JP2008130479A - Unit cell for fuel battery and fuel battery provided with the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a unit cell for a fuel battery which can improve rigidness of a manifold portion and prevent occurrence of warp, and provide a fuel battery equipped with the above. <P>SOLUTION: The unit cell 25 for a fuel battery is provided with an electrolyte-electrode assembly in which an anode electrode is arranged on one side surface of the electrolyte and a cathode electrode is arranged on the other side surface, frame members 21, 22 arranged on both sides of the electrolyte-electrode assembly and separators 23, 24 arranged on an opposite side to a surface where the frame members 21, 22 face the electrolyte-electrode assembly. The frame members 21, 22 are composed of a base material part made by a base material and a high rigidity part made by a material having a higher rigidity than the base material. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an improvement in a single cell for a fuel cell and a fuel cell including the same.

  Conventionally, as a general fuel cell, for example, a membrane-electrode assembly having an electrolyte membrane, an anode electrode disposed on one surface of the electrolyte membrane, and a cathode electrode disposed on the other surface ( A cell stack comprising a single cell having a structure in which separators are disposed on both sides of an MEA (Membrane Electrode Assembly, hereinafter simply referred to as “MEA”) via a frame-shaped member, and the single cells are stacked. A stack is formed by arranging terminals, insulators, pressure plates, end plates and the like at both ends of the single cell in the stacking direction, and the stack is fastened and fixed in the cell stacking direction. (For example, refer to Patent Document 1).

  In the separator used in such a fuel cell, a gas flow path is usually formed in a region corresponding to the power generation unit of the MEA, and manifold portions are formed on both sides thereof. For this reason, the region corresponding to the power generation unit of the MEA has a higher bending rigidity because the second moment is increased due to the presence of the gas flow path, but the region where the manifold portion is formed is the region where the manifold portion is formed. Compared with the region corresponding to, the unevenness (embossed) shape is less and the manifold is opened, so that the bending rigidity is lowered and the warp is likely to occur.

  In a fuel cell, for example, if the stack temperature suddenly rises due to rapid warm-up of the vehicle or the like, the stack length may be increased. However, if ice is formed in the manifold, this portion is restrained by the ice. , The stack length is suppressed from increasing. For this reason, if the rigidity is low, cracks are likely to occur at the interface between the portion where the ice is formed and the portion where the ice is not formed, and if there is a crack, gas may leak from here. Here, particularly in the case of a metal separator, the thermal conductivity in the cell surface direction is low. For example, when the cooling water is heated up due to rapid warm-up operation from below freezing point, the temperature of the manifold part is unlikely to rise. The in-plane temperature difference becomes large and the ice formed in the manifold is difficult to melt. Therefore, it is necessary to improve the rigidity of the manifold part.

  In addition, in order to make the distance between a pair of frames arranged on both sides of the MEA constant, a fuel cell unit cell in which a large number of spacers are arranged on the frame has been introduced. In this single cell, the interval between the frames is made constant, so that the single cell has rigidity capable of withstanding the pressing load acting on the battery module. (For example, refer to Patent Document 2).

  In addition, a polymer electrolyte fuel cell in which a separator is formed by a separator substrate in which a flow path and a manifold are formed and two frames is also introduced. In this polymer electrolyte fuel cell, the gas sealability is improved by using a frame having a three-layer structure in which a resin layer is sandwiched between rubber layers. (For example, refer to Patent Document 3).

In addition, in the separator, the region corresponding to the power generation part of the MEA is set as a conductive region, and the region other than the conductive region is set as an insulating resin region, thereby improving the in-plane uniformity of the contact point between the separator and the electrode. In addition, a fuel cell separator that can obtain a high voltage even when output at a high current density has been introduced. In this fuel cell separator, the strength and dimensional stability of the separator are improved by forming the insulating resin region from a resin composition obtained by adding a filler to an insulating resin. (For example, refer to Patent Document 4).
JP 2006-19204 A Japanese Patent Laid-Open No. 2004-6419 JP 2004-165043 A JP 2002-358882 A

  However, in the unit cell of the fuel cell described in Patent Document 2 described above, a large number of spacers are disposed on the frame, but this spacer provides an interval between a pair of frames disposed on both sides of the MEA. By keeping constant, it is arranged to give rigidity enough to withstand the pressure load acting on the battery module, and it suppresses the area where the stack length increases as the stack temperature rises and the stack length increases It does not improve the rigidity of the manifold part in order to suppress the occurrence of cracks at the interface with the region to be formed, and such an idea is not disclosed.

