JP6008202B2 - Fuel cell stack - Google Patents

Description

  The present invention relates to a fuel cell stack in which end plates are arranged at both ends of a cell stack in which a plurality of fuel cells are stacked.

  In general, a fuel cell stack includes, for example, a cell stack formed by stacking a plurality of fuel cell cells composed of a membrane electrode assembly, a gas diffusion layer, a separator, and the like, and a pair of end plates. For example, it is formed by tightening with bolts and nuts). Each fuel cell needs to be supplied with a fuel gas (for example, hydrogen), an oxidizing gas (for example, air), or a cooling medium (for example, cooling water) for preventing overheating of the fuel cell. For this reason, the end plates arranged at both ends of the fuel cell stack include manifolds that serve as inlets and outlets for allowing the gas or refrigerant to flow through the stack.

  In such an end plate, it is necessary to firmly fix it with bolts, etc., and it is required that the plate itself is strong enough to prevent mechanical deformation or distortion even if a predetermined fastening force is exerted. Is done. For this reason, the end plate is usually formed using a metal plate.

  As a fuel cell stack using a metal plate end plate, for example, a fuel cell stack described in Patent Document 1 below has been proposed. The end plate used in the fuel cell stack described in Patent Document 1 below is configured by laminating a plurality of thin metal plates formed of titanium alloy or the like. By laminating a plurality of thin metal plates, the number of thin metal plates can be adjusted according to the requirements of the cell stack. By adjusting the number of thin metal plates and increasing the plate thickness of the end plate, it is possible to improve the bending strength and rigidity of the end plate.

  However, in the fuel cell stack described in Patent Document 1 described below, as the required bending strength and rigidity increase, the number of thin metal plates increases, so the weight of the end plate increases. For this reason, when the fuel cell stack is mounted on the vehicle, there is a problem that the inertial impact force at the time of the vehicle collision increases and the possibility of the fuel cell stack being damaged increases.

  On the other hand, in the end plate for a fuel cell stack described in Patent Document 2 below, as a material used for the end plate, a high-strength resin material is selected instead of a heavy metal material to reduce the weight of the end plate. Have been proposed.

JP 2009-266431 A JP 2001-236882 A

  Since the end plate for a fuel cell stack described in Patent Document 2 uses a resin material, the problem of the size of the weight due to the end plate of the metal plate described in Patent Document 1 is solved to some extent. It seems to be. However, since the end plate continuously receives a high pressure over the entire surface, there is a concern of a creep phenomenon in which the deformation increases with the passage of time when the end plate is molded from a resin material. Furthermore, it is usual to attach auxiliary equipment such as hydrogen pumps and gas-liquid separators, which are hydrogen parts for supplying hydrogen gas to the fuel cell stack, on the surface of the end plate. In order to ensure the surface accuracy, it is necessary to perform a cutting process on the surface to be attached. In this cutting process, since the processing time is several hours, there is a problem that the manufacturing cost is increased.

  The present invention has been made in view of such a problem, and an object thereof is to reduce the manufacturing cost of the end plate while reducing the weight while maintaining the strength and rigidity of the end plate. It is to provide a fuel cell stack that can be used.

  In order to solve the above problems, a fuel cell stack according to the present invention is a fuel cell stack in which end plates are arranged at both ends of a cell stack in which a plurality of fuel cells are stacked, A metal plate; and a second metal plate in which a plurality of polygonal hollow portions formed so as to penetrate along the stacking direction of the fuel cells are arranged at intervals, the first metal plate and the A plurality of second metal plates are alternately stacked.

  In the fuel cell stack according to the present invention, a first metal plate, and a second metal plate in which a plurality of polygonal hollow portions penetratingly formed along the stacking direction of the fuel cells are arranged at intervals from each other, Since the end plate in which a plurality of layers are alternately stacked is provided, it is possible to reduce the weight of the end plate while maintaining the rigidity of the end plate.

  In the fuel cell stack according to the present invention, it is also preferable that the second metal plate has a honeycomb structure in which the hollow portion has a hexagonal cross section.

