JP3991147B2 - Solid polymer water electrolyzer - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to a water electrolytic cell using a polymer electrolyte membrane.
[0002]
[Prior art]
Conventionally, the structure of a water electrolysis cell in the case of producing hydrogen and oxygen by water electrolysis using a polymer electrolyte membrane is as follows. As shown in FIG. 6, the anode main electrode (1) and the cathode main electrode (2) It is mainly composed of a plurality of unit cells arranged in series between the main electrodes (1) and (2) and a fastening flange (6) arranged outside the main electrodes (1) and (2). One cell consists of a bipolar plate (9), a porous anode feeder (7), an electrode assembly membrane (3), a porous cathode feeder (8) and the cathode of the adjacent bipolar plate (9). The electrode assembly membrane (3) is composed of an ion exchange membrane (4) that is long in the vertical direction and a catalyst electrode layer (5) provided at the center of both surfaces thereof.
[0003]
In this polymer-type water electrolyzer, the water supplied from the water supply header (10) at the bottom of the electrolyzer reaches the electrode assembly film (3) through the anode power feeder (7), and the electric power applied here As a result, water undergoes an electrolysis reaction, and in each unit cell, oxygen is generated on the surface of the catalyst electrode layer (5) on the anode side and hydrogen is generated on the cathode side. The generated oxygen passes through the anode power feeder (7), rises with the unreacted water in the vertical flow path provided on the anode side of the bipolar plate (9), and is discharged to the oxygen header (11). In addition, the generated hydrogen passes through the cathode feeder (8), passes through the vertical flow path provided on the cathode side of the bipolar plate (9), reaches the upper part of the electrolytic cell, and is discharged to the hydrogen header (12). The
[0004]
The anode feeder (7) and the cathode feeder (8) are the same size as the electrical current-carrying part (9a) that also serves as the water, oxygen, and hydrogen flow paths provided on the bipolar plate (9), and the electrodes The ion exchange membrane (4) of the assembly membrane (3) is the same size as the bipolar plate (9), and the catalyst electrode layer (5) of the electrode assembly membrane (3) is the electrical conducting part of the bipolar plate (9). Same size as (9a).
Water passage holes (13) and (16) are respectively provided at the lower ends of the bipolar plate (9) and the electrode assembly membrane (3), and oxygen passage holes (14), (17) and Hydrogen passage holes (15) and (18) are respectively provided. The corresponding through-holes (13), (16), (14), (17), (15), and (18) of the bipolar plate (9) and the electrode assembly film (3) are the hydrogen generation region-oxygen inside the cell. A short cylindrical seal rubber (19A) that seals the generation region or a porous gasket (19B) that allows water, hydrogen, or oxygen to pass through the region.
[0005]
As shown in FIGS. 7 and 8, the periphery of the bipolar plate (9) is substantially square when viewed from the front, and the bottom surface is in contact with the anode side surface of the electrode assembly film (3). An O-ring fitting groove (21) is provided, and an O-ring (20) fitted in the groove (21) causes a peripheral portion of the bipolar plate (9) and a peripheral portion of the electrode assembly film (3) to That is, between the inside and outside of the electrolytic cell is sealed.
[0006]
In addition, as shown in FIG. 9, a bipolar plate (9) having passage holes (13), (14), (15), (16), (17), (18) (shown as water passage holes (13), (16)). Between the upper and lower edges of the electrode assembly film and the upper and lower edges of the electrode assembly film (3), only the sealing rubber (19A) or the porous gasket (19B) is interposed, and the anode feeder (7) and the cathode feeder The upper and lower edges of the body (8) are not located in this part.
[0007]
[Problems to be solved by the invention]
In the conventional polymer-type water electrolyzer, the electrode assembly film (3) is damaged near the boundary between the anode feeder (7) and the cathode feeder (8) (near the portion indicated by A in FIG. 8). In addition, there is a problem that the electrode assembly membrane (3) is damaged even in the vicinity of the seal rubber (19A) (in the vicinity of the portion indicated by B in FIG. 9) or the porous gasket (19B), and the improvement Has become an issue.
