Bipolar plate with double-sided gasket, water electrolysis device provided with bipolar plate with double-sided gasket, method for manufacturing bipolar plate with double-sided gasket, and method for manufacturing water electrolysis device provided with bipolar plate with double-sided gasket

Abstract

The present invention addresses the problem of providing a bipolar plate with a double-sided gasket, which has high productivity.　This bipolar plate (2) comprises a bipolar plate main body (20) and a gasket (5). A front-side gasket (5U) of the gasket (5) is provided with a front-side first seal part (52U) and a front-side second seal part (53U). A rear-side gasket (5D) of the gasket (5) is provided with a rear-side first seal part (52D) and a rear-side second seal part (53D). On the front surface (20U) side of the bipolar plate main body (20), the front-side first seal part (52U) surrounds first manifolds (20La, 20Rb) and a front-side flow path area (21U), and the front-side second seal part (53U) surrounds second manifolds (20Lb, 20Ra). On the rear surface (20D) side of the bipolar plate main body (20), the rear-side first seal part (52D) surrounds the first manifolds (20La, 20Rb), and the rear-side second seal part (53D) surrounds the second manifolds (20Lb, 20Ra) and a rear-side flow path area (21D).

Description

Bipolar plate with double-sided gaskets, water electrolysis device comprising the bipolar plate with double-sided gaskets, manufacturing method of the bipolar plate with double-sided gaskets, and manufacturing method of the water electrolysis device comprising the bipolar plate with double-sided gaskets

[0001] The present disclosure relates to a bipolar plate with double-sided gaskets used in a water electrolysis device for producing hydrogen by electrolyzing water, a water electrolysis device comprising the bipolar plate with double-sided gaskets, a manufacturing method of the bipolar plate with double-sided gaskets, and a manufacturing method of the water electrolysis device comprising the bipolar plate with double-sided gaskets.

[0002] The water electrolysis device of Patent Document 1 includes a laminate of a plurality of separators and a plurality of electrolytic cells. A pair of through-holes penetrating the separator in the front and back directions are provided in the separator. Through the pair of through-holes, a pair of adjacent electrolytic cells sandwiching the separator communicate with each other. Gaskets separate from the separator are respectively fitted on the front and back surfaces of the separator. Each of the pair of gaskets has an annular shape. When viewed from the front and back direction (lamination direction), the pair of through-holes are accommodated inside the ring of the gasket.

[0003] International Publication No. 2024 / 106305 pamphlet

[0004] Although not disclosed or suggested in Patent Document 1, it is assumed that a flow path for anode-side fluid is defined on one of the front and back surfaces of the bipolar plate with double-sided gaskets, and a flow path for cathode-side fluid is defined on the other surface. In this case, it is necessary to devise the shape and arrangement of both flow paths. For this reason, the structure of the bipolar plate with double-sided gaskets becomes complicated, and as a result, the productivity of the bipolar plate with double-sided gaskets decreases.

[0005] Therefore, an object of the present disclosure is to provide a bipolar plate with double-sided gaskets having high productivity. Another object of the present disclosure is to provide a water electrolysis device comprising the bipolar plate with double-sided gaskets, a manufacturing method of the bipolar plate with double-sided gaskets, and a manufacturing method of the water electrolysis device comprising the bipolar plate with double-sided gaskets.

[0006] (1) In order to solve the above problems, the double-sided gasketed bipolar plate of the present disclosure is a press-formed metal plate having a first manifold through which a first fluid on the anode side flows and a second manifold through which a second fluid on the cathode side flows, and having a front flow path area through which the first fluid flows and a front arrangement portion on the surface, and a back flow path area through which the second fluid flows and a back arrangement portion on the back surface, and a gasket having an elastomer front gasket arranged in the front arrangement portion and an elastomer back gasket arranged in the back arrangement portion, wherein the front gasket has a front first seal portion surrounding the first manifold and the front flow path area and a front second seal portion surrounding the second manifold, and the back gasket has a back first seal portion surrounding the first manifold and a back second seal portion surrounding the second manifold and the back flow path area.

[0007] The bipolar plate body in this configuration is a press-formed metal plate. Press forming allows for the simultaneous formation and placement of the front channel area and front mounting section, and the back channel area and back mounting section, onto the bipolar plate body. This improves the productivity of the bipolar plate body, and consequently, the bipolar plate with double-sided gaskets.

[0008] Furthermore, the front and back surfaces of the bipolar plate body exhibit a shape that is symmetrical to one another. For example, the convex parts of the front surface correspond to the concave parts of the back surface, and the concave parts of the front surface correspond to the convex parts of the back surface. Therefore, the front channel area and the back channel area can have shapes that are inverted relative to each other in the front-to-back direction. Similarly, the front-side configuration part and the back-side configuration part can have shapes that are inverted relative to each other in the front-to-back direction.

[0009] Furthermore, this configuration allows for the securing of both the front and back flow path areas with a single bipolar plate body. Therefore, compared to cases where separate plate members are used for the front and back flow path areas, the number of parts in the water electrolysis device can be reduced. Additionally, the reduction in the number of parts reduces the assembly time required for the water electrolysis device.

[0010] (1-1) In the configuration of (1) above, the shape of the front gasket and the shape of the back gasket when inverted in the front-to-back direction may be the same as those of the front gasket when viewed from the front-to-back direction.

[0011] According to this configuration, in a single bipolar plate with double-sided gaskets, the front gasket and the back gasket have reversible symmetrical shapes (they match when stacked after being reversed (rotated 180°) in the front-back direction). Therefore, the shape of the front gasket and the shape of the back gasket can be made common. Consequently, the productivity of bipolar plates with double-sided gaskets can be improved.

[0012] (1-2) In the configuration of (1-1) above, the water electrolysis apparatus comprises a laminate in which the double-sided gasketed bipolar plates and water electrolysis members are alternately stacked in the front-back direction, and in the laminate, any of the water electrolysis members is designated as a reference water electrolysis member, the double-sided gasketed bipolar plate stacked adjacent to the front side of the reference water electrolysis member is designated as a front-side bipolar plate, and the double-sided gasketed bipolar plate stacked adjacent to the back side of the reference water electrolysis member is designated as a back-side bipolar plate, and the front-side bipolar plate and the back-side bipolar plate are stacked in reverse in the front-back direction.

[0013] In this configuration, the front dipole plate and the back dipole plate are stacked inverted in the front-to-back direction. Here, in the front dipole plate, the front gasket and the back gasket have inverted symmetrical shapes relative to each other. Similarly, in the back dipole plate, the front gasket and the back gasket have inverted symmetrical shapes relative to each other. Therefore, when the front dipole plate and the back dipole plate are stacked inverted in the front-to-back direction, the shape of the front gasket of the front dipole plate and the shape of the front gasket of the back dipole plate coincide (they are geometrically congruent) when viewed from the front-to-back direction. Similarly, the shape of the back gasket of the front dipole plate and the shape of the back gasket of the back dipole plate coincide when viewed from the front-to-back direction. Thus, with this configuration, a stacked body can be easily assembled by stacking the front dipole plate and the back dipole plate inverted in the front-to-back direction.

[0014] (2) In any of the above configurations, the front gasket has a front base layer laminated on the front placement portion and having a front through hole that penetrates itself in the front-to-back direction, and a front connecting portion formed on the front base layer that connects the first manifold and the front flow path area, and the back gasket has a back base layer laminated on the back placement portion and having a back through hole that penetrates itself in the front-to-back direction, and a back connecting portion formed on the back base layer that connects the second manifold and the back flow path area, and the water electrolytic device The apparatus comprises a laminate in which the double-sided gasketed bipolar plates and water electrolytic members are alternately stacked in the front-back direction, wherein any of the water electrolytic members is designated as a reference water electrolytic member, the double-sided gasketed bipolar plate stacked adjacent to the front side of the reference water electrolytic member is designated as a front-side bipolar plate, and the double-sided gasketed bipolar plate stacked adjacent to the back side of the reference water electrolytic member is designated as a back-side bipolar plate, and the back-side connecting portion of the front-side bipolar plate and the front-side connecting portion of the back-side bipolar plate are configured to elastically contact the reference water electrolytic member.

[0015] In this configuration, the front-side connecting portion ensures a flow path for the first fluid between the first manifold and the front-side flow path area. Furthermore, the front-side connecting portion of the rear-side bipolar plate can be sealed by elastically contacting the reference water electrolytic member.

[0016] Similarly, with this configuration, the rear-side connecting portion ensures a flow path for the second fluid between the second manifold and the rear-side flow path area. Furthermore, the rear-side connecting portion of the front-side bipolar plate can be sealed by elastically contacting the reference water electrolysis member.

[0017] Furthermore, in this configuration, the front gasket has a front connecting portion, and the back gasket has a back connecting portion. This allows for greater flexibility in the shape of the bipolar plate body.

[0018] (2-1) In any of the above configurations, the water electrolysis apparatus comprises a laminate in which the double-sided gasketed bipolar plates and water electrolysis members are alternately stacked in the front-back direction, wherein any of the water electrolysis members is designated as a reference water electrolysis member, the double-sided gasketed bipolar plate stacked adjacent to the front side of the reference water electrolysis member is designated as a front-side bipolar plate, and the double-sided gasketed bipolar plate stacked adjacent to the back side of the reference water electrolysis member is designated as a back-side bipolar plate, and the back-side gasket of the front-side bipolar plate and the front-side gasket of the back-side bipolar plate may comprise at least one of the following configurations (Configuration A) and (Configuration B).

[0019] (Configuration A) When viewed from the stacking direction, at least a portion of the back-side connecting portion of the front-side bipolar plate and at least a portion of the front-side gasket of the back-side bipolar plate overlap each other.

[0020] (Configuration B) When viewed from the stacking direction, at least a portion of the front-side connecting portion of the back-side bipolar plate and at least a portion of the back-side gasket of the front-side bipolar plate overlap each other.

[0021] According to (Configuration A), when viewed from the lamination direction, at least a portion of the back-side connecting portion of the front-side bipolar plate and at least a portion of the front-side gasket of the back-side bipolar plate overlap each other. This allows for high shape stability of the laminate. Furthermore, the fastening force applied to the laminate from both sides in the lamination direction is less likely to escape from the contact area between the back-side connecting portion of the front-side bipolar plate and the reference water electrolysis member. This improves the sealing performance of the back-side connecting portion.

[0022] According to (Configuration B), when viewed from the lamination direction, at least a portion of the front-side connecting portion of the back-side bipolar plate and at least a portion of the back-side gasket of the front-side bipolar plate overlap each other. This allows for high shape stability of the laminate. Furthermore, the fastening force applied to the laminate from both sides in the lamination direction is less likely to escape from the contact area between the front-side connecting portion of the back-side bipolar plate and the reference water electrolysis member. This improves the sealing performance of the front-side connecting portion.

[0023] (2-2) In the configuration of (2) or (2-1) above, the front connecting portion may have a plurality of front protrusions projecting outward from the front base layer and a front groove portion partitioned between a pair of adjacent front protrusions through which the first fluid flows, and the back connecting portion may have a plurality of back protrusions projecting outward from the back base layer and a back groove portion partitioned between a pair of adjacent back protrusions through which the second fluid flows.

[0024] In this configuration, the front groove is partitioned using the front base layer and front protrusions of the front gasket. Similarly, the back groove is partitioned using the back base layer and back protrusions of the back gasket. This allows for greater flexibility in the shape of the bipolar plate body.

[0025] (3) In any of the above configurations, the front-side configuration portion may have a front-side gasket uneven portion having undulations in the front-back direction, and the back-side configuration portion may have a back-side gasket uneven portion having undulations in the front-back direction, and the front-side gasket uneven portion and the back-side gasket uneven portion may be arranged opposite each other in the front-back direction and exhibit a shape that is symmetrical with respect to each other.

[0026] According to this configuration, the front-side mounting portion has a front-side gasket uneven surface with undulations in the front-back direction. The front-side gasket uneven surface suppresses misalignment of the front-side gasket relative to the front-side mounting portion. Therefore, adhesive (specifically, adhesive for bonding the front-side gasket to the front-side mounting portion) becomes unnecessary. Consequently, during the manufacturing of a bipolar plate with double-sided gaskets, bonding-related processes (for example, a cleaning process to clean the front-side mounting portion, a coating process to apply adhesive to the front-side mounting portion after cleaning, and an inspection process to check the condition of the adhesive after application) can be omitted. Furthermore, the front-side gasket uneven surface has an uneven shape. Therefore, the bending rigidity of the bipolar plate body can be improved.

[0027] Similarly, the rear-side mounting portion has a rear-side gasket uneven surface with undulations in the front-back direction. The rear-side gasket uneven surface suppresses misalignment of the rear-side gasket relative to the rear-side mounting portion. Therefore, adhesive is not required. Consequently, the bonding process can be omitted during the manufacturing of a bipolar plate with double-sided gaskets. In addition, the rear-side gasket uneven surface has an uneven shape. Therefore, the bending rigidity of the bipolar plate body can be improved.

[0028] Furthermore, in this configuration, the gasket protrusions on the front side and the gasket protrusions on the back side are arranged opposite each other in the front-back direction (they overlap when viewed from the front-back direction). Also, the gasket protrusions on the front side and the gasket protrusions on the back side have a shape that is symmetrical to each other. Therefore, the gasket protrusions on the front side and the gasket protrusions on the back side can be formed and arranged on the bipolar plate body simultaneously by press molding. This improves the productivity of bipolar plates with gaskets on both sides.

[0029] This configuration is particularly suitable when the adhesive is weak against at least one of the properties of the first fluid (alkaline, acidic, etc.) and the second fluid. By adopting this configuration, displacement of the front gasket relative to the front mounting portion can be suppressed without using an adhesive. Similarly, displacement of the back gasket relative to the back mounting portion can be suppressed without using an adhesive.

[0030] (3-1) In the configuration of (3) above, when viewed from the front and back directions, the front gasket uneven portion and the back gasket uneven portion may overlap with the front first seal portion, the front second seal portion, the back first seal portion, and the back second seal portion.

[0031] In this configuration, the gasket irregularities on the front side and the gasket irregularities on the back side are arranged along all sealing sections (first sealing section on the front side, second sealing section on the front side, first sealing section on the back side, and second sealing section on the back side). Therefore, misalignment of all sealing sections can be suppressed intensively. Consequently, the sealing performance of all sealing sections can be improved.

[0032] (4) In any of the above configurations, the bipolar plate body has a through hole that penetrates it in the front-to-back direction, and when viewed from the front-to-back direction, the front-side first seal portion, the front-side second seal portion, the back-side first seal portion, and the back-side second seal portion each have an annular shape, and when viewed from the front-to-back direction, the through hole is located on the outer side of the annular shape of the front-side first seal portion, the front-side second seal portion, the back-side first seal portion, and the back-side second seal portion, and the gasket has an elastomer connecting portion that connects the front-side gasket and the back-side gasket in the front-to-back direction and is located inside the through hole, and the front-side gasket, the back-side gasket and the connecting portion may be configured to be integrally connected.

[0033] In this configuration, the gasket has a connecting portion. The connecting portion allows the front gasket, the bipolar plate body, and the back gasket to be integrated. Therefore, adhesive is not required. Consequently, the bonding process can be omitted during the manufacturing of bipolar plates with double-sided gaskets. This configuration is particularly suitable when the adhesive is weak against at least one of the liquid properties of the first fluid and the second fluid. By adopting this configuration, separation of the front gasket, bipolar plate body, and back gasket can be suppressed even without using adhesive.

