Separator for fuel cell and fuel cell stack

Abstract

The invention provides a fuel cell separator and a fuel cell stack. A fuel cell separator is provided with a pair of plates which are joined to each other so as to form a cooling medium flow path through which a cooling medium flows therein. Each of the pair of plates has: a first flow path forming section that forms a gas flow path in a space between the membrane electrode assembly and the outer surface of the separator; a sealing part protruding toward a structure including the membrane electrode assembly so as to cut off communication between a communication hole provided in the separator and the gas flow path; a duct part that is provided so as to intersect the sealing part and protrudes toward the structure so as to form a communication flow path that communicates the communication hole and the cooling medium flow path; and a second flow path forming part which is connected with the hole path part and forms a connection flow path.

Description

Technical Field

[0001] The present invention relates to a separator for a fuel cell and a fuel cell stack. Background Art

[0002] In recent years, in order to ensure that more people can use cost-effective, reliable, sustainable and advanced energy, technology development related to fuel cells that contribute to energy efficiency is being carried out. This fuel cell has a fuel cell stack composed of a structure including a joint body of an electrolyte membrane and an electrode and a separator alternately stacked, but as a separator assembled in this fuel cell stack, it is known in the past that there is a separator composed of a pair of metal plates joined and a cooling medium flow channel for the cooling medium to flow is formed between the pair of metal plates. Such a separator is recorded in Patent Document 1, for example.

[0003] The partition described in Patent Document 1 is provided with a connecting hole for a cooling medium inlet and a connecting hole for a cooling medium outlet on one side and the other side of the cooling medium flow channel, and metal bead seals are respectively provided around these connecting holes. Furthermore, in the partition, holes are respectively provided to intersect these metal bead seals, and the cooling medium flow channel and the connecting holes are connected via the holes.

[0004] In the separator described in Patent Document 1, the pair of metal plates are formed into substantially flat plates in the central region of the coolant flow channel and in the region between the channels. Therefore, the pair of metal plates have low rigidity, and the separator is prone to bend or deform.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent No. 7038692 (JP7038692B). Summary of the invention

[0008] A technical solution of the present invention is a fuel cell separator that is alternately stacked with a structure including a membrane electrode assembly as an assembly of an electrolyte membrane and an electrode and constitutes a fuel cell stack together with the structure, and includes a pair of metal plates, the pair of plates being configured to have inner surfaces facing each other and outer surfaces on the opposite sides of the inner surfaces, and to have connecting holes that form a supply flow channel and a discharge flow channel for a cooling medium, respectively, and to be joined to each other to form a cooling medium flow channel for the cooling medium to flow between the pair of inner surfaces. The separator includes a first region facing the assembly, a second region around the connecting hole, and a third region between the first region and the second region. A pair of plates respectively have: a concave-convex first flow channel forming portion, which is arranged in the first area and forms a gas flow channel in the space between the joint body and the outer surface; a sealing portion, which is arranged in the second area and protrudes toward the structure in a manner of cutting off the connection between the connecting hole and the space; a channel portion, which is arranged crosswise with the sealing portion and protrudes toward the structure in a manner of forming a connecting flow channel connecting the connecting hole and the cooling medium flow channel; and a concave-convex second flow channel forming portion, which is arranged in the third area in a manner connected to the channel portion to form a connecting flow channel as a part of the cooling medium flow channel.

[0009] A fuel cell stack according to another aspect of the present invention includes a plurality of structures including a membrane electrode assembly as an assembly of an electrolyte membrane and an electrode, and the plurality of fuel cell separators alternately stacked on the plurality of structures. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] The objects, features and advantages of the present invention will be further clarified through the following description of the embodiments in conjunction with the accompanying drawings.

[0011] Figure 1 It is a perspective view schematically showing the overall structure of a fuel cell stack according to an embodiment of the present invention.

[0012] Figure 2 is along Figure 1 A cross-sectional view taken along line II-II.

[0013] Figure 3 It is shown Figure 1 A three-dimensional diagram showing the schematic structure of an integrated electrode assembly included in a fuel cell stack.

[0014] Figure 4A This is a rear view of a fuel cell separator according to an embodiment of the present invention.

[0015] Figure 4B It is a front view of a fuel cell separator according to an embodiment of the present invention.

[0016] Figure 5 yes Figure 4A , Figure 4B A cross-sectional view of the main parts of the partition.

[0017] Fig. 6A is along Figure 4A Cross-sectional view taken along line AA.

[0018] Figure 6B is along Figure 4B Cross-sectional view taken along line BB.

[0019] Figure 7 yes Figure 4A Enlarged view of Part VII.

[0020] Figure 8 is along Figure 7 A cross-sectional view taken along line VIII-VIII.

[0021] Fig. 9 is along Figure 7 A cross-sectional view taken along line IX-IX.

[0022] Fig.10 It is shown Figure 7 FIG. 1 is a diagram of a modified example of .

[0023] Fig.11 It is shown Figure 7 FIG. 1 is a diagram of other modified examples of . DETAILED DESCRIPTION

[0024] Below, refer to Figures 1 to 11 The embodiment of the present invention is described. The fuel cell stack of the embodiment of the present invention is a main component of the fuel cell and is included in the fuel cell. The fuel cell is installed in a vehicle, for example, to generate electric power for driving the vehicle. In addition to being installed in mobile objects other than vehicles such as aircraft and ships, and robots, the fuel cell can also be installed in various industrial machines.

[0025] First, the overall structure of a fuel cell stack will be briefly described. Figure 1 1 is a perspective view schematically showing the overall structure of a fuel cell stack 100 according to an embodiment of the present invention. For convenience, as shown in the figure, three mutually orthogonal axes are defined as the front-to-back direction, the left-to-right direction, and the up-to-down direction, and the structure of each part is explained according to this definition. These directions are not necessarily consistent with the front-to-back direction, the left-to-right direction, and the up-to-down direction of the vehicle. For example, Figure 1 The front-to-back direction may be the front-to-back direction of the vehicle, may be the left-to-right direction, and may be the up-down direction.

[0026] like Figure 1As shown, the fuel cell stack 100 has a battery stack 101 formed by stacking a plurality of power generation cells 1 in the front-to-back direction and end units 102 disposed at both ends of the battery stack 101, and is generally in a rectangular parallelepiped shape. The length of the battery stack 101 in the left-right direction is longer than that in the up-down direction. For convenience, Figure 1 A single power generation cell 1 is shown. The power generation cell 1 includes an integrated electrode assembly 2 having a membrane electrode assembly including an electrolyte membrane and electrodes, and separators 3, 3 arranged on both front and rear sides of the integrated electrode assembly 2. The integrated electrode assemblies 2 and separators 3 are alternately arranged in the front-rear direction.

[0027] Figure 2 This is a cross-sectional view of the main part of the central part of the battery stack 101 in the left-right direction (along the Figure 1 sectional view taken along line II-II). Figure 2 As shown, the partition 3 has a front plate 3F and a rear plate 3R, which are a pair of metal thin plates with a corrugated cross-section. The front plate 3F extends in the up-down, left-right directions and has a front surface 3Fa and a rear surface 3Fb. The rear plate 3R extends in the up-down, left-right directions and has a front surface 3Ra and a rear surface 3Rb. The rear surface 3Fb of the front plate 3F and the front surface 3Ra of the rear plate 3R, which are opposite to each other, are joined to each other at the outer peripheral edges by welding or the like. Thus, the front plate 3F and the rear plate 3R are integrated to form the partition 3. The partition 3 uses a conductive material with excellent corrosion resistance, for example, stainless steel, titanium, titanium alloy, etc.