  In addition, the polymer electrolyte fuel cell described in Patent Document 3 uses a frame having a three-layer structure in which a resin layer is sandwiched between rubber layers, and the rubber layer constitutes a gasket and is stacked. However, the rigidity of the manifold portion is not improved in order to suppress the occurrence of cracks at the interface between the region in which the stack length increases with the temperature rise and the region in which the stack length is suppressed from increasing. Moreover, such an idea is not disclosed.

  In addition, the fuel cell separator described in Patent Document 4 has a region corresponding to the power generation part of the MEA as a conductive region, and a region other than the conductive region as an insulating resin region, on both sides of the MEA. The structure in which the separator is disposed via the frame member is not provided.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a single cell for a fuel cell that can improve the rigidity of a manifold portion and suppress warping, and a fuel cell including the same. And

  In order to achieve this object, the present invention provides an electrolyte-electrode assembly in which an anode electrode is disposed on one surface of an electrolyte and a cathode electrode is disposed on the other surface, and on both sides of the electrolyte-electrode assembly. A single cell for a fuel cell comprising: a frame member disposed; and a separator disposed on a surface of each frame member opposite to the surface facing the electrolyte-electrode assembly. The frame-shaped member provides a single cell for a fuel cell including a base portion formed of a base material and a high-rigidity portion formed of a material having higher rigidity than the base material. To do.

  The fuel cell single cell having this configuration includes a base member in which the frame-like member is formed of a base material, and a high-rigidity part formed of a material having higher rigidity than the base material. Therefore, the rigidity can be improved as compared with the conventional frame-shaped member formed only of the base material. Here, since each said separator is each arrange | positioned at the said frame-shaped member, when the rigidity of a frame-shaped member improves, the said separator will be reinforced and the rigidity of a single cell will be improved. be able to.

  The high-rigidity part may have a substantially plate-like member, and in this case, the substantially plate-like member can contain a metal. The substantially plate-like member may be a metal layer. This substantially plate-shaped member may be laminated | stacked on the layer which consists of the said base material, and may be arrange | positioned between the layers which consist of a base material.

  The high-rigidity part may include a fibrous filler. In this case, the high-rigidity part may be composed of a fibrous filler, or may be composed of a layer including the fibrous filler and the above-described substantially plate-like member. The fibrous filler may be included in the substantially plate-like member.

  The high-rigidity part may contain a spherical filler. In this case, the high-rigidity part may be composed of a spherical filler, or may be composed of a layer including the spherical filler and the above-described substantially plate-like member. This spherical filler may be contained in the substantially plate-shaped member. The high-rigidity part may be composed of a layer containing the spherical filler, a layer containing a fibrous filler, and a substantially plate-like member.

  The fuel cell unit cell according to the present invention may have a configuration in which a manifold is formed on the frame-shaped member and the high-rigidity portion is formed on an outer peripheral portion of the manifold.

  In addition, the material having higher rigidity than the base material may include a material having higher thermal conductivity than the base material. In this way, in addition to the above advantages, for example, when the temperature of the cooling water rises due to rapid warm-up operation from below freezing point or the like, the temperature of the manifold part is likely to rise. Can be relaxed. In addition, when the material whose rigidity is higher than the said base material consists of multiple types of materials, at least 1 type of thermal conductivity should just be higher than the thermal conductivity of the said base material among these multiple types of materials.

  Moreover, this invention provides the fuel cell provided with the single cell for fuel cells concerning this invention mentioned above. Since the fuel cell with this configuration has improved rigidity of the single cell, not only in a normal state, for example, even when the temperature of the stack suddenly rises due to rapid warm-up operation, The single cell can be prevented from warping.

  The fuel cell single cell according to the present invention can improve the rigidity of the single cell itself by improving the rigidity of the frame-like member. Even when the temperature of the stack suddenly rises due to operation or the like, the single cell can be prevented from warping, and a single cell for a fuel cell with high performance and high reliability can be provided.

  In the fuel cell according to the present invention, the rigidity of the single cell is improved. For example, even when the temperature of the stack suddenly increases due to rapid warm-up operation or the like, the single cell can be prevented from warping. . As a result, a high-performance and highly reliable fuel cell can be provided.

  Next, a single cell for a fuel cell according to a preferred embodiment of the present invention and a fuel cell including the single cell will be described in detail with reference to the drawings. In addition, embodiment described below is the illustration for demonstrating this invention, and this invention is not limited only to these embodiment. Therefore, the present invention can be implemented in various forms without departing from the gist thereof.