[0034] Furthermore, with this configuration, when viewed from the front and back directions, the through holes are located on the outer ring side (unsealed side, atmospheric side) of the entire sealing portion (front side first sealing portion, front side second sealing portion, back side first sealing portion, back side second sealing portion). Therefore, compared to the case where the through holes are located on the inner ring side (first fluid side, second fluid side) of the entire sealing portion, leakage of the first and second fluids through the through holes can be suppressed.

[0035] (5) In the configuration of (4) above, the gasket may be configured such that the front gasket and the back gasket are connected in the front-back direction, and the covering portion covers the inner circumferential surface of the first manifold and the inner circumferential surface of the second manifold, and the front gasket, the back gasket and the covering portion are integrally connected.

[0036] The bipolar plate body is made of metal. Therefore, the inner surfaces of the first manifold and the second manifold are also made of metal. In this configuration, the inner surfaces of the first manifold and the second manifold are covered by an elastomer coating. This protects the metal inner surface of the first manifold from the first fluid and other contaminants. Similarly, it protects the metal inner surface of the second manifold from the second fluid and other contaminants.

[0037] Furthermore, according to this configuration, the gasket has a covering portion in addition to the connecting portion described in (4) above. The covering portion allows the front gasket, the bipolar plate body, and the back gasket to be integrated. Therefore, adhesive is not required. Consequently, the bonding process can be omitted during the manufacturing of a bipolar plate with gaskets on both sides. This configuration is particularly suitable when the adhesive is weak against at least one of the liquid properties of the first fluid and the second fluid. By adopting this configuration, separation of the front gasket, the bipolar plate body, and the back gasket can be suppressed without using adhesive.

[0038] (6) In any of the above configurations, the front channel area may have a front channel uneven portion having undulations in the front-back direction, and the back channel area may have a back channel uneven portion having undulations in the front-back direction, and the front channel uneven portion and the back channel uneven portion may be arranged opposite each other in the front-back direction and exhibit a shape that is symmetrical to each other.

[0039] In this configuration, the front channel area has a surface with irregularities in the front-to-back direction. These surface irregularities suppress variations in the flow of the first fluid (such as turbulence). Therefore, the reaction efficiency of water electrolysis (electrolysis) can be improved. Furthermore, the surface channel irregularities have an uneven shape. Therefore, the bending rigidity of the bipolar plate body can be improved.

[0040] Similarly, the back-side flow path area has back-side flow path concavo-convex portions having undulations in the front-back direction. The back-side flow path concavo-convex portions can suppress variations in the flow of the second fluid. Therefore, the reaction efficiency of water electrolysis can be improved. Further, the back-side flow path concavo-convex portions have a concavo-convex shape. Therefore, the bending rigidity of the bipolar plate body can be improved.

[0041] (7) In the configuration of (6) above, the water electrolysis device includes a laminate in which the bipolar plate with double-sided gaskets and the water electrolysis member are alternately laminated in the front-back direction. In the laminate, any one of the water electrolysis members is defined as a reference water electrolysis member, the bipolar plate with double-sided gaskets laminated adjacent to the front side of the reference water electrolysis member is defined as a front-side bipolar plate, and the bipolar plate with double-sided gaskets laminated adjacent to the back side of the reference water electrolysis member is defined as a back-side bipolar plate. Taking any pair of intersecting directions as the X direction and the Y direction, the plane including the X direction and the Y direction as the XY plane, and the direction intersecting the X direction and the Y direction in the XY plane as the inclined direction, the bipolar plate body has a rectangular shape having a pair of X sides extending in the X direction and a pair of Y sides extending in the Y direction. The front-side flow path concavo-convex portions have front-side inclined portions extending in the inclined direction, the back-side flow path concavo-convex portions have back-side inclined portions extending in the same direction as the front-side inclined portions, the front-side inclined portions and the back-side inclined portions are arranged to face each other in the front-back direction and have a shape that is mirror-symmetrical to each other. In the laminate, the front-side bipolar plate and the back-side bipolar plate may be laminated in a configuration that is inverted in the front-back direction with respect to the X side or the Y side as a reference.

[0042] Let's assume that the front and back bipolar plates are stacked as they are (in an unreversed state). The channel irregularities on the front and back sides are symmetrical to each other. Therefore, in the stacked structure, there is a risk that the channel irregularities on the back side of the front bipolar plate and the channel irregularities on the front side of the back bipolar plate may become interlocked with each other, with the reference water electrolysis member in between (hereinafter, this phenomenon will be referred to as "interlocking" as appropriate). An example of interlocking is when, for example, the protrusions of the channel irregularities on the front side of the back bipolar plate become interlocked with the recesses of the channel irregularities on the back bipolar plate via the reference water electrolysis member. Another example is when, for example, the protrusions of the channel irregularities on the back bipolar plate become interlocked with the recesses of the channel irregularities on the front bipolar plate via the reference water electrolysis member. It should be noted that these two cases are likely to occur simultaneously. When jamming occurs, the reference water electrolysis component becomes more susceptible to deformation into an uneven shape that conforms to the shape of the uneven surfaces of the front and back channel.

[0043] In this configuration, the front channel irregularities have a front inclined portion, and the back channel irregularities have a back inclined portion. The front inclined portion and the back inclined portion extend in the same direction (the inclination direction (a direction intersecting the X and Y directions)). Furthermore, the front bipolar plate and the back bipolar plate are stacked inverted in the front-back direction with respect to the X or Y side. Therefore, when viewed from the front-back direction, the back inclined portion of the front bipolar plate and the front inclined portion of the back bipolar plate can extend in different directions from each other (for example, in directions that intersect in an X shape when viewed from the front-back direction). Consequently, interlocking can be suppressed. Thus, deformation of the reference water electrolytic member caused by interlocking can be suppressed.

[0044] Further, focusing on an arbitrary and single bipolar plate with a double-sided gasket, when viewed from the front and back directions, the front-side inclined portion and the back-side inclined portion extend in the same direction. By simply stacking a plurality of such bipolar plates with double-sided gaskets in an alternating manner, reversing them in the front and back directions every other one, when viewed from the front and back directions, the back-side inclined portion of the front-side bipolar plate and the front-side inclined portion of the back-side bipolar plate can be made to extend in different directions from each other. For example, only the bipolar plates with double-sided gaskets corresponding to odd numbers when counted from one end in the stacking direction may be reversed in the front and back directions and stacked. Alternatively, only the bipolar plates with double-sided gaskets corresponding to even numbers when counted from one end in the stacking direction may be reversed in the front and back directions and stacked. Thus, according to this configuration, by simply devising the method of stacking the bipolar plates with double-sided gaskets, fitting can be easily suppressed.

[0045] (7-1) In any of the above configurations, the water electrolysis device includes a laminate in which the bipolar plates with double-sided gaskets and the water electrolysis members are alternately stacked in the front and back directions. In the laminate, any of the water electrolysis members is used as a reference water electrolysis member, the bipolar plate with a double-sided gasket stacked adjacent to the front side of the reference water electrolysis member is used as the front-side bipolar plate, and the bipolar plate with a double-sided gasket stacked adjacent to the back side of the reference water electrolysis member is used as the back-side bipolar plate. A configuration may be adopted in which the back surface shape of the bipolar plate body of the front-side bipolar plate and the front surface shape of the bipolar plate body of the back-side bipolar plate exhibit non-mirror-symmetric shapes with respect to each other.

[0046] Here, "the back surface shape of the bipolar plate body of the front-side bipolar plate and the front surface shape of the bipolar plate body of the back-side bipolar plate exhibit non-mirror-symmetric shapes with respect to each other" means that there is a portion that does not exhibit a mirror-symmetric shape between the back surface shape of the bipolar plate body of the front-side bipolar plate and the front surface shape of the bipolar plate body of the back-side bipolar plate.

[0047] According to this configuration, it is possible to suppress the back surface shape of an arbitrary front-side bipolar plate and the front surface shape of the back-side bipolar plate (facing each other across the reference water electrolysis member) stacked adjacent to the back side of the front-side bipolar plate across the reference water electrolysis member from becoming completely mirror-symmetric. Therefore, fitting can be suppressed. Thus, deformation of the reference water electrolysis member caused by fitting can be suppressed.

[0048] (8) In order to solve the above problems, the water electrolysis apparatus of the present disclosure is characterized by comprising a laminate in which a bipolar plate with double-sided gaskets having any of the above configurations and a water electrolysis member having an electrolyte membrane are alternately stacked in the front-back direction. This configuration has the same effects as the configuration of (1) above.

[0049] (8-1) In the configuration of (8) above, the electrolyte membrane may be an anion exchange membrane or a proton exchange membrane. In the laminate, any water electrolytic member is defined as the reference water electrolytic member, a double-sided gasketed bipolar plate laminated adjacent to the front side of the reference water electrolytic member is defined as the front side bipolar plate, and a double-sided gasketed bipolar plate laminated adjacent to the back side of the reference water electrolytic member is defined as the back side bipolar plate.

[0050] If the electrolyte membrane of the reference water electrolytic component is an anion exchange membrane, hydroxide ions can be conducted via the electrolyte membrane from the back channel area of ​​the front bipolar plate (the channel area for the second fluid on the cathode side) to the front channel area of ​​the back bipolar plate (the channel area for the first fluid on the anode side). Also, if the electrolyte membrane of the reference water electrolytic component is a proton exchange membrane, hydrogen ions can be conducted via the electrolyte membrane from the front channel area of ​​the back bipolar plate to the back channel area of ​​the front bipolar plate.

[0051] (9) In the configuration of (8) or (8-1) above, the bipolar plate body, the front channel area has a front channel uneven portion having undulations in the front-back direction, the back channel area has a back channel uneven portion having undulations in the front-back direction, the front channel uneven portion and the back channel uneven portion are arranged opposite each other in the front-back direction and exhibit a symmetrical shape, and in the laminate, any water electrolytic member is a reference water electrolytic member, the bipolar plate with double gaskets laminated adjacent to the front side of the reference water electrolytic member is a front bipolar plate, and the bipolar plate with double gaskets laminated adjacent to the back side of the reference water electrolytic member is a back bipolar plate, and any pair of intersecting directions are the X direction and the Y direction With respect to the XY plane, which includes the X, Y directions, and the X-direction, and the inclination direction, the bipolar plate body has a quadrilateral shape with a pair of X sides extending in the X direction and a pair of Y sides extending in the Y direction. The front channel undulation portion has a front inclined portion extending in the inclination direction, and the back channel undulation portion has a back inclined portion extending in the same direction as the front inclined portion. The front inclined portion and the back inclined portion are arranged opposite each other in the front-back direction and have a shape that is symmetrical to each other. In the laminate, the front bipolar plate and the back bipolar plate may be laminated inverted in the front-back direction with respect to the X side or the Y side. This configuration has the same effects as the configuration of (7) above.

[0052] (10) In any of the configurations described in (8) to (9) above, the water electrolysis member may have a configuration comprising an electrolytic section having the electrolyte membrane and a frame section surrounding the electrolytic section and having higher rigidity than the electrolyte membrane. This configuration makes it possible to improve the shape stability of the electrolyte membrane in the electrolytic section.

[0053] (11) In order to solve the above problems, the present disclosure is a method for manufacturing a bipolar plate with a double gasket, comprising any of the configurations (1) to (7-1) above, the method comprising: a press molding step of manufacturing the bipolar plate body by press molding; and an insert molding step of molding the gasket in a cavity in which the bipolar plate body is arranged and joining the gasket to the bipolar plate body, wherein the insert molding step comprises: an arrangement step of arranging the bipolar plate body in a mold of an insert molding die that partitions the cavity; a raw material injection step of injecting raw material into the cavity of the insert molding die; and a curing step of curing the raw material injected into the cavity to integrally form the gasket and joining the gasket to the bipolar plate body.

[0054] The manufacturing method for the double-sided gasketed bipolar plate of this configuration comprises a press molding step and an insert molding step. The insert molding step comprises a placement step, a raw material injection step and a curing step.

[0055] The press molding process allows the first manifold, second manifold, front flow path area, front mounting section, back flow path area, and back mounting section to be simultaneously molded and positioned on the bipolar plate body. Furthermore, the insert molding process allows the gasket to be integrally molded and bonded to the bipolar plate body. Thus, this configuration allows for the efficient manufacture of a bipolar plate with gaskets on both sides, with any of the above configurations (1) to (7-1), with fewer manufacturing steps.

[0056] (12) In the configuration of (11) above, the raw material injection step may be configured to inject the raw material into the cavity of the insert molding die from at least one of the first manifold and the second manifold. With this configuration, at least one of the first manifold and the second manifold can be used as a raw material injection section into the cavity in the raw material injection step.

[0057] (13) In the configuration of (11) or (12) above, the front side arrangement portion has a front side gasket uneven portion having undulations in the front-back direction, the back side arrangement portion has a back side gasket uneven portion having undulations in the front-back direction, the front side gasket uneven portion and the back side gasket uneven portion are arranged opposite each other in the front-back direction and have a symmetrical shape, the press molding die used in the press molding process has a front side molding portion that forms the front side gasket uneven portion and the back side gasket The press molding die has a front molding section and a back molding section for forming the gasket's uneven portion, and the front molding section and the back molding section are arranged opposite each other in the opening and closing direction of the press molding die and have a symmetrical shape to each other. In the press molding process, the front molding section and the back molding section sandwich the bipolar plate body or an intermediate product of the bipolar plate body, thereby forming the front gasket uneven portion on the front mounting section and the back gasket uneven portion on the back mounting section. With this configuration, the front gasket uneven portion and the back gasket uneven portion can be formed and positioned simultaneously in the press molding process.

[0058] (14) In any of the configurations (11) to (13) above, the bipolar plate body has a through hole that penetrates itself in the front-to-back direction, and when viewed from the front-to-back direction, the front-side first seal portion, the front-side second seal portion, the back-side first seal portion, and the back-side second seal portion each have an annular shape, and when viewed from the front-to-back direction, the through hole is located on the outer side of the annular shape of the front-side first seal portion, the front-side second seal portion, the back-side first seal portion, and the back-side second seal portion, and the gasket is located inside the through hole The device may have an elastomer connecting portion positioned to connect the front gasket and the back gasket in the front-back direction, wherein the front gasket, the back gasket, and the connecting portion are integrally connected, and in the raw material injection process, the raw material is allowed to flow through the through hole in the front-back direction of the bipolar plate body, and in the curing process, the raw material in the through hole is cured, forming the connecting portion together with the front gasket and the back gasket.

[0059] With this configuration, during the raw material injection process, the raw material can be distributed to both the front and back sides of the bipolar plate body through the through-holes. Furthermore, during the curing process, the raw material in the through-holes is cured, and the connecting portion can be formed together with the front gasket and the back gasket. The connecting portion integrates the front gasket, the bipolar plate body, and the back gasket. Therefore, adhesive is not required. Accordingly, in the manufacturing method of a bipolar plate with double-sided gaskets, the adhesive-related process can be omitted. This configuration is particularly suitable when the adhesive is weak against at least one of the liquid properties of the first fluid and the second fluid. By adopting this configuration, separation of the front gasket, the bipolar plate body, and the back gasket can be suppressed without using adhesive.

[0060] Furthermore, with this configuration, when viewing the bipolar plate body from the front and back directions, the through holes are located on the outer side (atmospheric side) of the entire sealing section (first sealing section on the front side, second sealing section on the front side, first sealing section on the back side, and second sealing section on the back side). Therefore, compared to the case where the through holes are located on the inner side (first fluid side, second fluid side), leakage of the first and second fluids through the through holes can be suppressed.

