JP6803406B2 - Electrolytic cell, electrolyzer, electrolysis method - Google Patents

Description

The present invention relates to a multi-pole electrolytic cell, an electrolyzer, and a water electrolysis method.

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

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

Therefore, research is being conducted to replace the electric power generated from renewable energy with a form that can be stored and transported. Specifically, it has been 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 a 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. The sex is also expanding. Therefore, there are high expectations for the development of technology for obtaining hydrogen of particularly high purity from renewable energy.

Examples of the method for electrolyzing water include a polymer electrolyte water electrolysis method, a high temperature steam electrolysis method, and an alkaline water electrolysis method. Among them, alkaline water electrolysis is one of the most promising ones because it has been industrialized for more than several decades, it can be carried out on a large scale, and it is cheaper than other water electrolyzers. Has been done.

However, in order to adapt alkaline water electrolysis as a means for storing and transporting energy in the future, as described above, it is possible to efficiently and stably use electric power with large fluctuations in output to perform water electrolysis. There is a need to. Therefore, it is required to solve various problems of electrolytic cells and devices for alkaline water electrolysis.

In order to solve the problem of improving the electric power intensity of hydrogen production by keeping the electrolytic voltage low in alkaline water electrolysis, the structure of the electrolytic 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 through the pores of the electrode to the side opposite to the diaphragm side of the electrode, thereby reducing the distance between the electrodes and suppressing the generation of gas pools in the vicinity of the electrodes as much as possible for electrolysis. The voltage is suppressed low. The zero gap structure is extremely effective in suppressing the electrolytic voltage, and is used in various electrolytic devices.

On the other hand, it has also been reported by Detref Stonen et al. That it is important to optimally select electrodes and diaphragms and optimize the structure of electrolytic cells in order to realize efficient and stable alkaline water electrolysis (). See Non-Patent Document 1). Further, in recent years, studies on an electrolytic cell for alkaline water electrolysis having a zero gap structure have been actively conducted to tackle the above-mentioned problems (see Patent Documents 3 and 4).

U.S. Pat. No. 4,530,743 Japanese Unexamined Patent Publication No. 59-173281 International Publication No. 2013/191140 International Publication No. 2014/178317

Detlef Stonen, "Hydrogen Energy", Germany, Wiley-VCH Verlag GmbH & Co., Ltd. KGaA, 2010, pp. 254-257

However, as a multi-pole electrolytic tank, those having various structures have been developed so far, but in order to operate stably when a fluctuating electric power such as renewable energy is input to such an electrolytic tank. It is necessary to control a complicated electric drive control system, but since the electric drive control system cannot be controlled in the event of a sudden power supply stop, improvement is required.

Therefore, an object of the present invention is to enable highly efficient hydrogen production when operating with a variable power source such as renewable energy, and further to stabilize an electric control system when the power supply is stopped. ..

The gist of the present invention is as follows.
In the bipolar electrolytic cell of the present invention, a plurality of bipolar elements including an anode, a cathode, a partition wall that separates the anode and the cathode, and an outer frame that borders the partition wall are stacked with a diaphragm in between. A multi-pole electrolytic cell that is combined and has a header communicating with an electrode chamber defined by the partition wall, the outer frame, and the diaphragm on the outside of the outer frame.
The capacitance of the anode is in a range of ^{4825C / m 2 ~965000C / m 2} , the capacitance of the cathode Ri range der of ^{4825C / m 2 ~965000C / m 2} ,
When the area of the energizing surface of the multi-pole 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 1.31. It is in the range of × 10 ^-6 m ^{-1 to} 2.3 × 10 ^-4 m ^-1 .
It is characterized by that.
Here, the bipolar electrolytic cell of the present invention is preferably a bipolar electrolytic cell for alkaline water electrolysis.
Et al is, the bipolar type electrolytic cell of the present invention is preferably lower of the electric capacity and electric capacity of the cathode of the anode is in the range of ^{9650C / m 2 ~955350C / m 2} .
Further, in the multi-pole electrolytic cell of the present invention, it is preferable that the electric capacity of the anode is larger than the electric capacity of the cathode.
Further, in the multi-pole electrolytic cell of the present invention, the electric capacity of the cathode is preferably more than 0.1 times the electric capacity of the anode and 0.99 times or less.
Further, in the multi-pole 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.
Further, the multi-pole electrolytic cell of the present invention preferably has 50 to 500 multi-pole 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.
Further, in the multi-pole electrolytic cell of the present invention, the thickness d of the electrolytic cell is preferably 10 mm to 100 mm.
Further, in the bipolar electrolytic cell of the present invention, it is preferable that the anode contains at least one nickel compound selected from the group consisting of nickel oxide, metallic nickel, nickel hydroxide and nickel alloys.
Further, in the multipolar electrolytic cell of the present invention, the anode has a conductive base material and a catalyst layer arranged on the conductive base material, and the catalyst layer contains a metal crystal of nickel. Moreover, among the pores of the catalyst layer having pores, the specific surface area of the first pores having a pore diameter in the range of ² to 5 nm is 0.6 to 2.0 m ² / g. The pore volume of one pore is 3 × 10 ^{-4 to} 9 × 10 ^-4 ml / g, and the pore diameter of the second pore 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 preferable.
Further, in the multipolar electrolytic cell of the present invention, the cathode is Ru-La-Pt system, Ru-Ce system, Pt-Ce system, and Pt-Ir system, Ir-Pt-Pd system, Pt-Ni system. It is preferable to contain at least one Pt group compound selected from the group consisting of.
Further, in the multi-pole electrolytic cell of the present invention, the structure of the cathode and the anode has a catalyst layer on the surface of the conductive base material, and the conductive base material is metallic nickel, nickel oxide, or hydroxide. It preferably contains at least one nickel compound selected from the group consisting of nickel and nickel alloys.
Further, in the multi-pole electrolytic cell of the present invention, it is preferable that the cathode and the anode have a mesh-like structure.
Further, in the multi-pole electrolytic cell of the present invention, it is preferable that 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. ..
Further, the bipolar electrolytic cell of the present invention preferably has a mesh-like structure in which the base material of the anode has an aperture ratio in the range of 20% to 60%.
Further, the multi-pole electrolytic cell of the present invention preferably has electrolytic cells electrically connected in series.
Further, the bipolar electrolytic cell of the present invention includes a bipolar element having the cathode, the anode, the diaphragm, and a partition wall separating the anode chamber and the cathode chamber, and the anode is located between the cathode and the anode. However, it is preferable that the diaphragm is in contact with the cathode and the anode.

The electrolyzer of the present invention uses the multi-pole 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 from hydrogen and / or oxygen, and water. It is characterized by including a water injection pump for replenishment.
Further, 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 electrolytic solution circulation pump. preferable.

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

The hydrogen production method of the present invention is a hydrogen production method in which water containing an alkali is electrolyzed by an electrolytic cell to produce hydrogen, in which the electrolytic cell separates an anode and a cathode, and the anode and the cathode. A plurality of bipolar elements including a partition wall and an outer frame that borders the partition wall are overlapped with each other sandwiching a diaphragm, and are defined by the partition wall, the outer frame, and the diaphragm on the outer side of the outer frame. It is a multi-pole electrolytic cell provided with a header communicating with the electrode chamber, 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. / range der of m ² is, the Fukukyokushiki S1 is the area of the energizing surface of the element, the flow path cross-sectional area of S2 of the header, the length of the flow path of the header when the L2, (S2 / S1) / L2 is characterized scope der Rukoto of ^{1.31 × 10 -6 m -1 ~2.3 ×} 10 -4 m -1.

According to the present invention, it is possible to produce hydrogen with high efficiency when operating with a variable power source such as renewable energy, and further to stabilize the electric control system when the power supply is stopped.

It is a side view which shows the whole example of the multi-pole type electrolytic cell for alkaline water electrolysis of this embodiment. It is a perspective view which shows the electrolytic cell, the header, and the conduit of an example of the bipolar electrolysis tank for alkaline water electrolysis of this embodiment. It is a perspective view which shows the flow of the electrolytic solution in an example of the bipolar type electrolytic cell for alkaline water electrolysis of this embodiment. It is a top view which shows the example of the external header type multi-pole type electrolytic cell for alkaline water electrolysis of this embodiment. It is a figure which shows the outline of the electrolytic apparatus for alkaline water electrolysis of this embodiment.

