JP2018081861A - Fuel cell stack and manufacturing method of fuel cell stack - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fuel cell stack superior in power generation performance and durability by preventing a film from getting damaged due to an excessive load during fastening (assembling) of the fuel cell stack.SOLUTION: The fuel cell stack includes: a cell laminated body having plural cells laminated; a pair of collector plate which is disposed at each of both ends of the cell laminated body in a lamination direction of the cells; an elastic member which is disposed at the different side from the cell of the collector plate; and a pair of end plates which sandwich the cell laminated body, the elastic member and the collector plates therebetween. The pair of end plates includes: plural types of first engage parts; plural types of second engage parts and plural pins for fixing the first engage part and the second engage part.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method for stacking and fastening a plurality of flat plate components such as a fuel cell stack.

The fuel cell stack is a structure in which unit cells of fuel cells are stacked. The unit cell module includes a polymer electrode membrane and a membrane electrode assembly (hereinafter also referred to as “MEA”) having a pair of catalyst electrodes sandwiching the polymer electrolyte membrane and a pair of membrane electrode assemblies. And a separator.

  The polymer electrolyte membrane is composed of an electrolyte having a fluororesin ion exchange membrane having a sulfonic acid group or a polymer ion exchange membrane such as a hydrocarbon resin ion exchange membrane.

  The catalyst electrode is located on the polymer electrolyte membrane side, and includes a catalyst layer that promotes a redox reaction in the catalyst electrode, and a gas diffusion layer that is located outside the catalyst layer and has air permeability and conductivity. . Furthermore, the gas diffusion layer is located on the catalyst layer side, and a carbon coating layer for improving the contact property with the catalyst layer, and a gas diffusion base material for diffusing a gas supplied from the outside and supplying the catalyst layer Composed of layers. The catalyst layer of the fuel electrode that is the electrode on the side through which the fuel gas flows includes platinum or an alloy of platinum and ruthenium, for example, and the catalyst layer of the air electrode that is the electrode on the side through which the oxidizing gas flows includes, for example, Examples include platinum and alloys of platinum and cobalt.

  The separator is a conductive member for preventing the fuel gas supplied to the fuel electrode and the oxidizing gas supplied to the air electrode from being mixed.

  The fuel cell stack is electrically connected in series by stacking such unit cell modules. In addition, a general fuel cell stack structure includes a pair of end plates sandwiching a cell stack in which unit cell modules are stacked and fixed from both ends with connecting bolts or the like.

  By supplying the fuel cell (including hydrogen) and the oxidizing gas (including oxygen) to each unit cell module of the fuel cell stack having such a configuration, electric energy can be continuously taken out. . Hereinafter, a chemical reaction caused by supplying the fuel gas and the oxidizing gas to the single cell will be described.

  The hydrogen molecules supplied to the fuel electrode are separated into hydrogen ions and electrons by the catalyst layer of the fuel electrode. Hydrogen ions move to the air electrode side through the humidified polymer electrolyte membrane. On the other hand, the electrons move through the external circuit to the air electrode to which the oxidizing gas is supplied. At this time, electrons passing through the external circuit can be used as electric energy. In the catalyst layer of the air electrode, hydrogen ions that have moved through the polymer electrolyte membrane, electrons that have moved through the external circuit, and oxygen supplied to the air electrode react to generate water. Further, heat is generated by the above-described chemical reaction.

  Thus, by supplying the fuel gas and the oxidizing gas to the fuel cell, electric energy and thermal energy can be obtained simultaneously. For this reason, the fuel cell stack is being used as a home cogeneration system that requires power generation and hot water supply.

  Patent Documents 1 to 3 propose tightening the fuel cell stack with a fastening bolt or fastening with a metal belt.

International Publication No. 2010/070849 International Publication No. 2010/090003 JP 2010-277869 A

  In recent years, there has been a demand for further cost reduction of fuel cell materials. In particular, MEA, and in particular, polymer electrolyte membranes (hereinafter referred to as membranes) are important components that affect performance and cost is high. Inexpensive membranes are being developed.

  However, since a thin and inexpensive film has a low mechanical strength, the film is damaged by a load applied at the time of fastening, which causes a problem that power generation efficiency and battery life are reduced.

