JP2006318772A - Separator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a separator for fuel cell capable of suppressing position shifting between each plates in a separator of three-layer structure. <P>SOLUTION: The separator constituting a fuel cell comprises an intermediate plate 1 having a penetrated part, a first plate 2 contacting a first face of the intermediate plate, a second plate 3 contacting the second face of the intermediate plate, a first protrusion 27 which is installed on the intermediate plate side of the first plate and has a crown portion and a side portion, and a second protrusion 37 which is installed on the intermediate plate side of the second plate and has a crown portion and a side portion. The first protrusion is arranged at a position overlapping with the penetrated part of the intermediate plate viewed from lamination direction and the second protrusion is arranged at a position which overlaps with the penetrated part of the intermediate plate viewed from lamination direction and in which at least part of the side portion of the second protrusion contacts at least part of the side portion of the first protrusion. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a separator for a fuel cell, and relates to suppression of displacement of an assembly position of a separator having a three-layer structure.

  In recent years, fuel cells that generate electricity by electrochemical reaction between hydrogen and oxygen have attracted attention. As a main structure of such a fuel cell, a so-called stack structure has been developed in which a substantially flat membrane electrode assembly (MEA) and a separator are stacked and fastened in the stacking direction. 2. Description of the Related Art As a separator for a fuel cell having a stack structure, a separator having a three-layer structure composed of an anode side plate, a cathode side plate, and an intermediate plate sandwiched between both plates is known.

  In such a separator having a multilayer structure, there is a case where a positional deviation occurs between one layer constituting the separator and another layer. Such misalignment may cause deformation (for example, twist) of the separator and thus the entire fuel cell, and may cause problems such as deterioration in power generation performance and decrease in durability. As a technique for suppressing such a problem, a technique using a plate-like material sandwiched between one layer and another layer constituting a separator and an elastic protrusion fixed to the separator is known (patent) Reference 1). In this prior art, the plate-like material is slidably held with respect to one layer and the other layer by engaging an elastic protrusion with a hole provided in the plate-like material. And the deformation | transformation of the separator and the whole fuel cell is absorbed by the slidable plate-shaped material.

JP 2003-151571 A

  However, the above-described conventional technique requires separate parts such as elastic protrusions and plate-like materials, which may lead to a complicated structure and an increased number of parts. Further, it is effective if the displacement itself can be suppressed instead of (or in addition to) absorbing the deformation caused by the displacement.

  The present invention has been made in order to solve the above-described problems, and an object of the present invention is to suppress misalignment between plates in a separator having a three-layer structure.

  In order to solve the above-mentioned problems, the present invention provides a separator that is laminated with a membrane electrode assembly sandwiched therebetween and constitutes a fuel cell. The separator according to the present invention has a first surface and a second surface, an intermediate plate having a through portion penetrating in the thickness direction, and a first plate abutting on the first surface of the intermediate plate A second plate abutting against the second surface of the intermediate plate, a first projecting portion provided on the intermediate plate side of the first plate and having a top and a side, and A second projecting portion provided on the intermediate plate side of the second plate and having a top portion and a side portion, and the first projecting portion of the intermediate plate as viewed from the direction of the stacking. The second projecting portion is disposed at a position overlapping the penetrating portion, and the second projecting portion overlaps with the penetrating portion of the intermediate plate when viewed from the stacking direction, and at least a part of a side portion of the second projecting portion. Is in contact with at least a part of the side of the first protrusion. Characterized in that it is arranged at a position.

  In the separator according to the present invention, since at least a part of the side portion of the first projecting portion and at least a part of the side portion of the second projecting portion are in contact, the first plate and the second plate It can suppress that a plate shifts relatively.

  In the separator according to the present invention, the first protruding portion is a first hook-shaped portion having a convex shape in cross section, and the second protruding portion has a convex shape in cross section. It may be a second hook-shaped part parallel to the first hook-shaped part. In this case, the first plate and the second plate are prevented from being relatively displaced by abutting between the first hook-shaped portion and the second hook-shaped portion parallel to the first hook-shaped portion. can do.