[0061] (15) In any of the configurations (11) to (14) above, the front gasket has an elastomer front base layer laminated on the front placement portion, the first front seal portion and the second front seal portion are laminated on the surface of the front base layer, the back gasket has an elastomer back base layer laminated on the back placement portion, the first back seal portion and the second back seal portion are laminated on the back surface of the back base layer, and the cavity of the insert molding die may have a front base layer molding portion for molding the front base layer and a back base layer molding portion for molding the back base layer.

[0062] According to this configuration, in the raw material injection process, the raw material can be distributed to the front first seal portion and the front second seal portion via the front base layer molding portion. In addition, the raw material can be distributed to the back first seal portion and the back second seal portion via the back base layer molding portion.

[0063] (16) In order to solve the above problems, a method for manufacturing a water electrolysis apparatus according to the present disclosure is a method for manufacturing a water electrolysis apparatus comprising a laminate in which a double-sided gasketed bipolar plate having any of the configurations (1) to (7-1) above and a water electrolysis member having an electrolyte membrane are alternately stacked in the front-back direction, characterized in that the method comprises a stacking step of alternately stacking the double-sided gasketed bipolar plate and the water electrolysis member in the front-back direction to produce the laminate, and a fastening step of placing end plates on both ends of the laminate in the stacking direction and applying a fastening force to the laminate from the stacking direction to press-fit adjacent double-sided gasketed bipolar plates and the water electrolysis member in the stacking direction.

[0064] According to the manufacturing method of this water electrolysis device, a laminate is produced in the lamination process, and in the fastening process, the laminate is sandwiched between end plates from both sides in the lamination direction, allowing the bipolar plate with double-sided gaskets and the water electrolysis component to be pressed together. Therefore, a water electrolysis device can be easily manufactured. In addition, the fastening process can improve the sealing performance of the first seal portion on the front side, the second seal portion on the front side, the first seal portion on the back side, and the second seal portion on the back side.

[0065] (17) In the configuration of (16) above, in the laminate, any water electrolytic member is designated as a reference water electrolytic member, the double-sided gasketed bipolar plate laminated adjacent to the front side of the reference water electrolytic member is designated as a front bipolar plate, and the double-sided gasketed bipolar plate laminated adjacent to the back side of the reference water electrolytic member is designated as a back bipolar plate, and any pair of intersecting directions is designated as the X direction and the Y direction, the plane containing the X direction and the Y direction is designated as the XY plane, and the directions intersecting the X direction and the Y direction within the XY plane are designated as the inclination direction, the bipolar plate body has a pair of X sides extending in the X direction and a pair of Y sides extending in the Y direction. The surface has a rectangular shape, the front channel surface has a front inclined portion extending in the direction of inclination, the back channel surface has a back inclined portion extending in the same direction as the front inclined portion, the front inclined portion and the back inclined portion are arranged opposite each other in the front-back direction and have a shape that is symmetrical to each other, and the lamination process may be configured as an inversion lamination process in which the front bipolar plate and the back bipolar plate are laminated in the front-back direction with respect to the X side or the Y side, so that when viewed from the front-back direction, the back inclined portion of the front bipolar plate and the front inclined portion of the back bipolar plate extend in different directions from each other.

[0066] This configuration includes a reverse lamination process. In the reverse lamination process, the front-side bipolar plate and the back-side bipolar plate are reversed in the front-to-back direction based on the X or Y side and then laminated. For example, the back-side bipolar plate is reversed in the front-to-back direction based on the X or Y side and then laminated relative to the front-side bipolar plate. Similarly, the front-side bipolar plate is reversed in the front-to-back direction based on the X or Y side and then laminated relative to the back-side bipolar plate. By reverse laminating the front-side bipolar plate and the back-side bipolar plate in this way, the inclined portion on the back side of the front-side bipolar plate and the inclined portion on the front side of the back-side bipolar plate can be made to extend in different directions when viewed from the front-to-back direction. This configuration has the same effects as the configuration described in (7) above.

[0067] (17-1) In the configuration of (16) above, in the laminate, any water electrolytic member is designated as a reference water electrolytic member, the double-sided gasketed bipolar plate laminated adjacent to the front side of the reference water electrolytic member is designated as a front-side bipolar plate, and the double-sided gasketed bipolar plate laminated adjacent to the back side of the reference water electrolytic member is designated as a back-side bipolar plate. The lamination process may be configured as an inverted lamination process in which a plurality of double-sided gasketed bipolar plates are laminated alternately in the front-to-back direction, such that the back surface shape of the bipolar plate body of the front-side bipolar plate and the surface shape of the bipolar plate body of the back-side bipolar plate exhibit asymmetric shapes with respect to each other. This configuration has the same effects as the configuration of (7-1) above.

[0068] Here, "the back surface shape of the bipolar plate body of the front bipolar plate and the front surface shape of the bipolar plate body of the back bipolar plate exhibit asymmetric shapes" means that there is a portion between the back surface shape of the bipolar plate body of the front bipolar plate and the front surface shape of the bipolar plate body of the back bipolar plate that does not exhibit a symmetric shape.

[0069] This configuration makes it possible to suppress the complete symmetry between the back surface shape of any front-side bipolar plate and the back surface shape of a front-side bipolar plate stacked adjacent to the back surface of the front-side bipolar plate (facing each other across the reference water electrolytic member). Therefore, it is possible to suppress interlocking. Consequently, it is possible to suppress deformation of the reference water electrolytic member caused by interlocking.

[0070] According to this disclosure, it is possible to provide a highly productive bipolar plate with double-sided gaskets, a water electrolysis apparatus equipped with the bipolar plate with double-sided gaskets, a method for manufacturing the bipolar plate with double-sided gaskets, and a method for manufacturing a water electrolysis apparatus equipped with the bipolar plate with double-sided gaskets.

[0071] Figure 1 is a front view of a water electrolysis apparatus equipped with a double-sided gasketed bipolar plate according to one embodiment of the double-sided gasketed bipolar plate of the present disclosure. Figure 2 is an exploded perspective view of section II of Figure 1. Figure 3 is a perspective view showing the method of laminating the front and back bipolar plates of Figure 2. Figure 4 is a top view of the double-sided gasketed bipolar plate. Figure 5 is a top view of the bipolar plate body of the double-sided gasketed bipolar plate. Figure 6 is a top view of the front gasket of the double-sided gasketed bipolar plate. Figure 7 is a bottom view of the double-sided gasketed bipolar plate. Figure 8 is a bottom view of the bipolar plate body of the double-sided gasketed bipolar plate. Figure 9 is a bottom view of the back gasket of the double-sided gasketed bipolar plate. Figure 10 is a top view of the water electrolysis member of the double-sided gasketed bipolar plate. Figure 11 is an enlarged view of the area within frame XI of Figure 4. Figure 12 is a cross-sectional view taken in the direction of XII-XII of Figure 11. Figure 13 is an enlarged view of the area within frame XIII in Figure 4. Figure 14 is an enlarged view of the area within frame XIII in Figure 7. Figure 15 is a cross-sectional view of Figure 13 in the direction XV-XV. Figure 16(A) is an enlarged view of the area within frame XVIA in Figure 15. Figure 16(B) is an enlarged view of the area within frame XVIB in Figure 15. Figure 17 is a top view of the front gasket and back gasket of the double-sided gasketed bipolar plate superimposed. Figure 18 is an enlarged view of the area within frame XIII in Figure 17. Figure 19(A) is a partial vertical cross-sectional view of the press forming die in the early stage of the plate deformation process in the press forming process of the manufacturing method of the double-sided gasketed bipolar plate. Figure 19(B) is a partial vertical cross-sectional view of the press forming die in the later stage of the plate deformation process. Figure 19(C) is a partial vertical cross-sectional view of the bipolar plate body in the first punching process of the press forming process. Figure 19(D) is a partial vertical cross-sectional view of the bipolar plate body during the second punching step of the press forming process. Figure 20(A) is a partial vertical cross-sectional view of the insert molding die during the arrangement step of the insert molding process for manufacturing the bipolar plate with double gaskets. Figure 20(B) is a partial vertical cross-sectional view of the insert molding die during the raw material injection step of the insert molding process. Figure 21(A) is a partial vertical cross-sectional view of the insert molding die during the initial stage of the curing step of the insert molding process for manufacturing the bipolar plate with double gaskets.Figure 21(B) is a partial vertical cross-sectional view of the insert molding die during the later stages of the curing process. Figures 22(A) to 22(D) are schematic top views of bipolar plates with double-sided gaskets in other embodiments (1 to 4).

[0072] The following describes embodiments of the double-sided gasketed bipolar plate, a water electrolysis apparatus equipped with the double-sided gasketed bipolar plate, a method for manufacturing the double-sided gasketed bipolar plate, and a method for manufacturing the water electrolysis apparatus equipped with the double-sided gasketed bipolar plate.

[0073] <Regarding the correspondence between the constituent elements of this disclosure and the drawings> First, we will explain the correspondence between the directions in the following drawings and the directions of this disclosure. In the following drawings, the left-right direction corresponds to the "X direction" of this disclosure, the front-back direction corresponds to the "Y direction" of this disclosure, and the horizontal plane (layer surface) corresponds to the "XY plane" of this disclosure. The left-right direction and the front-back direction are orthogonal (intersecting) with each other. The upper side corresponds to the "front side" of this disclosure, the lower side corresponds to the "back side" of this disclosure, and the up-down direction corresponds to the "front-back direction" and "lamination direction" of this disclosure. The horizontal plane is a plane that includes the left-right direction and the front-back direction. The horizontal plane extends in a direction that is orthogonal (intersecting) with respect to the up-down direction. The inclination direction is a direction that intersects with respect to the left-right direction and the front-back direction within the horizontal plane.

[0074] Figure 1 shows a front view of a water electrolysis apparatus equipped with a double-sided gasketed bipolar plate according to this embodiment. Figure 2 shows an exploded perspective view of section II in Figure 1. Figure 3 shows a perspective view showing the lamination method of the front and back bipolar plates in Figure 2. In Figure 1, the double-sided gasketed bipolar plate 2 (hereinafter abbreviated as "bipolar plate 2" as appropriate) and the water electrolysis member 6 are shown in a simplified manner. In Figures 2 and 3, the configuration of the upper surface (front surface) 20U of the bipolar plate body 20 is shown in a simplified manner.

[0075] <Water Electrolyzer 9> Next, the configuration of the water electrolyzer 9 of this embodiment will be described. As shown in Figure 1, the water electrolyzer 9 comprises a pair of upper and lower end plates 90 and a laminate 91. The laminate 91 comprises a plurality of bipolar plates 2 and a plurality of water electrolyzer members 6. The plurality of bipolar plates 2 and the plurality of water electrolyzer members 6 are stacked alternately in the vertical direction. A potential difference for electrolysis is applied to both ends of the laminate 91 in the vertical direction.

[0076] The pair of upper and lower end plates 90 sandwich the laminate 91 from above and below. The pair of upper and lower end plates 90 are connected by a pair of left and right tie rods 92 that penetrate the laminate 91. The tie rods 92 are included in the concept of "fastening members" in this disclosure. A fastening force F is applied to the laminate 91 from above and below (from the outside in the lamination direction) by the tie rods 92.

[0077] The bipolar plates 2 and the water electrolysis member 6 that constitute the laminate 91 are not bonded to each other. These members are positioned vertically and horizontally (front, back, left, and right) by the fastening force F described above.

[0078] <Regarding the reference numerals of the bipolar plate 2 and water electrolysis member 6> Next, the reference numerals of the bipolar plate 2 and water electrolysis member 6 will be explained. As shown in Figures 1 and 2, when any water electrolysis member 6 is designated as the "reference water electrolysis member 6M", the bipolar plate 2 laminated adjacent to the upper side of the reference water electrolysis member 6M is designated as the "front bipolar plate 2U". Similarly, the bipolar plate 2 laminated adjacent to the lower side of the reference water electrolysis member 6M is designated as the "back bipolar plate 2D".

[0079] The configurations of the multiple bipolar plates 2 are identical to each other. However, the multiple bipolar plates 2 are stacked with alternating vertical inversions. Therefore, as shown in Figure 3, the upper surface of the front bipolar plate 2U corresponds to the lower surface of the back bipolar plate 2D. Similarly, the lower surface of the front bipolar plate 2U corresponds to the upper surface of the back bipolar plate 2D. Also, as shown in Figure 2, when viewed from above, the inclined portions of the front bipolar plate 2U (front inclined portion 23U, back inclined portion) and the inclined portions of the back bipolar plate 2D (front inclined portion 23U, back inclined portion) intersect each other in an X-shape. That is, the extending direction of the inclined portion of the front bipolar plate 2U (front left - rear right direction) and the extending direction of the inclined portion of the back bipolar plate 2D (front right - rear left direction) are different from each other.

[0080] <Double-sided gasketed bipolar plate 2> Next, the configuration of the bipolar plate 2 will be described. Figure 4 shows a top view of the double-sided gasketed bipolar plate of this embodiment (specifically, the back side bipolar plate 2D in Figure 2). Figure 5 shows a top view of the bipolar plate body of the double-sided gasketed bipolar plate. Figure 6 shows a top view of the front side gasket of the double-sided gasketed bipolar plate. Figure 7 shows a bottom view of the double-sided gasketed bipolar plate. Figure 8 shows a bottom view of the bipolar plate body of the double-sided gasketed bipolar plate. Figure 9 shows a bottom view of the back side gasket of the double-sided gasketed bipolar plate. Figure 10 shows a top view of the water electrolysis member of the double-sided gasketed bipolar plate. Figure 11 shows an enlarged view of the area within frame XI in Figure 4. Figure 12 shows a cross-sectional view in the direction of XII-XII in Figure 11. Figure 13 shows an enlarged view of the area within frame XIII in Figure 4. Figure 14 shows an enlarged view of the area within frame XIII in Figure 7. Figure 15 shows a cross-sectional view in the XV-XV direction of Figure 13. Figure 16(A) shows an enlarged view of the area within frame XVIA in Figure 15. Figure 16(B) shows an enlarged view of the area within frame XVIB in Figure 15. Figure 17 shows a top view of the double-sided gasketed bipolar plate with the front and back gaskets superimposed. Figure 18 shows an enlarged view of the area within frame XIII in Figure 17.

[0081] In each figure, frame XIII indicates a common portion (the left front portion of the double-sided gasketed bipolar plate 2). Similarly, frame XI in each figure indicates a common portion (the horizontal central portion of the double-sided gasketed bipolar plate 2). In Figure 5, the section of the front gasket protrusions 26U that overlaps with the front first seal portion 52U and the front second seal portion 53U (see Figure 6) is shown with a solid line. The section that overlaps only with the back first seal portion 52D and the back second seal portion 53D (see Figure 9) is shown with a dotted line. In contrast, in Figure 8, the section of the back gasket protrusions 26D that overlaps with the back first seal portion 52D and the back second seal portion 53D is shown with a solid line. The section that overlaps only with the front first seal portion 52U and the front second seal portion 53U is shown with a dotted line. In Figure 11, hatching is applied to the front protrusion 220U. Furthermore, in Figure 11, the inclined portions of the front bipolar plate 2U (front inclined portion 23U, back inclined portion 23D) are shown by dotted lines. Also, in Figure 15, a cross-sectional view in the vertical direction of a part of the laminate 91 (section II in Figure 1) is shown.

[0082] As shown in Figures 4 to 10, when viewed from above, the linear axis extending horizontally through the centroid C of each member is defined as "axis CX". The linear axis extending vertically through the centroid C is defined as "axis CY". In Figures 4, 6 to 7, and 9, the through-hole 200 and the connecting portion 5Ma are shown as dotted lines.

[0083] As shown in Figures 4 to 9, the bipolar plate 2 (the bipolar plate 2D on the back side of Figure 2) comprises a bipolar plate body 20 and a gasket 5. Note that, in terms of orientation of the paper, the front-to-back direction is reversed between Figures 4 to 6 (top views) and Figures 7 to 9 (bottom views).