[0028] A cooling channel PAw for the flow of a cooling medium is formed inside the partition 3 surrounded by the front plate 3F and the rear plate 3R, that is, between the rear surface 3Fb of the front plate 3F and the front surface 3Ra of the rear plate 3R. The power generation surface of the power generation cell 1 is cooled by the flow of the cooling medium. As the cooling medium, water can be used, for example. The partition is formed into a concave-convex shape by stamping and the like to form a gas flow channel between the surface (front surface 3Fa and rear surface 3Rb) of the partition 3 facing the integrated electrode assembly 2 and the integrated electrode assembly 2. In more detail, the partition 3 has: a front and rear pair of ribs 3A, 3A, which protrude toward the integrated electrode assembly 2; and a front and rear pair of recesses 3B, 3B, which are connected to the front and rear pair of ribs 3A, 3A and are formed into a concave shape. The front and rear pair of recesses 3B, 3B abut against each other.

[0029] The front and rear pair of ribs 3A, 3A abut against the front surface 2a and the rear surface 2b of the integrated electrode assembly 2. When assembling the fuel cell stack 100, a compressive load F is applied to the cell stack 101 in the front-to-back direction, and after the fuel cell stack 100 is assembled, the compressive load F is maintained. Therefore, a predetermined surface pressure generated by the compressive load F in the front-to-back direction acts on the integrated electrode assembly 2 through the ribs 3A.

[0030] Between the front surface 2a of the integrated electrode assembly 2 and the rear plate 3R of the separator 3 opposite to the front surface 2a, an anode flow channel PAa for the fuel gas to flow is formed by the recess 3B. Between the rear surface 2b of the integrated electrode assembly 2 and the front plate 3F of the separator 3 opposite to the rear surface 2b, a cathode flow channel PAc for the oxidant gas to flow is formed by the recess 3B. For example, hydrogen can be used as the fuel gas, and for example, air can be used as the oxidant gas. In the case where the fuel gas and the oxidant gas are not distinguished, they are sometimes referred to as reaction gases.

[0031] Figure 3 2 is a perspective view showing the schematic structure of the integrated electrode assembly 2. Figure 3 As shown, the integrated electrode assembly 2 includes a substantially rectangular membrane electrode assembly 20 and a frame 21 that supports the membrane electrode assembly 20. Figure 2 As shown in the detailed view of the portion A of FIG. 2 , the membrane electrode assembly 20 includes an electrolyte membrane 23 , an anode electrode 24 provided on a front surface 231 of the electrolyte membrane 23 , and a cathode electrode 25 provided on a rear surface 232 of the electrolyte membrane 23 .

[0032] The electrolyte membrane 23 is, for example, a solid polymer electrolyte membrane, and a thin film of a perfluorosulfonic acid polymer containing water can be used. The electrolyte membrane is not limited to a fluorine-based electrolyte membrane, and a hydrocarbon-based electrolyte membrane can also be used.

[0033] The anode electrode 24 includes: an electrode catalyst layer 241, which is formed on the front surface 231 of the electrolyte membrane 23 and serves as a reaction field for the electrode reaction; and a gas diffusion layer 242, which is provided on the front surface of the electrode catalyst layer 241 and diffuses and supplies the fuel gas. An intermediate layer (base layer) may be provided between the electrode catalyst layer 241 and the gas diffusion layer 242. The cathode electrode 25 includes: an electrode catalyst layer 251, which is formed on the rear surface 232 of the electrolyte membrane 23 and serves as a reaction field for the electrode reaction; and a gas diffusion layer 252, which is provided on the rear surface of the electrode catalyst layer 251 and diffuses and supplies the oxidant gas. An intermediate layer (base layer) may be provided between the electrode catalyst layer 251 and the gas diffusion layer 252.

[0034] The electrode catalyst layers 241 and 251 include a catalyst metal that promotes the electrochemical reaction between hydrogen contained in the fuel gas and oxygen contained in the oxidant gas, an electrolyte (ionomer, etc.) having proton conductivity, and carbon particles having electron conductivity. The gas diffusion layers 242 and 252 are composed of a conductive member having gas permeability, such as a carbon porous body. Since the gas diffusion layers 242 and 252 are mainly composed of carbon and fluorine, they have a waterproof function.

[0035] In the anode electrode 24, the fuel gas (hydrogen) supplied through the anode flow channel PAa is ionized by the action of the catalyst and moves to the cathode electrode side through the electrolyte membrane 23. The electrons generated at this time are taken out as electrical energy through the external circuit. In the cathode electrode 25, the oxidant gas (oxygen) supplied through the cathode flow channel PAc reacts with the hydrogen ions introduced from the anode electrode 24 and the electrons moved from the anode electrode 24 to generate water. The generated water gives appropriate humidity to the electrolyte membrane 23, and the remaining water is discharged to the outside of the integrated electrode assembly 2 along the flow of the gas.

[0036] Figure 3 The frame 21 is a thin plate in a substantially rectangular shape and is made of insulating resin, rubber, etc. A substantially rectangular opening 21a is provided in the central portion of the frame 21. The membrane electrode assembly 20 is provided in a manner covering the entire opening 21a, and the peripheral portion of the membrane electrode assembly 20 is supported by the frame 21. On the left side of the opening 21a of the frame 21, three through holes 211 to 213 are provided in parallel in the vertical direction and penetrate the frame 21 in the front-to-back direction, and on the right side of the opening 21a, three through holes 214 to 216 are provided in parallel in the vertical direction and penetrate the frame 21 in the front-to-back direction.

[0037] like Figure 1 As shown, the separators 3 at the front and rear of the integrated electrode assembly 2 are provided with through holes 301 to 306 penetrating the separators 3 in the front-to-back direction at positions corresponding to the through holes 211 to 216 of the frame 21. The through holes 301 to 306 are respectively connected to the through holes 211 to 216 of the frame 21. Through the collection of these interconnected through holes 211 to 216, 301 to 306, flow channels PA1 to PA6 (indicated by arrows for convenience) are formed that penetrate the battery stack 101 and extend in the front-to-back direction. The flow channels PA1 to PA6 are sometimes also referred to as manifolds. The flow channels PA1 to PA6 are connected to the manifold outside the fuel cell stack 100.

[0038] The flow channel PA1 (solid arrow) extending forward through the through holes 211 and 301 is a fuel gas supply flow channel. The flow channel PA6 (solid arrow) extending backward through the through holes 216 and 306 is a fuel gas exhaust flow channel. The fuel gas supply flow channel PA1 and the fuel gas exhaust flow channel PA6 are connected to the anode flow channel PAa ( Figure 2 ) is connected, and as shown by the solid arrow, the fuel gas flows in the left-right direction through the anode flow channel PAa via the fuel gas supply flow channel PA1 and the fuel gas exhaust flow channel PA6. The connection between the anode flow channel PAa and the other flow channels PA2 to PA5 is cut off by the weld bead described later.

[0039] The flow channel PA4 (dashed arrow) extending forward through the through holes 214 and 304 is the oxidant gas supply flow channel. The flow channel PA3 (dashed arrow) extending backward through the through holes 213 and 303 is the oxidant gas exhaust flow channel. The oxidant gas supply flow channel PA4 and the oxidant gas exhaust flow channel PA3 are connected to the cathode flow channel PAc ( Figure 2 ) is connected, and as shown by the dotted arrow, the oxidant gas flows through the cathode flow channel PAc in the left and right direction via the oxidant gas supply flow channel PA4 and the oxidant gas exhaust flow channel PA3. The connection between the cathode flow channel PAc and the other flow channels PA1, PA2, PA5, and PA6 is cut off by the weld bead described later.

