Fuel cell and fuel cell system

• US 20020106541A1
• Filed: 10/31/2001
• Published: 08/08/2002
• Est. Priority Date: 11/07/2000
• Status: Active Grant

• Current Assignee: Sony Corporation (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Yamada, Atsuo, Ata, Masafumi
• Granted Patent: US 6,805,985 B2
• Time in Patent Office: Days
• US Class Current: 429/21
• CPC Class Codes: B82Y 30/00 Nanotechnology for materials or surface science, e.g. nanocomposites
• CPC Class Codes: C01B 2203/041 In-situ membrane purification during hydrogen production
• CPC Class Codes: C01B 2203/0465 Composition of the impurity
• CPC Class Codes: C01B 3/0021 Carbon, e.g. active carbon, carbon nanotubes, fullerenes; Treatment thereof
• CPC Class Codes: C01B 3/501 by diffusion
• CPC Class Codes: H01M 4/8605 Porous electrodes
• CPC Class Codes: H01M 8/04216 characterised by the choice for a specific material, e.g. carbon, hydride, absorbent
• CPC Class Codes: H01M 8/0656 by electrochemical means H01M8/065 takes precedence
• CPC Class Codes: H01M 8/0662 Treatment of gaseous reactants or gaseous residues, e.g. cleaning
• CPC Class Codes: H01M 8/1004 characterised by membrane-electrode assemblies [MEA] H01M8/12 takes precedence
• CPC Class Codes: H01M 8/186 by electrolytic decomposition of the electrolytic solution or the formed water product
• CPC Class Codes: Y02E 60/32 Hydrogen storage
• CPC Class Codes: Y02E 60/36 Hydrogen production from non-carbon containing sources, e.g. by water electrolysis
• CPC Class Codes: Y02E 60/50 Fuel cells

Abstract

A fuel cell usable as a small-sized secondary cell such as a button type cell and a fuel cell system including the fuel cells are provided. The fuel cell has a first electrode, an electrolyte membrane, a second electrode, and a hydrogen storing material. The electrolyte membrane has polyfullerene hydroxide as a proton conductor. When a negative voltage is applied to the first electrode and a positive electrode is applied to the second electrode, protons, electrons, and oxygen are generated from water at the second electrode, and hydrogen is generated from the electrons and the protons at the first electrode. The hydrogen thus generated is stored in the hydrogen storing material, thus performing so-called charging. At the time of power generation, protons and electrons are generated, at the first electrode, from hydrogen supplied from the hydrogen storing material, and the generated protons are conducted to the second electrode via the electrolyte membrane and water is generated at the second electrode.

Claims

1. A fuel cell comprising:

a first electrode having a catalyst for generating hydrogen;

a second electrode having a catalyst for generating oxygen, said second electrode being provided while allowed to be in contact with water; and

a proton conductive electrolyte membrane having a proton conductor produced by introducing proton dissociative groups into a base body composed of a carbonaceous material containing carbon as a main component, said electrolyte membrane being provided between said first electrode and second electrode;

wherein when a negative voltage is applied to said first electrode and a positive voltage is applied to said second electrode, oxygen, protons and electrons are generated from water under the presence of said catalyst at said second electrode, and hydrogen is generated from the protons and the electrons under the presence of said catalyst at said first electrode.

2. A fuel cell according to claim 1, further comprising a storing material for capturing and storing the hydrogen generated at said first electrode.

3. A fuel cell according to claim 2, wherein said first electrode functions, in a state that no voltage is applied to said first electrode, as a fuel electrode which comes in contact with the hydrogen stored in said storing material, to generate protons and electrons from the hydrogen under the presence of said catalyst at said first electrode;

said electrolyte membrane functions, in a state that no voltage is not applied to each of said first electrode and second electrode, as an ion exchange membrane which conducts the protons generated at said first electrode to said second electrode; and

said second electrode functions, in a state that no voltage is applied to said second electrode, as an oxygen electrode which comes in contact oxygen, to generate water from the oxygen, the electrons, and the protons under the presence of said catalyst at said second electrode;

whereby said fuel cell releases electric power as a whole, to thus perform power generation.

4. A fuel cell according to claim 2, wherein said storing material is made from fullerene molecules, carbon nanotubes, or carbon nanofibers.

5. A fuel cell according to claim 2, wherein said storing material is made from a hydrogen storing alloy.

6. A fuel cell according to claim 5, wherein a separation membrane for preventing said storing material from being corroded is provided between said storing material and said first electrode.

7. A fuel cell according to claim 6, wherein said separation membrane is a hydrogen selectively permeable membrane.

8. A fuel cell according to claim 6, wherein said separation membrane is made from polyethylene, polypropylene, or polytetrafluoroethylene.

9. A fuel cell according to claim 2, wherein said storing material is in the form of fine particles which are aggregated into a storing body, and said storing body is disposed in proximity to said first electrode or directly connected to said first electrode

10. A fuel cell according to claim 9, wherein a separation membrane for preventing said fine particles of said storing material from being scattered to said first electrode is provided between said storing material and said first electrode.

11. A fuel cell according to claim 10, wherein said separation membrane is a hydrogen selectively permeable membrane.

12. A fuel cell according to claim 10, wherein said separation membrane is made from polyethylene, polypropylene, or polytetrafluoroethylene.

14. A fuel cell system according to claim 13, wherein each of said membrane-electrode assemblies has a storing material for capturing and storing the generated hydrogen and supplying the hydrogen to said fuel electrode.

15. A fuel cell system according to claim 13, wherein at least one of said membrane-electrode assemblies acts as a gas supply source for generating hydrogen, and at least one of the rest of said membrane-electrode assemblies acts as a power generator communicated to said gas supply source.

13. A fuel cell system having a plurality of membrane-electrode assemblies, each of said membrane-electrode assemblies comprising:

a first electrode having a catalyst for generating hydrogen;

a second electrode having a catalyst for generating oxygen, said second electrode being provided while allowed to be in contact with water; and

a proton conductive electrolyte membrane having a proton conductor produced by introducing proton dissociative groups into a base body composed of a carbonaceous material containing carbon as a main component, said electrolyte membrane being provided between said first electrode and second electrode;

wherein when a negative voltage is applied to said first electrode and a positive voltage is applied to said second electrode, oxygen, protons and electrons are generated from water under the presence of said catalyst at said second electrode, and hydrogen is generated from the protons and the electrons under the presence of said catalyst at said first electrode; and

wherein said first electrode functions, in a state that no voltage is applied to said first electrode, as a fuel electrode which comes in contact with the hydrogen, to generate protons and electrons from the hydrogen under the presence of said catalyst at said first electrode;

said electrolyte membrane functions, in a state that no voltage is not applied to each of said first electrode and second electrode, as an ion exchange membrane which conducts the protons generated at said first electrode to said second electrode; and

said second electrode functions, in a state that no voltage is applied to said second electrode, as an oxygen electrode which comes in contact oxygen, to generate water from the oxygen, the electrons, and the protons under the presence of said catalyst at said second electrode;

whereby said membrane-electrode assembly constitutes a fuel cell as a whole, to releases electric power, thus performing power generation.