Fuel cell stack

Abstract

To provide a fuel cell stack capable of preventing a drain pipe from coming out of a holding structure of an end plate.SOLUTION: A fuel cell stack includes: a cell laminated body; an end plate arranged at an end part of the cell laminated body; a manifold communicating with the cell laminated body and the end plate; and a drain pipe inserted into the manifold. The manifold of the end plate includes a holding structure for holding the end part of the drain pipe. The holding structure has a holding hole for holding the end part of the drain pipe, and an inclined surface inclined from the holding hole toward the inside of the manifold of the end plate. The inclined surface is inclined so that a central part of the drain pipe is closer to the inside of the cell laminated body than the end part of the drain pipe. The drain pipe is arranged along the inclined surface.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present disclosure relates to a fuel cell stack.

Background Art

[0002] Various technologies have been proposed regarding fuel cells as disclosed in Patent Document 1.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Patent Document 1 discloses a structure in which a drain pipe (straw) is provided in the manifold of a fuel cell stack. Since the position of the drain pipe shifts due to undulations or the like of the cell stack, the position of the drain pipe and the holding structure of the drain pipe provided on the end plate also shifts, and there is a possibility that the drain pipe may come out of the holding structure of the end plate.

[0005] The present disclosure has been made in view of the above circumstances, and the main object thereof is to provide a fuel cell stack capable of suppressing the drain pipe from coming out of the holding structure of the end plate.

Means for Solving the Problems

[0006] That is, the present disclosure includes the following aspects. <1> A fuel cell stack, wherein the fuel cell stack includes a cell stack, an end plate disposed at an end of the cell stack, a manifold communicating the cell stack and the end plate, A drain pipe inserted into the manifold, and The manifold of the end plate is provided with a holding structure for holding the end of the drain pipe. The holding structure has a holding hole for holding the end of the drain pipe and an inclined surface that inclines from the holding hole toward the inside of the manifold of the end plate. The inclined surface is inclined such that the central portion of the drain pipe is closer to the inside of the cell stack than the end portion of the drain pipe. The drain pipe is arranged along the inclined surface, a fuel cell stack.

[0007] <2> The fuel cell stack according to <1>, wherein the position of the holding hole is deviated within the allowable range of the tolerance of the cell stack from the rated position of the drain pipe.

Advantages of the Invention

[0008] The fuel cell stack of the present disclosure can suppress the drain pipe from coming out of the holding structure of the end plate.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Embodiments for Carrying Out the Invention

[0010] Hereinafter, embodiments according to the present disclosure will be described. Matters other than those specifically mentioned in this specification and necessary for the implementation of the present disclosure (for example, the general configuration and manufacturing process of a fuel cell stack that do not characterize the present disclosure) can be grasped as design matters of those skilled in the art based on the prior art in the relevant field. The present disclosure can be implemented based on the content disclosed in this specification and common general knowledge in the relevant field. Also, the dimensional relationships (length, width, thickness, etc.) in the drawings do not reflect the actual dimensional relationships. In the present disclosure, the gas supplied to the anode of the fuel cell is a fuel gas (anode gas), and the gas supplied to the cathode of the fuel cell is an oxidant gas (cathode gas). The fuel gas is mainly a gas containing hydrogen and may be hydrogen. The oxidant gas is a gas containing oxygen and may be oxygen, air, etc. In the present disclosure, the fuel gas and the oxidant gas are collectively referred to as reaction gas or gas.

[0011] In the present disclosure, a fuel cell stack wherein the fuel cell stack includes a cell laminate, an end plate disposed at an end of the cell laminate, a manifold communicating the cell laminate and the end plate, and a drain pipe inserted into the manifold, wherein a holding structure for holding an end of the drain pipe is provided in the manifold of the end plate, the holding structure having a holding hole for holding the end of the drain pipe and an inclined surface inclined from the holding hole toward the inside of the manifold of the end plate, the inclined surface being inclined such that the central portion of the drain pipe is closer to the inside of the cell laminate than the end of the drain pipe, the drain pipe being arranged along the inclined surface, provides a fuel cell stack.

[0012] It is necessary to provide a holding hole for a drain pipe for draining cell-generated water in the end plate of the fuel cell stack. FIG. 1 is a perspective schematic view showing an example of the periphery of a manifold of a conventional fuel cell stack. FIG. 2 is a cross-sectional schematic view showing an example of the periphery of a manifold of a conventional fuel cell stack. FIG. 1 is a perspective schematic view when viewing the end plate 50 with the resin sheet 40 interposed therebetween from the side of the cell stack 30. A conventional fuel cell stack has a holding hole 20 as a holding structure 70 for the drain pipe 10 in the manifold 60 of the end plate 50. In a conventional fuel cell stack, since there is a straight holding hole 20 with respect to the nominal position of the drain pipe 10, in the worst case of the tolerance of the cell stack 30, the drain pipe 10 is displaced to the worst tolerance position 11, and a force F that tries to pull out the drain pipe 10 from the holding hole 20 acts, and there is a possibility that the drain pipe 10 may come out of the holding hole 20 when the fuel cell stack is in use.

