JP2007087865A - Stack of fuel cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a small stack excellently mountable in a vehicle. <P>SOLUTION: This stack of a fuel cell is equipped with a plurality of membrane electrode assembly 1, a plurality of separators 2, a pair of end plates, bolts, and nuts. Each membrane electrode assembly 1 has an electrolyte membrane 3, a cathode pole 4 which is bonded to one surface of the electrolyte membrane 3 and to which air is supplied, and an anode pole 5 which is bonded to the other surface of the electrolyte membrane 3 and to which fuel is supplied. The separators 2 are each laminated while holding each membrane electrode assembly 1 between them, and each of them forms an air chamber 6 on each cathode pole 4 side, and a fuel chamber 7 on each anode pole 5 side. Each membrane electrode assembly 1 is held between nets made of a conductive metal. Both nets adjoing each other through each separator 2 are integrated by each welding part 20 together with the separator 2 so that cells 10 are each laid in series at the end part in the direction perpendicular to the laminated direction. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a stack of fuel cells.

  Patent Document 1 discloses a conventional fuel cell stack. The stack includes a plurality of cells, a plurality of individual cells stacked, a pair of terminals provided at both ends in the stacking direction, a pair of insulators provided outside each terminal, and a pair of ends provided outside these terminals. A plate and a plurality of sets of bolts and nuts for fastening both end plates are provided.

  Each cell includes a separator, a membrane electrode assembly (MEA), and a separator, and adjacent cells share a separator.

  Each membrane electrode assembly includes an electrolyte membrane made of a solid polymer membrane such as Nafion (registered trademark, Nafion (manufactured by Dupon)), a cathode electrode joined to one surface of the electrolyte membrane and supplied with air, and an electrolyte. And an anode electrode which is joined to the other surface of the membrane and supplied with fuel. The cathode and anode are made of carbon particles carrying a catalyst such as platinum (Pt).

  Each separator is laminated with each membrane electrode assembly interposed therebetween, and each separator forms an air chamber on each cathode electrode side and a fuel chamber on each anode electrode side. Each separator is airtightly formed of a conductive material.

In this fuel cell stack, an air chamber and a fuel chamber are formed by the separator and the membrane electrode assembly, and air is supplied to the cathode electrode and fuel is supplied to the anode electrode. During this time, in the membrane electrode assembly, hydrogen ions (H ⁺ ; protons) and electrons are generated from the fuel by an electrochemical reaction at the anode electrode. The proton moves in the form of H ₃ O ⁺ accompanied by water molecules toward the cathode electrode in the electrolyte membrane. Further, electrons flow through the load connected to both terminals and flow to the cathode electrode. On the other hand, in the cathode electrode, water is generated from oxygen, protons and electrons contained in the air. The stack can generate an electromotive force continuously as a result of such electrochemical reactions occurring continuously.

JP 2004-288539 A

  However, in the conventional stack, both end plates are fastened by a plurality of sets of bolts and nuts. In this type of stack, it is necessary to pay attention to the fastening force and the balance at that time so that the electrical resistance between the separator located between both end plates and the cathode electrode and anode electrode of the membrane electrode assembly does not change. For this reason, the conventional stack is increased in size, and for example, mountability on a vehicle or the like has been impaired.

  The present invention has been made in view of the above-described conventional situation, and an object to be solved is to provide a stack that is small in size and excellent in mountability on a vehicle or the like.

  The fuel cell stack of the present invention comprises an electrolyte membrane, a cathode electrode joined to one surface of the electrolyte membrane and supplied with air, and an anode electrode joined to the other surface of the electrolyte membrane and supplied with fuel. A plurality of membrane electrode assemblies having,

  A plurality of separators that are stacked with each membrane electrode assembly sandwiched therebetween, each forming an air chamber on each cathode electrode side, and forming a fuel chamber on each anode electrode side;

  A plurality of individual cells constituted by the separator, the membrane electrode assembly, and the separator are stacked, and a pair of end plates provided at both ends in the stacking direction;

  In a fuel cell stack comprising fastening means for fastening both end plates,

  Each membrane electrode assembly is sandwiched between current collectors made of conductive metal nets or perforated plates, and the current collectors adjacent to each other through the separators are end portions in a direction perpendicular to the stacking direction. The cell is integrated with the separator by individual fixing means so that the cells are in series.

