JP4358083B2 - Fuel cell - Google Patents

Description

  The present invention provides an internal manifold type in which an electrolyte / electrode structure in which an electrolyte is disposed between a pair of electrodes and a separator are laminated, and at least the separator is formed with a reaction gas communication hole and a cooling medium communication hole. The present invention relates to a fuel cell.

  For example, in a polymer electrolyte fuel cell, an electrolyte membrane / electrode structure (MEA) in which an anode side electrode and a cathode side electrode are provided on both sides of an electrolyte membrane made of a polymer ion exchange membrane is sandwiched between separators. It has a power generation cell. This type of fuel cell is normally used as a fuel cell stack by stacking a predetermined number of power generation cells.

  In this fuel cell, a fuel gas, for example, a gas mainly containing hydrogen (hereinafter also referred to as hydrogen-containing gas) is supplied to the anode side electrode, while an oxidant gas, for example, A gas or air mainly containing oxygen (hereinafter also referred to as oxygen-containing gas) is supplied. In the fuel gas supplied to the anode side electrode, hydrogen is ionized on the electrode catalyst and moves to the cathode side electrode side through the electrolyte membrane. Electrons generated during that time are taken out to an external circuit and used as direct current electric energy.

  In the power generation cell described above, various seal structures are employed in order to keep the fuel gas and the oxidant gas airtight. For example, Patent Document 1 discloses a seal structure capable of improving the sealing performance by preventing deformation of a plate incorporated in a fuel cell stack.

  As shown in FIG. 10, the fuel cell stack incorporating this seal structure includes a unit cell 1, and the unit cell 1 includes first and second battery plates 3 and 4 that sandwich a membrane electrode assembly 2. Yes. An anode electrode 2 a and a cathode electrode 2 b are provided on both surfaces of the membrane electrode assembly 2.

  At the four corners of the first and second battery plates 3 and 4, cooling water supply ports W1 and discharge ports W2, and fuel gas supply ports G1 and discharge ports G2 are formed penetrating in the stacking direction. A fuel gas flow path (not shown) is formed on the surface 3a of the first battery plate 3 facing the anode electrode 2a, while the water flow path 5 extends along the vertical direction on the surface 3b opposite to the surface 3a. Is formed.

  A convex seal portion 6 is provided on the surface 3b so as to surround the cooling water supply port W1, the water flow path 5, and the cooling water discharge port W2. The fuel gas supply port G <b> 1 and the discharge port G <b> 2 are closed from the water flow path 5 by the convex seal portion 6.

  An oxidant gas flow path 7 is formed in the vertical direction on the surface 4a of the second battery plate 4 facing the cathode electrode 2b. The surface 4a is provided with a convex seal portion 6b surrounding the oxidant gas supply manifold 8a, the oxidant gas flow path 7, and the oxidant gas discharge flow path 8b.

  When the first battery plate 3 and the second battery plate 4 are joined with the membrane electrode assembly 2 sandwiched therebetween, the respective convex seal portions 6a and 6b are located on substantially the same line along the stacking direction. Yes. The first battery plate 3 is provided with rib portions 9a and 9b and small protrusions 9c corresponding to locations where the shape patterns of the convex seal portions 6a and 6b are different.

JP 2004-207042 A (FIGS. 1 to 3)

  By the way, in the above-mentioned Patent Document 1, overloading is applied to the first battery plate 3 and the second battery plate 4 at the portion where the convex seal portions 6a and 6b are located on the same line in the stacking direction. However, it is possible to prevent the deformation of these.

  However, only the rib portions 9a and 9b and the small protrusions 9c are disposed on the convex seal portion 6b at the portions having different shape patterns. Therefore, the load balance in the plane of the single cell 1 and the load balance for each single cell 1 are not made uniform, and in particular, it becomes difficult to maintain the power generation plane at a required surface pressure. As a result, there is a problem in that the sealing performance is deteriorated, the supply of the reaction gas is poor due to the blockage of the gas flow path, and the like.

  The present invention solves this type of problem, and provides a fuel cell capable of preventing a variation in local surface pressure with respect to a load in the stacking direction and ensuring a desired sealing function and power generation performance. The purpose is to provide.

