JP4708101B2 - Fuel cell voltage detection structure - Google Patents

Description

  The present invention relates to a fuel cell voltage detection structure for detecting the voltage of a fuel cell having a separator having a metal electrode reaction part and a resin outer peripheral part.

  For example, as a polymer electrolyte fuel cell, a membrane electrode structure in which an anode (hydrogen electrode) and a cathode (air electrode) are provided on both sides of an electrolyte membrane made of a polymer ion exchange membrane (cation exchange membrane), respectively. It is known that a body is formed, and further, a plurality of fuel cells each formed by sandwiching the membrane electrode structure with a pair of separators are formed.

As a separator for this type of fuel cell, in order to enhance corrosion resistance and insulation, a technique using a separator having a resin outer periphery around a metal center has been proposed (Patent Literature). 1, see Patent Document 2).
JP 2003-77499 A JP 2004-296138 A

  By the way, it is difficult to obtain sufficient power for driving an automobile with only one fuel cell. Therefore, a fuel cell having a stack structure in which a plurality of fuel cells each having a membrane electrode structure sandwiched between a pair of separators is stacked so as to supply sufficient electric power for the driving is formed, and the fuel cell is mounted on an automobile. Is being considered. In this case, it is very important to detect the voltage of each fuel cell in order to monitor whether each fuel cell constituting the fuel cell normally generates power.

However, in order to detect the voltage of each fuel cell, a terminal portion to be attached to the connector of the external voltage detector must be formed in each fuel cell. As a result, in the conventional techniques as described in Patent Documents 1 and 2 described above, when the terminal portion of each fuel cell is extended from the metal central portion and exposed from the resin outer peripheral portion, It becomes difficult to join the metal around the terminal portion and the outer peripheral portion. For this reason, there exists a problem that there exists a possibility that the sealing performance in the communicating hole of a reactive gas or a cooling medium cannot be ensured.
In the present invention, the metal at the periphery of the terminal portion and the outer periphery are well bonded, and the voltage of each fuel cell is detected while ensuring the sealing performance in the communication gas and cooling medium communication holes formed in the separator. An object of the present invention is to provide a fuel cell voltage detection structure that can be performed.

  The invention according to claim 1 is a fuel battery cell in which a membrane electrode structure (for example, the membrane electrode structure 7 in the embodiment) is sandwiched between a pair of separators (for example, the separators 9 and 10 in the embodiment). For example, the separator is applied to a fuel cell having the fuel cell 2) in the embodiment (for example, the fuel cell 1 in the embodiment), and each separator is made of a metal electrode reaction portion (for example, the electrode reaction surface in the embodiment). 11a, 12a) and a resin outer peripheral part (for example, outer peripheral parts 13 and 14 in the embodiment) provided on the outer periphery of the electrode reaction part, and a reaction gas or a cooling medium is communicated with the outer peripheral part. The communication holes (for example, the communication holes 21 to 26 in the embodiment) are formed, and a seal portion (for example, a resin member is melted by a laser around each communication hole). The sealing portions 21a to 26a) in the embodiment are respectively formed, and one of the pair of separators has a terminal portion protruding from the outer peripheral portion (for example, the terminal portion 17 in the embodiment). The terminal portion is formed by extending the electrode reaction portion, and is formed to be able to engage with a cell voltage detection connector (for example, the connector 41 in the embodiment) on a part of one surface thereof. A conductive portion (for example, the conductive portion 19 in the embodiment) and a resin portion (for example, the resin portion 20 in the embodiment) that covers the periphery of the conductive portion are provided.

  According to the present invention, the conductive portion that engages with the cell voltage detection connector is formed on a portion of one surface of the terminal portion, and the periphery thereof is covered with the resin portion. Also, it is possible to satisfactorily ensure the bonding between the metal and the resin that connect the conductive portion and the electrode reaction portion. And since the sealing part which melt | dissolved the resin member with the laser is each formed around each communicating hole, it becomes possible to ensure the sealing performance in each communicating hole.

The invention according to claim 2 is the invention according to claim 1, wherein the terminal portion is formed with a recess recessed with respect to the resin portion, and the conductive portion is exposed from the recess. And
According to this invention, since it engages with the detection connector via the recess, it is possible to prevent the engaged detection connector from coming off, and to improve the detection reliability of the cell voltage. Further, an increase in the thickness of the separator due to the formation of the conductive portion can be suppressed.

