JP2007280887A - Cell laminate and fuel cell with it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent force in a direction separating cells from each other from acting even when a cell laminate is bent. <P>SOLUTION: This cell laminate is constrained by constraint members 9 for constraining it in a stacked state; and at least a part of each insulating frame-like member 40 interlaid between separators 20 is projected to the outside from edges 20e of the separators 20 to the extent that it contacts the constraint member 9 before the edges 20e of the separators 20 contact the constraint member 9. It is preferable that a chamfered part within the frame-like member 40 is formed into a rounded shape by cutting the corner parts thereof. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a cell stack and a fuel cell including the same. More specifically, the present invention relates to the structure of members such as a separator and a resin frame that constitute a cell laminate.

In general, a fuel cell (for example, a polymer electrolyte fuel cell) is configured by stacking a plurality of cells each having an electrolyte sandwiched between separators. Conventionally, as such a cell stack of a fuel cell, a cell stack in which a surface perpendicular to a cell stacking direction and a side surface intersect at a right angle is known (for example, see Patent Document 1).
Japanese Patent Laid-Open No. 2003-177876

  However, in the case of the structure as described above, when the cell stack is bent, there is a possibility that a force in a direction in which the cells are separated from each other is brought into contact with the restraining member.

  Accordingly, the present invention provides a cell stack having a structure capable of suppressing the application of force in a direction in which the cells are separated even when the cell stack is bent, and a fuel cell including the same. For the purpose.

  In order to solve this problem, the present inventor has made various studies. The cells stacked as described above can be loaded in the stacking direction by, for example, a pair of left and right tension plates. An insulating film is formed on the inner side surface (the surface facing the cell stack) of such a tension plate by, for example, attaching an insulating tape to prevent leakage or sparking. However, in the case of a fuel cell that employs a metal separator, the corners and edges (so-called metal edges) of the separator formed by punching or the like remain punched. Contact with the insulating film may cause leakage of electricity to the entire stack. In addition, the metal edge of the metal separator is caught on the damaged insulating film, which may cause a gas leak.

  Therefore, the present inventor further examined these problems. In the first place, it is considered that there are mainly three reasons for the contact between the metal separator and the tension plate as described above. That is, the first is that the outer circumference and thickness of the cell stack increase due to cell expansion (thermal expansion) due to heat generation during fuel cell power generation (see FIG. 12). As shown, this includes expansion in the surface direction and expansion in the cell stacking direction. Second, the cell stack can be deformed by the load of the tension plate (see FIG. 13). For example, the tension plate may be deformed when a strong compressive force is applied in the cell stacking direction. Third, there is a variation in the stacking state due to, for example, manual loading during assembly of the cells (see FIG. 14). Cell stacking is performed, for example, while being applied to a jig, but variations are apt to occur when pressing in the stacking direction.

  As described above, the inventor who examined the contact between the metal separator and the tension plate has an idea that leads to the solution of the problem, that is, when the cell stack is bent, the force in the direction of separating the cells acts. It came to the idea that it can be suppressed.

  The present invention is based on such an idea, and is a cell laminate formed by laminating cells in which a membrane-electrode assembly is sandwiched between separators, and the surface of the cells is perpendicular to the laminating direction. The cells having chamfered angles formed with the side surfaces are stacked.

  As described above, since the cell is chamfered on the side portion in the stacking direction, even if the cell stack is bent and comes into contact with the restraining member or the like, surface contact in the conventional manner is not performed. , Contact on a smaller surface or line contact. According to this, since the frictional force (dynamic frictional force) between the side portion of the cell and the restraining member or the like can be reduced, the cells are separated even if the cell stack is bent and comes into contact with the restraining member or the like. It is possible to suppress the force acting in the direction.

  In such a cell laminate, it is preferable that the entire circumference of the cell is chamfered. By chamfering the entire periphery of the cell, it is possible to suppress the force acting in the direction in which the cells are separated from each other even if any part of the periphery of the cell contacts the restraining member or the like.