[0008]
The present invention has been devised to solve the above-described problems. On the space side where oxygen is generated, the gas pressure is higher than the space where hydrogen is generated because water circulates. Therefore, paying attention to the fact that the electrode assembly film is pushed from the oxygen side to the hydrogen side, and the portion of the electrode assembly film that contacts the edge of the cathode power feeder tends to be damaged, the electrode assembly The object is to achieve a long lifetime of the film.
[0009]
[Means for Solving the Problems]
A polymer-type water electrolyzer according to a first invention includes an anode main electrode and a cathode main electrode, and a plurality of unit cells arranged in series between the main electrodes, each cell being a bipolar plate An anode feeder, an electrode assembly film made of a solid polymer electrolyte membrane, a cathode feeder, and a peripheral portion of the bipolar plate fitted in an O-ring insertion groove provided on the peripheral edge of the bipolar plate; in the high-molecular water electrolyzer that has a O-ring to seal between the periphery of the electrode assembly film, as the bottom surface of the O-ring fitting groove is in contact with the anode side of the electrode assembly film made which have left and right edges of the anode current collector is in contact with the inner peripheral edge portion of the O-ring fitting groove, and is characterized in that the lateral edges of the cathode current collector are arranged so that contact with the O-ring .
[0010]
According to the polymer-type water electrolyzer of the first invention, the pressure applied from the oxygen side to the hydrogen side at the inner peripheral edge of the O-ring insertion groove is received by the left and right edges of the anode feeder and the cathode feeder. , Partial elongation of the electrode assembly film is suppressed.
[0011]
Then, the bottom surface of the O-ring fitting groove has been in contact with the anode side of the electrode assembly film, left and right edges of the anode current collector is in contact with the inner peripheral edge portion of the O-ring fitting groove, the cathode current collector Since the right and left edge portions of the power supply are in contact with the O-ring, it can be dealt with only by changing the dimensions of the power feeder, and the manufacturing effort does not increase.
[0012]
In the above, a groove part may be provided along the inner periphery of the O-ring, and the right and left edge parts of the cathode power supply body may be fitted into the groove part. If it does in this way, the edge of a cathode electric power feeder will be covered with an O-ring, and it will be reliably prevented that the edge of a cathode electric power feeder hits an electrode assembly film.
[0013]
The cathode power supply body preferably has a two-layer structure of a power supply layer and a reinforcing layer. In this case, it is preferable that the width of the groove provided along the inner periphery of the O-ring is made to correspond to the thickness of the reinforcing layer, and only the left and right edge portions of the reinforcing layer are fitted into the groove.
[0014]
A polymer-type water electrolyzer according to a second invention comprises an anode main electrode and a cathode main electrode, and a plurality of unit cells arranged in series between the main electrodes, each cell being a bipolar plate An anode feeder, an electrode assembly film made of a solid polymer electrolyte membrane, and a cathode feeder, with water passage holes at the lower edge of the bipolar plate and electrode assembly membrane, In a polymer electrolyte water electrolysis cell in which holes for passing hydrogen and oxygen are provided, and the corresponding through holes are communicated with each other by a short cylindrical communicating member, the cathode feeder is connected to the upper and lower edges of the electrode assembly film. The upper and lower edge portions are provided with a communication member insertion hole having a diameter larger than the inner diameter of the communication member and smaller than the outer diameter, and the communication member has a peripheral edge of the communication member insertion hole. It is characterized in that a notch for receiving the part is provided.
[0015]
The communicating member refers to a seal rubber that communicates between the corresponding passage holes in a state where the hydrogen generation region-oxygen generation region inside the cell is sealed, and communication between the corresponding passage holes in a state where water, hydrogen, or oxygen is passed in the region. Both porous gaskets to be included.
[0016]
According to the polymer-type water electrolyzer of the second invention, the pressure applied from the oxygen side to the hydrogen side in the vicinity of the water, hydrogen and oxygen passage holes is received by the connecting member insertion hole edge of the cathode power supply. The elongation leading to the damage of the electrode assembly film is suppressed.