[0040] The flow channel PA5 (single-dot chain arrow) extending forward through the through holes 215 and 305 is a cooling medium supply flow channel. The flow channel PA2 (single-dot chain arrow) extending backward through the through holes 212 and 302 is a cooling medium discharge flow channel. The cooling medium supply flow channel PA5 and the cooling medium discharge flow channel PA2 are connected to the cooling flow channel PAw ( Figure 2 ) is connected, and the cooling medium flows through the cooling channel PAw via the cooling medium supply channel PA5 and the cooling medium discharge channel PA2. The connection between the cooling channel PAw and other channels PA1, PA3, PA4, and PA6 is cut off by the weld bead described later.

[0041] The end units 102 disposed on both the front and rear sides of the battery stack 101 respectively include a terminal plate 4, an insulating plate 5, and an end plate 6. The terminal plate 4 is a substantially rectangular plate-shaped member made of metal and has a terminal portion for extracting the electricity generated by the electrochemical reaction in the battery stack 101. The insulating plate 5 is a substantially rectangular plate-shaped member made of non-conductive resin or rubber and electrically insulates the terminal plate 4 and the end plate 6.

[0042] The end plates 6 are plate-shaped members made of metal or high-strength resin. A pair of end plates 6, 6 are fixed to a connecting member elongated in the front-to-back direction, for example, by bolts, and the front and rear end plates 6, 6 are connected to each other via the connecting member. The fuel cell stack 100 is held in a state where the end plates 6, 6 are pressed in the front-to-back direction via the connecting member. Thus, the compressive load F( Figure 2 ) acts on the integrated electrode assembly 2 and the separator 3. The shell surrounding the battery stack 101 can be used as a connecting member, and the front and rear end plates 6, 6 can be fixed to the front and rear ends of the shell, respectively.

[0043] A plurality of through holes 102a to 102f are provided in the end unit 102 on the rear side, penetrating the end unit 102 in the front-to-back direction. The through hole 102a is provided on the extension line of the fuel gas supply flow channel PA1, and is connected to the fuel gas supply flow channel PA1. The through hole 102b is provided on the extension line of the cooling medium exhaust flow channel PA2, and is connected to the cooling medium exhaust flow channel PA2. The through hole 102c is provided on the extension line of the oxidant gas exhaust flow channel PA3, and is connected to the oxidant gas exhaust flow channel PA3. The through hole 102d is provided on the extension line of the oxidant gas supply flow channel PA4, and is connected to the oxidant gas supply flow channel PA4. The through hole 102e is provided on the extension line of the cooling medium supply flow channel PA5, and is connected to the cooling medium supply flow channel PA5. The through hole 102f is provided on the extension line of the fuel gas exhaust flow channel PA6, and is connected to the fuel gas exhaust flow channel PA6.

[0044] In more detail, a fuel gas tank storing high-pressure fuel gas is connected to the through hole 102a via an ejector, an injector, etc., and fuel gas is supplied to the fuel cell stack 100 via the through hole 102a. The fuel gas is discharged from the through hole 102f. A compressor for supplying oxidant gas is connected to the through hole 102d, and the oxidant gas compressed by the compressor is supplied to the fuel cell stack 100 via the through hole 102d. The oxidant gas is discharged from the through hole 102c. A pump for supplying a cooling medium is connected to the through hole 102e, and a cooling medium is supplied to the fuel cell stack 100 via the through hole 102e. The cooling medium is discharged from the through hole 102b. The discharged cooling medium is cooled by heat exchange in the radiator and is supplied to the fuel cell stack 100 again via the through hole 102e.

[0045] The above is a schematic structure of the fuel cell stack 100. The fuel cell stack 100 is housed in a substantially box-shaped casing and mounted on a vehicle. The fuel cell stack 100 of this embodiment is characterized by the structure of the separator 3 assembled in the fuel cell stack 100. The structure of the separator 3 is described in more detail below.

[0046] Figure 4A is a rear view of the partition 3 (viewed from the rear), Figure 4B is a front view (viewed from the front) of the partition 3. In other words, Figure 4A The rear surface 3Rb ( Figure 2 ), Figure 4B The front surface 3Fa ( Figure 2 )’s picture. Figure 4A , Figure 4B All of them are views viewed from the front side of the partition plate 3 .

[0047] In the following, when the separator 3 is viewed from the front, for the sake of convenience, the membrane electrode assembly 20 ( Figure 3 ) opposite to the power generation surface, that is, the area AR1 opposite to the power generation surface is called the active area of ​​the partition 3, and the area outside the active area is called the inactive area. Since the active area AR1 is located in the center of the partition 3 in the left-right direction, the active area AR1 is sometimes also called the central area of ​​the partition 3.

[0048] For convenience, the left-right end region of the non-active region where the through holes 301 to 306 are provided is referred to as the end region AR2 of the partition 3. The end region AR2 includes flow passages PA1 to PA6 for supplying and discharging reaction gas and cooling medium. For convenience, the left-right inner region of the end region AR2 in the non-active region is referred to as the connection region AR3 of the partition 3. The connection region AR3 is located between the active region AR1 and the left and right end regions AR2.

[0049] like Figure 4A As shown, in the active area AR1 of the rear plate 3R, although a part is omitted in the figure, a plurality of convex parts 307 are provided protruding toward the rear at equal intervals in the vertical direction in substantially the entire area. The plurality of convex parts 307 extend in the left-right direction, respectively, and concave parts 308 (equivalent to the concave parts) are provided between the convex parts 307, 307 adjacent to each other in the vertical direction. Figure 2 Anode flow channel PAa ( Figure 2 ). On the rear surface 3Rb of the rear plate 3R, a plurality of embossed portions 371 are provided at equal intervals in the vertical direction on the right and left sides of the convex portion 307. More specifically, in the inlet region and the outlet region of the anode flow channel PAa, a plurality of embossed portions 371 are provided in a substantially cylindrical shape protruding from the rear surface 3Rb of the rear plate 3R toward the rear. Figure 4A In the figure, one row of embossed portions 371 is shown in the vertical direction, but a plurality of rows of embossed portions 371 may be provided. The embossed portions 371 may also be omitted.

[0050] like Figure 4B As shown, in the active area AR1 of the front plate 3F, although a part is omitted in the figure, a plurality of convex parts 309 are provided protruding forward at equal intervals in the vertical direction in substantially the entire area. The plurality of convex parts 309 extend in the left-right direction, respectively, and a concave part 310 (equivalent to a concave part) is provided between the convex parts 309 and 309 adjacent in the vertical direction. Figure 2 A cathode flow channel PAc ( Figure 2). On the front surface 3Fa of the front plate 3F, a plurality of embossed portions 372 are provided at equal intervals in the vertical direction on the right and left sides of the convex portion 309. More specifically, in the inlet region and the outlet region of the cathode flow channel PAc, a plurality of embossed portions 372 are provided protruding forward from the front surface 3Fa of the front plate 3F. Figure 4B Although one row of embossed portions 372 is shown in the vertical direction, a plurality of rows of embossed portions 372 may be provided. The embossed portions 372 may also be omitted.

[0051] like Figure 4A As shown, a plurality of weld beads for sealing, i.e., metal weld bead seals, are provided on the rear surface 3Rb of the rear plate 3R and protrude rearward toward the frame 21. The plurality of weld beads include an outer weld bead 31, an inner weld bead 32, and an end weld bead 33, which are formed by stamping the rear plate 3R.

[0052] When viewed from the front of the partition plate 3, the outer bead portion 31 extends along the periphery of the rear plate 3R in a manner that surrounds the entire through holes 301 to 306, and is generally rectangular in shape. The end bead portions 33 are provided only for the number of through holes 301 to 306. The plurality of end bead portions 33 are respectively provided in a generally rectangular shape corresponding to the shapes of the through holes 301 to 306, and each independently surrounds one of the plurality of through holes 301 to 306. The inner bead portion 32 is provided on the inner side of the outer bead portion 31. More specifically, the inner bead portion 32 extends in a zigzag shape through the left-right outer side of the end bead portion 33 around the through holes 301, 303, 304, and 306, and through the left-right inner side of the end bead portion 33 around the through holes 302 and 305. The end bead portion 33 around the through holes 302 and 305 is located between the outer bead portion 31 and the inner bead portion 32.