  In the separator according to the present invention, a plurality of combinations of the first projecting portion and the second projecting portion with which the side portions abut against each other are provided, and the first projecting portion is You may arrange | position to an outer peripheral side rather than a 2nd protrusion part. By providing a plurality of sets of the first protrusions and the second protrusions in this manner, it is possible to more reliably suppress relative displacement between the first plate and the second plate.

  In the separator according to the present invention, the second projecting portion is a projecting portion having a convex shape in cross section, and the first projecting portion has a recessed portion into which the projecting portion is fitted. Also good. If it carries out like this, it can suppress that a 1st plate and a 2nd plate shift | deviate relatively by fitting a 1st protrusion part and a recessed part.

  In the separator according to the present invention, the first plate is an anode plate that contacts the anode side of the membrane electrode assembly when the fuel cell is configured, and the second plate is the fuel cell. When configured, it may be a cathode plate that contacts the cathode side of the membrane electrode assembly. By so doing, it is possible to more reliably prevent the first plate and the second plate from being relatively displaced due to thermal expansion of the anode plate and the cathode plate during the operation of the fuel cell.

  Hereinafter, a separator according to the present invention will be described based on examples with reference to the drawings.

A. First embodiment:
With reference to FIGS. 1-3, the structure of the separator which concerns on 1st Example of this invention and the fuel cell containing a separator is demonstrated. FIG. 1 is an explanatory diagram showing the configuration of the fuel cell in the first embodiment. FIG. 2 is a front view and a sectional view of the separator according to the first embodiment. The right half of FIG. 2B shows an ee cross section in FIG. Moreover, the left half of FIG.2 (b) has shown the ff cross section in Fig.2 (a). In FIG. 2B, the thickness in the stacking direction of each constituent member is shown approximately twice that of FIG. FIG. 3 is a front view and a cross-sectional view of the BB portion in FIG.

  The fuel cell 1000 is configured by alternately laminating the seal-integrated membrane electrode assembly 200 and the separator 100.

  The seal-integrated membrane electrode assembly 200 includes a membrane electrode assembly 50 and a seal member 60. The seal member 60 is formed of a material having gas impermeability, elasticity, and heat resistance, such as silicone rubber. As shown by a broken line in FIG. 1, a hole 65 for arranging the membrane electrode assembly 50 is provided at the center of the seal member 60. The membrane electrode assembly 50 includes an electrolyte membrane 4, an anode 5, and a cathode 6. The electrolyte membrane 4 is an ion exchange membrane formed of, for example, a fluorine-based resin material (for example, Nafion (registered trademark of DuPont)) and having good ionic conductivity in a wet state. The anode 5 and the cathode 6 are formed of a porous material (for example, a metal porous body) having gas diffusibility and conductivity. The anode 5 and the cathode 6 carry platinum or an alloy made of platinum and other metals as a catalyst for the fuel cell reaction.

  The separator 100 includes an intermediate plate 1, a cathode plate 2, and an anode plate 3. Stainless steel is used for these three plates. Instead of stainless steel, various materials having gas impermeability and conductivity, for example, other metal materials, specifically, titanium, titanium alloy, or the like may be used. The anode plate 3 is in contact with one surface (hereinafter also referred to as a first surface) of the intermediate plate 1, and the cathode plate 2 is also referred to as the other surface (hereinafter also referred to as a second surface) of the intermediate plate 1. .). The anode plate 3 and the intermediate plate 1, and the cathode plate 2 and the intermediate plate 1 are joined at a contact surface by using a predetermined joining method, for example, thermocompression bonding, brazing, or welding.

  In the separator 100, various fluid flow paths are formed by through holes provided in the intermediate plate 1, the cathode plate 2, and the anode plate 3, respectively. That is, as shown in FIG. 2, the fuel gas is formed as a flow path for supplying fuel gas to the anode 5 as a fuel gas supply manifold 130 that passes through the three plates and a through hole that passes through the intermediate plate 1. A fuel gas supply hole 33 formed as a through hole penetrating the supply flow path 13 and the anode plate 3 is formed. Similarly, a fuel gas discharge manifold 140, a fuel gas discharge flow path 14, and a fuel gas discharge hole 34 for discharging the fuel gas are formed.