Hereinafter, embodiments 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 gist thereof.

FIG. 1 shows a side view of an entire example of a multi-pole electrolytic cell for alkaline water electrolysis according to the present embodiment.
FIG. 2 shows a perspective view of an electrolytic cell, a header, and a conduit of an example of a multi-polar electrolytic cell for alkaline water electrolysis of the present embodiment.
FIG. 3 shows a perspective view of the flow of the electrolytic solution in an example of the multi-pole electrolytic cell for alkaline water electrolysis of the present embodiment.
As shown in FIG. 1, the multi-pole electrolytic cell 50 for alkaline water electrolysis of the present embodiment has an anode 2a, a cathode 2c, a partition wall 1 that separates the anode 2a and the cathode 2c, and an outer frame that borders the partition wall 1. A multi-pole electrolytic cell 50 in which a plurality of multi-pole elements 60 including 3 are superposed with a diaphragm 4 interposed therebetween.

(Multi-pole electrolytic cell)
The multi-pole type is one of the methods for connecting a large number of cells to a power source. A plurality of multi-pole elements 60 having an anode 2a on one side and a cathode 2c on one side are arranged in the same direction and connected in series, and only both ends are connected. Is a way to connect to the power supply.
The multi-pole electrolytic cell 50 has a feature that the current of the power source can be reduced, and a large amount of a compound, a predetermined substance, or the like can be produced in a short time by electrolysis. As long as the output of the power supply equipment is the same, constant current and high voltage are cheaper and more compact, so industrially, the multi-pole type is preferable to the single-pole type.

((Multipolar element))
As shown in FIG. 1, the bipolar element 60 used in the double-pole electrolytic cell 50 for alkaline water electrolysis is provided with a partition wall 1 that separates the anode 2a and the cathode 2c, and has an outer frame that borders the partition wall 1. It has 3. More specifically, the partition wall 1 has conductivity, and the outer frame 3 is provided so as to surround the partition wall 1 along the outer edge of the partition wall 1.

In the present embodiment, the multi-pole element 60 may be used so that the given direction D1 along the partition wall 1 is usually in the vertical direction. Specifically, FIGS. 2 and 3 show. As shown, when the plan view shape of the partition wall 1 is rectangular, the given direction D1 along the partition wall 1 is used so as to be in the same direction as the direction of one of the two sets of opposite sides. (See FIGS. 1 to 5). In the present specification, the vertical direction is also referred to as an electrolytic solution passing direction.

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

As shown in FIG. 1, in the multi-pole electrolytic cell 50, the multi-pole element 60 is arranged between the anode terminal element 51a and the cathode terminal element 51c. The diaphragm 4 is arranged between the anode terminal element 51a and the dipole element 60, between the bipolar elements 60 arranged adjacent to each other, and between the dipole element 60 and the cathode terminal element 51c. ..

Further, in the multi-pole electrolytic cell 50 of the present embodiment, as shown in FIGS. 2 and 3, an electrode chamber 5 through which the electrolytic solution passes is defined by the partition wall 1, the outer frame 3, and the diaphragm 4.

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

Specifically, the electrode chamber 5 has an electrolytic solution inlet 5i for introducing the electrolytic solution into the electrode chamber 5 and an electrolytic solution outlet 5o for drawing out the electrolytic solution 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 electrolytic solution into the anode chamber 5a and an anode electrolyte outlet 5ao for leading out the electrolytic solution to be led out from the anode chamber 5a. Similarly, the cathode chamber 5c is provided with a cathode electrolytic solution inlet 5ci for introducing the electrolytic solution into the cathode chamber 5c and a cathode electrolytic solution outlet 5co for leading out the electrolytic solution to be led out from the cathode chamber 5c.

The multi-pole electrolytic cell 50 in the present embodiment is provided with a header 10 communicating with the electrode chamber 5 on the outside of the outer frame 3 (see FIGS. 2 and 3).

In the example shown in FIGS. 2 and 3, a header 10 which is a tube for distributing or collecting a gas or an electrolytic solution is attached to the multi-pole electrolytic cell 50. Specifically, the header 10 includes an inlet header for putting the electrolytic solution into the electrode chamber 5 and an outlet header for discharging gas and the electrolytic solution from the electrode chamber 5.
In one example, below the outer frame 3 at the edge of the partition wall 1, an anode inlet header 10Oai for putting an electrolytic solution in the anode chamber 5a and a cathode inlet header 10Oci for putting the electrolytic solution in the cathode chamber 5c are provided. Similarly, an anode outlet header 10Oao for discharging the electrode solution from the anode chamber 5a and a cathode outlet header 10Oco for discharging the electrolytic solution from the cathode chamber 5c are provided on the side of the outer frame 3 on the edge of the partition wall 1. ..
Further, in one example, in the anode chamber 5a and the cathode chamber 5c, the inlet header and the outlet header are provided so as to face each other with the central portion of the electrode chamber 5 interposed therebetween.

In particular, the multi-pole electrolytic cell 50 of this example adopts an external header 10O type in which the multi-pole electrolytic cell 50 and the header 10 are independent.
FIG. 4 shows a plan view of an example of the external header type multi-pole electrolytic cell for alkaline water electrolysis of the present embodiment.

As the arrangement mode of the header 10 attached to the multi-pole electrolytic cell shown in FIGS. 1 to 3, typically, there are an internal header 10I type and an external header 10O type, but in the present invention, any of them is used. A mold may be adopted and is not particularly limited.

Further, in the example shown in FIGS. 2 and 3, the header 10 is attached with a conduit 20 which is a pipe for collecting the gas or electrolytic solution distributed or collected in the header 10. Specifically, the conduit 20 comprises a liquid distribution pipe communicating with the inlet header and a liquid collecting pipe communicating with the outlet header.
In one example, an anode liquid distribution tube 20Oai communicating with the anode inlet header 10Oai and a cathode liquid distribution tube 20Oci communicating with the cathode inlet header 10Oci are provided below the outer frame 3, and similarly. On the side of the outer frame 3, an anode liquid collecting tube 20Oao communicating with the anode outlet header 10Oao and a cathode liquid collecting tube 20Oco communicating with the cathode outlet header 10Oco are provided.

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 separate positions from the viewpoint of water electrolysis efficiency, and face each other with the central portion of the electrode chamber 5 interposed therebetween. When the plan view shape of the partition wall 1 is rectangular as shown in FIGS. 2 and 3, it is preferable that the partition wall 1 is provided so as to be symmetrical with respect to the center of the rectangle.

Normally, 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 10Oco are provided in each electrode chamber 5, but in the present embodiment, one is provided. The present invention is not limited to this, and a plurality of electrodes may be provided in each electrode chamber 5.
Further, normally, the anode liquid distribution tube 20Oai, the cathode liquid distribution tube 20Oci, the anode liquid collection tube 20Oao, and the cathode liquid collection tube 20Oco are provided one in each electrode chamber 5, but in the present embodiment, one is provided. The present invention is not limited to this, and a plurality of electrode chambers 5 may be used in combination.

In the illustrated example, the rectangular partition wall 1 in the plan view and the rectangular diaphragm 4 in the plan view are arranged in parallel, and the partition wall 1 side of the rectangular parallelepiped outer frame provided at the end edge of the partition wall 1. Since the inner surface of the electrode chamber 5 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 parallelepiped of the illustrated example, and is formed by the plan view shape of the partition wall 1 and the diaphragm 4, and the inner surface of the outer frame 3 on the partition wall 1 side and the partition wall 1. It may be appropriately deformed depending on the angle and the like, and may have any shape as long as the effect 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 FIGS. 2 and 3, from the viewpoint of facilitating the effect of the present invention, the liquid distribution pipe (the liquid distribution for the anode). The pipe 20Oai (cathode liquid distribution pipe 20Oci) and the liquid collection pipe (anode liquid collecting pipe 20Oao, cathode liquid collecting pipe 20Oco) each preferably extend in a direction perpendicular to the partition wall 1, and the conduit 20 It is more preferable that all of the above extend in the direction perpendicular to the partition wall 1.