[0053] like Figure 4B As shown, the front surface 3Fa of the front plate 3F is provided with a plurality of bead portions for sealing that protrude forward toward the frame 21. The plurality of bead portions include an outer bead portion 34, an inner bead portion 35, and an end bead portion 36, which are formed by stamping the front plate 3F.

[0054] When viewed from the front of the partition plate 3, the outer bead portion 34 extends along the periphery of the front plate 3F in a manner that surrounds the entire through holes 301 to 306, and is generally rectangular in shape. The end bead portion 36 is provided only for the number of through holes 301 to 306. The plurality of end bead portions 36 are respectively provided in a generally rectangular shape corresponding to the shapes of the through holes 301 to 306, and each independently surrounds one of the plurality of through holes 301 to 306. The inner bead portion 35 is provided on the inner side of the outer bead portion 34. More specifically, the inner bead portion 35 extends in a zigzag shape through the left-right outer side of the end bead portion 36 around the through holes 301, 303, 304, and 306, and through the left-right inner side of the end bead portion 36 around the through holes 302 and 305. The end bead portion 36 around the through holes 302 and 305 is located between the outer bead portion 34 and the inner bead portion 35.

[0055] Figure 5 FIG. 2 is a cross-sectional view of the main part of the separator 3 vertically cutting the weld bead portions 31 to 36. Figure 5 As shown, the weld beads 31 to 36 have a substantially rectangular cross-section, or more specifically, a substantially trapezoidal cross-section. The plurality of weld beads 31 to 33 of the rear plate 3R and the plurality of weld beads 34 to 36 of the front plate 3F are arranged at the same positions in the vertical and horizontal directions when viewed from the front. Therefore, a substantially rectangular space SP0 is provided between the weld beads 31 to 33 and the weld beads 34 to 36.

[0056] The seal 40 is fixed to the rear surface of the weld bead portions 31 to 33 and the front surface of the weld bead portions 34 to 36. The seal 40 is made of elastic material such as rubber or resin. The front seal 40 is fixed to the frame 21 ( Figure 3 ) is pressed by the rear surface 2b of the frame 21, and the rear seal 40 is pressed by the front surface 2a of the frame 21. As a result, the gap between the weld bead portions 31 to 36 and the frame 21 is blocked, and a sealed anode flow channel PAa and cathode flow channel PAc can be formed between the integrated electrode assembly 2 and the separator 3. It should be noted that the seal 40 can also be omitted so that the top end of the weld bead portions 31 to 36 directly abuts against the frame 21.

[0057] The anode flow channel PAa and the cathode flow channel PAc are provided inside the inner bead portions 32 and 35 when viewed from the front of the separator 3. A plurality of through holes 301, 303, 304, and 306 are arranged inside the inner bead portions 32 and 35. However, the connection between the anode flow channel PAa and the through holes 301, 303, 304, and 306 is cut off by the end bead portion 33, and the connection between the cathode flow channel PAc and the through holes 301, 303, 304, and 306 is cut off by the end bead portion 36. In the present embodiment, a plurality of channel portions perpendicularly intersecting (crossing) the end bead portion 33 are provided in the separator 3 so that the anode flow channel PAa and the through holes 301 and 306 and the cathode flow channel PAc and the through holes 303 and 304 are connected, respectively.

[0058] In more detail, Figure 4A As shown, in the end bead portion 33 around the through hole 301 of the rear plate 3R, the right end bead portion 33 extending in the vertical direction is crossed in the left-right direction, and a plurality of (for example, three) channel portions 41 are parallel to each other and are evenly spaced in the vertical direction. In the end bead portion 33 around the through hole 303, the right end bead portion 33 extending in the vertical direction is crossed in the left-right direction, and a plurality of (for example, three) channel portions 42 are parallel to each other and are evenly spaced in the vertical direction. In the end bead portion 33 around the through hole 304, the left end bead portion 33 extending in the vertical direction is crossed in the left-right direction, and a plurality of (for example, three) channel portions 43 are parallel to each other and are evenly spaced in the vertical direction. In the end bead portion 33 around the through hole 306, the left end bead portion 33 extending in the vertical direction is crossed in the left-right direction, and a plurality of (for example, three) channel portions 44 are parallel to each other and are evenly spaced in the vertical direction.

[0059] Likewise, if Figure 4B As shown, the end bead portion 36 around the through hole 301 of the front plate 3F makes the right end bead portion 36 extending in the vertical direction intersect in the left-right direction, and a plurality of (for example, three) channel portions 45 are parallel to each other and are evenly spaced in the vertical direction. The end bead portion 36 around the through hole 303 makes the right end bead portion 36 extending in the vertical direction intersect in the left-right direction, and a plurality of (for example, three) channel portions 46 are parallel to each other and are evenly spaced in the vertical direction. The end bead portion 36 around the through hole 304 makes the left end bead portion 36 extending in the vertical direction intersect in the left-right direction, and a plurality of (for example, three) channel portions 47 are parallel to each other and are evenly spaced in the vertical direction. The end bead portion 36 around the through hole 306 makes the left end bead portion 36 extending in the vertical direction intersect in the left-right direction, and a plurality of (for example, three) channel portions 48 are parallel to each other and are evenly spaced in the vertical direction.

[0060] The number of the above-mentioned channel portions 41 to 48 is an example, and each channel portion 41 to 48 may be more than 3 or less than 3. The channel portions 41 to 44 of the rear plate 3R and the channel portions 45 to 48 of the front plate 3F are arranged at the same positions when viewed from the front of the partition plate 3. The channel portions 41 to 48 extend substantially linearly in the left-right direction, respectively, and their protrusions in the front-to-back direction, widths in the up-down direction, and lengths in the left-to-right direction are equal to each other. The channel portions 41 to 48 are formed by stamping the front plate 3F and the rear plate 3R.

[0061] Fig. 6A is a cross-sectional view showing the structure of the channel portions 41 and 45 near the through hole 301 (along the Figure 4A AA line cut through the cross section). Fig. 6A As shown, the hole portion 45 of the front plate 3F is set to be convex toward the front, and the hole portion 41 of the rear plate 3R is set to be convex toward the rear. The protrusion amount of the hole portions 41 and 45 in the front-to-back direction is smaller than the protrusion amount of the weld portions 33 and 36. Although omitted from the figure, the hole portions 41 and 45 are roughly rectangular or trapezoidal in cross section, and a connecting flow channel PA11 is formed between the front and rear hole portions 41 and 45.

[0062] In the channel portions 41 and 45, the left side of the weld bead portions 33 and 36 (the through hole 301 side) is called the outer channel portion 411 and 451, and the right side of the weld bead portions 33 and 36 (the anode flow channel PAa side) is called the inner channel portion 412 and 452. The left end of the outer channel portion 411 and 451 is located at the periphery of the through hole 301, and the left end surface of the communication flow channel PA11 is open to the through hole 301. The right end of the outer channel portion 411 and 451 passes through the weld bead portions 33 and 36 and communicates with the internal space of the weld bead portions 33 and 36.

[0063] The left end of the inner channel portion 412, 452 passes through the weld portions 33, 36 and communicates with the internal space of the weld portions 33, 36. A tapered portion 412a, 452a whose protrusion toward the right gradually decreases is provided at the right end portion of the inner channel portion 412, 452. At the right end of the channel portion 41, 45, the protrusion in the front-to-back direction is 0, and the connecting flow channel PA11 is blocked. A fuel gas outflow port 410 is provided in the tapered portion 412a of the channel portion 41. Thus, the through hole 301 is connected to the anode flow channel PAa behind the rear plate 3R via the connecting flow channel PA11 and the outflow port 410. Therefore, as Fig. 6A As shown by the arrows, the fuel gas flowing through the through hole 301 can be supplied to the anode flow channel PAa via the communication flow channel PA11 and the outlet 410 .