  In this stack, each membrane electrode assembly is sandwiched between conductive metal current collectors, so that the cathode electrode and the anode electrode of each membrane electrode assembly are each energized to the adjacent separator via the current collector. Will be.

  In this stack, the current collectors adjacent to each other via the individual separators are integrated with the separators by the individual fixing means so that the cells are in series at the end in the direction orthogonal to the stacking direction. ing. For this reason, this stack has a strong end in a direction orthogonal to the stacking direction. In particular, this tendency is remarkable because the shape of each membrane electrode assembly is maintained over a long period of time due to the high rigidity of the current collector made of a metal net or a perforated plate.

  For this reason, this stack is unlikely to cause a change in electrical resistance between the separator, the cathode electrode, and the anode electrode without much attention to the fastening force by the fastening means and its balance. The current collector is a net or a perforated plate, so that fuel, protons, or air can be suitably conducted.

  For this reason, a general thing, for example, a volt | bolt and a nut, is employable as a fastening means. Further, it is possible to adopt a small size as a general fastening means and a pair of end plates.

  Therefore, the stack of the present invention can be smaller than the conventional stack capable of the same output. For this reason, this stack | stuck can implement | achieve the outstanding mountability, when mounting in a vehicle etc., for example. In addition, since this stack can employ a small fastening means or the like, it is possible to reduce the weight and the manufacturing cost.

  As the current collector, a conductive metal net or a perforated plate can be employed. Here, the perforated plate refers to a plate in which pores are continuous in the thickness direction and the pores are opened to the outside on both sides in the thickness direction.

  The current collector may be integral with or separate from the cathode and anode electrodes. If the current collector is integrated with the cathode electrode and the anode electrode, the shape of the membrane electrode assembly is easily maintained, and the effects of the present invention are maintained over a long period of time.

  As the fixing means, welding, caulking, or a clip can be employed. If these simple fixing means are adopted, the cost reduction of the stack is remarkable. Although it is slightly less convenient than these, it is also possible to employ bolts and nuts as fixing means.

  Both current collectors are preferably separated from the electrolyte membrane by a gasket in an integrated region. By interposing such a gasket, the end of the stack becomes stronger, and the effects of the present invention become remarkable. Further, if an insulating material is used as the gasket, it is easy to prevent a short circuit between adjacent cells, and a high output can be secured. The gasket may be formed in advance, or may be formed by injection molding or the like when the stack is assembled.

  Each separator is preferably made of a conductive metal. If the separator is made of metal, the effect of the present invention becomes more remarkable due to the high rigidity.

  When at least one of the cathode electrode and the anode electrode is formed on the side opposite to the electrolyte side and has a diffusion layer for diffusing air or fuel, a current collector may be partially exposed in the diffusion layer. preferable. In this case, the current collector is in direct contact with the separator, and the current collecting function is reliably exhibited.

  In at least one of the membrane electrode assembly and the separator, it is preferable that the flat plate material is bent in two dimensions or three dimensions except for the end portions.

  When the membrane electrode assembly is bent, the surface area per projected area of the cathode electrode and the anode electrode is increased, so that the stack generates an electrochemical reaction in a large area per unit volume, and the power generation capacity is increased.

  In addition, when the separator is bent, it is easy to provide a fixing means and a gasket at the end portion, which facilitates manufacture. If each separator obtained by bending a flat plate material in two dimensions or three dimensions is employed, each separator can be easily manufactured as compared with each separator disclosed in Japanese Patent Application Laid-Open No. 4-154007. Inexpensive can also be realized.

  The air chamber is preferably made larger than the fuel chamber. In this case, the stack is less likely to cause a pressure loss of air on the cathode side as the fuel consumption volume increases on the anode side, so that power consumption can be reduced. In addition, since the cross-sectional area of the air chamber in the stack can be made relatively small by increasing it according to the fuel chamber, the stack can be downsized significantly.