[0084] [Dipole Plate Body 20] The dipole plate body 20 is a press-formed metal plate. As shown in Figures 5 and 8, the dipole plate body 20 has a rectangular shape when viewed from above (in a plan view), consisting of a pair of front and rear X sides 20X extending in the left-right direction (X direction) and a pair of left and right Y sides 20Y extending in the front-rear direction (Y direction). The X sides 20X are parallel to axis CX, and the Y sides 20Y are parallel to axis CY. A flange portion 20f is formed on the outer edge (the pair of X sides 20X and the pair of Y sides 20Y) of the dipole plate body 20. The flange portion 20f has a rectangular frame shape. As shown in Figure 15, the flange portion 20f bends vertically from the dipole plate body 20 (the part other than the flange portion 20f) and protrudes horizontally outward.

[0085] (Openings in the bipolar plate body 20) As shown in Figures 5 and 8, the bipolar plate body 20 has a plurality of openings (specifically, two first manifolds 20La, 20Rb, two second manifolds 20Lb, 20Ra, a plurality of through holes 200, and a pair of left and right rod insertion holes 202). Each of these openings penetrates the bipolar plate body 20 in the vertical direction. These openings are arranged symmetrically left to right with respect to the axis CY. Also, these openings are arranged symmetrically front to back with respect to the axis CX.

[0086] The first manifold 20La is located at the front left corner of the bipolar plate body 20. The first manifold 20Rb is located at the rear right corner of the bipolar plate body 20 (diagonally opposite the first manifold 20La with respect to the center of gravity C). Water (the raw material for electrolysis) flows through the first manifold 20Rb as the first fluid L1. Water containing oxygen (the product of electrolysis) flows through the first manifold 20La as the first fluid L1.

[0087] The second manifold 20Lb is located at the left rear corner of the bipolar plate body 20. The second manifold 20Ra is located at the right front corner of the bipolar plate body 20 (diagonally opposite the second manifold 20Lb with respect to the center of gravity C). Hydrogen (a product of electrolysis) flows as the second fluid L2 through the second manifolds 20Lb and 20Ra. The second manifold 20Ra is sealed.

[0088] In this manner, the water electrolyzer 9 generates oxygen (first fluid L1 in the first manifold 20La) and hydrogen (second fluid L2 in the second manifold 20Lb) from water (first fluid L1 in the first manifold 20Rb) through electrolysis.

[0089] As shown in Figures 4 and 7, the multiple through holes 200 are located on the outer ring (unsealed side, atmospheric side) of the front first seal portion 52U, front second seal portion 53U, back first seal portion 52D, and back second seal portion 53D, as viewed from above. Specifically, the through holes 200 are located on the outer ring of the front first seal portion 52U, the front second seal portion 53U, the back first seal portion 52D, and the back second seal portion 53D, as viewed from above. In other words, the multiple through holes 200 are located on the outer ring of all seal portions (front first seal portion 52U, front second seal portion 53U, back first seal portion 52D, and back second seal portion 53D), as viewed from above. The left and right pair of rod insertion holes 202 are located on the axis CX, near the left and right pair of Y sides 20Y. A tie rod 92 is inserted through the rod insertion hole 202.

[0090] (Configuration of the upper surface 20U of the bipolar plate body 20) As shown in Figure 5, the upper surface (surface) 20U of the bipolar plate body 20 has a front-side flow path area 21U and a front-side arrangement portion 25U. The front-side flow path area 21U has a rectangular shape. The front-side flow path area 21U is located inside the first manifolds 20La, 20Rb and the second manifolds 20Lb, 20Ra in the left-right direction. The first fluid L1 flows through the front-side flow path area 21U. The front-side flow path area 21U has a rectangular front-side flow path uneven portion 22U.

[0091] As shown in Figures 4, 7, and 11-12, the surface channel uneven portion 22U has an uneven shape (rectangular wave shape) with vertical undulations. Specifically, the surface channel uneven portion 22U comprises a plurality of surface protrusions 220U and a plurality of surface grooves 221U. The surface protrusions 220U extend in the left-right direction, except for the portion included in the surface inclined portion 23U, which will be described later. The plurality of surface protrusions 220U are arranged in the front-rear direction. The surface grooves 221U extend in the left-right direction, except for the portion included in the surface inclined portion 23U, which will be described later. The surface grooves 221U are partitioned between adjacent pairs of surface protrusions 220U. The plurality of surface grooves 221U are arranged in the front-rear direction. The surface protrusions 220U project upward relative to the surface grooves 221U.

[0092] As shown in Figures 4, 7, and 11, the front-side inclined portion 23U is located in the left-right center of the front-side flow channel uneven portion 22U. When viewed from above, the front-side inclined portion 23U has a band shape that overlaps with the center of gravity C and axis CY. Of the aforementioned front-side protrusions 220U and front-side grooves 221U, the portions located on the front-side inclined portion 23U extend in the direction of inclination (right front - left rear direction) when viewed from above.

[0093] As shown in Figures 4 and 5, the front-side arrangement portion 25U is provided with a front-side gasket uneven portion 26U. The front-side gasket uneven portion 26U extends so as to overlap with the entire sealing portion (front-side first sealing portion 52U, front-side second sealing portion 53U, back-side first sealing portion 52D, back-side second sealing portion 53D) when viewed from the front-back direction. The front-side gasket uneven portion 26U surrounds the first manifold 20La, 20Rb, the second manifold 20Lb, 20Ra, the front-side flow path area 21U, and the back-side flow path area 21D.

[0094] As shown in Figures 15 to 16(B), the surface gasket surface ridge 26U has a ridged shape (triangular wave shape) with vertical undulations. Specifically, the surface gasket surface ridge 26U comprises a surface convex portion 260U and a surface groove portion 261U. The surface convex portion 260U and the surface groove portion 261U are adjacent to each other. The surface convex portion 260U protrudes upward relative to the surface groove portion 261U.

[0095] (Configuration of the lower surface 20D side of the bipolar plate body 20) The bipolar plate body 20 is a press-formed metal plate. Therefore, the configuration (shape, arrangement, etc.) of the lower surface (back surface) 20D side and the configuration of the upper surface 20U side described above are symmetrical in the vertical direction. The configuration of the lower surface 20D side will be briefly described below.

[0096] As shown in Figure 8, the lower surface 20D of the bipolar plate body 20 has a back-side flow path area 21D and a back-side arrangement portion 25D. The back-side flow path area 21D overlaps with the front-side flow path area 21U when viewed from the vertical direction. The second fluid L2 flows in the back-side flow path area 21D. The back-side flow path area 21D has a back-side flow path uneven portion 22D. As shown in Figures 11 to 12, the back-side flow path uneven portion 22D and the front-side flow path uneven portion 22U are arranged opposite each other in the vertical direction. The back-side flow path uneven portion 22D and the front-side flow path uneven portion 22U have a shape that is symmetrical to each other. Specifically, the back-side flow path uneven portion 22D has a plurality of back-side protrusions 220D and a plurality of back-side grooves 221D. The back-side protrusions 220D overlap with the front-side grooves 221U when viewed from the vertical direction. The groove portion 221D on the back side overlaps with the protrusion portion 220U on the front side when viewed from above. The protrusion portion 220D on the back side protrudes downward relative to the groove portion 221D.

[0097] As shown in Figures 7 and 8, the back-side inclined portion 23D is located in the left-right center of the back-side flow channel uneven portion 22D. As shown in Figure 11, in a single bipolar plate 2, the back-side inclined portion 23D and the front-side inclined portion 23U are arranged opposite each other in the vertical direction. The back-side inclined portion 23D and the front-side inclined portion 23U have a shape that is symmetrical to each other. When viewed from the vertical direction, the back-side inclined portion 23D overlaps with the front-side inclined portion 23U. The back-side inclined portion 23D extends in the inclination direction (the same direction as the front-side inclined portion 23U).

[0098] As shown in Figures 16(A) to 16(B), the back-side configuration portion 25D overlaps with the front-side configuration portion 25U when viewed from the vertical direction. The back-side configuration portion 25D includes a back-side gasket uneven portion 26D. The back-side gasket uneven portion 26D overlaps with the front-side gasket uneven portion 26U when viewed from the vertical direction. The back-side gasket uneven portion 26D and the front-side gasket uneven portion 26U have a shape that is symmetrical to each other. Specifically, the back-side gasket uneven portion 26D includes a back-side protrusion 260D and a back-side groove portion 261D. The back-side protrusion 260D overlaps with the front-side groove portion 261U when viewed from the vertical direction. The back-side groove portion 261D overlaps with the front-side protrusion 260U when viewed from the vertical direction. The back side protrusion 260D protrudes downward relative to the back side groove 261D.

[0099] [Gasket 5] Gasket 5 is a single piece made of elastomer (for example, EPDM (ethylene propylene diene rubber)). As shown in Figures 4, 6-7, 9, 13-18, gasket 5 comprises a front gasket 5U, a back gasket 5D, a plurality of connecting parts 5Ma, and four covering parts 5Mb.

[0100] (Front gasket 5U) The front gasket 5U is located in the front mounting section 25U. The front gasket 5U comprises a front base layer 50U, two front connecting sections 51U, a front first sealing section 52U, and two front second sealing sections 53U. The front base layer 50U is laminated on the front mounting section 25U. Multiple front through holes 54U are provided in the front base layer 50U. The front through holes 54U penetrate the front base layer 50U in the vertical direction. The front through holes 54U are marks left by the front pins 800U of the insert molding die 8, which will be described later.

[0101] The front-side first seal portion 52U is laminated on the upper surface of the front-side base layer 50U. The front-side first seal portion 52U is positioned above the front-side gasket uneven portion 26U. The front-side first seal portion 52U comprehensively surrounds the first manifold 20La, 20Rb and the front-side flow path area 21U. When viewed from above, the front-side first seal portion 52U has an annular (endless annular) shape. As shown in Figures 15 to 16(A), the front-side first seal portion 52U is elastically in contact with the reference water electrolytic member 6M (water electrolytic member 6 laminated adjacent to the upper side of the back-side bipolar plate 2D).

[0102] The two front-side second seal portions 53U are laminated on the upper surface of the front-side base layer 50U. The two front-side second seal portions 53U are positioned above the front-side gasket uneven portion 26U. The two front-side second seal portions 53U individually surround the second manifolds 20Lb and 20Ra. When viewed from above, the front-side second seal portions 53U have an annular (endless annular) shape. Similar to the front-side first seal portion 52U, the front-side second seal portions 53U are elastically in contact with the reference water electrolysis member 6M.

[0103] The two front-side connecting portions 51U are formed in the front-side base layer 50U. The front-side connecting portions 51U connect the first manifolds 20La and 20Rb to the front-side flow path area 21U. The front-side connecting portions 51U have an uneven shape (rectangular wave shape) with vertical undulations.

[0104] Specifically, as shown in Figure 13, the front connecting portion 51U comprises a plurality of front protrusions 510U and a plurality of front grooves 511U. The front protrusions 510U extend in the left-right direction. The plurality of front protrusions 510U are arranged in the front-rear direction. The front grooves 511U extend in the left-right direction. The front grooves 511U are flush with the front base layer 50U. The front grooves 511U are partitioned between adjacent pairs of front protrusions 510U. The plurality of front grooves 511U are arranged in the front-rear direction. The first fluid L1 flows through the front grooves 511U.

[0105] As shown in Figures 15 and 16(B), the front projection 510U protrudes upward relative to the front groove 511U. The front projection 510U is elastically in contact with the reference water electrolysis member 6M.

[0106] (Back gasket 5D) The back gasket 5D and the front gasket 5U described above have inversely symmetrical shapes. As shown in Figures 6 and 9 (in terms of the orientation of the paper, the front and back directions of Figures 6 and 9 are opposite to each other), the configuration (shape, arrangement, etc.) of the back gasket 5D is the same as the configuration of the front gasket 5U described above, but inverted vertically with respect to the X side 20X (or axis CX) or the Y side 20Y (or axis CY).

[0107] As shown in Figures 7 to 9 and 14 to 16, the back gasket 5D is positioned in the back mounting section 25D. The back gasket 5D comprises a back base layer 50D, two back connecting sections 51D, two back first sealing sections 52D, and a back second sealing section 53D. The back base layer 50D is laminated on the back mounting section 25D. Multiple back through holes 54D are provided in the back base layer 50D. The back through holes 54D penetrate the back base layer 50D in the vertical direction. The back through holes 54D are marks left by the back pins 800D of the insert molding die 8, which will be described later.

[0108] The two back-side first seal portions 52D are laminated on the lower surface of the back-side base layer 50D. The two back-side first seal portions 52D are located below the back-side gasket uneven portion 26D. The two back-side first seal portions 52D individually surround the first manifolds 20La and 20Rb. When viewed from above, the back-side first seal portions 52D have an annular (endless annular) shape. As shown in Figures 15 and 16(B), the back-side first seal portions 52D are elastically in contact with the water electrolysis member 6 (shown by a dotted line in Figure 16(B)) which is laminated adjacent to the lower side of the back-side bipolar plate 2D.

[0109] The second seal portion 53D on the back side is laminated on the lower surface of the base layer 50D on the back side. The second seal portion 53D on the back side comprehensively surrounds the second manifold 20Lb, 20Ra and the back side flow path area 21D. The second seal portion 53D on the back side is located below the back side gasket uneven portion 26D. When viewed from the top and bottom, the second seal portion 53D on the back side has an annular (endless annular) shape. As shown in Figures 15 and 16(B), the second seal portion 53D on the back side is elastically in contact with the water electrolysis member 6 which is laminated adjacent to the lower side of the back side bipolar plate 2D.

[0110] As shown in Figures 7, 9, and 17, the two rear-side connecting portions 51D are formed in the rear-side base layer 50D. The rear-side connecting portions 51D connect the second manifolds 20Lb and 20Ra to the rear-side flow path area 21D. The rear-side connecting portions 51D have an uneven shape (rectangular wave shape) with vertical undulations.

[0111] Specifically, the back-side connecting portion 51D comprises a plurality of back-side protrusions 510D and a plurality of back-side grooves 511D. Similar to the front-side connecting portion 51U shown in Figure 13, the back-side protrusions 510D extend in the left-right direction. The plurality of back-side protrusions 510D are arranged in the front-rear direction. The back-side grooves 511D extend in the left-right direction. The back-side grooves 511D are flush with the back-side base layer 50D. The back-side grooves 511D are partitioned between adjacent pairs of back-side protrusions 510D. The plurality of back-side grooves 511D are arranged in the front-rear direction. The second fluid L2 flows through the back-side grooves 511D.

[0112] In Figures 15 and 16(B), the back side protrusion 510D is vertically symmetrical to the front side protrusion 510U, and protrudes downward relative to the back side groove 511D. The back side protrusion 510D is elastically in contact with the water electrolysis member 6, which is laminated adjacent to the lower side of the back side bipolar plate 2D.

[0113] (Regarding the vertical overlap between the front gasket 5U and the back gasket 5D) As shown in Figures 17 and 18, when viewed from the vertical direction, the outer edge of the front gasket 5U (specifically, the outer edge of the front base layer 50U) 5Ua and the outer edge of the back gasket 5D (specifically, the outer edge of the back base layer 50D) 5Da overlap. In addition, the inner edge of the front gasket 5U (specifically, the inner edge of the front base layer 50U) 5Ub and the inner edge of the back gasket 5D (specifically, the inner edge of the back base layer 50D) 5Db overlap. Thus, when viewed from the vertical direction, the silhouette (overall shape) of the front gasket 5U and the silhouette of the back gasket 5D overlap.