A third aspect of the present invention is the first aspect of the present invention, wherein the terminal portion is formed with a convex portion that protrudes with respect to the resin portion, and the conductive portion is exposed from the convex portion. It is characterized by that.
According to this invention, since it engages with the connector for detection via the convex portion, it is possible to engage with the connector for detection without contacting the resin portion, and durability of the terminal portion. Performance can be improved and the life can be extended.

The invention according to claim 4 is the invention according to any one of claims 1 to 3, wherein the other separator of the pair of separators has a dummy terminal portion at a position facing the terminal portion. (Dummy terminal portion 18 in the embodiment, for example) is formed, and the dummy terminal portion is formed in substantially the same shape as the terminal portion, and the outer surface is covered with resin.
According to this invention, since the shape of each separator can be made substantially the same, the manufacturing process of each separator can be made common, and in turn, the time required for manufacturing the fuel cell can be shortened.

The invention according to claim 5 is the invention according to claim 4, wherein among the fuel cells constituting the fuel cell, a terminal portion of one fuel cell and a stacking direction of the fuel cell The dummy terminal portion of the adjacent fuel cell is welded by a laser.
According to the present invention, since the rigidity of the terminal portion can be reinforced by the dummy terminal portion without increasing the thickness of each separator itself, the connection reliability with the connector can be improved.

According to the first aspect of the present invention, it is possible to detect the voltage of each fuel cell while ensuring the sealing performance in the communication gas and cooling medium communication holes formed in the separator.
According to the invention of claim 2, the detection reliability of the cell voltage can be improved. Further, an increase in the thickness of the separator due to the formation of the conductive portion can be suppressed.

According to the third aspect of the present invention, it is possible to engage with the detection connector without contacting the resin portion, to improve the durability of the terminal portion, and to extend the life. it can.
According to the invention which concerns on Claim 4, the manufacturing process of each separator can be made common, and it becomes possible to shorten the time which manufactures a fuel cell by extension.
According to the invention which concerns on Claim 5, connection reliability with the said connector can be improved.

Hereinafter, a fuel cell voltage detection structure according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a plan view showing a fuel cell according to an embodiment of the present invention. In the figure, the direction perpendicular to the paper surface is set as the stacking direction of the fuel cells 1.
As shown in the figure, separators 9 and 10 constituting the fuel cell 1 surround separator bodies 11 and 12 having electrode reaction surfaces 11a and 12a formed at the center thereof, and surround the outside of the electrode reaction surfaces 11a and 12a. The outer peripheral parts 13 and 14 are provided.

First, the separator bodies 11 and 12 will be described. FIG. 2 is a plan view showing the separator main body 11 constituting the separator 9. FIG. 3 is a plan view showing the separator main body 12 constituting the separator 10.
As shown in FIG. 2, the separator main body 11 is formed in a substantially rectangular shape, and includes a protruding metal portion 15 that protrudes outward from one side thereof. As shown in FIG. 3A, the separator body 12 is formed in the same shape as the separator body 11. In addition, as the separator main body 12, as shown in FIG.3 (b), you may use what does not form the protrusion metal part 15. FIG.

  Each of the separator bodies 11 and 12 is formed by pressing a metal plate material having a thickness of 0.1 to 0.5 mm to form a corrugated plate portion in which a large number of irregularities having a certain height are formed in a certain pattern. Has been. In the corrugated plate portion, the portions facing the anode 5 and the cathode 6 (see FIG. 7 for both) are electrode reaction surfaces 11a and 12a. On the other hand, the surface on the opposite side of the electrode reaction surfaces 11a and 12a among the corrugated plate portions becomes the coolant flow path surfaces 11b and 12b. In addition, as a metal which comprises the separator main bodies 11 and 12, it is preferable to use the thing made from stainless steel or titanium from points, such as rust prevention property.

