JP2006073398A - Fuel cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel cell of which manufacturing cost is low and improvement of performance demanded for a separator is achieved. <P>SOLUTION: The separator 29 is constituted by overlaying a partition plate 100 composed of conductive metal plate provided with a power generation/current collecting part 2 having a plurality of formed holes 3, and longitudinal walls 7 and bottom walls 10 formed between the respective holes 3, and a receiving plate 101 composed of the conductive metal plate provided with a housing part 19 which houses the power generation/current collecting part 2 of that partition plate 100. Unit cells 37 are constituted by arranging those separators 29 respectively at both sides of an MEA 33 so that the partition plate 100 is contacted with the MEA 33, the plurality of unit cells 37 are laminated so that the receiving plates 101 of the separator 29 are mutually contacted, and by caulking-joining brim ends of the receiving plates 101 contacted with each other, all the unit cells 37 are integrally fixed at that state. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a fuel cell configured by stacking a plurality of unit cells each including a separator made of a conductive metal plate.

  A fuel cell is a battery that directly converts chemical energy into electric energy, and is being put to practical use in various fields such as a power source or power source of a vehicle such as an electric vehicle or a generator for a house. . In particular, the polymer electrolyte fuel cell (PEFC) operates at a lower temperature than other fuel cell systems and has a high output density, so that it is expected to be applied as a power source for automobiles and portables.

  Such a polymer electrolyte fuel cell obtains a necessary voltage from a “unit cell” composed of MEA (Membrane Electrolyte Assembly) and separators disposed on both sides of the MEA. As many as possible are stacked to form a stack.

  The separator mainly has a role of forming a flow path for supplying fuel (hydrogen and air or oxygen (hereinafter simply referred to as air)) to the MEA, and a role of collecting generated electricity in contact with the MEA. have.

  Here, fuel cell separators currently being developed can be roughly divided into the following three types.

  1) Metal thin plate separator: A metal plate is bent into a concavo-convex shape by pressing or the like to form a fuel flow path and a current collector (see Patent Documents 1 and 2).

  2) Resin separator: A fuel channel and a current collecting part formed by cutting a plate material formed by solidifying graphite powder with a thermosetting resin binder or the like (see Patent Document 3).

  3) Carbon separator: A fuel separator and a current collector formed by cutting a plate made of a high-strength carbon material.

JP-A-10-302814 JP 2001-325969 A JP-A-8-162131

  However, each of these separators has the following problems.

  1) Problems of the thin metal plate separator: Since the corners of the convex portions forming the current collecting portion have an R shape, the current collecting efficiency is poor. The shape is complex and difficult to manufacture.

  2) Problems of resin separator: Manufacturing cost is high. Thinning is difficult. Low strength compared to metal. If the graphite content is increased in order to increase the electrical conductivity, the moldability is deteriorated.

  3) Problem of carbon separator: production cost is high. Thinning is difficult. Low strength compared to metal.

  Accordingly, an object of the present invention is to solve the above-described problems, and to provide a fuel cell including a separator with low manufacturing cost and high current collection efficiency.

  In order to achieve the above object, the present invention provides a partition plate made of a conductive metal plate having a plurality of holes, and a power generation / current collection unit having a vertical wall and a bottom wall formed between the holes. A separator is formed by superimposing a receiving plate made of a conductive metal plate provided with an accommodating portion for accommodating the power generation / collecting portion of the partition plate, and the separator is brought into contact with the MEA. The unit cells are arranged on both sides of the MEA, and a plurality of unit cells are laminated so that the separator receiving plates are in contact with each other, and the edges of the receiving plates that are in contact with each other are caulked and joined together. In this state, all unit cells are integrally fixed.

  Here, when the receiving plate has a protruding portion that partially protrudes toward the partition plate and a plurality of the unit cells are stacked, a coolant flow path is formed between the protruding portions of the receiving plate that are in contact with each other. In addition, the coolant flow path may be stopped by caulking and joining the edges of the backing plate.

  The height of the caulking joint at the edge of the backing plate may be set to be equal to or greater than the distance between the backing plate of one separator and the backing plate of the other separator in each unit cell.

  The rising angle of the edge of the backing plate with respect to the surface of the backing plate is set at an acute angle or an obtuse angle with respect to the surface of the backing plate, and when the unit cells are integrally fixed, The unit cells may be elastically deformed and brought into close contact with each other by the elastic force.

  Further, a hole for supplying or discharging fuel may be formed in the receiving plate, and edges of the holes of the receiving plate that are in contact with each other may be caulked and joined.

  In addition, a hole for supplying or discharging fuel is formed in the partition plate, and in addition to the edge of the hole for supplying or discharging fuel in the receiving plates that are in contact with each other, either or both receiving plates are provided. The edges of the overlapping holes for supplying or discharging the fuel may be joined by caulking.

  According to the present invention, the following effects can be obtained.

  1) Since the separator is composed of two metal plates (partition plate and receiving plate), the shape of each metal plate can be simplified. As a result, the corners of the current collector can be sharpened, and high current collection efficiency can be obtained.

  2) Since the separator which piled up the conductive metal plate is used, the manufacturing cost is low compared with the resin separator and the carbon separator. In addition, it is thinner and stronger than resin separators and carbon separators.

  3) Since the receiving plates of adjacent unit cells are fixed by caulking and joining, they can be manufactured easily and inexpensively. Moreover, the electrical conductivity between unit cells can be ensured.

  Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

  First, the structure of the fuel cell which is the premise of the present embodiment will be described. The basic structure of this fuel cell is described in the specification of Japanese Patent Application No. 2004-54719 filed earlier by the present applicant (not disclosed at the time of filing of the present application and does not constitute the prior art). It is the same as that.

  The fuel cell of this embodiment is a polymer electrolyte fuel cell, and its separator is characterized in that it is configured by overlapping two members (partition plate and receiving plate) made of a conductive metal plate.

  The separator used for the fuel cell of this embodiment will be described with reference to FIGS. 1 and 2. FIG. 1 is a front view of a member called a partition plate among members constituting the separator, and FIG. 2 is a front view of a member called a backing plate.

  As shown in FIG. 1, the partition plate 100 is formed of a press-formed product of a conductive metal plate (for example, stainless steel having a thickness of 0.2 mm or less), and includes a plurality of components necessary for configuring a unit cell or a fuel cell ( Here, three pieces are formed at intervals. Here, they are referred to as a first component 100a, a second component 100b, and a third component 100c, respectively, from the left side in the figure. These components 100a, 100b, and 100c all have the same structure.

