JP2003203644A - Metal separator and fuel cell using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a metal separator that is made of a sheet of a metal thin plate and has a different gas channel on its surface and rear face, and has small electric resistance, and a fuel cell using the same. <P>SOLUTION: This is a metal separator 1 which is made of a metal thin plate having a surface 2a and a rear face 2b and comprises concavo-convex parts 3a, 3b in which convex ridges 4a, 4b and concave grooves 6a, 6b having a cross section of nearly trapezoid with the surface 2a of concave or convex shape and the rear face 2b of convex or concave shape are formed alternately in parallel in plural pieces, and a pair of headers 7a, 7b that cross at right angles these concave grooves 6a, 6b and the convex ridges 4a, 4b at the both ends in the longitudinal direction of the plural concave grooves 6a, 6b of these concavo-convex parts 3a, 3b, and are made shallower than the depth of the above concave grooves 6a, 6b and lower than the height of the above convex ridges 4a, 4b. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a metal separator and a solid polymer electrolyte fuel cell using the same (hereinafter,
Simply referred to as a fuel cell).

[0002]

2. Description of the Related Art A fuel cell, as shown in FIG.
Metal separators 72 are laminated on both sides of the solid polymer film 70, and a sealing material (not shown) is sandwiched and fixed between these peripheral portions. The solid polymer film 70 has positive electrode and negative electrode catalyst electrodes arranged on both sides of the electrolyte membrane, and a gas diffusion electrode (not shown) made of carbon paper, carbon cloth, or the like disposed on them. In addition, the metal separator 72
Is a negative electrode side substrate 74 having a plurality of concave grooves 75 and a positive electrode side substrate 7 having a plurality of concave grooves 79, as shown in FIG.
8 is laminated such that the concave groove 75 and the concave groove 79 are orthogonal to each other and their bottom surfaces are in surface contact with each other.

The negative electrode / positive electrode side substrates 74, 78 are of the same size and shape. When the former is taken as an example, a plurality of substrates are provided at positions excluding the peripheral portion of the metal thin plate 74a, as shown in FIG. 10C, for example. Of the recessed grooves 75, a plurality of protrusions 77 located between the recessed grooves 75, and header grooves 76, 76 that connect both ends of the recessed grooves 75 in the longitudinal direction. The negative electrode-side substrate 74 as described above is formed by pressing a flat metal thin plate 74a so that the plurality of concave grooves 7 are formed.
5, a plurality of ridges 77, and a header groove 76 are integrally formed. As shown in FIG. 10B, the negative electrode side substrate 7
On the bottom surface side of the metal thin plate 74a of No. 4, a convex strip 75a having a shape following the sectional shape of the concave groove 75 and the header groove 76, and a convex strip 7a.
7 and a concave groove 77a having a shape following the cross-sectional shape of No. 7 are formed. In addition, the shapes of the front and back surfaces are the same as the positive substrate 78.
Is also the same.

In the negative electrode side substrate 74, fuel gas as a negative electrode active material is supplied from a supply hole (not shown) opened in one of the header grooves 76, and the fuel gas is divided into a plurality of concave grooves 75, and then the other header groove. It is discharged from a discharge hole (not shown) opened at 76. The fuel gas comes into contact with the catalyst electrode on the negative electrode side in the adjacent solid polymer film 70 while flowing through the recessed grooves 75, and the hydrogen contained in the fuel gas is divided into hydrogen ions and electrons. . The hydrogen ions penetrate the electrolyte (liquid) of the solid polymer film 70, and the electrons are sent to the positive electrode side catalyst electrode through an external circuit (not shown). Further, in the positive electrode side substrate 78, the oxidant gas that is the positive electrode active material is circulated in the same manner as described above, and contacts the positive electrode side catalyst electrode in the adjacent solid polymer film 70 while flowing in each groove 79. Then, oxygen, hydrogen ions, and electrons react to generate water.

[0005]

However, as shown in FIG. 10 (A), the metal separator 72 sandwiched between the plurality of solid polymer membranes 70, 70 is composed of two metal separators. Since the side substrates 74 and 78 are laminated, there are problems that the number of constituent members of the fuel cell increases, the assembly thereof becomes complicated, and the thickness of the entire fuel cell obtained becomes excessive. In addition, the negative electrode side substrate 7
4 has a small contact area between the ridge 77 and the ridge of the positive electrode side substrate 78, there is also a problem that the resistance of the current flowing between the vertically adjacent solid polymer films 70, 70 along the thickness direction increases. It was The present invention solves the problems in the conventional techniques described above, and a metal separator made of a single metal thin plate having different gas flow passages on the front surface and the back surface thereof and having a low electric resistance, and An object is to provide a used fuel cell.