[0064] Although not shown in the figure, the channel portions 44 and 48 near the through hole 306 are Fig. 6AThe holes 41 and 45 are similarly constructed. That is, the holes 41 and 45 and the holes 44 and 48 are symmetrical about the axis extending in the vertical direction. Therefore, the inlet 440 ( Figure 4A ) is opened in the tapered portion at the left end of the port portion 44. Thus, the fuel gas flowing through the anode flow channel PAa is introduced into the through hole 306 via the inlet 440 and the connecting flow channel PA11 inside the port portions 44 and 48.

[0065] Figure 6B is a cross-sectional view showing the structure of the channel portions 43 and 47 near the through hole 304 (along the Figure 4B BB line cut through the cross-sectional view). Figure 6B As shown, the hole portion 47 of the front plate 3F is set to be convex toward the front, and the hole portion 43 of the rear plate 3R is set to be convex toward the rear. The protrusion amount of the hole portions 43 and 47 in the front-to-back direction is smaller than the protrusion amount of the weld portions 33 and 36. Although omitted from the figure, the hole portions 43 and 47 are roughly rectangular or trapezoidal in cross section, and a connecting flow channel PA12 is formed between the front and rear hole portions 43 and 47.

[0066] In the channel portions 43 and 47, the right side of the weld bead portions 33 and 36 (the through hole 304 side) is called the outer channel portion 431 and 471, and the left side of the weld bead portions 33 and 36 (the cathode flow channel PAc side) is called the inner channel portion 432 and 472. The right end of the outer channel portion 431 and 471 is located at the periphery of the through hole 304, and the right end surface of the communication flow channel PA12 is open to the through hole 304. The left end of the outer channel portion 431 and 471 passes through the weld bead portions 33 and 36 and communicates with the internal space of the weld bead portions 33 and 36.

[0067] The right end of the inner channel portion 432, 472 passes through the weld bead portion 33, 36 and communicates with the internal space of the weld bead portion 33, 36. A tapered portion 432a, 472a whose protrusion toward the left gradually decreases is provided at the left end of the inner channel portion 432, 472. At the left end of the channel portion 43, 47, the protrusion in the front-to-back direction is 0, and the connecting flow channel PA12 is blocked. The outlet 470 for the oxidant gas is opened in the tapered portion 472a of the channel portion 47. Thus, the through hole 304 is connected to the cathode flow channel PAc in front of the front plate 3F via the connecting flow channel PA12 and the outlet 470. Therefore, as Figure 6B As shown by the arrow, the oxidant gas flowing through the through hole 304 can be supplied to the cathode flow path PAc via the communication flow path PA12 and the outlet 470.

[0068] Although not shown in the figure, the channel portions 42 and 46 near the through hole 303 are Figure 6BThe hole portions 43 and 47 are similarly configured. That is, the hole portions 43 and 47 are symmetrical with the hole portions 42 and 46 about the axis extending in the vertical direction. Therefore, the inlet 460 ( Figure 4B ) is opened in the tapered portion of the right end of the port portion 46. Thus, the oxidant gas flowing through the cathode flow channel PAc is introduced into the through hole 303 via the inlet 460 and the connecting flow channel PA12 inside the port portions 42 and 46.

[0069] like Figure 4A , Figure 4B As shown in FIG. 1 , in the front plate 3F and the rear plate 3R, a plurality of channel portions 51 to 54 are provided near the through holes 302 and 305 to intersect with the weld portions 32, 33, 35, and 36. Figure 4A As shown, in the rear plate 3R, on the right side of the through hole 302, a plurality of (for example, three) channel portions 51 intersect (orthogonally) with the right end bead portion 33 extending in the vertical direction and the inner bead portion 32 extending in the vertical direction, and are arranged parallel to each other and at equal intervals in the vertical direction. In addition, on the left side of the through hole 305, a plurality of (for example, three) channel portions 52 intersect (orthogonally) with the left end bead portion 33 extending in the vertical direction and the inner bead portion 32 extending in the vertical direction, and are arranged parallel to each other and at equal intervals in the vertical direction.

[0070] Likewise, if Figure 4B As shown, in the front plate 3F, on the right side of the through hole 302, a plurality of (for example, three) channel portions 53 intersect (are orthogonal to) the right side end bead portion 36 extending in the vertical direction and the inner side bead portion 35 extending in the vertical direction, and are arranged parallel to each other and at equal intervals in the vertical direction. In addition, on the left side of the through hole 305, a plurality of (for example, three) channel portions 54 intersect (are orthogonal to) the left side end bead portion 36 extending in the vertical direction and the inner side bead portion 35 extending in the vertical direction, and are arranged parallel to each other and at equal intervals in the vertical direction.

[0071] The number of the above-mentioned channel portions 51 to 54 is an example, and the channel portions 51 to 54 may be more or less than 3. The channel portions 51 and 52 of the rear plate 3R and the channel portions 53 and 54 of the front plate 3F are arranged at the same positions when viewed from the front of the partition plate 3. The channel portions 51 to 54 extend linearly in the left-right direction, respectively, and their protrusions in the front-to-back direction, widths in the up-down direction, and lengths in the left-to-right direction are equal to each other.

[0072] like Figure 4A , Figure 4BAs shown, on the front plate 3F and the rear plate 3R, a plurality of substantially cylindrical embossed portions 373 and 374 are provided at equal intervals in the vertical direction on the outside of the embossed portions 371 and 372 in the left-right direction. The protruding directions of the embossed portions 373 and 374 are opposite to the protruding directions of the embossed portions 371 and 372. That is, the embossed portion 373 is provided to protrude forward (on the cooling flow channel side) from the front surface 3Ra of the rear plate 3R, and the embossed portion 374 is provided to protrude backward (on the cooling flow channel side) from the rear surface 3Fb of the front plate 3F.

[0073] The embossed portions 373 and 374 may be arranged on the inner side of the embossed portions 371 and 372 in the left-right direction. Figure 4A , Figure 4B In the figure, one row of embossed parts 373 and 374 is shown in the vertical direction, but a plurality of rows of embossed parts 373 and 374 may be provided. In this case, the embossed parts 371 and 372 and the embossed parts 373 and 374 may be alternately arranged in the left-right direction. The embossed parts 373 and 374 may also be omitted.

[0074] Figure 7 The invention comprises a channel portion 52. Figure 4A The main part of the enlarged view (enlarged view of part VII), Figure 8 is along Figure 7 A cross-sectional view taken along line VIII-VIII. Figure 7 For the sake of convenience, the symbols of the parts of the front plate 3F corresponding to the parts of the rear plate 3R (for example, the hole portion 54 corresponding to the hole portion 52, etc.) are shown together. Figure 8 As shown, the channel portion 54 of the front plate 3F is set to be convex toward the front, and the channel portion 52 of the rear plate 3R is set to be convex toward the rear. The protrusion amount of the channel portions 52 and 54 in the front-to-back direction is smaller than the protrusion amount of the end weld portions 33 and 36 and the inner weld portions 32 and 35. Although omitted from the figure, the channel portions 52 and 54 are roughly rectangular or trapezoidal in cross section, and a connecting flow channel PA21 is formed between the front and rear channel portions 52 and 54.