Next, the separators 9 and 10 including the separator bodies 11 and 12 will be described. FIG. 4 is an overall plan view of the separator 9. FIG. 5 is an overall plan view of the separator 10.
As shown in these drawings, frame-shaped outer peripheral portions 13 and 14 are formed outside the separator main bodies 11 and 12. The outer peripheral portions 13 and 14 are configured by bonding a pair of resin films formed in a frame shape from above and below so as to sandwich the peripheral portions of the separator main bodies 11 and 12. Thus, the thickness precision of the outer peripheral parts 13 and 14 can be improved by comprising the outer peripheral parts 13 and 14 with a pair of resin film, respectively. As the resin, it is preferable to use a natural color thermoplastic resin such as PEEK (polyether ether ketone), PPS (polyphenylene sulfide), PPE (polyphenylene ether), PP (polypropylene).

  And a coupling agent is apply | coated between the separator main bodies 11 and 12 and a pair of resin sheet which comprises the outer peripheral parts 13 and 14, respectively. Thus, by applying a coupling agent, it becomes possible to adhere | attach the separator main bodies 11 and 12 and the outer peripheral parts 13 and 14 favorable. As the coupling agent, for example, a silane coupling material can be used.

In the outer peripheral portions 13 and 14, communication holes 21 to 24 for communicating the reaction gas (fuel gas, oxidant gas) of the fuel cell 1 and communication holes 25 and 26 for communicating a cooling medium are formed. Yes. In the present embodiment, the communication holes 21 and 22 are the fuel gas supply port and its discharge port, the communication holes 23 and 24 are the oxidant gas supply port and its discharge port, and the communication holes 25 and 26 are the cooling medium supply port and its discharge port. Each outlet is set.
The outer peripheral portion 13 is formed with a flow passage 31 through which fuel gas flows between the communication holes 21 and 22 and the electrode reaction surface 11a (see FIGS. 10 and 11). 10 and 11, the outer peripheral portion 14 is formed with a flow passage 32 through which an oxidant gas flows between the communication holes 23 and 24 and the electrode reaction surface 12a. . And in the said outer peripheral parts 13 and 14, the flow path 33 which distribute | circulates a cooling medium is formed between the communicating holes 25 and 26 and the cooling medium flow-path surfaces 11b and 12b. As shown in FIGS. 10 and 11, the flow passages 31 to 33 are formed radially from the communication holes 21 to 26 to the electrode reaction surfaces 11 a and 12 b or the cooling medium flow path surfaces 11 b and 12 b, thereby allowing reaction gas and cooling. The medium can be easily diffused and converged.

The separator 9 is formed with a terminal portion 17 protruding from the outer peripheral portion 13. The terminal portion 17 includes a conductive portion 19 formed by exposing the protruding metal portion 15 on one side (in this case, the same surface as the electrode reaction surface 11a) on the protruding end side, and a portion other than the conductive portion 19 in the protruding metal portion 15. The resin part 20 which covers is provided. In the present embodiment, as shown in FIG. 15A, the terminal portion 17 is formed with a recess recessed with respect to the resin portion 20, and the conductive portion 19 is exposed from the recess.
On the other hand, the separator 10 has a dummy terminal portion 18 formed at a position facing the terminal portion 17. The dummy terminal portion 18 is formed in substantially the same shape as the terminal portion 17, and the outer surface is covered with a resin. .

The fuel cell 2 is formed by sandwiching the membrane electrode structure (MEA) 7 between the separators 9 and 10, and the fuel cell 1 is configured by stacking the fuel cells 2.
As shown in FIG. 7, the membrane electrode structure 7 includes, for example, a solid polymer electrolyte membrane 4 made of a perfluorosulfonic acid polymer (hereinafter simply referred to as an electrolyte membrane), an anode 5 sandwiching both surfaces of the electrolyte membrane 4, and And a cathode 6.
The anode 5 and the cathode 6 are configured, for example, by laminating a catalyst layer made of an alloy mainly composed of Pt on one surface in contact with the electrolyte membrane 4 of a gas diffusion layer made of porous carbon cloth or porous carbon paper. ing.