[0006]

In order to solve the above-mentioned problems, the present invention uses uneven portions formed on the front surface and the back surface of a single metal thin plate as gas flow passages, and a fuel gas and an oxidizer are provided in these passages. To allow the gas to flow evenly,
It was made with an inspiration. That is, the first metal separator (Claim 1) of the present invention is a cross section in which a plan view is a substantially rectangular metal thin plate having a front surface and a back surface, and the front surface is a concave portion or a convex portion and the back surface is a convex portion or a concave portion. Is a substantially quadrangular or trapezoidal concave and convex portions alternately formed in parallel with a plurality of concave and convex portions, at the longitudinal ends of the plurality of concave and convex portions of such concave and convex portion, orthogonal to the concave groove and the convex ridge, And a pair of header portions that are shallower than the depth of the groove and lower than the height of the protrusion.

According to this, the plurality of recessed grooves in the concavo-convex portion formed on the front surface and the back surface of one sheet of metal serve as parallel flow passages for the fuel gas or the oxidant gas, respectively.
The front surface and the back surface can be utilized as either the positive or negative electrode side substrate or the negative electrode side substrate. For this reason, it is possible to utilize as a metal separator having a small electric resistance by forming one metal thin plate by a press or the like without using the two positive electrode side / negative electrode side substrates in the related art. The front surface and the back surface of the metal thin plate are relative names, and refer to either one surface of the metal thin plate and the surface on the opposite side. Further, since the height of the header portion is smaller than the header groove in the conventional positive electrode side / negative electrode side substrate of the two-sheet structure, the width of the header portion is set wider than in the conventional case.

Further, according to the present invention, the depth of the groove and the height of the ridge are substantially the same along the outer sides of the pair of header portions provided at both ends in the longitudinal direction of the plurality of grooves of the uneven portion. Metal separator with thick sealing material
(Claim 2) is also included. According to this, the header portion located at both ends of each uneven portion on the front surface and the back surface of the metal thin plate is a closed space, and without leaking the fuel gas or the oxidant gas between the adjacent solid polymer film, The reaction such as hydrogen ionization and electronization can be caused by flowing in the groove of each uneven portion.

On the other hand, a second metal separator of the present invention (claim 3) is a thin metal plate having a substantially rectangular shape in plan view and having a front surface and a back surface, the front surface being a concave portion or a convex portion and the back surface being a convex portion or a concave portion. Between a plurality of concave grooves and a plurality of convex stripes each having a substantially quadrangular or trapezoidal cross section and formed in parallel with each other, between one end of the concave grooves and the convex stripes and one side or the other side of the thin metal plate. , A plurality of bypass passages that are shallower than the depth of the concave groove and lower than the height of the convex stripe, and the other ends of the concave groove and the convex stripe are one side of the metal thin plate or It is characterized in that the plurality of bypass passages are alternately arranged in opposite directions in a plan view while reaching the other side.

According to this, the plurality of concave grooves formed on the front surface and the back surface of one sheet of metal and the bypass passages alternately located at one end of these concave grooves of the fuel gas or the oxidant gas exhibiting a zigzag shape. To provide a single flow path for Therefore, the reaction of each of the above-mentioned gases flowing in the zigzag shape can be reliably performed, and the front surface and the back surface can be utilized as either the positive or negative electrode side substrate or the negative electrode side substrate.
Therefore, even the second metal separator can be used as a metal separator having a small electric resistance by using one metal thin plate by press molding or the like without using the two positive electrode side / negative electrode side substrates. The gas inlets and outlets are located near the ends of the recessed grooves at both ends, and are also arranged at diagonal positions in the thin metal plate or at both ends on the same side. Further, the width of the bypass passage is set to be equal to or larger than the width of the concave groove.

Further, according to the present invention, the depth of the concave groove and the convex stripe are formed so as to surround the metal thin body along the outer side of the plurality of bypass passages and the concave groove or the convex stripe. A metal separator (claim 4) in which a sealing material having a thickness substantially the same as the height is arranged is also included. According to this, it is possible to reliably shield the zigzag gas flow passage that surrounds the plurality of bypass passages and the groove or the ridge at both ends from the outside.