[0075] In the channel portions 52 and 54, the right side (through hole 305 side) of the end bead portions 33 and 36 is called the outer channel portion 521 and 541, and the left side (cooling flow channel PAw side) of the inner bead portions 32 and 35 is called the inner channel portion 522 and 542. The portion between the end bead portions 33 and 36 and the inner bead portions 32 and 35 is called the middle channel portion 523 and 543. The right end of the outer channel portion 521 and 541 is located at the periphery of the through hole 305, and the right end surface of the communication flow channel PA21 is open to the through hole 305. The left end of the outer channel portion 521 and 541 passes through the end bead portions 33 and 36 and communicates with the internal space of the end bead portions 33 and 36.

[0076] The right end of the middle channel portion 523, 543 passes through the end bead portion 33, 36 and communicates with the internal space of the end bead portion 33, 36. The left end of the middle channel portion 523, 543 passes through the inner bead portion 32, 35 and communicates with the internal space of the inner bead portion 32, 35. The right end of the inner channel portion 522, 542 passes through the inner bead portion 32, 35 and communicates with the internal space of the inner bead portion 32, 35. The left end of the inner channel portion 522, 542 is provided with a tapered portion 522a, 542a whose protrusion amount gradually decreases toward the left. The left ends of the inner channel portions 522, 542 are separated from each other in the front-to-back direction in a state where a predetermined amount of gap CL1 is left, and in this state, the front plate 3F and the rear plate 3R extend toward the left.

[0077] Thus, the through hole 305 is connected to the cooling flow channel PAw on the left side of the channel portion 52, 54 via the connecting flow channel PA21 and the gap CL1. Figure 8 As shown by the arrows, the cooling medium flowing through the through hole 305 can be supplied to the cooling flow channel PAw via the communication flow channel PA21 and the gap CL1. Figure 7 As shown, the channel portions 52 and 54 are arranged such that the outer channel portions 521 and 541, the middle channel portions 523 and 543, and the inner channel portions 522 and 542 are arranged on a straight line extending in the left-right direction. As a result, the pressure loss of the connecting flow channel PA21 is small, and the cooling medium flowing through the through hole 305 can be smoothly introduced into the cooling flow channel PAw.

[0078] Although not shown in the figure, the channel portions 51 and 53 near the through hole 302 are Figure 8 The hole portions 52 and 54 are similarly constructed. That is, the hole portions 51 and 53 and the hole portions 52 and 54 are bilaterally symmetrical about the axis extending in the vertical direction through the middle portion of the partition plate 3 in the horizontal direction. Therefore, a gap CL1 in the front-to-back direction for the cooling medium to flow is provided at the right end of the hole portions 51 and 53. As a result, the cooling medium flowing through the cooling flow channel PAw is introduced into the through hole 302 via the gap CL1 at the right end of the hole portions 51 and 53 and the connecting flow channel PA21 inside the hole portions 51 and 53.

[0079] like Figure 4A , Figure 4B As shown, the cooling channel PAw is a region including the active region AR1, and is provided from the connecting region AR3 on the left of the channel portions 52 and 54 to the connecting region AR3 on the right of the channel portions 51 and 53. Figure 7As shown, in the connection area AR3, a plurality of ribs 55 for restricting the flow direction of the cooling medium are provided on the rear plate 3R and the front plate 3F, respectively. The positions of the ribs 55 of the rear plate 3R in the up-down, left-right directions are the same as the positions of the ribs 55 of the front plate 3F in the up-down, left-right directions. The plurality of ribs 55 have the same shape when viewed from the front of the partition plate 3, and their protrusions in the front-back direction and the widths in the up-down direction are equal to each other.

[0080] Fig. 9 is along Figure 7 The cross-sectional view taken along the IX-IX line. Fig. 9 As shown in FIG. 1 , the rib 55 of the rear plate 3R protrudes forward from the front surface 3Ra of the rear plate 3R, and the rib 55 of the front plate 3F protrudes backward from the rear surface 3Fb of the front plate 3F. Figure 8 The weld bead portions 32, 33, 35, 36 and the hole portions 52, 54 are protrudingly arranged in the front-rear opposite directions. The rib portion 55 has a substantially rectangular cross-section, and more specifically, a substantially trapezoidal cross-section.

[0081] The front end surface of the rib 55 of the rear plate 3R and the rear end surface of the rib 55 of the front plate 3F abut against each other, and a flow channel (called a connecting flow channel) PA22 of the cooling medium is formed between the ribs 55 and 55 arranged in the vertical direction. At this time, the rib 55 constitutes a side wall or a partition wall of the connecting flow channel PA22, and the cooling medium flows along the rib 55.

[0082] like Figure 7 As shown, when viewed from the front of the partition plate 3, the ribs 55 are provided between the channel portions 52, 54 arranged in the vertical direction, above the channel portions 52, 54 at the top, and below the channel portions 52, 54 at the bottom. These multiple ribs 55 are arranged parallel to each other and extend in the left-right direction. The lengths of the multiple ribs 55 in the left-right direction are equal to each other, and the positions in the left-right direction are also equal to each other.

[0083] The right end of the rib 55 is located to the left of the left ends of the channel portions 52 and 54 at a predetermined distance. The left end of the rib 55 is located to the left of the embossed portions 373 and 374 ( Figure 4A , Figure 4B ) or is located to the right at a prescribed distance from the right end of the gas flow channels PAa and PAc. The distance from the right end of the rib 55 to the end area AR2 is shorter than the distance from the left end of the rib 55 to the active area AR1, and the rib 55 is provided near the right side (channel side) in the connection area AR3. The distance from the right end of the rib 55 to the end area AR2 and the distance from the left end of the rib 55 to the active area AR1 can be equal to each other. It is also possible to omit the embossed portions 373 and 374 and provide the rib 55 over the entire left-right direction of the connection area AR3.

[0084] By providing the rib 55 in this way, the connecting flow passage PA22 is located on the extension line of the connecting flow passage PA21 inside the hole portion 52, 54. In other words, the connecting flow passage AR21 and the connecting flow passage AR22 are located on the same straight line. Figure 7 As shown by the dotted arrow, the cooling medium flowing through the connecting flow passage PA21 flows through the connecting flow passage PA22 without changing the flow direction. Therefore, the cooling medium flows smoothly in the connecting area AR3, and the cooling effect generated by the flow of the cooling medium can be improved.

[0085] Although detailed illustration is omitted, ribs 55 are also provided on the right side of the channel portions 51 and 53. That is, the ribs 55 on the right side of the channel portions 51 and 53 and the ribs 55 on the left side of the channel portions 52 and 54 are bilaterally symmetrical about the axis extending in the vertical direction through the middle part of the partition plate 3 in the horizontal direction. Therefore, a connecting flow channel PA22 is provided between the ribs 55 and 55 adjacent in the vertical direction and arranged at equal intervals in the vertical direction on the right side of the channel portions 51 and 53. Thus, the cooling medium flowing through the cooling flow channel PAw is introduced into the through hole 302 via the connecting flow channel PA22 and the connecting flow channel PA21.

[0086] As described above, the rear end surface of the rib 55 of the front plate 3F and the front end surface of the rib 55 of the rear plate 3R abut against each other ( Fig. 9 ). As a result, the rigidity of the partition plate 3 in the connection area AR3 is improved, and the deflection and deformation of the partition plate 3 can be suppressed. Specifically, the partition plate 3 can be prevented from being deflected by the compressive load F in the front-to-back direction when assembling the fuel cell stack 100. As a result, the sealing performance of the contact portion between the partition plate 3 and the frame 21 can be ensured.

[0087] According to this embodiment, the following effects can be achieved.

