JP5061755B2 - Fuel cell - Google Patents

Description

  The present invention has an electrolyte membrane and separators disposed on both sides of the electrolyte membrane, and these fuel cell components are bonded and sealed between the electrolyte membrane and the fuel cell components having the separator. The present invention relates to a fuel cell provided with a sealing material having a function.

In general, a fuel cell is a device that directly converts a chemical energy of a fuel into electric energy by electrochemically reacting a fuel gas such as hydrogen as a reaction gas and an oxidant gas such as air. As such a fuel cell, for example, the following Patent Document 1 describes that a sealing material made of an adhesive is provided between fuel cell components including a membrane / electrode assembly including an electrolyte membrane and a separator. .
JP 2005-116404 A (paragraphs 0014, 0022)

  By the way, in the case of using an adhesive as a sealing material like the above-described conventional fuel cell, time for curing the adhesive is required. In addition, it is necessary to cure the adhesive in a state where the adherent parts (fuel cell constituent parts) are brought into contact with each other and the contact is maintained. However, the conventional fuel cell is not a fuel cell that takes into account the manufacturing time when a fuel cell stack is configured by laminating a plurality of single cells (unit cells) composed of a membrane / electrode assembly and a pair of separators on both sides thereof. It was.

Accordingly, the present invention provides a fuel cell in which an electrolyte membrane and separators stacked on both sides of the electrolyte membrane can be laminated and fixed in a short time even when they are laminated using a sealing material having an adhesive function. The purpose is to provide.

The present invention relates to a fuel cell comprising, as a fuel cell component , a membrane electrode assembly having an electrolyte membrane and gas diffusion layers located on both sides of the electrolyte membrane, and a separator disposed on both sides of the membrane electrode assembly. A fuel cell in which the fuel cell components are bonded to each other and provided with a sealing material having a sealing function, and the separator includes a convex portion protruding toward another fuel cell component. A concave portion surrounded by the convex portion, and the sealing material is provided at a position corresponding to the convex portion surrounding the concave portion or inside the convex portion surrounding the concave portion, and each fuel cell component is a peripheral edge projecting outwardly from the convex portion surrounding the recess, and most important, characterized in that a gap is provided between the outer peripheral end mutual this.

According to the present invention, each fuel cell component before stacking and fixing is supported in a state wider than the interval between the fuel cell components after stacking and fixing using the gap between the outer peripheral ends. In this state, by applying a load to each fuel cell component in the stacking direction, the sealing material provided on one side of the fuel cell components facing each other is brought into contact with the fuel cell component on the other side in a lump. Even in the case where a plurality of electrolyte membranes and separators located on both sides thereof are laminated, a fuel cell that can be laminated in a short time can be obtained .

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  First, the structure of the fuel cell stack 1 which is a fuel cell of a part common to or similar to all the embodiments described later of the present invention will be described with reference to FIGS. The fuel cell stack 1 of the present invention is a solid polymer electrolyte fuel cell stack, and is mounted on, for example, an automobile. However, you may use other than a motor vehicle.

  FIG. 1 is a perspective view of the fuel cell stack 1, and FIG. 2 is a side view of the fuel cell stack 1 of FIG. This fuel cell stack 1 is configured by laminating a predetermined number of unit cells 3 that are unit cells generating an electromotive voltage of about 1 V, and has a substantially rectangular parallelepiped shape as a whole. As will be described later, the stacked single cells 3 are fastened by, for example, penetrating tension rods 5, which are fasteners disposed at four corners, into the stack.

  FIG. 3 is a cross-sectional view showing a part of the structure of the single cell 3. In the single cell 3, a water repellent layer, a catalyst layer (not shown) and a gas diffusion layer 9 are arranged on the anode side and the cathode side of both main surfaces excluding the outer peripheral edge of the electrolyte membrane 7 made of an ion exchange membrane. A membrane / electrode assembly (MEA) 11 and a pair of separators 15 each having a gas flow path 13 for supplying fuel gas (hydrogen) and oxidant gas (oxygen, usually air) to the MEA 11 are sealed. It is a structure joined by an adhesive sealant 17 as a material. The adhesive sealant 17 also has a role of preventing leakage and mixing of the fuel gas and oxidant gas flowing through the single cell 3.

  The above-described MEA 11 and separator 15 constitute a fuel cell component, and the above-described adhesive sealant 17 adheres each fuel cell component to each other and has a sealing function.

  The electrolyte membrane 7 in the MEA 11 is a proton conductive ion exchange membrane formed of a solid polymer material, for example, a fluorine-based resin, exhibits good electrical conductivity in a wet state, and has a gas diffusion layer over the entire circumference. It protrudes outside 9. In addition, since the electrolyte membrane 7 is extremely thin with a thickness of several tens of μm, a reinforcing material 18 made of a resin material is pasted on both sides of the above-described projecting portion in order to improve handling.