  The present invention is particularly suitable when applied to a case where a sealing member for fluid sealing provided between the cells seals the fluid by elasticity. A member that physically seals due to elasticity is more susceptible to external forces than a member that chemically seals such as an adhesive. In this respect, in the cell stack as in the present invention, even when the side portion of the cell comes into contact with the restraining member or the like, the force acting in the direction of separating the cells can be suppressed, so that the fluid is sealed by elasticity. In other words, it is possible to reduce the influence by reducing the external force exerted on the physical seal member.

  Further, in the present invention, when at least one of a restraining member for restraining the cell stack in a stacked state and an insulating plate arranged in the vicinity of the stacking direction end of the cell stack is provided, the cell Is chamfered.

  Furthermore, it is preferable that the cell laminated body has a shape in which the chamfered portion is rounded by shaving the fillet by the chamfering. By being rounded and having a so-called R shape, the contact area on the side portion of the cell when it comes into contact with the restraining member or the like is further reduced and comes into contact more smoothly. For this reason, it is possible to further suppress the force acting in the direction of separating the cells.

  Further, in the cell laminate according to the present invention, the chamfered portion is an insulating frame member interposed between the separators. In the case of such a structure, the frame-shaped member can come into contact with the restraining member or the like when the cell stack is bent.

  Here, the present inventor who has repeatedly studied has come to obtain further ideas. That is, as described above, an insulating film is formed on the inner side surface of the tension plate. However, if the edge of the separator comes into contact with this insulating film, there is a risk of electric leakage or gas leakage. In view of such a conventional structure, the present inventor has focused on a structure that can effectively suppress leakage and gas leakage while suppressing the force acting in the direction of separating the cells, and has obtained further ideas. It is a thing.

  The present invention is based on such an idea, and is a cell stack formed by stacking cells formed by sandwiching a membrane-electrode assembly between separators, and restrains the cell stack in a stacked state. In addition to being restrained by the restraining member, at least a part of the insulating frame-like member interposed between the separators contacts the restraining member before the edge of the separator contacts the restraining member. It protrudes outward from the edge of the separator. The separator is, for example, a metal separator.

  For example, metal edges such as corners and edges of a metal separator formed by punching or the like are left in a state of being punched. May cause gas leakage. In this regard, in the cell laminated body according to the present invention, since a part of the frame-shaped member has a structure that protrudes outside the edge, for example, when the cell laminated body is bent, the frame shape A part of the member comes into contact with the restraining member. The frame member is made of, for example, a resin frame, and even if it contacts the restraining member, there is no risk of scratching as in the case of a metal edge. Therefore, it becomes possible to suppress the occurrence of leakage or gas leak.

  In addition, for example, when the metal edge is in contact, the frictional force may be increased by being caught by a restraining member or the like, but in this cell laminate, a part of the frame-like member is in contact. In addition, the frictional force (dynamic frictional force) can be reduced without being caught like a metal edge. For this reason, even if a cell laminated body bends and contacts with a restraining member etc., the force which acts on the direction which leaves | separates between cells can be suppressed.

  In addition, this cell laminate has a simple structure in which a frame-like member such as a resin frame that has been conventionally used is enlarged and protrudes from the edge of the separator. There is no change. Therefore, no major changes are required in the conventional structure or process, which is preferable in terms of cost and the like.

  In the present invention, the restraining member is, for example, a tension plate disposed on a side in the stacking direction of the cell stack. Further, for example, an insulating film is formed on a surface of the tension plate on the cell stack side. When a tension plate with an insulating film formed in this way is used, according to the cell stack according to the present invention, it is possible to avoid the occurrence of electric leakage and spark due to the insulating film being scratched. It becomes.

  Moreover, it is preferable that the chamfered portion of the frame-shaped member has a rounded shape by shaving the fillet. By being rounded and having an R shape, the contact area on the side portion of the cell when it comes into contact with the restraining member or the like is further reduced and comes into contact more smoothly. For this reason, it is possible to further suppress the force acting in the direction of separating the cells.

  Furthermore, the fuel cell according to the present invention includes the cell stack as described above.

  According to the present invention, even when the cell stack is bent, it is possible to suppress the force in the direction in which the cells are separated from each other.

  Hereinafter, the configuration of the present invention will be described in detail based on an example of an embodiment shown in the drawings.