Occasionally, the electrolytic cell 65 causes a self-discharge reaction via a leakage current circuit formed by the electrolytic solution supply pipe when the electrolysis is stopped.

A structure having an electric capacity for holding the cell voltage of the electrolytic cell 65 even when the self-discharge occurs is called a charge holder. The charge holder can be electrically connected to the cathode 2c or the anode 2a inside the cathode chamber 5c or the anode chamber 5a to stabilize the electrochemical potential of the cathode 2c or the anode 2a 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 that supports the catalyst layer, and the catalyst layer and the base material have a function of a charge holder.

Here, in the bipolar electrolysis tank 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 ). Yes, the electrical 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 ).

When operating with a variable 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, by improving the structure of the electrolyte supply pipe, By reducing the self-discharge that occurs 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 electric 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 Is most preferable. 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 alkaline water electrolysis for the bipolar type electrolytic cell 50 of the present embodiment, it is preferable that a range lower of 9650C ^{/ m 2} ~955350C ^/ m 2 of the electric capacity of the electric capacity and the cathode 2c of the anode 2a, 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 becomes difficult to function as a power source, and if the lower one of the electric capacities is too large, it becomes practically difficult to manufacture.

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, and in that case, the ratio of the electric capacity of the cathode to the electric capacity of the anode is 0. It is preferably in the range of more than 1. times and 0.99 times or less, and more preferably in the range of more than 0.1 times and 0.49 times or less.

Regarding the electrode 2 (anode 2a, cathode 2c), an electrode composite (anode composite, cathode composite) including a conductive elastic body 2e and a current collector 2r in addition to the electrode 2 (anode 2a, cathode 2c). When is used, the above-mentioned electric capacity may be determined for the electrode composite (anode composite, cathode composite).

The above-mentioned effect of the present invention is less subject to physical restrictions on the header design, and it is structurally easy to shut off the electrolytic solution discharge line (outlet header) on the electrolytic solution outlet 5o side when electrolysis is stopped. It can be easily obtained in an external header 10O type alkaline water electrolytic cell in which a header for supplying an electrolytic solution to each electrolytic cell 65 is arranged outside the electrolytic cell 65.

In the double-pole electrolytic cell 50 for alkaline water electrolysis of the present embodiment, the area of the energizing surface of the double-pole element 60 is S1, the cross-sectional area of the flow path of the header 10 is S2, and the length of the flow path of the header 10 is L2. When (S2 / S1) / L2 is preferably in the range of 1.5 × 10 ^-6 m ^{-1 to} 2.3 × 10 ^-4 m ^-1 , 4.0 × 10 ^-6 m. It is more preferably in the range of ^{-1 to} 2.0 × 10 ^-4 m ^-1 , especially in the range of 8.0 × 10 ^-6 m ^{-1 to} 1.0 × 10 ^-4 m ^-1. preferable.

The area S1 of the energizing surface of the dipole element 60 means the area of the electrodes (anode 2a and cathode 2c) of the dipole element 60 on the surface parallel to the partition wall. When the above-mentioned areas are different between the anode 2a and the cathode 2c, the average thereof is used.
The cross-sectional area S2 of the flow path of the header 10 refers to the cross-sectional area of the internal space of the header 10 through which the electrolytic solution passes. If there is a change in the cross-sectional area in the extending direction of the header 10, the average of the cross-sectional areas is used. If the cross-sectional areas of the anode inlet header 10Oai, the cathode inlet header 10Oci, the anode outlet header 10Oao, and the cathode outlet header 10Oco are different, the average thereof is used.
The length L2 of the flow path of the header 10 means the extending length of the internal space of the header 10 through which the electrolytic solution passes. In particular, when the conduit 20 communicating with the header 10 is provided, the header 10 is connected to the electrolyte inlet 5i to the connection portion with the liquid distribution pipe (conduit 20), or from the electrolyte outlet 5o to the liquid collection pipe (conduit). The length of the part up to the connection part. Further, when the above lengths are different in the anode inlet header 10Oai, the cathode inlet header 10Oci, the anode outlet header 10Oao, and the cathode outlet header 10Oco, the average thereof is used.

When (S2 / S1) / L2 is within the above range, self-discharge generated when the power supply is stopped can be reduced, the electric control system can be stabilized, and power can be stored with high efficiency. Specifically, by reducing the leakage current, it is possible to realize hydrogen production with high efficiency.

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 energizing surface is too small, the electrolytic solution supply header will also be small, making it difficult to manufacture the electrolytic cell 50. Further, if the energized surface is too large, the sealing surface pressure tends to be non-uniform, which causes leakage of the electrolytic solution and gas leakage.

Further, in the double-pole 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. It is particularly preferable to have.
The thickness d of the electrolytic cell 65 is the thickness of the portion between the partition walls 1 between the two adjacent bipolar elements 60, and the adjacent bipolar elements 60 and the terminal elements 51a and 51c. The thickness of the portion between the partition walls 1 of each other, the distance between the partition walls 1 of the two adjacent multi-pole elements 60 in the direction perpendicular to the partition wall 1, and the adjacent multi-pole type. The distance between the partition wall 1 of the element 60 and the partition walls 1 of the terminal elements 51a and 51c in the direction perpendicular to the partition wall 1. When the thickness d is not constant in the entire multi-pole electrolytic cell 50, the average thereof may be used.
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. Further, if the thickness d is too large, uniform distribution becomes difficult due to the influence of pressure loss of the header 10, and the installation area becomes too large.

Further, in the multi-pole electrolytic cell 50 for alkaline water electrolysis of the present embodiment, S2 is used from the viewpoint of further purifying the gas purity and suppressing the flow path blockage due to the solid matter existing in the circulation flow path. , 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.

Further, in the double-pole electrolytic cell 50 for alkaline water electrolysis of the present embodiment, L2 is 0.2 m to 10 m from the same viewpoint as in the case of the preferable range of S2, although it is not particularly limited. It is preferably 0.4 m to 8 m, and more preferably 0.4 m to 8 m.

The multi-pole electrolytic cell 50 for alkaline water electrolysis of the present embodiment preferably has 50 to 500 multi-pole elements 60, more preferably 70 to 300 multi-pole elements 60, and 100 to 200. It is particularly preferable to have the multi-pole element 60 of the above.
If it is less than the lower limit, the ratio of the tightening mechanism to the cell becomes relatively large, which increases the manufacturing cost and increases the installation area of the equipment, which may make the equipment unrealistic. When the upper limit is exceeded, the effect of reducing the self-discharge that occurs when the power supply is stopped and enabling the stabilization of the electric control system, and the storage of power with high efficiency, specifically, the pump It becomes difficult to arrange the effects that make it possible to reduce the power and the leakage current.
Further, if the number (logarithm) of the multi-pole elements 60 increases too much, it may be difficult to manufacture the electrolytic cell 50, and when a large number of multi-pole elements 60 having poor manufacturing accuracy are stacked, the sealing surface pressure Is likely to be non-uniform, and electrolyte leakage and gas leakage are likely to occur.

Hereinafter, the components of the multi-pole electrolytic cell 50 for alkaline water electrolysis of the present embodiment will be described in detail.
Further, in the following, a preferred embodiment for enhancing the effect of the present invention will be described in detail.

− Septum −
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 plan view shape of the partition wall 1 is not particularly limited, and may be a rectangle (square, rectangle, etc.) or a circle (circle, ellipse, etc.). Here, the rectangle may have rounded corners.
In one embodiment, the partition wall 1 and the outer frame 3 may be joined by welding or other methods to be integrated. For example, a flange portion extending from the partition wall 1 in a direction perpendicular to the plane of the partition wall 1 ( An anode flange portion overhanging on the anode 2a side and a cathode flange portion overhanging on the cathode 2c side) may be provided, and the flange portion may be a part of the outer frame 3.