  The present invention provides an internal manifold type in which an electrolyte / electrode structure in which an electrolyte is disposed between a pair of electrodes and a separator are laminated, and at least the separator is formed with a reaction gas communication hole and a cooling medium communication hole. It is a fuel cell.

  A seal member is provided on one surface of the separator to surround the outer periphery of the electrode. On the other surface of the separator, a cooling medium flow path for supplying the cooling medium along the surface direction, guiding the cooling medium between the cooling medium communication hole and the cooling medium flow path, and a seal member A guide portion extending in the intersecting direction and a receiving portion overlapping with the seal member in the stacking direction are provided.

  The receiving portion has a curved portion integrated at an acute angle on the way of the guide portion. Here, “intersecting at an acute angle” means that the intersection of the receiving portion and the guide portion is not a right angle.

  Moreover, it is preferable that the rib part which overlaps a part of guide part in the lamination direction is integrally formed with the sealing member on one surface of the separator. It is because a guide part and a rib part overlap and it can prevent a surface pressure loss reliably.

  Further, according to the present invention, an electrolyte membrane / electrode structure in which a first electrode and a second electrode having a larger surface area than the first electrode are disposed on both sides of the electrolyte membrane is disposed between the first and second separators. In addition, at least the first and second separators are internal manifold fuel cells in which a reaction gas communication hole and a cooling medium communication hole are formed.

  A first seal member that surrounds the outer periphery of the first electrode is provided on one surface of the first separator. A second seal member is provided on one surface of the second separator so as to surround the outer periphery of the second electrode and be displaced from the position of the first seal member. The other surface of the first separator or the second separator guides the cooling medium between the cooling medium flow path for supplying the cooling medium along the surface direction, the cooling medium communication hole, and the cooling medium flow path. And a guide portion extending in a direction intersecting with the first seal member, a first receiving portion overlapping with the first seal member in the stacking direction, and overlapping with the second seal member in the stacking direction and between the guide portions. The 2nd receiving part arrange | positioned at is provided. And the 1st receiving part has a curved part integrated at an acute angle in the middle of a guide part.

  Furthermore, it is preferable that the first seal member is integrally formed with a rib portion that overlaps a part of the guide portion in the stacking direction. It is because a guide part and a rib part overlap and it can prevent a surface pressure loss reliably.

  According to the present invention, when the fuel cell is tightened, an excessive deformation of the receiving portion due to the seal pressure can be prevented, and a local decrease in surface pressure (surface pressure loss) can be suppressed.

  Moreover, since the receiving portion that overlaps with the seal member in the stacking direction is integrated at an acute angle in the middle of the guide portion that extends in the direction intersecting with the seal member, for example, the receiving portion and the guide portion Compared with the case where the crossing at right angles, the increase in the surface pressure at the intersection is reduced at once. For this reason, it is possible to prevent the receiving portion and the guide portion from sagging and to ensure a desired sealing function and power generation performance.

  In the present invention, since the second receiving portion is provided between the guide portions, the cooling medium can smoothly flow between the cooling medium communication hole and the cooling medium flow path, and the stagnation and disturbance of the cooling medium can be achieved. It becomes possible to stop the flow. Thereby, cooling efficiency can be improved favorably.

  FIG. 1 is an exploded perspective view of a main part of a power generation cell 10 constituting a fuel cell according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view of the power generation cell 10 taken along line II-II in FIG. It is.

  As shown in FIG. 1, the power generation cell 10 is configured by sandwiching an electrolyte membrane / electrode structure 12 between an anode-side metal separator (first separator) 14 and a cathode-side metal separator (second separator) 16. The anode-side metal separator 14 and the cathode-side metal separator 16 are made of, for example, a steel plate, a stainless steel plate, an aluminum plate, a plated steel plate, or a metal plate whose surface is subjected to anticorrosion treatment.

  An oxidant gas inlet for supplying an oxidant gas, for example, an oxygen-containing gas, to one end edge of the power generation cell 10 in the long side direction (the arrow B direction in FIG. 1) communicates with each other in the arrow A direction. A communication hole 18a and a fuel gas outlet communication hole 20b for discharging a fuel gas, for example, a hydrogen-containing gas, are provided.

