JP2003160891A - Clamping device in solid polymer type water electrolytic cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a solid polymer type water electrolytic cell, which can easily deliver a stable electrolytic operation regardless of an operating pressure and the pressure fluctuation, through operating the cell under a constant clamping pressure, when operating the solid polymer type water electrolytic cell in an arbitrary operating pressure, or when changing the operating pressure to an optional pressure. <P>SOLUTION: A clamping device 21 uniformly clamps a set consisting of a main anode 1, several unit cells 16, and a main cathode 2 with a flange 33 arranged in one side of the set and a compression mechanism 34 arranged in the other side. The compression mechanism 34 comprises a cylinder 37 having an introduction nozzle for a compressing fluid 35, an exhaust nozzle 36 and a piston 39 arranged in the cylinder 37 through an O-ring 38. The flange 33 is coupled with the cylinder 37 through a bolt 14 and a nut 15. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a water electrolysis cell for producing hydrogen and oxygen using a solid polymer electrolyte membrane, that is, an electrode assembly membrane. More specifically, the present invention relates to the operation of a solid polymer type water electrolyzer with respect to an arbitrary operating pressure or pressure fluctuations under a fixed absolute clamping pressure regardless of the operating pressure and pressure fluctuations.
Tighten multiple unit cell-cathode main electrode combinations,
The present invention relates to a tightening device in a solid polymer type water electrolysis cell that enables stable electrolysis performance to be exhibited.

[0002]

2. Description of the Related Art Conventionally, a laminated water electrolysis cell for producing hydrogen and oxygen by water electrolysis using a solid polymer electrolyte membrane has an anode main electrode (1) arranged at both ends as shown in FIG.
And a cathode main electrode (2), a plurality of unit cells (16) arranged in series between these main electrodes (1) (2), and an anode main electrode
(1) -It is mainly composed of a tightening device that tightens the combination of a plurality of unit cells (16) -cathode main electrode (2) from both sides.

One cell (16) is the anode side of the bipolar plate (9),
Anode power supply (7), solid polymer electrolyte membrane (3), namely electrode assembly film, cathode power supply (8), backup metal for reinforcing cathode power supply, O-ring for sealing inside and outside of electrolytic cell, inside cell Hydrogen generation area-manifold gasket that seals the oxygen generation area and adjacent bipolar plate (9)
From the cathode side of.

The solid polymer electrolyte membrane (3) is an ion exchange membrane.
(4) and catalyst electrode layer plated with precious metal on both sides (5)
(6) consists of and. The number of unit cells is 30 to 600 in commercial scale electrolytic cells.

In the electrolyzer having the above structure, when water is supplied from the water supply header (10) at the lower part of the electrolyzer into each unit cell, it is electrolyzed on the surfaces of the catalyst electrode layers (5) and (6), and the anode side Then, oxygen is generated, and hydrogen is generated on the cathode side. The generated oxygen and hydrogen reach the anode side and the cathode side of the bipolar plate (9) through the porous power feeders (7) and (8), respectively, and further through the vertical flow paths provided in the bipolar plate. It reaches the upper part of the electrolytic cell and is discharged to the outside through the oxygen header (11) and the hydrogen header (12) on the upper part of the electrolytic cell.

According to the experiments by the present inventors, as shown in FIG. 5, the temperature was 70 ° C. and the current density was 1 A by the tightening device.
Anode main electrode (1) -plural unit cells (16)-/ cm ²
The tightening pressure of the combination of the cathode main electrode (2) (hereinafter simply referred to as “tightening pressure”) is 4 kg.
If it is f / cm ² G or less, the electrolysis voltage becomes high, hydrogen cannot be produced with high efficiency, and the tightening pressure is 4 k.
It was found that when it is at least gf / cm ² G, the solid polymer electrolyte membrane may creep after long-time operation, and the material may deteriorate due to thinning. Therefore, in order to efficiently operate the solid polymer type water electrolysis cell in a stable state, it is necessary to constantly maintain the tightening pressure at about 4 kgf / cm ² G. That is, when hydrogen is generated by normal pressure operation, it is necessary to always operate at a tightening pressure of about 4 kgf / cm ² G.