[0017]
The first invention and the second invention may be used alone or in combination.
[0018]
It is preferable that the anode power supply body and the cathode power supply body are made of a titanium fiber sintered body plated with platinum. In this way, the titanium fiber layer is in contact with the electrode assembly film. As a result, the current flows uniformly, and the electrode assembly film can be prevented from being damaged, and further, hydrogen embrittlement is avoided by platinum plating. be able to. Further, the anode power feeding body may be made of a titanium fiber sintered body that is platinum-plated, and the cathode power feeding body may be made of a carbon fiber sintered body.
[0019]
【Example】
Examples of the present invention will be described below. In this specification, the top and bottom refer to the top and bottom of FIG. 1, and the left and right also refer to the left and right of FIG.
[0020]
Example 1
The principal part of Example 1 is shown in FIGS. FIG. 1 corresponds to FIG. 7 of a conventional polymer-type water electrolyzer, and FIGS. 2 and 3 correspond to FIGS. 8 and 9 respectively. In this embodiment, the configurations different from those shown in FIGS. 6 to 9 shown in the prior art are the anode power supply (31), the cathode power supply (32), and the seal rubber (36). The same thing as the conventional one shown in FIGS. 6 to 9 is used.
[0021]
As shown in FIGS. 1 and 2, the anode feeder (31) has a slightly larger left-right width than the conventional anode feeder (7), and is otherwise the same as the conventional one. Accordingly, the left and right edge portions (31a) of the anode power feeding body (31) are in contact with the inner peripheral edge portion (21a) of the O-ring fitting groove (21).
[0022]
Further, the cathode power supply (32) is larger in both lateral width and vertical height than the conventional cathode power supply (8), and is otherwise the same as the conventional one. The left and right width of the cathode power supply (32) is made larger than the left and right width of the anode power supply (31), so that the left and right edge portions (32a) of the cathode power supply (32) are O-ring fitting grooves. The inner periphery (21a) of (21) and the inner periphery of the O-ring (20) are in contact with each other.
[0023]
As can be seen from FIG. 2, the pressure applied from the oxygen side to the hydrogen side at the inner peripheral edge of the O-ring insertion groove (21) is determined by the left and right edges (31a) of the anode power supply (31) and the cathode power supply (32). (32a), the partial elongation of the electrode assembly film (3) can be suppressed. Therefore, it is possible to prevent early breakage of the electrode assembly film (3) that has occurred in the vicinity of the portion indicated by A in FIG. 8, and to prolong the life of the electrode assembly film (3).
[0024]
As shown in FIG. 1 and FIG. 3, the vertical height of the cathode power supply (32) is such that the vertical edge (32b) is positioned in the vicinity of the inner peripheral edge (21a) of the O-ring fitting groove (21). It has been made bigger. Therefore, the upper and lower edges (32b) of the cathode power feeder (32) are provided with water passage holes (13), (16), oxygen passage holes (14), (17), and hydrogen passage holes (15), (18), respectively. The upper and lower edges of the bipolar plate (9) and the electrode assembly film (3) are opposed to the upper and lower edges of the electrode assembly film (3). Seal rubber insertion holes (33) are provided at positions corresponding to the respective through holes (13), (16), (14), (17), (15), and (18) at the upper and lower edges (32b) of the cathode power feeder (32). Is provided.
