Bipolar plate with double-sided gaskets, water electrolysis device provided with said bipolar plate with double-sided gaskets, and method for manufacturing said water electrolysis device
Patent Information
- Application Number
- PCT/JP2026/004691
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2025-02-18
- Filing Date
- 2026-02-09
- Publication Date
- 2026-08-27
Smart Images
Figure JP2026004691_27082026_PF_FP_ABST
Abstract
Description
Bipolar plate with double-sided gaskets, water electrolysis device including the bipolar plate with double-sided gaskets, and method for manufacturing the water electrolysis device
[0001] The present disclosure relates to a bipolar plate with double-sided gaskets, a water electrolysis device including the bipolar plate with double-sided gaskets, and a method for manufacturing the water electrolysis device.
[0002] A water electrolysis device electrolyzes water to produce hydrogen and oxygen. The water electrolysis device of Patent Document 1 includes a laminate of a plurality of separators and a plurality of electrolytic cells.
[0003] International Publication No. 2024 / 106305 pamphlet
[0004] When a conductive fluid is supplied in parallel from a common supply source to each electrolytic cell, a self-discharge current flows through the conductive fluid in the flow path according to the potential difference of each electrolytic cell. This self-discharge current is called a shunt current. When the shunt current flows, the Faraday efficiency decreases. The Faraday efficiency is the ratio of the amount of charge contributed to the production of hydrogen when the total amount of charge input to the electrolytic cell is set to 100%. The larger the shunt current, the lower the Faraday efficiency.
[0005] Therefore, an object of the present disclosure is to provide a bipolar plate with double-sided gaskets capable of reducing the shunt current, a water electrolysis device including the bipolar plate with double-sided gaskets, and a method for manufacturing the water electrolysis device.
[0006] (1) To solve the above problems, the double-sided gasketed bipolar plate of the present disclosure comprises a metal bipolar plate body 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, a front flow path area through which the first fluid flows and a front arrangement portion disposed on the surface, and a back flow path area through which the second fluid flows 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 comprises a front base layer laminated on the front arrangement portion, a front first seal portion protruding from the front base layer to the front side and surrounding the first manifold and the front flow path area, a front second seal portion protruding from the front base layer to the front side and surrounding the second manifold, and disposed on the front base layer and the first manifold and the front The gasket has a front connecting portion that connects to the flow path area, and when viewed from the front-back direction, the front base layer is located on the ring side of the front first seal portion and the front second seal portion, and is arranged over the entire surface of the portion excluding the first manifold, the second manifold, and the front flow path area. The back gasket has a back base layer laminated in the back arrangement portion, a back first seal portion that protrudes to the back from the back base layer and surrounds the first manifold, a back second seal portion that protrudes to the back from the back base layer and surrounds the second manifold and the back flow path area, and a back connecting portion arranged in the back base layer that connects the second manifold and the back flow path area. When viewed from the front-back direction, the back base layer is located on the ring side of the back first seal portion and the back second seal portion, and is arranged over the entire surface of the portion excluding the first manifold, the second manifold, and the back flow path area. Here, the "with" in "double-sided gasketed bipolar plate" means that the bipolar plate body and the gasket are integrated into a single unit.
[0007] Hereafter, when viewing the bipolar plate body from the front side, the first manifold (the area to be sealed by the first seal on the front side), the second manifold (the area to be sealed by the second seal on the front side), and the front flow path area (the area to be sealed by the first seal on the front side) will be referred to as the "front side sealed area." Similarly, when viewing the bipolar plate body from the back side, the first manifold (the area to be sealed by the first seal on the back side), the second manifold (the area to be sealed by the second seal on the back side), and the back flow path area (the area to be sealed by the second seal on the back side) will be referred to as the "back side sealed area."
[0008] In this configuration, the front base layer of the front gasket is located on the inner side of the first front seal portion and the second front seal portion, and is distributed over the entire surface excluding the portion to be sealed on the front side. Therefore, shunt current can be reduced. Similarly, the back base layer of the back gasket is located on the inner side of the first back seal portion and the second back seal portion, and is distributed over the entire surface excluding the portion to be sealed on the back side. Therefore, shunt current can be reduced.
[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] (2) In the configuration of (1) above, the front-side arrangement portion may have a plurality of plate-side grooves covered by the front-side base layer, and the back-side arrangement portion may have a plurality of plate-side grooves covered by the back-side base layer.
[0011] The groove on the front side of the plate is covered by the front base layer. This suppresses misalignment of the front gasket relative to the surface of the bipolar plate body. Similarly, the groove on the back side of the plate is covered by the back base layer. This suppresses misalignment of the back gasket relative to the back surface of the bipolar plate body. Furthermore, by suppressing misalignment, it is possible to maintain the state in which the parts of the bipolar plate body where improved electrical insulation is desired are covered by the front gasket and back gasket. This reduces shunt current.
[0012] (2-1) In the configuration of (2) above, the groove on the front side of the plate may have, when viewed from the front-back direction, a first groove on the front side that overlaps with the first seal on the front side and a second groove on the front side that overlaps with the second seal on the front side, and the groove on the back side of the plate may have, when viewed from the front-back direction, a first groove on the back side that overlaps with the first seal on the back side and a second groove on the back side that overlaps with the second seal on the back side.
[0013] The first groove on the front side extends along the first sealing portion on the front side. Similarly, the second groove on the front side extends along the second sealing portion on the front side. In other words, the first and second grooves on the front side surround the aforementioned sealing portion on the front side. Therefore, misalignment of the first and second sealing portions on the front side relative to the surface of the bipolar plate body can be suppressed. Consequently, the sealing portion on the front side can be reliably sealed.
[0014] Similarly, the first groove on the back extends along the first sealing portion on the back. The second groove on the back extends along the second sealing portion on the back. That is, the first and second grooves on the back surround the aforementioned sealing portion on the back. Therefore, misalignment of the first and second sealing portions on the back relative to the back surface of the bipolar plate body can be suppressed. Consequently, the sealing portion on the back can be reliably sealed.