Furthermore, the present invention also includes a metal separator (claim 5) in which the metal thin plate comprises a metal base material and a thin film layer made of a noble metal coated on the front and back surfaces of the metal base material. Be done. According to this, the front surface and the back surface are coated with a thin film layer made of a noble metal having excellent corrosion resistance,
A metal separator is formed from a thin metal plate in which a metal base material having excellent moldability and required strength is located between them. For this reason, it becomes possible to provide a metal separator which is composed of only one metal thin plate and which is excellent in corrosion resistance and durability at low cost.

In addition, according to the present invention, the metal base material is made of a simple substance of Fe, Ni, Ti, Cu or Al, or an alloy based on any one of them, and the thin film layer of the noble metal is Au. Separator made of a simple substance of Ag, Ag, Pt, or Pd, an alloy based on any of these, or an alloy of two or more of the above noble metals.
(Claim 6) is also included. According to this, it becomes possible to obtain a metal separator which is composed of only one metal thin plate as described above and has excellent corrosion resistance at an optimum cost.

In addition, the fuel cell of the present invention (claim 7) is
The above-mentioned metal separators are arranged in parallel one by one between a plurality of solid polymer membranes arranged in parallel to each other and at both ends thereof. According to this, since the metal separator is composed of one metal thin plate, it is possible to provide a fuel cell which can be made compact by making the entire thickness thin, and which can obtain a stable operation at low cost. In addition, in the fuel cell of the present invention,
It is also possible to include a fuel cell in which the above-mentioned metal separators are arranged in parallel one by one between at least two solid polymer membranes parallel to each other and on both end sides thereof.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, preferred embodiments for carrying out the present invention will be described with reference to the drawings. 1 (A), (B), and FIG.
(A) and (B) are the 1st metal separator 1 in this invention.
2 shows a front surface 2a and a back surface 2b. The metal separator 1 is made of, for example, a single thin metal plate made of a stainless steel plate or the like and having a rectangular plan view, and its surfaces 2a are parallel to each other as shown in FIGS. 1 (A) and 2 (A). An uneven portion 3a including a plurality of ridges 4a and a plurality of recessed grooves 6a alternately located between the ridges 4a is provided in the central portion. Also,
A pair of header portions 7a orthogonal to these are provided at both ends in the longitudinal direction of the plurality of ridges 4a and the groove 6a. The header portions 7a may be deepened in the vicinity of the gas outlet / inlet 9a and shallower in the opposite side.

Further, as shown in FIGS. 1B and 2B, the back surface 2b of the metal separator 1 also has a plurality of ridges 4b parallel to each other and a plurality of ridges 4b located alternately between the ridges 4b. An uneven portion 3b composed of the concave groove 6b is provided in the central portion, and a pair of header portions 7b orthogonal to the convex stripes 4b and the concave groove 6b are provided at both ends in the longitudinal direction. still,
Each header portion 7b may be deepened in the vicinity of the gas outlet / outlet 9b, and may be formed shallower on the opposite side. Again,
In FIGS. 1 (A) and 1 (B), the ridges 4a and 4b are indicated by thick lines and the grooves 6a and 6b are indicated by thin lines for convenience.

1A which is an end face taken along line aa in FIG. 1A and FIG. 1B which is an end face taken along line bb in FIG. 1B. 3 is an end view of the metal separator 1 cut at the same position. FIG. As shown in FIGS. 1 (a) and 1 (b), the back side of the ridges 4a on the front surface 2a has a concave groove 6b on the back surface 2b.
And both are formed in a position that is a backside of the front and back. Further, the back side of the concave groove 6a on the front surface 2a is a convex strip 4b on the back surface 2b, and both are formed at positions where both front and back sides are integrated. As shown in FIG. 1 (α), the ridge 4
The a, the concave groove 6a, etc. may be an uneven portion 3α composed of a convex ridge 4α and a concave groove 6α each having a semicircular round end.