[0114] As shown by hatching in Figures 17 and 18, when viewed from above, multiple gasket overlapping sections O are arranged between the front gasket 5U and the back gasket 5D. In the gasket overlapping sections O, the gasket material (elastomer) of the gasket 5 is stacked vertically with the bipolar plate body 20 in between. In addition, in the laminate 91 shown in Figure 1, the gasket overlapping sections O of multiple bipolar plates 2 are stacked vertically.

[0115] (Connecting portion 5Ma) As shown in Figures 4, 6-7, 9, and 13-15, the connecting portion 5Ma is filled and positioned within the through hole 200. The connecting portion 5Ma connects the front base layer 50U of the front gasket 5U and the back base layer 50D of the back gasket 5D in the vertical direction.

[0116] (Coating portion 5Mb) As shown in Figures 4, 6-7, 9, and 13-15, the coating portion 5Mb is laminated on the inner circumferential surface of each manifold (first manifold 20La, 20Rb, second manifold 20Lb, 20Ra). The coating portion 5Mb completely covers the inner circumferential surface of each manifold. The coating portion 5Mb connects the front base layer 50U of the front gasket 5U and the back base layer 50D of the back gasket 5D in the vertical direction. The front gasket 5U, the back gasket 5D, the connecting portion 5Ma, and the coating portion 5Mb are integrally connected.

[0117] <Water Electrolysis Member 6> Next, the configuration of the water electrolysis member 6 will be described. As shown in Figures 10 and 15, the water electrolysis member 6 comprises an electrolysis unit 60 and a frame unit 61. The electrolysis unit 60 comprises an electrolyte membrane 600, a front catalyst layer 601U, a back catalyst layer 601D, a front diffusion layer 602U, and a back diffusion layer 602D. The electrolyte membrane 600 has a rectangular shape when viewed from the front or back direction. The electrolyte membrane 600 is an anion exchange membrane. The front catalyst layer 601U is laminated on the upper surface of the electrolyte membrane 600, and the back catalyst layer 601D is laminated on the lower surface of the electrolyte membrane 600. The front diffusion layer 602U is laminated on the upper surface of the front catalyst layer 601U, and the back diffusion layer 602D is laminated on the lower surface of the back catalyst layer 601D.

[0118] The frame portion 61 has a rectangular frame shape when viewed from the front and back. The frame portion 61 surrounds the electrolytic unit 60 from the horizontal outside. The frame portion 61 has higher rigidity than the electrolyte membrane 600. The frame portion 61 has multiple openings that communicate vertically with multiple openings in the bipolar plate 2 (two first manifolds 20La, 20Rb, two second manifolds 20Lb, 20Ra, and a pair of left and right rod insertion holes 202). Each of these openings penetrates the frame portion 61 in the vertical direction.

[0119] <Operation of the water electrolysis device 9> Next, the operation of the water electrolysis device 9 of this embodiment will be described. The laminated body 91 shown in Figure 1 has four openings (not shown) that extend in the vertical direction. The four openings communicate with four manifolds (first manifolds 20La, 20Rb, second manifolds 20Lb, 20Ra) of the bipolar plate 2 shown in Figure 2.

[0120] The operation of the water electrolysis device 9 will be explained below, focusing on the reference water electrolysis member 6M, the back-side bipolar plate 2D, and the front-side bipolar plate 2U shown in Figure 15, as representatives of each layer of the laminate 91. Water is supplied to the first manifold 20Rb of the back-side bipolar plate 2D through the opening of the laminate 91. As shown in Figures 1 and 15, the water flows from the first manifold 20Rb of the back-side bipolar plate 2D, through the front-side connecting portion 51U, into the front-side flow path area 21U. The electrolysis unit 60 of the reference water electrolysis member 6M is located above the front-side flow path area 21U of the back-side bipolar plate 2D. The electrolyte membrane 600 of the electrolysis unit 60 is an anion exchange membrane. A portion of the water in the front-side flow path area 21U passes through the electrolyte membrane 600 from bottom to top, moving from the front-side flow path area 21U of the back-side bipolar plate 2D to the back-side flow path area 21D of the front-side bipolar plate 2U.

[0121] In the presence of this water, the reaction (electrolysis) shown in (Equation 1) below occurs in the back channel area 21D (cathode side) of the front bipolar plate 2U. Electrons are supplied by the reaction shown in (Equation 2), which will be described later. 2H ２ O + 2e － →H ２ +2OH － ... (Equation 1) As shown in (Equation 1), hydrogen and hydroxide ions are generated from water by electrolysis. Of these, hydrogen flows out of the water electrolysis device 9 from the back channel area 21D of the front bipolar plate 2U, through the back connecting section 51D and the second manifold 20Lb.

[0122] Meanwhile, hydroxide ions (carriers for the electrode reaction) pass through the electrolyte membrane 600 of the electrolytic section 60 of the reference water electrolytic member 6M from top to bottom, moving from the back channel area 21D of the front bipolar plate 2U to the front channel area 21U of the back bipolar plate 2D.

[0123] The hydroxide ions cause the following reaction (Equation 2) to occur in the front channel area 21U (anode side) of the back bipolar plate 2D: 4OH － →O ２ +2H ２ O+4e － ... (Equation 2) That is, oxygen and water are generated from hydroxide ions. The oxygen and water are taken out of the water electrolysis device 9 from the front channel area 21U of the back bipolar plate 2D via the front connecting section 51U and the first manifold 20La. The electrons generated by the reaction shown in (Equation 2) are supplied to the back channel area 21D of the front bipolar plate 2U via an external power supply (not shown in the figure) and used for the electrolysis shown in (Equation 1).

[0124] <Manufacturing Method for Bipolar Plate 2 with Double-Sided Gaskets> Next, the manufacturing method for the bipolar plate 2 will be described. The manufacturing method for the bipolar plate 2 includes a press molding step and an insert molding step.

[0125] [Press Forming Process] This process comprises a sheet deformation process, a first punching process, and a second punching process. Figure 19(A) shows a partial vertical cross-sectional view of the press forming die during the early sheet deformation process of the press forming process for manufacturing a bipolar plate. Figure 19(B) shows a partial vertical cross-sectional view of the press forming die during the later sheet deformation process. Figure 19(C) shows a partial vertical cross-sectional view of the bipolar plate body during the first punching process of the press forming process. Figure 19(D) shows a partial vertical cross-sectional view of the bipolar plate body during the second punching process of the press forming process. Note that the parts shown in Figures 19(A) to 19(D) all correspond to Figure 15 (the XV-XV direction cross-sectional view in Figure 13).

[0126] (Press forming die 7) As shown in Figures 19(A) to 19(B), the press forming die 7 comprises an upper die (movable die) 7U and a lower die (fixed die) 7D. The upper die 7U is positioned above the lower die 7D. The upper die 7U can move closer to and further away from the lower die 7D in the vertical direction (the opening and closing direction of the press forming die 7). A strip-shaped sheet material (raw material) W is positioned between the upper die 7U and the lower die 7D. The sheet material W is included in the concept of "intermediate product of the bipolar plate body" in this disclosure. The sheet material W is conveyed in the left-right direction (conveying direction) at a predetermined pitch.

[0127] The front molding section 70U is positioned on the lower surface (molding surface) of the upper mold 7U. The front molding section 70U and the upper surface 20U of the bipolar plate body 20 (specifically, the front flow channel area 21U having the front flow channel irregularities 22U, the front arrangement section 25U having the front gasket irregularities 26U, and the flange section 20f) have a shape that is symmetrical to each other.

[0128] A rear molding section 70D is positioned on the upper surface (molding surface) of the lower mold 7D. The rear molding section 70D and the front molding section 70U have a mold-symmetrical shape. The rear molding section 70D and the front molding section 70U are positioned opposite each other in the vertical direction. The rear molding section 70D and the lower surface 20D of the bipolar plate body 20 (specifically, the rear flow channel area 21D having rear flow channel irregularities 22D, the rear arrangement section 25D having rear gasket irregularities 26D, and the flange section 20f) have a mold-symmetrical shape.

[0129] (Sheet deformation process) In this process, the press molding die 7 described above is used to impart the uneven shape of the bipolar plate body 20 to the sheet metal W being transported at a predetermined pitch at predetermined intervals. First, as shown in Figure 19(A), the sheet metal W is stopped between the lower die 7D and the upper die 7U of the press molding die 7 in the open state. Next, as shown in Figure 19(B), the die is clamped, and the sheet metal W is sandwiched from above and below by the lower die 7D (back side molding part 70D) and the upper die 7U (front side molding part 70U). This sandwiching process forms the front side flow channel uneven part 22U on the upper surface of the sheet metal W in the part corresponding to the front side flow channel area 21U. Also, the front side gasket uneven part 26U is formed in the part corresponding to the front side arrangement part 25U. Similarly, the back side flow channel uneven part 22D is formed on the lower surface of the sheet metal W in the part corresponding to the back side flow channel area 21D. Furthermore, a rear gasket recessed portion 26D is formed in the portion corresponding to the rear mounting portion 25D. Also, a flange portion 20f is formed.

[0130] (First punching process) In this process, a first punching process is performed on the sheet material W after the sheet deformation process using a first punching die (not shown) located to the right of the press forming die 7 (downstream in the conveying direction of the sheet material W). As shown in Figure 19(C), the first punching process creates a first manifold 20La, 20Rb, a second manifold 20Lb, 20Ra, and a through hole 200 at predetermined positions on the sheet material W.

[0131] (Second punching process) In this process, a second punching process is performed on the sheet material W after the first punching process using a second punching die (not shown) located to the right of the first punching die. As shown in Figure 19(D), the second punching process removes the bipolar plate body 20 of a predetermined shape from the sheet material W.

[0132] As explained above, in the press forming process (sheet deformation process, first punching process, second punching process), the bipolar plate body 20 is continuously manufactured from sheet material W that is conveyed at a predetermined pitch.

[0133] [Insert Molding Process] This process comprises a placement process, a raw material injection process, and a curing process. An insert molding die is used in this process. Figure 20(A) shows a partial vertical cross-sectional view of the insert molding die during the placement process of the insert molding process for manufacturing a bipolar plate. Figure 20(B) shows a partial vertical cross-sectional view of the insert molding die during the raw material injection process of the same insert molding process. Figure 21(A) shows a partial vertical cross-sectional view of the insert molding die during the early stage of the curing process of the same insert molding process. Figure 21(B) shows a partial vertical cross-sectional view of the insert molding die during the later stage of the curing process. Note that the parts of the insert molding die shown in Figures 20(A) to 21(B) all correspond to Figure 15 (the XV-XV cross-sectional view in Figure 13), similar to Figures 19(A) to 19(B).

[0134] In Figures 20(A) to 21(B), the reference numerals for cavities and molded parts are the same as the reference numerals for the gaskets formed by those cavities and molded parts, with a "c" added. For example, the reference numeral "5c" for cavity 5c is the same as the reference numeral "5" for gasket 5 formed by cavity 5c, with a "c" added.

[0135] (Insert molding die 8) As shown in Figures 20(A) to 21(B), the insert molding die 8 comprises an upper die (movable die) 8U and a lower die (fixed die) 8D. The upper die 8U is positioned above the lower die 8D. The upper die 8U can move closer to and further away from the lower die 8D in the vertical direction (the opening and closing direction of the insert molding die 8).

[0136] Multiple front-side pins 800U are provided protruding downwards (towards the lower mold 8D) from the lower surface (molding surface) of the upper mold 8U. Additionally, four gates G for supplying raw material E are provided on the lower surface of the upper mold 8U. Multiple back-side pins 800D are provided protruding upwards (towards the upper mold 8U) from the upper surface (molding surface) of the lower mold 8D. The back-side pins 800D and the front-side pins 800U are opposed to each other in the vertical direction.

[0137] A cavity 5c is partitioned between the upper mold 8U and the lower mold 8D. The cavity 5c corresponds to the gasket 5. The cavity 5c comprises a front molding section 5Uc, a back molding section 5Dc, multiple connecting molding sections 5Mac, and four covering molding sections 5Mbc. The cavity 5c also comprises four scrap generating sections Sc. The scrap generating sections Sc are located inside the covering molding sections 5Mbc.

[0138] The front molding section 5Uc is a space for molding the front gasket 5U. The front molding section 5Uc comprises a front base layer molding section 50Uc, two front connecting section molding sections, a front first molding section 52Uc, and two front second molding sections. The front base layer molding section 50Uc corresponds to the front base layer 50U, the front connecting section molding section corresponds to the front connecting section 51U, the front first molding section 52Uc corresponds to the front first seal section 52U, and the front second molding section corresponds to the front second seal section 53U.

[0139] Similarly, the back molding section 5Dc is a space for molding the back gasket 5D. The back molding section 5Dc comprises a back base layer molding section 50Dc, two back connecting section molding sections, a back first molding section 52Dc, and two back second molding sections 53Dc. The back base layer molding section 50Dc corresponds to the back base layer 50D, the back connecting section molding section corresponds to the back connecting section 51D, the back first molding section 52Dc corresponds to the back first seal section 52D, and the back second molding section 53Dc corresponds to the back second seal section 53D.

[0140] Similarly, the connecting portion molding section 5Mac is a space for molding the connecting portion 5Ma, and the covering portion molding section 5Mbc is a space for molding the covering portion 5Mb. Scrap S is generated in the scrap generation section Sc.

[0141] (Placement Process) In this process, as shown in Figure 20(A), the bipolar plate body 20 manufactured in the press molding process is placed inside the mold of the insert molding die 8 in the open state. Specifically, the bipolar plate body 20 is placed at a predetermined position on the upper surface of the lower die 8D.

[0142] In addition, adhesive may be pre-applied to the parts of the bipolar plate body 20 where the gasket 5 is formed (for example, the front side arrangement part 25U, the back side arrangement part 25D, the inner circumferential surfaces of each manifold (first manifold 20La, 20Rb, second manifold 20Lb, 20Ra), the inner circumferential surface of the through hole 200, etc.). However, in this process, no such adhesive (adhesive for bonding the gasket 5) is applied to the bipolar plate body 20. However, the insert molding step of the manufacturing method of a bipolar plate with double-sided gaskets according to this disclosure does not specifically exclude the "form in which adhesive is pre-applied to the parts of the bipolar plate body 20 where the gasket 5 is formed before the raw material injection step."

[0143] Next, as shown in Figure 20(B), the insert molding die 8 is clamped by bringing the upper die 8U into contact with the lower die 8D. The insert molding die 8 switches from the open state to the clamped state. In the clamped state, the gate G of the upper die 8U is located inside each manifold (inside the covering molding section 5Mbc). The gate G is located above the scrap generation section Sc. In the clamped state, the front pin 800U is in contact with a predetermined position on the upper surface 20U of the bipolar plate body 20, and the back pin 800D is in contact with a predetermined position on the lower surface 20D of the bipolar plate body 20. The cavity 5c is divided by the bipolar plate body 20 into an upper front molding section 5Uc and a lower back molding section 5Dc. However, the front molded portion 5Uc and the lower back molded portion 5Dc are in communication with each manifold and multiple through holes 200 of the bipolar plate body 20.

[0144] (Raw material injection process) In this process, as shown in Figure 20(B), liquid raw material E is injected from four gates G into each manifold (first manifold 20La, 20Rb, second manifold 20Lb, 20Ra) to fill the cavity 5c with raw material E.

[0145] In each manifold, the raw material E is injected from the gate G through the scrap generation section Sc into the coating molding section 5Mbc. Starting from the coating molding section 5Mbc, the raw material E is divided into the front molding section 5Uc and the back molding section 5Dc. The raw material E also flows freely between the front molding section 5Uc and the back molding section 5Dc through each manifold and multiple through holes 200. In this way, the raw material E fills the entire cavity 5c.