The partition wall 1 may normally be used so that the given direction D1 along the partition wall 1 is in the vertical direction. Specifically, as shown in FIGS. 2 and 3, the partition wall 1 is viewed in a plan view. When the shape is rectangular, it may be used so that the given direction D1 along the partition wall 1 is in the same direction as the direction of one of the two opposing sides. In the present specification, the vertical direction is also referred to as an electrolytic solution passing direction.

As the material of the partition wall 1, a conductive material is preferable from the viewpoint of realizing a 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. Is preferable.

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

In addition to the theoretically required voltage for electrolysis of water, the electrolytic voltage of alkaline water electrolysis is the overvoltage of the anode reaction (oxygen generation), the overvoltage of the cathode reaction (hydrogen generation), and the anode 2a and the cathode 2c. It is divided into the voltage according to the distance between the electrodes 2. Here, the overvoltage means a voltage that needs to be excessively applied beyond the theoretical decomposition potential when a certain current is passed, and the value depends on the current value. When the same current is passed, power consumption can be reduced by using the electrode 2 having a low overvoltage.

In order to realize a low overvoltage, the requirements for the electrode 2 are high conductivity, high oxygen-evolving ability (or hydrogen-evolving ability), high wettability of the electrolytic solution on the surface of the electrode 2, and the like. Can be mentioned.

Even if an unstable current such as renewable energy is used as the electrode 2 for alkaline water electrolysis in addition to the low overvoltage, the base material and the catalyst layer of the electrode 2 are corroded, the catalyst layer is shed, and the electrolytic solution is subjected to. It can be mentioned that dissolution, adhesion of inclusions to the diaphragm 4 and the like are unlikely to occur.

The structure of the conductive base material of the anode and the cathode is preferably a mesh structure from the viewpoint of ensuring a specific surface area as a carrier and achieving both defoaming property. The material of the conductive base material may be at least one selected from the group consisting of nickel iron, vanadium, molybdenum, copper, silver, manganese, platinum group, graphite, chromium and the like. An alloy composed of two or more kinds of metals or a mixture of two or more kinds of conductive substances may be used as the conductive base material. It is preferable to use metallic nickel as the conductive base material.

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

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

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. When the surface of the actual electrode 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. Further, in the range where the surface of the actual electrode exceeds 10000 m ² / m ² , it is expected that the catalyst layer becomes very brittle because it contains fine porous materials, the durability is poor, and the oxygen overvoltage increases with the generation of oxygen. ..
The geometric cell area refers to the area when the electrolytic 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 pores having a pore diameter in the range of ² to 5 nm is 0.6 to 2.0 m ² / g, and the pores of the first pores. 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 having a pore diameter in the range of 0.01 to 2.00 μm is 2.0 to 5.0 m ² / g, and the second pore is fine. The pore volume is preferably 0.04 to 0.2 ml / g.
The thickness of the catalyst layer is preferably 50 to 800 μm, more preferably 100 to 400 μm.

The second pore having a pore diameter in the range of 0.01 to 2.00 μm has a small specific surface area but a large pore volume, so that the first pore exists on the inner wall of the second pore. Become. The first pores greatly increase the surface area of the catalyst layer. The surface of the first pores functions as a reaction field (reaction interface) for the oxidation reaction of hydroxide ions (oxygen generation reaction). Inside the first pores, nickel hydroxide is produced during oxygen evolution, which is expected to make the pores even smaller. However, since the first pores exist inside the second pores having a large pore diameter, oxygen generated in the first pores easily escapes to the outside of the catalyst layer through the second pores and does not easily inhibit electrolysis. .. Therefore, in this embodiment, it is presumed that the oxygen evolution overvoltage does not easily increase during 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. Generally, it is considered that the oxygen evolution potential decreases as the specific surface area of the first pore increases. However, if the first pores are too small, the first pores tend to be completely filled with nickel hydroxide generated when oxygen is generated, and the substantial surface area of the first pores tends to decrease. 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 evolution potential tends to increase.

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

The volume of the second pore 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 be easily defoamed. As the pore volume of the second pore decreases, the oxygen gas generated in the catalyst layer tends to be difficult to defoam, and the oxygen evolution 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, the catalyst layer is thin, so that the surface area of the entire catalyst layer is small, and it is expected that the oxygen overvoltage will be high. Further, in the range where the thickness exceeds 800 μm, the catalyst layer may become too thick and peeling or the like may easily occur, and the manufacturing cost of the anode may become too high.

The catalyst layer contains nickel metal crystals, the peak intensity of X-rays diffracted by the (1,1,1) planes of the nickel metal crystals in the catalyst layer is I _Ni , and the (0) of NiO in the catalyst layer. , 1, 2) When the peak intensity of X-rays diffracted by the plane is I _NiO , the value of [I _Ni / (I _Ni + I _NiO )] × 100 is preferably 75 to 100%. I [I _Ni / (I _Ni + I _NiO )] × 100 is more preferably 90 to 100%, and particularly preferably 95 to 100%.

The larger [I _Ni / (I _Ni + I _NiO )] × 100, the lower the electrical resistance of the catalyst layer and the smaller the voltage loss when oxygen is generated. In the nickel oxide portion of the catalyst layer, the conductivity is lowered, but the oxygen evolution reaction is unlikely to occur. Further, since nickel oxide is relatively excellent in chemical stability, it may be effective for the catalyst layer to contain nickel oxide in order to maintain the strength of the catalyst layer. In addition, I _Ni and I _NiO are obtained from the measurement result of XRD ((X-Ray Diffraction)) for the catalyst layer.

The catalyst layer may contain an alloy composed of nickel and other metals. 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, platinum group, rare earth elements and the like. Further, 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 method for producing the anode for alkaline water electrolysis according to the present embodiment is not particularly limited. A preferred production method includes a method in which expanded nickel is used as a base material, Raney nickel is coated by dispersion plating, and the Raney nickel is developed with 32 wt% alkali.

--Cathode ---
The cathode 2c is not particularly limited. Includes at least one Pt group compound selected from the group consisting of Ru-La-Pt series, Ru-Ce series, Pt-Ce series, and Pt-Ir series, Ir-Pt-Pd series, and Pt-Ni series. Is preferable. Further, it is preferably a pyrolysis type active cathode. The structure of the base material of the cathode is preferably a mesh structure in terms of ensuring a specific surface area as a carrier and achieving both defoaming property.

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 nickel alloys.

In particular, it is preferable that the base material of the cathode has a linearity in the range of 0.05 to 0.5 mm and the opening has a range of 30 mesh to 80 mesh. Within this range, it is possible to exhibit the specific surface area and defoaming property required as a carrier while maintaining the mechanical strength of the mesh as a cathode. By setting the aperture ratio of the mesh of the conductive base material of the anode in the range of 20% to 60%, it is possible to exhibit the specific surface area and defoaming property required as a carrier while maintaining the mechanical strength of the mesh.
The aperture ratio of the electrode can be measured by the following method.
An electrode based on expanded metal is cut out to a size of about 5 mm × 5 mm, and a desktop microscope Miniscope TM3000 (manufactured by Hitachi High-Technologies Corporation) is used to switch the distance between the centers in the short direction and the distance between the centers in the long direction. The LW, the bond length B, the length SWO in the single direction of the opening, and the length LWO in the long direction of the opening were measured. Using these values, the aperture ratio was calculated according to the following formula.
Aperture ratio = SWO x (LWO + B) x 100 / (SW x LW)
Further, for the electrode using the plain weave mesh as the base material, the opening A and the wire diameter d were similarly measured using TM3000, and the aperture ratio (%) was calculated according to the following formula.
Aperture ratio = (A / (A + d)) ² x 100
The method of calculating the aperture ratio of the electrode differs between the electrode using the expanded metal as the base material and the electrode using the plain weave mesh as the base material. The opening ratio of an electrode using a base material other than expanded metal or plain woven mesh is such that the electrode is cut out to a predetermined size (for example, about 5 mm × 5 mm) and placed horizontally from the upper side in the vertical direction of the central portion of the electrode. Light is projected, the electrode is projected downward in the vertical direction, the total area of the portion through which the light is transmitted and the projected area of the electrode (total area of shadow and transmitted light) are measured, and the calculation is performed according to the following formula. be able to.
Aperture ratio = (total area of light-transmitted part) / (projected area of electrode) x 100

--Manufacturing method of cathode for alkaline water electrolysis ---
The method for producing the cathode for alkaline water electrolysis according to the present embodiment may be the same as the method for producing 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 bordered.