[0015] (3) In the configuration of (2) or (2-1) above, the plate front side groove portion has a front side connecting groove portion, the plate back side groove portion has a back side connecting groove portion, the front side connecting portion has a plurality of front side protrusions arranged on the front side of the front side connecting groove portion and a front side groove portion partitioned between a pair of adjacent front side protrusions through which the first fluid flows, and the back side connecting portion has a plurality of back side protrusions arranged on the back side of the back side connecting groove portion and a back side groove portion partitioned between a pair of adjacent back side protrusions through which the second fluid flows.
[0016] The front-side protrusion and the front-side connecting groove overlap in the front-to-back direction. Therefore, the elastic deformation range of the front-side protrusion in the front-to-back direction can be increased. Consequently, the elastic contact force with the adjacent front-side member (e.g., water electrolysis member, end plate, etc.) can be increased. Thus, leakage of the first fluid from the front-side groove can be suppressed. Similarly, since the back-side protrusion and the back-side connecting groove overlap in the front-to-back direction, leakage of the second fluid from the back-side groove can be suppressed. In addition, the front-side connecting groove can suppress misalignment of the front-side connecting portion relative to the front-side arrangement portion. Similarly, the back-side connecting groove can suppress misalignment of the back-side connecting portion relative to the back-side arrangement portion.
[0017] (4) In any of the above configurations, the front-side arrangement portion has a front-side base portion with an uneven shape that overlaps the front-side connecting portion when viewed from the front-back direction, the front-side base layer has an uneven shape that follows the uneven shape of the front-side base portion, the front-side connecting portion has a front-side convex portion and a front-side groove portion partitioned between an adjacent pair of front-side convex portions through which the first fluid flows, and the front-side convex portion and the front-side groove portion are arranged using the uneven shape of the front-side base layer The back-side arrangement portion has a back-side base portion with an uneven shape that overlaps the back-side connecting portion when viewed from the front-back direction, the back-side base layer has an uneven shape that follows the uneven shape of the back-side base portion, the back-side connecting portion has a back-side convex portion and a back-side groove portion partitioned between a pair of adjacent back-side convex portions through which the second fluid flows, and the back-side convex portion and the back-side groove portion may be arranged using the uneven shape of the back-side base layer.
[0018] The front-side configuration portion has a front-side base portion with an uneven surface. The front-side base layer covers the front-side base portion from the front. The uneven surface of the front-side base layer is transferred to the surface of the front-side base layer due to the uneven surface of the front-side base portion. With this configuration, by simply laminating the front-side base layer onto the front-side base portion, the uneven surface of the front-side base portion can be used to position the front-side convex portion and the front-side groove portion on the front-side connecting portion. Similarly, with this configuration, the uneven surface of the back-side base portion can be used to position the back-side convex portion and the back-side groove portion on the back-side connecting portion. Furthermore, the front-side base portion can suppress misalignment of the front-side connecting portion relative to the front-side configuration portion. Similarly, the back-side base portion can suppress misalignment of the back-side connecting portion relative to the back-side configuration portion.
[0019] (5) In any of the above configurations, 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.
[0020] In this configuration, the inner surfaces of both the first and second manifolds, which are made of metal, are covered with an elastomer coating. This protects the inner surfaces of both the first and second manifolds and reduces shunt current.
[0021] Furthermore, the front gasket and the back gasket are integrated via the covering portion. Therefore, the back gasket can prevent the front gasket from peeling off the surface of the bipolar plate body. Similarly, the front gasket can prevent the back gasket from peeling off the back surface of the bipolar plate body. Thus, the bipolar plate body and the gaskets can be integrated.
[0022] (6) In any of the above configurations, the bipolar plate body may have a spacer that protrudes in the front-back direction, and when viewed from the front-back direction, the spacer may be arranged on the outer side of the rings 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. This configuration makes it possible to increase the shape stability of the bipolar plate with double-sided gaskets.
[0023] (7) 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.
[0024] (7-1) In the configuration of (7) above, the electrolyte membrane may be an anion exchange membrane or a proton exchange membrane. In the laminate, any water electrolytic member is designated 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 designated as the front bipolar plate, and a double-sided gasketed bipolar plate laminated adjacent to the back side of the reference water electrolytic member is designated as the back bipolar plate.
[0025] 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.
[0026] (8) In the configuration of (7) or (7-1) 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 increase the shape stability of the electrolyte membrane in the electrolytic section.
[0027] (9) In any of the configurations described in (7) to (8) above, in the laminate, any water electrolytic member may be 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 may be 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 may be designated as a back bipolar plate, and the back gasket of the front bipolar plate and the front gasket of the back bipolar plate may be configured to include at least one of the following configurations: (Configuration A) When viewed from the lamination direction, at least a part of the back connecting portion of the front bipolar plate and at least a part of the front gasket of the back bipolar plate overlap with each other. (Configuration B) When viewed from the lamination direction, at least a part of the front connecting portion of the back bipolar plate and at least a part of the back gasket of the front bipolar plate overlap with each other.
[0028] 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.
[0029] 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.
[0030] (10) 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 (6) above and a water electrolysis member having an electrolyte membrane are alternately stacked in the front-back direction, characterized in that it comprises a stacking step of alternately stacking the double-sided gasketed bipolar plate and the water electrolysis member 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.
[0031] 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.
[0032] According to this disclosure, it is possible to provide a bipolar plate with double-sided gaskets capable of reducing shunt current, a water electrolysis apparatus equipped with the bipolar plate with double-sided gaskets, and a method for manufacturing the water electrolysis apparatus.