[0025]
FIG. 3 shows the lower header portion through which water passes. As shown in FIG. 3, the diameter of the seal rubber insertion hole (33) in the lower edge portion (32b) of the cathode power supply body (32) is The bipolar plate (9) and the electrode assembly membrane (3) are formed larger in diameter than the water passage holes (13) and (16). The short cylindrical seal rubber (36) that seals the hydrogen generation region-oxygen generation region inside the cell has an inner diameter of each through hole (13) (16) of the bipolar plate (9) and the electrode assembly membrane (3). ), The outer diameter is larger than the water passage hole (33) of the cathode power feeder (32), and on the electrode assembly film (3) side of the outer periphery thereof, the cathode power feeder (32) A notch (36a) for receiving the peripheral edge of the seal rubber insertion hole (33) is provided. Although not shown, the upper header portion through which oxygen and hydrogen pass has the same configuration. According to the configuration of FIG. 3, the pressure applied from the oxygen side to the hydrogen side in the vicinity of the water passage holes (13) and (16), the oxygen passage holes (14) and (17), and the hydrogen passage holes (15 and 18) It is received by the peripheral edge portion of the seal rubber insertion hole (33) provided in the upper and lower edge portions (32b) of the body (32), and the elongation leading to the damage of the electrode assembly film (3) is suppressed. Accordingly, it is possible to prevent early breakage of the electrode assembly film (3) that has occurred in the vicinity of the portion indicated by B in FIG. 9, and to prolong the life of the electrode assembly film (3).
[0026]
Example 2
The principal part of Example 2 is shown in FIG. This figure corresponds to FIG. 2 of the first embodiment. In the present embodiment, the same components as those in the first embodiment are denoted by the same reference numerals and description thereof is omitted.
[0027]
As shown in the figure, the cathode power supply (42) has a larger left-right width than the cathode power supply (32) of Example 1, and correspondingly, the O-ring (40) An L-shaped groove (40a) into which the left and right edge portions (42a) of the cathode power supply body (42) are fitted is provided along the inner periphery.
[0028]
According to the configuration of the second embodiment, the pressure applied from the oxygen side to the hydrogen side at the inner peripheral edge of the O-ring fitting groove (21) is changed to the left and right edges (31a) of the anode feeder (31) and the cathode feeder (42). Since (42a) is received, partial elongation of the electrode assembly film (3) is suppressed. Since the left and right edge portions (42a) of the cathode power supply (42) are received by the groove portion (40a), it is ensured that the edge of the cathode power supply (42) hits the electrode assembly film (3). It is prevented. Therefore, it is possible to prevent early breakage of the electrode assembly film (3) that has occurred in the vicinity of the portion indicated by A in FIG. 8, and to prolong the life of the electrode assembly film (3).
[0029]
Example 3
In the polymer-type water electrolyzers of Example 1 and Example 2, the cathode power supply (32) (42) is a single layer, but the cathode power supply (52) may be a double layer.
[0030]
FIG. 5 shows a main part of the third embodiment. This figure corresponds to FIG. 2 of the first embodiment and FIG. 4 of the first embodiment. In this embodiment, the same components as those of the first or second embodiment are denoted by the same reference numerals, and description thereof is omitted.
[0031]
As shown in the figure, the cathode power feeder (52) has a two-layer structure of a power feeding layer (53) and a reinforcing layer (54). The reinforcing layer (54) is formed such that its left-right width is slightly larger than the left-right width of the power feeding layer (53). The groove (50a) provided along the inner periphery of the O-ring (50) is U-shaped and its width corresponds to the thickness of the reinforcing layer (54). Only the left and right edge portions (54a) are fitted into the groove portions (50a).
[0032]
According to the configuration of Example 3, the pressure applied from the oxygen side to the hydrogen side at the inner peripheral edge of the O-ring fitting groove (21) is changed to the left and right edges (31a) of the anode power supply (31) and the cathode power supply (52). Since (54a) is received, partial elongation of the electrode assembly film is suppressed. Since the cathode power supply (52) has a two-layer structure having a reinforcing layer (back metal) (54), the durability of the cathode power supply (52) itself is improved, and the reinforcing layer (54 ), The right and left edge portions (54a) are received by the groove portion (50a), so that the electrode assembly film (3) is reliably prevented from hitting the edge of the cathode power supply body (52) and the power supply layer ( Since the left and right edge portions (53a) of 53) are received by the left and right edge portions (54a) of the reinforcing layer (54), the movement thereof is further suppressed. Therefore, it is possible to prevent early breakage of the electrode assembly film (3) that has occurred in the vicinity of the portion indicated by A in FIG. 8, and to prolong the life of the electrode assembly film (3).