  In this preferred embodiment, since the second metal plate has a honeycomb structure, it is possible to reduce the weight of the end plate while maintaining the same degree of rigidity as that of the end plate manufactured using only the metal plate. As a result, the possibility of damage to the fuel cell stack at the time of a vehicle collision can be reduced.

  In the fuel cell stack according to the present invention, the first metal plate may include a third metal plate on a side on which a hydrogen-based component for supplying hydrogen gas to the fuel cell is attached, and the third metal plate. It is also preferable to provide a heat insulating layer between the adjacent second metal plates.

  In this preferred embodiment, since the heat insulating layer is provided between the third metal plate on the side where the hydrogen-based parts of the end plate are attached and the second metal plate having a hollow portion adjacent to the third metal plate, The heat propagation direction can be limited to the end plate surface direction. As a result, heat dissipation in the end plate can be promoted.

  In the fuel cell stack according to the present invention, it is also preferable that a portion of the third metal plate to which the hydrogen-based component is attached is formed thinner than other portions.

  In this preferred embodiment, the heat capacity of the part to which the hydrogen-based part is attached can be reduced by forming the metal plate of the part to which the hydrogen-based part is attached in the end plate thinly. As a result, heat generated in the hydrogen-based component can be easily propagated in the surface direction of the metal plate, and thus heat dissipation can be promoted.

  According to the present invention, there is provided a fuel cell stack including an end plate that can be reduced in weight while maintaining the same strength and rigidity as a conventional end plate formed of a high-strength, high-rigidity metal lump. Can do. Further, according to the present invention, since the end plate is configured by laminating metal plate materials, it is possible to reduce the cutting process in the portion where the auxiliary equipment such as a hydrogen pump on the surface of the end plate is attached. As a result, a fuel cell stack capable of reducing the manufacturing cost can be provided.

1 is a side view showing a schematic configuration of a fuel cell stack according to an embodiment of the present invention. It is a top view of the end plate with which the fuel cell stack concerning the embodiment of the present invention is provided. It is a top view of the irregular cross-section metal plate with which the fuel cell stack concerning the embodiment of the present invention is provided. It is sectional drawing of the end plate with which the fuel cell stack concerning 2nd Embodiment of this invention is provided. It is sectional drawing of the end plate with which the fuel cell stack concerning 3rd Embodiment of this invention is provided.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a side view showing a schematic configuration of a fuel cell stack 1 according to the first embodiment of the present invention.

  The fuel cell stack 1 is a solid polymer fuel cell having a solid polymer separation membrane, and is a cell stack 3 in which a plurality of fuel cells 2 each composed of an electrolyte membrane, an anode, a cathode, and a separator are stacked. have. The electrolyte membrane is a proton-conductive ion exchange membrane formed of a fluorine-based solid polymer material. Between the anode and the cathode, a flow path for hydrogen gas and oxidizing gas is formed. Both the anode and the cathode are made of carbon cloth woven from carbon fibers. The separator is formed of a gas-impermeable conductive member such as dense carbon which is compressed by gas and impermeable to gas.

  The fuel cell stack 1 is fixed to the end plates 10A and 10B. The end plates 10A and 10B are fastened by applying a load in the stacking direction with bolts and nuts (not shown) so as to sandwich the cell stack 3. In the embodiments described below, the direction in which the fuel cells are stacked corresponds to the “stacking direction”, and the direction substantially perpendicular to the stacking direction corresponds to the “plane direction”.

  Next, the metal thin plate 31 (first metal plate) and the modified cross-section metal plate 41 (second metal plate) constituting the end plate 10 will be described with reference to FIG. FIG. 2A is a plan view of the end plate 10. FIG. 2B is a cross-sectional view of the end plate 10. 2C is a cross-sectional view taken along line AA of the end plate 10 illustrated in FIG.