[0033] 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 top view of the double-sided gasketed bipolar plate. Figure 4 is a top view of the bipolar plate body of the double-sided gasketed bipolar plate. Figure 5 is a top view of the front gasket of the double-sided gasketed bipolar plate. Figure 6 is a bottom view of the double-sided gasketed bipolar plate. Figure 7 is a bottom view of the bipolar plate body of the double-sided gasketed bipolar plate. Figure 8 is a bottom view of the back gasket of the double-sided gasketed bipolar plate. Figure 9 is a top view of the water electrolysis member of the double-sided gasketed bipolar plate. Figure 10 is an enlarged view of the area within frame X of Figure 3. Figure 11 is an enlarged view of the area within frame X of Figure 6. Figure 12 is a cross-sectional view of Figure 10 in the direction of XII-XII. Figure 13 is a cross-sectional view of Figure 10 in the direction of XIII-XIII. Figure 14 is a top view of the double-sided gasketed bipolar plate with the front and back gaskets superimposed. Figure 15 is an enlarged view of the area within frame X in Figure 14. Figure 16 is a partial cross-sectional view in the vertical direction of a double-sided gasketed bipolar plate of another embodiment.
[0034] The following describes embodiments of the double-sided gasketed bipolar plate, a water electrolysis apparatus equipped with the double-sided gasketed bipolar plate, and a method for manufacturing the water electrolysis apparatus. First, the correspondence between the directions in the following drawings and the directions in the disclosure will be explained. In the following figures, the upper side corresponds to the "front side" of the disclosure, the lower side corresponds to the "back side" of the disclosure, and the vertical direction corresponds to the "front / back direction" and "stack direction" of the disclosure. Figure 1 shows 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 disclosure. Figure 2 shows an exploded perspective view of section II in Figure 1. 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.
[0035] <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. The plurality of water electrolyzer members 6 are electrically connected in series.
[0036] 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 plurality of tie rods (fastening members) 92. 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.
[0037] The bipolar plates 2 and the water electrolysis member 6 that constitute the laminate 91 are not adhered to each other. These members are positioned vertically and horizontally (directions perpendicular to the vertical direction, front-back and left-right directions, and along the lamination direction relative to the lamination direction) by the fastening force F described above.
[0038] 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".
[0039] <Double-sided gasketed bipolar plate 2> Next, the configuration of the bipolar plate 2 will be explained. Figure 3 shows a top view of the double-sided gasketed bipolar plate (specifically, the back side bipolar plate 2D in Figure 2).
[0040] In each figure, frame X indicates a common part (the left front portion of the double-sided gasketed bipolar plate 2). Figure 12 shows a vertical cross-sectional view of a part of the laminate 91 (section II in Figure 1). As shown in Figures 3 to 9, when viewed from the vertical direction, the linear axis extending horizontally through the centroid C of each member is called "axis CX". The linear axis extending vertically through the centroid C is called "axis CY".
[0041] As shown in FIGS. 3 to 8, the bipolar plate 2 (the back bipolar plate 2D in FIG. 2) includes a bipolar plate body 20 and a gasket 5. In the orientation of the paper surface, the front-rear direction is opposite between FIGS. 3 to 5 (top view) and FIGS. 6 to 8 (bottom view).
[0042] [Bipolar Plate Body 20] As shown in FIGS. 4 and 7, the bipolar plate body 20 is an integrally formed metal object and has a rectangular shape when viewed from the up-down direction (in plan view). The bipolar plate body 20 includes a base portion 200 and four spacers 201. The four spacers 201 are arranged along the outer edge (four sides) of the bipolar plate body 20. Among the four spacers 201, a pair of left and right spacers 201 are arranged at the central portions in the front-rear direction of the left and right edges of the bipolar plate body 20. The pair of front and rear spacers 201 are arranged over the entire length of the front and rear edges of the bipolar plate body 20. The base portion 200 corresponds to the portion of the bipolar plate body 20 other than the four spacers 201. As shown in FIG. 2, the four spacers 201 project on both the upper and lower sides with respect to the base portion 200. That is, the spacer 201 has a greater thickness in the up-down direction than the base portion 200.
[0043] (Openings in the Bipolar Plate Body 20) As shown in FIGS. 4 and 7, a plurality of openings (specifically, two first manifolds 20La, 20Rb, two second manifolds 20Lb, 20Ra) are formed in the bipolar plate body 20. These openings penetrate the bipolar plate body 20 in the up-down direction. When viewed from the up-down direction, these openings are arranged symmetrically with respect to the axis CY. Also, these openings are arranged symmetrically with respect to the axis CX.
[0044] The first manifold 20La is arranged at the left front corner of the base portion 200. The first manifold 20Rb is arranged at the right rear corner of the base portion 200 (the diagonal position of the first manifold 20La with respect to the center of gravity C). Water (conductive fluid) flows as the first fluid L1 in the first manifold 20Rb. Water containing oxygen (a product of electrolysis) flows as the first fluid L1 in the first manifold 20La.
[0045] The second manifold 20Lb is disposed at the left rear corner of the base 200. The second manifold 20Ra is disposed at the right front corner of the base 200 (diagonal position of 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. Note that the second manifold 20Ra is sealed.
[0046] Thus, the water electrolysis device 9 produces oxygen (the first fluid L1 in the first manifold 20La) and hydrogen (the second fluid L2 in the second manifold 20Lb) from water (the first fluid L1 in the first manifold 20Rb) by electrolysis.
[0047] (Configuration on the upper surface 20U side of the base 200 of the bipolar plate body 20) As shown in FIG. 4, a front-side flow path area 21U and a front-side arrangement portion 25U are disposed on the upper surface (front surface) 20U of the base 200 of the bipolar plate body 20. As shown by the dotted frames in FIGS. 3 to 5, the front-side flow path area 21U has a rectangular shape when viewed from the vertical direction. The front-side flow path area 21U is disposed inside the first manifolds 20La and 20Rb and the second manifolds 20Lb and 2 / Ra in the left-right direction. The front-side flow path area 21U has a concavo-convex shape (not shown) with undulations in the vertical direction. The first fluid L1 flows through the front-side flow path area 21U.
[0048] As shown in FIGS. 3 to 4, the front-side arrangement portion 25U includes a front-side first arrangement portion 25Ua and two front-side second arrangement portions 25Ub. The front-side first arrangement portion 25Ua comprehensively surrounds the first manifolds 20La and 20Rb and the front-side flow path area 21U. The two front-side second arrangement portions 25Ub individually surround the second manifolds 20Lb and 20Ra.