  The electrolyte membrane 4 is formed in, for example, a substantially rectangular shape, and the outer dimensions thereof are the same as those of the separators 9 and 10. When the outer dimension of the electrolyte membrane 4 is used as a reference, the cathode 6 and the anode 5 have a stepped structure with a small size. The electrolyte membrane 4, the anode 5 and the cathode 6 are combined so that their centers of gravity coincide with each other, and the ratio of the dimensional difference at the periphery is set to be equal. In the electrolyte membrane 4, the communication holes 21 to 26 are formed at positions corresponding to the communication holes 21 to 26 formed in the separators 9 and 10.

  A corrugated plate portion formed on the electrode reaction surface 11 a of the separator body 11 defines a fuel gas flow path with the anode 5 constituting the membrane electrode structure 7. Similarly, a corrugated plate portion formed on the electrode reaction surface 12 a of the separator body 12 defines an oxidant gas flow path with the cathode 6. In addition, on the cooling medium flow surfaces 11b and 12b between the separator bodies 11 and 12 arranged to face each other, a flow path for flowing the cooling medium is defined by a corrugated plate portion formed on the back surface.

Then, a seal process is performed around the communication holes other than the reaction gas or the cooling medium that is allowed to flow through the flow path defined as described above, thereby prohibiting the flow through the flow path.
In the present embodiment, the seal portions 21a to 26a are formed by irradiating a laser to melt the resin around the communication holes 21 to 26. This will be described with reference to FIGS. As a laser to be irradiated, a semiconductor laser is preferably used because of its long life, high efficiency, and low cost.

  6 to 9, the separator 10 in FIG. 6 is positioned at the top, and the membrane electrode structure 7 in FIG. 7, the separator 9 in FIG. 8, and the separator 10 in FIG. At the bottom. In other words, with the separator 10 of FIG. 9 set, the separator 9 of FIG. 8, the membrane electrode structure 7 of FIG. 7, and the separator 10 of FIG. 6 are sequentially stacked. And whenever these are laminated | stacked, a seal part is formed with a laser.

Specifically, the separator 9 of FIG. 8 is set on the separator 10 shown in FIG. 9, and the peripheral portions of the communication holes 21 to 24 of the separator 9 are irradiated with laser. Thereby, the resin in the peripheral portions of the communication holes 21 to 24 in the separators 9 and 10 is melted by the irradiated laser and joined to each other, and seal portions 21 a to 24 a are formed around the communication holes 21 to 24. Therefore, only the cooling medium flows on the cooling medium flow surface 12b of the separator 10 through the communication holes 25 and 26, and the flow of the reaction gas flowing through the communication holes 21 to 24 is prohibited.
At this time, the terminal portion 17 formed on the separator 9 and the dummy terminal portion 18 formed on the separator 10 are welded by a laser.

  Next, the membrane electrode structure 7 of FIG. 7 is set on the separator 9 shown in FIG. 8, and the peripheral edge portions of the communication holes 23 to 26 of the membrane electrode structure 7 are irradiated with laser. Thereby, the resin of the peripheral part of the communication holes 23-26 in the membrane electrode structure 7 and the separator 9 is melted by the irradiated laser and joined to each other, and the seal parts 23a-26a are formed around the communication holes 23-26. It is formed. Therefore, only the fuel gas flows through the communication holes 21 and 22 on the electrode reaction surface 11a of the separator 9 (that is, the anode 5 of the membrane electrode structure 7), the oxidant gas flowing through the communication holes 23 to 26, and cooling. Distribution of media is prohibited.

  Then, the separator 10 of FIG. 6 is set on the membrane electrode structure 7 shown in FIG. 7, and laser is irradiated to the peripheral portions of the communication holes 21, 22, 25, 26 of the separator 10. Thereby, the resin at the peripheral portions of the communication holes 21, 22, 25, 26 in the membrane electrode structure 7 and the separator 10 is melted by the irradiated laser and joined to each other, and the communication holes 21, 22, 25, 26 are connected. Seal portions 21a, 22a, 25a, and 26a are formed around the periphery. Therefore, only the oxidant gas flows through the communication holes 23, 24 to the cathode 6 of the membrane electrode structure 7 (that is, the electrode reaction surface 12 a of the separator 10), and flows through the communication holes 21, 22, 25, 26. Distribution of fuel gas and cooling medium is prohibited.