  A gap S is provided between the outer peripheral end portion 11a of the MEA 11 including the reinforcing member 18 and the outer peripheral end portion 15a of the separator 15 and between the outer peripheral end portions 15a of the separators 15 in the single cells 3 adjacent to each other. ing.

  The gas diffusion layer 9 is composed of a porous member having sufficient gas diffusibility and conductivity, such as carbon cloth woven with yarn made of carbon fiber, carbon paper, or carbon felt.

  The water repellent layer is a layer containing, for example, polyethylene fluoroethylene and a carbon material, and the catalyst layer is made of carbon black on which platinum is supported. The catalyst layer is supported by the gas diffusion layer 9 to form an electrode, or is formed by supporting platinum as a catalyst or an alloy made of platinum and another metal on the surface of the electrolyte membrane 7.

  The separator 15 is formed of a material having sufficient conductivity, strength, and corrosion resistance. As a typical example, a metal material or a mixed material of resin and carbon can be given, but here a mixed material of resin and carbon is used.

  Both surfaces of the separator 15 have a convex portion 15b and a concave portion 15c surrounded by the convex portion 15b, and the adhesive sealant 17 described above is disposed on the outermost portion of the concave portion 15c. The recess 15c in which the adhesive sealant 17 is disposed is formed in an annular shape, and thus the adhesive sealant 17 is also annular. Further, in the recess 15c inside the portion where the adhesive sealant 17 is disposed, the cooling water is supplied to the gas flow path 13 for diverting the fuel gas and the oxidant gas, or to the opposite surface of the gas flow path 13, respectively. Therefore, the cooling water flow path 19 becomes.

  As shown in FIGS. 1 and 2, the fuel cell stack 1 includes a plurality of the single cells 3 that are stacked and a current collecting plate 21 and an end plate 23 that are sequentially disposed at both ends in the stacking direction. The laminated body composed of the plurality of single cells 3, the current collector plate 21 and the end plate 23 is tightened by applying a load in the laminating direction, and is described above in the through hole provided through the inside of the laminated body in this tightened state. The tension rod 5 is inserted, and a nut 25 is screwed and fastened to the end of the tension rod 5.

  The tension rod 5 is formed of a material having rigidity, for example, a metal material, and the surface is subjected to an insulation treatment in order to prevent an electrical short circuit between the single cells 3.

  The current collecting plate 21 is formed of a gas impermeable conductive member such as dense carbon or copper plate, and the end plate 23 is formed of an insulating material having rigidity. The two current collecting plates 21 are each provided with an output terminal 21a, and the electromotive force generated in the fuel cell stack 1 is output from the output terminal 21a to an external load.

  The above-described method of tightening the fuel cell stack 1 with the tension rod 5 does not require the tension rod 5 to pass through the inside of the laminate, and the end plates 23 may be tightened with the tension rod 5 outside the stack.

  Further, as shown in FIG. 1, an end plate 23 at one end of the fuel cell stack 1 has a fuel gas inlet 27 and outlet 29, an oxidant gas inlet 31 and outlet 33, and cooling water (cooling). Medium) An inlet 35 and an outlet 37 are provided. Each distribution flow path to fuel cell, oxidant gas and cooling water unit cell 3 communicating with each of these inlets, and each collective flow from fuel cell, oxidant gas and cooling water unit cell 3 communicating with each outlet A path is formed through the end plate 23 on one end side, the current collector plate 21 and a plurality of stacked unit cells 3.

  Each distribution channel and each collecting channel described above communicate with the corresponding ones of the gas channels 13 and 13 on the anode side and the cathode side of the separator 15 and the cooling water channel 19, respectively.

  In the fuel cell stack 1 described above, the fuel gas (hydrogen-containing gas) supplied to the anode side is hydrogen ionized in the catalyst layer and moves to the catalyst layer on the cathode side through the electrolyte membrane 7 appropriately humidified. To do.

  Electrons generated in the meantime are taken out to an external circuit and used as direct current electric energy. Since the gas diffusion layer 9 on the cathode side is supplied with an oxidant gas, for example, an oxygen-containing gas or air, the hydrogen ions, the electrons and the oxygen gas react in the catalyst layer on the cathode side. Water is produced.

  Although the temperature of the fuel cell stack 1 is also raised by the reaction heat of the fuel gas and the oxidant gas, it is necessary to cool the fuel cell stack 1 so as not to exceed the heat resistance temperature of the polymer ion exchange membrane. For cooling, the temperature of the fuel cell stack 1 is controlled by supplying cooling water to a cooling water passage 19 formed on the back surface of the gas supply surface of the separator 15.

  A seal is provided between the fuel cell components of the fuel cell stack 1 so that the supplied gas and cooling water do not leak to the outside of the fuel cell stack 1 and are not mixed in the fuel cell stack 1. The above-described adhesive sealant 17 which is an agent is provided.