That is, as shown in FIGS. 2 (A) and 2 (B), the ridge 4a has a groove 6b having a trapezoidal cross section on the front surface 2a and a trapezoidal cross section on the back surface 2b. Become.
Further, the concave groove 6a is a concave portion having a trapezoidal cross section on the front surface 2a and a convex portion 4 having a trapezoidal cross section on the back surface 2b.
b. The widths of the groove 6a and the groove 6b may be different. For example, when the fuel gas is hydrogen and the oxidant gas is oxygen, the ratio of the flow channel widths of both is set to 2: 1, and when the fuel gas is hydrogen and the oxidant gas is air, the ratio of the flow channel widths of both is set to 2: 1. The widths of the concave grooves 6a and 6b are set so as to be set to: 5.

As shown in FIGS. 2 (A) and 2 (B), the concavo-convex portions 3a, 3b and the pair of header portions 7a, 7b are surrounded by the respective header portions 7a, 7b. The peripheral portions 2c and 2d extending at the same level are surrounded. Further, as shown in FIGS. 1 (a), (b) and FIGS. 2 (A), (B), the header portions 7a, 7b are lower than the height of the ridges 4a, 4b and have the grooves 6a, 6b. It is provided at a position shallower than the depth. Specifically, the header portions 7a and 7b are at a level that is approximately half the height of the ridges 4a and 4b and approximately half the depth of the concave grooves 6a and 6b. Therefore, the width of the header portions 7a and 7b is set to be slightly wider than that of the conventional one.

As shown in FIGS. 1A and 1B, a substantially square frame-shaped sealing material (gasket) 10 is arranged around the metal separator 1. Such sealing material 10
Is an integrally molded body made of synthetic rubber having elasticity such as chloroprene rubber, and the metal separator 1 is provided in the slit 12 provided at the center of the inner peripheral surface in the thickness direction.
The peripheral portions 2c and 2d are closely fitted to each other. Also,
An inlet 9a and an outlet 9a for fuel gas such as hydrogen are provided on the front surface 2a inside or part of the sealing material 10, and an inlet 9b for oxidant gas such as oxygen is provided on the rear surface 2b side.
・ Open Exit 9b. Further, a through hole 13 for a bolt is formed in the center of each side of the seal material 10 so as to penetrate and connect the seal material 10 in which the same metal separators 1 arranged adjacent to each other are fitted inside. ing.
The thickness of the sealing material 10 is, as shown in FIGS. 1 (a) and 1 (b), the height of each ridge 4a on the front surface 2a and each ridge 4 on the back surface 2b.
The difference between the height and the height of b is almost the same as or slightly thicker than this difference. Since the fuel cell is assembled, this thickness matches the thickness (difference) between the ridges 4a and 4b when the sealing material 10 is elastically deformed. Further, the sealing material 10 is formed with an inlet wi and an outlet wa of the cooling water.

3A and 3B show a front surface 2a and a back surface 2b of a metal separator 1a having different shapes. The metal separator 1a is also made of a single metal thin plate made of a stainless steel plate or the like, and its surface 2a has a plurality of ridges 4c parallel to each other and the ridges 4c as shown in FIG. 3 (A).
Concavo-convex portion 3 including a plurality of concave grooves 6c alternately located between
A header portion 7 which has a central portion c and is orthogonal to the plurality of ridges 4c and the concave grooves 6c in the longitudinal direction.
a and 7a are provided. Further, as shown in FIG. 3B, the back surface 2b of the metal separator 1a also has a concavo-convex portion made up of a plurality of parallel ridges 4d and a plurality of recessed grooves 6d alternately located between the ridges 4d. 3d is provided in the central portion, and header portions 7b, 7b orthogonal to these are provided at both ends in the longitudinal direction of the plurality of convex stripes 4d and concave grooves 6d.

As shown in FIGS. 3A and 3B, the ridge 4
c is a concave groove 6 having a U-shaped (square) cross section on the front surface 2a and a U-shaped (square) cross section on the back surface 2b.
It becomes d. Further, the concave groove 6c is a concave portion having a U-shaped (square) cross section on the front surface 2a and a U-shaped cross section on the back surface 2b.
The convex strip 4d has a (square) convex portion. Incidentally, FIG.
As shown in (A) and (B), around the uneven portions 3c, 3d and the header portions 7a, 7b, a peripheral portion 2c extending at the same level as the header portions 7a, 7b so as to surround them, Two
It is surrounded by d. In addition, the ridges 4c and the concave grooves 6c are
Similarly to the above, the ends may be rounded convex grooves or concave grooves, and the concave grooves 6c and 6d may have different widths.