  FIG. 1 is an exploded perspective view of a fuel cell unit cell according to an embodiment of the present invention, FIG. 2 is a plan view of a frame-like member that is a component of the fuel cell unit cell shown in FIG. 1, and FIG. FIG. 4 is an enlarged cross-sectional view taken along line III-III shown in FIG. 2, FIG. 4 is a cross-sectional view showing a part of a unit cell for a fuel cell according to an embodiment of the present invention, and FIG. It is the whole schematic figure in the posture which made the cell lamination direction of the fuel cell provided with the single cell for fuel cells concerning form to the up-and-down direction. In each of the drawings, the thickness, size, enlargement / reduction ratio, etc. of each member are not shown in line with actual ones for easy understanding.

  The fuel cell described in the present embodiment is a solid polymer electrolyte fuel cell, and can be mounted on, for example, a fuel cell vehicle, but may be used other than the vehicle.

  As shown in FIGS. 1 to 5, the single cell 25 according to the present embodiment includes an MEA (membrane-electrode assembly) 10, a frame-shaped member 21 disposed on one surface of the MEA 10, and the other of the MEA 10. A frame-shaped member 22 disposed on the surface of the frame-like member, a separator 23 disposed on the surface of the frame-shaped member 21 opposite to the side where the MEA 10 is disposed, and the MEA 10 of the frame-shaped member 22 disposed. And a separator 24 disposed on a surface opposite to the side on which it is formed.

  The MEA 10 is disposed on one surface of the electrolyte membrane 11 made of an ion exchange membrane, the electrolyte membrane 11, an anode electrode (fuel electrode) 14 made up of the catalyst layer 12 and the diffusion layer 13, and the other of the electrolyte membrane 11. The cathode electrode (oxidant electrode) 17 including the catalyst layer 15 and the diffusion layer 16 is provided on the surface.

The frame-shaped member 21 is disposed on the anode electrode 14 side of the MEA 10, and the frame-shaped member 22 is disposed on the cathode electrode 17 side of the MEA 10. The frame-like members 21 and 22 are hollowed out so that the power generation part of the MEA 10 is exposed to the separators 23 and 24, and manifold parts 40A and 40B are formed on both sides thereof. The manifold section 40A is provided with an inlet side cooling water manifold 41 _IN , an outlet side fuel gas manifold 42 _OUT , and an inlet side air manifold 43 _IN . On the other hand, the manifold section 40B is provided with an outlet side cooling water manifold 41 _OUT , an inlet side fuel gas manifold 42 _IN , and an outlet side air manifold 43 _OUT . The frame-shaped members 21 and 22 are formed with gas flow passage communication portions 47 that communicate the manifold portions 40A and 40B with the gas flow passage portions 53 and 54 formed in the separators 23 and 24, respectively.

  In addition, as shown in FIGS. 3 and 4, the frame-shaped members 21 and 22 include manifold parts 40A and 40B, a first base part 101, a high-rigidity member 102, and a second base part. 103 is arranged in order. That is, the frame-shaped members 21 and 22 have a configuration in which the high-rigidity member 102 is inserted between the first base material portion 101 and the second base material portion 103. In the present embodiment, the high rigidity member 102 forms a high rigidity portion.

  The first base material portion 101 and the second base material portion 103 are formed from a resin that is a base material, and the high-rigidity member 102 includes the first base material portion 101 and the second base material portion 103 (that is, It is made of a material (for example, metal) having higher rigidity than the base material. For example, the frame-shaped members 21 and 22 insert resin around a substantially plate-like high-rigidity member 102 formed of a material having higher rigidity than the first base material portion 101 and the second base material portion 103. It can be obtained by molding. Thus, the frame-shaped members 21 and 22 are more rigid than the first base material portion 101 and the second base material portion 103 formed of the base material (resin in the present embodiment) and the base material. Since it is configured to include the high-rigidity member 102 formed of a high material (metal in the present embodiment), the rigidity can be improved compared to a conventional frame-shaped member formed of only the base material. Can do.