  In the following embodiments, the front view is a view from the flow path direction in the straight flow path, but does not limit the flow path shape, the shape of the separator, and the arrangement direction.

[First Embodiment]
Next, an assembly apparatus for laminating and fixing one single cell 3 as described above will be described. FIG. 4 is a front sectional view showing a part of this assembling apparatus, and FIG. 5 is an exploded perspective view showing an outline of the assembling apparatus of FIG. The assembling apparatus includes a lower surface plate 39 that serves as a base when the MEA 11 that is a fuel cell component and two separators 15 are stacked as a single cell 3, and an upper surface plate 41 that is disposed on the upper side of the single cell 3. On the lower surface plate 39, a rod 43 is erected in the vicinity of the outer peripheral end portions 11a and 15a so as to surround the outer peripheral sides of the MEA 11 and the separator 15. The rod 43 has a cylindrical shape in FIG. 5, but may have a prismatic shape.

  In the following description, the separator 15 and the MEA 11 may be simply referred to as a battery component 38.

  In FIG. 5, three rods 43 are provided around the lowermost separator 15 placed on the lower plate 39, and the three rods 43 here are around the rectangular separator 15 and MEA 11. It is installed corresponding to three of the four sides.

  The upper portions of these rods 43 are movably inserted into sliding holes 41 a provided in the upper surface plate 41. Also, bolt insertion holes 41b for inserting bolts 45 shown in FIG. 9B described later are provided at the four corners of the upper surface plate 41, and screws for screwing and fastening the bolts 45 at the four corners of the lower surface plate 39. Each hole 39a is formed.

Further, a coil spring 47 is mounted on the outer periphery of the rod 43, and the tip (upper end) of the rod 43 inserted into the center of the coil spring 47 is a natural coil spring that is not compressed as shown in FIG. As shown in FIG. 4, the component catching claws 51 serving as the component catching members 51 are inserted and arranged in the coil gaps 49 formed along the central axis direction of the coil spring 47 described above. is doing. Here, the component hooking claws 51 are provided corresponding to the battery component parts 38 in order to support the battery component parts 38 sequentially laminated on the lowermost separator 15. That is, in FIG. 4, the component hooking claws 51 are provided corresponding to the MEAs and the separators 15 that are sequentially stacked on the lowermost separator 15.

  5 shows only one component catching claw 51 for one coil spring 47, and the coil spring 47 of FIG. 5 has a larger number of turns than the coil spring 47 of FIG. However, it is actually equivalent to the coil spring 47 of FIG.

  As shown in FIG. 5, the component hooking claw 51 described above is formed of a rectangular plate material, and is provided with a notch 51 a into which the rod 43 is inserted. The notch 51a is set so that one side of the rectangular short side is open and the opening is positioned on the battery component 38 side. Further, the notch 51 a is configured such that the component catching pawl 51 is held by the coil spring 47 in the coil gap 49 by making the width L smaller than the outer diameter of the coil spring 47.

  Such a component catching claw 51 is installed corresponding to all of the plurality of battery components 38 stacked on the lowermost separator 15 as described above, and is on the opening end portion of the notch 51a. The battery component 38 is supported by placing the outer peripheral ends 15a, 11a of the battery component 38 on the battery.

  The rod 43, the coil spring 47, and the component hooking pawl 51 constitute a component distance variable control mechanism. Further, the lower surface plate 39 and the upper surface plate 41 constitute a load application mechanism that applies a load by pressing and holding the fuel cell components from above and below.

  The adhesive sealant 17 is applied so as to form an annular shape on the side facing the MEA 11 of the recess 15c near the inner side (center side) of the outer peripheral end 15a of the lowermost separator 15, and the MEA 11 at a position corresponding to the recess 15c. Similarly, it is applied to the upper surface of (reinforcing material 18) so as to form an annular shape.

  When the MEA 11 to which the adhesive sealant 17 has been applied is laminated on the separator 15 that has been applied with the adhesive sealant 17 and is placed on the lower surface plate 39, this MEA 11 is used as the coil gap of the coil spring 47. It is placed on the tip of the component catching claw 51 inserted in 49. Similarly, the separator 15 laminated on the MEA 11 is placed on the tip of the upper component catching claw 51 inserted into the coil gap 49 of the coil spring 47.

  Here, as shown in FIG. 4, the distance H between the upper end surface of the adhesive sealant 17 applied to the lowermost separator 15 and the adherend surface of the MEA 11 (the lower surface of the lower reinforcing member 18) is H The spring constant of the coil spring 47 and the rigidity of the component catching claw 51 are determined so that> 0.