Further, the header portions 7a and 7b are shown in FIG.
As shown in (A) and (B), it is provided at a position lower than the height of the convex stripes 4c and 4d and shallower than the depth of the concave grooves 6c and 6d. Specifically, the header portions 7c and 7d are at a level that is approximately half the height of the ridges 4c and 4d and approximately half the depth of the concave grooves 6c and 6d. The metal separator 1a
The sealing material 10 shown in FIG. 1 is also fitted and arranged on the outer peripheral edges of the peripheral portions 2c and 2d in the same manner as described above.

FIG. 4 (A) shows a cross section of the metal separator 1 at the uneven portions 3a and 3b. As illustrated, the metal thin plate forming the metal separator 1 is made of, for example, SUS31.
Thickness of stainless steel such as 6L 0.01 ~ 1m
m of the metal base material 14 and a thin film layer 15 made of a noble metal on the front surface and the back surface of the metal base material 14, respectively. The thin film layer 15 has a thickness of 1 μm or less, and more preferably 100 nm.
It consists of a simple substance of Au, Ag, Pt, or Pd having the following thickness, or an alloy based on any of these, or an alloy composed of two or more of the above noble metals, for example, an Au-Ag alloy. The thin film layer 15 is formed by plating, screen printing, clad rolling, CVD treatment, or PVD treatment.
The front surface and the back surface of the metal base material 14 are covered by (vacuum deposition, sputtering, ion plating, etc.).

Further, FIG. 4B shows the metal separator 1
The cross section of the concave-convex portions 3c and 3d of a is shown, and the thin metal plate also comprises a metal base material 14 similar to the above, and a thin film layer 15 similar to the above formed from a noble metal on the front surface and the back surface thereof, respectively. The uneven portions 3a, 3b, 3c, 3d
Is formed by a plastic working using a die press (not shown), which is a thin metal plate having a three-layer structure including a metal base material 14 having a front surface and a back surface coated with a thin film layer 15.
The metal base material 14 is made of Fe, Ni, Ti, Cu,
It is made of a simple substance of Al or an alloy based on any of these, for example, the above-mentioned stainless steel, and by covering the front and back surfaces with the thin film layer 15, the corrosion resistance to fuel gas and oxidant gas described later is supplemented. .

FIG. 5A shows the metal separator 1 (1a).
FIG. 3 is a cross-sectional view showing a unit portion of a fuel cell 16 using
As shown in FIG. 5 (A), such a fuel cell 16 has metal separators 1 (1a) arranged in parallel on both sides of a solid polymer membrane 17, and is placed above / below each separator 1 (1a). Also, a solid polymer film 17 (not shown) is arranged adjacently. That is, in the fuel cell 16, one metal separator 1 (1a) is arranged in parallel between a plurality of solid polymer membranes 17 arranged in parallel to each other and at both ends thereof. In addition, the metal separator 1 in the solid polymer film 17
The portion adjacent to has a three-layer structure of a gas diffusion electrode (not shown) disposed on both side surfaces of the solid polymer film 17 and a positive electrode catalyst electrode or a negative electrode catalyst electrode.

As shown in FIG. 5A, the solid polymer film 17
The peripheral portion 18 is a portion where the gas diffusion electrode and the catalyst layer are not formed, and is in surface contact with the sealing materials 10, 10 provided around the adjacent metal separator 1 (1a). The header portions 7a and 7b of the metal separator 1 (1a) are made of the sealing material 1
0 and the peripheral portion 18 form a sealed space. still,
The groove 6a (6c) and the groove 6b (6d) are shown in FIG. 4 (A) ((B)).
As shown in FIG. 3, the openings are arranged adjacent to each other and alternately open in opposite directions. Further, in FIG. 5A, the groove 6b (6d) of the lower metal separator 1 (1a) is located immediately below the groove 6a (6c) of the upper metal separator 1 (1a). Further, the sealing material 10 includes a header portion 7a,
Gas inlet / outlet ports 9a and 9b are provided at 7b.