  In order to employ a membrane electrode assembly and a separator in which each flat plate is bent in two or three dimensions, and to make the air chamber larger than the fuel chamber, the peaks and valleys of the membrane electrode assembly are formed. It is possible to change the width of the crest and trough of the separator while forming at the same pitch. It is also possible to change the pitch between the peak and valley of the membrane electrode assembly or separator.

Note that how much the air chamber is made larger than the fuel chamber can be set by the number of moles of 2H ₂ + O ₂ → 2H ₂ O, the fuel supply pressure, the air supply pressure, and the oxygen partial pressure in the air. .

  When each of the flat plate materials employs a membrane electrode assembly and a separator bent in two dimensions or three dimensions, the membrane electrode assembly according to the present invention can be obtained by bending the flat plate material of the membrane electrode assembly. The separator according to the present invention is obtained by bending the flat plate material. The bending of the flat plate may be two-dimensional (that is, a corrugated shape in which peaks and valleys are continuous in one direction), or may be three-dimensional (that is, a shape in which peaks and valleys are independently formed without being continuous). . The bending of the flat plate material includes a curve having a gentle bending point or bending line.

  Each separator is preferably formed so as to maintain the shape of the membrane electrode assembly. In this case, the bent shape of the membrane electrode assembly is maintained by the separator, and the effects of the present invention are maintained over a long period of time. Further, if the separator retains the shape of the membrane electrode assembly, it is not necessary to provide a separate shape retainer, and the manufacturing cost can be reduced.

  When each flat plate material employs a membrane electrode assembly and a separator that are bent two-dimensionally or three-dimensionally, it is preferable that the bent membrane electrode assembly or the separator face each other. In this case, the stack can easily resist the pressing force in the stacking direction, and the fastening by the fastening means can be strengthened to ensure a stable output.

  When each plate material employs a membrane electrode assembly and a separator bent in two dimensions or three dimensions, if one membrane electrode assembly and one separator are one unit, one unit of membrane electrode assembly side The rear surface of the valley of one unit may contact the surface of the peak on the separator side of the adjacent unit, or the rear surface of the valley on the side of the membrane electrode assembly of one unit may contact the surface of the valley on the separator side of the adjacent unit .

  Embodiments 1 to 6 embodying the present invention will be described below with reference to the drawings.

  FIG. 1 shows a stack of the first embodiment. The stack includes a plurality of cells 10 (see FIG. 2), a plurality of individual cells 10 stacked, a pair of terminals 11 and 12 provided at both ends in the stacking direction, and a pair provided outside the terminals 11 and 12. Insulators 13 and 14, a pair of end plates 15 and 16 provided on the outside thereof, and a plurality of sets of bolts 17 and nuts 18 for fastening both end plates 15 and 16.

  As shown in FIG. 2, the cell 10 includes a membrane electrode assembly 1 and a pair of separators 2 that sandwich the membrane electrode assembly 1. Each adjacent cell 10 shares the separator 2.

  As shown in FIG. 3, the membrane electrode assembly 1 includes an electrolyte membrane 3, a cathode electrode 4 joined to one surface of the electrolyte membrane 3, and an anode electrode 5 joined to the other surface of the electrolyte membrane 3. . The membrane electrode assembly 1 is formed in a flat plate shape.

  The electrolyte membrane 3 is made of a solid polymer membrane such as Nafion (registered trademark, Nafion (manufactured by Dupon)).

  As shown in FIG. 4, the cathode electrode 4 is formed by a mesh 4a as a current collector, a cathode catalyst layer 4b formed on the electrolyte membrane 3 side of the mesh 4a, and a mesh 4a on the non-electrolyte side. Cathode diffusion layer 4c. The net 4a is made of stainless steel with a corrosion-resistant coating (for example, gold plating). A part of the net 4a is exposed from the cathode diffusion layer 4c. The cathode catalyst layer 4b is a mixture of carbon particles in which a catalyst such as platinum (Pt) is supported on carbon particles and an electrolyte, and the cathode diffusion layer 4c is made of a mixture of carbon particles and PTFE.

