JPWO2018139597A1 - Electrolytic cell, electrolytic device, electrolytic method - Google Patents

Abstract

A plurality of bipolar elements including an anode, a cathode, a partition separating the anode and the cathode, and an outer frame bordering the partition are superimposed with the diaphragm interposed therebetween, and the partition and the outer are provided outside the outer frame. A bipolar electrolyzer comprising a header in communication with an electrode chamber defined by a frame and a diaphragm, wherein the electrical capacity of the anode is in the range of 4825 C / m 2 to 965000 C / m 2 and the electrical capacity of the cathode is 4825 C / It is the range of m2-965000 C / m <2>, The bipolar battery, an electrolytic device, the water electrolysis method characterized by the above-mentioned.

Description

  The present invention relates to a bipolar electrolyzer, an electrolyzer, and a water electrolysis method.

  In recent years, in order to solve problems such as global warming due to greenhouse gases such as carbon dioxide and reduction of reserves of fossil fuels, technologies such as wind power generation and solar power generation using renewable energy are attracting attention.

  Renewable energy has the property that its fluctuation is very large because its output depends on the climatic conditions. Therefore, it is not always possible to transport the power obtained by renewable energy generation to the general power system, and there are concerns about social impacts such as imbalance of power supply and demand and instability of the power system. There is.

  Therefore, research has been conducted to use power generated from renewable energy instead of a form that can be stored and transported. Specifically, it is considered to generate hydrogen that can be stored and transported by electrolysis (electrolysis) of water using electric power generated from renewable energy, and to use hydrogen as an energy source or raw material. There is.

  Hydrogen is widely used industrially in the fields of petroleum refining, chemical synthesis, metal refining, etc., and in recent years, it can be used in hydrogen stations for fuel cell vehicles (FCVs), smart communities, hydrogen power plants etc. Sex is also spreading. For this reason, there is high hope for the development of technology to obtain particularly high purity hydrogen from renewable energy.

  As a method of water electrolysis, there are a solid polymer type water electrolysis method, a high temperature steam electrolysis method, an alkaline water electrolysis method and the like. Among them, alkaline water electrolysis is one of particularly strong ones because it has been industrialized for several decades or more, can be carried out on a large scale, and is inexpensive compared to other water electrolysis devices. It is done.

  However, in order to apply alkaline water electrolysis as a means for storing and transporting energy in the future, it is possible to carry out water electrolysis using power efficiently and stably, as described above. There is a need to. Therefore, it is required to solve various problems of the electrolysis cell and apparatus for alkaline water electrolysis etc.

  In order to solve the problem of reducing the electrolysis voltage in alkaline water electrolysis and improving the power consumption per unit of hydrogen production, the structure of the electrolysis cell, in particular, a structure in which the gap between the diaphragm and the electrode is substantially eliminated. It is well known that it is effective to adopt a structure called a zero gap structure (see Patent Documents 1 and 2). In the zero gap structure, the generated gas is quickly released to the side opposite to the diaphragm side of the electrode through the pores of the electrode, thereby reducing the distance between the electrodes and minimizing the generation of the gas pool near the electrodes to achieve electrolysis. The voltage is suppressed low. The zero gap structure is extremely effective in suppressing the electrolysis voltage, and is employed in various electrolysis devices.

  On the other hand, it is also reported by Detlef Stolten et al. That the optimal selection of electrodes and diaphragms, optimization of the structure of the electrolytic cell, etc. are important in order to realize efficient and stable alkaline water electrolysis. Non-Patent Document 1). Further, in recent years, research on addressing the above-mentioned various problems has been actively carried out for an alkaline water electrolysis electrolytic cell having a zero gap structure (see Patent Documents 3 and 4).

U.S. Pat. No. 4,530,743 JP-A-59-173281 International Publication No. 2013/191140 International Publication No. 2014/178317

Detlef Stolten, "Hydrogen Energy", Wiley-VCH Verlag GmbH & Co., Germany. KGaA, 2010, pages 254 to 257

  However, although various structures have been developed as bipolar electrolytic cells so far, stable operation is possible when supplying fluctuating power such as renewable energy to such electrolytic cells. Requires control of a complex electric drive control system, but an improvement is required because the electric drive control system can not be controlled when a sudden power supply stop occurs.

  Therefore, an object of the present invention is to enable hydrogen production with high efficiency at the time of operation with a fluctuating power source such as renewable energy, and to enable stabilization of the electric control system at the time of power supply interruption. .

The gist of the present invention is as follows.
In the bipolar electrolytic cell according to the present invention, a plurality of bipolar elements each including an anode, a cathode, a partition separating the anode and the cathode, and an outer frame bordering the partition sandwich a diaphragm with a diaphragm interposed therebetween It is a bipolar electrolysis cell provided with the header which is united and is connected with the electrode room defined by the partition, the outer frame, and the diaphragm outside the outer frame,
The electric capacity of the anode is in the range of 4825 C / m ^{2 to} 965000 C / m ² , and the electric capacity of the cathode is in the range of 4825 C / m ^{2 to} 965000 C / m ² .
It is characterized by
Here, the bipolar electrolyzer of the present invention is preferably a bipolar electrolyzer for alkaline water electrolysis.
In the bipolar electrolyzer of the present invention, when the area of the current-carrying surface of the bipolar element is S1, the cross-sectional area of the flow path of the header is S2, and the length of the flow path of the header is L2. It is preferable that (S2 / S1) / L2 be in the range of 1.5 × 10 ⁻⁶ m ^{−1 to} 2.3 × 10 ⁻⁴ m ⁻¹ .
Furthermore, in the bipolar electrolytic cell of the present invention, it is preferable that the smaller one of the electric capacity of the anode and the electric capacity of the cathode is in the range of 9650 C / m ^{2 to} 955350 C / m ² .
Furthermore, in the bipolar electrolytic cell of the present invention, the electric capacity of the anode is preferably larger than the electric capacity of the cathode.
Furthermore, in the bipolar electrolytic cell of the present invention, the electric capacity of the cathode is preferably more than 0.1 times and not more than 0.99 times the electric capacity of the anode.
Further, in the bipolar electrolytic cell of the present invention, the electric capacity of the cathode is preferably more than 0.1 times and 0.49 times or less of the electric capacity of the anode.
Furthermore, the bipolar type electrolytic cell of the present invention, the actual electrode surface area of the geometric cell area 1 m ² per the ^anode, is preferably in the range of 90m ² ~10000m 2.
Furthermore, the bipolar electrolyzer of the present invention preferably has 50 to 500 bipolar elements.
Furthermore, the bipolar type electrolytic cell of the present invention, it is preferable that the S1 is a 0.1 m ² through 10m ^2.
Furthermore, in the bipolar electrolytic cell of the present invention, the thickness d of the electrolytic cell is preferably 10 mm to 100 mm.
Furthermore, in the bipolar electrolytic cell of the present invention, preferably, the anode contains at least one nickel compound selected from the group consisting of nickel oxide, metallic nickel, nickel hydroxide and a nickel alloy.
Furthermore, in the bipolar electrolyzer of the present invention, the anode includes a conductive substrate, and a catalyst layer disposed on the conductive substrate, and the catalyst layer includes a metal crystal of nickel, And the specific surface area of the 1st pore which has a pore and whose pore diameter is in the range of 2 to 5 nm among the pores of the catalyst layer is 0.6 to 2.0 m ² / g, Among the above-mentioned pores, the pore volume of one pore is 3 × 10 ^{−4 to} 9 × 10 ⁻⁴ ml / g, and the pore diameter is in the range of 0.01 to 2.00 μm. The specific surface area is 2.0 to 5.0 m ² / g, the pore volume of the second pore is 0.04 to 0.2 ml / g, and the thickness of the catalyst layer is 50 to 800 μm Is preferred.
Furthermore, in the bipolar electrolyzer according to the present invention, the cathode is made of Ru-La-Pt, Ru-Ce, Pt-Ce, Pt-Ir, Ir-Pt-Pd, Pt-Ni. It is preferable to include at least one Pt group compound selected from the group consisting of
Further, in the bipolar electrolytic cell of the present invention, the constitution of the cathode and the anode has a catalyst layer on the surface of the conductive substrate, and the conductive substrate is metal nickel, nickel oxide, hydroxide hydroxide It is preferable to include at least one nickel compound selected from the group consisting of nickel and nickel alloys.
Furthermore, in the bipolar electrolytic cell of the present invention, the cathode and the anode preferably have a mesh-like structure.
Furthermore, in the bipolar electrolytic cell of the present invention, the base material of the cathode preferably has a wire diameter in the range of 0.05 mm to 0.5 mm, and the opening preferably has a range of 30 mesh to 80 mesh. .
Furthermore, it is preferable that the base material of the said anode is a mesh-like structure which has an aperture ratio in the range of 20%-60% of the bipolar electrolysis cell of this invention.
Further, in the bipolar electrolytic cell of the present invention, it is preferable that the electrolytic cells be electrically connected in series.
Furthermore, the bipolar electrolytic cell according to the present invention comprises a bipolar element having the cathode, the anode, the diaphragm, and a partition that defines the anode chamber and the cathode chamber, and the diaphragm is positioned between the cathode and the anode. Preferably, the diaphragm is in contact with the cathode and the anode.

The electrolytic device of the present invention comprises the bipolar electrolytic cell of the present invention, an electrolytic solution circulation pump for circulating the electrolytic solution, a gas-liquid separation tank for separating the electrolytic solution and hydrogen and / or oxygen, and water. And a water charging pump for supplying water.
In addition, the electrolytic device of the present invention may further include a detector that detects the stop of the power supply when the power supply to the electrolytic device of the present invention is stopped, and a controller that automatically stops the electrolyte circulation pump. preferable.

  The water electrolysis method of the present invention is characterized in that the electrolyte circulation pump is stopped when the power supply to the electrolytic device of the present invention is stopped.

The method for producing hydrogen according to the present invention is a method for producing hydrogen, wherein water containing alkali is electrolyzed by an electrolytic cell to produce hydrogen, wherein the electrolytic cell isolates an anode, a cathode, the anode and the cathode. A plurality of bipolar elements each including a partition wall and an outer frame bordering the partition wall are overlapped with a diaphragm interposed therebetween, and are defined by the partition wall, the outer frame, and the diaphragm outside the outer frame. And a header in communication with the electrode chamber, wherein the electric capacity of the anode is in the range of 4825 C / m ^{2 to} 965000 C / m ² , and the electric capacity of the cathode is 4825 C / m ^{2 to} 965000 C. It is characterized by being in the range of / m ² .

  According to the present invention, it is possible to produce hydrogen with high efficiency at the time of operation with a fluctuating power source such as renewable energy, and to stabilize the electric control system at the time of stopping the power supply.