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

-Electrode chamber-
In the multipolar electrolytic cell 50 of the present embodiment, as shown in FIG. 2, the partition wall 1, the outer frame 3, and the diaphragm 4 define an electrode chamber 5 through which the electrolytic solution passes.

-Gasket-
In the multi-pole electrolytic cell 50 for alkaline water electrolysis of the present embodiment, it is preferable that a gasket 7 having a diaphragm 4 is sandwiched between outer frames 3 that border the partition wall 1.
The gasket 7 is used to seal between the multi-pole element 60 and the diaphragm 4 and between the multi-pole element 60 against the electrolytic solution and the generated gas, and leaks the electrolytic solution and the generated gas to the outside of the electrolytic cell. Gas mixing between the bipolar cells can be prevented.

-Charge holder-
In the multi-pole electrolytic cell 50 for alkaline water electrolysis of the present embodiment, as shown in FIG. 2, the conductive elastic body 2e and the current collector 2r are conductive between the cathode 2c or the anode 2a 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 cell.
The charge holder preferably contains nickel in the base material because it has high durability against alkali, has a redox potential with respect to the anode, and can reduce the anode when electrolysis is stopped. The matrix may contain at least one selected from nickel oxide, metallic nickel, nickel hydroxide and nickel alloys.

The cathode chamber further contains the conductive elastic body 2e and the current collector 2g, and the conductive elastic body 2e is compressed and accommodated in a state of being electrically connected between the cathode chamber and the current collector. , A part of the cathode current collector may be composed of the charge holder. As a result, it is possible to suppress an increase in the weight of the cell due to the additional attachment of the charge holder.

The surface layer of the charge holder 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 contain an alloy composed of nickel and other metals. It is particularly preferred that the surface layer is made 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, platinum group, rare earth elements and the like.

The method for manufacturing the charge holder is not particularly limited, and examples thereof include a manufacturing method similar to that for the anode.

-Header-
The multi-pole electrolytic cell 50 for alkaline water electrolysis has a cathode chamber 5c and an anode chamber 5a for each electrolysis cell 65. In order to continuously carry out the electrolysis reaction in the electrolytic cell 50, it is necessary to continuously supply an electrolytic solution containing a sufficient amount of raw materials consumed by electrolysis to the cathode chamber 5c and the anode chamber 5a of each electrolytic cell 65. There is.

The electrolytic cell 65 is connected to an electrolytic solution supply / discharge pipe called a header 10 which is common to the plurality of electrolytic cells 65. Generally, the anode liquid distribution pipe is called an anode inlet header 10ai, the cathode liquid distribution pipe is called a cathode inlet header 10ci, the anode liquid collection pipe is called an anode outlet header 10ao, and the cathode liquid collection pipe is called a cathode outlet header 10co. The electrolytic 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 use a material that can sufficiently withstand the corrosiveness of the electrolytic solution 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, and the detailed structure of the outer frame 3 is the header 10 (electrolytic) attached to the outer frame 3. It may differ depending on the arrangement mode of the tube for distributing or collecting the liquid. As the arrangement mode of the header 10 of the multi-pole electrolytic cell 50, the inner header 10I type and the outer header 10O type are typical.

-Internal header-
The internal header 10I type refers to a type in which a multi-pole electrolytic cell 50 and a header 10 (a tube for distributing or collecting an electrolytic solution) are integrated.

In the internal header 10I type multi-pole electrolytic cell 50, more specifically, the anode inlet header 10Iai and the cathode inlet header 10Ici are provided in the partition wall 1 and / or in the lower part in the outer frame 3, and are provided in the partition wall 1. The anode outlet header 10Iao and the cathode outlet header 10Ico are provided so as to extend in the vertical direction, and are provided in the partition wall 1 and / or in the upper part in the outer frame 3, and are provided in the direction perpendicular to the partition wall 1. It is provided to extend.

The anode inlet header 10Iai, the cathode inlet header 10Ici, the anode outlet header 10Iao, and the cathode outlet header 10Ico inherently contained in the internal header 10I type multi-pole electrolytic cell 50 are collectively referred to as the internal header 10I.

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

− External header −
The external header 10O type refers to a type in which the bipolar electrolytic cell 50 and the header 10 (tube for distributing or collecting the electrolytic solution) are independent.

The external header 10O type multi-pole electrolytic cell 50 is independent in that the anode inlet header 10Oai and the cathode inlet header 10Oci run in parallel with the electrolytic cell 50 in the direction perpendicular to the energizing surface of the electrolytic cell 65. Is provided. The anode inlet header 10Oai and the cathode inlet header 10Oci are connected to each electrolytic cell 65 by a hose.

The external header 10O, the anode inlet header 10Oai, the cathode inlet header 10Oci, the anode outlet header 10Oao, and the cathode outlet header 10Oco, which are externally connected to the external header 10O type multi-pole electrolytic cell 50, are collectively referred to as the external header 10O. Call.
In the example of the outer header 10O type, a tubular member is installed in a through hole for the header 10 provided in a portion located below the outer frame 3 at the edge of the partition wall 1, and the tubular member is formed. , Connected to the anode inlet header 10Oai and the cathode inlet header 10Oci, and similarly, through the header 10 through hole provided in the upper portion of the outer frame 3 at the edge of the partition wall 1. A luminal member (eg, hose, tube, etc.) is installed, and the luminal member is connected to the anode outlet header 10Oao and the cathode outlet header 10Oco.

(Electrolyzer for alkaline water electrolysis)
FIG. 5 shows an outline of the electrolyzer for alkaline water electrolysis of the present embodiment.
By using the bipolar water electrolytic cell of the present embodiment as an electrolyzer including other elements and using it as a hydrogen production device, a hydrogen production device having high electrolysis efficiency can be provided.
The electrolyzer for alkaline water electrolysis of the present embodiment is at least the bipolar water electrolysis tank 50, the gas-liquid separation tank 72 (hydrogen separation tank 72h, oxygen separation tank 72o), the electrolytic solution circulation pump 71, and water of the present embodiment. It includes an input pump 73 and a rectifier 74 for supplying power for electrolysis.
In addition to the above, the electrolytic device 70 for alkaline water electrolysis of the present embodiment may include an oxygen concentration meter 75, a hydrogen concentration meter 76, a flow meter 77, a pressure gauge 78, a heat exchanger 79, and a pressure control valve 80.

According to the alkaline water electrolysis electrolyzer 70 of the present embodiment, the effect 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 when operating with a variable power source such as renewable energy, and reduce self-discharge generated when the power supply is stopped. It is possible to stabilize the electric control system. According to the present embodiment, it is possible to further realize highly efficient storage of electric power, specifically, reduction of pump power and reduction of leakage current.

(Alkaline water electrolysis method)
The alkaline water electrolysis method of the present embodiment can be carried out by using the alkaline water electrolysis apparatus 70 of the present embodiment.

With reference to the drawings, the bipolar electrolysis tank for alkaline water electrolysis, the electrolyzer for alkaline water electrolysis, and the alkaline water electrolysis method according to the embodiment of the present invention have been exemplified and described above. The type electrolysis tank, the electrolyzer for alkaline water electrolysis, and the method for electrolyzing alkaline water are not limited to the above examples, and the above embodiments can be appropriately modified.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to the following Examples.

A multi-pole cell for alkaline water electrolysis and an alkaline water electrolyzer using the same were manufactured as follows.

-Septum, outer frame-
As the multi-pole element, an element provided with a partition wall for partitioning the anode and the cathode and an outer frame 3 surrounding the partition wall was used. Nickel was used as the material for the members that come into contact with the electrolytic solution, such as the partition wall and the frame of the multi-pole element.