  The other end edge in the long side direction of the power generation cell 10 communicates with each other in the direction of arrow A, and a fuel gas inlet communication hole 20a for supplying fuel gas, and an oxidant gas for discharging oxidant gas An outlet communication hole 18b is provided.

  Cooling medium inlet communication holes 22a and 22a for supplying a cooling medium are provided at the upper edge of the power generation cell 10, and a cooling medium for discharging the cooling medium at the lower edge of the power generation cell 10. Outlet communication holes 22b and 22b are provided.

  The electrolyte membrane / electrode structure 12 includes, for example, a solid polymer electrolyte membrane 24 in which a perfluorosulfonic acid thin film is impregnated with water, and an anode side electrode (first electrode) 26 sandwiching the solid polymer electrolyte membrane 24. And a cathode side electrode (second electrode) 28. The anode side electrode 26 has a smaller surface area than the cathode side electrode 28 (see FIGS. 1 and 2).

  The anode-side electrode 26 and the cathode-side electrode 28 are uniformly coated with a gas diffusion layer (not shown) made of carbon paper or the like and porous carbon particles carrying a platinum alloy on the surface thereof. And an electrode catalyst layer (not shown) formed. The electrode catalyst layers are formed on both surfaces of the solid polymer electrolyte membrane 24.

  As shown in FIG. 3, a fuel gas flow path 30 communicating with the fuel gas inlet communication hole 20a and the fuel gas outlet communication hole 20b is formed on the surface 14a of the anode side metal separator 14 facing the electrolyte membrane / electrode structure 12. It is formed. The fuel gas channel 30 is constituted by a plurality of grooves extending in the direction of arrow B, for example.

  As shown in FIG. 4, a cooling medium flow path 32 communicating with the cooling medium inlet communication hole 22 a and the cooling medium outlet communication hole 22 b is formed on the surface 14 b of the anode side metal separator 14. The cooling medium flow path 32 includes a plurality of grooves extending in the arrow C direction.

  As shown in FIG. 1, the surface 16a of the cathode-side metal separator 16 facing the electrolyte membrane / electrode structure 12 is provided with an oxidant gas flow path 34 composed of a plurality of grooves extending in the arrow B direction, The oxidant gas flow path 34 communicates with the oxidant gas inlet communication hole 18a and the oxidant gas outlet communication hole 18b.

  As shown in FIGS. 1, 3, and 4, the first elastic seal 40 is integrated with the surfaces 14 a and 14 b of the anode side metal separator 14 around the outer peripheral edge of the anode side metal separator 14. Is done. For the first elastic seal 40, for example, EPDM, NBR, fluorine rubber, silicone rubber, fluorosilicone rubber, butyl rubber, natural rubber, styrene rubber, chloroprene or acrylic rubber or the like, cushioning material, or packing material is used. It is done.

  The first elastic seal 40 includes an anode side seal member (first seal member) 42 integrated with the surface 14a of the anode side metal separator 14, and a cooling medium side seal member 44 integrated with the surface 14b. The anode-side seal member 42 and the cooling medium-side seal member 44 can be selected from various cross-sectional shapes such as a tapered tip shape, a trapezoidal shape, or a bowl shape. A plurality of supply hole portions 45a and discharge hole portions 45b are formed in the anode side metal separator 14 so as to be close to the fuel gas inlet communication hole 20a and the fuel gas outlet communication hole 20b.

  As shown in FIG. 2, the anode side sealing member 42 is positioned outside the anode side electrode 26 constituting the electrolyte membrane / electrode structure 12 and directly contacts the solid polymer electrolyte membrane 24. As shown in FIG. 4, the cooling medium side sealing member 44 communicates the cooling medium inlet communication hole 22 a and the cooling medium outlet communication hole 22 b to the cooling medium flow path 32, and oxidant gas from the cooling medium flow path 32. The inlet communication hole 18a, the fuel gas outlet communication hole 20b, the fuel gas inlet communication hole 20a, and the oxidant gas outlet communication hole 18b are shielded.

  As shown in FIG. 1, the second elastic seal 46 is integrated with the surfaces 16 a and 16 b of the cathode side metal separator 16 around the outer peripheral edge of the cathode side metal separator 16. The second elastic seal 46 includes a cathode side seal member (second seal member) 48 integrated with the surface 16 a of the cathode side metal separator 16. The cathode-side seal member 48 is configured in the same manner as the anode-side seal member 42 and is displaced outward from the anode-side seal member 42 with respect to the stacking direction.