  As described above, since a plurality of battery components 38 are stacked, the coil gap 49 of the coil spring 47 after the stacking of the plurality of sheets is compressed in the vicinity of the lower surface plate 39 by the own weight of the battery components 38 and the component hooking claws 51. In contrast, there is a tendency to be dense, and conversely, the vicinity of the upper surface plate 41 is sparse. For this reason, the spring constant of the coil spring 47 and the rigidity of the component catching claw 51 are determined so that H> 0 at the lower end where the pitch (coil gap 49) of the coil spring 47 is the densest.

  A support mechanism for supporting each battery component 38 in a state where the above-mentioned distance H is H> 0 without using the coil spring 47 is provided, and the distance between each battery component 38 by this support mechanism is determined as a displacement sensor. The structure may be such that the variable control is performed while measuring.

  FIG. 6 shows the compression characteristics of the gas diffusion layer 9 disposed on both main surfaces of the electrolyte membrane 7. As described above, the gas diffusion layer 9 is a porous material and has compressibility with respect to a load. Moreover, since the gas diffusion layer 9 contacts the separator 15 and moves electrons, the output efficiency of the fuel cell stack 1 can be improved by reducing the contact resistance value of the contact surface. The contact resistance is sensitive to the applied load. Although it depends on the material of the separator 15 and the material of the gas diffusion layer 9, the predetermined load on the fuel cell stack 1 is set so that the contact surface pressure is 0.5 to 2.0 MPa. F (FIG. 7) is determined.

  FIG. 6 shows that the gas diffusion layer 9 is compressed by the dimension t when the load f is applied as shown in FIG. 6B from the state where the gas diffusion layer 9 is in contact with the separator 15 as shown in FIG. ing. At this time, the adhesive sealant 17 also comes into contact with the recess 15c of the separator 15 and is crushed.

  FIG. 7 shows a state in which a predetermined load F is applied to the fuel cell stack 1 using the upper surface plate 41 from the state in which each battery component 38 shown in FIG. The predetermined load F in FIG. 7 is the sum (F = f + p) of the load f shown in FIG. 6 and the load p necessary for compressing the coil spring 47.

  In the process in which the top plate 41 pushes the coil spring 47 and the battery component 38 (the uppermost separator 15 in this example), the adhesive sealant 17 and the adherent component (battery component 38) located above the adhesive sealant 17 are adhered. When the distance H to the surface is H = 0, that is, when the adhesive sealant 17 is in contact with the adherend part located thereabove and the gas diffusion layer 9 is crushed by the compression amount t, the applied load Reaches F and enters a predetermined load application state.

  In the process of applying the load, either the adhesive sealant 17 or the gas diffusion layer 9 may contact the separator 15 first or simultaneously.

  In the state where the predetermined load F is applied as shown in FIG. 7, the upper surface plate 41 and the lower surface plate 39 are fastened using the bolts 45 described above, and heat is applied by an oven or the like to cure the adhesive sealant 17. When the adhesive sealant 17 is cured, the component catching claw 51 is retracted to a position where the component catching claw 51 does not come into contact with the battery component 38, and the fastening between the upper surface plate 41 and the lower surface plate 39 is released, and the single unit of the fuel cell stack 1 is removed. Cell 3 is completed.

  8 to 10 show a method of assembling a single cell 3 or a module body in which a plurality of single cells 3 are stacked using the above assembling apparatus. 8 to 10 are simply diagrams for explaining the assembling method, and the number of battery components 38 to be stacked does not necessarily match the number corresponding to the single cell 3.

  First, as shown in FIG. 8A, one battery component 38 (here, the separator 15) is placed on the sealant application base 53, and the sealant application base 53 is placed below the sealant application base 53. By sucking air through a number of small holes (not shown) provided, the separator 15 is restrained and fixed. Thereafter, the adhesive sealant 17 is applied to a predetermined position by the dispenser 55.

  In this example, the application method using the dispenser 55 is used, but any application method may be used such as, for example, a screen printing type application device.

  The adhesive sealant 17 is applied in advance to all the battery components 38 to be modularized (except for the uppermost battery component 38) by the method shown in FIG. Process).

  Next, as shown in FIG. 8B, all the component catching claws 51 are set to the retracted position, and the front end side of the notch 51a is set to the separated retracted position that does not contact the battery component 38. The lowermost battery component 38 (separator 15) is placed on the central portion surrounded by the rods 43 on the lower surface plate 39.

  Thereafter, as shown in FIG. 8C, the lowermost component catching claw 51 is moved forward, and the battery is stacked on the battery component 38 (separator 15) on the tip of the component catching claw 51. The component 38 (MEA 11) is placed.

  Thereafter, in the same manner, the battery component 38 to be stacked on the battery component 38 (MEA 11) that has already been placed in a state where the component hook claw 51 positioned above the advanced component hook nail 51 is advanced. Is repeatedly performed on the corresponding component catching claw 51 to complete the stacking operation of a predetermined number of battery components 38 as illustrated in FIG. 9A (component stacking step).