  As shown in FIGS. 2A, 2B, and 2C, the end plate 10 is configured by alternately laminating a plurality of thin metal plates 31 and deformed cross-section metal plates 41. That is, when the end plate 10 is viewed in the stacking direction, the thin metal plate 31c, the deformed cross section metal plate 41b, the thin metal plate 31b, the deformed cross section metal plate 41a, and the thin metal plate 31a are stacked in this order. The number of stacked thin metal plates 31 and deformed cross-section metal plates 41 can be adjusted, and the number is appropriately determined according to the number of stacked cell stacks 3, the characteristics of the fuel cell 2, and the like. In the present embodiment, the surfaces 10a and 10b of the end plate 10 are both formed of a metal plate that has not been processed into a honeycomb structure, that is, a metal thin plate 31a and a metal thin plate 31c.

  For example, an aluminum plate material is used for the metal thin plate 31a, the metal thin plate 31b, and the metal thin plate 31c. The metal thin plate 31a, the metal thin plate 31b, and the metal thin plate 31c are, for example, metal plates having a thickness of about 5 mm, and preferably have the same thickness. Bolt holes 21 and through holes 22 are formed in the metal thin plate 31a, the metal thin plate 31b, and the metal thin plate 31c. A plurality of bolt holes 21 are provided at the outer peripheral ends of the metal thin plate 31a, the metal thin plate 31b, and the metal thin plate 31c. A plurality of through holes 22 are provided in the vicinity of both ends in the longitudinal direction of the metal thin plate 31a, the metal thin plate 31b, and the metal thin plate 31c so as to penetrate from the front surface to the back surface.

  For example, an aluminum plate material is used for the modified cross-section metal plate 41a and the modified cross-section metal plate 41b. It is preferable that the modified cross-section metal plate 41a and the modified cross-section metal plate 41b have the same thickness. Similar to the metal thin plate 31, the bolt hole 21 and the through hole 22 are formed in the modified cross-section metal plate 41 a and the modified cross-section metal plate 41 b.

  The metal thin plate 31 and the modified cross-section metal plate 41 are manufactured by, for example, forming an aluminum plate material into a thin plate having a certain thickness by pressing. At the same time, a bolt hole 21 and a through hole 22 penetrating from the front surface to the back surface are formed by pressing. The irregular cross-section metal plate 41 is processed into a honeycomb structure by press punching at portions other than the bolt holes 21 and the through holes 22 (details will be described later). Thereby, the metal thin plate 31 and the irregular cross-section metal plate 41 are produced. Then, the manufactured metal thin plate 31 and the modified cross-section metal plate 41 are arranged so as to be stacked in the number of layers that can obtain the strength and rigidity required for the cell laminate 3 and the like. The end plate 10 is manufactured by applying a clad material to the surface and fixing by means of applying heat or fixing with bolts.

  As shown in FIG. 2C, when the thin metal plate 31 and the odd-shaped cross-section metal plate 41 are laminated, the through holes 22 are formed at positions where they overlap each other. By overlapping each other, a flow path is formed between the end plate 10 and the cell stack 3. Via this flow path, fluid such as hydrogen gas, oxidizing gas, and cooling medium can be introduced or discharged into the cell stack 3.

  A hydrogen-based component 25 is mounted on one surface 10a of the end plate 10, that is, the surface of the thin metal plate 31a. The hydrogen system part 25 is a part for supplying hydrogen gas to the fuel battery cell 2, and includes an unillustrated hydrogen inlet valve, a regulator, a hydrogen pump, a gas-liquid separator, a hydrogen discharge valve, and other auxiliary machines, and these Includes connected piping. The part to which the auxiliary machines and the like are attached is required to have a certain level of surface accuracy since sealing performance is required. In order to ensure this surface accuracy, a conventional end plate which is not a type in which metal plate materials are laminated needs to cut the surface, and much time has been spent on the cutting. The end plate 10 of the present embodiment is configured by laminating metal plate materials, and since the surface 10a is an aluminum plate material formed by pressing, a certain degree of surface accuracy can be ensured. For this reason, it can be used without cutting the part to which the auxiliary machinery or the like is attached, and the processing time can be shortened. As a result of shortening the processing time, the manufacturing cost of the end plate 10 can be reduced.