− Anode −
A blast treatment was performed using an expanded nickel aperture ratio (50%) as the conductive substrate. The conductive base material was adjusted to 50 cm square by cutting to prepare an anode sample A.
Anode sample A was immersed in a 5N-HCl aqueous solution for 10 minutes to prepare anode sample B.
Using the anode sample B, the Raney nickel alloy was coated by dispersion plating and immersed in a 32 wt%, 80 ° C. NaOH aqueous solution for 10 hours to dissolve Al in the Raney nickel alloy. Anode sample C was obtained by the above step.
Six anode samples C were stacked and laminated, and the anode samples D were connected so as to have the same potential.
Eight anode samples C were stacked and laminated, and the anode samples E were connected so as to have the same potential.

Blasting was performed using expanded nickel as the conductive substrate. In the same manner as described above, the conductive base material was adjusted to a 50 cm square by cutting to prepare an anode sample A. In the same manner as described above, the anode sample A was immersed in a 5N-HCl aqueous solution for 10 minutes to prepare an anode sample B. Using the anode sample B, the Raney nickel alloy was coated with dispersion plating for 8 times as long as the anode sample C, and immersed in a 32 wt%, 80 ° C. NaOH aqueous solution for 10 hours to dissolve Al in the Raney nickel alloy. An anode sample F was obtained by the above step.

((Measurement of anode (oxygen electrode) potential of anode sample))
One anode samples A, B, C, D, E, and F were prepared, and a fluororesin beaker was filled with an electrolytic solution of 30 wt% KOH and immersed therein. The temperature of the aqueous solution of KOH was maintained at 90 ° C. An anode sample, a platinum wire mesh (counter electrode), and a fluororesin cylinder that covers the counter electrode, and these devices ensure electrical conductivity. Oxidation of a current density of 0.4 A / cm ^{2 with} respect to the anode sample. An electric current was applied to generate hydrogen for 30 minutes. Then, a reduction current of 0.05 A / cm ² was passed, and the change in the potential of the anode sample was measured. This potential change was plotted against the total charge (elementary charge) of the applied current to obtain an oxidation curve of the anode sample.

The measurement was carried out at a temperature of 90 ° C. using a mesh-shaped platinum electrode as a counter electrode. As the fluororesin cylinder, a cylinder having a large number of holes of 1 mmφ was used. The anode potential of the anode sample was measured by the three-electrode method using a Luggin capillary to eliminate the effect of ohm loss due to liquid resistance. The distance between the tip of the Luggin capillary and the anode was always fixed at 0.05 mm. Silver-silver chloride (Ag / AgCl) was used as the reference electrode for the three-electrode method.

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

The positive charge (elementary charge) of the anode sample A was 3667 C / m ² . The positive charge (elementary charge) of the anode sample B was 5018 C / m ² . The positive charge (elementary charge) of the anode sample C was 148610 C / m ² . The positive charge (elementary charge) of the anode sample D was 955350 C / m ² . The positive charge (elementary charge) of the anode sample E was 1061500 C / m ² . The positive charge (elementary charge) of the anode sample F was 445830 C / m ² .

The actual specific surface area of each of the anode samples A, B, C, and F was measured. The actual specific surface areas of the anode samples D and E per anode of the anode sample were the same as those 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 the first pore and the second pore of the catalyst layer of the anode))
The specific surface area of the first pores in which the pore size 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 the anode samples A and B, and 1.5 m for the anode samples C, D, and E. ^{It was 2} / g and the anode sample F was 4.5 m ² / g.
The pore volume of the first pores is ^10-6 ml / g or less for the anode samples A and B, 4 × 10 ^-4 ml / g for the anode samples C, D, and E, and 5 × ^{10-5 for the} anode sample F. It was ml / g.
The specific surface area of the second pores in which the pore size 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 the anode samples A and B, 0.1 ml / g for the anode samples C, D, and E, and 0.45 ml / g for the anode sample F.

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

− Cathode −
A micromesh (wire diameter: 0.1 mm, 50 mesh) -shaped active cathode (Pt-based pyrolysis active cathode) was cut into a 50 cm square to prepare a cathode.

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

The cathode was adjusted to a length of 50 cm and a length of 50 cm to prepare a cathode sample G.
The structure was adjusted to a length of 50 cm and a width of 5.73 cm and superposed on the cathode sample G to obtain a cathode sample A.
The structure was adjusted to a length of 50 cm and a width of 0.73 cm and superposed on the cathode sample G to obtain a cathode sample B.
The structure was adjusted to a length of 50 cm and a width of 11.98 cm and superposed on the cathode sample G to obtain a cathode sample C.
The structure was adjusted to a length of 50 cm and a width of 18.86 cm and superposed on the cathode sample G to obtain a cathode sample D.
The structure was adjusted to a length of 50 cm and a width of 50 cm, and three layers of the structure were overlapped with the cathode sample G to obtain a cathode sample E.
The structure was adjusted to a length of 50 cm and a width of 50 cm, and a stack of four of these was superposed on the cathode sample G to obtain a cathode sample F.

(Electrical capacity of anode and cathode)
The electric capacities (C / m ² ) of the anode and cathode of the electrolytic cell were 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 a fluororesin beaker was filled with an electrolytic solution of 30 wt% KOH and immersed therein. The temperature of the aqueous solution of KOH was maintained at 90 ° C. Cathode sample, comprising a cylinder of platinum wire mesh electrode (counter electrode) and the fluororesin covering around the counter electrode, an apparatus in which these electrical conductivity is ensured, with respect to the cathode sample, reduction of the current density 0.4 A / cm ² An electric current was applied to generate hydrogen for 30 minutes. Then, an oxidation current of 0.05 A / cm ² was passed, and the change in the potential of the cathode sample was measured. This potential change was plotted against the total charge amount of the applied current to obtain an oxidation curve of the cathode sample.

The measurement was carried out at a temperature of 90 ° C. using a mesh-shaped platinum electrode as a counter electrode. As the fluororesin cylinder, a cylinder having a large number of holes of 1 mmφ was used. The cathode (hydrogen electrode) potential of the cathode sample was measured by the three-electrode method using a Luggin capillary to eliminate the effect of ohm loss due to liquid resistance. The distance between the tip of the Luggin capillary and the cathode sample was always fixed at 0.05 mm. Silver-silver chloride (Ag / AgCl) was used as the reference electrode for the three-electrode method.

((Measurement of negative charge (elementary charge) stored in the cathode chamber when hydrogen is generated))
For the cathode samples A, B, C, D, E, F, and G, the total current applied until the cathode potential reaches -0.8 V (vs. Ag / AgCl) in the measured oxidation curve of the cathode sample. The amount of charge was defined as the amount of negative charge (electric capacity) stored in the cathode chamber when hydrogen was generated.

The negative charge (elementary charge) of the cathode sample A was 48250 C / m ² . The negative charge (elementary charge) of the cathode sample B was 9650 C / m ² . The negative charge (elementary charge) of the cathode sample C was 96500 C / m ² . The negative charge (elementary charge) of the cathode sample D was 149575 C / m ² . The negative charge (elementary charge) of the cathode sample E was 868500 C / m ² . The negative charge (elementary charge) of the cathode sample F was 1158,000 C / m ² . The negative charge (elementary charge) of the cathode sample G was 3956.5 C / m ² .

The electrolytic cell used in this embodiment is an electrolytic cell including a cathode chamber having a cathode, an anode chamber having an anode, a diaphragm separating the cathode chamber and the anode chamber, and the cathode chamber and the electrolytic solution filled in the anode chamber. Was to be provided. The electrolytic cell was provided with a cathode chamber having a cathode, an anode chamber having an anode, and a diaphragm separating the cathode chamber and the anode chamber. The cathode chamber and the anode chamber were arranged so as to face each other via a diaphragm. The cathode chamber and the anode chamber were filled with an electrolytic solution, respectively. As the cathode, anode, diaphragm, and electrolytic solution, known materials used in the electrolysis of water were used.

-Septum-
A diaphragm sample was prepared by cutting a polysulfone-based porous membrane into a 50 cm square.

-Multi-pole electrolytic cell, multi-pole element-
Forty-nine multi-pole elements are used, and as shown in FIG. 1, a fast head, an insulating plate, and an anode terminal unit are arranged on one end side, and further, an anode side gasket part, a diaphragm, and a cathode side gasket part, Forty-nine sets of multi-pole elements arranged in this order were arranged, and further, an anode-side gasket portion, a diaphragm, and an electrocathode-side gasket portion were arranged to assemble a multi-pole electrolytic cell.
In this embodiment, the cathode chamber and the anode chamber each had a 50-pair series connection structure with 50 chambers.