  After that, as shown in FIG. 5, the top plate 41 is brought into the same state as FIG. 4 by inserting the rod 43 into the sliding hole 41a.

  In this state, as shown in FIG. 9B, the aforementioned predetermined load F is applied by the hydraulic press 57, and the bolt 45 is fastened in a state where the predetermined load F is applied. And in this fastening state, as shown to Fig.10 (a), it puts into oven 59, and the adhesive sealing agent 17 is hardened by giving heat (sealing material hardening process).

  FIG. 10B shows a method using a hot press 61 instead of heating in the oven 59 of FIG. In this case, the adhesive sealant 17 is cured by applying heat with a predetermined load F applied by the hot press 61.

  In the present embodiment, when the adhesive sealant 17 is completely cured, a single cell 3 or a module body in which a plurality of single cells 3 are stacked is completed. In either of the steps of FIGS. Before opening F, the component catching claw 51 is moved backward to the same position as in FIG. 8B where the component catching claw 51 does not come into contact with the battery component 38 apart.

  Then, in a state where the component catching claw 51 is moved backward, in the case of FIG. 10A, further removed from the oven 59, the bolt 45 is removed to release the predetermined load F, so that the battery component 38 can be removed. The above-described module body made of a laminate is completed.

  Finally, the current collector plate 21 and the end plate 23 shown in FIG. 1 and FIG. 2 are sequentially arranged at both ends of the module body described above, and finally fastened by using the tension rod 5. Alternatively, the fuel cell stack 1 including a module body in which a plurality of single cells 3 are stacked is completed.

  By the way, in the recent development of fuel cell stacks, a problem of improving productivity has been raised. One way to improve productivity is to reduce the stacking time of fuel cell components. As described above, the sealing material is provided between the fuel cell components. If all of the sealing materials are compression gaskets, all the components including the compression gaskets must be laminated independently, which requires enormous time.

  Therefore, by using the adhesive sealant 17 as the sealing material used in the fuel cell stack 1 as in the above-described embodiment, the fuel cell components can be joined together, and the module body and thus The manufacturing time of the fuel cell stack 1 can be shortened.

  As described above, according to the present embodiment, the battery component 38 is hooked and supported using the gap S between the outer peripheral ends 11a and 15a of the battery component 38, and each battery component 38 is supported in this supported state. On the other hand, by applying a load in the stacking direction, the adhesive sealant 17 between the battery component parts 38 can be collectively cured, and a plurality of MEAs 11 including the electrolyte membrane 7 and separators 15 located on both sides thereof can be provided. Even in the case of stacking, the adhesive sealant 17 can be compressed and bonded and fixed at a time, and the stacking operation can be performed efficiently in a short time.

  At this time, since the application of load can be released in a state where all of the adhesive sealants 17 set between the battery component parts 38 are simultaneously cured, the occurrence of uncured portions of the adhesive sealant 17 is prevented and the seal is made. Occurrence of discontinuous portions can be avoided, sealing performance can be improved, and a highly reliable module body can be obtained.

  In addition, if the adhesive sealant is applied while correcting the separator having warpage, and the adhesive sealant is uncured after being brought into contact with the MEA to be bonded, the correction will be lifted between the parts. The tension is generated in the adhesive sealant due to the floating, and the adhesive sealant is broken. However, in this embodiment, even when a sufficient time for applying the load is taken, the stacking time can be greatly shortened as compared to the method of laminating one by one.

  Further, each battery component 38 described above is polygonal when viewed from the stacking direction, the gap S is provided on each side of the polygon, and the component catching claw 51 is installed corresponding to each gap S. Each battery component 38 can be supported more stably, and the stacking operation becomes more efficient.

[Second Embodiment]
FIG. 11 is a cross-sectional view showing a part of the single cell 3A showing the second embodiment of the present invention. This single cell 3 </ b> A is provided with a protruding portion 11 b by causing the outer peripheral end portion 11 a of the MEA 11 to protrude outward from the outer peripheral end portion 15 a of the separator 15. The other structure and the manufacturing method of the single cell 3A (including a module body formed by stacking a plurality of single cells 3A) are the same as those in the first embodiment.

  Thus, in the second embodiment, the structure in which the outer peripheral end portion of at least one battery constituent component 38 among the plurality of battery constituent components 38 protrudes outward from the outer peripheral end portion of the other battery constituent components 38, and By doing so, it is possible to increase the hooking allowance by the component hooking claw 51 as much as the protruding portion 11b is provided, and the battery component 38 is more stabilized, especially when a large number of single cells 3 are stacked and joined. Since there are a plurality of single cells 3 and the weight of the parts increases, it is effective for stabilizing the parts.