  Further, the separator 100 has an oxidizing gas supply manifold 110, an oxidizing gas supply channel 11 that penetrates the intermediate plate 1, and an oxidizing gas supply hole that penetrates the cathode plate 2 as a channel for supplying oxidizing gas to the cathode 6. 21 is formed. Similarly, an oxidizing gas discharge manifold 120 for discharging the oxidizing gas, an oxidizing gas discharge channel 12, and an oxidizing gas discharge hole 22 are formed. Further, a cooling medium supply manifold 150, a cooling medium flow path 15, and a cooling medium discharge manifold 160 are formed as flow paths for supplying / discharging a cooling medium flow path for cooling the fuel cell 1000. In FIG. 2A, the hatched portions represent the various manifold portions described above.

  The flow of the fuel gas will be described with reference to FIG. The fuel gas is supplied from the fuel gas supply manifold 130 to the anode 5 through the fuel gas supply passage 13 and the fuel gas supply hole 33 as indicated by an arrow on the left side of FIG. The fuel gas supplied to the anode 5 is used in the fuel cell reaction while flowing through the porous anode 5. Then, the used fuel gas is discharged from the anode 5 to the fuel gas discharge manifold 140 through the fuel gas discharge hole 34 and the fuel gas discharge passage 14 as indicated by an arrow on the right side of FIG. .

  Although the illustration of the cross section in the flow path of the oxidizing gas (the gg cross section in FIG. 2A) is omitted, it is the same as the cross section shown in FIG. 2B (the ee cross section and the ff cross section). It has a structure. The oxidizing gas is supplied from the oxidizing gas supply manifold 110 through the oxidizing gas supply channel 11 and the oxidizing gas supply hole 21 to the cathode 6 and used for the fuel cell reaction. The used oxidizing gas is discharged to the oxidizing gas discharge manifold 120 through the oxidizing gas discharge hole 22 and the oxidizing gas discharge channel 12.

  The cooling medium flows from the cooling medium supply manifold 150 into the cooling medium flow path 15 and is discharged from the cooling medium flow path 15 to the cooling medium discharge manifold 160. The cooling medium mainly cools the fuel cell 1000 while flowing in the cooling medium flow path 15.

  The separator 100 further includes four structures MC (hereinafter, referred to as “displacement suppressing structures”) for suppressing relative displacement between the cathode plate 2 and the anode plate 3. The region where the displacement suppressing structure MC is disposed is a region where the above-described various fluid flow paths are not formed, and a region facing the above-described membrane electrode assembly 50 when the fuel cell 1000 is configured. (Hereinafter referred to as a power generation region) This is a region other than 55. In the present embodiment, as shown in FIG. 2, they are arranged at the four outer corners of the quadrangular separator 100 on the outer peripheral portion outside the power generation region 55.

  As shown in FIG. 2, the four shift suppressing structures MC are divided into two arranged on one diagonal line BB of the separator 100 and two arranged on the other diagonal line AA. . The two displacement suppression structures MC arranged on the diagonal line BB suppress the relative displacement between the cathode plate 2 and the anode plate 3 in the diagonal line BB direction. On the other hand, the two displacement suppression structures MC arranged on the diagonal line AA suppress the relative displacement between the cathode plate 2 and the anode plate 3 in the diagonal line AA direction.

  With reference to FIG. 3, the shift suppression structure MC will be described in more detail. The upper diagram in FIG. 3 shows a front view of the BB portion in FIG. 2, and the lower diagram in FIG. 3 shows a BB cross section in the upper diagram in FIG. However, in FIG. 3, portions other than the corner portion where the shift suppression structure MC is arranged, that is, the central portion of the separator 100 is omitted for easy viewing of the drawing. The shift suppressing structure MC is constituted by a through-hole 17 formed in the intermediate plate 1, a first hook-like part 37 formed in the anode plate 3, and a second hook-like part 27 formed in the cathode plate 2. Composed.