In order to obtain this tightening pressure, conventionally,
Anode main electrode (1) -Multiple unit cells (16) -Cathode main electrode (2)
A pair of left and right flanges (13) that sandwich the combination of
Bolts (14) and nuts hung on these flanges
It was tightened by (15).

[0008]

In the above electrolytic cell,
To produce hydrogen not only at a constant pressure but also at an arbitrary pressure, 4 kgf / cm ² is applied at an arbitrary hydrogen pressure.
It is necessary to operate with G tightening pressure applied. For example, in order to generate hydrogen efficiently and stably at 4 kgf / cm ² G, it is necessary to operate at 8 kgf / cm ² G. Further, when it is desired to change the operating pressure to an arbitrary pressure during the operation, it is necessary to perform the operation in a state where the tightening pressure of 4 kgf / cm ² G is always applied to the arbitrary electrolytic pressure. In this case, it is practically difficult to re-tighten the bolt and the nut during operation, which is a complicated and dangerous work.

In view of the above situation, an object of the present invention is to operate the solid polymer type water electrolyzer at an arbitrary operating pressure, or to change the operating pressure to an arbitrary operating pressure. An object of the present invention is to provide a solid polymer type water electrolyzer which can be operated under a constant absolute tightening pressure and can exhibit stable electrolysis performance simply and irrespective of pressure fluctuations.

[0010]

According to the present invention, there are provided an anode main electrode and a cathode main electrode arranged at both ends, a plurality of unit cells arranged in series between these main electrodes, and an anode main electrode-a plurality of unit cells. In a solid polymer water electrolyzer mainly composed of a tightening device for tightening the unit cell-cathode main electrode combination from both sides, the tightening device includes an anode main electrode-a plurality of unit cells-a cathode main electrode combination. A fastening device in a solid polymer type water electrolyzer, characterized in that it is fastened by a flange arranged on one side thereof and a pressurizing mechanism arranged on the other side.

In the first embodiment, in the pressurizing mechanism, the piston is extruded from the cylinder by the pressure applied to the pressurizing mechanism by the introduction of the fluid into the cylinder, and the anode main electrode-
It presses a combination of a plurality of unit cells-cathode main electrodes. The pressurizing mechanism preferably detects any pressure or pressure fluctuation of oxygen or hydrogen generated during the operation of the water electrolysis tank, and applies pressure to the pressurizing mechanism by introducing a fluid into the cylinder (herein Throughout the entire process, simply detect the "pressure applied to the pressurizing mechanism"), detect the difference between these two pressures, and make sure that the pressure detected by the latter is greater than the pressure detected by the former by the tightening pressure. It is provided with a sequence control mechanism for adjusting the amount of fluid introduced into the inside.

In the second embodiment, in the pressurizing mechanism, the piston is pushed out of the cylinder by the urging force of the compression spring provided in the cylinder, and the anode main electrode--the plurality of unit cells--
It presses a combination of cathode main electrodes. The pressurizing mechanism preferably introduces oxygen or hydrogen with any pressure generated during the operation of the water electrolysis cell into the cylinder,
A sequence control mechanism for adjusting the amount of oxygen or hydrogen introduced into the cylinder is provided so that a constant tightening pressure can be obtained.

The reason for selecting the tightening pressure of 4 kgf / cm ² is as follows.

The laminated type electrolytic cell is constructed by laminating a plurality of single cells composed of the above-mentioned several kinds of constituent materials having electric resistance, and fastening a combination of an anode main electrode-a plurality of unit cells-a cathode main electrode from both sides. ing. If the tightening pressure is weaker than 4 kgf / cm ² , the contact between the above-mentioned various components becomes weak (the number of contact points decreases), the electric resistance increases, and the electrolysis voltage increases accordingly, which in turn increases the power consumption. Will end up. Conversely, the tightening pressure is 4
In the case of kgf / cm ² or more, the contact resistance (electrical resistance) is almost constant, and even if the tightening pressure is further increased, the electric resistance cannot be reduced. Further, long-term exposure of the ion-exchange membrane of the cell to high temperature may reduce the membrane thickness and cause deterioration of the membrane, possibly leading to damage to the membrane. Therefore, the tightening pressure is 4 kgf / cm ²
It is good to say

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION Next, the present invention will be specifically described with reference to the drawings.