  Next, the structure of the modified cross-section metal plate 41 included in the end plate 10 will be described in more detail with reference to FIG. FIG. 3 is a sectional view taken along line BB of the end plate 10 shown in FIG.

  The odd-shaped cross-section metal plate 41 is a polygonal shape (in the present embodiment, regular hexagon) formed through the metal plates 42a and 42b (for example, aluminum plate material) disposed around the through hole 22 and the stack direction of the fuel cells 2. A hollow structure 43 having a rectangular shape or a part of which is cut away) has a honeycomb structure section 44 in which a plurality of hollow sections 43 are arranged at intervals. The hollow portion 43 is formed so as to penetrate from the front surface to the back surface of the modified cross-section metal plate 41.

  The metal plates 42 a and 42 b have a width that is approximately the same as or slightly larger than the width of the through hole 22, and is formed so as to cover the through hole 22. In addition to the portions where the metal plates 42a and 42b are formed, a honeycomb structure portion 44 is formed in which a plurality of hollow portions 43 that have been subjected to punching are arranged at intervals. From the viewpoint of further reducing the weight of the end plate 10, it is preferable that the honeycomb structure portion 44 is formed in a wide range in a portion other than the portion where the through hole 22 or the like is formed. The honeycomb structure portion 44 has a large number of vertical structures in which metal thin plates have a hexagonal shape. For this reason, the honeycomb structure part 44 has a characteristic strong against compression in the stacking direction.

  As described above, the end plate 10 includes the modified cross-section metal plate 41 having the honeycomb structure portion 44, so that the end plate 10 has the same strength and rigidity as an end plate formed only of a metal plate such as a conventional titanium alloy. It is possible to provide the end plate 10 that can be reduced in weight while maintaining the above. As a result, when the fuel cell stack 1 including the end plate 10 is mounted on a vehicle, the inertial impact force at the time of the vehicle collision can be reduced, so that the possibility of the fuel cell stack 1 being damaged can be reduced.

  Next, the fuel cell stack 1 according to the second embodiment of the present invention will be described with reference to FIG. The end plate 10 shown in FIG. 4 is obtained by forming a heat insulating layer 51 having heat insulating performance on the end plate 10 in the fuel cell stack 1 shown in the first embodiment, and other configurations and functions are the first embodiment. This is the same as the fuel cell stack 1 of FIG. Therefore, the same reference numerals as those of the first embodiment are used for the same portions as those of the end plate 10 in the fuel cell stack 1 of the first embodiment, and description thereof is omitted.

  The heat insulation layer 51 is disposed between a metal thin plate 31a (third metal plate) to which auxiliary equipment as the hydrogen-based component 25 is attached and a modified cross-section metal plate 41a adjacent to the metal thin plate 31a. As a result, when the cross section of the end plate 10 is viewed downward from the metal thin plate 31a to which the accessories are attached, the metal thin plate 31a, the heat insulating layer 51, the deformed cross section metal plate 41a, the metal thin plate 31b, and the deformed cross section metal. The plate 41b and the thin metal plate 31c are stacked in this order. The heat insulation layer 51 is formed by, for example, a metal plate made of aluminum or the like coated with a resin and has a heat insulation property. For this reason, when heat propagates in the plate thickness direction of the end plate 10, the heat propagation direction can be limited. The heat insulating layer 51 is preferable if it has low thermal conductivity and is inexpensive. As a material of the heat insulation layer 51, PP material, PA material, etc. (PA6T-GF etc.) are mentioned, for example. In addition, resin is insert-molded in the through hole 22 to prevent insulation and corrosion. By making the material of the heat insulating layer 51 the same as the resin in the through hole 22, peeling of the heat insulating layer 51 is suppressed. can do. In addition, as a method of providing the heat insulating layer 51, processed resin plates (through holes formed) may be stacked and provided.