  In the second embodiment, since the outer peripheral end portion 11a of the MEA 11 protrudes outward from the outer peripheral end portion 15a of the separator 15 as another fuel cell component, the protruding portions 11b are provided. Contact between the outer peripheral end portions 15a of the separator 15 positioned can be avoided to prevent an electrical short circuit between them, and the reliability of the fuel cell is improved.

  Further, in the second embodiment, the protrusion 11b of the MEA 11 may be provided over the entire outer periphery, but is provided only on a part of the outer periphery corresponding to the component catching claw 51, and the protrusion 11b is provided. The outer peripheral end portion 11a other than the provided portion has the same shape as the outer peripheral end portion 15a of the separator 15 as another fuel cell component as viewed from the stacking direction (vertical direction in FIG. 11), that is, with the MEA 11 The separator 15 has a shape that overlaps with each other except for the projecting portion 11b of the MEA 11 when viewed from the stacking direction, so that the outer shapes are equal to each other so that the MEA 11 and the separator 15 can be easily positioned relative to each other. Therefore, the relative positioning of the battery components 38 can be performed accurately without providing a portion unnecessary for the power generation function such as a positioning pin in the cell surface.

[Third Embodiment]
FIG. 12 is a cross-sectional view showing a part of a unit cell 3B showing the third embodiment of the present invention. This single cell 3B is made of a metal separator 63 made of a stainless steel plate or the like, instead of the separator 15 made of a mixed material of resin and carbon in the first embodiment and the second embodiment.

  The metallic separator 63 is formed in a concavo-convex shape by press molding, and an adhesive sealant 17 is interposed between the annular convex portion 63a on the outermost peripheral side and the MEA 11 (reinforcing material 18).

  Further, the separator 63 in the single cell 3B described above is joined and fixed to the separator 63 of another adjacent single cell 3B by a welding portion 65 to form a separator assembly 64 as a fuel cell component. Then, the outer peripheral end portions 63b of the separators 63 are joined and fixed to each other by the above-described welded portion 65, thereby forming the outer peripheral end portion 64a of the separator joined body 64, and the outer peripheral end portion 64a and the outer peripheral end portion 11a of the MEA 11. The above-described gap S is formed between the two.

  In this case, the space between the separator assembly 64 and the MEA 11 inside the position where the adhesive sealant 17 is provided becomes the gas flow path 13. A space between the two separators 63 bonded and fixed to each other serves as a cooling water flow path 19.

  The welded portion 65 in FIG. 12 is not only one linear shape along the outer peripheral end portion 64a, but, for example, as two linear welded portions 65A as shown in the plan view of FIG. Alternatively, a zigzag or corrugated weld 65B as shown in the plan view of FIG. 13B may be used.

  As described above, in the third embodiment, by using the separator 63 as a metal, the rigidity is higher than that of the separator 15 made of a mixed material of resin and carbon, and the assembly apparatus shown in FIGS. Support stability by the component catching claw 51 when using and laminating is improved, and assembly workability is improved.

  Further, by joining the separators 63 facing each other in the unit cells 3B to form the separator joined body 64, the rigidity is further increased, the assembly workability is further improved, and the joining of the separators 63 is performed by welding. By doing so, the rigidity of the joining portion is also increased, which can contribute to an improvement in assembly workability.

  Furthermore, since the outer peripheral end 63b of the separators 63 facing each other is bonded and fixed, there is a gap between the outer peripheral end 64a of the structure in which the outer peripheral end 63b is bonded to the outer peripheral end 11a of the MEA 11. S can be formed, and the outer peripheral end portion 64a can be hooked by inserting the component hooking claws 51 of the assembling apparatus shown in FIGS.

[Fourth Embodiment]
FIG. 14 is a cross-sectional view showing a part of a unit cell 3C showing the fourth embodiment of the present invention. This embodiment is different from the third embodiment of FIG. 12 in a portion that is closest to the outer peripheral end 63b among the spaces formed by joining the separators 63 to each other, that is, in a space adjacent to the outer peripheral end 63b. The separator 63 is filled with the same material stainless steel or resin material filler 67.

  As described above, according to the embodiment of FIG. 14, a plurality of spaces are formed between the two separators 63, and the filler 67 is filled in a position closest to the outer peripheral end 63b among the plurality of spaces. Therefore, the rigidity is further improved and the assembling workability is further improved as compared with the separator joined body 64 of FIG. 12 in which the separators 63 are simply joined together.

[Fifth Embodiment]
FIG. 15 is a cross-sectional view including a part of a unit cell 3D showing the fifth embodiment of the present invention. In this embodiment, the outer side surface 63c of the convex portion 63a that protrudes toward the MEA 11 of the separator 63 is opposed to the MEA 11 of the convex portion 63a rather than the inner side surface 63d of the convex portion 63a. The inclination is set to be gentle so that the inclination angle is more parallel to the flat surface 63e. The inclination angle θ of the outer side surface 63c is about 5 to 30 degrees.