  As shown in FIG. 2, the receiving plate 101 is also made of a press-formed product of a conductive metal plate (for example, stainless steel having a thickness of 0.2 mm or less), and a plurality of components necessary for configuring a unit cell or a fuel cell ( Here, three pieces are formed at intervals. Here, they are referred to as the first component 101a, the second component 101b, and the third component 101c, respectively, from the left side in the figure. These constituent elements 101a, 101b, and 101c all have the same structure.

  By overlapping and joining the partition plate 100 and the receiving plate 101, the first component 100a, the second component 100b, and the third component 100c of the partition plate 100 are respectively the first component of the receiving plate 101. In cooperation with 101a, the second component 101b, and the third component 101c, three elements that perform a necessary function as a separator are arranged side by side.

  A specific structure of the constituent elements 100a, 100b, and 100c of the partition plate 100 will be described with reference to FIGS. In the following description, only the first component 100a will be described as a representative of the components 100a, 100b, and 100c.

  3 is an enlarged front view of the first component 100a, FIG. 4 is an enlarged view of a portion A in FIG. 3, and FIG. 5 is a sectional view taken along line VV in FIG. FIG. 4 shows a state where the portion A of FIG. 3 is rotated by approximately 90 °.

  As shown in the figure, the power generation / collection unit 2 is formed in the substantially central portion of the first component 100a of the partition plate 100. The power generation / collection unit 2 extends in a direction substantially orthogonal to the side edge 1a of the partition plate 100, and is spaced at a predetermined interval in a direction (vertical direction in FIG. 3) substantially orthogonal to the upper and lower edges 1b of the partition plate 100. A plurality of elongated holes 3 arranged in parallel. A circular hole 5 having a diameter larger than the width of the long hole 3 is formed at both ends in the longitudinal direction (left and right direction in FIG. 3) of each long hole 3, and one side of the circular hole 5 (FIG. 4). A notch 6 that extends a predetermined distance in the longitudinal direction of the long hole 3 is continuously formed in the middle left). The notches 6 are formed on different side portions at both ends of the single long hole 3. That is, in FIG. 3, a notch 6 is formed in the lower part at the left end of each elongated hole 3 and in the upper part at the right end.

  As can be seen from FIGS. 4 and 5, the vertical walls 7 bent at an angle of approximately 90 ° with respect to the surface of the partition plate 100 are formed on both sides of each slot 3. As described above, since the notch 6 is formed on one side (left side in FIG. 4) of the end portion of the long hole 3, the end positions k1 and k2 of the vertical wall 7 located on both sides of the long hole 3. Differ every other line (see FIG. 4).

  A groove 9 (see FIGS. 4 and 5) is formed in a space defined by each elongated hole 3 and a vertical wall 7 positioned on both sides of the elongated hole 3. Further, a cross wall 11 having a substantially U-shaped cross section is formed by a bottom wall 10 positioned between two adjacent elongated holes 3 and 3 and two vertical walls 7 positioned on both sides of the bottom wall 10. That is, the power generation / collection unit 2 includes the grooves 9 and the crosspieces 11 that are alternately formed along a direction (vertical direction in FIG. 3) substantially orthogonal to the upper and lower edges 1 b of the partition plate 100.

  The groove 9 functions as a fuel flow path for bringing fuel (hydrogen or air) into contact with an electrode of an MEA (not shown), and can also be called a power generation unit. On the other hand, the crosspiece 11 functions as a fuel flow path, and functions as a current collector that collects electrons generated when the bottom wall 10 comes into contact with the MEA.

  Such grooves 9 and crosspieces 11 can be formed by pressing a conductive metal thin plate. For example, after punching the circular hole 5 and the notch 6 in a thin metal plate by piercing, a slit is formed along the center in the width direction of the elongated hole 3 to be formed, and the elongated hole 5 and the notch positioned above and below are formed. 6 is connected with a slit. Then, the part located in the both sides of a slit is bent, and the vertical wall 7 and the long hole 3 are formed. Lastly, re-striking is performed to make the corner R of the bottom wall 10 and the vertical wall 7 sharp (edge). By such a process, the groove 9 and the crosspiece 11 can be formed.

  In the present embodiment, the cross-sectional area of the groove 9 and the crosspiece 11 is constant over the entire longitudinal direction, and the cross-sectional area of the groove 9 and the cross-sectional area of the crosspiece 11 are equal to each other. It is formed. By doing so, the flow velocity of the fuel flowing in the groove 9 and the crosspiece 11 can be made almost constant at all positions. Here, assuming that the height of the vertical wall 7 (depth of the groove 9) is h and the thickness of the partition plate 1 is t, the width w1 of the groove 9 is represented by w1 = 2 (ht−C). Can do. C is a coefficient that takes into account the material surplus of the bending R portion. And the cross-sectional area (= w1 × h) of the groove 9 and the cross-sectional area (= (w2-2t) × (ht)) in the crosspiece 11 of the crosspiece 11 necessary to make the same. The width W2 is w2 = {h · w1 / (ht)} + 2t. Thus, the widths w1 and w2 of the groove 9 and the crosspiece 11 are determined based on the height h of the vertical wall 7, the plate thickness t of the partition plate 1, and the like.

  Now, as shown in FIG. 3, in the first component 100 a of the partition plate 100, a flat flange portion 12 is formed at a portion outside the power generation / collection unit 2. The flange portion 12 serves to prevent the fuel supplied to the power generation / current collection portion 2 (the groove 9 and the crosspiece 11) from leaking to the outside when a receiving plate 101 and a partition plate 100 described later are joined. Fulfill. First to fourth fuel supply / discharge holes 13a, 13b, 15a, 15b are formed in the flange portion 12, respectively. The first fuel supply / discharge hole 13a and the second fuel supply / discharge hole 13b, and the third fuel supply / discharge hole 15a and the fourth fuel supply / discharge hole 15b are respectively located with respect to the central portion of the first component 100a. To the target (so as to face diagonally across the power generation / collection unit 2). Further, the first fuel supply / discharge hole 13a and the third fuel supply / discharge hole 15a are arranged at the upper part of the power generation / collection unit 2, and the second fuel supply / discharge hole 13b and the fourth fuel supply / discharge hole 15b are It is arranged at the lower part of the power generation / collection unit 2. Furthermore, coolant supply / discharge holes 16 a and 16 b are formed in the flange portion 12. The coolant supply / discharge holes 16a and 16b are arranged so as to straddle the power generation / collection unit 2 in the vertical direction in the drawing.