[0049] A front-side groove portion 27U is recessed in the front-side arrangement portion 25U. The front-side groove portion 27U includes a front-side first groove portion 27Ua, two front-side second groove portions 27Ub, and a plurality of front-side connecting groove portions 27Uc. Among these, the front-side first groove portion 27Ua and the plurality of front-side connecting groove portions 27Uc are disposed in the front-side first arrangement portion 25Ua. The two front-side second groove portions 27Ub are disposed in the front-side second arrangement portions 25Ub, respectively.
[0050] The first groove 27Ua on the front side extends so as to overlap with the first seal portion 52U on the front side, which will be described later, when viewed from the vertical direction. The first groove 27Ua on the front side comprehensively surrounds the first manifolds 20La, 20Rb and the front flow path area 21U. The second groove 27Ub on the front side extends so as to overlap with the second seal portion 53U on the front side, which will be described later, when viewed from the vertical direction. The two second grooves 27Ub on the front side individually surround the second manifolds 20Lb, 21Ra.
[0051] The multiple front-side connecting grooves 27Uc extend so as to overlap with the front-side connecting portion 51U (specifically, the multiple front-side protrusions 510U) described later, when viewed from the top and bottom. The multiple front-side connecting grooves 27Uc are arranged in the front-to-back direction. The front-side connecting grooves 27Uc extend in the left-to-right direction.
[0052] (Configuration of the lower surface 20D side of the base 200 of the bipolar plate body 20) The configuration (shape, arrangement, etc.) of the lower surface (back surface) 20D side of the base 200 of the bipolar plate body 20 corresponds to "the configuration of the upper surface 20U side described above, inverted (rotated 180°) in the vertical direction with respect to axis CX or axis CY." The configuration of the lower surface 20D side will be briefly described below.
[0053] As shown in Figure 7, a back-side flow path area 21D and a back-side arrangement area 25D are arranged on the lower surface 20D of the base 200 of the bipolar plate body 20. As shown by the dotted lines in Figures 6 to 8, the back-side flow path area 21D has a rectangular shape when viewed from above. The front-side flow path area 21U and the back-side flow path area 21D are opposite each other in the vertical direction. The back-side flow path area 21D has an uneven shape with undulations in the vertical direction (not shown). The second fluid L2 flows through the back-side flow path area 21D.
[0054] As shown in Figures 6 and 7, the rear side configuration section 25D comprises two rear side first configuration sections 25Da and a rear side second configuration section 25Db. The two rear side first configuration sections 25Da individually surround the first manifolds 20La and 20Rb. The rear side second configuration section 25Db comprehensively surrounds the second manifolds 20Lb and 20Ra and the rear side flow path area 21D.
[0055] A groove portion 27D is recessed in the back side arrangement portion 25D. The groove portion 27D on the back side comprises two back side first groove portions 27Da, a back side second groove portion 27Db, and a plurality of back side connecting groove portions 27Dc. Of these, the two back side first groove portions 27Da are each located in the back side first arrangement portion 25Da. The back side second groove portion 27Db and the plurality of back side connecting groove portions 27Dc are located in the back side second arrangement portion 25Db.
[0056] The first groove 27Da on the back side extends so as to overlap with the first seal portion 52D on the back side, which will be described later, when viewed from the vertical direction. The two first grooves 27Da on the back side individually surround the first manifolds 20La and 20Rb. The second groove 27Db on the back side extends so as to overlap with the second seal portion 53D on the back side, which will be described later, when viewed from the vertical direction. The two second grooves 27Db on the back side comprehensively surround the second manifolds 20Lb and 21Ra and the back flow path area 21D.
[0057] The rear connecting groove 27Dc extends so as to overlap with the rear connecting portion 51D (specifically, the multiple rear protrusions 510D) described later, when viewed from above. The multiple rear connecting grooves 27Dc are arranged in the front-to-back direction. The rear connecting grooves 27Dc extend in the left-to-right direction.
[0058] [Gasket 5] Gasket 5 is made of elastomer (for example, EPDM (ethylene propylene diene rubber)). As shown in Figures 2-3, 5-6, 8, and 10-15, gasket 5 comprises a front gasket 5U, a back gasket 5D, and four covering portions 5Mb.
[0059] (Front gasket 5U) As shown in Figures 3 to 5 and 12 to 13, the front gasket 5U is positioned 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.
[0060] The front base layer 50U is laminated on the front arrangement section 25U. More specifically, the front base layer 50U comprises a front first base layer 50Ua and two front second base layers 50Ub. The front first base layer 50Ua is laminated on the front first arrangement section 25Ua. The two front second base layers 50Ub are each laminated on the front second arrangement section 25Ub.
[0061] The front-side first seal portion 52U is laminated on the upper surface of the front-side first base layer 50Ua. The front-side first seal portion 52U is located above the front-side first groove portion 27Ua. The front-side first seal portion 52U extends along the outer edge of the front-side first base layer 50Ua. The front-side first seal portion 52U comprehensively surrounds the first manifolds 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 Figure 12, 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).
[0062] The two front-side second seal portions 53U are each laminated on the upper surface of the front-side second base layer 50Ub. The two front-side second seal portions 53U are each positioned above the front-side second groove portion 27Ub. The two front-side second seal portions 53U each extend along the outer edge of the front-side second base layer 50Ub. 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 exhibit 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.
[0063] The two front-side connecting portions 51U are formed in the front-side first base layer 50Ua. 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.
[0064] Specifically, as shown in Figures 10, 12-13, the front connecting portion 51U comprises a plurality of front protrusions 510U and a plurality of front grooves 511U. Each of the plurality of front protrusions 510U is positioned above the front connecting groove 27Uc. The plurality of front protrusions 510U are arranged in the front-to-back direction. The front protrusions 510U extend in the left-to-right direction. The front grooves 511U are flush with the front first base layer 50Ua. The front grooves 511U are partitioned between adjacent pairs of front protrusions 510U. The plurality of front grooves 511U are arranged in the front-to-back direction. The front grooves 511U extend in the left-to-right direction. The first fluid L1 flows through the front grooves 511U.