-Gasket-
As the gasket, EPDM rubber was used as the material.

-Header, conduit-
An external header type multi-pole element is used.
As shown in FIG. 4, in the multi-pole electrolytic cell 50 of this embodiment, the conduit 20 (anode liquid distribution tube 20Oai) for distributing and collecting the electrolytic solution is outside the housing of the electrolytic cell 50. , Cathode liquid distribution tube 20Oci, anode liquid collecting tube 20Oao, cathode liquid collecting tube 20Oco) were provided. Further, in the electrolytic cell 50, hoses (anode inlet header 10Oai, cathode inlet header 10Oci, anode outlet header 10Oao, cathode outlet header 10Oco) as headers 10 for passing the electrolytic solution from these conduits 20 to the electrode chamber 5 are provided. Attached from the outside.
Here, as shown in FIG. 4, all of the headers 10 (anode inlet header 10Oai, cathode inlet header 10Oci, anode outlet header 10Oao, cathode outlet header 10Oco) are from the side of the partition wall 1 of the multipolar element 60. It was arranged so as to extend outward. Further, as shown in FIG. 4, all of the conduits 20 (anode liquid distribution pipe 20Oai, cathode liquid distribution pipe 20Oci, anode liquid collection pipe 20Oao, cathode liquid collection pipe 20Oco) are multipolar elements 60. It was arranged so as to extend in the direction perpendicular to the partition wall 1.
In this way, the external header 10O type electrolytic cell 50 was produced.
The electrolytic solution was flowed from the cathode chamber 5c to the cathode chamber 5c via the cathode inlet header 10Oci and through the cathode outlet header 10Oco. Further, the electrolytic solution was flowed from the anode chamber 5a to the anode chamber 5a via the anode inlet header 10Oai and through the anode outlet header 10Oco.
As shown in FIG. 4, the inlet hose is on one end side of the lower side of the rectangular outer frame 3 in a plan view, and the outlet hose is on the upper side of the side side connected to the other end side of the lower side of the rectangular outer frame 3 in a plan view. , Each is connected. Here, the inlet hose and the outlet hose are provided so as to face each other with the central portion of the electrode chamber 5 in the rectangular electrode chamber 5 in a plan view. The electrolytic solution flowed from the bottom to the top while inclining in the vertical direction, and rose along the electrode surface.
In the multi-pole electrolytic cell 50 of this embodiment, the electrolytic solution flows into the anode chamber 5a and the cathode chamber 5c from the inlet hose of the anode chamber 5a and the cathode chamber 5c, and from the outlet hose of the anode chamber 5a and the cathode chamber 5c. The structure is such that the electrolytic solution and the generated 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 above-mentioned cathode outlet header 10Oco, a mixed phase flow of the electrolytic solution and hydrogen gas occurs, and the anode outlet header At 10Oao, the flow was a mixed phase of the electrolytic solution and the oxygen gas.

(Example 1)
The multi-pole electrolytic cell of Example 1 was produced by the following procedure.

The cathode sample A was attached to the cathode surface of the multi-pole frame, and the anode sample C was attached to the anode surface of the frame of the multi-pole element to form a multi-pole element. Further, a cathode sample A attached to the frame of the cathode terminal element was used as a cathode terminal element. The anode sample C attached to the frame of the anode terminal element was designated as the anode terminal element.

The area S1 of the electrodes (anode and cathode) attached to the multi-pole element was adjusted to 0.25 m ² .
The cross-sectional area S2 of the flow path of the headers (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 multi-pole element was adjusted to 33 mm. Further, the thickness of the cathode terminal element and the anode terminal element was adjusted to 0.0125 m.

Forty-nine multi-pole elements were prepared. Further, the cathode terminal element and the anode terminal element were prepared one by one.

Gaskets were attached to the metal frame parts of all multi-pole elements, cathode terminal elements, and anode terminal electrolytic cell elements.

A diaphragm sample was sandwiched between the anode terminal element and the cathode side of the multipolar element. Forty-nine multi-pole elements are arranged in series so that one anode side and the other cathode side of the adjacent multi-pole elements face each other, and 48 elements are placed between the adjacent multi-pole elements. The diaphragm samples of the above were sandwiched one by one. Further, one diaphragm sample was sandwiched between the anode side of the 49th multi-pole element and the cathode terminal element. These were tightened with a press after using a fast head, an insulating plate, and a loose head, and used as the multi-pole electrolytic cell of Example 1.

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

A current was passed from the rectifier to the multi-pole electrolytic cell so as to be 6 kA / m ² for the area S1 of each cathode and anode. In Example 1, since the electrode area S1 is 500 mm × 500 mm, 1.5 kA was applied from the rectifier to the multi-pole electrolytic cell.

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. The pressure was adjusted by a pressure control valve installed downstream of the pressure gauge.

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

(Electrolysis test)
Water electrolysis was performed by continuously energizing for 8 hours at a current density of 6 kA / m ² . 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 energizing continuously for 7 hours at a current density of 6 kA / m ² , the power of the rectifier was turned off and the cell voltage V was continuously measured. The potential holding time T (hour) was defined as the time during which the arithmetic mean of the cell voltage V was held at 1 V or more based on the time immediately after the electrolysis was stopped.

(Manufacturability)
The manufacturability of the electrolytic cell was evaluated according to the following evaluation criteria. 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 △ (Good): The number of welding points required to fix the electrode to the electrolytic cell is 500 points / m ² or more. Less than 1500 points / m ² x (defective): The number of welding points required to fix the electrode to the electrolytic cell is 1500 points / m ² or more.

(Example 2)
A multi-pole electrolytic cell 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 shown in Table 1.

(Example 3)
A bipolar electrolytic cell and an electrolytic device for alkaline water electrolysis were produced in the same manner as in Example 1 except that the cathode sample was the cathode sample B, S1 was adjusted to 2.7 m ² , and L2 was adjusted to 2.4 m. Detailed conditions and results are shown in Table 1.

(Example 4)
A multi-pole electrolytic cell and an electrolyzer 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 L2 was adjusted to 2.4 m. Detailed conditions and results are shown in Table 1.

(Example 5)
A multi-pole electrolytic cell and an electrolyzer 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 L2 was adjusted to 6.5 m. Detailed conditions and results are shown in Table 1.

( Reference example 6)
A multi-pole electrolytic cell and an electrolytic device 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 shown in Table 1.

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

(Example 8)
A multi-pole electrolytic cell and an electrolyzer 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 L2 was adjusted to 7.2 m. Detailed conditions and results are shown in Table 1.

(Example 9)
A multipolar electrolytic cell and an alkaline water electrolyzer were produced in the same manner as in Example 1 except that S2 was adjusted to 7.85 × ^10-7 m ² and L2 was adjusted to 2.4 m. Detailed conditions and results are shown in Table 1.

( Reference example 10)
A bipolar electrolytic cell and an electrolytic device for alkaline water electrolysis were produced in the same manner as in Example 1 except that the cathode sample was the cathode sample C and S2 was adjusted to 7.85 × ^10-7 m ² . Detailed conditions and results are shown in Table 1.

(Example 11)
The anode sample was the anode sample B, S2 was adjusted to 1.77 × ^10-6 m ² , and L2 was adjusted to 1 m. The multi-pole electrolytic cell and the electrolyzer for alkaline water electrolysis were used in the same manner as in Example 1. Made. Detailed conditions and results are shown in Table 1.

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

(Example 13)
A multi-pole electrolytic cell and an electrolytic device 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 100. Detailed conditions and results are shown in Table 1.

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

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

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

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

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

(Comparative Example 5)
A multi-pole electrolytic cell and an electrolyzer were produced in the same manner as in Example 1 except that the anode sample was the anode sample E. Detailed conditions and results are shown in Table 1.