  As shown in FIGS. 1 and 2, the cathode side seal member 48 is located outside the electrolyte membrane / electrode structure 12 and directly contacts the surface 14 a of the anode side metal separator 14, and also has an oxidant gas inlet communication hole. 18 a and the oxidant gas outlet communication hole 18 b communicate with the oxidant gas flow path 34.

  The anode-side seal member 42 is integrally formed with a plurality of first rib portions 52 that protrude toward the cathode-side seal member 48 to a position where the anode-side seal member 48 does not interfere with the cathode-side seal member 48 (see FIG. 3). The cathode-side seal member 48 is integrally formed with a plurality of second rib portions 54 that extend to a position that faces the anode-side seal member 42 and does not interfere with the outer peripheral portion of the electrolyte membrane / electrode structure 12 (see FIG. 2). ).

  The 1st rib part 52 and the 2nd rib part 54 are mutually arrange | positioned in zigzag form. A plurality of third rib portions 56 that face the second rib portion 54 and protrude toward the second rib portion 54 are integrally formed on the anode side sealing member 42 (see FIG. 2).

  As shown in FIG. 4, a plurality of guide portions 58 a and 58 b, a first receiving portion 60, and a second receiving portion 62 are provided on the surface 14 b of the anode side metal separator 14 integrally with the cooling medium side sealing member 44. The guide portions 58a and 58b are provided between the cooling medium inlet communication hole 22a and the cooling medium outlet communication hole 22b and the cooling medium flow path 32, and extend in a direction (arrow C direction) intersecting the anode-side seal member 42. And provided at a position overlapping the first and third rib portions 52 and 56 in the stacking direction. The first and third rib portions 52 and 56 function to prevent the anode side metal separator 14 from being deformed by the sealing pressure when a tightening load is applied to the power generation cell 10 in the stacking direction, that is, the guide portions 58a and 58b. Has a function as a backing.

  The first receiving portion 60 is provided at a position overlapping with the anode-side seal member 42 in the stacking direction, and is curved and integrated with the guide portions 58a and 58b at an acute angle (that is, without intersecting at a right angle). , 60b. The guide portions 58a and 58b are spaced apart from each other by a predetermined distance to form a cooling medium passage 64, and the second receiving portion 62 is provided between the passages 64 so as to extend in the direction of arrow B. This 2nd receiving part 62 is provided in the position which overlaps with the cathode side sealing member 48 of the cathode side metal separator 16 with respect to the lamination direction (refer FIG.2 and FIG.5).

  The operation of the power generation cell 10 configured as described above will be described below.

  First, as shown in FIG. 1, an oxidant gas such as an oxygen-containing gas is supplied to the oxidant gas inlet communication hole 18a, and a fuel gas such as a hydrogen-containing gas is supplied to the fuel gas inlet communication hole 20a. Further, a cooling medium such as pure water, ethylene glycol, or oil is supplied to the cooling medium inlet communication hole 22a.

  Therefore, the oxidant gas is introduced into the oxidant gas flow path 34 of the cathode side metal separator 16 from the oxidant gas inlet communication hole 18a, moves in the direction of arrow B, and the cathode side electrode of the electrolyte membrane / electrode structure 12 28. On the other hand, the fuel gas is introduced into the fuel gas flow path 30 of the anode side metal separator 14 from the fuel gas inlet communication hole 20a through the supply hole 45a. The fuel gas moves in the direction of arrow B along the fuel gas flow path 30 and is supplied to the anode electrode 26 of the electrolyte membrane / electrode structure 12.

  Therefore, in each electrolyte membrane / electrode structure 12, the oxidant gas supplied to the cathode side electrode 28 and the fuel gas supplied to the anode side electrode 26 are consumed by an electrochemical reaction in the electrode catalyst layer. Power generation is performed.

  Next, the oxidant gas consumed by being supplied to the cathode side electrode 28 is discharged in the direction of arrow A along the oxidant gas outlet communication hole 18b. Similarly, the fuel gas consumed by being supplied to the anode side electrode 26 passes through the discharge hole 45b and is discharged in the direction of arrow A along the fuel gas outlet communication hole 20b.