[0065] As shown in Figure 13, the front projection 510U protrudes upward relative to the front groove 511U. As shown in Figure 12, the front projection 510U is elastically in contact with the reference water electrolysis member 6M.
[0066] (Backside gasket 5D) As shown in Figures 5 and 8 (the front and rear directions of Figures 5 and 8 are opposite to each other in terms of the orientation of the paper), the configuration (shape, arrangement, etc.) of the backside gasket 5D is the same as the configuration of the frontside gasket 5U described above, but inverted vertically with respect to axis CX or axis CY.
[0067] As shown in Figures 6 to 8 and Figures 12 to 13, 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.
[0068] The back base layer 50D is laminated on the back placement section 25D. More specifically, the back base layer 50D comprises two back first base layers 50Da and a back second base layer 50Db. The two back first base layers 50Da are each laminated on the back first placement section 25Da. The back second base layer 50Db is laminated on the back second placement section 25Db.
[0069] The first back seal portion 52D is laminated on the lower surface of the first back base layer 50Da. The first back seal portion 52D is located below the first back groove portion 27Da. The two first back seal portions 52D each extend along the outer edge of the first back base layer 50Da. The two first back seal portions 52D individually surround the first manifolds 20La and 20Rb. When viewed from above, the first back seal portion 52D has an annular (endless annular) shape. As shown in Figure 12, the first back seal portion 52D is elastically in contact with the water electrolysis member 6 (shown by a dotted line in Figure 12) which is laminated adjacent to the lower side of the back bipolar plate 2D.
[0070] The second seal portion 53D on the back side is laminated on the lower surface of the second base layer 50Db on the back side. The second seal portion 53D on the back side is located below the second groove portion 27Db on the back side. The second seal portion 53D on the back side extends along the outer edge of the second base layer 50Db 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. When viewed from the top and bottom, the second seal portion 53D on the back side exhibits an annular (endless annular) shape. As shown in Figure 12, the second seal portion 53D on the back side is elastically in contact with the water electrolysis member 6 laminated adjacent to the lower side of the back side bipolar plate 2D.
[0071] As shown in Figures 6 and 8, the two rear-side connecting portions 51D are formed in the rear-side first base layer 50Da. 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.
[0072] Specifically, the rear connecting portion 51D comprises a plurality of rear protrusions 510D and a plurality of rear grooves 511D. Each of the plurality of rear protrusions 510D is located below the rear connecting groove 27Dc. The plurality of rear protrusions 510D are arranged in the front-to-back direction. The rear protrusions 510D extend in the left-to-right direction. The rear grooves 511D are flush with the rear first base layer 50Da. The rear grooves 511D are partitioned between adjacent pairs of rear protrusions 510D. The plurality of rear grooves 511D are arranged in the front-to-back direction. The rear grooves 511D extend in the left-to-right direction. The second fluid L2 flows through the rear grooves 511D.
[0073] The back side protrusion 510D protrudes downward relative to the back side groove 511D, in a vertically symmetrical manner to the front side protrusion 510U shown in Figures 12 to 13. The back side protrusion 510D elastically contacts the water electrolytic member 6, which is laminated adjacent to the lower side of the back side bipolar plate 2D.
[0074] (Regarding the vertical overlap between the front gasket 5U and the back gasket 5D) As shown in Figures 5, 8, and 14-15, when viewed from above, the front first base layer 50Ua and the two back first base layers 50Da overlap in the portion surrounding the first manifolds 20La and 20Rb. When viewed from above, the two front second base layers 50Ub and the back second base layer 50Db overlap in the portion surrounding the second manifolds 20Lb and 20Ra. The front first base layer 50Ua and the back second base layer 50Db overlap in the portion surrounding the front flow path area 21U and the back flow path area 21D.
[0075] Thus, the front base layer 50U is positioned on the ring-side of the front first seal portion 52U and the front second seal portion 53U, and includes the entire surface of the portion excluding the front sealing target portion (first manifold 20La, 20Rb, second manifold 20Lb, 20Ra, and front flow path area 21U).
[0076] Similarly, the back base layer 50D is positioned on the annular side of the back first seal portion 52D and the back second seal portion 53D, and includes the entire surface of the portion excluding the back seal target portion (first manifold 20La, 20Rb, second manifold 20Lb, 20Ra, and back flow path area 21D).
[0077] As shown by hatching in Figures 14 and 15, 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.
[0078] (Coating portion 5Mb) As shown in Figures 3, 10-12, and 14-15, 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 on the inner circumferential surface of the first manifold 20La, 20Rb connects the front first base layer 50Ua and the two back first base layers 50Da in the vertical direction. That is, the front first base layer 50Ua, the two back first base layers 50Da and the coating portion 5Mb are integrally connected. The coating portion 5Mb on the inner circumferential surface of the second manifold 20Lb, 20Ra connects the two front second base layers 50Ub and the back second base layer 50Db in the vertical direction. In other words, the two front-side second base layers 50Ub, the back-side second base layer 50Db, and the covering portion 5Mb are integrally connected.
[0079] <Water Electrolysis Component 6> Next, the configuration of the water electrolysis component 6 will be described. As shown in Figures 2 and 9, the water electrolysis component 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 (not shown), a front diffusion layer 602U, and a back diffusion layer (not shown). 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 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 is laminated on the lower surface of the back catalyst layer.
[0080] 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, and two second manifolds 20Lb, 20Ra). Each of these openings penetrates the frame portion 61 in the vertical direction.
[0081] <Manufacturing Method for Bipolar Plate 2 with Double-Sided Gaskets> Next, the manufacturing method for the bipolar plate 2 will be briefly explained. The bipolar plate 2 is manufactured by insert molding. Specifically, first, a pre-fabricated bipolar plate body 20 (with adhesive pre-applied to the portion where the gasket 5 will be molded) is placed in the cavity of a mold (not shown). Next, the gasket material is injected into the mold-clamped cavity via each manifold. Next, the mold is heated to harden the material in the cavity.