  The above is the structure of the first component 100a. In the partition plate 100 of this embodiment, three components similar to the first component 100a are arranged in parallel. As can be seen from FIG. 1, the flange portion 12 is shared by adjacent portions of the constituent elements 100a, 100b, and 100c. By doing so, the interval between the constituent elements 100a, 100b, 100c can be reduced, and the length of the partition plate 100 (the length in the left-right direction in FIG. 1) can be shortened.

  Next, the structure of the backing plate 101 will be described with reference to FIGS. In the following description, only the first component 101a will be described as a representative of the components 101a, 101b, and 101c.

  6 is an enlarged front view of the first component 101a of the backing plate 101, FIG. 7A is a sectional view taken along line VIIa-VIIa in FIG. 6, and FIG. 7B is a sectional view taken along line VIIb-VIIb in FIG. 7 (c) is a sectional view taken along line VIIc-VIIc in FIG. In FIG. 6, a line indicated by a two-dot chain line indicates a bending (bending) line of the receiving plate 101.

  As shown in the figure, an accommodating portion 19 for accommodating the power generation / current collecting portion 2 of the first component 100a of the partition plate 100 is formed at substantially the center of the first component 101a of the receiving plate 101. The accommodating part 19 has a substantially rectangular shape, and when it is overlapped with another separator, a convex part 20 for forming a coolant flow path is formed between the accommodating part 19 and outside the convex part 20. A flat flange portion 21 is formed. As can be seen from FIG. 7, the flange portion 21 and the accommodating portion 19 are located on substantially the same plane, and the convex portion 20 protrudes from the surfaces of the flange portion 21 and the accommodating portion 19. As shown in FIG. 6, the convex portion 20 is formed so as to surround the accommodating portion 19. That is, the accommodating part 19 is formed in the area | region inside the convex part 20, and the flange part 21 is each formed in the area | region outside. The height d of the accommodating portion 19, in other words, the depth d (see FIG. 7B) of the convex portion 20 is determined from the height h (see FIG. 5) of the vertical wall 7 of the partition plate 1. It is set to be approximately equal to the dimension (ht) obtained by subtracting the thickness t.

  The first component 101a of the receiving plate 101 further includes first and second communication holes 22a and 22b and first and second isolation holes 23a and 23b. The communication holes 22a and 22b and the isolation holes 23a and 23b are holes for supplying or discharging fuel. When the partition plate 100 and the receiving plate 101 are overlapped, the first component 100a of the partition plate 100 is used. The first to fourth fuel supply / discharge holes 13a, 13b, 15a, 15b are aligned.

  The first component 101a of the receiving plate 101 has a projecting portion 25 that is continuous with a part of the housing portion 19 and is located on the same plane as the housing portion 19, and has first and second communication holes. 22 a and 22 b are formed in the overhang portion 25. Accordingly, the fuel (hydrogen or air) supplied from one of the first and second communication holes 22a and 22b flows to the accommodating portion 19 through the overhang portion 25 and passes through the other overhang portion 25 to the first. And it will be discharged | emitted from the other of 2nd communicating holes 22a and 22b.

  On the other hand, the first and second isolation holes 23 a and 23 b are formed in the isolation part 26 surrounded by the convex part 20, although the first and second isolation holes 23 a and 23 b are located on substantially the same plane as the accommodating part 19. Therefore, the fuel (air or hydrogen) supplied from the first and second separation holes 23 a and 23 b flows out in the thickness direction of the receiving plate 101 without flowing into the accommodating portion 19.

  Cooling liquid supply / discharge holes 27 a and 27 b are formed in the convex portion 20. The coolant supply / discharge holes 27a, 27b are aligned with the coolant supply / discharge holes 16a, 16b of the first component 100a of the partition plate 100 when the partition plate 100 and the receiving plate 101 are overlapped.

  The above is the structure of the first component 101a. The receiving plate 101 of the present embodiment is provided with three similar components to the first component 101a. As can be seen from FIG. 2, the convex portion 20 is shared by the adjacent portions of the constituent elements 101 a, 101 b, and 101 c, and the flange portion 21 includes the accommodating portions 19 and convex portions 20 of all the constituent elements 101 a, 101 b, and 101 c. It is formed in an annular shape so as to surround it. By doing so, the interval between the constituent elements 101a, 101b, 101c can be narrowed, and the length of the receiving plate 101 (the length in the left-right direction in FIG. 2) can be shortened.

  The partition plate 100 and the receiving plate 101 described above are preferably subjected to a surface treatment such as metal plating for the purpose of preventing generation of an oxide film, preventing corrosion, preventing elution of metal ions, and imparting water repellency. However, at present, the development of metal materials is proceeding at a rapid pace. Therefore, if a material having the above-described characteristics is developed, of course, the surface treatment is unnecessary.

  Next, a separator formed by superposing the partition plate 100 and the receiving plate 101 will be described with reference to FIGS. FIG. 8 is a front perspective view showing an overlapping portion of the first component 100a of the partition plate 100 and the first component 101a of the receiving plate 101, and FIG. 9 is a cross-sectional view taken along line IX-IX in FIG. .

  As shown in the figure, the partition plate 100 and the receiving plate 101 are overlapped in a state where the front end portion (the end portion opposite to the bottom wall 10) of the vertical wall 7 of the partition plate 100 faces the receiving plate 101 side. The separator 29 is configured. At this time, the power generation / collection unit 2 of each component 100a, 100b, 100c of the partition plate 100 is received in the storage unit 19 of each component 101a, 101b, 101c of the plate 101. As described above, since the depth d of the receiving portion 19 of the receiving plate 101 is equal to the dimension obtained by subtracting the plate thickness t from the height h of the vertical wall 7 of the partition plate 100, the distal end portion of the vertical wall 7 is the receiving portion. When contacted with 19, the flange portion 12 of the partition plate 100 and the convex portion 20 of the receiving plate 101 come into contact (that is, the convex portion 20 of the receiving plate 101 protrudes toward the partition plate 100). By joining the flange part 12 and the convex part 20 in this state, the circumference | surroundings of the electric power generation and current collection part 2 (accommodating part 19) can be sealed over the whole region, and it can prevent that a fuel leaks outside. Further, as shown in FIG. 8, the outer end k <b> 1 of the vertical wall 7 of the partition plate 100 contacts the left and right side walls 19 a of the housing portion 19. As a result, a plurality of fuel flow paths 30 defined by the vertical walls 7 are formed in the accommodating portion 19. More specifically, the fuel flow path 30 includes a flow path 30a formed by the groove 9 of the partition plate 100 and a flow path 30b formed in the crosspiece 11, and these flow paths 30a and 30b are in the vertical direction. Are alternately formed.