Example 1 In FIG. 1 showing the whole flow of a solid polymer water electrolyzer, the solid polymer water electrolyzer electrolyzes water using a polymer electrolyte membrane, oxygen is used as an anode and hydrogen is used as a cathode. Water electrolysis tank (21) to generate hydrogen, a hydrogen gas-liquid separator (23) to separate hydrogen and water generated at the cathode of the water electrolysis tank, and oxygen and water generated at the anode of the water electrolysis tank The oxygen gas-liquid separator (24) and the circulation pump (2) that circulates the water to supply water to the water electrolyzer.
A water circulation line (22) including 5) and a hydrogen line (26) provided in the hydrogen gas-liquid separator and equipped with a hydrogen pressure adjusting valve (28).
And the oxygen pressure adjusting valve (2
9) with an oxygen line (27). The hydrogen and oxygen separated by the gas-liquid separator are released to the outside of the system at an arbitrary pressure depending on the opening of the pressure control valves (28) (29). The water is supplied to the water electrolysis device by supplying pure water to the oxygen gas liquid separator (24).

The output of the rectifier (30) is a pressure based on the measured value from the hydrogen pressure detector (31) installed in the hydrogen line (26) according to the preset hydrogen generation amount and hydrogen pressure value. It is adjusted by the PID control of the controller (32).

The water electrolyzer, as described above with reference to FIG. 6, has the anode main electrode (1) and the cathode main electrode (2) arranged at both ends.
And a plurality of unit cells (16) arranged in series between the main electrodes (1) and (2), and an anode main electrode (1) -a plurality of unit cells
(16) -Mainly composed of a tightening device (21) for tightening the combination of the cathode main electrode (2) from both sides.

One cell (16) is the anode side of the bipolar plate (9),
Anode power supply (7), solid polymer electrolyte membrane (3), namely electrode assembly film, cathode power supply (8), backup metal for reinforcing cathode power supply, O-ring for sealing inside and outside of electrolytic cell, inside cell Hydrogen generation area-manifold gasket that seals the oxygen generation area and adjacent bipolar plate (9)
From the cathode side of. Each cell (16) is adjacent to the next cell via an O-ring fitted in the groove provided in the bipolar plate,
The O-ring maintains a seal between the inside of the electrolytic cell and the outside of the electrolytic cell.

The solid polymer electrolyte membrane (3) is an ion exchange membrane.
(4) and catalyst electrode layer plated with precious metal on both sides (5)
(6) consists of and. The number of unit cells is 80 to 600 in a commercial scale electrolytic cell.

When water is supplied into each unit cell (16) from the water supply header (10) at the lower part of the electrolytic cell, it is electrolyzed on the surface of the catalyst electrode layers (5) and (6), and oxygen and cathode on the anode side. Hydrogen is generated on each side. The generated oxygen and hydrogen reach the anode side and the cathode side of the bipolar plate (9) through the porous power feeders (7) and (8), respectively, and further through the vertical flow paths provided in the bipolar plate. Reach the top of the electrolyzer, oxygen header on top of the electrolyzer (11)
And is discharged to the outside through hydrogen (12).

The tightening device (21), as shown in FIG.
Anode main electrode (1) -Multiple unit cells (16) -Cathode main electrode (2)
The combination of the flange (33) arranged on one side,
The pressure mechanism (34) arranged on the other side uniformly tightens the pressure. The pressurization mechanism (34) is a nozzle for introducing the fluid for compression.
(37) having a discharge nozzle (36) and a piston arranged in the cylinder (37) via an O-ring (38)
It consists of (39) and. The flange (33) and cylinder (37) are bolted
Connected with (14) and nut (15).

As shown in FIG. 1, the tightening device (21) includes a hydrogen pressure detector (31) during operation of the solid polymer water electrolyzer.
In order to apply to the pressurization mechanism (34) a pressure that is always higher than the hydrogen pressure that is constantly detected by the pressurizing mechanism (4 kgf / cm ² ), the compression fluid introduction nozzle (3
5) and a sequence control mechanism for adjusting the fluid flow rate adjusting valves (41, 42) respectively connected to the discharge nozzle (36). As a result, a constant tightening pressure (4 kgf / cm ² ) is always ensured regardless of any operating pressure or pressure fluctuation, regardless of the operating pressure and pressure fluctuation, and stable electrolytic performance is exhibited.