[0146] As described above, the front pin 800U is in contact with the upper surface 20U of the bipolar plate body 20, and the back pin 800D is in contact with the lower surface 20D of the bipolar plate body 20. Therefore, vibration (chatter) and deformation of the bipolar plate body 20 caused by the injection pressure of the raw material E are suppressed. Consequently, volume changes in the front molded portion 5Uc and the back molded portion 5Dc are suppressed.

[0147] (Curing process) In this process, as shown in Figure 21(A), the raw material E is cured by heating the insert molding die 8 in a predetermined temperature pattern (heating temperature, heating time). Next, as shown in Figure 21(B), the insert molding die 8 is switched from the clamped state to the open state, and the bipolar plate 2 is removed from inside the mold. After that, the scrap S is separated from the coated portion 5Mb.

[0148] As described above, in the insert molding process (placement process, raw material injection process, and curing process), the bipolar plate 2 is manufactured by molding and joining the gasket 5 to the bipolar plate body 20.

[0149] <Method for Manufacturing the Water Electrolyzer 9> Next, the method for manufacturing the water electrolyzer 9 will be described. The method for manufacturing the water electrolyzer 9 includes an inversion stacking step and a fastening step.

[0150] [Inverted Lamination Process] In this process, multiple bipolar plates 2 and multiple water electrolytic members 6 are alternately stacked in the vertical direction to produce a laminate 91. In this process, as shown in Figure 3, multiple bipolar plates 2 having the same configuration are stacked inverted vertically, one at a time (water electrolytic members 6 are not counted). For example, among multiple bipolar plates 2 arranged in the stacking direction (vertical direction), only the odd-numbered (or even-numbered) bipolar plates 2 counted from one end in the stacking direction are stacked inverted vertically.

[0151] Therefore, a pair of bipolar plates 2 adjacent to each other in the vertical direction with respect to the water electrolysis member 6 (for example, the front bipolar plate 2U and the back bipolar plate 2D shown in Figures 2 and 3) are stacked inverted vertically with respect to the X side 20X (or axis CX) or the Y side 20Y (or axis CY).

[0152] As a result of the manufacturing of the laminate 91 in this manner, as shown in Figures 2 and 11, when viewed from above, the inclined portions of the front bipolar plate 2U (front inclined portion 23U, back inclined portion 23D) and the inclined portion of the back bipolar plate 2D extend in different directions from each other. Specifically, when viewed from above, the inclined portions of the front bipolar plate 2U and the inclined portions of the back bipolar plate 2D intersect in an X shape.

[0153] [Fastening Process] In this process, first, a pair of end plates 90 are placed at both the upper and lower ends of the laminate 91. Next, the pair of end plates 90 and the laminate 91 are fastened together with a pair of tie rods 92. The tie rods 92 are inserted through the rod insertion holes 202 of the multiple bipolar plates 2. The tie rods 92 apply a fastening force (pressing force) F to the laminate 91 from the upper and lower directions. This fastening force F causes adjacent bipolar plates 2 and the water electrolysis member 6 to press against each other in the upper and lower directions.

[0154] <Effects and Effects> Next, the effects and effects of the double-sided gasketed bipolar plate of this embodiment, the water electrolysis apparatus equipped with the double-sided gasketed bipolar plate, the method for manufacturing the double-sided gasketed bipolar plate, and the method for manufacturing the water electrolysis apparatus equipped with the double-sided gasketed bipolar plate will be described.

[0155] As shown in Figures 5, 8, 12, and 19(A) to 19(D), the bipolar plate body 20 is a press-formed metal plate. Therefore, the front channel area 21U and front arrangement section 25U, and the back channel area 21D and back arrangement section 25D can be formed and arranged simultaneously on the bipolar plate body 20. Thus, the productivity of the bipolar plate 2 can be improved. Furthermore, when viewed from above, the front channel area 21U and the back channel area 21D can be arranged in a completely overlapping manner. Therefore, the horizontal positioning accuracy of the front channel area 21U and the back channel area 21D can be improved. The same applies to the front arrangement section 25U and the back arrangement section 25D.

[0156] Furthermore, the upper surface 20U and the lower surface 20D have shapes that are symmetrical to each other. For example, the convex parts of the upper surface 20U correspond to the concave parts of the lower surface 20D, and the concave parts of the upper surface 20U correspond to the convex parts of the lower surface 20D. Therefore, the front flow channel area 21U and the back flow channel area 21D can have shapes that are inverted vertically relative to each other. Similarly, the front arrangement part 25U and the back arrangement part 25D can have shapes that are inverted vertically relative to each other.

[0157] As shown in Figure 15, the bipolar plate body 20 is equipped with a frame-shaped flange portion 20f. The flange portion 20f bends vertically from the outer edge of the bipolar plate body 20 and protrudes horizontally outward. Therefore, even though multiple bipolar plates 2 are stacked alternately inverted vertically in the laminate 91 (see Figure 3), the vertical orientation of the bipolar plate 2 can be easily confirmed simply by checking the bending direction of the flange portion 20f of the bipolar plate 2. For example, the orientation of the front bipolar plate 2U (flange portion 20f bent downwards) and the back bipolar plate 2D (flange portion 20f bent upwards) shown in Figure 15 can be easily confirmed. Furthermore, when manufacturing the laminate 91, multiple bipolar plates 2 can be stacked easily and accurately.

[0158] Furthermore, a single bipolar plate body 20 can secure both a front-side flow path area 21U and a back-side flow path area 21D. Therefore, compared to using separate plate members for the front-side flow path area 21U and the back-side flow path area 21D, the number of parts in the water electrolysis device 9 can be reduced. In addition, the reduction in the number of parts can reduce the assembly man-hours for the water electrolysis device 9.

[0159] As shown in Figures 6, 9, and 17, when viewed from above, the shape of the front gasket 5U and the shape of the back gasket 5D when inverted vertically are identical. That is, in a single bipolar plate 2, the front gasket 5U and the back gasket 5D exhibit mutually inverted symmetrical shapes. Specifically, when the back gasket 5D is inverted vertically (rotated 180°) with respect to the X side 20X (or axis CX) or the Y side 20Y (or axis CY) and placed on top of the front gasket 5U, the shapes of the front gasket 5U and the back gasket 5D become identical. The same is true when the front gasket 5U is inverted vertically and placed on top of the back gasket 5D. Therefore, the shapes of the front gasket 5U and the back gasket 5D can be standardized. Consequently, the productivity of the bipolar plate 2 can be improved.

[0160] As shown in Figure 15, the front bipolar plate 2U and the back bipolar plate 2D are stacked inverted in the vertical direction. As described above, for the front bipolar plate 2U, the front gasket 5U and the back gasket 5D have inverted symmetrical shapes. The same applies to the back bipolar plate 2D. Therefore, when the front bipolar plate 2U and the back bipolar plate 2D are stacked inverted in the vertical direction, the shape of the front gasket 5U of the front bipolar plate 2U and the shape of the front gasket 5U of the back bipolar plate 2D coincide (they are geometrically congruent) when viewed from above. Similarly, the shape of the back gasket 5D of the front bipolar plate 2U and the shape of the back gasket 5D of the back bipolar plate 2D coincide when viewed from above. Thus, according to this embodiment, the stacked body 91 can be easily assembled by stacking the front bipolar plate 2U and the back bipolar plate 2D inverted in the vertical direction. Furthermore, the laminated structure 91 can be configured to provide pathways for the first fluid L1 and the second fluid L2.

[0161] As shown in Figures 4, 6-7, 9, 13, and 17-18, the front gasket 5U is provided with a front connecting portion 51U, and the back gasket 5D is provided with a back connecting portion 51D. The front connecting portion 51U ensures a flow path for the first fluid L1 between the first manifolds 20La, 20Rb and the front flow path area 21U. Furthermore, as shown in Figure 15, the front connecting portion 51U of the back bipolar plate 2D (specifically, the upper surface of the front convex portion 510U) elastically contacts the lower surface of the reference water electrolytic member 6M, thereby sealing the front connecting portion 51U.

[0162] Similarly, the rear connecting portion 51D ensures a flow path for the second fluid L2 between the second manifolds 20Lb, 20Ra and the rear flow path area 21D. Also, similar to the front connecting portion 51U of the rear bipolar plate 2D shown in Figure 15, the rear connecting portion 51D of the front bipolar plate 2U (specifically, the lower surface of the rear convex portion 510D) can be sealed by elastically contacting the upper surface of the reference water electrolysis member 6M.

[0163] Furthermore, the front gasket 5U is provided with a front connecting portion 51U, and the back gasket 5D is provided with a back connecting portion 51D. Therefore, it is not necessary to add a shape to the bipolar plate body 20 for securing a flow path (although it may be added if desired). Consequently, the degree of freedom in the shape of the bipolar plate body 20 can be increased.

[0164] As shown in Figures 15, 16(B) to 18, when viewed from above, at least a portion of the front-side connecting portion 51U of the back-side bipolar plate 2D and at least a portion of the back-side gasket 5D of the front-side bipolar plate 2U overlap with each other. This allows for increased shape stability of the laminate 91. Furthermore, the fastening force F applied to the laminate 91 from both the top and bottom sides is less likely to escape from the contact area between the front-side connecting portion 51U of the back-side bipolar plate 2D and the reference water electrolysis member 6M. This improves the sealing performance of the front-side connecting portion 51U.

[0165] Similar to the front-side connecting portion 51U of the back-side bipolar plate 2D, as shown in Figure 17, when viewed from the top and bottom, at least a portion of the back-side connecting portion 51D of the front-side bipolar plate 2U and at least a portion of the front-side gasket 5U of the back-side bipolar plate 2D overlap with each other. This allows for increased shape stability of the laminate 91. Furthermore, the fastening force F applied to the laminate 91 from both the top and bottom sides is less likely to escape from the contact area between the back-side connecting portion 51D of the front-side bipolar plate 2U and the reference water electrolysis member 6M. This improves the sealing performance of the back-side connecting portion 51D.

[0166] As shown in Figures 13, 15, and 17-18, the front groove portion 511U of the front connecting portion 51U is partitioned using the front base layer 50U and the front protrusion 510U. Similarly, the back groove portion 511D of the back connecting portion 51D is partitioned using the back base layer 50D and the back protrusion 510D. Therefore, it is not necessary to specifically provide the bipolar plate body 20 with a shape for securing the front groove portion 511U (although it may be done if desired). Consequently, the degree of freedom in the shape of the bipolar plate body 20 can be increased.

[0167] As shown in Figures 5, 8, and 15-16(B), the front-side mounting portion 25U has a front-side gasket uneven portion 26U having vertical undulations (front-side convex portion 260U and front-side groove portion 261U). The front-side gasket uneven portion 26U can suppress misalignment of the front-side gasket 5U relative to the front-side mounting portion 25U. Therefore, adhesive (specifically, adhesive for bonding the front-side gasket 5U to the front-side mounting portion 25U) is unnecessary. Consequently, during the manufacturing of the bipolar plate 2, bonding-related processes (for example, a cleaning process to clean the front-side mounting portion 25U, a coating process to apply adhesive to the front-side mounting portion 25U after cleaning, and an inspection process to check the condition of the adhesive after application) can be omitted. Furthermore, the front-side gasket uneven portion 26U has an uneven shape. Therefore, the bending rigidity of the bipolar plate body 20 can be improved.

[0168] Similarly, the rear side mounting portion 25D has a rear gasket uneven portion 26D having vertical undulations (rear side protrusions 260D and rear side grooves 261D). The rear gasket uneven portion 26D can suppress misalignment of the rear gasket 5D relative to the rear side mounting portion 25D. Therefore, adhesive is not required. Consequently, the bonding process can be omitted during the manufacturing of the bipolar plate 2. In addition, the rear gasket uneven portion 26D has an uneven shape. Therefore, the bending rigidity of the bipolar plate body 20 can be improved.

[0169] As shown in Figures 5, 8, and 15-16(B), the front gasket recessed portion 26U and the back gasket recessed portion 26D are arranged facing each other in the vertical direction. Furthermore, the front gasket recessed portion 26U and the back gasket recessed portion 26D have a shape that is symmetrical to each other. Therefore, the front gasket recessed portion 26U and the back gasket recessed portion 26D can be simultaneously molded and positioned on the bipolar plate body 20 by press molding. Consequently, the productivity of the bipolar plate 2 can be improved.

[0170] In particular, the configuration of this embodiment is suitable when the adhesive is weak against at least one of the properties of the first fluid L1 (alkaline, acidic, etc.) and the second fluid L2. By adopting this configuration, misalignment of the front gasket 5U relative to the front mounting portion 25U can be suppressed without using an adhesive. Similarly, misalignment of the back gasket 5D relative to the back mounting portion 25D can be suppressed without using an adhesive.

[0171] As shown in Figures 5 and 8, the gasket surface irregularities 26U and the gasket surface irregularities 26D are arranged along the entire sealing area (first sealing area 52U on the front side, second sealing area 53U on the front side, first sealing area 52D on the back side, and second sealing area 53D on the back side). Therefore, displacement of the entire sealing area of ​​the gasket 5 can be suppressed in particular. Consequently, the sealing performance of the entire sealing area can be improved.

[0172] As shown in Figure 15, the gasket 5 has a connecting portion 5Ma. The connecting portion 5Ma allows the front gasket 5U, the bipolar plate body 20, and the back gasket 5D to be integrated. Therefore, adhesive is not required. Accordingly, the bonding process can be omitted during the manufacturing of the bipolar plate 2. In particular, the bipolar plate 2 of this embodiment is suitable when the adhesive is weak against at least one of the liquid properties of the first fluid L1 and the second fluid L2. According to the bipolar plate 2 of this embodiment, separation of the front gasket 5U, the bipolar plate body 20, and the back gasket 5D can be suppressed even without using adhesive.

[0173] Furthermore, in the bipolar plate 2 of this embodiment, when viewed from the top and bottom, the through-hole 200 is located on the outer side of the entire sealing portion. Therefore, compared to the case where the through-hole 200 is located on the inner side of the entire sealing portion (first fluid L1 side, second fluid L2 side), leakage of the first fluid L1 and second fluid L2 through the through-hole 200 can be suppressed.

[0174] The bipolar plate body 20 shown in Figures 5 and 8 is made of metal. Therefore, the inner surfaces of the four manifolds (first manifold 20La, 20Rb, second manifold 20Lb, Ra) are also all made of metal. In this respect, as shown in Figure 15, according to the bipolar plate 2 of this embodiment, the inner surfaces of the manifolds are covered with an elastomer coating 5Mb. Therefore, the inner surfaces of the metal manifolds can be protected from the first fluid L1, the second fluid L2, and so on.

[0175] Furthermore, the gasket 5 has a covering portion 5Mb in addition to the connecting portion 5Ma described above. The covering portion 5Mb allows the front gasket 5U, the bipolar plate body 20, and the back gasket 5D to be integrated. Therefore, adhesive is not required. Accordingly, the bonding process can be omitted during the manufacturing of the bipolar plate 2. In particular, the bipolar plate 2 of this embodiment is suitable when the adhesive is weak against at least one of the liquid properties of the first fluid L1 and the second fluid L2. According to the bipolar plate 2 of this embodiment, separation of the front gasket 5U, the bipolar plate body 20, and the back gasket 5D can be suppressed without using adhesive.