  As shown in FIG. 3, the penetration portion 17 forms a space SP between the cathode plate 2 and the anode plate 3 when the three plates are joined to form the separator 100 (hereinafter referred to as joining). To do. As shown in FIG. 3, the first hook-shaped portion 37 protrudes to the side of the anode plate 3 that contacts the intermediate plate 1 during bonding. The first hook-shaped portion 37 has a hook-like shape in which the cross section has a convex shape in the short side direction (the direction parallel to the diagonal line BB in the upper diagram of FIG. 3). As shown in FIG. 3, the second hook-shaped portion 27 has the same shape as the first hook-shaped portion 37. In other words, the second hook-shaped portion 27 protrudes to the side of the cathode plate 2 that contacts the intermediate plate 1 during bonding. The second bowl-shaped portion 27 has a bowl-like shape in which the cross section in the short side direction (the direction parallel to the diagonal line BB in the upper diagram of FIG. 3) has a convex shape. The longitudinal direction of the first hook-shaped portion 37 (the direction perpendicular to the diagonal line BB in the upper diagram of FIG. 3) and the longitudinal direction of the second hook-shaped portion 27 are parallel to each other. The through portion 17 is formed by punching the intermediate plate 1, for example. The first hook-shaped portion 37 and the second hook-shaped portion 27 are formed by, for example, pressing the anode plate 3 and the cathode plate 2.

  Both the first hook-shaped part 37 and the second hook-shaped part 27 are formed at positions where they overlap with the penetrating part 17 formed in the intermediate plate 1 at the time of joining. Therefore, the first hook-like portion 37 and the second hook-like portion 27 protrude into the space SP described above at the time of joining. The first hook-shaped portion 37 and the second hook-shaped portion 27 are in contact with each other at a part of the side portions in the space SP. In FIG. 3, symbol TP indicates a contact portion between the first hook-shaped portion 37 and the second hook-shaped portion 27. Here, the side part of the first hook-shaped part 37 is a part other than the top PP of the first hook-shaped part 37, in other words, a part that is not parallel to the other part (flat part) of the anode plate 3. Refers to that. The same applies to the side portion of the second bowl-shaped portion 27.

  Here, the first hook-shaped portion 37 formed on the anode plate 3 is arranged on the outer peripheral side from the second hook-shaped portion 27 formed on the cathode plate 2. That is, as shown in FIG. 3, the second hook-shaped portion 27 formed on the cathode plate 2 is disposed on the center side (inside) of the separator 100 on the diagonal line BB, and is formed on the anode plate 3. The first hook-shaped part 37 is disposed outside the separator 100.

  The two displacement suppression structures MC disposed on the diagonal line AA (see FIG. 2) have the same configuration as the two displacement suppression structures MC disposed on the diagonal line BB described above. Therefore, detailed description is omitted.

  According to the separator 100 according to the first embodiment described above, since the four shift suppressing structures MC are provided, it is possible to suppress the cathode plate 2 and the anode plate 3 from being relatively shifted. As a result, it is possible to suppress the deformation of the separator 100 and the fuel cell 1000 as a whole, and to suppress the performance deterioration of the fuel cell 1000 due to such deformation. Moreover, since positioning becomes easy, the assembling accuracy at the time of assembling the fuel cell and the assembling efficiency are improved.

Furthermore, since the first hook-like portion 37 formed on the anode plate 3 is arranged on the outer peripheral side from the second hook-like portion 27 formed on the cathode plate 2, during operation of the fuel cell 1000, It can suppress that a clearance gap produces in contact part TP of the 2nd bowl-shaped part 27 and the 1st bowl-shaped part 37. FIG. That is, the calorific value associated with the cathode reaction (eg, 2H ⁺ + 2e ⁻ + (1/2) O ₂ → H ₂ O) of the fuel cell is the calorific value associated with the anode reaction (eg, H ₂ → 2H ⁺ + 2e ⁻ ). is more than. Therefore, the amount of thermal expansion of the cathode plate 2 during operation of the fuel cell is larger than the amount of thermal expansion of the anode plate 3. As a result, the thermal expansion accompanying the heat generated by the electrochemical reaction generates a pressure that strengthens the contact of the contact portion TP between the first hook-like portion 37 and the second hook-like portion 27, and effectively suppresses the deviation. be able to. For example, in the case where the fuel cell 1000 is used as a power source for an automobile, it is possible to effectively suppress deviation due to vibration or impact during driving.