[0088] (1) The separator 3 of this embodiment is configured as a fuel cell separator, which is alternately stacked with the integrated electrode assembly 2 and constitutes the fuel cell separator of the fuel cell stack 100 together with the integrated electrode assembly 2. Figure 1 , Figure 2 ), the integrated electrode assembly 2 includes a membrane electrode assembly 20 which is a joint body of an electrolyte membrane 23, an anode electrode 24, and a cathode electrode 25. The separator 3 includes a front plate 3F and a rear plate 3R (a pair of plates made of metal joined to each other) Figure 2 The front plate 3F has a rear surface 3Fb opposite to the rear plate 3R and a front surface 3Fa on the opposite side thereof, and the rear plate 3R has a front surface 3Ra opposite to the front plate 3F and a rear surface 3Rb on the opposite side thereof ( Figure 2The front plate 3F and the rear plate 3R are provided with a through hole 305 forming a flow channel for supplying the cooling medium and a through hole 302 forming a flow channel for discharging the cooling medium, respectively, and a cooling flow channel PAw for the cooling medium to flow is formed between the rear surface 3Fb of the front plate 3F and the front surface 3Ra of the rear plate 3R which are opposed to each other. Figure 2 The separator 3 includes an active region (first region) AR1 facing the membrane electrode assembly 20, an end region (second region) AR2 around the through holes 302 and 305, and a connection region (third region) AR3 between the active region AR1 and the end region AR2. Figure 4A , Figure 4B ).

[0089] The front plate 3F has: a convex portion 309 and a concave portion 310, which are arranged in the active area AR1 to form a cathode flow channel PAc in the space between the membrane electrode assembly 20 and its front surface 3Fa; weld portions 35, 36, which are arranged in the end area AR2 and protrude toward the frame 21 of the integrated electrode assembly 2 in a manner of cutting off the connection between the through holes 302, 305 and the cathode flow channel PAc; channel portions 53, 54, which are arranged crosswise with the weld portions 35, 36 to protrude toward the frame 21 in a manner of forming a connecting flow channel PA21 connecting the through holes 302, 305 and the cooling flow channel PAw; and a rib portion 55, which is arranged in the connecting area AR3 in a manner connected to the channel portions 53, 54 to form a connecting flow channel PA22 ( Figure 4B , Figure 7 , Figure 8 ). The rear plate 3R has: a convex portion 307 and a concave portion 308, which are arranged in the active area AR1 to form an anode flow channel PAa in the space between the membrane electrode assembly 20 and its rear surface 3Rb; weld portions 32, 33, which are arranged in the end area AR2 and protrude toward the frame 21 of the integrated electrode assembly 2 in a manner of cutting off the connection between the through holes 302, 305 and the anode flow channel PAa; and hole portions 51, 52, which are arranged crosswise with the weld portions 32, 33 to protrude toward the frame 21 in a manner of forming a connecting flow channel PA21 connecting the through holes 302, 305 and the cooling flow channel PAw; and a rib portion 55, which is arranged in the connection area AR3 in a manner connected to the hole portions 51, 52 to form a connecting flow channel PA22 as a part of the cooling flow channel PAw ( Figure 4A , Figure 7 , Figure 8 ).

[0090] By providing the ribs 55 on the partition plate 3 in this way, the rigidity of the partition plate 3 is improved, and the deflection and deformation of the partition plate 3 can be suppressed. As a result, the sealing performance of the contact portion between the partition plate 3 and the frame 21 can be ensured. In contrast, in the connection area AR3, if the front plate 3F and the rear plate 3R are configured as simple flat plates, for example, when a compressive load F acts in the front-rear direction, the partition plate 3 may be deflected and deformed, and sufficient sealing performance cannot be ensured.

[0091] (2) The rib 55 is provided so that the connecting flow passage PA22 extends along the extension line of the communicating flow passage PA21 ( Figure 7 ). As a result, the cooling medium flowing through the connecting flow channel PA21 flows smoothly through the connecting flow channel PA22 (the inlet side of the cooling flow channel PAw), and the cooling medium flowing through the connecting flow channel PA22 flows smoothly through the connecting flow channel PA21 (the outlet side of the cooling flow channel PAw). Therefore, the pressure loss of the flow of the cooling medium is small, and the cooling effect can be improved.

[0092] (3) The ribs 55 of the front plate 3F and the ribs 55 of the rear plate 3R protrude from the rear surface 3Fb and the front surface 3Ra, respectively, and abut against each other to form a side wall portion (side wall or partition wall) of the connecting flow passage PA22. By making the ribs 55 abut against each other in this way, the rigidity of the connecting area AR3 of the partition plate 3 with respect to the compressive load F in the front-rear direction is further improved.

[0093] (4) The channel portions 51 to 54 are provided so as to extend substantially straight from one end to the other end of the communicating channel PA21. Figure 4A , Figure 4B , Figure 7 ). Thus, the cooling medium can smoothly flow through the communication flow path PA21, thereby efficiently introducing the cooling medium from the through hole 305 to the connection area AR3, and from the connection area AR3 to the through hole 302.

[0094] (5) The rib 55 is provided to connect the connecting flow passage PA22 and the communicating flow passage PA21 and extend in a substantially straight line. Figure 7 ). With this structure, the cooling medium flows straightly from the through hole 305 to the left end of the right connecting flow channel PA22, and flows straightly from the right end of the left connecting flow channel PA22 to the through hole 302. Therefore, the flow loss of the cooling medium from the through hole 305 to the through hole 302 can be suppressed to a minimum.

[0095] (6) The fuel cell stack 100 includes: an integrated electrode assembly 2 including a membrane electrode assembly 20 which is an assembly of an electrolyte membrane 23, an anode electrode 24, and a cathode electrode 25; and a plurality of separators 3 ( Figure 1). Such a fuel cell stack 100 is subjected to a compressive load F in the front-rear direction during assembly. However, by providing the ribs 55 on the separator 3, the rigidity of the separator 3 is improved, and the deflection and deformation of the separator 3 can be suppressed.

[0096] The above embodiment can be modified in various ways. Several modified examples are described below. In the above embodiment, the rib 55 is provided in the connection area AR3 of the partition plate 3 as a second flow channel forming portion to form a flow channel for the cooling medium (connection flow channel PA22), but a concave-convex flow channel forming portion can be further provided to form a flow channel for the reaction gas. Fig.10 3 is a diagram showing an example of the structure of the rib 55 around the through hole 302 in this case. Fig.10 In the embodiment, a fuel gas is supplied from the through hole 301 ( Figure 1 ) flows to the anode flow channel PAa through a concave-convex flow channel PA23. The flow channel PA23 passes through the right side of the rib 55, and the area where the flow channel PA23 is provided expands downward. The rib 55 is formed so as to gradually become longer downward in a manner that does not interfere with the flow channel PA23. In this way, the lengths of the multiple ribs 55 can also be different from each other. It should be noted that regardless of whether the flow channel PA23 is provided, the lengths of the multiple ribs 55 can also be different from each other.

[0097] In the above embodiment, the through holes 301 to 306 of the partition plate 3 are configured in a substantially rectangular shape, but the shapes of the through holes 301 to 306 can be various shapes such as other polygonal, circular, and a mixture of straight and curved lines. The number and arrangement of the through holes 301 to 306 are not limited to the above. In the above embodiment, the plurality of ribs 55 are arranged parallel to each other, but they may not be parallel to each other. Fig.11 FIG. 5 is a diagram showing an example of the rib 55 around the through hole 302 configured in this way. Fig.11 In the embodiment, a portion of the periphery of the through hole 302 is in a curved shape when viewed from the front, and the channel portion 51 and the ribs 55 extend perpendicularly relative to the periphery. Therefore, the multiple ribs 55 are not in a parallel relationship. It should be noted that the multiple ribs 55 may not be parallel regardless of whether the periphery of the through hole 302 is in a curved shape. The extending direction of the ribs 55 may not be a direction perpendicular to the periphery of the through hole 302. In the above embodiment, the multiple ribs 55 are arranged at equal intervals, but they may not be arranged at equal intervals.