[0176] As shown in Figures 2 to 5 and Figures 11 to 12, the front channel area 21U has a front channel uneven portion 22U that has vertical undulations. The front channel uneven portion 22U can guide the flow of the first fluid L1 in the direction of extension of the front channel uneven portion 22U (left-right direction). Therefore, variations in the flow of the first fluid L1 (turbulence, etc.) can be suppressed. Consequently, the reaction efficiency of water electrolysis (electrolysis) can be improved. In addition, the front channel uneven portion 22U has an uneven shape. Therefore, the bending rigidity of the bipolar plate body 20 can be improved.

[0177] Similarly, as shown in Figures 7-8 and 11-12, the back channel area 21D has a back channel uneven portion 22D having vertical undulations. The back channel uneven portion 22D guides the flow of the second fluid L2 in the direction of extension of the back channel uneven portion 22D (left-right direction) and suppresses variations in the flow. This improves the reaction efficiency of water electrolysis. Furthermore, the back channel uneven portion 22D has an uneven shape. This improves the bending rigidity of the bipolar plate body 20.

[0178] As shown in Figure 11, in any single bipolar plate 2, the front-side inclined portion 23U and the back-side inclined portion 23D extend in the same direction (inclination direction). Furthermore, as shown in Figure 2, the front-side bipolar plate 2U and the back-side bipolar plate 2D are stacked inverted vertically with the reference water electrolytic member 6M in between, using the X-side 20X or Y-side 20Y as a reference. Therefore, the back-side inclined portion 23D of the front-side bipolar plate 2U and the front-side inclined portion 23U of the back-side bipolar plate 2D can be made to extend in different directions. Specifically, the inclined portion of the back-side bipolar plate 2D (front-side inclined portion 23U, back-side inclined portion 23D), shown by a solid line in Figure 11, and the inclined portion of the front-side bipolar plate 2U, shown by a dotted line in Figure 11, can be made to intersect in an X-shape when viewed from above. Therefore, interlocking can be suppressed. Thus, deformation of the reference water electrolytic member 6M caused by interlocking can be suppressed.

[0179] As shown in Figure 11, focusing on an arbitrary and single bipolar plate 2, when viewed from the top and bottom, the front-side inclined portion 23U and the back-side inclined portion 23D extend in the same direction. By stacking multiple bipolar plates 2, with every other plate inverted vertically (see Figure 3), the back-side inclined portion 23D of the front-side bipolar plate 2U and the front-side inclined portion 23U of the back-side bipolar plate 2D can be made to extend in different directions when viewed from the top and bottom. For example, among all the bipolar plates 2 constituting the laminate 91, only the bipolar plates 2 corresponding to odd-numbered positions when counted from the top end (one end in the stacking direction) may be stacked inverted vertically. Alternatively, only the bipolar plates 2 corresponding to even-numbered positions when counted from the top end may be stacked inverted vertically. In this way, with the bipolar plates 2 of this embodiment, interlocking can be easily suppressed simply by devising a method for stacking the bipolar plates 2.

[0180] As shown in Figure 11, there is a portion between the back surface shape of the bipolar plate body 20 of the front bipolar plate 2U and the front surface shape of the bipolar plate body 20 of the back bipolar plate 2D that does not exhibit a symmetrical shape. Specifically, the inclined portion 23D on the back of the front bipolar plate 2U, shown by a dotted line in Figure 11, and the inclined portion 23U on the front of the back bipolar plate 2D, shown by a solid line in Figure 11, intersect in an X shape when viewed from above. In this way, the bottom surface shape of the bipolar plate body 20 of the front bipolar plate 2U and the top surface shape of the bipolar plate body 20 of the back bipolar plate 2D exhibit a symmetrical shape with respect to each other. Therefore, as shown in Figure 2, it is possible to suppress the complete symmetry between the bottom surface shape of the front bipolar plate 2U and the top surface shape of the back bipolar plate 2D, which is laminated next to the front bipolar plate 2U on the underside with the reference water electrolytic member 6M in between (facing each other with the reference water electrolytic member 6M in between). Therefore, it is possible to suppress the fitting in. Thus, it is possible to suppress the deformation of the reference water electrolysis member 6M caused by fitting in.

[0181] The electrolyte membrane 600 shown in Figure 15 is an anion exchange membrane. Therefore, hydroxide ions (carriers for the electrode reaction) can be conducted via the electrolyte membrane 600 from the back channel area 21D of the front bipolar plate 2U (channel area for the second fluid L2 on the cathode side) to the front channel area 21U of the back bipolar plate 2D (channel area for the first fluid L1 on the anode side).

[0182] Furthermore, aqueous solutions of hydroxide ions are alkaline. Therefore, acidic dissolution of the catalysts in the front catalyst layer 601U and the back catalyst layer 601D shown in Figure 15 is unlikely. Consequently, non-precious metal materials can be used as catalysts. Thus, the manufacturing cost of the water electrolysis device 9 can be reduced.

[0183] As shown in Figures 10 and 15, the water electrolysis member 6 has a frame portion 61 that surrounds the electrolysis unit 60 and has higher rigidity than the electrolyte membrane 600. As shown in Figures 1 and 15, the fastening force F is applied mainly to the frame portion 61 of the water electrolysis member 6 via the front gasket 5U and the back gasket 5D. Therefore, it is possible to suppress the excessive application of the fastening force F to the electrolysis unit 60. Consequently, the shape stability of the electrolysis unit 60 (electrolyte membrane 600, front catalyst layer 601U, front diffusion layer 602U, back catalyst layer 601D, back diffusion layer 602D, etc.) can be increased.

[0184] The manufacturing method for the bipolar plate 2 of this embodiment includes a press molding step shown in Figures 19(A) to 19(D) and an insert molding step shown in Figures 20(A) to 21(B). Of these, the press molding step allows the first manifold 20La, 20Rb, the second manifold 20Lb, 20Ra, the front flow path area 21U, the front arrangement portion 25U, the back flow path area 21D, and the back arrangement portion 25D to be simultaneously molded and arranged on the bipolar plate body 20. Furthermore, the insert molding step allows the gasket 5 to be integrally molded and the gasket 5 to be joined to the bipolar plate body 20. Thus, according to the manufacturing method for the bipolar plate 2 of this embodiment, the bipolar plate 2 can be efficiently manufactured with fewer steps.

[0185] As shown in Figure 20(B), according to the manufacturing method of the bipolar plate 2 of this embodiment (raw material injection step of the insert molding process), each manifold (first manifold 20La, 20Rb, second manifold 20Lb, 20Ra) can be used as the raw material injection section into the cavity 5c. Therefore, the structure of the insert molding die 8 is simplified compared to the case in which a gate is arranged separately from the manifolds in the insert molding die 8.

[0186] As shown in Figure 19(B), according to the manufacturing method of the bipolar plate 2 of this embodiment (plate deformation process of the press molding process), the plate material W (intermediate product of the bipolar plate body 20) is sandwiched between the front molding section 70U and the back molding section 70D, thereby forming the front gasket uneven portion 26U on the front placement section 25U and the back gasket uneven portion 26D on the back placement section 25D. Therefore, the front gasket uneven portion 26U and the back gasket uneven portion 26D can be formed and positioned simultaneously.

[0187] As shown in Figure 20(B), according to the manufacturing method (insert molding process) of the bipolar plate 2 of this embodiment, in the raw material injection process, the raw material E can be distributed to both the upper and lower sides of the bipolar plate body 20 through the through hole 200. Furthermore, the raw material E can be distributed to the front side first molding section 52Uc (front side first seal section 52U) and the front side second molding section (front side second seal section 53U) via the front side base layer molding section 50Uc. In addition, the raw material E can be distributed to the back side first molding section 52Dc (back side first seal section 52D) and the back side second molding section 53Dc (back side second seal section 53D) via the back side base layer molding section 50Dc.

[0188] In the manufacturing method of the water electrolysis device 9 of this embodiment, a laminate 91 is manufactured in the inversion lamination process, and in the fastening process, the laminate 91 is sandwiched between end plates 90 from both the upper and lower sides, thereby pressing the bipolar plate 2 and the water electrolysis member 6 into contact. Therefore, the water electrolysis device 9 can be easily manufactured. Furthermore, the fastening process improves the sealing performance of the front side first seal portion 52U, the front side second seal portion 53U, the back side first seal portion 52D, and the back side second seal portion 53D.

[0189] <Other> The embodiments of the double-sided gasketed bipolar plate, the water electrolysis apparatus equipped with the double-sided gasketed bipolar plate, the method for manufacturing the double-sided gasketed bipolar plate, and the method for manufacturing the water electrolysis apparatus equipped with the double-sided gasketed bipolar plate have been described above. However, the embodiments are not particularly limited to the above forms. Various modified and improved forms can be implemented by those skilled in the art.

[0190] Figures 22(A) to 22(D) show schematic top views of bipolar plates with double-sided gaskets for other embodiments (1 to 4). The same reference numerals are used for parts corresponding to those in Figure 4. The front connecting portion 51U, the front first sealing portion 52U, the front second sealing portion 53U, the front flow path area 21U, the front flow path uneven portion 22U, and the front inclined portion 23U are also shown in a simplified manner.

[0191] As shown in Figure 22(A), a front-side inclined portion 23U may be arranged in a part of the front-side flow channel area 21U. Multiple front-side inclined portions 23U may also be arranged. The same applies to the back-side inclined portion. As shown in Figure 22(B), a single front-side inclined portion 23U may be arranged across the entire front-side flow channel area 21U. The same applies to the back-side inclined portion.

[0192] As shown in Figures 22(A) to 22(B), the number, position, and inclination direction of the front-side inclined portions 23U (more specifically, the extension direction of the portion of the front-side flow channel irregularities 22U (front-side protrusions, front-side grooves) that is located on the front-side inclined portions 23U; for example, left-front to right-rear direction, right-front to left-rear direction, etc.) are not particularly limited. Also, the front-side inclined portions 23U may extend in a straight line or in a curved shape when viewed from the vertical direction. The same applies to the back-side inclined portions.

[0193] As shown in Figure 22(C), the front-side inclined portion does not necessarily have to be arranged in the front-side flow channel area 21U. The arrangement density (pitch) of the uneven shape of the front-side flow channel uneven portion 22U (specifically, the front-side protrusions and grooves extending in the left-right direction) may be set to be sparse on the front side and dense on the rear side, with the axis CX in between. Conversely, the front side may be dense and the rear side may be sparse, with the axis CX in between. In this case, overlapping can be suppressed by stacking multiple bipolar plates 2 alternately, with the X side 20X (or axis CX) as the reference, inverted vertically. The same applies to the back-side flow channel area.

[0194] Furthermore, if the uneven shape (front convex portion, front groove portion) of the front channel uneven portion 22U extends in the front-to-back direction (when the uneven shape of the front channel uneven portion 22U in Figure 22(C) is rotated 90° with respect to the center of gravity C and arranged accordingly), the left side of the axis CY may be set to be sparse and the right side to be dense. Conversely, the left side of the axis CY may be set to be dense and the right side to be sparse. In this case, overlapping can be suppressed by stacking multiple bipolar plates 2 alternately, with each plate inverted vertically with respect to the Y side 20Y (or axis CY). The same applies to the back channel area.

[0195] As shown in Figure 22(D), the front-side inclined portion does not necessarily have to be placed in the front-side flow channel area 21U. The arrangement of the front-side flow channel irregularities 22U may be set asymmetrically front to back with the axis CX in between. In this case, the overlapping can be suppressed by stacking multiple bipolar plates 2 alternately, with the X side 20X (or axis CX) as the reference point, inverted vertically. The same applies to the back-side flow channel area.

[0196] Furthermore, if the uneven shape (front convex portion, front groove portion) of the front channel uneven portion 22U extends in the front-to-back direction (for example, if the uneven shape of the front channel uneven portion 22U in Figure 22(D) is rotated 90° with respect to the center of gravity C), the arrangement of the front channel uneven portion 22U may be set asymmetrically on either side of the axis CY. In this case, overlapping can be suppressed by stacking multiple bipolar plates 2 alternately, with each plate inverted vertically with respect to the Y side 20Y (or axis CY). The same applies to the back channel area.

[0197] As shown in Figures 22(C) to 22(D), there are no particular limitations on the presence or absence of inclined portions (front inclined portion 23U, back inclined portion) or the reference axis when inverting the bipolar plate 2 vertically. As shown in Figures 1 to 2, in the state of the laminate 91, it is sufficient that the back surface shape of the bipolar plate body 20 of the front bipolar plate 2U and the front surface shape of the bipolar plate body 20 of the back bipolar plate 2D have asymmetric shapes with respect to the reference water electrolysis member 6M in between.

[0198] The cross-sectional shape of the uneven parts (front channel uneven part 22U, back channel uneven part 22D, front gasket uneven part 26U, back gasket uneven part 26D, front connecting part 51U, back connecting part 51D, etc.) is not particularly limited. It may be a rectangular wave shape as shown in Figure 12, a triangular wave shape as shown in Figure 16(A), a wavy line shape (sine wave), etc. It is sufficient that a difference in height in the front-back direction is ensured between the top surface of the convex part and the bottom surface of the groove part of the uneven part.

[0199] The configuration of a double-sided gasketed bipolar plate manufactured by the method for manufacturing a double-sided gasketed bipolar plate according to the present disclosure is not particularly limited to the configuration of the bipolar plate 2 in the above embodiment. The front gasket 5U may be provided with a front first sealing portion 52U and a front second sealing portion 53U. The back gasket 5D may be provided with a back first sealing portion 52D and a back second sealing portion 53D.

[0200] The type of fastening member used to fasten the laminate 91 is not particularly limited. The fastening member may be a tie rod 92, a bolt, a clamp, etc. Alternatively, the fastening member may be a case that houses the laminate 91 in a compressed state in the lamination direction. The shape, position, size, and number of connecting parts (front connecting part 51U, back connecting part 51D) (hereinafter abbreviated as "shape, etc.") are not particularly limited. The same applies to the shape, etc. of the flow path area (front flow path area 21U, back flow path area 21D), seal parts (front first seal part 52U, front second seal part 53U, back first seal part 52D, back second seal part 53D), manifold (first manifold 20La, 20Rb, second manifold 20Lb, 20Ra), and through holes (front through hole 54U, back through hole 54D, through hole 200).

[0201] The electrolyte membrane 600 may be either an anion exchange membrane or a proton exchange membrane. Furthermore, the carrier for the electrode reaction may be either hydroxide ions or hydrogen ions. When the carrier is hydrogen ions, hydrogen ions can be conducted via the electrolyte membrane 600 from the front channel area 21U of the back bipolar plate 2D to the back channel area 21D of the front bipolar plate 2U.

[0202] The number and arrangement of manifolds for injecting raw material E in the raw material injection process of the insert molding process are not particularly limited. For example, a single manifold may be used for injecting raw material E. Alternatively, multiple manifolds may be used for injecting raw material E. Furthermore, manifolds may not be used for injecting raw material E at all. Also, through holes 200 may be used for injecting raw material E.

[0203] The use of adhesive in the insert molding process is not particularly limited. Using adhesive can increase the bonding strength between the front gasket 5U, the bipolar plate body 20, and the back gasket 5D.

[0204] In the press forming process, the timing of opening the manifolds shown in Figure 19(C) (first manifold 20La, 20Rb, second manifold 20Lb, 20Ra) is not particularly limited. The manifolds may be opened before or during the sheet deformation process shown in Figures 19(A) to 19(B). The same applies to the timing of opening the through holes 200.

[0205] In the press forming process, the timing of cutting out the bipolar plate body 20 shown in Figure 19(D) is not particularly limited. The bipolar plate body 20 may be cut out from the sheet material W before or during the sheet deformation process shown in Figures 19(A) to 19(B). The workpiece in the sheet deformation process may be either the sheet material (intermediate product of the bipolar plate body 20) W or the bipolar plate body 20. In the manufacturing method of the water electrolysis device 9, a non-reversal lamination process may be performed instead of the inversion lamination process. That is, multiple bipolar plates 2 may be laminated without inverting them relative to each other.