  The fuel cell stack having the structure of Patent Documents 1 to 3 has a structure that equalizes the load applied to the cell stack. However, in the fuel cell stack having the structure of Patent Documents 1 to 3, a load is applied to the cell stack. For this reason, it is necessary to apply a load larger than a predetermined fastening state to the cell stack, and there is a problem that the load at this time damages the film.

  The present invention solves the conventional problems, and provides a fuel cell stack excellent in power generation performance and durability by preventing membrane damage due to an excessive load during fastening (assembly) of the fuel cell stack. For the purpose.

  In order to achieve the above object, a cell stack in which a plurality of cells are stacked, current collectors disposed at both ends of the cell stack in the cell stacking direction, and each of the current collector plates An elastic member disposed on a side different from the cell, and a pair of end plates that sandwich the cell stack, the elastic member, and the current collector plate, and the pair of end plates, A fuel cell stack having a plurality of types of first engaging portions, a plurality of types of second engaging portions, and a plurality of pins for fixing the first engaging portions and the second engaging portions is used.

  In addition, a cell stack in which a plurality of cells are stacked, current collectors disposed at both ends of the cell stack in the cell stacking direction, and an elastic member disposed at an end of the current collector A combination of the first engaging portion and the second engaging portion provided on each of the pair of end plates while pressing the stacked layered body between the pair of end plates. Then, a setting process of fixing with two kinds of pins and a method of manufacturing a fuel cell stack are used.

  With the above configuration, when the fuel cell stack is fastened (assembled), an excessive load is not applied to the cell stack, so the fuel cell stack has excellent power generation performance and durability without damage to the membrane. Can provide.

Sectional drawing of the fuel cell stack in the embodiment of the present invention (A) The perspective view which shows the relationship with the end plate and pin in embodiment, (b) The enlarged plan view of the connection part when combining an end plate (A)-(c) The enlarged view of the 3rd engaging part and the 4th engaging part at the time of pin insertion in embodiment, (d) The perspective view of the pin in embodiment (A)-(c) The enlarged view of the 5th engaging part and the 6th engaging part at the time of pin insertion in embodiment, (d)-(e) The perspective view of the pin in embodiment (A)-(d) Sectional drawing of the pin in embodiment Schematic diagram of pin rotation component in the embodiment The side view which shows the edge part bending shape of the pin in (a)-(b) embodiment

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
(Embodiment 1)
FIG. 1 is a cross-sectional view of a fuel cell stack according to Embodiment 1 of the present invention. As shown in FIG. 1, the fuel cell stack 1 has a cell stack 7 formed by stacking a plurality of unit cell modules 2 at the center thereof. In the final layer at one end of the cell stack 7, a current collector plate 3, a plurality of pipes 5, and an end plate 4a as a fastening member are arranged. In the final layer at the other end of the cell stack 7, a current collector plate 3, an elastic body 6 including, for example, a plurality of inner springs, and an end plate 4 b as a fastening member are disposed. Then, the current collector plate 3, the pipe 5, and the cell stack 7 are tightened with a pair of end plates 4 a and 4 b such as a resin via the elastic body 6 to constitute the fuel cell stack 1.

  The material of the end plates 4a and 4b is preferably a high-strength resin excellent in moldability. Examples of such materials include thermoplastic resins such as polyphenylene sulfide and thermosetting resins such as phenol resins. In particular, the material is not limited, and a configuration in which a metal and a resin are integrally molded, a partially divided configuration, or a combination of a metal plate and a resin plate may be used.

  The plurality of pipes 5 are pipes for supplying and discharging fuel gas, oxidant gas, and refrigerant to and from the cell stack 7, but the number of pipes 5 is not particularly specified, and is the same component as any of the end plates. It may be formed as.

  FIG. 2A is a perspective view showing the relationship between the end plates 4a and 4b and the pin 10 in the embodiment. FIG. 2B is an enlarged plan view of the first engaging portion 9a and the second engaging portion 9b when the end plates 4a and 4b are combined.