  In producing the end plate 10 in the present embodiment, first, the deformed cross-section metal plate 41 is formed by pressing. And the end plate 10 is produced by superimposing the thin metal plate 31, the heat insulating layer 51, and the odd-shaped cross-section metal plate 41, and using bolt fastening, resin insert molding, or the like.

  In this way, when the heat generated from the auxiliary equipment is propagated in the thickness direction of the end plate 10 by laminating the heat insulating layer 51 between the thin metal plate 31a and the odd-shaped cross-section metal plate 41 in the end plate 10. The heat propagation direction can be limited to the surface direction of the end plate 10. As a result, the weight of the end plate 10 can be reduced and the manufacturing cost can be reduced. In addition, heat dissipation in the end plate 10 is promoted, and heat is trapped in the honeycomb structure portion 44 formed in the deformed cross-section metal plate 41. Can be suppressed.

  Next, the fuel cell stack 1 according to the third embodiment of the present invention will be described with reference to FIG. The end plate 10 shown in FIG. 5 is obtained by reducing the thickness of the metal thin plate 31a on the side where the auxiliary equipment as the hydrogen-based component 25 in the end plate 10 shown in the first embodiment is attached. The function is the same as that of the fuel cell stack 1 of the first embodiment. Therefore, the same reference numerals as those of the first embodiment are used for the same portions as those of the end plate 10 in the fuel cell stack 1 of the first embodiment, and description thereof is omitted.

  As shown in FIG. 5, in the metal thin plate 31a on the side on which the accessories are attached, the thickness of the portion 61 to which the accessories are attached is formed thinner than the thickness of the metal thin plate 31a in the other portions. As the production of the end plate 10 in the present embodiment, first, a thin metal plate 31a is formed by thinning only a portion to which accessories are attached by forging a thin metal plate such as aluminum. Next, the irregular cross-section metal plate 41 is formed by pressing. Then, the metal thin plate 31a having a thin plate thickness only at the site where the accessories are attached, the metal thin plates 31b and 31c not partially thinned, and the deformed cross-section metal plate 41 are combined and baked and bolted Then, the end plate 10 is produced using resin insert molding or the like.

  Thus, by reducing the plate thickness of the accessory mounting surface of the metal thin plate 31a, the heat capacity of the accessory mounting surface of the metal thin plate 31a can be lowered. For this reason, the heat generated by the auxiliary machinery can be easily propagated in the surface direction of the metal thin plate 31a. As a result, the weight of the end plate 10 can be reduced and the manufacturing cost can be reduced. In addition, the heat dissipation of the end plate 10 can be promoted.

  As mentioned above, although the Example of this invention was described, this is an illustration for description of this invention, Comprising: It is not the meaning which limits the scope of the present invention only to this Example. The present invention can be implemented in various other embodiments.

1: Fuel cell stack 2: Fuel cell 3: Cell stack 10: End plate 21: Bolt hole 22: Through hole 25: Hydrogen-based component 31: Metal thin plates 31a, 31b, 31c: Metal thin plate (first metal plate)
41a, 41b: Deformed cross-section metal plate (second metal plate)
43: Hollow part 44: Honeycomb structure part 51: Heat insulation layer

Claims (3)

A fuel cell stack in which end plates are arranged at both ends of a cell stack in which a plurality of fuel cells are stacked,
The end plate includes a first metal plate, and a second metal plate in which a plurality of polygonal hollow portions penetratingly formed along the stacking direction of the fuel cells are arranged at intervals.
A plurality of the first metal plates and the second metal plates are alternately laminated ,
The fuel cell stack, wherein the second metal plate has a honeycomb structure in which the hollow portion has a hexagonal cross section . Of the first metal plate, between a third metal plate on the side where a hydrogen-based component for supplying hydrogen gas to the fuel cell is attached and the second metal plate adjacent to the third metal plate a fuel cell stack according to claim 1, characterized in that is provided with a heat insulating layer. 3. The fuel cell stack according to claim 2 , wherein a portion of the third metal plate to which the hydrogen-based component of the third metal plate is attached is formed thinner than other portions.

Images