BRIEF DESCRIPTION OF THE DRAWINGS It is a side view shown about the whole of an example of the bipolar | dipolar type electrolytic vessel for alkaline water electrolysis of this embodiment. It is a perspective view shown about the electrolysis chamber of an example of the bipolar type electrolytic cell for alkaline water electrolysis of this embodiment, a header, and a channel. It is a perspective view which shows the flow of the electrolyte solution in an example of the bipolar | dipolar type electrolytic vessel for alkaline water electrolysis of this embodiment. It is a top view which shows the example of the bipolar | dipolar type electrolytic vessel for alkaline water electrolysis of the external header type of this embodiment. It is a figure showing an outline of an electrolysis device for alkaline water electrolysis of this embodiment.

  Hereinafter, modes for carrying out the present invention (hereinafter, referred to as “the present embodiment”) will be described in detail. The present invention is not limited to the following embodiments, and can be variously modified and implemented within the scope of the invention.

The side view about the whole of an example of the bipolar | dipolar type electrolytic cell for alkaline water electrolysis of this embodiment is shown in FIG.
In FIG. 2, the perspective view about the electrolysis chamber of an example of the bipolar type electrolytic cell for alkaline water electrolysis of this embodiment, a header, and a conduit | pipe is shown.
In FIG. 3, the perspective view about the flow of the electrolyte solution in an example of the bipolar type electrolytic cell for alkaline water electrolysis of this embodiment is shown.
As shown in FIG. 1, a bipolar electrolytic cell 50 for alkaline water electrolysis according to this embodiment includes an anode 2a, a cathode 2c, a partition 1 for separating the anode 2a and the cathode 2c, and an outer frame for bordering the partition 1 And a plurality of bipolar electrodes 60 each including the first and second electrodes 3 and 4 are stacked with the diaphragm 4 interposed therebetween.

(Bipolar electrolysis cell)
The bipolar type is one of the methods of connecting a large number of cells to a power supply, and a plurality of bipolar type elements 60 each having an anode 2a on one side and a cathode 2c on one side are arranged in the same direction and connected in series. Is connected to the power supply.
The bipolar electrolyzer 50 is characterized in that the current of the power supply can be reduced, and a large amount of compounds, predetermined substances, etc. can be produced in a short time by electrolysis. In the power supply equipment, if the output is the same, the constant current and the high voltage become cheaper and more compact, so from the industrial point of view, the bipolar type is preferable to the single pole type.

((Bipolar element))
As shown in FIG. 1, the bipolar element 60 used in the bipolar electrode type electrolytic cell 50 for alkaline water electrolysis in one example has a partition 1 for separating the anode 2a and the cathode 2c, and an outer frame for bordering the partition 1 It has three. More specifically, the partition 1 has conductivity, and the outer frame 3 is provided along the outer edge of the partition 1 so as to surround the partition 1.

  In the present embodiment, the bipolar element 60 may be used so that the given direction D1 along the partition wall 1 is usually the vertical direction, specifically, in FIGS. 2 and 3, As shown, when the plan view shape of the partition wall 1 is rectangular, it is used such that a given direction D1 along the partition wall 1 is the same as the direction of one of the two pairs of sides facing each other. (See FIGS. 1 to 5). And in this specification, the above-mentioned perpendicular direction is also called an electrolysis solution passage direction.

In the present embodiment, as shown in FIG. 1, the bipolar electrolyzer 50 is configured by laminating the required number of bipolar elements 60.
In the example shown in FIG. 1, in the bipolar electrolytic cell 50, the fast head 51g, the insulating plate 51i and the anode terminal element 51a are arranged in order from one end, and further, the anode side gasket portion 7, the diaphragm 4 and the cathode side gasket portion 7 and the bipolar elements 60 are arranged in this order. At this time, the bipolar element 60 is disposed so as to direct the cathode 2 c to the anode terminal element 51 a side. The anode side gasket portion 7 to the bipolar element 60 are repeatedly arranged by the number required for the design production amount. After arranging from the anode side gasket part 7 to the bipolar element 60 repeatedly as many times as necessary, again, the anode side gasket part 7, the diaphragm 4 and the cathode side gasket part 7 are arranged side by side, and finally the cathode terminal element 51c, insulation The plate 51i and the loose head 51g are arranged in this order. The bipolar electrolyzer 50 is integrated by tightening the whole with a fastening mechanism such as a tie rod system 51r (see FIG. 1) or a hydraulic cylinder system to form the bipolar electrolyzer 50.
The arrangement of the bipolar electrolytic cell 50 can be arbitrarily selected from the anode 2 a side or the cathode 2 c side, and is not limited to the above-described order.

  As shown in FIG. 1, in the bipolar electrolyzer 50, the bipolar element 60 is disposed between the anode terminal element 51a and the cathode terminal element 51c. The diaphragm 4 is disposed between the anode terminal element 51a and the bipolar element 60, between the adjacently arranged bipolar elements 60, and between the bipolar element 60 and the cathode terminal element 51c. .

  Further, in the bipolar electrolytic cell 50 in the present embodiment, as shown in FIGS. 2 and 3, the partition 1, the outer frame 3, and the diaphragm 4 define an electrode chamber 5 through which the electrolytic solution passes.

  In the present embodiment, in particular, a portion of the bipolar electrolyzer 50 between the adjacent partitions 1 between the two bipolar elements 60 and between the adjacent bipolar element 60 and the terminal element. A portion between the partition walls 1 is referred to as an electrolysis cell 65. The electrolysis cell 65 includes the partition 1 of one element, the anode chamber 5a, the anode 2a, the diaphragm 4 and the cathode 2c of the other element, the cathode chamber 5c, and the partition 1.

  Specifically, the electrode chamber 5 has an electrolyte inlet 5 i for introducing an electrolyte into the electrode chamber 5 and an electrolyte outlet 5 o for discharging the electrolyte from the electrode chamber 5 at the boundary with the outer frame 3. More specifically, the anode chamber 5a is provided with an anode electrolyte inlet 5ai for introducing the electrolyte into the anode chamber 5a, and an anode electrolyte outlet 5ao for extracting the electrolyte discharged from the anode chamber 5a. Similarly, the cathode chamber 5c is provided with a cathode electrolyte solution inlet 5ci for introducing the electrolyte solution into the cathode chamber 5c and a cathode electrolyte solution outlet 5co for extracting the electrolyte solution derived from the cathode chamber 5c.

  And the bipolar battery unit 50 in this embodiment is equipped with the header 10 connected to the electrode chamber 5 in the outer side of the outer frame 3 (refer FIG. 2, FIG. 3).

In the example shown in FIG. 2 and FIG. 3, the header 10 which is a pipe for distributing or collecting a gas or an electrolytic solution is attached to the bipolar electrolytic cell 50. Specifically, the header 10 comprises an inlet header for introducing the electrolyte into the electrode chamber 5 and an outlet header for discharging the gas and the electrolyte from the electrode chamber 5.
In one example, an anode inlet header 10 Oai for putting the electrolyte into the anode chamber 5 a and a cathode inlet header 10 Oci for putting the electrolyte into the cathode chamber 5 c are provided under the outer frame 3 at the edge of the partition 1. Similarly, on the side of the outer frame 3 at the edge of the partition wall 1, an anode outlet header 10Oao for discharging the electrode solution from the anode chamber 5a and a cathode outlet header 10Oco for discharging the electrolyte solution from the cathode chamber 5c are provided. .
Further, in one example, in the anode chamber 5 a and the cathode chamber 5 c, the inlet header and the outlet header are provided to face each other across the central portion of the electrode chamber 5.

In particular, the bipolar electrolyzer 50 of this example adopts an outer header 10 O type in which the bipolar electrolyzer 50 and the header 10 are independent.
FIG. 4 is a plan view showing an example of the external header type bipolar electrode type electrolytic cell for alkaline water electrolysis of the present embodiment.

  As a mode of disposition of the header 10 attached to the bipolar electrolytic cell shown in FIGS. 1 to 3, typically, there are an inner header 10I type and an outer header 10O type. A mold may be adopted and is not particularly limited.

Furthermore, in the example shown in FIG. 2 and FIG. 3, the conduit 10 is attached to the header 10, which is a pipe for collecting the gas or the electrolyte supplied or collected in the header 10. In particular, the conduit 20 consists of a distribution tube in communication with the inlet header and a collection tube in communication with the outlet header.
In one example, the lower side of the outer frame 3 is provided with an anode liquid distribution pipe 20Oai in communication with the anode inlet header 10Oai and a cathode liquid distribution pipe 20Oci in communication with the cathode inlet header 10Oci. And an anode liquid collection pipe 20Oao communicating with the anode outlet header 10Oao and a cathode liquid collection pipe 20Oco communicating with the cathode outlet header 10Oco on the side of the outer frame 3.

  In the present embodiment, in the anode chamber 5a and the cathode chamber 5c, the inlet header and the outlet header are preferably provided at remote positions from the viewpoint of water electrolysis efficiency, and face each other across the central portion of the electrode chamber 5 If the plan view shape of the partition wall 1 is rectangular as shown in FIG. 2 and FIG. 3, it is preferable to be provided so as to be symmetrical with respect to the center of the rectangle.

Generally, as shown in FIGS. 2 and 3, one anode inlet header 10Oai, one cathode inlet header 10Oci, one anode outlet header 10Oao and one cathode outlet header 100oco are provided in each electrode chamber 5, but in this embodiment, Not limited to this, a plurality of electrodes may be provided in each electrode chamber 5.
In addition, although generally one liquid distribution pipe 20 Oai for anode, liquid distribution pipe 20 Oci for cathode, liquid collection pipe 20Oao for anode, and liquid collection pipe 20Oco for cathode are provided one by one in each electrode chamber 5, in this embodiment, The invention is not limited to this, and a plurality of electrode chambers 5 may be shared.

  In the illustrated example, the rectangular partition 1 in plan view and the rectangular partition 4 in plan view are arranged in parallel, and the partition 1 side of the rectangular outer frame provided at the edge of the partition 1 Since the inner surface of the electrode is perpendicular to the partition wall 1, the shape of the electrode chamber 5 is a rectangular parallelepiped. However, in the present invention, the shape of the electrode chamber 5 is not limited to the rectangular solid in the illustrated example, but the shapes of the partition 1 and the diaphragm 4 in plan view, the inner surface of the outer frame 3 on the partition 1 side and the partition 1 Depending on the angle or the like, the shape may be modified as appropriate, as long as the effects of the present invention can be obtained.

  In the present embodiment, the extending direction of the header 10 is not particularly limited.