  1 to 10 show an embodiment of a cell stack according to the present invention and a fuel cell including the same. The cell stack (stack) 3 in the present embodiment includes a separator 20 sandwiching the membrane-electrode assembly 30 (in FIG. 1, the two separators constituting the cell 2 are indicated by reference numerals 20a and 20b, respectively). A plurality of sheets or a plurality of sets are stacked. In the present embodiment, the angle formed between the surface perpendicular to the stacking direction and the side surface of each cell 2 is chamfered.

  In the embodiment described below, first, the schematic configuration of the cell 2 constituting the fuel cell 1 will be described, and then the cell stack 3 formed by stacking the cells 2 will be described.

  FIG. 1 shows a schematic configuration of the cell 2 of the fuel cell 1 in the present embodiment. The cells 2 configured as shown in the figure constitute a cell stack (stack) 3 by being sequentially stacked (see FIGS. 2, 7, etc.). The cell stack 3 formed in this way is in a state in which, for example, both ends of the stack are sandwiched between a pair of end plates 8 and a restraining member (for example, a tension plate) 9 is disposed so as to connect the end plates 8 to each other. Thus, the load in the stacking direction is applied and fastened (see FIG. 3).

  The fuel cell 1 including such a cell stack (stack) 3 or the like can be used as an on-vehicle power generation system of a fuel cell vehicle (FCHV), but is not limited thereto. However, it can be used as a power generation system mounted on various mobile bodies (for example, ships, airplanes, etc.), self-propelled devices such as robots, and also as a separator for the stationary fuel cell 1.

  The cell 2 includes an electrolyte, specifically, a membrane-electrode assembly (hereinafter referred to as MEA) 30 and a pair of separators 20 sandwiching the MEA 30 (in FIG. 1, reference numerals 20a and 20b are attached respectively). Etc.) (see FIG. 1). The MEA 30 and the separators 20a and 20b are formed in a substantially rectangular plate shape. Further, the MEA 30 is formed so that its outer shape is smaller than the outer shape of each separator 20a, 20b.

  The MEA 30 includes a polymer electrolyte membrane (hereinafter also simply referred to as an electrolyte membrane) 31 made of a polymer material ion exchange membrane, and a pair of electrodes (an anode side diffusion electrode and a cathode side diffusion electrode) sandwiching the electrolyte membrane 31 from both sides. 32a and 32b (see FIG. 1). The electrolyte membrane 31 is formed larger than the electrodes 32a and 32b. The electrodes 32a and 32b are joined to the electrolyte membrane 31 by, for example, a hot press method while leaving the peripheral edge portion 33.

  The electrodes 32a and 32b constituting the MEA 30 are made of, for example, a porous carbon material (diffusion layer) carrying a catalyst such as platinum attached to the surface thereof. One electrode (anode) 32a is supplied with hydrogen gas as a fuel gas (reactive gas), and the other electrode (cathode) 32b is supplied with an oxidizing gas (reactive gas) such as air or an oxidant. An electrochemical reaction is generated in the MEA 30 by the gas, and the electromotive force of the cell 2 is obtained.

  The separator 20 (20a, 20b) is made of a gas impermeable conductive material. Examples of the conductive material include carbon and a hard resin having conductivity, and metals such as aluminum and stainless steel. The base material of the separator 20 (20a, 20b) of the present embodiment is formed of a plate-like metal (metal separator), and a film having excellent corrosion resistance is formed on the surface of the base material on the electrodes 32a, 32b side. (For example, a film formed by gold plating) is formed.

  Further, a groove-like flow path constituted by a plurality of concave portions is formed on both surfaces of the separators 20a and 20b. These flow paths can be formed by press molding in the case of the separators 20a and 20b of the present embodiment in which the base material is formed of, for example, a plate-like metal. The groove-shaped flow path formed in this way constitutes an oxidizing gas flow path 34, a hydrogen gas flow path 35, or a cooling water flow path 36. More specifically, a plurality of gas passages 35 for hydrogen gas are formed on the inner surface on the electrode 32a side of the separator 20a, and a plurality of cooling water passages 36 are formed on the back surface (outer surface). (See FIG. 1). Similarly, a plurality of gas channels 34 for oxidizing gas are formed on the inner surface of the separator 20b on the electrode 32b side, and a plurality of cooling water channels 36 are formed on the back surface (outer surface) (FIG. 1). reference). For example, in the case of this embodiment, the gas flow path 34 and the gas flow path 35 in the cell 2 are formed to be parallel to each other. Further, in the present embodiment, regarding the two adjacent cells 2 and 2, when the outer surface of the separator 20a of one cell 2 and the outer surface of the separator 20b of the cell 2 adjacent thereto are attached together, The water channel 36 is integrated to form a channel having a rectangular or honeycomb cross section (see FIG. 1).