  The anode 5 also includes the mesh 5a as a current collector, an anode catalyst layer 5b formed on the electrolyte membrane 3 side of the mesh 5a, and an anode diffusion layer formed by the mesh 5a on the non-electrolyte side. 5c. A part of the net 5a is exposed from the anode diffusion layer 5c. The anode catalyst layer 5b is also a mixture of carbon particles in which a catalyst such as platinum (Pt) is supported on carbon particles and an electrolyte, and the anode diffusion layer 5c is also made of a mixture of carbon particles and PTFE.

  As shown in FIG. 2, the membrane electrode assembly 1 has the anode 5, the electrolyte membrane 3, and the cathode 4 separated from each other at the end in the direction orthogonal to the stacking direction.

  Each separator 2 is obtained by applying a corrosion-resistant coating (for example, gold plating) to stainless steel. These separators 2 are bent in a corrugated shape in which the flat plate material before bending is two-dimensional, that is, isosceles trapezoidal peaks 2a and valleys 2b are continuous in one direction. The separator 2 is formed so that the valley 2b is wider than the mountain 2a. However, each separator 2 is formed in a flat plate shape parallel to the valley 2b at the end in the direction orthogonal to the stacking direction.

  Each cell 10 is configured by sandwiching the membrane electrode assembly 1 by a pair of separators 2. A large number of cells 10 are stacked.

  At this time, each adjacent cell 10 shares the separator 2. Further, the net 4 a exposed from the cathode diffusion layer 4 c and the net 5 a exposed from the anode diffusion layer 5 c are brought into contact with the separator 2. Further, the peaks 2a and valleys 2b of the separators 2 are aligned. Assuming that one membrane electrode assembly 1 and one separator 2 are one unit, this unit has the surface of the membrane electrode assembly 1 in contact with the back surface of the valley 2b of the separator 2, and the back surface of the membrane electrode assembly 1 Has contact with the surface of the crest 2a of the separator 2.

  In particular, the individual cathode electrode 4, the separator 2, and the anode electrode 5 are welded by the welded portion 20 with the separator 2 sandwiched between the end portions in the direction orthogonal to the stacking direction. A pre-molded resin gasket 21 is interposed between each weld 20 and the electrolyte membrane 3. Thus, the cells 10 are connected in series.

  As shown in FIG. 1, the module of the cell 10 thus obtained is sandwiched between a pair of end plates 15 and 16 via a pair of terminals 11 and 12 and a pair of insulators 13 and 14. Thereafter, a plurality of bolts 17 are inserted into both end plates 15 and 16, and nuts 18 are screwed onto the shaft portions of the respective bolts 17. In this way, a stack is obtained.

  In the obtained stack, as shown in FIG. 2, the separator 2 forms the air chamber 6 on the cathode electrode 4 side of the membrane electrode assembly 2 and the fuel chamber 7 on the anode electrode 5 side. . That is, the stack is laminated with a plurality of membrane electrode assemblies 1 and each membrane electrode assembly 1 interposed therebetween, and each stack forms an air chamber 6 on each cathode electrode 4 side, and on each anode electrode 5 side. And a plurality of separators 2 forming a fuel chamber 7.

  In the stack configured as described above, each membrane electrode assembly 1 is sandwiched between the nets 4a and 5a. Therefore, the cathode electrode 4 and the anode electrode 5 of each membrane electrode assembly 1 are respectively connected to the nets 4a and 5a. Then, the adjacent separator 2 is energized.

  In this stack, the two nets 4a and 5a adjacent to each other via the individual separators 2 are separated by the individual welds 20 so that the cells 10 are in series at the end in the direction orthogonal to the stacking direction. 2 and integrated. For this reason, this stack has a strong end in a direction orthogonal to the stacking direction. In particular, this tendency is remarkable because the shape of each membrane electrode assembly 1 is maintained over a long period of time due to the high rigidity of the metal nets 4a and 5a.

  For this reason, this stack is unlikely to cause a change in electrical resistance between the separator 2, the cathode electrode 4, and the anode electrode 5 without paying much attention to the fastening force by the bolt 17 and the nut 18 and the balance thereof.