  As can be seen from FIG. 8 and FIG. 4, the inner end k2 of the vertical wall 7 does not come into contact with the side wall 19a of the accommodating part 19, so that a gap is formed between the side wall 19a of the accommodating part 19 and the inner end k2. The Adjacent fuel flow paths 30 communicate with each other through this gap. This gap is formed alternately at the left and right ends of each fuel flow path 30.

  As shown in FIGS. 8 and 9, when the partition plate 100 and the receiving plate 101 are overlapped, the first fuel supply / discharge hole 13 a of the partition plate 100, the first series of through holes 22 a of the receiving plate 101, and the partition plate 100. The second fuel supply / discharge hole 13b and the second communication hole 22b of the receiving plate 101, the third fuel supply / discharge hole 15a of the partition plate 100, the first isolation hole 23a of the receiving plate 101, and the fourth fuel of the partition plate 100. The supply / discharge hole 15b and the second separation hole 23b of the receiving plate 101 are aligned. Further, in the space defined by the flange portion 12 of the partition plate 100 and the overhang portion 25 of the receiving plate 101, the first fuel supply / discharge hole 13a and the first series of through holes 22a and the accommodating portion 19 (power generation / collection) are provided. A communication passage 31 that communicates with the electric part 2) and a communication passage 32 that communicates the housing part 19 with the second fuel supply / discharge hole 13b and the second communication hole 22b are formed.

  In this way, by separating the partition plate 100 and the receiving plate 101, a separator having a plurality (three in this case) of power generation / collection units 2 is formed. In this embodiment, the partition plate 100 and the receiving plate 101 are joined by an adhesive having conductivity. However, the present invention is not limited in this respect, and other means such as welding may be used.

  Here, the present applicant has found that the rigidity of the partition plate 100 is preferably larger than that of the plate 101 by making the plate thickness of the partition plate 100 larger than the plate thickness of the plate 101. This is related to the fact that the receiving plate 101 has a more complicated shape than the partition plate 100, and molding distortion is likely to occur. In other words, by making the rigidity of the partition plate 100 larger than that of the receiving plate 101, when the partition plate 100 and the receiving plate 101 are overlapped and joined, the receiving plate 101 is easily adapted to the shape of the partition plate 100. It becomes possible to absorb the molding strain and properly overlap. In addition, there is also an advantage that the sealing performance of the fuel flow path 30 and the like is improved by the spring effect by leaving a little molding distortion of the receiving plate 101.

  Next, the structure of the parallel unit cell configured using the separator 29 described above will be described with reference to FIGS. 10 and 11. FIG. 10 is a development view of one unit cell (unit cell constituted by the first components 100a and 101a of the partition plate 100 and the receiving plate 101) among the parallel type unit cells, and FIG. It is sectional drawing along the XI line. FIG. 11 is not a development view, but shows a state where all of the partition plates 100-1 and 100-2, the receiving plates 101-1 and 101-2, and the MEA 33 in FIG. 10 are joined. Also in the following description, only the part comprised by the 1st components 100a and 101a of the partition plate 100 and the receiving plate 101 is demonstrated.

  Now, as shown in FIGS. 10 and 11, unit cells 37 are formed by disposing separators 29-1 and 29-2 on both sides of the MEA 33. At this time, the separators 29-1 and 29-2 are arranged such that the bottom walls 10 of the partition plates 100-1 and 100-2 are in contact with the electrodes on the side surfaces of the MEA 33.

  More specifically, in FIG. 10 and FIG. 11, the separator 29-1 positioned above the MEA 33 is arranged so that the receiving plate 101-1 is positioned upward and the partition plate 100-1 is positioned downward. It arrange | positions so that the vertical wall 7 of the board 100-1 may extend toward upper direction.

  On the other hand, the separator 29-2 located on the lower side of the MEA 33 is disposed in a state where the upper separator 29-1 is reversed in the left-right direction in FIG. That is, the lower separator 29-2 is arranged such that the receiving plate 101-2 is positioned downward and the partition plate 100-2 is positioned upward, that is, the vertical wall 7 of the partition plate 100-2 is directed downward. It is arranged to extend.

  Thus, by arranging the two separators 29-1 and 29-2 so that the partition plates 100-1 and 100-2 face each other across the MEA 33, the partition plates of both separators 29-1 and 29-2. The bottom walls 10 of 100-1 and 100-2 are in contact with the side surfaces of the MEA 33, respectively. As a result, as shown in FIG. 11, the openings of the grooves 9 (fuel flow paths 30 a) of the partition plates 100-1 and 100-2 are covered with the side surfaces of the MEA 33.

  When the two separators 29-1 and 29-2 are arranged on both sides of the MEA 33, as shown in FIG. 10, the first series of through holes 22a and the first fuel supply / discharge of one separator 29-1 (upper side in the figure). The hole 13a (the hole communicated with the power generation / collection unit 2 by the communication passage 31), the fourth fuel supply / discharge hole 15b and the second separation hole 23b (convex) of the other (lower side in the figure) separator 29-2. The holes separated from the power generation / collection unit 2 by the unit 20 are aligned. Similarly, the second communication hole 22b and the second fuel supply / discharge hole 13b of one separator 29-1 are aligned with the third fuel supply / discharge hole 15a and the first isolation hole 23a of the other separator 29-2. The first separation hole 23a and the third fuel supply / discharge hole 15a of one separator 29-1 are aligned with the second fuel supply / discharge hole 13b and the second communication hole 22b of the other separator 29-2. The second separation hole 23b and the fourth fuel supply / discharge hole 15b of the separator 29-1 are aligned with the first fuel supply / discharge hole 13a and the first series of through holes 22a of the other separator 29-2.