More specifically, the differential pressure regulator (44) detects the difference between the operating pressure detected by the hydrogen pressure detector (31), that is, the hydrogen pressure and the pressure detected by the tightening pressure detector (43). Then, sequence control is performed so that the pressure applied to the pressurizing mechanism (34) is increased by the tightening pressure (4 kgf / cm ² ) above the operating pressure (or any pressure when pressure fluctuation occurs). . The tightening pressure of 4 kgf / cm ² is not limited, and there is an optimum value depending on the thickness of the solid polymer electrolyte membrane and the like, so it may be set to a set value according to that value.

Embodiment 3 In this embodiment, as shown in FIGS. 3 and 4, the tightening device (21) includes an anode main electrode (1) -a plurality of unit cells (16) -a cathode main electrode (2). The combination is uniformly tightened by the flange (33) arranged on one side of the combination and the spring type pressure mechanism (53) arranged on the other side. The pressurizing mechanism (53) includes a cylinder (45) having a fluid introduction nozzle (48) and a cylinder (45).
A piston (47) arranged through an O-ring (49) therein, and a plurality of compression springs (46) interposed between the bottom wall of the cylinder (45) and the piston (47), The urging force of the compression spring (46) pushes the piston (47) out of the cylinder (45) and presses the combination of the anode main electrode-a plurality of unit cells-the cathode main electrode. The compression spring (46) is placed in a spring accommodating portion (51) provided on the rear end surface of the piston (47). Flange
(33) and the cylinder (45) are connected by a bolt (14) and a nut (15).

A nozzle for introducing oxygen having an arbitrary pressure generated during the operation of the solid polymer water electrolyzer through a line (52)
A sequence control mechanism is provided to adjust the amount of oxygen or hydrogen introduced into the cylinder so that a constant tightening pressure can be obtained by introducing it into the cylinder (45) via (48). As a result, stable electrolysis performance is exhibited under a certain absolute tightening pressure regardless of the operating pressure or the pressure fluctuation, regardless of the operating pressure or the pressure fluctuation.

The other structure is the same as that of the first embodiment.

In the above structure, oxygen or hydrogen having an arbitrary pressure of 10 kgf / cm ² or less specified by the high pressure gas control method is introduced into the flange. By properly selecting the type and number of compression springs, the tightening pressure can be always maintained at 4 kgf / cm ² G. By using this method, stable electrolysis performance can be exhibited against an arbitrary operating pressure or pressure fluctuation of 10 kgf / cm ² or less. In addition, stable electrolytic performance can be achieved with an inexpensive and simple system without separately preparing fluid and power for operating the cylinder.

The O-ring (49) keeps the pressure inside the cylinder so that the gas introduced into the cylinder does not leak to the outside.
It is arranged in the O-ring groove on the circumferential surface of the piston.

The combination of the anode main electrode (1) -a plurality of unit cells (16) -cathode main electrode (2) is equivalent to a tightening pressure of 4 kgf / cm ² by the flange (33) and the pressurizing mechanism (53). Appropriate 4kgf / c by compressing the distance
A tightening pressure state of m ² can be obtained. Naturally, the spring length is set so that the rear end surface of the piston does not contact the facing surface of the cylinder even in a tightening pressure state of 4 kgf / cm ² . Further, a stopper (50) is provided at the end of the cylinder so that the piston does not jump out of the cylinder by the urging force of the spring when tightening. By this method, stable water electrolysis can be performed at an arbitrary pressure of 10 kgf / cm ² or less. Further, even when the pressure fluctuates during operation, electrolytic operation can be performed while exhibiting stable electrolytic performance.

[0031]

According to the solid polymer type water electrolysis cell of the present invention, when operating the solid polymer type water electrolysis cell at an arbitrary operating pressure, or changing the operating pressure to an arbitrary pressure. If desired, the operation can be performed under a constant absolute tightening pressure irrespective of the operating pressure and the pressure fluctuation, and stable electrolysis performance can be easily demonstrated.