  Therefore, this stack employs general and small bolts 17 and nuts 18 and can employ relatively thin end plates 15 and 16, which are smaller than the conventional one capable of the same output. Can be. For this reason, this stack | stuck can implement | achieve the outstanding mountability, when mounting in a vehicle etc., for example. In addition, this stack can realize light weight and low manufacturing cost.

  Moreover, in this stack, since both the nets 4a and 5a and the separator 2 are integrated by the simple welding part 20, cost reduction is implement | achieved.

  Furthermore, since this stack has the gasket 20 at the end portion, the end portion becomes stronger, and the effect of the present invention is remarkable. In addition, since an insulating material is used as the gasket 20, it is easy to prevent a short circuit between adjacent cells 10 and a high output can be secured.

  Further, in this stack, since each separator 2 is made of a conductive metal, the effect of the present invention is more remarkable due to the high rigidity.

  Further, in this stack, each separator 2 in which a flat plate material is bent in two dimensions is adopted so that the air chamber 6 is larger than the fuel chamber 7. For this reason, in this stack, it is difficult for air pressure loss to occur on the cathode electrode 4 side as the fuel consumption volume increases on the anode electrode 5 side, so that power consumption can be reduced. In addition, since the cross-sectional area of the air chamber 6 in the stack can be made relatively small by increasing it in accordance with the fuel chamber 7, miniaturization can be realized.

  In addition, since this stack employs each separator 2 in which a flat plate material is bent in two dimensions, each separator 2 can be easily manufactured, and the manufacturing cost can be reduced.

  Further, in this stack, each membrane electrode assembly 1 has nets 4 a and 5 a and is sandwiched between the separators 2. For this reason, the bent shape of the membrane electrode assembly 1 is maintained by the nets 4a and 5a and the separator 2, and the above-described effects are maintained over a long period of time. In particular, since the meshes 4a and 5a and the separator 2 are made of stainless steel and have a corrosion-resistant coating, the shape retention function works for a long time due to high rigidity, and excellent corrosion resistance against acid of the electrolyte membrane 3 Also demonstrates. In addition, since the net | network 4a, 5a has eyes, it is maintained that fuel, a proton, or air is conducted suitably.

  The stack of Example 2 employs the membrane electrode assembly 30 shown in FIG. The membrane electrode assembly 30 includes an electrolyte membrane 3, a cathode electrode 31 joined to one surface of the electrolyte membrane 3, a metal net 32 joined to the non-electrolyte side of the cathode electrode 31, and the electrolyte membrane 3. It consists of an anode electrode 33 bonded to the other surface and a metal net 34 bonded to the non-electrolyte side of the anode electrode 33.

  The cathode electrode 31 includes a gas permeable base material such as carbon cloth, carbon paper, and carbon felt, and a cathode catalyst layer formed on the base material on the electrolyte membrane 3 side and carrying a catalyst such as platinum (Pt). It consists of. The portion other than the cathode catalyst layer in the cathode electrode 31 is constituted by a base material, which is a cathode diffusion layer that diffuses air to the cathode catalyst layer on the non-electrolyte side.

  The anode 33 is also composed of the base material and an anode catalyst layer formed on the base material on the side of the electrolyte membrane 3 and carrying a catalyst. The portion other than the anode catalyst layer in the anode electrode 33 is also constituted by a base material, which is an anode diffusion layer that diffuses air to the anode catalyst layer on the non-electrolyte side.

  A known membrane electrode assembly 35 is formed by the electrolyte membrane 3, the cathode electrode 31 and the anode electrode 33. The nets 32 and 34 as current collectors are joined to the known membrane electrode assembly 35 later. Other configurations are the same as those of the first embodiment.

  In this stack, since the nets 32 and 34 are joined to the known membrane electrode assembly 35 later, the known membrane electrode assembly 35 can be effectively used. Other functions and effects are the same as those of the first embodiment.

  As shown in FIG. 6, the stack of the third embodiment employs a caulking member 40 and a gasket 41, unlike the first and second embodiments.

  In this stack, the anode electrode 5, the separator 2 and the cathode electrode 4 are fixed by a caulking member 40 which is caulked in a state where the anode electrode 5 and the separator 2 are bent so as to wind the cathode electrode 4 at the end. Yes.