  In this parallel unit cell 37, both fuels (hydrogen and air) are supplied from the first through hole 22a and the first isolation hole 23a of the receiving plate 101-1 of one separator 29-1.

  One fuel (in this case, hydrogen) supplied from the first series of through holes 22a flows through the communication passage 31 to the power generation / collection unit 2 side of the separator 29-1, and passes through each fuel passage 30. Flowing. Hydrogen flows in the longitudinal direction of the fuel flow path 30 and flows into the adjacent fuel flow path 30 from the gap described above at the end thereof, and flows in the reverse direction in the fuel flow path 30 (see FIG. 4). That is, hydrogen flows by alternately turning back the fuel flow path 30 a formed by the groove 9 and the fuel flow path 30 b formed by the crosspiece 11. At this time, the direction of hydrogen flowing in the fuel flow path 30a formed by the groove 9 is the same in all the flow paths 30a, and the direction of hydrogen flowing in the fuel flow path 30b formed by the crosspiece 11 is also in all the flow paths 30b. It will be the same.

  Hydrogen flowing in the fuel flow path 30 a formed by the groove 9 contacts one side (negative electrode) of the MEA 33 and contributes to power generation, and hydrogen flowing in the crosspiece 11 does not contact the MEA 33. This is because this region is a region for collecting generated electricity by the crosspiece 11 (bottom wall 10). The fuel that has flowed through the fuel flow path 30 flows into the second fuel supply / discharge hole 13b of the partition plate 100-1 through the communication path 32, the hole 35 formed in the MEA 33, and the partition of the other separator 29-2. It is discharged in the thickness direction through the third fuel supply / discharge hole 15a of the plate 100-2 and the first isolation hole 23a of the receiving plate 101-2.

  In addition, a part of the hydrogen supplied from the first through hole 22a of the receiving plate 101-1 of the separator 29-1 is a hole formed in the first fuel supply / discharge hole 13a and the MEA 33 of the partition plate 100-1. 35, flows to the other separator 29-2, and flows out from the fourth fuel supply / discharge hole 15b and the second separation hole 23b in the thickness direction.

  On the other hand, the fuel (in this case, air) supplied from the second separation hole 23a of the receiving plate 101-1 of the upper separator 29-1 does not flow to the power generation / collection unit 2 side of the separator 29-1, It flows through the third fuel supply / discharge hole 15a of the partition plate 100-1 and the hole 35 formed in the MEA 33 to the second fuel supply / discharge hole 13b of the partition plate 100-2 of the lower separator 29-2. . Part of the air that has flowed into the second fuel supply / discharge hole 13b flows through the communication passage 32 to the power generation / collection unit 2 (fuel flow path 30), and the other side of the MEA 33 ( Contact the positive electrode) to contribute to power generation. After that, it is discharged in the thickness direction from the first through hole 22a of the receiving plate 101-2 through the communication passage 31. Further, part of the air that has flowed into the second fuel supply / discharge hole 13b of the partition plate 100-2 flows out in the thickness direction through the second communication hole 22b of the receiving plate 101-2.

  The above is the unit structure of the unit cell, and by arranging the separator 29 composed of the partition plate 100 and the receiving plate 101 of this embodiment on both sides of the MEA 33, three unit cells having the same structure are arranged side by side. .

  Now, the fuel cell of the present embodiment configured by stacking a plurality of the parallel unit cells will be described with reference to FIGS. 12 and 13. Also in the following description, only the part comprised by the 1st components 100a and 101a of the partition plate 100 and the receiving plate 101 is demonstrated.

  12 is a partial side cross-sectional view of the fuel cell, and FIG. 13 is an enlarged view of a portion B in FIG.

  In this fuel cell 36, a plurality of unit cells 37 similar to those shown in FIGS. 10 and 11 are stacked such that the receiving plates 101 of the separators 29 of each unit cell 37 are in contact with each other. A separator 29 'for forming a coolant flow path and a pressing plate 39 are arranged on the upper and lower end surfaces, and the unit cell 37, the separator 29' and the pressing plate 39 are integrally fixed by bolts.

  In this fuel cell 36, the supply is made from the first series of through holes 22a of the upper separator 29 of the unit cell 37 located at the uppermost part through the holes formed in the holding plate 39 and the separator 29 'for forming the coolant flow path. The fuel (herein referred to as hydrogen) flows through the communication passage 31 of the separator 29 to the power generation / collection unit 2 and contributes to power generation, and is thickened from the second fuel supply / discharge hole 13b of the partition plate 100. It is discharged in the direction. Further, a part of the hydrogen supplied from the first series of through holes 22a is adjacent through the hole 35 of the MEA 33, the third fuel supply / discharge hole 15b of the lower separator 29, and the second isolation hole 23b ( It flows to the first series of through holes 22a of the upper separator 29 of the lower unit cell 37. Then, it flows to the power generation / collection unit 2 through the communication passage 31 of the separator 29. That is, hydrogen is supplied only to the power generation / collection unit 2 of the upper separators 29 of all the unit cells 37 (the separators 29 disposed on the negative electrode side of the MEA 33).

  On the other hand, the air supplied from the first isolation holes 23a of the upper separators 29 of the unit cells 37 located at the top is the lower separators 29 of all the unit cells 33 (the separators 29 arranged on the positive electrode side of the MEA 33). Is supplied only to the power generation / collection unit 2.

  As a result, hydrogen is supplied to the negative electrodes of the MEAs 33 of all the unit cells 37 and air is supplied to the positive electrodes, and power generation is performed. The electricity generated in each unit cell 37 is collected by the current collector (crosspiece 11) of the separator 29 and taken out to the outside. Further, the electrical connection (connection) between the adjacent unit cells 37 is such that the receiving plates 101 of the separators 29 in the adjacent unit cells 37 are in contact with each other on the back surface (the surface opposite to the side facing the partition plate 100). Secured by More specifically, as shown in FIG. 13, the separation portion 26 of one receiving plate 101 and the projecting portion 25 of the other receiving plate 101 come into contact with each other.