[0013] FIG. 3 is a perspective schematic view showing an example of the periphery of a manifold of a fuel cell stack of the present disclosure. FIG. 4 is a cross-sectional schematic view showing an example of the periphery of a manifold of a fuel cell stack of the present disclosure. FIG. 5 is a cross-sectional schematic view showing another example of the periphery of a manifold of a fuel cell stack of the present disclosure. FIG. 3 is a perspective schematic view when viewing the end plate 50 with the resin sheet 40 interposed therebetween from the side of the cell stack 30. The fuel cell stack of the present disclosure has a holding hole 20 and an inclined surface 21 as a holding structure 70 for the drain pipe 10 in the manifold 60 of the end plate 50. The inclined surface 21 is inclined such that the central portion of the drain pipe 10 is closer to the inside of the cell stack 30 than the end portion of the drain pipe 10. In the fuel cell stack of the present disclosure, due to the inclined surface 21, the position of the holding hole 20 is gradually changed by the worst tolerance 80 of the cell stack 30 and set, and the drain pipe 10 is guided so as to bend the drain pipe 10 in the direction R opposite to the force of the drain pipe 10 coming out of the holding hole 20. In the present disclosure, by providing the holding structure 70 having the inclined surface 21 inclined toward the inside of the manifold 60 of the end plate 50, the drain pipe 10 can be inclined in the direction R opposite to the direction in which the drain pipe 10 comes out, so that it is possible to suppress the drain pipe 10 from coming out of the holding structure 70 of the end plate 50. In the fuel cell stack of the present disclosure, even when the tolerance of the cell stack 30 is in the worst state, the central portion of the drain pipe 10 moves to the rated position, and the drain pipe 10 only becomes straight at the worst tolerance position 11, so that no force for the drain pipe 10 to come out of the holding structure 70 of the end plate 50 is generated.

[0014] The fuel cell stack of the present disclosure includes a cell stack in which a plurality of single cells (cells) of a fuel cell are stacked. In the present disclosure, both the cell and the fuel cell stack may be referred to as a fuel cell in some cases. The number of cells stacked in the cell stack is not particularly limited, and may be, for example, 2 to several hundred.

[0015] The cell may have a power generation body. The shape of the power generation body may be rectangular in plan view. The power generation body may be a membrane electrode assembly (MEA) including an electrolyte membrane and two electrodes sandwiching the electrolyte membrane. The electrolyte membrane may be a solid polymer electrolyte membrane. Examples of the solid polymer electrolyte membrane include fluorine-based electrolyte membranes such as thin films of perfluorosulfonic acid containing moisture, and hydrocarbon-based electrolyte membranes. The electrolyte membrane may be, for example, a Nafion membrane (manufactured by DuPont). One of the two electrodes is an anode (fuel electrode), and the other is a cathode (oxidant electrode). The electrode includes a catalyst layer and may optionally include a gas diffusion layer. The power generation body may be a membrane electrode gas diffusion layer assembly (MEGA). In this case, the cell may include a cathode separator, an anode separator, and a membrane electrode gas diffusion layer assembly disposed between the cathode separator and the anode separator. The membrane electrode gas diffusion layer assembly has, in this order, an anode-side gas diffusion layer, an anode catalyst layer, an electrolyte membrane, a cathode catalyst layer, and a cathode-side gas diffusion layer. The anode catalyst layer and the cathode catalyst layer are collectively referred to as the catalyst layer. The anode-side gas diffusion layer and the cathode-side gas diffusion layer are collectively referred to as the gas diffusion layer. The catalyst layer contains a catalyst, and the catalyst may include a catalyst metal that promotes an electrochemical reaction, an electrolyte having proton conductivity, a carrier having electron conductivity, and the like. As the catalyst metal, for example, platinum (Pt), an alloy composed of Pt and other metals (for example, a Pt alloy mixed with cobalt, nickel, etc.) can be used. The catalyst metal used as the cathode catalyst and the catalyst metal used as the anode catalyst may be the same or different. As the electrolyte, a fluororesin or the like may be used. As the fluororesin, for example, Nafion solution or the like may be used. The above catalyst metal is supported on a carrier, and in each catalyst layer, the carrier supporting the catalyst metal (catalyst-supporting carrier) and the electrolyte may be mixed. Examples of the carrier for supporting the catalyst metal include carbon materials such as commercially available carbon. The gas diffusion layer (GDL) may be composed of a base material and a mesoporous layer (MPL). The GDL may have a base material on the side in contact with the separator and an MPL on the side in contact with the catalyst layer. The base material may be a conductive member having gas permeability or the like. Examples of the base material include carbon porous bodies such as carbon cloth and carbon paper, and metal porous bodies such as metal mesh and foamed metal. The MPL may contain a mixture of a water-repellent resin such as PTFE and a conductive material such as carbon black. The MPL may contain an antioxidant such as Ce. The antioxidant can prevent the generation of radicals. The cell may include an insulating resin frame disposed on the outer side (outer periphery) in the plane direction of the membrane electrode assembly between the anode separator and the cathode separator. The resin frame is formed into a plate-like and frame-like shape using a thermoplastic resin, and seals the space between the anode separator and the cathode separator while holding the membrane electrode assembly in its central region. As the resin frame, for example, resins such as PE, PP, PET, and PEN can be used. The resin frame may be a three-layer sheet composed of three layers with an adhesive layer disposed on the surface layer.

