is higher at a part opposing an upstream part of the fuel flow channel than at a part opposing a downstream part of the fuel flow channel.

A method for operating a fuel cell system including a fuel cell stack composed of a plurality of cells connected in series. The method includes the steps of: (a) supplying a fuel and an oxidant to anodes and cathodes of the cells, respectively, depending on a load to generate power at a constant voltage under constant voltage control; (b) temporarily suspending the supply of the oxidant with the fuel being supplied; and (c) lowering the constant voltage to a predetermined voltage simultaneously with or immediately before the suspension of the supply of the oxidant. According to this operation method, when the supply of the oxidant is suspended, a platinum catalyst in the cathodes can be reduced and reactivated in all the cells.

Method for operating fuel cell system

A direct oxidation fuel cell of this invention has at least one unit cell including: a membrane-electrode assembly including an electrolyte membrane sandwiched between an anode and a cathode, each of the anode and the cathode including a catalyst layer and a diffusion layer; an anode-side separator with a fuel flow channel for supplying a fuel to the anode; and a cathode-side separator with an oxidant flow channel for supplying an oxidant to the cathode. The catalyst layer of at least one of the anode and the cathode includes high-porosity regions and low-porosity regions, and the high-porosity regions and the low-porosity regions are arranged in a mixed configuration.

A fuel cell system includes a fuel cell including at least one unit cell having an anode, an anode-side flow channel for supplying a fuel to the anode, a cathode, and a cathode-side flow channel for supplying an oxidant to the cathode. The fuel cell system further includes a gas-liquid separator for catalytically purifying the effluent from the anode and the effluent from the cathode to collect liquid. The gas-liquid separator is connected to an anode-side discharge path for the effluent and a cathode-side discharge path for the effluent, which are in fluid communication with a fuel outlet of the anode-side flow channel and an oxidant outlet of the cathode-side flow channel, respectively.

An anode electrode for use in a fuel cell comprises a stacked structure including, in sequence: a catalyst layer, a hydrophobic, microporous layer ('MPL'), a porous gas diffusion layer ('GDL'), and an anode plate with at least one recessed fuel supply-fuel/gas exhaust channel formed in a surface thereof facing the GDL, wherein the stacked structure further comprises at least one hydrophobic region aligned with the at least one recessed channel. The electrode is useful in direct oxidation fuel cells and systems, such as direct methanol fuel cells operating with highly concentrated liquid fuel.

Anode electrodes for direct oxidation fuel cells and systems operating with concentrated liquid fuel

A direct methanol fuel cell of the present invention includes a unit cell having an electrolyte membrane, an anode on one surface of the electrolyte membrane, and a cathode on the other surface of the electrolyte membrane. The anode includes an anode catalyst layer and an anode diffusion layer. The anode catalyst layer is in contact with a surface of the electrolyte membrane. The anode diffusion layer is in contact with a surface of the anode catalyst layer opposite to the surface of the anode catalyst layer in contact with the electrolyte membrane. A methanol flux value Jof the anode diffusion layer and a methanol flux value Jof the electrolyte membrane satisfy the following relations:=1&#xd7;10to 5&#xd7;10mol/(cm&#xb7;min.),&#x2003;&#x2003;(i)and&#x2266;1&#xd7;10[mol/(cm&#xb7;min.)].&#x2003;&#x2003;(ii)

Direct methanol fuel cell

The fuel cell of this invention includes at least one unit cell that includes: a membrane-electrode assembly including an electrolyte membrane sandwiched between an anode and a cathode; an anode-side separator in contact with the anode and having a fuel flow path for supplying a fuel to the anode; and a cathode-side separator in contact with the cathode and having an oxidant flow path for supplying an oxidant to the cathode. The fuel flow path has a first flow channel and a second flow channel, and each of the first flow channel and the second flow channel has a fuel inlet and a fuel outlet. The first flow channel and the second flow channel are adjacent to each other, and the direction of the flow of fuel through the first flow channel is opposite to the direction of the flow of fuel through the second flow channel.

Fuel cell

To prevent the flooding phenomenon at the cathode in a unit cell where the temperature is relatively low or the supply of air is small, a fuel cell stack includes at least three flat unit cells stacked with separators interposed therebetween, the unit cells comprising an anode, a cathode and an electrolyte membrane sandwiched therebetween, and having an oxidant channel formed on the surface of the separator adjacent to the cathode, and the anode and the cathode comprising a catalyst layer attached to the electrolyte membrane and a diffusion layer, wherein the cross-sectional area of the inlet side of the oxidant channel, the area of the cathode catalyst layer, the thickness of the electrolyte membrane or the amount of a water repellent contained in the combination of the cathode and the oxidant channel is the largest in at least one of the unit cells at the ends of the stack.

Growing community of inventors

Osaka, Japan

Hideyuki Ueda