  In this stack, the gasket 41 is provided between the caulking members 40 and the electrolyte membrane 3 by performing injection molding at the time of assembly. Other configurations are the same as those of the first embodiment.

  Even in this stack, the same effects as those of the first embodiment can be obtained. In place of the membrane electrode assembly 1, the membrane electrode assembly 30 of Example 2 can also be adopted.

  As shown in FIG. 7, the stack of the fourth embodiment employs a clip 42 having an elastic force in the direction in which the surfaces facing each other close, unlike the first to third embodiments.

  In this stack, the cathode electrode 4, the separator 2, and the anode electrode 5 are fixed by clips 42 at the ends. Other configurations are the same as those of the second embodiment.

  Also in this stack, the same operational effects as in the second embodiment can be obtained. In place of the membrane electrode assembly 1, the membrane electrode assembly 30 of Example 2 can also be adopted.

  As illustrated in FIG. 8, the stack of the fifth embodiment employs a corrugated membrane electrode assembly 36 and a flat plate-shaped separator 37, unlike the first to fourth embodiments.

  As shown in FIG. 9, the membrane electrode assembly 36 has a flat plate material before bending, which is two-dimensional, that is, bent into a corrugated shape in which gentle peaks 36 a and valleys 36 b are continuous in one direction. In the membrane electrode assembly 36, peaks 36a and valleys 36b are formed at the same pitch.

  In this stack, the membrane electrode assemblies 36 are laminated so that the peaks 36 a and the valleys 36 b face each other with the separators 37 interposed therebetween. Note that the air chamber 6 and the fuel chamber 7 are equal in cross-sectional area. Other configurations are the same as those of the first embodiment.

  In this stack, since the membrane electrode assembly 36 in which the flat plate material is bent in two dimensions is adopted, the surface areas per projected area of the cathode electrode 4 and the anode electrode 5 are both large. For this reason, this stack produces an electrochemical reaction in a large area per unit volume, and has a high power generation capacity.

  Further, in this stack, it is easy to counter the pressing force in the stacking direction, and it is easy to secure a stable output by tightening the fastening by the bolt 17 and the nut 18. Other functions and effects are the same as those of the first embodiment. In addition, the membrane electrode assembly which bent the membrane electrode assembly 30 of Example 2 is also employable. In addition, the caulking member 40 of the third embodiment or the clip 42 of the fourth embodiment can be employed instead of the welded portion 20. Furthermore, the gasket 41 of Examples 3 and 4 can also be employed.

  As shown in FIG. 10, the stack of the sixth embodiment employs a corrugated separator 38 unlike the fifth embodiment.

  Each separator 38 is bent into a corrugated plate shape in which the flat plate material before bending is two-dimensional, that is, crests 38a and valleys 38b are continuous in one direction. The separator 38 is formed such that the crest 38a is wider than the trough 38b.

  In this stack, each crest 36a of each membrane electrode assembly 36 and each crest 38a of each separator 38 are aligned, and each valley 36b of each membrane electrode assembly 36 and each trough 38b of each separator 38 are aligned. Yes. Thus, in this stack, each separator 38 holds the shape of the membrane electrode assembly 36.

  When one membrane electrode assembly 36 and one separator 38 are taken as one unit, this unit is configured such that the surface of the crest 36a of the membrane electrode assembly 36 abuts the back surface of the crest 38a of the separator 38, The surface of the valley 36b of 36 has a gap with the back surface of the valley 38b of the separator 38. The back surface, which is the cathode electrode 4 side, of each valley 36 b of each membrane electrode assembly 36 is in contact with the surface of each peak 38 a of each separator 38. Other configurations are the same as those of the fifth embodiment.

  In this stack, since the air chamber 6 is considerably larger than the fuel chamber 7, it is extremely difficult to cause an air pressure loss on the cathode electrode 4 side as the fuel consumption volume increases on the anode electrode 5 side. For this reason, with this stack, power consumption can be considerably reduced.

  In addition, since this stack employs each separator 2 in which a flat plate material is bent in two dimensions, the manufacture of each separator 2 is not so difficult, and the manufacturing cost can be reduced. Other functions and effects are the same as those of the fifth embodiment.