[0016] The cell may have a separator. The separator collects the current generated by power generation and functions as a partition. In a fuel cell, the separator is usually disposed on both sides in the stacking direction of the power generation body such that a pair of separators sandwich the power generation body. One of the pair of separators is an anode separator and the other is a cathode separator. The anode separator may have grooves serving as fuel gas flow paths on the surface facing the power generation body. The cathode separator may have grooves serving as oxidant gas flow paths on the surface facing the power generation body. Examples of the separator may include dense carbon obtained by compressing carbon to make it gas-impermeable, and press-molded metals (for example, iron, aluminum, and stainless steel, etc.). The separator may have holes that constitute a manifold such as supply holes and discharge holes for allowing fluids such as reaction gases and refrigerant to flow in the stacking direction of the cell. Examples of the refrigerant include water, a mixed solvent of water and ethylene glycol, and the like.

[0017] The fuel cell stack may have a gasket, a resin sheet, etc. between cells and between the cell stack and the end plate in order to seal each gas. The resin sheet may be the resin frame described above.

[0018] The fuel cell stack of the present disclosure includes an end plate disposed at an end of the cell stack. The end plate may be disposed at one end in the stacking direction of the cells of the cell stack, or may be disposed at both ends. The cell stack may be sandwiched between two end plates. The fuel cell stack of the present disclosure includes a manifold that communicates with the cell stack and the end plate. The manifold may be a fuel gas manifold or an oxidant gas manifold. The fuel cell stack of the present disclosure may include a fuel gas manifold and an oxidant gas manifold. A holding structure for holding an end of a drain pipe is provided in the manifold of the end plate. The holding structure has a holding hole for holding an end of the drain pipe and an inclined surface that inclines from the holding hole toward the inside of the manifold of the end plate. The inclined surface is inclined such that the central portion of the drain pipe is closer to the inside of the cell stack than the end of the drain pipe.

[0019] The fuel cell stack of the present disclosure includes a drain pipe inserted into the manifold. The drain pipe is disposed along the inclined surface of the holding structure of the manifold. The position of the holding hole of the holding structure of the manifold may be deviated within the tolerance range of the cell stack from the rated position of the drain pipe, may be deviated by the worst tolerance, or may be deviated in a direction opposite to the cell stack.

Description of Reference Numerals

[0020] 10 Drain pipe 11 Drain pipe disposed at the worst tolerance position of the cell stack 20 Holding hole 21 Inclined surface 30-cell laminate 40 resin sheet 50 end plate 60 manifold 70 holding structure 80 worst tolerance

Claims

1. A fuel cell stack, The fuel cell stack includes a cell stack and an end plate disposed at an end of the cell stack; a manifold that connects the cell stack and the end plate; a drain pipe inserted into the manifold; The manifold of the end plate is provided with a holding structure that holds the end of the drain pipe, The holding structure has a holding hole that holds the end of the drain pipe, and an inclined surface that is inclined from the holding hole toward the inside of the manifold of the end plate, The inclined surface is inclined so that the center of the drain pipe is closer to the inside of the cell stack than the end of the drain pipe, The fuel cell stack, wherein the drain pipe is arranged along the inclined surface.

2. 2. The fuel cell stack according to claim 1, wherein the position of the retaining hole is offset from the rated position of the drain pipe within an allowable range of tolerance of the cell stack.

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