Bipolar alkaline water electrolysis unit and electrolytic cell

Patent metadata

Field	Value
Publication number	US-9683300-B2
Application number	US-201314408834-A
Country	US
Kind code	B2
Filing date	Jun 17, 2013
Priority date	Jun 18, 2012
Publication date	Jun 20, 2017
Grant date	Jun 20, 2017

Abstract

A bipolar alkaline water electrolysis unit incorporated in an electrolytic cell for electrolyzing an electrolytic solution of alkaline water to obtain oxygen and hydrogen, the bipolar alkaline water electrolysis unit including an oxygen generating anode, a hydrogen generating cathode, a conductive partition wall that separates the anode and the cathode from each other, and an outer frame that surrounds the conductive partition wall, wherein a gas and electrolytic solution passage is provided at an upper portion of the conductive partition wall and/or the outer frame, and an electrolytic solution passage is provided at a lower part of the conductive partition wall and/or the outer frame.

First claim

The invention claimed is:

1. A bipolar alkaline water electrolysis unit comprising:
an anode comprising a conductive base material and a catalytic layer disposed on the conductive base material,
wherein the catalytic layer comprises a metal crystal of nickel, and has pores,
of the pores in the catalytic layer,
a first pore with a pore size of 2 to 5 nm has a specific surface area of 0.6 to 2.0 m 2 /g,
the first pore has a pore volume of 3×10 −4 to 9×10 −4 ml/g,
of the pores, a second pore with a pore size of 0.01 to 2.00 μm has a specific surface area of 2.0 to 5.0 m 2 /g, and
the second pore has a pore volume of 0.04 to 0.2 ml/g.

2. The bipolar alkaline water electrolysis unit according to claim 1 , wherein when an X ray diffracted by a (1 1 1) face of the metal crystal of the nickel in the catalytic layer has a peak intensity INi and an X ray diffracted by a (0 1 2) face of NiO in the catalytic layer has a peak intensity INiO, a value of [INi/(INi+INiO)]×100 is 75 to 100%.

3. The bipolar alkaline water electrolysis unit according to claim 1 , wherein a thickness of the catalytic layer is 50 to 800 μm.

4. The bipolar alkaline water electrolysis unit according to claim 1 , wherein the catalytic layer is formed by:
a first step of spraying nickel oxide onto a conductive base material by a spraying method; and
a second step of reducing the nickel oxide sprayed on the conductive base material.

5. The bipolar alkaline water electrolysis unit according to claim 4 , wherein, in the second step, the catalytic layer is formed by reducing the nickel oxide sprayed on the conductive base material by means water electrolysis using the nickel oxide sprayed on the conductive base materials as a cathode.

6. The bipolar alkaline water electrolysis unit according to claim 4 , wherein, in the second step, catalytic layer is formed by reducing the nickel oxide sprayed on the conductive base material using hydrogen.

7. The bipolar alkaline water electrolysis unit according to claim 4 , wherein, in the second step, the catalytic layer is formed by reducing the nickel oxide sprayed on the conductive base material, at 180 to 250° C. using hydrogen.

8. The bipolar alkaline water electrolysis unit according to claim 4 , wherein the catalytic layer is formed through a step of granulating the nickel oxide before the first step, and
a particle size of powder of the nickel oxide is 1.0 to 5.0 μm before granulation.