[0082] As the raw materials injected from the first manifolds 20La and 20Rb harden, the front first base layer 50Ua, two front connecting portions 51U, front first seal portion 52U, two back first base layers 50Da, two back first seal portions 52D, and two covering portions 5Mb shown in Figures 3 and 6 are integrally molded. In addition, the front first base layer 50Ua, the two back first base layers 50Da, and the two covering portions 5Mb are bonded to the bipolar plate body 20. Similarly, as the raw materials injected from the second manifolds 20Lb and 20Ra harden, the two front second base layers 50Ub, two front second seal portions 53U, back second base layer 50Db, two back connecting portions 51D, back second seal portion 53D, and two covering portions 5Mb shown in Figures 3 and 6 are integrally molded. Furthermore, the two front-side second base layers 50Ub, the back-side second base layer 50Db, and the two covering portions 5Mb are bonded to the bipolar plate body 20. After that, the bipolar plate 2, after the gasket 5 has been formed, is removed from the cavity in the open state of the mold and subjected to predetermined post-processing.
[0083] <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 a lamination process and a fastening process. As shown in Figure 1, in the lamination process, a laminate 91 is made by alternately laminating a plurality of bipolar plates 2 and a plurality of water electrolysis members 6. In the fastening process, first, a pair of end plates 90 are placed at both ends of the laminate 91 in the vertical direction. Next, the pair of end plates 90 and the laminate 91 are fastened together with a plurality of tie rods 92. The tie rods 92 apply a fastening force (pressing force) F to the laminate 91 from the vertical direction. This fastening force F causes adjacent bipolar plates 2 and water electrolysis members 6 in the vertical direction to press against each other.
[0084] <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, and the method for manufacturing the water electrolysis apparatus will be described. As shown in Figures 14 to 15, the front base layer 50U is arranged to include the entire surface of the area inside the rings of the front first seal portion 52U and the front second seal portion 53U, excluding the front sealing target portion (first manifold 20La, 20Rb, second manifold 20Lb, 20Ra, and front flow path area 21U). Therefore, the shunt current can be reduced.
[0085] Similarly, the back base layer 50D is positioned on the ring-side of the back first seal portion 52D and the back second seal portion 53D, and includes the entire surface of the portion excluding the back sealing target portion (first manifold 20La, 20Rb, second manifold 20Lb, 20Ra, and back flow path area 21D). This makes it possible to reduce shunt current.
[0086] Furthermore, according to the bipolar plate 2 of this embodiment, a single bipolar plate body 20 can secure both the front channel area 21U and the back channel area 21D. Therefore, compared to the case where a plate member dedicated to the front channel area 21U and a plate member dedicated to the back channel area 21D are used, the number of parts in the water electrolysis device 9 can be reduced. In addition, the number of parts can be reduced, which in turn reduces the assembly man-hours for the water electrolysis device 9.
[0087] As shown in Figures 3 to 5, the grooves 27U on the front side of the plate (first front groove 27Ua, second front groove 27Ub, and connecting front groove 27Uc) are covered by the front base layer 50U (first front base layer 50Ua and second front base layer 50Ub). This prevents misalignment of the front gasket 5U relative to the upper surface 20U of the base 200 of the bipolar plate body 20. Similarly, the grooves 27D on the back side of the plate (first back groove 27Da, second back groove 27Db, and connecting back groove 27Dc) are covered by the back base layer 50D (first back base layer 50Da and second back base layer 50Db). This prevents misalignment of the back gasket 5D relative to the lower surface 20D of the bipolar plate body 20. Furthermore, by suppressing misalignment, it is possible to maintain a state in which the portion of the bipolar plate body 20 where electrical insulation is to be enhanced is covered by the front gasket 5U and the back gasket 5D. This makes it possible to reduce the shunt current.
[0088] As shown in Figures 3 to 5, the first groove 27Ua on the front side extends along the first seal portion 52U on the front side. The second groove 27Ub on the front side extends along the second seal portion 53U on the front side. In other words, the first groove 27Ua and the second groove 27Ub on the front side surround the area to be sealed on the front side (first manifold 20La, 20Rb, second manifold 20Lb, 20Ra, and front flow path area 21U). Therefore, misalignment of the first seal portion 52U and the second seal portion 53U on the front side with respect to the upper surface 20U of the base portion 200 of the bipolar plate body 20 can be suppressed. Thus, the area to be sealed on the front side can be reliably sealed.
[0089] Similarly, the first groove 27Da on the back side extends along the first sealing portion 52D on the back side. Also, the second groove 27Db on the back side extends along the second sealing portion 53D on the back side. That is, the first groove 27Da and the second groove 27Db on the back side surround the parts to be sealed on the back side (first manifold 20La, 20Rb, second manifold 20Lb, 20Ra, and back side flow path area 21D). Therefore, misalignment of the first sealing portion 52D and the second sealing portion 53D on the back side with respect to the lower surface 20D of the base portion 200 of the bipolar plate body 20 can be suppressed. Thus, the parts to be sealed on the back side can be reliably sealed.
[0090] As shown in Figure 13, the front convex portion 510U and the front connecting groove portion 27Uc of the front connecting portion 51U of the back bipolar plate 2D overlap in the vertical direction. Therefore, the elastic deformation range of the front convex portion 510U in the vertical direction can be increased. Consequently, as shown in Figure 12, the elastic contact force with the reference water electrolytic member 6M can be increased. Thus, leakage of the first fluid L1 from the front groove portion 511U can be suppressed. Similarly, since the back convex portion 510D and the back connecting groove portion 27Dc overlap in the vertical direction, leakage of the second fluid L2 from the back groove portion 511D can be suppressed. In addition, the front connecting groove portion 27Uc can suppress the misalignment of the front connecting portion 51U with respect to the front arrangement portion 25U. Similarly, the back connecting groove portion 27Dc can suppress the misalignment of the back connecting portion 51D with respect to the back arrangement portion 25D.
[0091] The bipolar plate body 20 shown in Figures 4 and 7 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 12, 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, etc. Furthermore, the shunt current can be reduced.