[0033]
About each said Example, when the durability was investigated by the use similar to the conventional polymer-type water electrolyzer, 90% of the conventional thing was damaged in 4000 hours, The thing of each said Example Was not damaged even after 8000 hours, and the durability was greatly improved.
[0034]
In the above, the O-ring fitting groove (21) of the bipolar plate (9) can be installed vertically in addition to installing the water electrolysis tank horizontally. Further, according to this water electrolyzer, it is possible to cause a reaction reverse to the above, that is, a reaction for generating water and energy from hydrogen and oxygen. In the above description, the seal rubber (first communication member) indicated by (19A) in FIG. 6 is described. Of course, the present invention can be applied to the porous gasket (second communication member) indicated by (19B) in FIG. Good.
[0035]
【The invention's effect】
According to the polymer-type water electrolyzer of the first invention, the bottom surface of the O-ring insertion groove is in contact with the surface on the anode side of the electrode assembly film, and the left and right edges of the anode feeder are O-ring fitting. against the inner periphery of the write groove, since the left and right edges of the cathode current collector are arranged so that contact with the O-ring, the anode feeding pressure on the hydrogen side of the oxygen side in the inner peripheral portion of the O-ring fitting groove Since the left and right edge portions of the body and the cathode power supply body are received, partial elongation of the electrode assembly film is suppressed, whereby the electrode assembly film that has occurred near the inner peripheral edge of the O-ring insertion groove Early damage can be prevented, and the durability of the water electrolyzer can be greatly improved.
[0036]
According to the polymer water electrolyzer of the second invention, the pressure applied from the oxygen side to the hydrogen side in the vicinity of the water passage hole, the oxygen passage hole and the hydrogen passage hole is received by the edge of the communicating member insertion hole of the cathode power feeder. Therefore, the elongation leading to breakage of the electrode assembly membrane can be suppressed, thereby preventing early failure of the electrode assembly membrane in the vicinity of water, hydrogen and oxygen passage holes. The durability of can be greatly improved.
[Brief description of the drawings]
FIG. 1 is a front view showing individual components of one cell of a polymer-type water electrolyzer according to the present invention.
FIG. 2 is a partial sectional view showing Example 1 of the water electrolyzer according to the first invention, and corresponds to FIG. 8 showing a conventional polymer-type water electrolyzer.
FIG. 3 is a partial cross-sectional view showing Example 1 of the water electrolyzer according to the second invention and corresponds to FIG. 9 of a conventional polymer-type water electrolyzer.
FIG. 4 is a partial cross-sectional view corresponding to FIG. 2 of Example 2 of the polymer-type water electrolyzer of the first invention.
FIG. 5 is a partial cross-sectional view corresponding to FIG. 2 of Example 3 of the polymer type water electrolyzer according to the first invention.
FIG. 6 is an exploded perspective view showing a disassembled state of a conventional polymer type water electrolyzer.
FIG. 7 is a front view showing components of one cell individually.
FIG. 8 is a partial cross-sectional view showing a portion that is easily damaged in a conventional water electrolyzer.
FIG. 9 is a partial cross-sectional view showing another part that is easily damaged in a conventional water electrolyzer.