  The end plates 4a and 4b have a box shape. The end plate 4 a and the end plate 4 b are opposed to each other at the opening portion 17. A plurality of first engaging portions 9a and second engaging portions 9b are provided at predetermined intervals along the edge portions 8a and 8b on the edge portions 8a and 8b which are two opposite sides of the opening portion 17. Yes.

  Arrangement with the 1st engaging part 9a and the 2nd engaging part 9b is arranged alternately, and when the end plates 4a and 4b are combined so as to face each other, it is orthogonal to the stacking direction X of the cell stack 7. A through-hole 18 penetrating in the direction Y to be formed can be formed.

  The first engaging portion 9a and the second engaging portion 9b have hook shapes. The pin 10 can be inserted into the through hole 18. The number of the first engaging portions 9a and the second engaging portions 9b is not particularly defined, and can be freely set according to the fastening load and the strength of the end plates 4a and 4b. Moreover, the opening surface of the end plates 4a and 4b has a rectangular shape. It is preferable that the edge portions 8a and 8b provided with the first engagement portion 9a and the second engagement portion 9b are on the long side in the opening surfaces of the end plates 4a and 4b. This is because the stress generated in the first engaging portion 9a and the second engaging portion 9b can be reduced. However, it does not necessarily need to be a long side, and can also be configured on the short side.

  It is preferable that the end plates 4a and 4b have the same shape. The end plates 4a and 4b can be easily manufactured. Moreover, since it can clamp with the end plates 4a and 4b of the same shape, the balance of the load concerning the cell laminated body 7 can be improved. The cell laminate 7 can be evenly loaded.

  However, the configuration is not limited to this, and the end plates 4a and 4b may be configured in different shapes. Further, the end plates 4a and 4b may be provided with a through hole for providing the pipe 5, a rib shape for accurately arranging the elastic body 6, and the like.

  3A to 4D, details of the first engaging portion 9a and the second engaging portion 9b and the operation thereof will be described. There are two types of first engaging portion 9a and second engaging portion 9b. The third engagement portion 9c and the fourth engagement portion 9d in FIGS. 3A to 3C, and the fifth engagement portion 9e and the sixth engagement in FIGS. 4A to 4C. Part 9f.

  In the first engaging portion 9a and the second engaging portion 9b, there are more third engaging portions 9c and fourth engaging portions 9d than the fifth engaging portion 9e and the sixth engaging portion 9f. The fifth engaging portion 9e and the sixth engaging portion 9f are preferably located at the end portions of the first engaging portion 9a and the second engaging portion 9b. As will be described later, this is because the second pin 10b is inserted into the second through hole 18b.

  FIG. 3A is an enlarged plan view when the first pin 10a is inserted into the first through hole 18a in which the third engaging portion 9c and the fourth engaging portion 9d can be combined. Note that there are a plurality of first through holes 18a, which are arranged in a straight line to form through holes.

  FIG. 3B shows a state where the first pin 10a is rotated from FIG. FIG.3 (c) shows the case where the 1st pin 10a is rotated further from FIG.3 (b).

  Along with the rotation of the first pin 10a, the space between the end plate 4a and the end plate 4b is tightened.

  FIGS. 4A to 4C correspond to the states of FIGS. 3A to 3C, respectively.

  4 (a) to 4 (c), the second through hole 18b combined with the fifth engaging portion 9e and the sixth engaging portion 9f becomes larger as the first pin 10a rotates. It is preferable that there are a plurality of second through holes 18b. The first through hole 18a and the second through hole 18b have different shapes.

  Here, if it is fixed in the state of FIGS. 3B and 4B, the second pin 10b is inserted into the second through hole 18b, and the end plate 4a and the end plate 4b are fixed. Similarly, when it wants to fix in the state of FIG.3 (c) and FIG.4 (c), the 2nd pin 10b is inserted in the 2nd through-hole 18b. As the second pin 10b, a plurality of pins having different diameters are prepared as shown in FIG. Alternatively, as shown in FIG. 4D, pins having different diameters in the length direction are prepared. The second pin 10b cannot rotate in the second through hole 18b.

  As a result, the polymer electrolyte membrane (hereinafter referred to as a membrane) can be fixed at any time when the end plates 4a and 4b are fastened without applying an excessive load.