[0092] As shown in Figures 2 and 12, the bipolar plate body 20 is equipped with a plurality of spacers 201 that protrude in the vertical direction. When viewed from the vertical direction, the spacers 201 are located on the outside of the base portion 200 (outside the rings 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). This allows for high shape stability of the bipolar plate 2. In addition, the frame portion 61 of the water electrolysis member 6 shown in Figure 2 has higher rigidity than the electrolysis portion 60. This allows for high shape stability of the electrolyte membrane 600 of the electrolysis portion 60.
[0093] As shown in Figure 12, the fastening force F causes the spacer 201 to press against the frame portion 61 (i.e., the high-rigidity portion) of a pair of water electrolytic members 6 adjacent to each other in the vertical direction. This increases the shape stability of the laminate 91. It also prevents the fastening force F from being excessively applied to the electrolytic section 60. Therefore, the shape stability of the electrolytic section 60 (electrolyte membrane 600, front catalyst layer 601U, front diffusion layer 602U, back catalyst layer, back diffusion layer, etc.) can be increased. Furthermore, the spacer 201 defines the amount of compression of the front gasket 5U and the back gasket 5D. This prevents the front gasket 5U and the back gasket 5D from being excessively compressed.
[0094] The electrolyte membrane 600 shown in Figure 2 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).
[0095] 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 shown in Figure 2 is unlikely to occur. Consequently, non-precious metal materials can be used as catalysts. Thus, the manufacturing cost of the water electrolysis device 9 can be reduced.
[0096] As shown in Figure 12, 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 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 electrolytic member 6M. This improves the sealing performance of the front-side connecting portion 51U.
[0097] Similar to the case of the front-side connecting portion 51U of the back-side bipolar plate 2D described above, when viewed from above, 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 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.
[0098] As shown in Figures 2-3, 5-6, 8, 10, and 12-15, 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. Similarly, the back connecting portion 51D ensures a flow path for the second fluid L2 between the second manifolds 20Lb, 20Ra and the back flow path area 21D.
[0099] 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. For example, the shape of the portion of the front arrangement portion 25U corresponding to the front connecting portion 51U, and the shape of the portion of the back arrangement portion 25D corresponding to the back connecting portion 51D, can each be made into a flat surface without irregularities.
[0100] The bipolar plate 2 in this embodiment is manufactured by insert molding. Therefore, the molding of the gasket 5 and the joining of the gasket 5 to the bipolar plate body 20 can be performed simultaneously. In addition, each manifold (first manifold 20La, 20Rb, second manifold 20Lb, 20Ra) can be used as the raw material injection section into the cavity. Therefore, the structure of the mold is simpler compared to the case where the gate is arranged separately from the manifold in the mold.
[0101] In the manufacturing method of the water electrolysis device 9 of this embodiment, a laminate 91 is manufactured in the 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.
[0102] <Other> The embodiments of the double-sided gasketed bipolar plate, the water electrolysis apparatus equipped with the double-sided gasketed bipolar plate, and the method for manufacturing the water electrolysis apparatus 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.
[0103] Figure 16 shows a partial cross-sectional view in the vertical direction of a bipolar plate with double-sided gaskets according to another embodiment. Note that Figure 16 shows the portion corresponding to Figure 13 (the cross-sectional view in the XIII-XIII direction of Figure 10). The same reference numerals are used for parts corresponding to those in Figure 13.
[0104] As shown in Figure 16, the front surface arrangement portion 25U includes a front surface base portion 25Uc. Viewed from the top and bottom, the front surface base portion 25Uc overlaps with the front surface connecting portion 51U. The front surface base portion 25Uc has an uneven shape (rectangular wave shape) with undulations in the vertical direction. Specifically, the front surface base portion 25Uc includes a plurality of front surface protrusions 250Uc and a plurality of front surface grooves 251Uc. The plurality of front surface protrusions 250Uc are arranged in the front-to-back direction. The front surface protrusions 250Uc extend in the left-to-right direction.
[0105] The front-side connecting portion 51U is provided with a front-side first base layer 50Ua of constant thickness. By covering the above-mentioned uneven shape (front-side protrusions 250Uc, front-side grooves 251Uc) with the front-side first base layer 50Ua, the uneven shape is transferred to the front-side first base layer 50Ua. Using this transfer, the front-side protrusions 510U and front-side grooves 511U are arranged on the front-side connecting portion 51U. Thus, according to the bipolar plate of this embodiment, the front-side protrusions 510U and front-side grooves 511U can be arranged on the front-side connecting portion 51U by utilizing the uneven shape of the front-side base portion 25Uc. Similarly, the back-side protrusions 510D and back-side grooves 511D can be arranged on the back-side connecting portion 51D by utilizing the uneven shape of the back-side base portion (not shown) (see Figure 6). In addition, the front-side base portion 25Uc can suppress misalignment of the front-side connecting portion 51U relative to the front-side arrangement portion 25U. Similarly, the back base portion can suppress misalignment of the back connecting portion 51D relative to the back placement portion 25D (see Figure 6).
[0106] 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), the seal part (front first seal part 52U, front second seal part 53U, back first seal part 52D, back second seal part 53D), and the manifold (first manifold 20La, 20Rb, second manifold 20Lb, 20Ra).
[0107] 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.
[0108] The use of adhesive in insert molding 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. Even without adhesive, since the front gasket 5U and the back gasket 5D are connected via the covering portion 5Mb, the back gasket 5D can suppress the peeling of the front gasket 5U from the upper surface 20U. Similarly, the front gasket 5U can suppress the peeling of the back gasket 5D from the lower surface 20D. Therefore, the bipolar plate body 20 and the gasket 5 can be integrated without using adhesive.
[0109] 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.
[0110] The material of the bipolar plate body 20 is not particularly limited as long as it is a conductive material. Conductive materials include, for example, metals and composite materials of conductive materials and resins. Metals with excellent corrosion resistance, such as stainless steel, titanium, copper, magnesium, and aluminum, are suitable for long-term use. The manufacturing method of the bipolar plate body 20 is not particularly limited. Forging, casting, injection molding (in the case of the above composite materials), etc., may be used.