  Furthermore, as described above, the separators 20a and 20b have a relationship in which at least the uneven shape for forming a fluid flow path is reversed between the front surface and the back surface. More specifically, in the separator 20a, the back surface of the convex shape (convex rib) forming the hydrogen gas gas flow path 35 is a concave shape (concave groove) forming the cooling water flow path 36, and the gas flow path The back surface of the concave shape (concave groove) forming 35 is a convex shape (convex rib) forming the cooling water channel 36. Furthermore, in the separator 20b, the back surface of the convex shape (convex rib) that forms the gas flow path 34 of the oxidizing gas has a concave shape (concave groove) that forms the cooling water flow path 36, and the concave that forms the gas flow path 34. The back surface of the shape (concave groove) is a convex shape (convex rib) forming the cooling water flow path 36.

  Further, in the vicinity of the longitudinal ends of the separators 20a and 20b (in the case of this embodiment, in the vicinity of one end shown on the left side in FIG. 1), the manifold 15a on the inlet side of the oxidizing gas, hydrogen gas An outlet side manifold 16b and a cooling water outlet side manifold 17b are formed. For example, in the case of this embodiment, these manifolds 15a, 16b, and 17b are formed by substantially rectangular or trapezoidal through holes provided in the separators 20a and 20b (see FIG. 1). Further, an oxidant gas outlet side manifold 15b, a hydrogen gas inlet side manifold 16a, and a cooling water inlet side manifold 17a are formed at opposite ends of the separators 20a and 20b. In the case of this embodiment, these manifolds 15b, 16a, and 17a are also formed by substantially rectangular or trapezoidal through holes (see FIG. 1). In FIG. 3, FIG. 4, etc., the signs of the manifolds are shown in a form in which the suffixes a and b are omitted.

  Among the manifolds as described above, the inlet side manifold 16a and the outlet side manifold 16b for the hydrogen gas in the separator 20a are connected to the inlet side communication passage 61 and the outlet side communication passage 62 formed in the separator 20a in a groove shape. Each communicates with a gas flow path 35 of hydrogen gas. Similarly, the inlet side manifold 15a and the outlet side manifold 15b for the oxidizing gas in the separator 20b are oxidized via the inlet side communication passage 63 and the outlet side communication passage 64 formed in the separator 20b in a groove shape. The gas communicates with the gas flow path 34 (see FIG. 1). Further, the inlet side manifold 17a and the outlet side manifold 17b of the cooling water in each separator 20a, 20b are connected to each separator 20a, 20b through an inlet side communication passage 65 and an outlet side communication passage 66 formed in a groove shape. Each communicates with the cooling water passage 36. With the configuration of the separators 20a and 20b as described above, the cell 2 is supplied with oxidizing gas, hydrogen gas, and cooling water. As a specific example, when the cells 2 are stacked, for example, hydrogen gas passes from the inlet side manifold 16a of the separator 20a through the communication passage 61 and flows into the gas flow path 35, and is supplied to the power generation of the MEA 30. After that, the fluid passes through the communication passage 62 and flows out to the outlet side manifold 16b.

  The first seal member 13a and the second seal member 13b are both formed of a plurality of members (for example, four small rectangular frames and a large frame for forming a fluid flow path) (FIG. 1). Among these, the first seal member 13a is provided between the MEA 30 and the separator 20a. More specifically, a part of the first seal member 13a is a peripheral portion 33 of the electrolyte membrane 31 and a gas flow path 35 of the separator 20a. It is provided so that it may interpose between the surrounding parts. The second seal member 13b is provided between the MEA 30 and the separator 20b. More specifically, a part of the second seal member 13b is a peripheral portion 33 of the electrolyte membrane 31 and the gas channel 34 of the separator 20b. It is provided so as to be interposed between the surrounding portions.