Further, as described above, when the peripheral edge portions of the communication holes 21 to 26 are irradiated with laser, the outer peripheral edge portions of the membrane electrode structure 7 and the separators 9 and 10 are also irradiated with laser so that these portions are sealed. The parts 7a, 9a and 10a are formed.
These processes are sequentially repeated to form the fuel cell 2 and, in turn, the fuel cell 1.

In the fuel cell 1 configured as described above, as shown in FIG. 13, the fuel gas is supplied from the fuel gas supply port 21 through the flow passage 31 and flows through the electrode reaction surface 11 a. The gas is discharged from the fuel gas discharge port 22.
Further, the oxidant gas is supplied from the oxidant gas supply port 23 via the flow passage 32, flows through the electrode reaction surface 12 a, and is discharged from the oxidant gas discharge port 24.
The cooling medium is supplied from the cooling medium supply port 25, flows through the cooling medium flow surfaces 11 b and 12 b through the flow path 33, and is discharged from the cooling medium discharge port 26.

  In the fuel cell 1, hydrogen ions generated by the catalytic reaction at the anode 5 permeate the electrolyte membrane 4 and move to the cathode 6, causing an electrochemical reaction with oxygen at the cathode 6 to generate power. Although heat is generated with this power generation, the heat is cooled by the cooling medium flowing through the cooling medium flow path 29. Thereby, it is possible to generate power while maintaining the fuel cell 1 at an appropriate temperature.

  Here, the flow passages 31 and 32 for allowing the reaction gas to flow between the communication holes 21 to 24 and the electrode reaction surfaces 11a and 12a are provided in the resin outer peripheral portions 13 and 14 having resistance to pressure and heat. Since it is formed, the shape of the flow passages 31 and 32 can be kept substantially constant even when the outer peripheral portions 13 and 14 are pressurized or heated, and the flow rate of the reaction gas can be kept substantially constant. Can be secured. Thereby, the reliability of the fuel cell 1 can be improved.

  At this time, the electrodes facing each other in the fuel cells 2 and 2 adjacent in the stacking direction have the same potential. Therefore, if the terminal portion 17 is formed only on one separator (in this case, the separator 9) as in the present embodiment, the potential is applied from the terminal portions 17 and 17 of the fuel cells 2 and 2 adjacent to each other. By detecting, the voltage of each fuel cell 2 can be measured.

  FIG. 12 is a cross-sectional view of the main part showing a state where the connector 41 of the voltage measuring device 40 is attached to the fuel cell 1. As shown in the figure, since it engages with the detection connector 41 via the conductive portion 19 exposed from the recess formed in the terminal portion 17, the engagement of the detection connector 41 can be prevented, and the cell The voltage detection reliability can be improved. Further, an increase in the thickness of the separator 9 due to the formation of the conductive portion 19 can be suppressed.

  Further, since the terminal portion 17 and the dummy terminal portion 18 are welded by laser, the rigidity of the terminal portion 17 is reinforced by the dummy terminal portion 18 without increasing the thickness of each separator 9, 10 itself. Therefore, the connection reliability with the connector 41 can be improved.

As described above, according to the fuel cell voltage detection structure of the present invention, each fuel cell is secured while ensuring the sealing performance in the communication holes 21 to 26 of the reaction gas and the cooling medium formed in the separators 9 and 10. 2 voltage detection can be performed.
Of course, the contents of the present invention are not limited to the embodiments. For example, in the embodiment, the outer peripheral portions 13 and 14 are formed by bonding resin films from the front and back, but the present invention is not limited thereto, and may be formed by, for example, injection molding. Moreover, the shape of the fuel cell 2 may be formed in, for example, a polygonal shape, a circular shape, or a square shape instead of a rectangular shape in plan view. Further, in the embodiment, the cooling medium flow path is formed for each fuel battery cell 2, but the fuel is formed so that the cooling medium flow path is formed for each of a plurality of fuel battery cells (two or more fuel battery cells). A battery may be configured.