[0098] In the above embodiment, the width of the connecting flow channel PA21 and the width of the connecting flow channel PA22 are made constant over the entire length of the flow channels PA21 and PA22, but they may also vary in the length direction of the flow channels PA21 and PA22. For example, the rib 55 may be configured to be inclined in the vertical direction when viewed from the front of the partition 3 in such a manner that the width of the connecting flow channel PA22 on the upstream side of the cooling flow channel PAw gradually expands toward the downstream side in the flow direction of the cooling medium. The rib 55 may also be configured to be inclined in the vertical direction when viewed from the front of the partition 3 in such a manner that the width of the connecting flow channel PA22 on the downstream side of the cooling flow channel PAw gradually decreases toward the downstream side in the flow direction of the cooling medium. In the above embodiment, the channel portions 51 to 54 extend from one side of the rectangular periphery of the through holes 302 and 305, but the channel portions may also extend from multiple sides (for example, two intersecting sides). In this case, the directions in which the channel portions extend from each side may be different from each other or the same.

[0099] In the above embodiment, the connecting flow passage PA22 is formed in a straight line, but a part or all of it may be formed in a curved line. In the above embodiment, the connecting flow passage PA21 inside the channel portions 51 to 54 and the connecting flow passage PA22 on the inner side in the left-right direction thereof are connected via the gap CL1 between the pair of plates 3F and 3R, but it may be connected to the gap CL1 between the pair of plates 3F and 3R. Fig. 6A , Figure 6B Similarly, through holes are provided in the plates 3F and 3R to connect the connecting flow passage PA21 and the connecting flow passage PA22. In the above embodiment, the partition plate 3 has a pair of ribs 55 (convex portions) protruding from the inner surfaces (rear surface 3Fb and front surface 3Ra) of the pair of plates 3F and 3R facing each other and abutting against each other, and the side wall portion of the connecting flow passage PA22 is formed by the pair of ribs 55, but the pair of ribs may not abut against each other, and the structure of the second flow passage forming portion is not limited to the above structure.

[0100] In the above embodiment, the active area AR1 of the plates 3F and 3R is formed into a concave-convex shape, and gas flow channels PAa and PAc are formed between the membrane electrode assembly 20 and the outer surface of the plates 3F and 3R (front surface 3Fa and rear surface 3Rb), but the structure of the first flow channel forming portion is not limited to the above structure. In the above embodiment, the weld bead portions 32, 33, 35, and 36 are protruded toward the integrated electrode assembly 2 (structure) in a manner that cuts off the connection between the through holes 302 and 305 (connecting holes) and the cooling flow channel PAw (cooling medium flow channel), but the structure of the sealing portion is not limited to the above structure. In the above embodiment, the connecting flow channel PA22 extends along the extension line of the connecting flow channel PA21, but the connecting flow channel can also deviate from the extension line of the connecting flow channel.

[0101] In the above embodiment, the integrated electrode assembly 2 and the separator 3 are alternately stacked in the front-to-back direction to form a battery stack 101. The integrated electrode assembly 2 is a structure of a membrane electrode assembly 20 including an electrolyte membrane 23 and electrodes 24 and 25, but the stacking direction may also be a direction other than the front-to-back direction (for example, the up-down direction).

[0102] One or more of the above-described embodiments and modifications may be arbitrarily combined, and modifications may be combined with each other.

[0103] According to the present invention, the rigidity of the partition plate is improved, and the deflection and deformation of the partition plate can be suppressed.

[0104] The present invention has been described above in conjunction with preferred embodiments, but it should be understood by those skilled in the art that various modifications and changes can be made without departing from the scope of the claims.

Claims

1. A fuel cell separator, which is a fuel cell separator (3) alternately stacked with a structure (2) and which together with the structure (2) constitutes a fuel cell stack (100), wherein the structure (2) includes a membrane electrode assembly (20) which is a joint of an electrolyte membrane (23) and electrodes (24, 25), and the fuel cell separator is characterized in that: A pair of metal plates (3F, 3R) are provided, wherein the pair of plates (3F, 3R) are respectively provided with inner surfaces (3Fb, 3Ra) facing each other and outer surfaces (3Fa, 3Rb) on the opposite sides of the inner surfaces (3Fb, 3Ra), and are respectively provided with connecting holes (305, 302) forming a supply flow channel and a discharge flow channel for a cooling medium, and are mutually joined to form a cooling medium flow channel (PAw) for the cooling medium to flow between the pair of inner surfaces (3Fb, 3Ra). The separator (3) includes a first region (AR1) facing the membrane electrode assembly (20), a second region (AR2) around the communicating holes (305, 302), and a third region (AR3) between the first region (AR1) and the second region (AR2). The pair of plates (3F, 3R) respectively have: A concave-convex first flow channel forming portion (309, 310) is provided in the first region (AR1) and forms a gas flow channel (Pac, PAa) in a space between the membrane electrode assembly (20) and the outer surface (3Fa, 3Rb); a sealing portion (32, 33, 35, 36) disposed in the second region (AR2) and protruding toward the structure (2) in a manner of cutting off the communication between the communication hole (305, 302) and the space; A channel portion (51-54) is arranged to intersect with the sealing portion (32, 33, 35, 36) and protrudes toward the structure (2) to form a connecting flow channel (PA21) connecting the connecting hole (305, 302) and the cooling medium flow channel (Paw); and A second concavo-convex flow channel forming portion (55) is provided in the third region (PA3) in a manner connected to the hole portions (51-54) to form a connecting flow channel (PA22) as a part of the cooling medium flow channel (PAw).

2. The fuel cell separator according to claim 1, characterized in that: The second flow channel forming portion (55) is configured such that the connecting flow channel (PA22) extends along an extension line of the communicating flow channel (PA21).

3. The fuel cell separator according to claim 1 or 2, characterized in that: The second flow channel forming portions (55) of the pair of plates (3F, 3R) respectively have convex portions protruding from the inner surfaces (3Fb, 3Ra) and abutting against each other to form a side wall portion of the connecting flow channel (PA22).

4. The fuel cell separator according to claim 1 or 2, characterized in that: The hole portions (51-54) are configured such that the communication channel (PA21) extends substantially linearly from one end to the other end.

5. The fuel cell separator according to claim 4, characterized in that: The second flow channel forming portion (55) is provided to connect the connecting flow channel (PA22) and the communicating flow channel (PA21) and extend in a substantially linear shape.

6. The fuel cell separator according to claim 5, characterized in that: The channel portion (51-54) has a plurality of channel portions arranged substantially parallel to each other. The second flow channel forming portion (55) has a plurality of second flow channel forming portions corresponding to the plurality of channel portions. The plurality of second flow channel forming portions have a plurality of convex portions protruding from the inner surface (3Fb, 3Ra) and extending substantially parallel to each other to form side wall portions of a plurality of connecting flow channels (PA22).

7. The fuel cell separator according to claim 1 or 2, characterized in that: The pair of plates (3F, 3R) is configured to form a gap (CL1) between the pair of plates (3F, 3R) for communicating the communication flow passage (PA21) and the connection flow passage (PA22).

8. The fuel cell separator according to claim 1 or 2, characterized in that: The pair of plates (3F, 3R) has a plurality of protrusions (371 to 374) protruding from the inner surface (3Fb, 3Ra) to one side and the other side between the first flow path forming portion (309, 310) and the second flow path forming portion (55).

9. A fuel cell stack, characterized in that: have: A plurality of structures (2) including a membrane electrode assembly (20) which is an assembly of an electrolyte membrane (23) and electrodes (24, 25); and A plurality of fuel cell separators (3) according to claim 1 or 2, which are alternately stacked with the plurality of structures (2).

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