  Furthermore, a plurality of members (for example, four small rectangular frames and a large frame for forming a fluid flow path) are formed between the separators 20b and 20a of the adjacent cells 2 and 2. A third seal member 13c is provided (see FIG. 1). The third seal member 13c is provided so as to be interposed between a portion around the cooling water passage 36 in the separator 20b and a portion around the cooling water passage 36 in the separator 20a, and seals between them. It is.

  In addition, as the first to third seal members 13a to 13c, an elastic body (gasket) that seals a fluid by physical contact with an adjacent member, or an adhesive that is bonded by chemical bonding with an adjacent member. An agent or the like can be used. For example, in this embodiment, a member that is physically sealed by elasticity is employed as each of the seal members 13a to 13c (see FIG. 8 and the like). Instead, a member that is sealed by a chemical bond such as the above-described adhesive is used. It can also be adopted.

  The frame-like member 40 (indicated by reference numerals 40a and 40b in FIG. 1) is a member made of, for example, resin (hereinafter also referred to as a resin frame) sandwiched between the separators 20a and 20b together with the MEA 30. For example, in the present embodiment, a thin frame-shaped resin frame 40 (40a, 40b) is interposed between the separators 20a, 20b, and at least a part of the MEA 30 such as a portion along the peripheral edge 33 is defined as the front side by the resin frame 40. It is made to clamp from the back side (refer FIG. 6 etc.). The resin frame 40 provided in this way functions as a spacer between the separators 20 (20a, 20b) that supports the fastening force, functions as an insulating member, and as a reinforcing member that reinforces the rigidity of the separator 20 (20a, 20b). Demonstrate the function.

  Next, the configuration of the fuel cell 1 will be briefly described (see FIGS. 2 and 3). The fuel cell 1 in the present embodiment includes a cell stack (stack) 3 in which a plurality of single cells 2 are stacked, and the output terminals 5 are sequentially placed outside the single cells 2 and 2 located at both ends of the cell stack 3. The attached current collector plate 6, insulating plate 7 and end plate 8 are arranged (see FIG. 2). The cell stack 3 is constrained in a stacked state by a constraining member (hereinafter also referred to as a tension plate) 9. The tension plate 9 is provided so as to bridge between both the end plates 8 and 8 and is disposed, for example, so that a pair is opposed to both sides of the cell stack 3 (see FIG. 7 and the like). The tension plate 9 is fixed to the end plates 8 and 8 with bolts or the like, and maintains a state in which a predetermined fastening force (compression force) is applied in the stacking direction of the single cells 2.

  Furthermore, an insulating film 9a is formed on the inner side surface (the surface facing the cell stack 3) of the tension plate 9 to prevent leakage or sparks (see FIG. 8 and the like). Specifically, the insulating film 9a is formed by, for example, an insulating tape attached to the inner surface of the tension plate 9, or a resin coating applied so as to cover the surface.

  An example of a member (elastic module) that applies a fastening force (compression force) to the cell laminate 3 is as follows. That is, an elastic body 11 such as a coil spring disposed in parallel with each other and a pair of plate-like members 12 that sandwich the plurality of elastic bodies 11 in the stacking direction are disposed at one end of the cell stack 3. (See FIG. 7). Further, a connecting member 13 is interposed between the plate-like member 12 and the end plate 8, and a structure capable of swinging is realized by a configuration in which the connecting member 13 itself contacts in a flexible or pivot shape. (See FIG. 7). As a result of stacking a large number of cells 2 (for example, about 200 to 400), even if the cell stack 3 is distorted due to lateral deviation such as a trapezoidal shape, such a support structure is used. For example, by swinging the head around the connection member 13, it is possible to correct the distortion by appropriately changing the angle corresponding to the deviation. Furthermore, it is also preferable that the connection member 13 includes a screw portion. According to the connecting member 13 with the threaded portion, it is possible to change the interval between the plate-like member 12 and the end plate 8 by rotating at the position, and therefore, when the cells are stacked, the stacking thickness varies from one solid to another. Even in the case of the occurrence of the problem, the overall thickness (total length) of the cell stack 3 can be finely adjusted by changing the axial length by relatively rotating the connecting member 13 with the threaded portion. For this reason, it is easy to finely adjust the fastening force acting on the cell stack 3. As the connection member 13 with the screw part as described above, a screw called “potato screw” or the like (for example, a set screw with a slot) can be used.