[Explanation of symbols]
(1) Anode main electrode
(2) Cathode main electrode
(3) Electrode assembly membrane
(9) Bipolar plate
(20) (40) (50) O-ring
(40a) (50a) Groove
(21) O-ring insertion groove
(21a) Inner peripheral edge
(31) Anode feeder
(31a) Left and right edges
(32) (42) (52) Cathode feeder
(32a) (42a) (53a) (54a) Left and right edges
(32b) Upper and lower edges
(36) Seal rubber (communication member)
(36a) Notch
(53) Feed layer
(54) Reinforcing layer
(13) (16) Water passage hole
(14) (17) Oxygen passage hole
(15) (18) Hydrogen passage hole

Claims (8)

An anode main electrode (1) and a cathode main electrode (2), and a plurality of unit cells arranged in series between these main electrodes (1) (2), each cell is a bipolar plate ( 9), an anode feeder (31), an electrode assembly film (3) made of a solid polymer electrolyte membrane, a cathode feeder (32), and an O-ring provided on the periphery of the bipolar plate (9) O-rings (20), (40) and (50) which are fitted in the fitting grooves (21) and seal between the peripheral edge of the bipolar plate (9) and the peripheral edge of the electrode assembly film (3). in the high-molecular water electrolyzer it is,
O-ring fitting the bottom of the groove (21) have been made in contact with the anode side of the electrode assembly film (3), right and left edges (31a) of O-ring fitting groove of the anode current collector (31) and contacting the inner peripheral edge portion of (21) (21a), against the cathode current collector (32) (42) right and left edges of the (52) (32a) (42a) (53a) (54a) is O-ring (20) A polymer type water electrolyzer characterized in that Grooves (40a) and (50a) are provided along the inner periphery of the O-ring (40) and (50), and left and right edges (42a) of the cathode power feeders (42) and (52) are provided in the grooves (40a and 50a). (54a) polymer water electrolyzer according to claim 1, wherein the is fitted. Cathode current collector (52), a feeding layer (53) and the reinforcing layer (54) and the polymer water electrolyzer of claim 1 Symbol mounting, characterized in that it is a two-layer structure. The cathode feeder (52) has a two-layer structure of a feeding layer (53) and a reinforcing layer (54), and the width of the groove (50a) provided along the inner periphery of the O-ring (50) is 3. The polymer according to claim 2, wherein only the left and right edge portions (54a) of the reinforcing layer (54) are fitted into the groove portion (50a) in correspondence with the thickness of the reinforcing layer (54). Type water electrolyzer. Water passage holes (13), (16) at the lower edge of the bipolar plate (9) and electrode assembly membrane (3), and passage holes for hydrogen and oxygen at the upper edge (14), (15), (17) (18) is provided, and the corresponding through holes (13), (14), (15), (16), (17), and (18) are communicated with each other by a short cylindrical communication member (36), (32) has upper and lower edges (32b) that contact the upper and lower edges of the electrode assembly film (3), and the upper and lower edges (32b) are larger than the inner diameter of the communication member (36) and have an outer diameter. A communication member insertion hole (33) having a smaller diameter is provided, and an annular notch (36a) for accommodating the peripheral portion of the communication member insertion hole (33) is provided on the outer peripheral portion of the communication member (36). polymer type water electrolysis cell as claimed one of claims 1-4, characterized in that there. An anode main electrode (1) and a cathode main electrode (2), and a plurality of unit cells arranged in series between these main electrodes (1) (2), each cell is a bipolar plate ( 9), an anode feeder (31), an electrode assembly film (3) made of a solid polymer electrolyte membrane, and a cathode feeder (32), and a bipolar plate (9) and an electrode assembly membrane (3) Water passage holes (13) and (16) are provided at the lower edge portion, and oxygen passage holes (14) and (15) and hydrogen passage holes (17) and (18) are provided at the upper edge portion. in passing hole (13) (14) (15) (16) (17) (18) high-molecular water electrolyzer that have communicated with each other by the short cylindrical communication member (36),
The cathode power supply (32) has upper and lower edges (32b) that contact the upper and lower edges of the electrode assembly film (3), and the upper and lower edges (32b) are larger than the inner diameter of the communication member (36). In addition, a communication member insertion hole (33) having a diameter smaller than the outer diameter is provided, and an annular notch (36a) for accommodating the peripheral portion of the communication member insertion hole (33) is provided on the outer peripheral portion of the communication member (36). A polymer type water electrolyzer characterized by being provided. Anode current collector (31) and a cathode current collector (32) (42) (52), one of claims 1-6, characterized in that it consists of those respectively platinized sintered body of titanium fibers The polymer type water electrolyzer described. The anode power feeding body (31) is made of a platinum-plated titanium fiber sintered body, and the cathode power feeding bodies (32), (42) and (52) are made of a carbon fiber sintered body. polymer type water electrolysis cell as claimed one of claims 1 to 6.

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