  The adhesive sealant 17 is provided on the outer corner portion 63g, which is the boundary portion between the outer side surface 63c and the flat surface 63e. Note that the adhesive sealant 17 in FIG. 15 is shown as a compressed (crushed) state applied on the separator 63, and the one applied on the MEA 11 (reinforcing material 18) is not compressed (crushed). Not shown).

  According to the fifth embodiment described above, since the adhesive sealant 17 is provided at the outer corner 63g of the convex portion 63a on the outer peripheral end 63b side of the separator 63, the gas formed inside the adhesive sealant 17 A wide power generation area including the diffusion layer 9 can be secured, and when the adhesive sealant 17 is compressed and crushed, the surplus adhesive sealant is prevented from moving toward the power generation area, thereby preventing adverse effects on power generation. it can.

  Further, the angle of the outer side surface 63c of the convex portion 63a provided with the adhesive sealant 17 is more parallel to the flat surface 63e facing the MEA 11 of the convex portion 63a than the inner side surface 63d of the convex portion 63a. Therefore, even if the application position of the adhesive sealant 17 is shifted from the target position toward the outer side surface 63c due to dimensional variations of parts, the other side adhesive surface (reinforcement) of the adhesive sealant 17 is set. The distance to the material 18) can be ensured in a close state, and the adhesive sealant 17 can easily come into contact with the mating adhesive surface, thereby reducing the rate of occurrence of poor sealing performance.

[Sixth Embodiment]
FIG. 16 is a cross-sectional view including a part of a unit cell 3E showing the sixth embodiment of the present invention. In this embodiment, the outer side surface 63c of the convex portion 63a provided with the adhesive sealant 17 is set at a right angle to the flat surface 63e facing the MEA 11 of the convex portion 63a with respect to the embodiment of FIG. .

  As described above, in the sixth embodiment, the outer side surface 63c of the convex portion 63a provided with the adhesive sealant 17 is set at a right angle to the flat surface 63e facing the MEA 11 of the convex portion 63a. When the adhesive sealant 17 is compressed and crushed, the outside of the side surface 63c widens and opens, so that the surplus adhesive sealant can be easily moved in the widened outward direction to the power generation area. Therefore, it is possible to reliably prevent the movement of the excess adhesive, leading to an improvement in reliability.

  In each of the embodiments of FIGS. 15 and 16, as in the embodiment of FIG. 14, the portion closest to the outer peripheral end 63b in the space formed by joining the separators 63 to each other, that is, the outer peripheral end. The space adjacent to the part 63b may be filled with a stainless steel or resin material filler that is the same material as the separator 63.

  On the contrary, in the embodiment of FIG. 14, the side surface 63c outside the convex portion 63a as in the embodiments of FIGS. 15 and 16 may be used. You may provide in the outer corner | angular part 63g like a form.

[Seventh Embodiment]
17 and 18 relate to the seventh embodiment of the present invention, and this embodiment shows an example in which four single cells 3B shown in FIG. 12 are stacked to form a module. That is, here, five separator assemblies 64 and four MEAs 11 are bonded together using the adhesive sealant 17 to manufacture a module body 69 as shown in FIG. .

  As described above, according to the seventh embodiment, when a single cell 3B composed of the MEA 11 including the electrolyte membrane 7 and the separators 63 disposed on both sides of the MEA 11 is stacked, a plurality of single cells 3B are collectively bonded. Productivity can be further improved by the increase in the adhesive layer.

  17 and 18, the single cell 3B in FIG. 12 has been described, but the same applies to the single cell 3 in FIGS. 3 and 4 and the single cells 3C, 3D, and 3E in FIGS. Applicable to.

  In particular, for the single cells 3 in FIGS. 3 and 4, separately from the examples in FIGS. 17 and 18, the single cells 3 are manufactured individually one by one, and each of these single cells 3 is batched together. A module body composed of a plurality of single cells 3 may be manufactured by bonding.

  The present invention is not limited to the above-described embodiments, and alternatives that can be easily imagined can be applied to these embodiments without departing from the spirit of the present invention. Needless to say.