9. A bipolar alkaline water electrolysis unit comprising in an electrolytic cell in which an electrolytic solution of alkaline water is electrolyzed to obtain oxygen and hydrogen,
the bipolar alkaline water electrolysis unit comprising:
an anode comprising an oxygen generating porous medium;
a hydrogen generating cathode;
a conductive partition wall that separates the anode and the cathode from each other;
an outer frame that surrounds the conductive partition wall,
a gas and electrolytic solution passage provided between an upper portion of both the anode and the cathode and an upper portion of the outer frame, and
an electrolytic solution passage provided between a lower portion of both the anode and the cathode and a lower portion of the outer frame,
wherein the gas and electrolytic solution passage and the electrolytic solution passage extend along a direction that is substantially orthogonal to the conductive partition wall,
wherein either (i) the anode or cathode is supported by the conductive partition wall via a conductive elastic medium or (ii) the anode or the cathode is supported by the conductive partition wall via a conductive support medium, and
wherein the anode comprises a conductive base material and a catalytic layer disposed on the conductive base material,
wherein the catalytic layer comprises a metal crystal of nickel, and has pores,
of the pores in the catalytic layer,
a first pore with a pore size of 2 to 5 nm has a specific surface area of 0.6 to 2.0 m 2 /g,
the first pore has a pore volume of 3×10 −4 to 9×10 −4 ml/g,
of the pores, a second pore with a pore size of 0.01 to 2.00 (μm has a specific surface area of 2.0 to 5.0 m 2 /g, and
the second pore has a pore volume of 0.04 to 0.2 ml/g.

10. The bipolar alkaline water electrolysis unit according to claim 9 , comprising a thin metal plate part extending from the conductive partition wall and covering at least a part of the outer frame, wherein
the outer frame is fixed to the thin metal plate part to provide an integral structure.

11. The bipolar alkaline water electrolysis unit according to claim 10 , wherein the thin metal plate part comprises an anode side flange pan overlapping the outer frame on the anode side and a cathode side flange pan overlapping the outer frame on the cathode side,
the outer frame is sandwiched between a flange portion of the anode side flange pan and a flange portion of the cathode side flange pan, and
a distance from an anode side reference surface including an anode side surface of the conductive partition wall to a flange surface of the anode side flange pan and a distance from a cathode side reference surface including a cathode side surface of the conductive partition wall to a flange surface of the cathode side flange pan are each 5 mm or more and 40 mm or less.

12. The bipolar alkaline water electrolysis unit according to claim 9 , wherein a part or all of the outer frame is resin, and an outer frame is provided which surrounds the conductive partition wall and holds the conductive partition wall in a sandwiching manner.

13. The bipolar alkaline water electrolysis unit according to claim 9 , wherein a distance from an anode side surface of the outer frame to an anode side surface of the partition wall and a distance from a cathode side surface of the outer frame to a cathode side surface of the partition wall are each 5 mm or more and 40 mm or less.

14. The bipolar alkaline water electrolysis unit according to claim 9 , wherein the outer frame is divided into an anode side frame part disposed on the anode side of the conductive partition wall and a cathode side frame part disposed on the cathode side of the conductive partition wall, and
a part of the conductive partition wall is sandwiched between the anode side frame part and the cathode side frame part.

15. The bipolar alkaline water electrolysis unit according to claim 14 , wherein a thickness of the anode side frame part and a thickness of the cathode side frame part are each 5 mm or more and 40 mm or less.

16. The bipolar alkaline water electrolysis unit according to claim 9 , wherein the conductive elastic medium is a spring.

17. The bipolar alkaline water electrolysis unit according to claim 16 , wherein a rib for fixing the anode, the cathode, or the spring is attached to the conductive partition wall.

18. The bipolar alkaline water electrolysis unit according to claim 9 , wherein the conductive elastic medium comprises a current collector and a cushion mat layer, and the cathode or the anode contacts with the cushion mat layer.

19. The bipolar alkaline water electrolysis unit according to claim 18 , wherein a rib for fixing the anode, the cathode, or the current collector is attached to conductive partition wall.

20. The bipolar alkaline water electrolysis unit according to claim 18 , wherein at least one of a surface of the partition wall, a surface of a part of the conductive elastic medium, or a surface of one of surfaces of the current collector is coated with a selected one of Raney nickel, porous nickel, and porous nic

Assignees

• Asahi Chemical Ind

Inventors

• Noaki Yasuhide
• UCHINO Yousuke
• Miyoshi Keiji

Classifications

• C25B11/0447

  Chemistry & Metallurgy · mapped topic

• C25B11/035 Primary

  Chemistry & Metallurgy · mapped topic

• Y02E60/366

  Cross-Sectional Technologies · mapped topic

• C25B9/20

  Chemistry & Metallurgy · mapped topic

• C25B1/10

  Chemistry & Metallurgy · mapped topic