  In the fuel cell 36, the coolant flow path 40 is formed between the two separators 29 (29 ′) that are joined one above the other. The coolant channel 40 is formed between the convex portions 20 of the receiving plate 101 of the separator 29 (29 ′) and between the convex portion 20 and the overhang portion 25. The coolant supplied from one of the coolant supply / discharge holes 27a, 16a and the coolant supply / discharge holes 27b, 16b (see FIG. 10) of each separator 29 extends along the coolant channel 40 (convex portion 20). The separator 29 flows around the power generation / collection unit 2 and is discharged from the other of the coolant supply / discharge holes 27b, 16b and the coolant supply / discharge holes 27a, 16a.

  As shown in FIG. 13, a spacer 41 is interposed between the end edge (flange portion 12) of the partition plate 100 and the end edge (flange portion 21) of the receiving plate 101 in each separator 29. By providing the spacer 41, when the unit cells 37 are tightened together, the separator 29 (partition plate 100 and receiving plate 101) and the MEA 33 can be tightened with a uniform surface pressure, and stress concentration can be prevented.

  The above is the single structure of the fuel cell, and by stacking unit cells using the separator 29 composed of the partition plate 100 and the receiving plate 101 of this embodiment, three fuel cells having the same structure are arranged side by side. The It is possible to take out the power independently from each fuel cell or to take out the power of all the fuel cells collectively.

  For example, when the fuel cell is mounted on a vehicle or the like, the fuel flow path 30 of each separator 29 extends in the horizontal direction (lateral direction), and the hole for supplying fuel is positioned at the top. Therefore, the supplied fuel flows in the fuel flow path 30 of the separator 29 of each unit cell 37 in the lateral direction and from the upper stage to the lower stage.

  According to the fuel cell of the present embodiment, the following effects can be obtained.

  1) Since the separator 29 is divided into the partition plate 100 and the receiving plate 101, the shape of the partition plate 100 and the receiving plate 101 can be made simpler than the conventional metal thin plate separator. As a result, the corner of the current collector, that is, the corner R between the vertical wall 7 and the bottom wall 10 can be sharpened, and high current collection efficiency can be obtained.

  2) Since the shape of the partition plate 100 and the receiving plate 101 is simple, the manufacturing is easy and the manufacturing cost is low.

  3) Since it is a press-molded product of a thin metal plate, it can be made thinner than resin and carbon separators. For example, even the thinnest resin separator currently developed is about 2 mm, but in the separator of this embodiment, it can be easily made 1 mm or less.

  4) Since the coolant flows annularly around the power generation / collection unit 2, heat generated by power generation can be effectively absorbed, and the temperature rise suppression effect is high.

  5) Since the coolant flow path 40 is formed between the receiving plates 101, there is no need to separately provide a member for forming the coolant flow path 40, reducing the number of parts, reducing the manufacturing cost, and reducing the thickness of the separator. I can plan.

  Furthermore, in the present embodiment, a plurality of components are arranged side by side on the partition plate 100 and the receiving plate 101 so that a plurality of fuel cells can be arranged side by side. Therefore, the following effects can be obtained.

  1) By arranging a plurality of fuel cells in parallel, the stack height (thickness) necessary for obtaining the same power can be reduced. Therefore, it can be mounted even in places where the space in the height direction is small, such as under the vehicle body floor, and the degree of freedom of the mounting position is increased.

  2) When the same electric power is obtained, the size of each part of the partition plate 100 and the receiving plate 101 (the power generation / current collection unit 2, the storage unit 19, etc.) can be reduced as compared with a single fuel cell. Therefore, each part of the mold can be reduced, and the mold manufacturing cost can be suppressed.

  3) By reducing the stack height of the fuel cell, the cooling water flow path in each fuel cell is shortened, and the cooling water discharge performance is improved.

  4) By arranging a plurality of fuel cells in parallel, even when a certain fuel cell becomes unusable, power supply can be secured by the remaining fuel cells.

  5) Since cooling water can be convected between adjacent fuel cells, the cooling efficiency of heat generated during power generation is high.

  6) Since the fuel flow path extends in the horizontal direction (lateral direction) and the fuel flows through each fuel flow path from the upper stage to the lower stage, the discharge performance of the reaction water generated on the air electrode side is good. That is, when the fuel flow path extends in the vertical direction, there is a fuel flow path in which water has to move from the lower side to the upper side against gravity, so that the discharge performance is deteriorated. The same problem occurs when fuel is allowed to flow from the lower stage to the upper stage. Considering this, it is preferable to design at least air (or oxygen) to flow from the upper stage to the lower stage in the fuel flow path.

  By the way, in the fuel cell 36 of this embodiment, when the unit cell 37 and the separator 29 'for forming the coolant flow path are stacked, it is necessary to join the receiving plates 101 that are in contact with each other. The reason for this is to ensure energization between the receiving plates 101 and to stop the coolant channel 40 formed between the receiving plates 101.

  As means for joining the receiving plates 101 together, joining by an adhesive or joining by welding can be considered. However, joining with an adhesive requires a special adhesive having electrical conductivity, which increases the cost, and it is difficult to uniformly apply the adhesive, resulting in poor productivity. In addition, in the case of welding joining, it is difficult to maintain the joining quality constant, and welding distortion may occur in the receiving plate 101, which may adversely affect performance.

  Therefore, the present applicant has invented a fuel cell as shown in FIGS. 14 to 16 in order to solve these problems.

  As can be seen from FIG. 14, the fuel cell includes the edges of the receiving plates 101 that are in contact with each other and the holes for supplying or discharging the fuel (first and second communication holes 22 a and 22 b, first and second isolations). The edges of the holes 23a, 23b) are caulked and joined. Specifically, as shown in FIG. 15, the edge of the receiving plate 101 (the end of the flange portion 21) located on the upper side in the drawing is bent so as to stand up at a predetermined angle θ with respect to the surface of the receiving plate 101. The rising portion 50 is formed, and the edge portion (the end portion of the flange portion 21) of the receiving plate 101 located on the lower side in the drawing is bent so as to wrap the rising portion 50 to form the caulking joint portion 51. .

  Further, as shown in FIG. 16, the edge (the overhanging portion 25 or the separating portion 26) of the holes 22 a, 22 b, 23 a, 23 b for supplying or discharging the fuel in the upper receiving plate 101 is formed on the surface of the receiving plate 101. On the other hand, the upright portion 52 is formed by bending so as to stand up at a predetermined angle (approximately 90 ° in the figure), and a hole for supplying or discharging fuel in the lower receiving plate 101 so as to wrap up the upright portion 52 The edge portions (the overhang portions 25 or the isolation portions 26) of 22a, 22b, 23a, and 23b are bent to form the caulking joint portion 53.