In Examples 1 to 5, Reference Example 6, Examples 7 to 9, Reference Example 10, and Examples 11 to 14, electrolysis is possible at 1.85 V or less, the potential holding time is 3 hours or more, and system control is performed. The result was stable enough to do so. Further, in Examples 1 to 5, Reference Example 6, Examples 7 to 9, Reference Example 10, and Examples 11 to 13 in which the actual electrode surface area of the anode is 10000 m ² / m ² or less, the cell voltage can be further lowered. did it. In particular, the electrolytic cells of Examples 2, 4 and 7 are excellent.
On the other hand, those of Comparative Examples 1, 3 and 5 have poor electrolytic efficiency, and those of Comparative Examples 2 to 4 have a short potential holding time, and are used in a variable power source such as renewable energy such as wind power and solar power. It has been shown that there are practical problems in using the electrolytic cell as an emergency storage battery when the power supply is stopped and in operating the electric control system stably even in an emergency.

According to the present invention, it is possible to enable long-term storage and long-distance transportation of a large amount of electric power when operating with a variable power source such as renewable energy, and to stabilize an electric control system when the electric power supply is stopped.

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 Cathode electrolyte inlet 5co Cathode electrolyte outlet 6 rectifying plate 6a Anode rectifying plate (anode rib)
6c Cathode rectifying plate (cathode rib)
7 Gasket 10 Header 10I Internal Header 10O External Header 10Oai 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)
20 Conduit 20Oai Anode liquid distribution pipe 20Oao Anode liquid collection pipe 20Oci Cathode liquid distribution pipe 20Oco Cathode liquid collection pipe 50 Multipolar electrolytic tank 51g Fast head, loose head 51a Anode terminal element 51c Cathode terminal element 51i Insulation plate 51r Tie rod 60 Multipolar element 65 Electrolyzer cell 70 Electrolyzer 71 Electrolyte solution circulation pump 72 Gas-liquid separation tank 72h Hydrogen separation tank 72o Oxygen separation tank 73 Water input pump 74 Rectifier 75 Oxygen concentration meter 76 Hydrogen concentration meter 77 Flowmeter 78 Pressure gauge 79 Heat exchanger 80 Pressure control valve D1 Given direction along the bulkhead (electrolyte passage direction)
S1 Area of the current-carrying surface of the multi-pole element S2 Cross-sectional area of the header flow path L2 Header flow path length Z Zero gap structure d Electrolytic cell thickness

Claims (23)

A plurality of bipolar elements including an anode, a cathode, a partition wall separating the anode and the cathode, and an outer frame framing the partition wall are superposed on the outer side of the outer frame with a diaphragm in between. A multi-pole electrolytic cell including a partition wall, an outer frame, and a header communicating with an electrode chamber defined by the diaphragm.
The capacitance of the anode is in a range of ^{4825C / m 2 ~965000C / m 2} , the capacitance of the cathode Ri range der of ^{4825C / m 2 ~965000C / m 2} ,
When the area of the energizing surface of the multi-pole 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 1.31. It is in the range of × 10 ^-6 m ^{-1 to} 2.3 × 10 ^-4 m ^-1 .
A multi-pole electrolytic cell characterized by this. A plurality of bipolar elements including an anode, a cathode, a partition wall separating the anode and the cathode, and an outer frame framing the partition wall are superposed on the outer side of the outer frame with a diaphragm in between. A multi-pole electrolytic cell including a partition wall, an outer frame, and a header communicating with an electrode chamber defined by the diaphragm.
The capacitance of the anode is in a range of ^{4825C / m 2 ~965000C / m 2} , the capacitance of the cathode Ri range der of ^{4825C / m 2 ~965000C / m 2} ,
When the area of the energizing surface of the multi-pole 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 1.31. It is in the range of × 10 ^-6 m ^{-1 to} 2.3 × 10 ^-4 m ^-1 .
A multi-pole electrolytic cell for alkaline water electrolysis, which is characterized by this. The bipolar electrolytic cell according to claim 1 or 2 , wherein the lower of the electric capacity of the anode and the electric capacity of the cathode is in the range of 9650 C / m ^{2 to} 955 350 C / m ² . The bipolar electrolytic cell according to any one of claims 1 to 3 , wherein the electric capacity of the anode is larger than the electric capacity of the cathode. The bipolar electrolytic cell according to claim 4 , wherein the electric capacity of the cathode is more than 0.1 times the electric capacity of the anode and 0.99 times or less. The multi-pole electrolytic cell according to claim 4 or 5 , wherein the electric capacity of the cathode is more than 0.1 times and 0.49 times or less 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 1-6. The multi-pole electrolytic cell according to any one of claims 1 to 7 , which has 50 to 500 multi-pole elements. Wherein S1 is a 0.1 m ² through 10m ^2, a bipolar type electrolytic cell according to any one of claims 1-8. The multipolar electrolytic cell according to any one of claims 1 to 9 , wherein the electrolytic cell has a thickness d of 10 mm to 100 mm. The bipolar electrolytic cell according to any one of claims 1 to 10 , 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 has a conductive base material and a catalyst layer arranged on the conductive base material.
The catalyst layer contains nickel metal crystals and has pores.
Of the pores of the catalyst layer,
The specific surface area of the first pores having a pore diameter 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 pore 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 multi-pole electrolytic cell according to any one of claims 1 to 11 . At least one Pt group whose cathode is selected from the group consisting of Ru-La-Pt system, Ru-Ce system, Pt-Ce system, and Pt-Ir system, Ir-Pt-Pd system, and Pt-Ni system. The bipolar electrolytic cell according to any one of claims 1 to 12 , which contains a compound. The structure of the cathode and the anode has a catalyst layer on the surface of the conductive base material, and the conductive base material is at least selected from the group consisting of metallic nickel, nickel oxide, nickel hydroxide, and a nickel alloy. The bipolar electrolytic cell according to claim 13 , which comprises a kind of nickel compound. The bipolar electrolytic cell according to any one of claims 1 to 14 , wherein the cathode and the anode have a mesh-like structure. The duplex according to any one of claims 1 to 15 , 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 bipolar electrolytic cell according to any one of claims 1 to 16 , wherein the base material of the anode has a mesh-like structure having an aperture ratio in the range of 20% to 60%. The multi-pole electrolytic cell according to claim 1 to 17 , wherein the electrolytic cells are electrically connected in series. A bipolar element having the cathode, the anode, the diaphragm, and a partition partitioning the anode chamber and the cathode chamber is provided, the diaphragm is located between the cathode and the anode, and the anode is in contact with the cathode and the anode. The bipolar water electrolytic cell according to claim 18 . The bipolar electrolytic cell according to any one of claims 1 to 19 , an electrolytic solution circulation pump for circulating an electrolytic solution, and a gas-liquid separation tank for separating an electrolytic solution and hydrogen and / or oxygen. An electrolyzer characterized by including a water injection pump for replenishing water. The electrolyzer according to claim 20 , further comprising a detector that detects the stop of the power supply when the power supply to the electrolyzer is stopped, and a controller that automatically stops the electrolytic solution circulation pump. A water electrolysis method, which comprises stopping the electrolytic solution circulation pump when the power supply to the electrolytic device according to claim 20 or 21 is stopped. In a hydrogen production method for producing hydrogen by electrolyzing water containing alkali in an electrolytic cell,
In the electrolytic cell, a plurality of multi-pole elements including an anode, a cathode, a partition wall separating the anode and the cathode, and an outer frame bordering the partition wall are superposed with a diaphragm interposed therebetween. A multi-pole electrolytic cell having a partition wall, an outer frame, and a header communicating with an electrode chamber defined by the diaphragm on the outside of the frame, and the electric capacity of the anode is 4825 C / m ^{2 to} 965000 C. / ^m is in the range of ^2, the capacitance of the cathode Ri range der of ^{4825C / m 2 ~965000C / m 2} , the cross-sectional area of the Fukukyokushiki the area of the energizing surface of the element S1, the flow path of the header Is S2, and when the length of the flow path of the header is L2, (S2 / S1) / L2 is in the range of 1.31 × 10 ^-6 m ^{-1 to} 2.3 × 10 ^-4 m ^-1 . characterized Rukoto Oh, hydrogen production process.

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