  Here, separators 23 and 24, which will be described later, have a fuel gas flow path 53A formed on one surface of a region corresponding to the hollowed portion (the power generation unit of MEA 10) of frame-shaped members 21 and 22, and the other surface. Since the oxidizing gas flow channel 54A is formed in this area, the second moment of section in this region is increased, and the rigidity for increasing the bending rigidity is relatively high. On the other hand, the regions where the manifold portions of the separators 23 and 24 are formed have less unevenness (embossed) than the regions where the fuel gas channel 53A and the oxidizing gas channel 54A are formed, and each manifold is opened. Therefore, the bending rigidity becomes low and the warp tends to occur. Therefore, in the present embodiment, the high-rigidity member 102 is disposed in the manifold portions 40A and 40B of the frame-like members 21 and 22, which are regions where the rigidity of the separators 23 and 24 is low, and the rigidity of the single cell 25 is in-plane. The balance is improved so that it is uniform. That is, the rigidity of the single cell 25 is made uniform in the plane by supporting the regions where the rigidity of the separators 23 and 24 is low in the region where the rigidity of the frame-like members 21 and 22 is high.

The separators 23 and 24 are impermeable, and can be composed of, for example, a stainless plate plated with a conductive metal (for example, nickel plating). These separators 23 and 24 constitute a conductive path between adjacent cells. A gas flow channel portion 53 in which a fuel gas flow channel 53A is formed is formed on the surface of the separator 23 facing the MEA 10 (the surface facing the MEA 10 side). A cooling water passage 55 is formed on the surface of the separator 23 opposite to the surface on which the gas passage portion 53 is formed. Further, a gas flow channel portion 54 in which an oxidizing gas flow channel 54A is formed is formed on the surface of the separator 24 that faces the MEA 10, and is opposite to the surface on which the gas flow channel portion 54 of the separator 24 is formed. A cooling water channel 56 is formed on the surface. The separators 23 and 24 also have the aforementioned inlet-side cooling water manifold 41 _IN , outlet-side fuel gas manifold 42 _OUT , inlet-side air manifold 43 _IN , outlet-side cooling water manifold 41 _OUT , and inlet-side fuel gas. A manifold 42 _IN and an outlet air manifold 43 _OUT are formed.

  The fuel gas channel 53A and the oxidizing gas channel 54A correspond to each other with the MEA 10 interposed therebetween. Further, the cooling water channel 55 formed in the separator 23 and the cooling water channel 56 formed in the separator 24 communicate with each other without being separated in the cell stacking direction.

  The frame-shaped member 21 and the separator 23, and the frame-shaped member 22 and the separator 24 may be bonded and fixed with a sealing adhesive, and the frame-shaped member 21 (22) and the separator 23 (24) are injection-molded. For example, fixing (welding) may be performed without providing a separate adhesive. Further, the frame-shaped member 21 and the frame-shaped member 22 arranged with the MEA 10 interposed therebetween are sealed and fixed by an adhesive 110.

  In the fuel cell 1 having a plurality of single cell 25 structures, frame-like members 21 and 22 are arranged on both sides of the MEA 10, and opposite to the surface of the frame-like members 21 and 22 on which the MEA 10 is arranged. A plurality of structures each having separators 23 and 24 disposed on the side surface are provided, and a terminal 33, an insulator 31, and an end plate 32 are disposed at both ends of the cell stacking direction to form a stack 33. A fastening member 34 (for example, a tension plate, a through bolt, etc.) that extends in the cell stacking direction outside the stack 33 and is fixed with a bolt 35 or a nut.

  In the fuel cell 1 having this configuration, even when ice is formed in the manifold, the rigidity of the single cell 25 is improved in a well-balanced manner in the plane. When the temperature of the stack 33 rises rapidly, it is possible to prevent the separators 23 and 24 and the frame-shaped members 21 and 22 from warping or cracking. Therefore, the fuel cell 1 with high performance and high reliability is obtained.

  In the present embodiment, the configuration of the manifold portions 40A and 40B of the frame-shaped members 21 and 22 is the same as that of the first base member 101, the highly rigid member 102, and the second base member 103. Although the case where the three-layer structure is provided has been described, the present invention is not limited to this, and the entire frame-shaped members 21 and 22 may be configured from the three-layer structure. Further, as long as the high-rigidity member 102 does not adversely affect the power generation of the fuel cell 1, for example, as shown in FIG. 6, the high-rigidity member 102 may be disposed on the surface facing the MEA 10, and as shown in FIG. You may arrange | position in the surface side which opposes the separator 23 (24).

  In the present embodiment, the case where the substantially plate-like high-rigidity member 102 is disposed has been described. However, the present invention is not limited to this, and as shown in FIG. A plurality of dots 101 (second base material portion 103) may be present. The shape of the high-rigidity member 102 can be arbitrarily selected as desired, such as a honeycomb structure.