  In the present embodiment, the extending direction of the conduit 20 is not particularly limited, but as in the example shown in FIG. 2 and FIG. 3, from the viewpoint of easily obtaining the effect of the present invention The pipe 20Oai, the cathode liquid distribution pipe 20Oci) and the liquid collection pipe (an anode liquid collection pipe 20Oao, a cathode liquid collection pipe 20Oco) preferably extend in a direction perpendicular to the partition wall 1, respectively. It is further preferable that all of them extend in the direction perpendicular to the partition wall 1.

  Sometimes, the electrolysis cell 65 produces a self-discharge reaction through the leakage current circuit formed by the electrolyte supply pipe at the time of the electrolysis stop.

  Even when the self-discharge occurs, a structure having an electric capacity for holding the cell voltage of the electrolytic cell 65 is called a charge holder. The charge carrier can be electrically connected to the cathode 2c or the anode 2a inside the cathode chamber 5c or the anode chamber 5a, and the electrochemical potential of the cathode 2c or the anode 2a can be stabilized for a long time. The electrolytic cell can be used as an emergency storage battery when the power supply is stopped.

  In the present embodiment, the cathode 2c or the anode 2a is composed of a catalyst layer and a base material supporting the catalyst layer, and the catalyst layer or base material has the function of the charge carrier.

Here, in the bipolar electrolytic cell 50 for alkaline water electrolysis of the present embodiment, the electric capacity of the anode 2a is in the range of 4825 C / m ^{2 to} 965000 C / m ² (0.05 Fd / m ^{2 to} 10 Fd / m ² ). The electric capacity of the cathode 2c is in the range of 4825 C / m ^{2 to} 965000 C / m ² (0.05 Fd / m ^{2 to} 10 Fd / m ² ).

  During operation with a fluctuating power source such as renewable energy, the function of the charge holder in the electrode chamber 5 increases and balances the amount of electricity held in the electrolytic cell, and further improves the structure of the electrolyte supply pipe, By reducing the self-discharge generated when the power supply is stopped, the electrolytic cell can be used as an emergency storage battery when the power supply is stopped, and the electrical control system can be stabilized even in an emergency.

In the present embodiment, in view of enhancing the effect of the present invention, the capacitance of the anode 2a ^is more preferably in a range of ^{9650C / m 2 ~772000C / m 2} , the range of 48250C / ^{m 2} ~482500C / m 2 It is most preferable that Capacitance of the cathode 2c ^is more preferably in a range of ^{9650C / m 2 ~772000C / m 2} , and most preferably in the range of ^{48250C / m 2 ~482500C / m 2} .

In the bipolar electrolytic cell 50 for alkaline water electrolysis of the present embodiment, the lower one of the electric capacity of the anode 2a and the electric capacity of the cathode 2c is preferably in the range of 9650C / m ^{2 to} 955350C / m ² , 48250C / The range of m ^{2 to} 772000 C / m ² is more preferable, and the range of 96500 C / m ^{2 to} 482500 C / m ² is particularly preferable.
If the lower one of the electric capacities is too small, it will be difficult to function as a power source, and if the lower one of the electric capacities is too large, substantial fabrication will become difficult.

  In the bipolar electrolytic cell 50 for alkaline water electrolysis of the present embodiment, the electric capacity of the anode is preferably larger than the electric capacity of the cathode. In that case, the ratio of the electric capacity of the cathode to the electric capacity of the anode is 0 It is preferable to be in the range of more than 1 × and 0.99 times or less, and more preferable to be in the range of more than 0.1 × and 0.49 times or less.

  An electrode complex (anode complex, cathode complex) including the conductive elastic body 2e and the current collector 2r in addition to the electrode 2 (anode 2a, cathode 2c) in addition to the electrode 2 (anode 2a, cathode 2c) In the case where is used, the above-mentioned electric capacity may be determined for the electrode complex (anode complex, cathode complex).

  The above-described effects of the present invention are less subject to physical restrictions regarding the header design, and it is structurally easy to shut off the discharge line (outlet header) of the electrolyte on the electrolyte outlet 5 o side when the electrolysis is stopped. It is easy to be obtained in the alkaline water electrolysis cell of the external header 10 O type in which the supply header of the electrolytic solution to each electrolysis cell 65 is disposed outside the electrolysis cell 65.

In the bipolar electrolyzer 50 for alkaline water electrolysis according to this embodiment, the area of the current-carrying surface of the bipolar element 60 is S1, the cross-sectional area of the flow passage of the header 10 is S2, and the flow passage length of the header 10 is L2. (S2 / S1) / L2 is preferably in the range of 1.5 × 10 ⁻⁶ m ^{−1 to} 2.3 × 10 ⁻⁴ m ⁻¹ , and 4.0 × 10 ⁻⁶ m It is more preferably in the range of ^{−1 to} 2.0 × 10 ⁻⁴ m ⁻¹ , particularly preferably in the range of 8.0 × 10 ⁻⁶ m ^{−1 to} 1.0 × 10 ⁻⁴ m ⁻¹ preferable.

The area S1 of the current-carrying surface of the bipolar element 60 refers to the area in a plane parallel to the partition walls of the electrodes (anode 2a and cathode 2c) of the bipolar element 60. In addition, when the said area differs in the anode 2a and the cathode 2c, the average shall be said.
The cross-sectional area S2 of the flow path of the header 10 refers to the cross-sectional area of the inner space of the header 10 through which the electrolyte passes. In addition, when a cross-sectional area changes with respect to the extension direction of the header 10, the average of the cross-sectional area shall be said. In addition, when the cross-sectional areas of the anode inlet header 10 Oai, the cathode inlet header 10 Oci, the anode outlet header 10 Oao, and the cathode outlet header 10 Oco are different, the average of the cross sections is used.
The length L2 of the flow path of the header 10 refers to the extension length of the internal space of the header 10 through which the electrolytic solution passes. In particular, in the case of including the conduit 20 in communication with the header 10, it is from the electrolyte inlet 5i of the header 10 to the connection portion with the liquid distribution pipe (conduit 20), or with the liquid collection pipe (conduit) from the electrolyte outlet 5o. The length of the part up to the connection part. Further, when the lengths of the anode inlet header 10Oai, the cathode inlet header 10Oci, the anode outlet header 10Oao, and the cathode outlet header 10Oco differ, the average of the lengths is used.

  If (S2 / S1) / L2 is in the above range, self-discharge generated when the power supply is stopped can be reduced, and stabilization of the electrical control system becomes possible, and storage of power with high efficiency, specifically In fact, it is possible to realize hydrogen production with high efficiency by reducing the leakage current.

Furthermore, the alkaline water electrolysis a bipolar type electrolytic cell 50 of the present embodiment, the area S1 of the energizing surface of Fukukyokushiki element 60 ^is preferably a 0.1m ² ~10m 2, 0.15m 2 ~8m further preferably ^2, particularly preferably 0.2m ² ~5m ^2.
If the current-carrying surface is too small, the electrolytic solution supply header will also be small, making it difficult to manufacture the electrolytic cell 50. Also, if the current-carrying surface is too large, the seal surface pressure is likely to be uneven, which may cause leakage of the electrolyte and gas leakage.

Furthermore, in the bipolar electrolytic cell 50 for alkaline water electrolysis of the present embodiment, the thickness d of the electrolytic cell 65 is preferably 10 mm to 100 mm, more preferably 15 mm to 50 mm, and 20 mm to 40 mm. Being particularly preferred.
The thickness d of the electrolytic cell 65 refers to the thickness of the portion between the adjacent partitions 1 between the two bipolar elements 60, and between the adjacent bipolar elements 60 and the terminal elements 51a and 51c. The thickness of the portion between the partitions 1 of each other, the distance in the direction perpendicular to the partitions 1 between the partitions 1 of two adjacent bipolar elements 60, and the adjacent bipolar The distance in the direction perpendicular to the partition 1 between the partition 1 of the element 60 and the partition 1 of the terminal elements 51a, 51c. If the thickness d is not constant throughout the bipolar electrolytic cell 50, the average may be said.
If the thickness d of the electrolytic cell is too small, the gas ratio in the gas liquid chamber of the electrolytic cell 65 tends to increase, and the cell voltage tends to increase. If the thickness d is too large, uniform distribution becomes difficult due to the pressure loss of the header 10, and the installation area becomes too large.

Furthermore, in the bipolar electrolyzer 50 for alkaline water electrolysis according to the present embodiment, S2 is used from the viewpoint of further purifying the gas purity and from the viewpoint of suppressing channel blockage due to solids present in the circulation channel. 7.00 × 10 ⁻⁷ m ^{2 to} 3.14 × 10 ⁻⁴ m ² , preferably 1.0 × 10 ⁻⁶ m ^{2 to} 2.0 × 10 ⁻⁴ m ² preferable.

  Furthermore, in the bipolar electrolytic cell 50 for alkaline water electrolysis of the present embodiment, although not particularly limited, L2 is 0.2 m to 10 m from the same viewpoint as the case of the preferred range of S2. Is preferably, and more preferably 0.4 m to 8 m.

The bipolar electrolytic cell 50 for alkaline water electrolysis according to this embodiment preferably has 50 to 500 bipolar elements 60, and more preferably 70 to 300, and 100 to 200. It is particularly preferred to have the bipolar element 60 of
If it is less than the lower limit, the ratio of the tightening mechanism to the cell becomes relatively large, so that the manufacturing cost increases and the installation area of the facility increases, which may make it impossible to be a realistic facility. In the case of exceeding the upper limit, the effect of enabling the stabilization of the electrical control system by reducing the self-discharge generated when the power supply is stopped, and the storage of the power with high efficiency, specifically, the pump It becomes difficult to parallelize the effects that make it possible to realize the reduction of power and the reduction of leakage current.
In addition, if the number (logarithm) of the bipolar elements 60 increases excessively, there is a possibility that the manufacture of the electrolytic cell 50 may become difficult, and in the case where a large number of the bipolar elements 60 having poor manufacturing accuracy are stacked, the seal surface pressure Is likely to be uneven, resulting in electrolyte leakage and gas leakage.

Hereinafter, the components of the bipolar electrolyzer 50 for alkaline water electrolysis of the present embodiment will be described in detail.
Also, in the following, preferred embodiments for enhancing the effects of the present invention will be described in detail.

-Bulkhead-
The shape of the partition wall 1 in the present embodiment may be a plate-like shape having a predetermined thickness, but is not particularly limited.
The shape of the partition wall 1 in plan view is not particularly limited, and may be rectangular (square, rectangular, etc.) or circular (circle, oval, etc.), and the rectangle may have rounded corners.
In one embodiment, the partition wall 1 and the outer frame 3 may be integrated by welding or other method, and for example, a flange portion projected in the direction perpendicular to the plane of the partition wall 1 An anode flange portion projected to the anode 2 a side and a cathode flange portion projected to the cathode 2 c side may be provided, and the flange portion may be a part of the outer frame 3.