[0206] The stacking direction (front-to-back direction) of each component of the laminate 91 shown in Figure 1 is not particularly limited. The stacking direction may be vertical, horizontal, or a direction intersecting both the vertical and horizontal directions. Thus, the stacking direction, front-to-back direction (front side, back side), X direction, Y direction, XY plane, inclination direction, etc., in this disclosure are not particularly limited. The shapes of the bipolar plate 2 and the water electrolysis member 6 are not particularly limited. When viewed from the front-to-back direction, they may be rectangular, square, rhombus, circular, elliptical, etc. The types of the first fluid L1 and the second fluid L2 are not particularly limited.

[0207] The material of the bipolar plate body 20 is not particularly limited. Preferably, it is a metal that is conductive and non-corrosive. Examples include stainless steel, titanium, copper, magnesium, and aluminum.

[0208] The material of gasket 5 is not particularly limited. Any elastomer with insulating and rubber elasticity is acceptable. It is sufficient that it has fluidity at the raw material E stage. In addition to the rubber component, gasket 5 may also contain crosslinking agents, co-crosslinking agents, processing aids, softeners, reinforcing materials, etc. Suitable rubber components include VMQ (silicone rubber), as well as other silicone rubbers (such as PVMQ (phenyl vinyl methyl silicone rubber) and FVMQ (fluoro vinyl methyl silicone rubber)), EPDM (ethylene propylene diene rubber), and FKM (fluororubber). When liquid silicone rubber is used as raw material E, the type of liquid silicone rubber is not particularly limited. It may be a one-component type or a two-component type. It may also be a room-temperature curing type or a heat-curing type.

[0209] 2: Bipolar plate with double-sided gaskets, 2U: Front bipolar plate, 2D: Back bipolar plate 20: Bipolar plate body, 20La: First manifold, 20Lb: Second manifold, 20Ra: Second manifold, 20Rb: First manifold, 20X: X side, 20Y: Y side, 20f: Flange section, 20U: Top surface (front), 20D: Bottom surface (back) 21U: Front flow path area, 21D: Back flow path area, 22U: Front flow path uneven section, 22D: Back flow path uneven section, 220U: Front convex section, 220D: Back convex section, 221U: Front groove section, 221D: Back groove section, 23U: Front inclined section, 23D: Back inclined section 25U: Front side placement part, 25D: Back side placement part, 26U: Front side gasket uneven part, 26D: Back side gasket uneven part, 260U: Front side convex part, 260D: Back side convex part, 261U: Front side groove part, 261D: Back side groove part 200: Through hole, 202: Rod insertion hole 5: Gasket, 5c: Cavity, 5U: Front side gasket, 5Uc: Front side molded part, 5D: Back side gasket, 5Dc: Back side molded part 5Ma: Connecting part, 5Mac: Connecting part molded part, 5Mb: Covering part, 5Mbc: Covering part molded part 50U: Front side base layer, 50Uc: Front side base layer molded part, 50D: Back side base layer molded part 51U: Front connecting part, 51D: Back connecting part, 510U: Front protrusion, 510D: Back protrusion, 511U: Front groove, 511D: Back groove 52U: Front first seal part, 52Uc: Front first molded part, 52D: Back first seal part, 52Dc: Back first molded part, 53U: Front second seal part, 53D: Back second seal part, 53Dc: Back second molded part, 54U: Front through hole, 54D: Back through hole 6: Water electrolysis member, 6M: Standard water electrolysis member, 60: Electrolysis part, 600: Electrolyte membrane, 601U: Front catalyst layer, 601D: Back catalyst layer, 602U: Front diffusion layer, 602D: Back diffusion layer, 61: Frame part 7: Press molding die, 7U: Upper die, 7D: Lower die, 70U: Front molding section, 70D: Back molding section 8: Insert molding die, 8U: Upper die, 8D: Lower die, 800U: Front pin, 800D: Back pin 9: Water electrolysis device, 90: End plate, 91: Laminate, 92: Tie rod (fastening member) C: Center of gravity, CX: Axis, CY: Axis, E: Raw material, F: Fastening force, G: Gate, L1: First fluid, L2: Second fluid, O: Gasket overlap section, S: Scrap, Sc: Scrap generation section, W: Plate material (intermediate product)

Claims

1. A double-sided gasketed double-sided gasketed double-sided gasket for a water electrolysis apparatus, comprising: a press-formed metal plate having a first manifold through which a first fluid on the anode side flows and a second manifold through which a second fluid on the cathode side flows, with a front flow path area and a front arrangement portion disposed on the surface and a back flow path area and a back arrangement portion disposed on the back surface; and a gasket having an elastomer front gasket disposed on the front arrangement portion and an elastomer back gasket disposed on the back arrangement portion, wherein the front gasket has a front first seal portion surrounding the first manifold and the front flow path area and a front second seal portion surrounding the second manifold, and the back gasket has a back first seal portion surrounding the first manifold and a back second seal portion surrounding the second manifold and the back flow path area.

2. The front gasket has a front base layer laminated on the front arrangement portion and having a front through hole penetrating it in the front-back direction, and a front connecting portion formed on the front base layer and connecting the first manifold and the front flow path area; the back gasket has a back base layer laminated on the back arrangement portion and having a back through hole penetrating it in the front-back direction, and a back connecting portion formed on the back base layer and connecting the second manifold and the back flow path area; the water electrolysis apparatus comprises a laminate in which the double-sided gasketed bipolar plates and water electrolysis members are alternately laminated in the front-back direction, wherein any of the water electrolysis members is designated as a reference water electrolysis member, the double-sided gasketed bipolar plate laminated adjacent to the front side of the reference water electrolysis member is designated as a front bipolar plate, and the double-sided gasketed bipolar plate laminated adjacent to the back side of the reference water electrolysis member is designated as a back bipolar plate; The double-sided gasketed bipolar plate according to claim 1, wherein the rear connecting portion of the front bipolar plate and the front connecting portion of the rear bipolar plate are elastically in contact with the reference water electrolysis member.

3. The front-side arrangement portion has a front-side gasket uneven portion having undulations in the front-back direction, the back-side arrangement portion has a back-side gasket uneven portion having undulations in the front-back direction, and the front-side gasket uneven portion and the back-side gasket uneven portion are arranged opposite each other in the front-back direction and exhibit a shape that is symmetrical with respect to each other, as described in claim 1.

4. The bipolar plate body has a through hole that penetrates it in the front-to-back direction, and when viewed from the front-to-back direction, the front-side first seal portion, the front-side second seal portion, the back-side first seal portion, and the back-side second seal portion each have an annular shape, and when viewed from the front-to-back direction, the through hole is located on the outer side of the annular shape of the front-side first seal portion, the front-side second seal portion, the back-side first seal portion, and the back-side second seal portion, and the gasket has an elastomer connecting portion that connects the front-side gasket and the back-side gasket in the front-to-back direction and is located inside the through hole, and the front-side gasket, the back-side gasket and the connecting portion are integrally connected, as described in claim 1.

5. The double-sided gasketed bipolar plate according to claim 4, wherein the gasket connects the front gasket and the back gasket in the front-back direction and has a covering portion that covers the inner circumferential surface of the first manifold and the inner circumferential surface of the second manifold, and the front gasket, the back gasket and the covering portion are integrally connected.

6. The front channel area has a front channel uneven portion having undulations in the front-back direction, the back channel area has a back channel uneven portion having undulations in the front-back direction, and the front channel uneven portion and the back channel uneven portion are arranged opposite each other in the front-back direction and exhibit a shape that is symmetrical to each other, as described in claim 1.

7. The water electrolysis apparatus comprises a laminate in which the double-sided gasketed bipolar plates and water electrolysis members are alternately stacked in the front-back direction, wherein any water electrolysis member is designated as a reference water electrolysis member, the double-sided gasketed bipolar plate stacked adjacent to the front side of the reference water electrolysis member is designated as a front-side bipolar plate, and the double-sided gasketed bipolar plate stacked adjacent to the back side of the reference water electrolysis member is designated as a back-side bipolar plate, wherein any pair of directions that intersect each other is designated as the X direction and the Y direction, the plane containing the X direction and the Y direction is designated as the XY plane, and the direction that intersects the X direction and the Y direction within the XY plane is designated as the inclination direction, wherein the bipolar plate body has a quadrilateral shape having a pair of X sides extending in the X direction and a pair of Y sides extending in the Y direction, the front-side flow channel irregularities have a front-side inclined portion extending in the inclination direction, and the back-side flow channel irregularities have a back-side inclined portion extending in the same direction as the front-side inclined portion. The front-side inclined portion and the back-side inclined portion are arranged opposite each other in the front-back direction and have a shape that is symmetrical to each other, and in the laminate, the front-side bipolar plate and the back-side bipolar plate are laminated in a reversed manner in the front-back direction with respect to the X side or the Y side, as described in claim 6.

8. A water electrolysis apparatus comprising a laminate in which a double-sided gasketed bipolar plate and a water electrolysis member having an electrolyte membrane are alternately stacked in the front-back direction, as described in claim 1.

9. In the bipolar plate body, the front channel area has a front channel uneven portion having undulations in the front-back direction, and the back channel area has a back channel uneven portion having undulations in the front-back direction, and the front channel uneven portion and the back channel uneven portion are arranged opposite each other in the front-back direction and exhibit a symmetrical shape with respect to each other, and in the laminate, any water electrolysis member is called a reference water electrolysis member, the bipolar plate with double gaskets laminated adjacent to the front side of the reference water electrolysis member is called a front bipolar plate, and the bipolar plate with double gaskets laminated adjacent to the back side of the reference water electrolysis member is called a back bipolar plate, and any pair of directions that intersect each other is called the X direction and the Y direction, the plane including the X direction and the Y direction is called the XY plane, and the direction that intersects the X direction and the Y direction within the XY plane is called the inclination direction, and the bipolar plate body has a quadrilateral shape having a pair of X sides extending in the X direction and a pair of Y sides extending in the Y direction, The water electrolysis apparatus according to claim 8, wherein the front channel irregularities have a front inclined portion extending in the inclined direction, the back channel irregularities have a back inclined portion extending in the same direction as the front inclined portion, the front inclined portion and the back inclined portion are arranged opposite each other in the front-back direction and exhibit a shape that is symmetrical to each other, and in the laminate, the front bipolar plate and the back bipolar plate are laminated inverted in the front-back direction with respect to the X side or the Y side.

10. The water electrolysis apparatus according to claim 8, wherein the water electrolysis member comprises an electrolytic section having the electrolyte membrane and a frame section surrounding the electrolytic section and having a higher rigidity than the electrolyte membrane.

11. A method for manufacturing a double-sided gasketed bipolar plate according to claim 1, comprising: a press molding step of manufacturing the bipolar plate body by press molding; and an insert molding step of molding the gasket in a cavity in which the bipolar plate body is arranged and joining the gasket to the bipolar plate body, wherein the insert molding step comprises: an arrangement step of arranging the bipolar plate body in a mold of an insert molding die that partitions the cavity; a raw material injection step of injecting raw material into the cavity of the insert molding die; and a curing step of curing the raw material injected into the cavity to integrally form the gasket and joining the gasket to the bipolar plate body.

12. The method for manufacturing a bipolar plate with a double-sided gasket according to claim 11, wherein in the raw material injection step, the raw material is injected into the cavity of the insert molding die from at least one of the first manifold and the second manifold.

13. The front-side arrangement portion has a front-side gasket uneven portion having undulations in the front-back direction, the back-side arrangement portion has a back-side gasket uneven portion having undulations in the front-back direction, the front-side gasket uneven portion and the back-side gasket uneven portion are arranged opposite each other in the front-back direction and exhibit a symmetrical shape, the press forming die used in the press forming process has a front-side forming portion for forming the front-side gasket uneven portion and a back-side forming portion for forming the back-side gasket uneven portion, the front-side forming portion and the back-side forming portion are arranged opposite each other in the opening and closing direction of the press forming die and exhibit a symmetrical shape, A method for manufacturing a double-sided gasketed bipolar plate according to claim 11, wherein in the press forming step, the bipolar plate body or an intermediate product of the bipolar plate body is sandwiched between the front forming portion and the back forming portion, thereby forming the front gasket uneven portion on the front placement portion and the back gasket uneven portion on the back placement portion.

14. The method for manufacturing a bipolar plate with double-sided gaskets according to claim 11, wherein the bipolar plate body has a through hole that penetrates it in the front-to-back direction, the front-side first seal portion, the front-side second seal portion, the back-side first seal portion, and the back-side second seal portion are each annular when viewed from the front-to-back direction, the through hole is located on the outer side of the annular portion of the front-side first seal portion, the front-side second seal portion, the back-side first seal portion, and the back-side second seal portion when viewed from the front-to-back direction, the gasket is located inside the through hole and has an elastomer connecting portion that connects the front-side gasket and the back-side gasket in the front-to-back direction, the front-side gasket, the back-side gasket, and the connecting portion are integrally connected, and in the raw material injection step, the raw material is flowed through the through hole in the front-to-back direction of the bipolar plate body, and in the curing step, the raw material in the through hole is cured to form the connecting portion together with the front-side gasket and the back-side gasket.

15. The method for manufacturing a bipolar plate with double-sided gaskets according to claim 11, wherein the front gasket has a front base layer made of elastomer laminated on the front placement portion, the front first seal portion and the front second seal portion are laminated on the surface of the front base layer, the back gasket has a back base layer made of elastomer laminated on the back placement portion, the back first seal portion and the back second seal portion are laminated on the back surface of the back base layer, and the cavity of the insert molding die has a front base layer molding portion for molding the front base layer and a back base layer molding portion for molding the back base layer.

16. A method for manufacturing a water electrolysis apparatus comprising a laminate in which a double-sided gasketed bipolar plate and a water electrolysis member having an electrolyte membrane are alternately stacked in the front-back direction, the method comprising: a stacking step of alternately stacking the double-sided gasketed bipolar plate and the water electrolysis member in the front-back direction to produce the laminate; and a fastening step of placing end plates on both ends of the laminate in the stacking direction and applying a fastening force to the laminate from the stacking direction to press-fit adjacent double-sided gasketed bipolar plates and water electrolysis members in the stacking direction.

17. In the laminate, any water electrolytic member is designated as a reference water electrolytic member, the double-sided gasketed bipolar plate laminated adjacent to the front side of the reference water electrolytic member is designated as the front bipolar plate, and the double-sided gasketed bipolar plate laminated adjacent to the back side of the reference water electrolytic member is designated as the back bipolar plate, and any pair of intersecting directions is designated as the X direction and the Y direction, the plane containing the X direction and the Y direction is designated as the XY plane, and the directions intersecting the X direction and the Y direction within the XY plane are designated as the inclination direction, the bipolar plate body has a quadrilateral shape having a pair of X sides extending in the X direction and a pair of Y sides extending in the Y direction, the front channel irregularities have a front inclined portion extending in the inclination direction, the back channel irregularities have a back inclined portion extending in the same direction as the front inclined portion, the front inclined portion and the back inclined portion are arranged opposite each other in the front-back direction and have a shape that is symmetrical to each other, The method for manufacturing a water electrolysis apparatus according to claim 16, wherein the lamination step is a reverse lamination step in which the front bipolar plate and the back bipolar plate are laminated in the front-to-back direction with respect to the X side or the Y side, so that when viewed from the front-to-back direction, the back-side inclined portion of the front bipolar plate and the front-side inclined portion of the back bipolar plate extend in different directions from each other.

Images