[0111] 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.
[0112] 2: Bipolar plate, 2D: Backside bipolar plate, 2U: Frontside bipolar plate 20: Bipolar plate body, 20La: First manifold, 20Lb: Second manifold, 20Ra: Second manifold, 20Rb: First manifold, 200: Base, 201: Spacer 20D: Bottom surface (backside), 21D: Backside flow path area, 25D: Backside arrangement section, 25Da: Backside first arrangement section, 25Db: Backside second arrangement section, 27D: Plate backside groove section, 27Da: Backside first groove section, 27Db: Backside second groove section, 27Dc: Backside connecting groove section 20U: Top surface (surface), 21U: Front side flow path area, 25U: Front side placement area, 25Ua: Front side first placement area, 25Ub: Front side second placement area, 25Uc: Front side base area, Front side protrusion 250Uc, Front side groove 251Uc, 27U: Plate front side groove, 27Ua: Front side first groove, 27Ub: Front side second groove, 27Uc: Front side connecting groove 5: Gasket 5D: Back side gasket, 50D: Back side base layer, 50Da: Back side first base layer, 50Db: Back side second base layer, 51D: Back side connecting area, 510D: Back side protrusion, 511D: Back side groove, 52D: Back side first seal area, 53D: Back side second seal area 5U: Front gasket, 50U: Front base layer, 50Ua: Front first base layer, 50Ub: Front second base layer, 51U: Front connecting part, 510U: Front protrusion, 511U: Front groove, 52U: Front first seal part, 53U: Front second seal part 5Mb: Covering part 6: Water electrolysis component, 6M: Reference water electrolysis component, 60: Electrolysis part, 600: Electrolyte membrane, 601U: Front catalyst layer, 602U: Front diffusion layer, 61: Frame part 9: Water electrolysis device, 90: End plate, 91: Laminate, 92: Tie rod C: Center of gravity, CX: Axis, CY: Axis, F: Fastening force, L1: First fluid, L2: Second fluid, O: Gasket overlap part
Claims
1. A metal bipolar plate body is provided, 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 through which the first fluid flows and a front arrangement portion arranged on the surface, and a back flow path area through which the second fluid flows and a back arrangement portion arranged on the back surface, and a gasket having an elastomer front gasket arranged on the front arrangement portion and an elastomer back gasket arranged on the back arrangement portion, wherein the front gasket has a front base layer laminated on the front arrangement portion, a front first seal portion protruding from the front base layer to the front side and surrounding the first manifold and the front flow path area, a front second seal portion protruding from the front base layer to the front side and surrounding the second manifold, and a front connecting portion arranged on the front base layer and connecting the first manifold and the front flow path area, Viewed from the front-back direction, the front base layer is located on the ring-inside of the front first seal portion and the front second seal portion, and is arranged over the entire surface of the portion excluding the first manifold, the second manifold, and the front flow path area. The back gasket has a back base layer laminated on the back arrangement portion, a back first seal portion protruding from the back base layer to the back and surrounding the first manifold, a back second seal portion protruding from the back base layer to the back and surrounding the second manifold and the back flow path area, and a back connecting portion arranged on the back base layer and connecting the second manifold and the back flow path area. A double-sided gasketed bipolar plate, viewed from the front-back direction, the back base layer is located on the ring-inside of the back first seal portion and the back second seal portion, and is arranged over the entire surface of the portion excluding the first manifold, the second manifold, and the back flow path area.
2. The double-sided gasketed bipolar plate according to claim 1, wherein the front-side arrangement portion has a plurality of plate-side grooves covered by the front-side base layer, and the back-side arrangement portion has a plurality of plate-side grooves covered by the back-side base layer.
3. The double-sided gasketed bipolar plate according to claim 2, wherein the groove portion on the front side of the plate has a front connecting groove portion, the groove portion on the back side of the plate has a back connecting groove portion, the front connecting portion has a plurality of front protrusions arranged on the front side of the front connecting groove portion and a front groove portion partitioned between a pair of adjacent front protrusions through which the first fluid flows, and the back connecting portion has a plurality of back protrusions arranged on the back side of the back connecting groove portion and a back groove portion partitioned between a pair of adjacent back protrusions through which the second fluid flows.
4. The front-side arrangement portion has a front-side base portion with an uneven shape that overlaps the front-side connecting portion when viewed from the front-back direction, the front-side base layer has an uneven shape that follows the uneven shape of the front-side base portion, the front-side connecting portion has a front-side convex portion and a front-side groove portion partitioned between an adjacent pair of the front-side convex portions through which the first fluid flows, the front-side convex portion and the front-side groove portion are arranged utilizing the uneven shape of the front-side base layer, the back-side arrangement portion has a back-side base portion with an uneven shape that overlaps the back-side connecting portion when viewed from the front-back direction, the back-side base layer has an uneven shape that follows the uneven shape of the back-side base portion, the back-side connecting portion has a back-side convex portion and a back-side groove portion partitioned between an adjacent pair of the back-side convex portions through which the second fluid flows, The double-sided gasketed bipolar plate according to claim 1, wherein the back side protrusion and the back side groove are arranged utilizing the uneven shape of the back side base layer.
5. The double-sided gasketed bipolar plate according to claim 1, 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 bipolar plate body has spacers protruding in the front-back direction, and when viewed from the front-back direction, the spacers are arranged on the outer rings 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, as described in claim 1.
7. 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.
8. The water electrolysis apparatus according to claim 7, 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.
9. 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, wherein the back gasket of the front bipolar plate and the front gasket of the back bipolar plate are provided with at least one of the following configurations A and B: (Configuration A) When viewed from the lamination direction, at least a part of the back connecting portion of the front bipolar plate and at least a part of the front gasket of the back bipolar plate overlap each other. (Configuration B) When viewed from the lamination direction, at least a part of the front connecting portion of the back bipolar plate and at least a part of the back gasket of the front bipolar plate overlap each other.
10. 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 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.