  As described above, the first hook-like portion 37 and the second hook-like portion 27 constituting the shift suppressing structure MC are formed by pressing the anode plate 3 and the cathode plate 2, and the penetrating portion 17 is an intermediate plate. It is formed by stamping 1. As a result, the misalignment suppressing structure MC can be manufactured using an easy and highly productive processing method. Further, the number of parts does not increase due to the shift suppression structure MC. In addition, since the separator is made of a thin plate, even if it is difficult to provide a structure for suppressing displacement (such as a recess) by cutting or the like, the structure for suppressing displacement can be easily provided.

  Furthermore, since the 1st collar-shaped part 37 and the 2nd collar-shaped part 27 are formed in the intermediate | middle plate 1 side (the penetration part 17 side of the intermediate | middle plate 1), the enlargement of a separator can be suppressed.

B. Second embodiment:
With reference to FIG. 4 and FIG. 5, the structure of the separator based on 2nd Example of this invention is demonstrated. FIG. 4 is a front view of the separator according to the second embodiment. 5 is a front view and a cross-sectional view of the CC portion in FIG. FIG. 4 shows only the shift suppression structure MC2 in the second embodiment. Since other structures formed in the separator 100 are the same as those in the first embodiment, the illustration is omitted. In FIG. 5, the upper left figure shows a front view of the CC portion, the upper right figure shows a DD section of the upper left figure, and the lower figure shows a CC section of the upper left figure.

  The shift suppression structure MC2 according to the second embodiment is arranged at two locations. In the present embodiment, as shown in FIG. 4, the shift suppression structure MC <b> 2 is disposed at two corner portions of the quadrangular separator 100 that face each other. The shift suppression structure MC2 is formed by the through portion 18 formed in the intermediate plate 1, the fitting portion 38 formed in the anode plate 3, and the protrusion 28 formed in the cathode plate 2.

  The penetration part 18 forms a space SP2 between the cathode plate 2 and the anode plate 3 at the time of joining, like the penetration part 17 in the first embodiment. The protrusion 28 is a protrusion having a convex cross section and a circular shape in front view. The protrusion 28 protrudes to the side of the cathode plate 2 that comes into contact with the intermediate plate 1 at the time of joining. As a whole, the fitting part 38 protrudes to the side in contact with the intermediate plate 1 at the time of joining. As shown in FIG. 5, a recess (hereinafter referred to as a concave portion) 381 for fitting the projection 28 described above at the time of joining is formed in the central portion of the fitting portion 38. Similar to the first embodiment, the penetrating portion 18 is formed, for example, by punching the intermediate plate 1, and the protruding portion 28 and the fitting portion 38 are, for example, press-working the cathode plate 2 and the anode plate 3. Formed by.

  Both the projecting portion 28 and the fitting portion 38 are formed at a position overlapping the through portion 18 formed in the intermediate plate 1 at the time of joining. Therefore, the protrusion 28 and the fitting portion 38 protrude into the space SP2 described above at the time of joining. A part of the side part of the protrusion part 28 and a part of the side part of the concave part 381 formed in the fitting part 38 are in contact with each other in the space SP2. In FIG. 5, symbol TP <b> 2 indicates a contact portion between the protrusion 28 and the fitting portion 38. Here, the side part of the protrusion part 28 refers to a part other than the top PP2 of the protrusion part 28, that is, a part not parallel to the other part (flat part) of the cathode plate 2. Further, the side portion of the concave portion 381 refers to a portion other than the bottom portion BP of the concave portion 381, that is, a portion that is not parallel to the other portion (flat portion) of the anode plate 3.

  According to the separator 100 according to the second embodiment described above, the same effects as in the first embodiment can be obtained. Furthermore, according to the separator 100 according to the second embodiment, there is an advantage that the shift can be suppressed with only the two shift suppression structures MC2.

C. Variations:
-1st modification In the 1st example, four shift control structures MC are arranged, and in the 2nd example, two shift control structures MC2 are arranged, but the number arranged is limited to the above-mentioned example. I can't. For example, a configuration in which three shift suppression structures MC according to the first embodiment are arranged is also possible. FIG. 6 is a front view of a separator according to a first modification. In FIG. 6, only the shift suppression structure MC is illustrated. It is assumed that other structures formed in the separator 100 are appropriately disposed in a portion where the shift suppressing structure MC is not disposed. As shown in FIG. 6, for example, the shift suppression structure MC is arranged at positions corresponding to the three corners of the regular triangle TR. And the longitudinal direction of the 1st hook-shaped part 37 and the 2nd hook-shaped part 27 which comprise each shift | offset | difference suppression structure MC is arrange | positioned in parallel with the opposite side of the corner | angular part where the hook-shaped parts 27 and 37 are arrange | positioned. . In this way, the three shift suppressing structures MC may be arranged in a well-balanced manner to suppress the shift.