  That is, the upper receiving plate 101 is folded and crimped so as to be wrapped by the lower receiving plate 101, and such caulking can be achieved by press molding or roll molding.

  In this way, the edges of the receiving plates 101 and the edges of the fuel supply or discharge holes 22a, 22b, 23a, 23b are caulked and joined to each other on the outside of the coolant channel 40. Therefore, it is possible to ensure two functions required for the joint portion of the receiving plate 101, “ensure the conductivity” and “stop water of the coolant flow path 40”. In addition, the caulking bonding can be performed at a lower cost than the bonding by an adhesive, and the productivity is excellent. Further, compared with welding joining, it is easier to manage (homogenize) the joining quality and there is no possibility of adversely affecting the performance of the backing plate 101.

  As can be seen from FIG. 14, the fuel cell of the present embodiment includes the holes 39 a formed in the holding plate 39 and the first to fourth fuel supply / discharges formed in the partition plates 100 of the separators 29 and 29 ′. The holes 13 a, 13 b, 15 a, 15 b and the hole 35 formed in the MEA 33 are enlarged as compared with the embodiment shown in FIG. 13 because the holes 22 a and 22 b for supplying or discharging the fuel of the receiving plate 101 are used. , 23a, 23b for securing a jig insertion space when caulking the edges.

  Now, as shown in FIG. 14, in the fuel cell of this embodiment, the height h (see FIG. 15) of the caulking joint 51 at the edge of the backing plate 101 is not the upper caulking joint 51 ′. The distance W between the receiving plate 101 of one separator 29 and the receiving plate 101 of the other separator 29 in each unit cell 37 is set to be the same as or slightly larger. Thus, by setting the height h of the caulking joint portion 51 to be equal to or greater than the interval W between the receiving plates 101 of each unit cell 37, the caulking joint portion 51 can have a function as a spacer. As a result, the spacer 41 shown in FIG. 13 can be omitted, and the weight and manufacturing cost can be reduced. Moreover, it is not necessary to extend the partition plate 100 and MEA 33 of each unit cell 37 to the outer edge of the receiving plate 101 by providing the caulking joint portion 51 with a spacer function. That is, as shown in FIG. 14, the contours of the partition plate 100 and the MEA 33 can be downsized to the position of the convex portion 20 of the receiving plate 101, so that the yield can be improved and the weight and manufacturing cost can be reduced.

  As shown in FIGS. 14 and 15, in the fuel cell of the present embodiment, the rising angle θ of the caulking joints 51 and 51 ′ at the edge of the receiving plate 101 is set to an acute angle side from 90 °. In this way, when the unit cells 37 are tightened with bolts by tilting the rising angle θ of the caulking joints 51 and 51 ′ with respect to the line perpendicular to the surface of the plate 101, the caulking joint 51 Since the unit cells 37 are slightly elastically deformed and pressed against each other by the elastic force (spring effect), the adhesion between the unit cells 37 can be enhanced.

  By the way, in the form shown in FIG. 14, the interval W between the receiving plates 101 of each unit cell 37 and the interval between the receiving plate 101 and the pressing plate 39 of the separator 29 ′ for forming the coolant channel located at the uppermost part. Since W ′ is different, it is necessary to make the height different between the uppermost caulking joint 51 ′ and the other caulking joint 51. For this reason, two types of caulking jigs are required, leading to an increase in capital investment costs.

  The form which solved this problem is shown in FIG. In this embodiment, the height h of all the caulking joints 51 is unified according to the interval W ″ between the receiving plate 101 and the partition plate 100 of the separator 29 ′ for forming the coolant flow path. According to this configuration, it is only necessary to prepare one type of caulking jig, so that the capital investment cost can be suppressed. However, in this embodiment, the MEA 33 and the partition plate 100 of each unit cell 37 are enlarged in accordance with the outer edge of the receiving plate 101 and the upper side of each unit cell 37 is filled in order to fill a gap generated as a result of lowering the caulking joint portion 51. It is necessary to arrange the spacer 41 between the receiving plate 101 of the separator 29 and the partition plate 100. Even in this embodiment, the number of spacers 41 can be halved as compared with the embodiment shown in FIG.

  Next, with reference to FIG. 18, a mode in which the unification of the caulking joint portion and the complete deletion of the spacer are achieved will be described.

  In this embodiment, the height h of all the caulking joint portions 51 is unified according to the interval W between the receiving plates 101 of each unit cell 37. Then, by forming a raised portion 52 that protrudes upward at the edge of the upper pressing plate 39, the upward protrusion of the uppermost caulking joint portion 51 is absorbed. Further, by forming the raised portion 53 at the edge of the lower pressing plate 39, the gap between the lower caulking joint portion 51 and the pressing plate 39 is absorbed. According to this structure, only one type of caulking jig is required, the spacer can be completely removed, and the MEA 33 and the partition plate 100 can be miniaturized, so that the effect of reducing the weight and manufacturing cost can be maximized. .

  The present invention is not limited to the embodiment described above.

  For example, the shape of the caulking joint portions 51 and 53 is shown as an example, and other shapes may be used. As an example, in the above embodiment, the rising angle θ of the caulking joint 51 is set to an acute angle side from 90 °. However, the present invention is not limited in this respect, and is set to an obtuse angle side from 90 °. Or 90 °.

  Another modification of the caulking joint is shown in FIG. The caulking joint portion 55 is formed by further bending the entire caulking joint portions 51 and 53 shown in FIGS. 15 and 16 so as to be positioned substantially parallel to the surface of the receiving plate 101. According to this embodiment, it is possible to further improve the adhesion (conductivity) between the receiving plates 101 and the water stoppage. Also in the caulking joint 55, if the height h is set to be equal to or greater than the interval W between the receiving plates 101 of the unit cell 37, it can have a function as a spacer.

  Furthermore, although the example which crimps and joins only the receiving plates 101 was shown in the said embodiment, this invention is not limited in this point, Combined with the adjacent two receiving plates 101, either one or both receiving plates The partition plate 100 superimposed on 101 may be integrally caulked and joined. For example, as shown in FIGS. 20 and 21, a fuel supply or discharge hole (first to fourth fuel supply / discharge holes 13a, 13a, 13 b, 15 a, 15 b) are bent to form the standing portion 56, and the lower receiving plate 101 is wrapped so as to wrap both the standing portion 56 and the rising portion 52 of the upper receiving plate 101. The crimp joint part 57 may be formed by bending. According to this structure, the water stoppage between the partition plate 100 and the receiving plate 101 can be stopped, so that the water stoppage of the fuel flow path 30 can be secured.