1 is a perspective view of a basic fuel cell stack according to the present invention. It is a side view of the fuel cell stack of FIG. It is sectional drawing which shows the structure of the single cell in the fuel cell stack of FIG. It is front sectional drawing which shows an example of the assembly apparatus which manufactures the single cell in this invention. It is a disassembled perspective view which shows the outline of the assembly apparatus of FIG. It is explanatory drawing which shows the compression characteristic of the gas diffusion layer distribute | arranged to both the main surfaces of an electrolyte membrane. It is explanatory drawing which shows the state which provided the predetermined load using the upper surface plate from the lamination | stacking state of the battery component shown in FIG. FIG. 5 is a process diagram illustrating an assembly method using the assembly apparatus of FIG. 4, wherein (a) is a seal material application process diagram, and (b) and (c) are component lamination process diagrams. FIGS. 5A and 5B are process diagrams showing an assembly method using the assembly apparatus of FIG. 4, where FIG. FIGS. 5A and 5B are process diagrams illustrating an assembly method using the assembly apparatus of FIG. 4, wherein FIG. 5A is a seal material curing process diagram, and FIG. It is sectional drawing which shows a part of single cell which shows the 2nd Embodiment of this invention. It is sectional drawing which shows a part of single cell which shows the 3rd Embodiment of this invention. It is a top view which shows another example of a shape of the welding junction part of the separator in the single cell of FIG. It is sectional drawing which shows a part of single cell which shows the 4th Embodiment of this invention. It is sectional drawing containing a part of single cell which shows the 5th Embodiment of this invention. It is sectional drawing containing a part of single cell which shows the 6th Embodiment of this invention. It is a manufacturing process figure which shows the lamination | stacking state before completion when four single cells of FIG. 12 are laminated | stacked and modularized concerning the 7th Embodiment of this invention. It is a manufacturing process figure which shows the lamination | stacking state after completion of FIG.

Explanation of symbols

S Gap 1 Fuel cell stack (fuel cell)
7 Electrolyte membrane (fuel cell components)
11 MEA (fuel cell component)
11a MEA outer peripheral end portion 11b Outer peripheral end protruding portion 15, 63 Separator (fuel cell component)
15a, 63b Separator outer peripheral portion 63a Separator convex portion 63c Projection outer side surface 63d Projection inner side surface 63e Projection flat surface 63f Separator recess 63g Projection outer corner portion 17 Adhesive sealant (seal Material)
19 Cooling water flow path (space between separators)
64 Separator assembly (fuel cell component)
64a Peripheral end of separator assembly 65 Welded part between separators 67 Filler

Claims (13)

A membrane electrode assembly having an electrolyte membrane and gas diffusion layers located on both sides of the electrolyte membrane, and a separator disposed on both sides of the membrane electrode assembly as fuel cell components, and between the fuel cell components In addition, the fuel cell is provided with a sealing material that bonds the fuel cell components to each other and has a sealing function, and the separator protrudes toward the other fuel cell components and the convex portion. And the sealing material is provided at a position corresponding to the convex portion surrounding the concave portion or inside the convex portion surrounding the concave portion, and each fuel cell component surrounds the concave portion. a peripheral edge projecting outwardly from the convex portion, a fuel cell, characterized in that a gap is provided between the outer peripheral end mutual this.   2. The fuel cell according to claim 1, wherein each fuel cell component is polygonal when viewed from the stacking direction, and the gap is provided on each side of the polygon.   Out of the plurality of fuel cell components, the outer peripheral end of at least one fuel cell component protrudes outward from the outer peripheral end of the other fuel cell components, and the at least one fuel cell component has a protrusion. The fuel cell according to claim 1, wherein the fuel cell is provided.   The fuel cell according to claim 3, wherein the fuel cell component provided with the protrusion is the electrolyte membrane.   The outer peripheral end portion of the at least one fuel cell component other than the portion provided with the protruding portion has the same shape as the outer peripheral end of the other fuel cell component as viewed from the stacking direction. The fuel cell according to claim 3 or 4.   The fuel cell according to any one of claims 1 to 5, wherein the separator is formed of a metal plate having an uneven shape, and the two metal plates are overlapped and joined to each other to form a separator joined body. .   The fuel cell according to claim 6, wherein the two separators are bonded and fixed to each other by welding.   The fuel cell according to claim 6 or 7, wherein the outer peripheral end portion of the separator assembly has a structure in which the outer peripheral end portions of the two separators are bonded and fixed to each other.   9. A plurality of spaces are formed between the two separators, and a filler is filled in a position closest to the outer peripheral end portion of the plurality of spaces. A fuel cell according to claim 1. The sealing material is provided at a position corresponding to the convex portion surrounding the concave portion, and the outer side surface of the convex portion provided with the sealing material is disposed on the electrolyte of the convex portion rather than the inner side surface of the convex portion. The fuel cell according to any one of claims 1 to 9, wherein the inclination angle is set to be closer to parallel with a flat surface facing the membrane. The fuel cell according to any one of claims 1 to 9, wherein the sealing material is provided at an outer corner portion of the convex portion at a position corresponding to the convex portion surrounding the concave portion. .   The fuel cell according to claim 11, wherein an outer side surface of the convex portion provided with the sealing material is set at a right angle to a flat surface of the convex portion facing the electrolyte membrane. Wherein the electrolyte membrane, a fuel cell according to any one of claims 1 to 12, characterized in that this has a unit cell having a separator stacked on both sides of the electrolyte membrane stacking a plurality.

Images