  In addition, the partition 1 may be used so that a given direction D1 along the partition 1 is usually in the vertical direction. Specifically, as shown in FIG. 2 and FIG. If the shape is rectangular, it may be used such that a given direction D1 along the partition 1 is in the same direction as the direction of one of the two sets of opposite sides. And in this specification, the above-mentioned perpendicular direction is also called an electrolysis solution passage direction.

  The material of the partition 1 is preferably a material having conductivity from the viewpoint of achieving uniform supply of electric power, and nickel plating is applied on nickel, nickel alloy, mild steel and nickel alloy from the viewpoint of alkali resistance and heat resistance. Are preferred.

-Electrode-
In the hydrogen production by alkaline water electrolysis of the present embodiment, the reduction of energy consumption, specifically the reduction of the electrolysis voltage, is a major issue. The performance of both electrodes 2 is important because this electrolytic voltage depends largely on the electrode 2.

  The electrolysis voltage of alkaline water electrolysis is not only the voltage required for electrolysis of water theoretically calculated, but also the overvoltage of the anodic reaction (oxygen generation), the overvoltage of the cathodic reaction (hydrogen generation), and that of the anode 2a and the cathode 2c. It is divided into a voltage due to the distance between the electrodes 2. Here, the term "overvoltage" refers to a voltage that needs to be applied in excess of the theoretical decomposition potential when a certain current flows, the value of which depends on the current value. When flowing the same current, power consumption can be reduced by using the electrode 2 with a low over voltage.

  In order to realize low overvoltage, the requirements for the electrode 2 include high conductivity, high ability to generate oxygen (or ability to generate hydrogen), high wettability of the electrolyte on the surface of the electrode 2, etc. It can be mentioned.

  As the electrode 2 of alkaline water electrolysis, in addition to low overvoltage, corrosion of the base material of the electrode 2 and the catalyst layer, detachment of the catalyst layer, and electrolyte solution even when using unstable current such as renewable energy It is difficult to cause dissolution, adhesion of inclusions to the diaphragm 4, and the like.

  The structure of the conductive substrate of the anode and the cathode is preferably a mesh structure in terms of securing a specific surface area as a carrier and degassing. The material of the conductive substrate may be at least one selected from the group consisting of nickel iron, vanadium, molybdenum, copper, silver, manganese, a platinum group, graphite, chromium and the like. An alloy of two or more metals or a mixture of two or more conductive materials may be used for the conductive substrate. It is preferable to use metallic nickel as the conductive substrate.

-Anode--
The anode 2a includes a conductive base and a catalyst layer for coating the conductive base, and the catalyst layer is preferably a porous body. The catalyst layer preferably covers the entire surface of the conductive substrate.

  The catalyst layer of the anode preferably contains nickel as an element, in terms of durability against alkali and high activity against oxygen generation. The catalyst layer preferably contains at least one nickel compound selected from nickel oxide, metallic nickel, nickel hydroxide and a nickel alloy.

Real electrode surface area of the geometric cell area 1 m ² per per one anode (actual specific surface area) is preferably in the range of 90~10000m ^2. If the actual electrode surface is less than 90 m ² / m ² , the surface area of the entire catalyst layer is small, so it is expected that the oxygen overvoltage will be high. In addition, when the actual electrode surface exceeds 10000 m ² / m ² , the catalyst layer is very fragile because it contains fine pores, and the durability is poor, and it is expected that the oxygen overvoltage will increase with the generation of oxygen. .
The geometric cell area refers to the area when the electrolysis cell 65 is projected in the direction perpendicular to the partition wall 1.
The real electrode surface per the area 1 m ^2, more preferably in the range of 500~8000m ² / ^{m 2,} and particularly preferably in the range of 1000~5000m ² / ^{m 2.}

Among the pores in the catalyst layer of the anode, the specific surface area of the first pore having a pore size in the range of ² to 5 nm is 0.6 to 2.0 m ² / g, and the pores of the first pore The volume is preferably 3 × 10 ^{−4 to} 9 × 10 ⁻⁴ ml / g. Among the pores in the catalyst layer, the specific surface area of the second pore whose pore diameter is in the range of 0.01 to 2.00 μm is 2.0 to 5.0 m ² / g, and The pore volume is preferably 0.04 to 0.2 ml / g.
The thickness of the catalyst layer is preferably 50 to 800 μm, and more preferably 100 to 400 μm.

  Although the second pore having a pore diameter in the range of 0.01 to 2.00 μm has a small specific surface area, the first pore is present on the inner wall of the second pore because the pore volume is large. Become. The first pores make the surface area of the catalyst layer very large. The surface of the first pore functions as a reaction field (reaction interface) of the oxidation reaction (formation reaction of oxygen) of hydroxide ions. Inside the first pore, nickel hydroxide is formed during oxygen evolution, which is expected to make the pore smaller. However, since the first pore is present inside the second pore having a large pore diameter, oxygen generated in the first pore is likely to escape out of the catalyst layer through the second pore, and it is difficult to inhibit the electrolysis. . Therefore, in the present embodiment, it is estimated that the oxygen generation overvoltage is difficult to increase at the time of electrolysis.

Preferably the specific surface area of the first pores is 0.6~1.5m ² / g, more preferably 0.6~1.0m ² / g. The specific surface area of the first pores may be 0.62 to 0.98 m ² / g. In general, it is considered that the oxygen generation potential decreases as the specific surface area of the first pore increases. However, if the first pores are too small, the first pores are completely filled with nickel hydroxide formed at the time of oxygen generation, and the substantial surface area of the first pores tends to be reduced. As the specific surface area of the first pores decreases, the surface area of the entire catalyst layer also tends to decrease. As the surface area of the entire catalyst layer decreases, the oxygen generation potential tends to increase.

The volume of the first pore is preferably 3.3 × 10 ^{−4 to} 8.5 × 10 ⁻⁴ ml / g. Volume of the first pores may be ^{3.6 × 10 -4 ml / g~7.9 ×} 10 -4 ml / g. As the pore volume of the first pore increases, the specific surface area tends to decrease. As the pore volume of the first pore decreases, the specific surface area of the entire catalyst layer tends to increase.

The specific surface area of the second pores is preferably 2.3 to 4.5 m ² / g. The specific surface area of the second pores may be 2.5 to 4.2 m ² / g. The pore volume of the entire catalyst layer tends to decrease as the specific surface area of the second pores increases. In addition, the pore volume of the entire catalyst layer tends to increase as the specific surface area of the second pores decreases.

  The volume of the second pores is preferably 0.04 to 0.15 ml / g, more preferably 0.04 to 0.1 ml / g. The volume of the second pore may be 0.04 to 0.09 ml / g. As the pore volume of the second pore increases, the oxygen gas generated in the catalyst layer tends to degas. As the pore volume of the second pore decreases, the oxygen gas generated in the catalyst layer tends to be difficult to degas, and the oxygen generation overvoltage tends to increase. On the other hand, the mechanical strength of the catalyst layer tends to increase as the pore volume of the second pore decreases.

  If the thickness is less than 50 μm, it is expected that the surface area of the entire catalyst layer will be small and the oxygen overvoltage will be high because the catalyst layer is thin. If the thickness is more than 800 μm, the catalyst layer may be too thick, which may easily cause peeling or the like, and the cost of manufacturing the anode may be too high.

The catalyst layer contains metal crystals of nickel, and the peak intensity of X-rays diffracted by the (1,1,1) plane of the metal crystals of nickel in the catalyst layer is I _Ni; It is preferable that the value of [I _Ni / (I _Ni + I _{NiO 2} )] × 100 is 75 to 100% when the peak intensity of the X-ray diffracted by the (1, 1, 2) plane is I _NiO . The ratio of I [I _Ni / (I _Ni + I _NiO )] × 100 is more preferably 90 to 100%, and particularly preferably 95 to 100%.

The larger the [I _Ni / (I _Ni + I _NiO )] × 100, the lower the electrical resistance of the catalyst layer and the smaller the voltage loss during oxygen generation. The conductivity of the nickel oxide portion in the catalyst layer is lowered, but the oxygen generation reaction is also less likely to occur. In addition, since nickel oxide is relatively excellent in chemical stability, containing nickel oxide in the catalyst layer may be effective for maintaining the strength of the catalyst layer. In addition, I _Ni and I _NiO can be obtained from the measurement results of XRD ((X-Ray Diffraction)) of the catalyst layer.

  The catalyst layer may contain an alloy composed of nickel and another metal. The catalyst layer is particularly preferably made of metallic nickel. It may further contain at least one selected from the group consisting of titanium, chromium, molybdenum, cobalt, tantalum, zirconium, aluminum, zinc, a platinum group, a rare earth element, and the like. In addition, the surface of the catalyst layer may be modified with at least one catalyst selected from the group consisting of rhodium, palladium, iridium, ruthenium and the like.

--Manufacturing method of anode for alkaline water electrolysis--
The manufacturing method of the anode for alkaline water electrolysis according to the present embodiment is not particularly limited. As a preferable manufacturing method, Raney nickel is covered by dispersion plating using expanse nickel as a base material, and the method of developing with 32 wt% alkali is mentioned.

--Cathode--
The cathode 2c is not particularly limited. Containing at least one Pt group compound selected from the group consisting of Ru-La-Pt system, Ru-Ce system, Pt-Ce system, Pt-Ir system, Ir-Pt-Pd system, Pt-Ni system Is preferred. Moreover, it is preferable that it is a thermal decomposition type active cathode. The structure of the base material of the cathode is preferably a mesh structure in terms of securing a specific surface area as a carrier and degassing.

  The catalyst layer of the cathode preferably contains nickel as an element in terms of durability against alkali and high activity against hydrogen generation. The catalyst layer preferably contains at least one nickel compound selected from nickel oxide, metallic nickel, nickel hydroxide and a nickel alloy.