Now, the operation of the fuel cell 16 using the metal separator 1 will be described. FIG. 5 (B) shows a cross section of the fuel cell 16 in which one metal separator 1 is arranged between the three solid polymer membranes 17a to 17c, and the groove 6a in the upper separator 1 is the lower separator. In No. 1, the concave groove 6b sandwiches the metal separator 17b. Fuel gas or oxidant gas is supplied to the header portions 7a and 7b of each metal separator 1 from the gas inlets 9a and 9b. In FIG. 5B, the fuel gas such as hydrogen gas or methanol, which is indicated by an arrow in the upper solid line, flows from the header portion 7a of the upper metal separator 1 to the header portion 7a on the opposite side while shunting the grooves 6a. To be done. In addition, an oxidant gas such as oxygen or air indicated by an arrow with a broken line on the lower side in FIG. 5 (B) flows from the header portion 7b of the lower metal separator 1 into each groove 6b.
Is distributed to the header portion 7b on the opposite side.

While flowing in the groove 6a or groove 6b, the fuel gas or the oxidant gas is partially adsorbed on the catalyst electrode on the negative electrode side or the positive electrode side in the solid polymer films 17a and 17c adjacent to each other. Contact. At this time, hydrogen contained in the fuel gas (shown by a solid arrow in FIG. 5 (B)) flowing in the concave groove 6a of the surface 2a of the solid polymer film 17a facing the catalyst electrode on the negative electrode side is shown. Is decomposed into hydrogen ions and electrons. Such hydrogen penetrates the solid polymer film 17a upward and moves to the catalyst electrode on the positive electrode side. Further, the electrons perform a required action while energizing an external circuit (not shown), and then are sent to the positive electrode side catalyst electrode in the solid polymer film 17a. On the other hand, in the concave groove 6b of the back surface 2b facing the catalyst electrode on the positive electrode side in the solid polymer film 17c, the oxidant gas that is the positive electrode active material (shown by the broken line arrow in FIG. 5B) is the same as above. Distribute to. At this time, while flowing in the groove 6b,
Since the oxidant gas comes into contact with the catalyst electrode on the positive electrode side in the adjacent solid polymer film 17c, oxygen reacts with hydrogen ions and electrons to generate water.

FIG. 5C shows a cross section adjacent to either of the front and rear directions of FIG. 5B, showing the metal separators 17a to 17c.
The metal separators 1 are arranged in between, and the groove 6b is formed in the upper separator 1 and the groove 6b is formed in the lower separator 1.
a sandwiches the central metal separator 17b. Figure 5
The fuel gas indicated by the arrow in the lower solid line in (C) is circulated from the header portion 7a of the lower metal separator 1 to the opposite header portion 7a while shunting the recessed grooves 6a. In addition, the oxidant gas indicated by the arrow in the upper broken line in FIG. 5C flows from the header portion 7b of the upper metal separator 1 to the header portion 7b on the opposite side while shunting the recessed grooves 6b. At this time, hydrogen contained in the fuel gas (shown by a solid arrow in FIG. 5 (C)) flowing in the concave groove 6a of the surface 2a of the solid polymer film 17b facing the catalyst electrode on the negative electrode side becomes hydrogen ion. Decomposed into electrons, the hydrogen penetrates the solid polymer film 17b upward and moves to the catalyst electrode on the positive electrode side. Also,
The electrons are sent to a positive electrode-side catalyst electrode in the solid polymer film 17b after energizing an external circuit (not shown).

On the other hand, in the concave groove 6b of the back surface 2b facing the catalyst electrode on the positive electrode side in the solid polymer film 17b, the oxidizing gas is used.
(Indicated by a dashed arrow in FIG. 5 (C)) circulates as above,
While passing through the groove 6b, the adjacent solid polymer film 17
Since it contacts with the catalyst electrode on the positive electrode side in b, oxygen reacts with hydrogen ions and electrons to produce water. According to the fuel cell 16 as described above, the plurality of solid polymer films 17a to 17a
By arranging one metal separator 1 (1a) in parallel between c and both ends (upper and lower ends) thereof, the entire size can be made compact and lightweight, and chemical energy can be efficiently generated by electricity. It can be converted into energy. Moreover, the electric resistance of the current flowing through the metal separator 1 (1a) can be reduced. Therefore, the fuel cell 16 is extremely effective as a power source for vehicles, for example. 5 (B) and 5 (C), the fuel gas and the oxidant gas flow in opposite directions, but they may flow in the same direction.