  Moreover, as shown in FIG. 14, the planar shape of the terminal part 17 is not specifically limited, For example, it can select according to conditions, such as a square, a triangle, a pentagon, substantially Σ shape. Further, as shown in FIGS. 15 (a) and 15 (b), the terminal portion 17 formed in a concave shape can be applied to either a connector 41 having an outer shape formed in a bowl shape and hollow or solid inside. is there. And as shown to FIG.15 (c), (d), you may form so that the electroconductive part 19 may be exposed from the convex part which protrudes with respect to the resin part 20. FIG. If it does in this way, since it will engage with the connector 41 for a detection via a convex part, it will become possible to engage with the connector 41 for a detection, without contacting the resin part 20, and durability of the terminal part 17 will be sufficient as it. Can be improved, and the life can be extended.

It is a top view which shows the fuel cell in embodiment of this invention. It is a top view which shows one separator main body with which each fuel cell which comprises the fuel cell of FIG. 1 is provided. It is a top view which shows the other separator main body with which each fuel cell which comprises the fuel cell of FIG. 1 is provided. FIG. 2 is an overall plan view of one separator provided in each fuel cell constituting the fuel cell of FIG. 1. FIG. 2 is an overall plan view of the other separator provided in each fuel cell constituting the fuel cell of FIG. 1. It is a whole top view which shows the state which performed laser welding to the other separator with which one fuel battery cell is provided among each fuel battery cell. It is a whole top view which shows the state which performed laser welding to the membrane electrode structure with which one fuel battery cell is provided among each fuel battery cell. It is a whole top view which shows the state which performed laser welding to one separator with which one fuel battery cell is provided among each fuel battery cell. It is a whole top view which shows the state which performed laser welding to the other separator with which the fuel battery cell adjacent to the lower side of one fuel battery cell among each fuel battery cell. It is an enlarged plan view which shows the circumference | surroundings of the communicating hole in each separator. It is an expanded sectional view showing a flow passage formed in each separator. It is principal part sectional drawing which shows the state which attached the connector to the fuel cell. It is a disassembled perspective view which shows the flow of the reaction gas and cooling medium in each fuel cell. It is a top view which shows the modification of a terminal part. It is sectional drawing which shows the modification of a terminal part.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Fuel cell 2 ... Fuel cell 7 ... Membrane electrode structure 9, 10 ... Separator 11a, 12a ... Electrode reaction surface (electrode reaction part)
DESCRIPTION OF SYMBOLS 13, 14 ... Outer peripheral part 17 ... Terminal part 18 ... Dummy terminal part 19 ... Conductive part 20 ... Resin part 21 ... Fuel gas supply port (communication hole)
22 ... Fuel gas outlet (communication hole)
23 ... Oxidant gas supply port (communication hole)
24 ... Oxidant gas outlet (communication hole)
25 ... Cooling medium supply port (communication hole)
26 ... Cooling medium outlet (communication hole)
21a-26a ... seal part 41 ... connector

Claims (5)

Applied to a fuel cell having a fuel cell having a membrane electrode structure sandwiched between a pair of separators;
Each separator includes a metal electrode reaction part and a resin outer peripheral part provided on the outer periphery of the electrode reaction part,
A communication hole for communicating the reaction gas or the cooling medium is formed in each of the outer peripheral portions,
Around each communication hole is formed a seal part in which a resin member is melted by a laser,
Of the pair of separators, one of the separators is formed with a terminal portion protruding from the outer peripheral portion,
The terminal portion is formed by extending the electrode reaction portion, and a conductive portion formed so as to be engageable with the cell voltage detection connector at a part of one surface thereof; and a resin portion covering the periphery of the conductive portion; A fuel cell voltage detection structure comprising:   2. The fuel cell voltage detection structure according to claim 1, wherein the terminal portion is formed with a recessed portion recessed with respect to the resin portion, and the conductive portion is exposed from the recessed portion.   2. The fuel cell voltage detection structure according to claim 1, wherein the terminal portion is formed with a protruding portion that protrudes with respect to the resin portion, and the conductive portion is exposed from the protruding portion. Among the pair of separators, the other separator has a dummy terminal portion formed at a position facing the terminal portion,
The fuel cell voltage detection structure according to any one of claims 1 to 3, wherein the dummy terminal portion is formed in substantially the same shape as the terminal portion, and has an outer surface covered with a resin. . Among the fuel cells constituting the fuel cell, a terminal portion of one fuel cell, and
The fuel cell voltage detection structure according to claim 4, wherein the fuel cell adjacent to the fuel cell in the stacking direction is welded by a laser.

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