In particular, it is preferable that the base material of the cathode has a linear range of 0.05 to 0.5 mm, and the openings have a range of 30 mesh to 80 mesh. Within this range, the specific surface area required for the carrier and the degassing property can be exhibited while maintaining the mechanical strength of the mesh as the cathode. By setting the opening ratio of the mesh of the conductive substrate of the anode to be in the range of 20% to 60%, the specific surface area necessary for the carrier and the degassing property can be developed while maintaining the mechanical strength of the mesh.
The aperture ratio of the electrode can be measured by the following method.
An electrode made of expanded metal as a base material is cut out to a size of about 5 mm × 5 mm, and using a bench-top microscope MiniscopeTM 3000 (manufactured by Hitachi High-Technologies Corporation), center-to-center distance SW in the short direction and center distance in the long direction The LW, the bond length B, the single direction length SWO of the opening, and the long direction length LWO of the opening were measured. The aperture ratio was calculated according to the following equation using these values.
Aperture ratio = SWO x (LWO + B) x 100 / (SW x LW)
Moreover, the electrode which used the plain weave mesh as a base material similarly measured the opening A and the wire diameter d using TM3000, and calculated the aperture ratio (%) according to the following formula.
Aperture ratio = (A / (A + d)) ² × 100
The calculation method of the aperture ratio of an electrode differs by the electrode which made the expanded metal the base material, and the electrode which made the plain weave mesh the base material. In addition, the aperture ratio of the electrode which used expanded metal and plain weave mesh as a base material cut out an electrode into a predetermined size (for example, about 5 mm x 5 mm), and was left still from the vertical direction upper side of the central part of the electrode. Light is projected, the electrode is projected vertically downward, and the total area of the part where light is transmitted and the projected area of the electrode (the sum of the area of the shadow and the transmitted light) are measured and calculated according to the following equation be able to.
Aperture ratio = (total area of light transmitting portion) / (projected area of electrode) × 100

--Manufacturing method of cathode for alkaline water electrolysis--
The method of manufacturing the cathode for alkaline water electrolysis according to the present embodiment may be the same as the method of manufacturing the anode described above.

-Outer frame-
The shape of the outer frame 3 in the present embodiment is not particularly limited as long as the partition wall 1 can be edged.

-Diaphragm-
As the diaphragm 4 used in the bipolar electrolytic cell 50 for alkaline water electrolysis of the present embodiment, the ion-permeable diaphragm 4 is used to separate hydrogen gas and oxygen gas generated while conducting ions. Ru. The ion-permeable diaphragm 4 may be an ion exchange membrane having ion exchange ability and a porous membrane capable of permeating the electrolyte. The ion-permeable diaphragm 4 preferably has low gas permeability, high ion conductivity, low electron conductivity, and high strength.

-Electrode chamber-
In the bipolar electrolyzer 50 in the present embodiment, as shown in FIG. 2, the partition 1, the outer frame 3 and the diaphragm 4 define an electrode chamber 5 through which the electrolyte passes.

-Gasket-
In the bipolar electrolytic cell 50 for alkaline water electrolysis of the present embodiment, it is preferable that the gasket 7 having the diaphragm 4 be held between the outer frames 3 bordering the partition wall 1.
The gasket 7 is used to seal between the bipolar element 60 and the diaphragm 4 and between the bipolar element 60 with respect to the electrolytic solution and the generated gas, and leakage of the electrolytic solution and the generated gas to the outside of the electrolytic cell It is possible to prevent gas mixing between the two electrode chambers.

-Charge holder-
In the bipolar electrolytic cell 50 for alkaline water electrolysis according to this embodiment, as shown in FIG. 2, the conductive elastic body 2 e and the current collector 2 r are electrically conductive between the cathode 2 c or the anode 2 a and the partition wall 1. The elastic body 2e is provided so as to be sandwiched between the cathode 2c or the anode 2a and the current collector 2r, and forms an electrolytic support.
The charge carrier preferably contains nickel as a base, from the viewpoint that the resistance to alkali is high, the redox potential is a monument with respect to the anode, and the anode can be reduced at the time of termination of the electrolysis. The base may contain at least one selected from nickel oxide, metallic nickel, nickel hydroxide and a nickel alloy.

  The cathode chamber further encloses the conductive elastic body 2e and the current collector 2g, and the conductive elastic body 2e is compressed and housed in a state of being electrically connected between the cathode chamber and the current collector. A part of the cathode current collector may be constituted by the charge carrier. This makes it possible to suppress the increase in cell weight due to the additional attachment of the charge carrier.

  The surface layer of the charge carrier preferably further contains nickel as an element. The surface layer preferably contains at least one selected from the group consisting of nickel oxide, metallic nickel (metal crystals of nickel), nickel hydroxide and the like. The surface layer may include an alloy composed of nickel and other metals. It is particularly preferred that the surface layer consists of metallic nickel. The surface layer may further contain at least one selected from the group consisting of titanium, chromium, molybdenum, cobalt, tantalum, zirconium, aluminum, zinc, a platinum group, a rare earth element, and the like.

  The method for producing the charge carrier is not particularly limited, but includes the same production method as that for the anode.

-Header-
The alkaline water electrolysis bipolar electrolyzer 50 has a cathode chamber 5 c and an anode chamber 5 a for each electrolysis cell 65. In order to carry out the electrolysis reaction continuously in the electrolytic cell 50, it is necessary to continue supplying an electrolytic solution containing a material sufficiently consumed by the electrolysis to the cathode chamber 5c and the anode chamber 5a of each electrolysis cell 65 There is.

  The electrolysis cell 65 is connected to an electrolyte supply / discharge pipe called a header 10 common to the plurality of electrolysis cells 65. Generally, the anode fluid distribution tube is called an anode inlet header 10ai, the cathode fluid distribution tube is called a cathode inlet header 10ci, the anode fluid collection tube is called an anode outlet header 10ao, and the cathode fluid collection tube is called a cathode outlet header 10co. The electrolysis cell 65 is connected to the liquid distribution pipe for each electrode and the liquid collection pipe for each electrode through a hose or the like.

  The material of the header 10 is not particularly limited, but it is necessary to adopt one that can sufficiently withstand the corrosiveness of the electrolyte to be used and the operating conditions such as pressure and temperature. As the material of the header 10, iron, nickel, cobalt, PTFE, ETFE, PFA, polyvinyl chloride, polyethylene or the like may be adopted.

  In the present embodiment, the range of the electrode chamber 5 varies depending on the detailed structure of the outer frame 3 provided at the outer end of the partition wall 1. The detailed structure of the outer frame 3 is the header 10 attached to the outer frame 3 It may differ depending on the arrangement of the tubes for liquid distribution or collection. As a disposition mode of the header 10 of the bipolar electrolytic cell 50, an inner header 10I type and an outer header 10O type are representative.

-Inner header-
The internal header 10I type refers to a type in which the bipolar electrolytic cell 50 and the header 10 (a pipe for supplying or collecting an electrolytic solution) are integrated.

  More specifically, in the inner header 10I type bipolar electrolytic cell 50, the anode inlet header 10Iai and the cathode inlet header 10Ici are provided in the lower portion in the partition 1 and / or in the outer frame 3, and in the partition 1 It is provided to extend in the vertical direction, and an anode outlet header 10Iao and a cathode outlet header 10Ico are provided at the top in the partition 1 and / or the outer frame 3 and in the direction perpendicular to the partition 1 It is provided to extend.

  An anode inlet header 10Iai, a cathode inlet header 10Ici, an anode outlet header 10Iao, and a cathode outlet header 10Ico inherently included in the inner header 10I type bipolar electrolytic cell 50 are collectively referred to as an inner header 10I.

  In the example of the inner header 10I type shown in FIGS. 4 and 5, the anode inlet header 10Iai and the cathode inlet header 10Ici are provided on a part of the lower part of the outer frame 3 at the edge of the partition 1 Similarly, in a part of the upper portion of the outer frame 3 at the end edge of the partition wall 1, an anode outlet header 10Iao and a cathode outlet header 10Ico are provided.

-Outer header-
The external header 10O type refers to a type in which the bipolar electrolyzer 50 and the header 10 (a pipe for supplying or collecting an electrolytic solution) are independent.

  The external header 10 O type bipolar electrolytic cell 50 is independent of the anode inlet header 10 Oai and the cathode inlet header 10 Oci in parallel with the electrolytic cell 50 in a direction perpendicular to the current-carrying surface of the electrolytic cell 65. Provided. Each of the electrolytic cells 65 is connected by a hose to the anode inlet header 10Oai and the cathode inlet header 10Oci.

Anode inlet header 10Oai, cathode inlet header 10Oci, anode outlet header 10Oao, and cathode outlet header 10Oco, which are externally connected to the outer header 10O type bipolar electrolytic cell 50, are collectively referred to as the outer header 10O Call.
In the example of the outer header 10O type, a tubular member is installed in the through hole for the header 10 provided in the lower part of the outer frame 3 at the edge of the partition wall 1, and the tubular member is , Through-holes for header 10 provided in an upper portion of outer frame 3 at the edge of partition 1 connected to anode inlet header 10 Oai and cathode inlet header 10 Oci. A tubular member (for example, a hose, a tube, etc.) is installed, and such a tubular member is connected to the anode outlet header 10Oao and the cathode outlet header 100oco.

(Electrolyzer for alkaline water electrolysis)
The outline | summary of the electrolyzer for alkaline water electrolysis of this embodiment is shown in FIG.
By using the bipolar water electrolytic cell of the present embodiment as an electrolysis apparatus including other elements as a hydrogen production apparatus, a hydrogen production apparatus having high electrolysis efficiency can be provided.
The electrolytic device for alkaline water electrolysis of the present embodiment includes at least a bipolar water electrolytic tank 50 of the present embodiment, a gas-liquid separation tank 72 (hydrogen separation tank 72 h, oxygen separation tank 72 o), an electrolyte circulation pump 71, water A charge pump 73 and a rectifier 74 for supplying power for electrolysis are provided.
The electrolysis apparatus 70 for alkaline water electrolysis of this embodiment may be equipped with an oximeter 75, a hydrogen concentration meter 76, a flow meter 77, a pressure gauge 78, a heat exchanger 79, and a pressure control valve 80 besides the above.

According to the alkaline water electrolysis electrolytic device 70 of the present embodiment, the effects of the alkaline water electrolysis bipolar electrolytic cell of the present embodiment can be obtained.
That is, according to the present embodiment, it is possible to realize hydrogen production with high efficiency at the time of operation with a fluctuating power source such as renewable energy, and reduce self-discharge generated when power supply is stopped, It is possible to stabilize the electrical control system. According to this embodiment, it is further possible to realize storage of power with high efficiency, specifically, reduction of pump power and reduction of leakage current.

(Alkaline water electrolysis method)
The alkaline water electrolysis method of this embodiment can be implemented using the electrolysis apparatus 70 for alkaline water electrolysis of this embodiment.

  As described above, the bipolar electrode electrolytic cell for alkaline water electrolysis, the electrolytic device for alkaline water electrolysis, and the alkaline water electrolysis method of the embodiment of the present invention have been described with reference to the drawings, but the bipolar electrode for alkaline water electrolysis of the present invention The type electrolytic cell, the electrolytic device for alkaline water electrolysis, and the alkaline water electrolysis method are not limited to the examples described above, and appropriate modifications can be made to the above embodiment.