[Brief description of drawings]

FIG. 1 is a schematic vertical sectional view showing a water electrolysis device of Example 1.

FIG. 2 is a schematic vertical sectional view showing the tightening device of the first embodiment.

FIG. 3 is a schematic vertical sectional view showing a water electrolysis device of Example 2.

FIG. 4 is a schematic vertical sectional view showing a tightening device according to a second embodiment.

FIG. 5 is a graph showing the relationship between tightening pressure and electrolytic pressure.

FIG. 6 is a schematic vertical sectional view showing a laminated water electrolysis device.

[Explanation of symbols]

(1) Anode main electrode, (2) Cathode main electrode, (14) Bolt, (15) Nut, (16) Unit cell, (21) Tightening device, (31) Hydrogen pressure detector, (33) Flange, ( 34) pressurizing mechanism, (35) introduction nozzle, (36) discharge nozzle, (37) cylinder, (39) piston, (4
1) (42) Fluid flow control valve, (43) Tightening pressure detector, (44)
Differential pressure regulator, (45) cylinder, (46) compression spring, (47) piston, (48) introduction nozzle, (53) spring type pressure mechanism

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Hitoshi Ojira             1-89 Minami Kohoku 1-89, Suminoe-ku, Osaka             Standing Shipbuilding Co., Ltd. (72) Inventor Hiroshi Tatsumi             1-89 Minami Kohoku 1-89, Suminoe-ku, Osaka             Standing Shipbuilding Co., Ltd. (72) Inventor Shogo Hamada             1-89 Minami Kohoku 1-89, Suminoe-ku, Osaka             Standing Shipbuilding Co., Ltd. (72) Inventor Matsunaga Victory             1-89 Minami Kohoku 1-89, Suminoe-ku, Osaka             Standing Shipbuilding Co., Ltd. (72) Inventor Daisuke Tamakoshi             1-89 Minami Kohoku 1-89, Suminoe-ku, Osaka             Standing Shipbuilding Co., Ltd. F-term (reference) 4K021 AA01 BA02 BB04 BC09 CA01                       CA08 CA10 CA11 CA13 DB04                       DB43 DB53 DC01 DC03

Claims (5)

[Claims] 1. An anode main electrode and a cathode main electrode arranged at both ends, a plurality of unit cells arranged in series between these main electrodes, and an anode main electrode-a plurality of unit cells-a cathode main electrode. A polymer electrolyte water electrolysis cell mainly composed of a tightening device for tightening the combination from both sides, wherein the tightening device has a combination of an anode main electrode-a plurality of unit cells-a cathode main electrode arranged on one side thereof. A tightening device in a solid polymer type water electrolysis tank, which is tightened by a flange and a pressure mechanism arranged on the other side. 2. A pressurizing mechanism, wherein a piston is extruded from the cylinder by a pressure applied to the pressurizing mechanism by introducing a fluid into the cylinder, and a combination of an anode main electrode, a plurality of unit cells and a cathode main electrode is formed. Claim 1 which presses.
The tightening device in the solid polymer type water electrolyzer according to. 3. The pressurizing mechanism detects any pressure or pressure fluctuation of oxygen or hydrogen generated during the operation of the water electrolysis cell, and detects the pressure applied to the pressurizing mechanism by introducing the fluid into the cylinder. However, a sequence control mechanism that detects the difference between these two pressures and adjusts the amount of fluid introduced into the cylinder so that the latter detected pressure becomes greater than the former detected pressure by the tightening pressure, The tightening device for a solid polymer water electrolyzer according to claim 2. 4. The pressurizing mechanism presses a combination of an anode main electrode, a plurality of unit cells, and a cathode main electrode by pushing a piston out of the cylinder by the urging force of a compression spring provided in the cylinder. The tightening device for a solid polymer type water electrolyzer according to claim 1. 5. The pressurizing mechanism introduces oxygen or hydrogen having an arbitrary pressure generated during the operation of the water electrolysis cell into the cylinder so that a constant tightening pressure can be obtained. Alternatively, the tightening device in the solid polymer type water electrolyzer according to claim 4, further comprising a sequence control mechanism for adjusting the amount of hydrogen introduced.