  Next, the characteristic structure of the cell stack 3 according to the present invention, more specifically, the structure of the separator 20 and the resin frame (frame member) 40, particularly the peripheral portion will be described. As described above, the cell laminate 3 has a structure in which the cells 2 having chamfered angles formed by the surface and the side surface perpendicular to the stacking direction are stacked, and the restraint member (tension plate) 9 It is in a state of being restrained in a stacked state (see FIG. 8 and the like).

  For example, in this embodiment, at least a part of the insulating resin frame 40 interposed between the separators 20 (20a, 20b) is formed by the edge of the separator 20 (indicated by reference numeral 20e in FIG. 8) as a restraining member (tension). (Plate) 9 has a structure that protrudes outward from the edge 20e of the separator 20 to the extent that it contacts the restraining member 9 before it contacts the plate 9 (see FIG. 8 and the like). As described above, the insulating film 9a is formed on the inner side surface of the restraining member 9 (see FIG. 8). When the edge 20e of the separator (for example, a metal separator) 20 comes into contact with the insulating film 9a, electric leakage or gas leakage occurs. There is a fear. In contrast, according to the cell laminate 3 of the present embodiment as described above, the resin frame 40 contacts the insulating film 9a before the edge 20e of the separator 20, and the edge 20e contacts the insulating film 9a. It functions so as not to touch.

  Further, the protruding edge portion of the resin frame 40 is in a state where the angle formed between the surface perpendicular to the cell stacking direction and the side surface is chamfered. The chamfering referred to here is to add a slope or roundness to the corner of the intersection between the faces. For example, in this embodiment, the fillet of the edge is shaved and rounded (FIG. 6). , See FIG. When the edge of the resin frame 40 is rounded to have an R shape in this way, the contact area when contacting the restraining member (tension plate) 9 is small and smooth, and the frictional force ( (Dynamic friction force) can be reduced. Therefore, even if the cell stack 3 is bent and a part thereof contacts the restraining member 9, it is possible to suppress the force acting between the cells so that the cells 2 are separated from each other.

  Moreover, according to the resin frame 40 having such an end face shape, there is no risk that the restraining member (tension plate) 9 itself or the insulating film 9a formed on the surface thereof will be damaged even if the peripheral edge contacts. . Therefore, it is possible to suppress the occurrence of electric leakage or gas leak.

  In addition, the cell stack 3 in the present embodiment has a simple structure in which a conventionally used frame-like member (for example, the resin frame 40 in the present embodiment) is enlarged to protrude from the edge 20e of the separator 20. It is. Also, there is no significant change in the process of lamination and the like. Therefore, it is not necessary to make a major change to the conventional structure or process, which is preferable in terms of cost.

  In the present embodiment, the case where the insulating film 9a is formed on the entire one surface of the restraining member 9 (the surface facing the cell stack 3) has been described. However, the insulating film 9a is not partially formed. The cell stack 3 of the present embodiment is also applicable. For example, when there is a portion that is not formed as prescribed in the insulating film 9a and a part of the restraining member 9 is exposed (see FIG. 10), the cell 2 is separated in the conventional structure. However, according to the cell laminate 3 of the present embodiment, these can be effectively suppressed. That is, the peripheral edge of the resin frame 40 can be smoothly slidably contacted on the exposed surface of the restraining member 9 to prevent the force in the direction of separating the cells 2 from acting, and the protruding resin The frame 40 is electrically insulated by separating the restraining member 9 and the edge 20a of the separator 20 by a certain distance or more.

  Further, according to the present embodiment, a desired effect can be obtained even when the cell stack 3 is tilted by receiving a larger external force or the like. That is, even if the plurality of cells are inclined by, for example, θ degrees due to the influence of an external force or the like, it is the peripheral portion of the resin frame 40 that contacts the restraining member 9 or the insulating film 9a formed on the surface thereof. It is possible to avoid the edge 20e of the separator 20 from coming into contact with the restraining member 9 or the insulating film 9a (see FIG. 9).