  Hereinafter, the present invention will be described in more detail by way of examples, but the present invention is not limited to the following examples.

  A bipolar cell for alkaline water electrolysis and an alkaline water electrolysis apparatus using the same were produced as follows.

-Bulkhead, outer frame-
As the bipolar element, one provided with a partition separating an anode and a cathode and an outer frame 3 surrounding the partition was used. The material of the members in contact with the electrolytic solution such as the partition walls and the frame of the bipolar element was all nickel.

-Anode-
Blasting was performed using an expanded nickel aperture ratio of 50% as a conductive substrate. The conductive base material was adjusted to 50 cm square by cutting, and was used as an anode sample A.
The anode sample A was immersed in a 5 N HCl aqueous solution for 10 minutes to obtain an anode sample B.
The anode sample B was used to coat a Raney nickel alloy by dispersion plating, and immersed in a 32 wt% aqueous NaOH solution at 80 ° C. for 10 hours to dissolve Al in the Raney nickel alloy. An anode sample C was obtained by the above process.
Six anode samples C were stacked and stacked, and anode samples D were prepared so as to be at the same potential.
Anode samples E were prepared by stacking eight anode samples C in layers and connecting them so as to have the same potential.

  Blasting was performed using expanded nickel as a conductive substrate. In the same manner as described above, the conductive base material was adjusted to 50 cm square by cutting, and was used as an anode sample A. As described above, the anode sample A was immersed in a 5N HCl aqueous solution for 10 minutes to obtain an anode sample B. The anode sample B was used to coat the Raney nickel alloy by dispersion plating for 8 times the time of the anode sample C, and immersed in a 32 wt% aqueous NaOH solution at 80 ° C. for 10 hours to dissolve Al in the Raney nickel alloy. An anode sample F was obtained by the above process.

((Measurement of anode (oxygen electrode) potential of anode sample))
One anode sample A, B, C, D, E, F was prepared, and immersed in a fluororesin beaker filled with an electrolyte solution of 30 wt% KOH. The temperature of the aqueous solution of KOH was maintained at 90.degree. Anodized sample, platinum wire mesh (counter electrode) and a tube of fluorocarbon resin covering the periphery of the counter electrode, in a device in which the electric conductivity is ensured, oxidation of a current density of 0.4 A / cm ² to the anode sample An electric current was applied to generate hydrogen for 30 minutes. Thereafter, a reduction current of 0.05 A / cm ² was applied to measure the change in potential of the anode sample. This potential change was plotted against the total amount of retained charge (capacitance) of the flowed current to obtain an oxidation curve of the anode sample.

  The measurement was performed at a temperature of 90 ° C., using a mesh-like platinum electrode as a counter electrode. As the fluorocarbon resin cylinder, one having a large number of holes of 1 mm in diameter was used. The anode potential of the anode sample was measured by a three-electrode method using a Lugin tube to eliminate the influence of ohmic loss due to liquid resistance. The distance between the tip of the Luggin tube and the anode was always fixed at 0.05 mm. Silver-silver chloride (Ag / AgCl) was used as a reference electrode for the three-electrode method.

((Measurement of the amount of positive charge (electric capacity) stored in the anode (oxygen electrode) chamber when oxygen is generated))
In the reduction curves of the anode samples measured for the anode samples A, B, C, D, E, and F, the total charge of the current flowed until the anode potential became 0 V (vs Ag / AgCl) was generated by oxygen The positive charge amount (electric capacity) (C / m ² ) that is sometimes stored in the anode chamber is used.

The positive charge amount (electric capacity) of the anode sample A was 3667 C / m ² . The positive charge amount (capacitance) of the anode sample B was 5018 C / m ² . The positive charge amount (capacitance) of the anode sample C was 148,610 C / m ² . The amount of positive charge (capacitance) of the anode sample D was 955,350 C / m ² . The amount of positive charge (capacitance) of the anode sample E was 106,1500 C / m ² . The positive charge amount (capacitance) of the anode sample F was 445,830 C / m ² .

The actual specific surface area per anode of anode samples A, B, C, F was measured. As for the anode samples D and E, the actual specific surface area per anode of the anode sample was the same as that of the anode sample C.
The actual specific surface area of the anode sample A was 91 m ² / m ² . The positive real emergency area of the anode sample B was 125 m ² / m ² . The actual specific surface area of the anode sample C was 3700 m ² / m ² . Actual specific surface area of the anode sample F was a 11100m ² / ^{m 2.}

((Specific surface area and pore volume of first and second pores of catalyst layer of anode))
The specific surface area of the first pore, in which the pore diameter of the catalyst layer of the anode is in the range of ^{2 to 5} nm, is 10 ⁻⁵ m ² / g or less for anode samples A and B, and 1.5 m for anode samples C, D and E It was 4.5 m ² / g for ² / g and anode sample F.
The pore volume of the first pore is 10 ⁻⁶ ml / g or less for anode samples A and B, 4 × 10 ⁻⁴ ml / g for anode samples C, D and E, 5 × 10 ⁻⁵ for anode sample F It was ml / g.
The specific surface area of the second pore in which the pore diameter of the catalyst layer of the anode is in the range of 0.01 to 2.00 nm is 0.1 m ² / g or less for the anode samples A and B, and for the anode samples C, D, and E 2.5 m ² / g, was 10.5 m ² / g at the anode sample F.
The pore volume of the second pore was 0.1 ml / g or less for anode samples A and B, 0.1 ml / g for anode samples C, D and E, and 0.45 ml / g for anode sample F.

((The thickness and appearance of the anode catalyst layer))
The thickness of the catalyst layer of the anode was 10 μm or less for anode samples A and B, 200 μm for anode samples C, D and E, and 1000 μm for anode sample F.
The catalyst layer of the anode contained metal crystals of nickel.

-Cathode-
An active cathode (Pt-based thermal decomposition active cathode) in the form of a micro mesh (wire diameter: 0.1 mm, 50 mesh) was cut to a size of 50 cm square to prepare a cathode.

-Charge holder (structure)-
Blasting was performed using expanded nickel as a conductive substrate. The conductive substrate was adjusted to 50 cm square by cutting. Immersed in 5 N HCl aqueous solution for 10 minutes. The Raney nickel alloy was coated by dispersion plating and immersed in a 32 wt% aqueous NaOH solution at 80 ° C. for 10 hours to dissolve Al in the Raney nickel alloy. Through the above steps, a structure which functions as an active material is obtained.

The cathode was adjusted to be 50 cm long × 50 cm long, and was used as a cathode sample G.
The structure was adjusted to be 50 cm long × 5.73 cm wide, and was superimposed on the cathode sample G to obtain a cathode sample A.
The structure was adjusted to be 50 cm long × 0.73 cm wide, and was superimposed on the cathode sample G to obtain a cathode sample B.
The structure was adjusted to be 50 cm long × 11.98 cm wide, and was superimposed on the cathode sample G to obtain a cathode sample C.
The structure was adjusted to be 50 cm long × 18.86 cm wide, and was superimposed on the cathode sample G to obtain a cathode sample D.
The structure was adjusted to 50 cm long × 50 cm wide, and a stack of three sheets was stacked on the cathode sample G to obtain a cathode sample E.
The structure was adjusted to 50 cm long × 50 cm wide, and a stack of four sheets was superimposed on the cathode sample G to obtain a cathode sample F.

(Electric capacity of anode and cathode)
The electric capacity (C / m ² ) of the anode and the cathode of the electrolysis cell was measured as follows.

((Measurement of oxidation curve of cathode sample))
Cathode samples A, B, C, D, E, F, and G were prepared one by one, and immersed in a fluororesin beaker filled with an electrolyte solution of 30 wt% KOH. The temperature of the aqueous solution of KOH was maintained at 90.degree. A cathode sample, platinum wire mesh (counter electrode) and a tube of fluorocarbon resin covering the periphery of the counter electrode, in a device in which the electrical conductivity is ensured, reduction of the current density of 0.4 A / cm ² to the cathode sample An electric current was applied to generate hydrogen for 30 minutes. Thereafter, an oxidation current of 0.05 A / cm ² was applied to measure a change in potential of the cathode sample. This potential change was plotted against the total charge of the applied current to obtain an oxidation curve of the cathode sample.

  The measurement was performed at a temperature of 90 ° C., using a mesh-like platinum electrode as a counter electrode. As the fluorocarbon resin cylinder, one having a large number of holes of 1 mm in diameter was used. The cathode (hydrogen electrode) potential of the cathode sample was measured by a three-electrode method using a Lugin tube in order to eliminate the influence of the ohmic loss due to the liquid resistance. The distance between the tip of the Luggin tube and the cathode sample was always fixed at 0.05 mm. Silver-silver chloride (Ag / AgCl) was used as a reference electrode for the three-electrode method.

((Measurement of the amount of negative charge (electric capacity) stored in the cathode chamber when hydrogen is generated))
In the oxidation curves of the cathode samples A, B, C, D, E, F, G, in the oxidation curve of the cathode sample, the total of the currents flowed until the cathode potential became −0.8 V (vs Ag / AgCl) The amount of charge was taken as the amount of negative charge (electric capacity) stored in the cathode chamber at the time of hydrogen generation.

The negative charge amount (electric capacity) of the cathode sample A was 48250 C / m ² . The negative charge amount (electric capacity) of the cathode sample B was 9650 C / m ² . The negative charge amount (electric capacity) of the cathode sample C was 96500 C / m ² . The negative charge amount (capacitance) of the cathode sample D was 149575 C / m ² . The negative charge amount (capacitance) of the cathode sample E was 868,500 C / m ² . The negative charge amount (electric capacity) of the cathode sample F was 1158000 C / m ² . The negative charge amount (electric capacity) of the cathode sample G was 3956.5 C / m ² .

  The electrolytic cell used in the present embodiment is an electrolytic cell comprising a cathode chamber having a cathode, an anode chamber having an anode, a diaphragm which divides the cathode chamber from the anode chamber, and an electrolytic solution filled in the cathode chamber and the anode chamber. Provided. The electrolysis cell was provided with a cathode chamber having a cathode, an anode chamber having an anode, and a diaphragm that separates the cathode chamber and the anode chamber. The cathode chamber and the anode chamber were disposed to face each other via the diaphragm. The cathode chamber and the anode chamber were each filled with an electrolyte. The cathode, the anode, the diaphragm, and the electrolyte were respectively made of known materials used in the electrolysis of water.

-Diaphragm-
The polysulfone-based porous membrane was cut to 50 cm square to obtain a diaphragm sample.