Second Modification In the first embodiment, the second hook-shaped portion 27 and the first hook-shaped portion 37 have a straight hook shape when viewed from the front, but have other shapes when viewed from the front. You may do it. For example, the first hook-shaped portion 37 and the second hook-shaped portion 27 may be formed in an arc shape in a front view, or may be formed in a dogleg shape.

  As mentioned above, although the Example and modification of this invention were demonstrated, this invention is not limited to these Example and modification at all, and implementation in a various aspect is possible within the range which does not deviate from the summary. It is.

It is explanatory drawing which shows the structure of the fuel cell in 1st Example. It is the front view and sectional drawing of the separator which concern on 1st Example. It is the front view and sectional drawing of the BB part in FIG. It is a front view of the separator which concerns on 2nd Example. It is the front view and sectional drawing of CC part in FIG. It is a front view of the separator which concerns on a 1st modification.

Explanation of symbols

1 ... intermediate plate 2 ... cathode plate 3 ... anode plate 4 ... electrolyte membrane 5 ... anode 6 ... cathode 11 ... oxidation gas supply flow path 12 ... oxidation gas discharge Flow path 13 ... Fuel gas supply flow path 14 ... Fuel gas discharge flow path 15 ... Cooling medium flow path 17, 18 ... Penetration part 21 ... Oxidation gas supply hole 22 ... Oxidation gas Discharge hole 27 ... second hook-like portion 28 ... protrusion 33 ... fuel gas supply hole 34 ... fuel gas discharge hole 37 ... first hook-like portion 38 ... fitting Part 381 ... Concave part 50 ... Membrane electrode assembly 55 ... Power generation region 60 ... Seal member 100 ... Separator 110 ... Oxidizing gas supply manifold 120 ... Oxidizing gas discharge manifold 130. ..Fuel gas supply manifold 140 ... Fuel gas discharge manifold 150 ... Cooling medium supply manifold 160 ... Cooling medium discharge manifold 200 ... Integrated seal Mold membrane electrode assembly 1000 ... Fuel cell MC, MC2 ... Suppression control structure

Claims (5)

A separator that is laminated with a membrane electrode assembly sandwiched therebetween to constitute a fuel cell,
An intermediate plate having a first surface and a second surface and having a penetrating portion penetrating in the thickness direction;
A first plate abutting against the first surface of the intermediate plate;
A second plate in contact with the second surface of the intermediate plate;
A first protrusion provided on the intermediate plate side of the first plate and having a top and a side;
A second protrusion provided on the intermediate plate side of the second plate and having a top and a side;
With
The first projecting portion is disposed at a position overlapping with the through portion of the intermediate plate when viewed from the stacking direction.
The second projecting portion overlaps the penetrating portion of the intermediate plate when viewed from the stacking direction, and at least a part of a side portion of the second projecting portion is on the side of the first projecting portion. Separator disposed at a position in contact with at least a part of the part. The separator according to claim 1,
The first protrusion is a first hook-shaped section having a convex shape in cross section;
The second protrusion is a separator having a convex shape in cross section and a second hook-like part parallel to the first hook-like part. The separator according to claim 1 or 2,
A plurality of combinations of the first projecting portion and the second projecting portion with which the side portions abut each other are provided,
The first projecting portion is a separator disposed on the outer peripheral side from the second projecting portion. The separator according to claim 1,
The second protrusion is a protrusion having a convex cross section,
The first projecting portion is a separator having a recessed portion into which the projecting portion is fitted. In the separator according to claim 3 or claim 4,
The first plate is an anode plate that contacts the anode side of the membrane electrode assembly when the fuel cell is configured;
The second plate is a separator that is a cathode plate that contacts the cathode side of the membrane electrode assembly when the fuel cell is configured.

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