  The first pin 10a and the second pin 10b are only required to have a rigidity capable of exerting a fastening load, and the material is not particularly limited, but is preferably a metal or a fiber reinforced resin. It can be made of a material having a relatively high strength such as a material. In the embodiment, as an example, a chromium molybdenum steel material SCM435 is used.

  The cross-sectional shape of the first pin 10a is shown in FIGS. 5 (a) to 5 (d). The cross section of the first pin 10a has an elliptical shape, an oval shape, an oval shape, a semicircular shape, or the like, and a predetermined design is obtained when the first pin 10a is inserted so that the longitudinal direction of the cross section is the stacking direction of the cell stack 7 The dimension of each member is comprised so that a load may be applied to the cell laminated body 7. FIG.

Moreover, since the cross-sectional shape of the first pin 10a is not circular, the pin 10 can be easily rotated by temporarily attaching the rotating component 11 as shown in FIG. The rotating component 11 has a hole or opening 12. The pin 10 is inserted into the opening 12 and the pin 10 is turned.
Alternatively, the end of the first pin 10a may be bent as shown in FIGS. 7 (a) and 7 (b).

  With such a configuration and manufacturing method, when the cell stack 7 is fastened without using a bolt mechanism, it can be fastened without applying a load higher than a predetermined design load, and damage to the film can be prevented.

The polymer electrolyte fuel cell stack of the present invention is useful for a fuel cell used for a portable power source, a power source for an electric vehicle, a domestic cogeneration system, or the like.

DESCRIPTION OF SYMBOLS 1 Fuel cell stack 2 Single battery cell module 3 Current collecting plate 4a, 4b End plate 5 Pipe 6 Elastic body 7 Cell laminated body 8a, 8b Edge 9a 1st engaging part 9b 2nd engaging part 9c 3rd engaging part 9d Fourth engaging portion 9e Fifth engaging portion 9f Sixth engaging portion 10 Pin 10a First pin 10b Second pin X Stacking direction Y direction 11 Rotating component 12 Opening 17 Opening portion 18 Through hole 18a First through hole 18b Second through hole

Claims (9)

A cell stack in which a plurality of cells are stacked;
Current collectors disposed on both ends of the cell stack in the cell stacking direction;
An elastic member disposed on a different side of the current collector plate from the cell;
A pair of end plates that sandwich the cell stack, the elastic member, and the current collector plate;
Each of the pair of end plates includes a plurality of types of first engaging portions and a plurality of types of second engaging portions,
A plurality of pins for fixing the first engagement portion and the second engagement portion;
A fuel cell stack. The plurality of types of first engagement portions have a third engagement portion and a fifth engagement portion, and the plurality of types of second engagement portions have a fourth engagement portion and a sixth engagement portion. ,
The third engagement portion and the fourth engagement portion are combined to form a linear first through hole,
The fifth engagement portion and the sixth engagement portion are combined to form a linear second through hole,
The fuel cell stack according to claim 1, wherein the first through hole and the second through hole have different shapes. The fuel cell stack according to claim 1 or 2, wherein the first engagement portion and the second engagement portion are hook-shaped. The pin has a first pin and a second pin;
The fuel cell stack according to claim 2 or 3, wherein a first pin is inserted into the first through hole, and a second pin having a shape different from that of the first pin is inserted into the second through hole. The fuel cell stack according to claim 4, wherein the first pin has a circular cross section. 6. The fuel cell stack according to claim 4, wherein the first pin can rotate in the first through hole, and the second pin cannot rotate in the second through hole. The fuel cell stack according to any one of claims 2 to 6, wherein there are a plurality of the first engagement portions and a plurality of the second engagement portions, which are alternately combined, and there are a plurality of the first through holes. The fuel cell stack according to claim 7, wherein a shape of the first through hole is a shape in which a stacking direction of the cells is a longitudinal dimension. A cell stack in which a plurality of cells are stacked, current collectors disposed at both ends of the cells in the cell stacking direction, and an elastic member disposed at an end of the current collector; Laminating step of laminating,
While pressing the laminated body between a pair of end plates, the first and second engaging portions provided on each of the pair of end plates are combined and fixed with two types of pins. A setting process and a method of manufacturing a fuel cell stack

Images