-Bipolar electrolysis cell, Bipolar element-
Using 49 bipolar elements, as shown in Fig. 1, fast head, insulating plate, anode terminal unit are arranged at one end side, anode side gasket part, diaphragm, cathode side gasket part, 49 sets of arranged bipolar electrodes in this order were arranged, and further, an anode side gasket part, a diaphragm, and an electrocathode side gasket part were arranged, and a bipolar electrolytic cell was assembled.
In this embodiment, the cathode chamber and the anode chamber had 50 pairs of series connected structures each having 50 chambers.

-Gasket-
As a gasket, one made of EPDM rubber was used.

-Header, conduit-
An external header type of bipolar element was adopted.
As shown in FIG. 4, in the bipolar electrolyzer 50 of this embodiment, a conduit 20 (a liquid distribution pipe 20 Oai for anode liquid distribution and liquid collection outside the housing of the electrolyzer 50). , A cathode liquid distribution pipe 20Oci, an anode liquid collection pipe 20Oao, a cathode liquid collection pipe 20Oco). Further, in the electrolytic cell 50, hoses (anode inlet header 10Oai, a cathode inlet header 10Oci, an anode outlet header 10Oao, a cathode outlet header 10Oco) as headers 10 for passing electrolyte from the conduit 20 to the electrode chamber 5; Attached from the outside.
Here, as shown in FIG. 4, all of the headers 10 (anode inlet header 10 Oai, cathode inlet header 10 Oci, anode outlet header 10 Oao, cathode outlet header 10 Oco) are from the side of the partition wall 1 of the bipolar element 60. It was arranged to extend outward. Further, as shown in FIG. 4, all of the conduits 20 (a distribution pipe 20 Oai for the anode, a distribution pipe 20 Oci for the cathode, a collection pipe 20 Oao for the anode, a collection pipe 20Oco for the cathode) are bipolar elements 60. It was arranged to extend in the direction perpendicular to the bulkhead 1 of the
Thus, an electrolytic cell 50 of the outer header 100 was produced.
An electrolyte was allowed to flow from the cathode chamber 5c to the cathode chamber 5c via the cathode inlet header 10Oci, and from the cathode chamber 5c via the cathode outlet header 100o. In addition, an electrolytic solution was allowed to flow from the anode chamber 5a to the anode chamber 5a through the anode inlet header 10Oai, and from the anode chamber 5a through the anode outlet header 100o.
As shown in FIG. 4, the inlet hose is on one end side of the lower side of the rectangular outer frame 3 in plan view, and the outlet hose is on the upper side of the side connected to the other end of the lower side of the rectangular outer frame 3 in plan view , Each connected. Here, the inlet hose and the outlet hose are provided to face each other across the central portion of the electrode chamber 5 in the rectangular electrode chamber 5 in a plan view. The electrolyte flowed from the bottom to the top while being inclined with respect to the vertical direction, and rose along the electrode surface.
In the bipolar electrolytic cell 50 of this embodiment, the electrolyte flows from the inlet hoses of the anode chamber 5a and the cathode chamber 5c into the anode chamber 5a and the cathode chamber 5c, and the outlet hose of the anode chamber 5a and the cathode chamber 5c The electrolytic solution and the product gas flow out of the electrolytic cell 50.
In the cathode chamber 5c, hydrogen gas is generated by electrolysis, and in the anode chamber 5a, oxygen gas is generated by electrolysis. Therefore, in the cathode outlet header 10Oco described above, a mixed phase flow of electrolyte solution and hydrogen gas is generated. At 10 Oao, it became a mixed phase flow of the electrolyte and oxygen gas.

Example 1
The bipolar electrolyzer of Example 1 was produced by the following procedure.

  A cathode sample A was attached to the cathode surface of the bipolar frame, and an anode sample C was attached to the anode surface of the frame of the bipolar element to give a bipolar element. Moreover, what attached cathode sample A to the flame | frame of a cathode terminal element was made into the cathode terminal element. The anode sample C attached to the frame of the anode terminal element was used as the anode terminal element.

The area S1 of the electrodes (anode and cathode) attached to the bipolar element was adjusted to 0.25 m ² .
The cross-sectional area S2 of the flow path of the header (anode inlet header, anode outlet header, cathode inlet header, cathode outlet header) provided on the side of the outer frame was adjusted to 2.83 × 10 ⁻⁵ m ² .
The length L2 of the flow path of the header was adjusted to 0.5 m ² .

  The thickness d of the bipolar element was adjusted to 33 mm. In addition, the thicknesses of the cathode terminal element and the anode terminal element were adjusted to 0.0125 m.

  49 pieces of the above-mentioned bipolar elements were prepared. Also, one each of the cathode terminal element and the anode terminal element were prepared.

  Gaskets were applied to the metal frame portions of all the bipolar elements, the cathode terminal element and the anode terminal electrolytic cell element.

  One membrane sample was sandwiched between the anode terminal element and the cathode side of the bipolar element. The 49 bipolar elements are arranged in series so that the anode side of one of the adjacent bipolar elements is opposite to the cathode side of the other, and 48 sheets between the adjacent bipolar elements are arranged. The diaphragm samples of 1 were inserted one by one. Further, one diaphragm sample was sandwiched between the anode side of the 49th bipolar element and the cathode terminal element. These were used as a fast head, an insulating plate, and a loose head, and then tightened with a press to obtain a bipolar electrolyzer of Example 1.

A 30% KOH aqueous solution was used as an electrolytic solution.
The electrolyte circulation pump circulates the anode chamber, the oxygen separation tank (gas-liquid separation tank for the anode), the anode chamber, and the cathode chamber, the hydrogen separation tank (gas-liquid separation tank for the cathode), the cathode chamber, went.
The temperature of the electrolyte was adjusted to 90.degree.

A current was applied from the rectifier to the bipolar electrolyzer so that the area S1 of each cathode and anode was 6 kA / m ² . In Example 1, since the area S1 of the electrode is 500 mm × 500 mm, 1.5 kA was supplied from the rectifier to the bipolar electrolyzer.

  The pressure in the electrolytic cell was measured with a pressure gauge, and electrolysis was performed while adjusting the pressure on the cathode side to be 50 kPa and the pressure on the oxygen side to be 49 kPa. Pressure adjustment was performed by the pressure control valve installed downstream of the pressure gauge.

  And the alkaline water electrolysis in Example 1 was evaluated as follows.

(Electrolysis test)
Water was continuously supplied for 8 hours at a current density of 6 kA / m ² to conduct water electrolysis. The cell voltage V of the electrolytic cell was measured, and the arithmetic mean value (V) of the electrolytic cell was calculated.

(Potential holding time)
After continuously energizing for 7 hours at a current density of 6 kA / m ² , the rectifier was turned off and the cell voltage V was continuously measured. The time during which the arithmetic mean of the cell voltage V is held at 1 V or higher was taken as the potential holding time T (time) based on the time immediately after the electrolysis stop.

(Manufacturability)
The following evaluation criteria evaluated the producibility of an electrolytic cell. The results are shown in Table 1.
<Evaluation criteria>
○ (excellent): The number of welding points required to fix the electrode to the electrolytic cell is less than 500 points / m ²良 (Good): The number of welding points necessary to fix the electrode to the electrolytic cell is 500 points / m ² or more Less than 1500 points / m ² × (Defective): The number of welding points required to fix the electrode to the electrolytic bath is 1500 points / m ² or more

(Example 2)
A bipolar electrolyzer and an electrolyzer for alkaline water electrolysis were produced in the same manner as in Example 1 except that L2 was adjusted to 1 m. Detailed conditions and results are as shown in Table 1.

(Example 3)
A cathode sample was used as a cathode sample B, S1 was adjusted to 2.7 m ² , and L ² was adjusted to 2.4 m in the same manner as in Example 1 to prepare a bipolar electrolytic cell and an electrolytic apparatus for alkaline water electrolysis. Detailed conditions and results are as shown in Table 1.

(Example 4)
A bipolar electrolytic cell and an electrolytic apparatus for alkaline water electrolysis were produced in the same manner as in Example 1 except that S1 was adjusted to 2.7 m ² and L ² was adjusted to 2.4 m. Detailed conditions and results are as shown in Table 1.

(Example 5)
A bipolar electrolytic cell and an electrolytic apparatus for alkaline water electrolysis were produced in the same manner as in Example 1 except that S1 was adjusted to 2.7 m ² and L ² was adjusted to 6.5 m. Detailed conditions and results are as shown in Table 1.

(Example 6)
A bipolar electrolytic cell and an electrolytic apparatus for alkaline water electrolysis were produced in the same manner as in Example 1 except that L2 was adjusted to 0.2 m. Detailed conditions and results are as shown in Table 1.

(Example 7)
A bipolar electrolytic cell and an electrolytic apparatus for alkaline water electrolysis were produced in the same manner as in Example 1 except that the cathode sample E was used as a cathode sample. Detailed conditions and results are as shown in Table 1.

(Example 8)
A bipolar electrolytic cell and an electrolytic apparatus for alkaline water electrolysis were produced in the same manner as in Example 1 except that S1 was adjusted to 2.7 m ² and L ² was adjusted to 7.2 m. Detailed conditions and results are as shown in Table 1.

(Example 9)
A bipolar electrolyzer and an electrolyzer for alkaline water electrolysis were produced in the same manner as in Example 1 except that S2 was adjusted to 7.85 × 10 ⁻⁷ m ² and L ² was adjusted to 2.4 m. Detailed conditions and results are as shown in Table 1.

(Example 10)
A bipolar electrode type electrolytic cell and an electrolytic apparatus for alkaline water electrolysis were produced in the same manner as in Example 1 except that the cathode sample was Cathode Sample C, and S2 was adjusted to 7.85 × 10 ⁻⁷ m ² . Detailed conditions and results are as shown in Table 1.

(Example 11)
A positive electrode sample was used as a positive electrode sample B, S2 was adjusted to 1.77 × 10 ⁻⁶ m ² , L2 was adjusted to 1 m, and the bipolar electrolytic cell and the electrolytic apparatus for alkaline water electrolysis were the same as in Example 1. Made. Detailed conditions and results are as shown in Table 1.

(Example 12)
An anode sample was used as an anode sample D, a cathode sample was used as a cathode sample D, and a bipolar electrolyzer and an electrolytic apparatus for alkaline water electrolysis were produced in the same manner as in Example 1 except that L2 was adjusted to 1 m. Detailed conditions and results are as shown in Table 1.

(Example 13)
A bipolar electrolytic cell and an electrolytic apparatus for alkaline water electrolysis were produced in the same manner as in Example 1 except that L2 was adjusted to 1 m and the number of stacks was changed to 100. Detailed conditions and results are as shown in Table 1.