  In the above, the present invention has been described with reference to the first to sixth embodiments. However, the present invention is not limited to the first to sixth embodiments, and can be appropriately modified and applied without departing from the spirit of the present invention. Needless to say.

  For example, a perforated plate can be used instead of the net. The membrane electrode assembly and the separator are not limited to those bent in two dimensions, and may be bent in three dimensions.

  The present invention is applicable to a fuel cell system used for a vehicle or the like.

3 is a plan view of a stack of Example 1. FIG. 3 is an enlarged cross-sectional view of a stack of Example 1. FIG. FIG. 3 is an enlarged cross-sectional view of a membrane electrode assembly according to the stack of Example 1. FIG. 3 is an enlarged cross-sectional view of a membrane electrode assembly according to the stack of Example 1. FIG. 4 is an enlarged cross-sectional view of a membrane electrode assembly according to the stack of Example 2. 6 is an enlarged cross-sectional view of a stack of Example 3. FIG. 10 is an enlarged cross-sectional view of a stack of Example 4. FIG. 10 is an enlarged cross-sectional view of a stack of Example 5. FIG. FIG. 6 is an enlarged cross-sectional view of a membrane electrode assembly according to the stack of Example 5. 10 is an enlarged cross-sectional view of a stack of Example 6. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 3 ... Electrolyte membrane 4, 31 ... Cathode electrode 5, 33 ... Anode electrode 1, 30, 36 ... Membrane electrode assembly 6 ... Air chamber 7 ... Fuel chamber 2, 37, 38 ... Separator 10 ... Cell 15, 16 ... End plate 17, 18 ... Fastening means (17 ... bolt, 18 ... nut)
4a, 4b, 32, 34 ... net, current collector 20, 40, 42 ... fixing means (20 ... weld, 40 ... caulking member, 42 ... clip)
21 ... Gasket 4c ... Cathode diffusion layer 5c ... Anode diffusion layer 2a, 36a, 38a ... Mountain

Claims (10)

A plurality of membrane electrode assemblies having an electrolyte membrane, a cathode electrode joined to one surface of the electrolyte membrane and supplied with air, and an anode electrode joined to the other surface of the electrolyte membrane and supplied with fuel;
A plurality of separators that are stacked with each membrane electrode assembly sandwiched therebetween, each forming an air chamber on each cathode electrode side, and forming a fuel chamber on each anode electrode side;
A plurality of individual cells constituted by the separator, the membrane electrode assembly, and the separator are stacked, and a pair of end plates provided at both ends in the stacking direction;
In a fuel cell stack comprising fastening means for fastening both end plates,
Each membrane electrode assembly is sandwiched between current collectors made of a conductive metal mesh or a perforated plate, and both current collectors adjacent to each other through the separators are end portions in a direction perpendicular to the stacking direction. A fuel cell stack, wherein the cells are integrated with the separator by individual fixing means so that the cells are in series.   2. The fuel cell stack according to claim 1, wherein the fixing means is welding, caulking, or a clip.   3. The fuel cell stack according to claim 1, wherein the current collectors are separated from the electrolyte membrane by a gasket in an integrated region. 4.   4. The fuel cell stack according to claim 3, wherein the gasket is insulative.   5. The fuel cell stack according to claim 1, wherein each of the separators is made of a conductive metal. At least one of the cathode electrode and the anode electrode has a diffusion layer formed on the side opposite to the electrolyte side and diffusing the air or the fuel,
6. The fuel cell stack according to claim 1, wherein the current collector is partially exposed in the diffusion layer.   The fuel cell stack according to any one of claims 1 to 6, wherein at least one of the membrane electrode assembly and the separator has a flat plate bent in two dimensions or three dimensions except for the end portion.   The fuel cell stack according to claim 7, wherein the air chamber is larger than the fuel chamber.   The fuel cell stack according to claim 7 or 8, wherein each separator is formed so as to maintain the shape of the membrane electrode assembly.   10. The fuel cell stack according to claim 7, wherein the bent membrane electrode assembly or the separator has crests facing each other. 11.

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