  In addition, in chamfering the periphery of the resin frame 40, it is preferable that the chamfering is performed over the entire circumference of the cell 2 (or the resin frame 40 constituting the cell 2). In this way, by chamfering the entire circumference of the cell 2, any part of the peripheral edge of the cell 2 (in this embodiment, any part of the peripheral edge of the resin frame 40) contacts the restraining member 9. Even if it does, it can suppress that the force of the direction which leaves | separates between cells 2 acts, and can suppress that electric leakage and gas leak arise.

  In the cell stack 3 as described above, for example, the thermal expansion of the cell 2 due to heat generation during power generation of the fuel cell 1 (see FIG. 12), the influence of the load of the restraining member (tension plate) 9 (see FIG. 13), the assembly For example, when the cell stack 3 is bent due to a variation (see FIG. 14) that may occur due to, for example, manual loading during the attaching operation, the end of the resin frame 40 is not the edge 20e of the separator 20 The structure is in contact with the restraining member 9. In addition, in this case, the resin frame 40 can be in sliding contact with the restraining member 9 (or the insulating film 9a on the surface) smoothly and with a small frictional force. According to such a cell laminate 3 of the present embodiment, even when the cell laminate 3 is bent, it is possible to suppress a force acting in a direction in which the cells 2 are separated from each other, and to prevent electric leakage and gas leak. It can be suppressed from occurring.

  The cell laminate 3 as described above is particularly suitable when the fluid sealing seal member provided between the cells 2 seals the fluid by elasticity. A member that physically seals due to elasticity is more susceptible to external forces than a member that chemically seals such as an adhesive. In this respect, in the cell laminate 3 as described above, when the peripheral portion of the resin frame 40 comes into contact with the restraining member 9, the force acting in the direction in which the cells 2 are separated can be suppressed. In other words, the external force exerted on the physical seal member can be reduced to reduce the influence. For example, in the case of the present embodiment, the above-described third seal member 13c is made of, for example, rubber and is a gasket that seals fluid (cooling water) by elasticity, and reduces the external force exerted on the third seal member to reduce the influence. It is possible to do. In addition, although the case where the 3rd seal member 13c was a physical seal (gasket) was illustrated here, this is only an example. Even when the sealing member is a member that is sealed by chemical bonding, such as an adhesive, the structure according to the present embodiment can be applied.

  The above-described embodiment is an example of a preferred embodiment of the present invention, but is not limited thereto, and various modifications can be made without departing from the scope of the present invention. For example, in the present embodiment, a rounded surface is illustrated as an example of chamfering on the resin frame 40 (see FIG. 8 and the like). In addition to rounding the corner of the intersection between the surface in this way, It is also possible to attach a slope. For example, although not shown in detail, the width of the chamfer can be made slightly (see FIG. 10).

  Moreover, in embodiment mentioned above, both the restraint member 9 for restraining the cell laminated body 3 in a lamination | stacking state, and the insulating board 7 arrange | positioned in the stacking direction edge part vicinity of the said cell laminated body 3 are provided. Although the case where it applied to the fuel cell 1 was illustrated, object is not restricted to this. For example, even when only one of the restraining member 9 and the insulating plate 7 is provided, it is possible to apply the present invention by chamfering a part of the cell 2 (periphery of the resin frame 40).

  Furthermore, in the present embodiment, the case where the periphery of the resin frame 40 is chamfered as a part of the cell 2 has been described, but this is also only a preferred example. As another example, there may be mentioned a case where a cell monitor (not shown) for detecting a cell voltage is provided on a protrusion protruding in the in-plane direction at the periphery of the separator 20. In this case, it is possible to make the cell monitor or the protruding convex portion function in the same manner as the resin frame 40 provided so as to protrude from the present embodiment.