  Further, the cooling medium supplied to the cooling medium inlet communication hole 22a is introduced into the cooling medium flow path 32 of the anode side metal separator 14 and then flows in the direction of arrow C. This cooling medium is discharged from the cooling medium outlet communication hole 22b after the electrolyte membrane / electrode structure 12 is cooled.

  In this case, in this embodiment, as shown in FIGS. 4 and 5, the surface 14b of the anode-side metal separator 14 is provided with a first receiving portion 60 that overlaps the anode-side seal member 42 in the stacking direction. The first receiving portion 60 is integrated at an acute angle in the middle of the guide portions 58a and 58b extending in the direction of arrow C. Furthermore, the surface 14b is provided with a second receiving portion 62 that overlaps the cathode-side seal member 48 in the stacking direction. For this reason, when the power generation cell 10 is tightened in the stacking direction, deformation of the anode-side metal separator 14 can be effectively prevented.

  In addition, since the first receiving portion 60 is integrated in the middle of the guide portions 58a and 58b, excessive deformation of the first receiving portion 60 due to the sealing pressure can be prevented, and a local reduction in surface pressure ( It is possible to suppress (surface pressure loss).

  Further, the curved portions 60a and 60b provided at both ends of the receiving portion are integrated with the guide portions 58a and 58b at an acute angle. Accordingly, it is possible to prevent an excessive surface pressure from being generated in the first receiving part 60, and to prevent the first receiving part 60 from sagging and to ensure a desired sealing function and power generation performance. The effect that it becomes possible is acquired.

  Therefore, the embodiment shape pattern comprising the guide portions 58a, 58b, the first receiving portion 60 and the second receiving portion 62 of the present embodiment, and the first to fourth comparative shape patterns 70 to 76 shown in FIGS. Was used to compare the surface pressure loss and the intersection surface pressure.

  The first comparative shape pattern 70 shown in FIG. 6 has a plurality of first receiving portions 70a and second receiving portions 70b extending in the direction of arrow B, and there is no intersecting portion. For this reason, although the increase in the cross-section surface pressure is not caused, the end portions 70a1 and 70b1 of the first and second receiving portions 70a and 70b are easily deformed, and the surface pressure loss is generated remarkably.

  The second comparative shape pattern 72 shown in FIG. 7 has a plurality of first receiving portions 72a and second receiving portions 72b extending in the direction of arrow B, respectively, and the direction of arrow C from the middle of the first receiving portion 72a. The guide portions 72c and 72d are integrally molded. In the second comparative shape pattern 72, since the curved guide portions 72c and 72d are provided, the surface pressure at the intersecting portion is not increased, but the deformation is caused at the end portions 72a1 of the first receiving portions 72a that are close to each other. As a result, the surface pressure loss occurred at the end portion 72a1.

  The third comparative shape pattern 74 shown in FIG. 8 has a first receiving portion 74a and a second receiving portion 74b, and the first receiving portion 74a has guide portions 74c and 74d that are curved and are directed in the direction of arrow C. Provided integrally. In the third comparative shape pattern 74, a space portion 74e exists mainly corresponding to the outside of the curved portions of the guide portions 74c and 74d, and a more remarkable surface pressure loss occurs in the space portion 74e. It was.

  The fourth comparative shape pattern 76 shown in FIG. 9 has first and second receiving portions 76a and 76b, and guide portions 76c and 76d extending in the direction of arrow C are perpendicular to the first receiving portion 76a. Intermingled and integrated. Thereby, it is difficult to deform at the right corner portion 76e, and the surface pressure at the intersecting portion is considerably increased.

  By the way, in this embodiment, the 2nd receiving part 62 is provided between the channel | path 64 for cooling media formed of the guide parts 58a and 58b. Therefore, the cooling medium does not stay between the passages 64 and turbulent flow does not occur, and the cooling medium inlet communication hole 22a, the cooling medium outlet communication hole 22b, and the cooling medium flow path 32 are not cooled. Can flow smoothly. Thereby, the advantage that the cooling efficiency of the electrolyte membrane and electrode structure 12 improves favorably is obtained.