  Further, in order to further improve the water tightness of the caulking joints, a water stop agent (sealer) is provided between the receiving plates 101 or between the receiving plate 101 and the partition plate 100 in each of the caulking bonding portions 51, 53, 55, and 57. It may be interposed.

  Further, when the edges of the receiving plate 101 having a rectangular outline are caulked and joined as in the present embodiment, wrinkles may occur at the corners (corners) and the water stoppage may be lowered. The caulking joint may be welded to increase the water stoppage. This is because it is considered that there is little adverse effect due to welding distortion if only corners are welded.

  Further, in the above-described embodiment, three parallel type fuel cells have been described as an example. However, the present invention is not limited in this respect, and may be applied to a single fuel cell or two or more fuel cells arranged in parallel. Of course, it is applicable.

  In each unit cell and fuel cell, the number and length of the fuel flow paths 30 are not limited to those shown in the figure.

  Furthermore, in the above-described embodiment, the end positions k1 and k2 of the vertical wall 7 forming the fuel flow path 30 are alternately different, and the fuel is described as alternately turning back the fuel flow paths 30. However, the position of the end portion of the vertical wall 7 may be varied every plurality. For example, the fuel may flow in a plurality of adjacent fuel flow paths in the same direction, and then turn back at the end portion to flow into one or a plurality of fuel flow paths.

  In the above-described embodiment, the flow path cross-sectional area of the fuel flow path 30 is the same at all positions, but the present invention is not limited in this respect. For example, the cross-sectional area of each fuel flow path 30 may be different in the longitudinal direction, or the cross-sectional area of the fuel flow path 30a formed by the groove 9 and the fuel flow path 30b formed by the crosspiece 11 The cross-sectional area may be different.

It is a front view of the partition plate which is one of the structural members of a separator. It is a front view of the receiving plate which is one of the structural members of a separator. It is an enlarged front view of the 1st component of the partition plate of FIG. It is the A section enlarged view of FIG. It is the VV sectional view taken on the line of FIG. It is an enlarged front view of the 1st component of the receiving plate of FIG. (A) is the VIIa-VIIa sectional view taken on the line of FIG. 6, (b) is the VIIb-VIIb sectional view of FIG. 6, (c) is the VIIc-VIIc sectional view of FIG. It is a front perspective view which shows the state which accumulated the 1st component of the partition plate and the 1st component of the receiving plate. It is the IX-IX sectional view taken on the line of FIG. It is an expanded view which shows one unit cell among parallel type | mold unit cells. It is sectional drawing along the XI-XI line of FIG. 10, and has shown the state which joined the separator and MEA. It is a partial side sectional view of a parallel type fuel cell configured by stacking parallel type unit cells. It is the B section enlarged view of FIG. It is a partial side sectional view of the fuel cell of the present invention. It is the C section enlarged view of FIG. It is the D section enlarged view of FIG. It is a partial side sectional view of the fuel cell of other embodiments of the present invention. It is a partial side sectional view of the fuel cell of other embodiments of the present invention. It is sectional drawing which shows the modification of a crimping junction part. It is a partial side sectional view of the fuel cell of other embodiments of the present invention. It is the E section enlarged view of FIG.

Explanation of symbols

2 Power generation / collection part 3 Slot (hole)
7 Vertical wall 10 Bottom wall 13a First fuel supply / discharge hole (fuel supply / discharge hole)
13b Second fuel supply / discharge hole (fuel supply / discharge hole)
15a Third fuel supply / discharge hole (fuel supply / discharge hole)
15b Fourth fuel supply / discharge hole (fuel supply / discharge hole)
19 accommodating part 20 convex part 22a 1st through hole (hole for fuel supply or discharge)
22b Second communication hole (fuel supply or discharge hole)
23a First isolation hole (fuel supply or discharge hole)
23b Second isolation hole (hole for fuel supply or discharge)
29 Separator 33 MEA
36 Fuel cell 37 Unit cell 40 Coolant flow path 51 Caulking joint part 53 Caulking joint part 57 Caulking joint part 100 Partition plate 101 Base plate

Claims (6)

  A partition plate made of a conductive metal plate having a power generation / current collection unit having a plurality of holes and vertical walls and bottom walls formed between the holes, and the power generation / current collection unit of the partition plate A separator is formed by superimposing a receiving plate made of a conductive metal plate having an accommodating portion for accommodating the separator, and the separator is disposed on each side of the MEA so that the partition plate is in contact with the MEA. A plurality of unit cells are formed such that the separator receiving plates are in contact with each other, and the edges of the receiving plates that are in contact with each other are caulked and joined to form a unit cell. A fuel cell characterized in that it is fixedly configured.   The backing plate has a convex portion that partially protrudes toward the partition plate, and when a plurality of the unit cells are stacked, a coolant flow path is formed between the convex portions of the backing plate that are in contact with each other. The fuel cell according to claim 1, wherein the coolant passage is stopped by caulking and joining the edges of the backing plate.   The fuel cell according to claim 1 or 2, wherein the height of the caulking joint at the edge of the backing plate is set to be equal to or greater than the distance between the backing plate of one separator and the backing plate of the other separator in each unit cell. The standing angle of the edge of the backing plate with respect to the surface of the backing plate of the caulking joint is set to an acute angle side or an obtuse angle side from 90 °,
4. The fuel cell according to claim 3, wherein when the unit cells are integrally fixed, the caulking joint is elastically deformed and the unit cells are brought into close contact with each other by the elastic force.   The fuel cell according to any one of claims 1 to 4, wherein a hole for supplying or discharging fuel is formed in the receiving plate, and edges of the holes of the receiving plates that are in contact with each other are caulked and joined. A hole for supplying or discharging the fuel is formed in the partition plate, and is overlapped with one or both of the receiving plates together with the edge of the hole for supplying or discharging the fuel of the receiving plate in contact with each other. 6. The fuel cell according to claim 5, wherein an edge of a hole for supplying or discharging fuel in the partition plate is caulked and joined.

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