  In the present embodiment, a certain amount of clearance is provided between the restraining member 9 or the insulating film 9a formed on the surface thereof and the resin frame 40 (see FIG. 8 and the like), but this clearance is eliminated. In other words, it is possible to make the peripheral edge of the resin frame 40 abut on the restraining member 9 or the insulating film 9a in a normal state (see FIG. 11). In this case, if the amount of protrusion of the resin frame 40 is increased, the restraining member 9 (or the insulating film 9a) and the edge 20e of the separator 20 can be separated from each other, so that further insulation can be ensured. It becomes like this. In this case, the cells 2 can be stacked on the restraining member (tension plate) 9 in order to eliminate the variation between the cells 2 that may occur at the time of stacking. However, in consideration of deformation due to thermal expansion, it is preferable that only one side be in contact with both, and a clearance is provided on the opposite side as in the above-described embodiment (see FIG. 11).

It is a disassembled perspective view which shows the structural example of the cell in this embodiment. It is a perspective view which shows the structural example of a cell laminated body. It is a perspective view which shows another structural example of a cell laminated body. It is a figure which decomposes | disassembles and shows the structure of the cell which comprises a cell laminated body. It is a top view which shows the structural example of the cell in this embodiment. It is sectional drawing of the cell in the VI-VI line in FIG. It is a figure which shows the structural example of the cell laminated body in which the elastic module for making a fastening force (compression force) act was attached. It is an enlarged view which shows the structure of the circled part in FIG. 7 in detail. It is a figure which shows a mode when a some cell inclines because a cell laminated body receives a still larger external force. It is a figure which shows an example of a structure when a part of restraint member 9 is exposed and the width | variety of chamfering was made small. It is a figure which shows other embodiment of this invention, (A) The structural example at the time of making the periphery of a resin frame contact | abut to a restraining member or an insulating film, and (B) The enlarged view of the said part. It is the schematic showing the 1st reason that a metal separator and a tension plate contact briefly. It is the schematic showing the 2nd reason that a metal separator and a tension plate contact briefly. It is the schematic showing the 3rd reason that a metal separator and a tension plate contact, and (A) is a cell laminated body which produced variation, and (B) is a metal separator and tension plate in the cell laminated body. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Fuel cell, 2 ... Cell, 3 ... Stack (cell laminated body), 7 ... Insulating plate, 9 ... Tension plate (restraint member), 9a ... Insulating film, 13c ... 3rd seal member (seal member for fluid seals) ), 20 (20a, 20b) ... Separator, 20a ... Edge of separator, 30 ... MEA (membrane-electrode assembly), 40 ... Resin frame (frame-like member)

Claims (12)

A cell laminate constituted by laminating cells formed by sandwiching a membrane-electrode assembly with a separator,
A cell laminate, wherein the cells are chamfered at an angle formed by a surface and a side surface perpendicular to the stacking direction of the cells.   The cell laminate according to claim 1, wherein the entire circumference of the cell is chamfered.   The cell stack according to claim 1 or 2, wherein a sealing member for fluid sealing provided between the cells seals the fluid by elasticity.   The cell is chamfered when at least one of a restraining member for restraining the cell stack in a stacked state and an insulating plate arranged near the stacking direction end of the cell stack is provided. The cell laminate according to any one of claims 1 to 3, wherein:   The cell stack according to any one of claims 1 to 4, wherein the chamfered portion has a rounded shape by shaving the fillet by the chamfering.   6. The cell laminate according to claim 1, wherein the chamfered portion is an insulating frame member interposed between the separators. A cell laminate constituted by laminating cells formed by sandwiching a membrane-electrode assembly with a separator,
While being restrained by a restraining member for restraining the cell laminate in a laminated state,
At least a part of the insulating frame member interposed between the separators protrudes outward from the edge of the separator to the extent that the edge of the separator contacts the restraining member before contacting the restraining member. A cell laminate characterized by comprising:   The cell laminate according to claim 7, wherein the separator is a metal separator.   The cell stack according to claim 7 or 8, wherein the restraining member is a tension plate disposed on a side portion in the stacking direction of the cell stack.   The cell stack according to claim 9, wherein an insulating film is formed on a surface of the tension plate on the cell stack side.   The cell laminate according to any one of claims 7 to 10, wherein a chamfered portion of the frame-shaped member has a rounded shape by shaving the fillet.   A fuel cell comprising the cell stack according to any one of claims 1 to 11.

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