(Example 14)
A bipolar electrolyzer and an electrolyzer were produced in the same manner as in Example 1 except that the anode sample was an anode sample F. Detailed conditions and results are as shown in Table 1.

(Comparative example 1)
A bipolar electrolytic cell and an electrolytic apparatus for alkaline water electrolysis were produced in the same manner as in Example 1 except that the cathode sample F was used as a cathode sample. Detailed conditions and results are as shown in Table 1.

(Comparative example 2)
A bipolar electrolytic cell and an electrolytic apparatus for alkaline water electrolysis were produced in the same manner as in Example 1 except that the cathode sample was a cathode sample G. Detailed conditions and results are as shown in Table 1.

(Comparative example 3)
A bipolar electrolytic cell and an electrolytic apparatus for alkaline water electrolysis were produced in the same manner as in Example 1 except that the anode sample was an anode sample A and the cathode structure sample was a cathode sample C. Detailed conditions and results are as shown in Table 1.

(Comparative example 4)
A cathode sample was used as a cathode sample G, S1 was adjusted to 2.7 m ² , and L2 was adjusted to 2.4 m, in the same manner as in Example 1 to prepare a bipolar electrolytic cell and an electrolytic apparatus for alkaline water electrolysis. Detailed conditions and results are as shown in Table 1.

(Comparative example 5)
A bipolar electrolytic cell and an electrolytic apparatus were produced in the same manner as in Example 1 except that the anode sample was Anode sample E. Detailed conditions and results are as shown in Table 1.

In Examples 1 to 14, electrolysis was possible at 1.85 V or less, and the potential holding time was 3 hours or more, which was a sufficiently stable result for system control. Further, in Examples 1 to 13 in which the actual electrode surface area of the anode was 10000 m ² / m ² or less, the cell voltage could be further lowered. In particular, the electrolytic cells of Examples 2, 4 and 7 are excellent.
On the other hand, in Comparative Examples 1, 3 and 5, the electrolytic efficiency is poor, and in Comparative Examples 2 to 4, the potential holding time is short, and it is possible to use a fluctuating power source such as renewable energy such as wind power and sunlight. In operation, it has been shown that there are practical problems in using the electrolytic cell as an emergency storage battery at the time of stopping the power supply and operating the electric control system stably even in an emergency.

  According to the present invention, long-term storage and long-distance transport of large power can be enabled during operation with a fluctuating power source such as renewable energy, and the electric control system can be stabilized when the power supply is stopped.

Reference Signs List 1 partition 2 electrode 2a anode 2c cathode 2e conductive elastic body 2r current collector 3 outer frame 4 diaphragm 5 electrode chamber 5a anode chamber 5c cathode chamber 5i electrolyte inlet 5o electrolyte outlet 5ai anode electrolyte inlet 5ao anode electrolyte outlet 5ci Cathodic electrolyte inlet 5co Cathodic electrolyte outlet 6 Current plate 6a Anode current plate (anode rib)
6c Cathode current plate (cathode rib)
7 gasket 10 header 10I inner header 10 O outer header 10 Oai anode inlet header (anode inlet side hose)
10Oao anode outlet header (anode outlet side hose)
10Oci cathode inlet header (cathode inlet side hose)
10Oco cathode outlet header (cathode outlet side hose)
Reference Signs List 20 conduit 20 Oai anode liquid distribution pipe 20 Oao anode liquid collection pipe 20 Oci liquid distribution pipe 20Oco cathode liquid collection pipe 50 bipolar electrolytic cell 51 g fast head, loose head 51 a anode terminal element 51 c cathode terminal element 51 i insulating plate 51 r Tie rod 60 Bipolar element 65 Electrolytic cell 70 Electrolyzer 71 Electrolyte circulation pump 72 Gas-liquid separation tank 72h Hydrogen separation tank 72o Oxygen separation tank 73 Water input pump 74 Rectifier 75 Oxygen meter 76 Hydrogen concentration meter 77 Flow meter 78 Pressure meter 79 Heat exchanger 80 Pressure control valve D1 Given direction along the partition (direction of electrolyte passage)
S1 area of conducting surface of bipolar element Cross section of flow path of S2 header Flow path length of L header Z Zero gap structure d Thickness of electrolytic cell

Claims (24)

A plurality of bipolar elements including an anode, a cathode, a partition separating the anode and the cathode, and an outer frame bordering the partition are superimposed with a diaphragm interposed therebetween, A bipolar electrolyzer comprising: a header communicating with an electrode chamber defined by the partition wall, the outer frame, and the diaphragm;
The electric capacity of the anode is in the range of 4825 C / m ^{2 to} 965000 C / m ² , and the electric capacity of the cathode is in the range of 4825 C / m ^{2 to} 965000 C / m ² .
Bipolar electrolyzer characterized in that. A plurality of bipolar elements including an anode, a cathode, a partition separating the anode and the cathode, and an outer frame bordering the partition are superimposed with a diaphragm interposed therebetween, A bipolar electrolyzer comprising: a header communicating with an electrode chamber defined by the partition wall, the outer frame, and the diaphragm;
The electric capacity of the anode is in the range of 4825 C / m ^{2 to} 965000 C / m ² , and the electric capacity of the cathode is in the range of 4825 C / m ^{2 to} 965000 C / m ² .
A bipolar electrolyzer for alkaline water electrolysis, characterized in that Assuming that the area of the current-carrying surface of the bipolar element is S1, the cross-sectional area of the flow path of the header is S2, and the length of the flow path of the header is L2, (S2 / S1) / L2 is 1.5. The bipolar electrolyzer according to claim 1 or 2, which has a range of ^10-6 m- ^{1 to} 2.3 ^10-4 m- ¹ . Range lower of 9650C ^{/ m 2} ~955350C ^/ m 2 of the electric capacity and electric capacity of the cathode of the anode, a bipolar type electrolytic cell according to any one of claims 1 to 3.   The bipolar electrolytic cell according to any one of claims 1 to 4, wherein an electric capacity of the anode is larger than an electric capacity of the cathode.   The bipolar electrolytic cell according to claim 5, wherein the electric capacity of the cathode is more than 0.1 times and not more than 0.99 times the electric capacity of the anode.   The bipolar electrolytic cell according to claim 5 or 6, wherein the electric capacity of the cathode is more than 0.1 times and 0.49 times or less of the electric capacity of the anode. Real electrode surface area of the geometric cell area 1 m ² per the anode ^is in the range of 90m ² ~10000m 2, a bipolar type electrolytic cell according to any one of claims 1 to 7.   The bipolar electrolyzer according to any one of the preceding claims, having 50 to 500 bipolar elements. Wherein S1 is a 0.1 m ² through 10m ^2, a bipolar type electrolytic cell according to any one of claims 2-9.   The bipolar electrolyzer according to any one of claims 2 to 10, wherein the thickness d of the electrolysis cell is 10 mm to 100 mm.   The bipolar electrolytic cell according to any one of claims 1 to 11, wherein the anode contains at least one nickel compound selected from the group consisting of nickel oxide, metallic nickel, nickel hydroxide and a nickel alloy. The anode comprises a conductive substrate and a catalyst layer disposed on the conductive substrate,
The catalyst layer contains metal crystals of nickel and has pores.
Of the pores of the catalyst layer,
The specific surface area of the first pore whose pore diameter is in the range of ² to 5 nm is 0.6 to 2.0 m ² / g,
The pore volume of the first pore is 3 × 10 ^{−4 to} 9 × 10 ⁻⁴ ml / g,
Among the pores, the specific surface area of the second pores having a pore diameter in the range of 0.01 to 2.00 μm is 2.0 to 5.0 m ² / g,
The pore volume of the second pore is 0.04 to 0.2 ml / g,
The thickness of the catalyst layer is 50 to 800 μm,
The bipolar electrolytic cell according to any one of claims 1 to 12.   At least one Pt group selected from the group consisting of Ru-La-Pt system, Ru-Ce system, Pt-Ce system, and Pt-Ir system, Ir-Pt-Pd system, Pt-Ni system. The bipolar electrolyzer according to any one of claims 1 to 13, comprising a compound.   The configuration of the cathode and the anode has a catalyst layer on the surface of the conductive substrate, and the conductive substrate is at least selected from the group consisting of metallic nickel, nickel oxide, nickel hydroxide and a nickel alloy. The bipolar electrolyzer according to claim 14, which comprises one kind of nickel compound.   The bipolar electrolytic cell according to any one of claims 1 to 15, wherein the cathode and the anode have a mesh-like structure.   The compound according to any one of claims 1 to 16, wherein the base material of the cathode has a wire diameter in the range of 0.05 mm to 0.5 mm, and the opening has a range of 30 mesh to 80 mesh. Polar electrolytic cell.   The substrate of the said anode is a mesh-like structure which has an aperture ratio in the range of 20%-60%, The bipolar electrolysis cell as described in any one of Claims 1-17.   19. The bipolar electrolyzer according to claim 1, wherein the electrolysis cells are electrically connected in series.   The cathode, the anode, the diaphragm, and a bipolar element having a partition that defines the anode chamber and the cathode chamber, wherein the diaphragm is positioned between the cathode and the anode, and the diaphragm is in contact with the cathode and the anode 20. The bipolar water electrolytic cell according to claim 19, wherein   A bipolar electrolytic cell according to any one of claims 1 to 20, an electrolytic solution circulation pump for circulating the electrolytic solution, a gas-liquid separation tank for separating the electrolytic solution and hydrogen and / or oxygen An electrolyzer, comprising: a water input pump for supplying water.   22. The electrolytic device according to claim 21, further comprising: a detector that detects a stop of the power supply when the supply of power to the electrolytic device is stopped, and a controller that automatically shuts off the electrolyte circulation pump.   The water electrolysis method characterized by stopping the said electrolyte solution circulation pump at the time of the stop of the electric power supply to the electrolysis apparatus of Claim 21 or 22. In a hydrogen production method of producing hydrogen by electrolyzing water containing an alkali with an electrolytic cell,
In the electrolytic cell, a plurality of bipolar elements including an anode, a cathode, a partition separating the anode and the cathode, and an outer frame bordering the partition are stacked with a diaphragm interposed therebetween, A bipolar electrolyzer comprising a header communicating with an electrode chamber defined by the partition wall, the outer frame and the diaphragm outside the frame, wherein the electric capacity of the anode is 4825 C / m ^{2 to} 965000 C. / ^m is in the range of ^2, wherein the electric capacity of the cathode is in the range of ^{4825C / m 2 ~965000C / m 2} , a hydrogen production method.

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