  In addition to the high-rigidity member 102, a fibrous filler 105 may be provided as shown in FIG. In this case, the highly rigid member 102 and the fibrous filler 105 form a highly rigid portion. Further, as shown in FIG. 10, a spherical filler 106 may be provided in addition to the high-rigidity member 102. In this case, the high rigidity member 102 and the spherical filler 106 form a high rigidity portion. By doing in this way, the rigidity of the frame-shaped members 21 and 22 can further be improved.

  Furthermore, as shown in FIG. 11, a fibrous filler 105 may be provided instead of the high-rigidity member 102, and as shown in FIG. 12, a spherical filler 106 is provided instead of the high-rigidity member 102. You may set up. Further, the fibrous filler 105 and the spherical filler 106 may be mixed in the high-rigidity member 102. Furthermore, both the fibrous filler 105 and the spherical filler 106 may be used.

  In addition, in the present embodiment, as the high-rigidity member 102, the case where a material formed from a material having higher rigidity than the first base material portion 101 and the second base material portion 103 is used, Not limited to this, the high-rigidity member 102 has higher rigidity than the first base material portion 101 and the second base material portion 103, and the first base material portion 101 and the second base material portion 103. It is also possible to use a material having a property of higher thermal conductivity than that. By using such a material as a material for forming the high-rigidity member 102, in addition to the above-mentioned advantages, the thermal conductivity in the cell surface direction can be improved. For example, ice is formed in the manifold. However, when the temperature of the cooling water rises due to rapid warm-up operation or the like from below freezing point, the temperature of the manifold portion is likely to rise, and the ice formed in the manifold can be easily melted. In addition, the temperature difference in the cell plane can be reduced. This is particularly effective when a metal separator is provided.

It is a disassembled perspective view of the single cell for fuel cells concerning embodiment of this invention. It is a top view of the frame-shaped member which is a component of the single cell for fuel cells shown in FIG. It is an expanded sectional view along the III-III line shown in FIG. It is sectional drawing which shows a part of single cell for fuel cells concerning embodiment of this invention. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an overall schematic diagram of a fuel cell including a single cell for a fuel cell according to an embodiment of the present invention in a posture in which a cell stacking direction is a vertical direction. It is a figure corresponding to the cross section along the III-III line | wire shown in FIG. 2 concerning other embodiment of this invention. It is a figure corresponding to the cross section along the III-III line | wire shown in FIG. 2 concerning other embodiment of this invention. It is a figure corresponding to the cross section along the III-III line | wire shown in FIG. 2 concerning other embodiment of this invention. It is a figure corresponding to the cross section along the III-III line | wire shown in FIG. 2 concerning other embodiment of this invention. It is a figure corresponding to the cross section along the III-III line | wire shown in FIG. 2 concerning other embodiment of this invention. It is a figure corresponding to the cross section along the III-III line | wire shown in FIG. 2 concerning other embodiment of this invention. It is a figure corresponding to the cross section along the III-III line | wire shown in FIG. 2 concerning other embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Fuel cell, 10 ... MEA, 21, 22 ... Frame-shaped member, 23, 24 ... Separator, 25 ... Single cell, 101 ... 1st base material part, 102 ... High rigidity member, 103 ... 2nd base material Part, 105 ... fibrous filler, 106 ... spherical filler

Claims (8)

An electrolyte-electrode assembly in which an anode electrode is disposed on one surface of the electrolyte and a cathode electrode is disposed on the other surface; a frame-like member disposed on both sides of the electrolyte-electrode assembly; A single cell for a fuel cell comprising: a separator disposed on a surface opposite to a surface facing each electrolyte-electrode assembly of each frame-shaped member,
The frame-shaped member is a single cell for a fuel cell including a base material portion formed of a base material and a high-rigidity portion formed of a material having higher rigidity than the base material.   The single cell for a fuel cell according to claim 1, wherein the highly rigid portion includes a substantially plate-like member.   The single cell for a fuel cell according to claim 2, wherein the substantially plate-like member contains a metal.   The single cell for a fuel cell according to any one of claims 1 to 3, wherein the high-rigidity portion includes a fibrous filler.   The single cell for a fuel cell according to any one of claims 1 to 4, wherein the high-rigidity portion includes a spherical filler.   The single cell for a fuel cell according to any one of claims 1 to 5, wherein the frame-shaped member is formed with a manifold, and the high-rigidity portion is formed on an outer peripheral portion of the manifold.   The single cell for a fuel cell according to any one of claims 1 to 6, wherein the material having higher rigidity than the base material includes a material having higher thermal conductivity than the base material.   A fuel cell comprising the single cell for a fuel cell according to any one of claims 1 to 7.

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