  In addition, first and third rib portions 52 and 56 that function as backings for the guide portions 58a and 58b are provided, and the first and third rib portions 52 and 56 are connected to the second rib portion 54 and a staggered pattern. It is arranged in a shape. Therefore, it is possible to effectively prevent the gas from being short-cut between the anode side seal member 42 and the cathode side seal member 48.

It is a principal part disassembled perspective explanatory view of the power generation cell which constitutes the fuel cell concerning the embodiment of the present invention. It is II-II sectional view explanatory drawing in FIG. 1 of the said electric power generation cell. It is explanatory drawing of one surface of the anode side metal separator which comprises the said electric power generation cell. It is explanatory drawing of the other surface of the said anode side metal separator. It is a partial cross-section exploded perspective view of the power generation cell. It is explanatory drawing of the 1st comparison shape pattern compared with the shape pattern of this invention. It is explanatory drawing of the 2nd comparison shape pattern compared with the shape pattern of this invention. It is explanatory drawing of the 3rd comparison shape pattern compared with the shape pattern of this invention. It is explanatory drawing of the 4th comparison shape pattern compared with the shape pattern of this invention. It is explanatory drawing of the seal structure disclosed by patent document 1. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Power generation cell 12 ... Electrolyte membrane electrode assembly 14 ... Anode side metal separator 16 ... Cathode side metal separator 18a ... Oxidant gas inlet communication hole 18b ... Oxidant gas outlet communication hole 20a ... Fuel gas inlet communication hole 20b ... Fuel Gas outlet communication hole 22a ... Cooling medium inlet communication hole 22b ... Cooling medium outlet communication hole 24 ... Solid polymer electrolyte membrane 26 ... Anode side electrode 28 ... Cathode side electrode 30 ... Fuel gas flow path 32 ... Cooling medium flow path 34 ... Oxidation Agent gas flow paths 40, 46 ... elastic seal 42 ... anode side seal member 44 ... cooling medium side seal member 48 ... cathode side seal members 52, 54, 56 ... rib portions 58a, 58b ... guide portions 60, 62 ... receiving portions 60a 60b ... curved portion 64 ... passage

Claims (4)

An internal manifold type fuel cell in which an electrolyte / electrode structure having an electrolyte disposed between a pair of electrodes and a separator are stacked, and at least the separator has a reaction gas communication hole and a cooling medium communication hole formed therethrough. And
On one surface of the separator, a seal member that surrounds the outer periphery of the electrode is provided,
On the other surface of the separator, a cooling medium flow path for supplying a cooling medium along the surface direction;
A guide portion that guides the cooling medium between the cooling medium communication hole and the cooling medium flow path and extends in a direction intersecting the seal member;
A receiving portion that overlaps the sealing member in the stacking direction;
The fuel cell is characterized in that the receiving portion has a curved portion integrated at an acute angle in the middle of the guide portion.   2. The fuel cell according to claim 1, wherein a rib portion that overlaps a part of the guide portion in the stacking direction is formed integrally with the seal member on one surface of the separator. An electrolyte membrane / electrode structure in which a first electrode and a second electrode having a larger surface area than the first electrode are disposed on both sides of the electrolyte membrane is disposed between the first and second separators, and at least The first and second separators are internal manifold fuel cells in which a reaction gas communication hole and a cooling medium communication hole are formed,
On one surface of the first separator, a first seal member that surrounds the outer periphery of the first electrode is provided,
On one surface of the second separator, a second seal member is provided that surrounds the outer periphery of the second electrode and is displaced from the position of the first seal member.
A cooling medium flow path for supplying a cooling medium along a surface direction to the other surface of the first separator or the second separator;
A guide portion that guides the cooling medium between the cooling medium communication hole and the cooling medium flow path and extends in a direction intersecting the first seal member;
A first receiving portion overlapping the first seal member in the stacking direction;
A second receiving portion that overlaps the second seal member in the stacking direction and is disposed between the guide portions;
The fuel cell is characterized in that the first receiving portion has a curved portion integrated at an acute angle in the middle of the guide portion.   4. The fuel cell according to claim 3, wherein the first seal member is integrally formed with a rib portion that overlaps a part of the guide portion in the stacking direction.

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