FIG. 6A is an external perspective view of a metal separator 20 having a different form. The metal separator 20 is also made of the same thin metal plate having a front surface 21 and a back surface 22, and as shown in FIG. 6 (A), a plurality of ridges 24a parallel to each other are provided at the center of the front surface 21. Article 24
It has a concave-convex portion 23a composed of a plurality of concave grooves 26a which are alternately positioned between a. Further, a pair of header portions 27 orthogonal to these are provided at both ends in the longitudinal direction of the plurality of convex stripes 24a and the concave grooves 26a. Each of the ridges 24a and each of the grooves 26a has a trapezoidal cross section, but as shown in FIG. 3 and FIG. 4 (B), the cross section may have a U-shape (quadrangle).

As shown in FIGS. 6A and 6B, the step portion 2 is formed around the uneven portion 23a of the surface 21 and the header portion 27.
It is surrounded by 5, 25 and has a flat peripheral portion 28 on its outer periphery.
Is besieged. As shown in FIG. 6B, each header 27 has a trapezoidal shape with a modified cross section. In addition, the peripheral portion 2
8 is located at the same level as the top surface of each ridge 24a, and has the same gas inlet 9a, outlet 9b, and bolt through hole 13 as described above.
Etc. are formed. Further, as shown in the sectional view of FIG. 6 (B), each of the ridges 2 is formed on the back surface 22 of the metal separator 20.
A concave-convex portion 23b is formed in the central portion, which includes a plurality of concave grooves 26b adjacent to the back surface side of 4a and a plurality of convex stripes 24b adjacent to the rear surface side of each concave groove 26a and located between the concave grooves 26b. Has been done. The ridges 24a and the grooves 26a may be ridges or grooves whose ends are rounded similarly to the above, and the widths of the grooves 26a and 26b may be different from each other.

Further, at both ends in the longitudinal direction of the convex strip 24b and the concave groove 26b in the concave-convex portion 23b, there are positioned header portions 29 whose cross section is substantially V-shaped orthogonal to them. As shown in FIG. 6B, the header portions 27 and 29 of the front and back surfaces 21 and 22 are provided at a position lower than the height of the ridges 24a and 24b and shallower than the depth of the concave grooves 26a and 26b. There is. That is, the header portions 27 and 29 are the ridges 2
Almost half the height of 4a, 24b and the recessed grooves 26a, 26
It is located at a level approximately half the depth of b, and has a step 2
It is connected via 5 and 25 to the peripheral portion 28 which is biased to the same level as the top surface of each ridge 24a on the surface 21. The header portions 27 and 29 may be formed such that the vicinity of the outlet / inlet of fuel gas or the like is deepened and the opposite side is shallowed.

FIG. 6C is a sectional view showing a unit portion of the fuel cell 30 using the metal separator 20. As shown in FIG. 6 (C), such a fuel cell 16 is one in which one metal separator 20 is arranged in parallel between a plurality of solid polymer membranes 32, 32 arranged in parallel to each other and both ends thereof. The solid polymer film 32 (not shown) is also arranged on the upper surface of the upper separator 20 in the drawing. As shown in FIG. 6C, a peripheral portion 34 similar to the above is located around the solid polymer film 32, and a rectangular frame-shaped sealing material (gasket) 36 is arranged above and below the peripheral portion 34. Such sealing material 36
Also, the peripheral part 28 of the metal separator 20 is sandwiched between the adjacent peripheral part 34 of the solid polymer film 32, which is made of an elastic body such as synthetic rubber. Such sealing material 3
The header portions 27 and 29 of each metal separator 20 become a sealed space by 6 and the peripheral portion 34.

In FIG. 6C, for the sake of convenience, the groove 26b of the lower metal separator 20 is located immediately below the groove 26a of the upper metal separator 20. And FIG.
As shown in (C), the fuel gas indicated by solid and broken arrows flows from one header portion 27, 29 of the upper and lower metal separators 20 into the groove 26a and flows into the other header portion 27, 29. To do. In addition, the oxidant gas shown by the upper and lower single-dot chain arrows flows from the one header portion 29, 27 of each of the upper and lower metal separators 20 into the recessed groove 26b and flows into the other header portion 29, 27.

Recessed groove 26a in each metal separator 20
While flowing in the fuel gas, a part of the fuel gas comes into contact with the catalyst electrode on the negative electrode side in the adjacent solid polymer membrane 32, and the hydrogen contained in the fuel gas is decomposed into hydrogen ions and electrons. To be done. Further, while flowing in the concave groove 26b of each separator 20, a part of the oxidant gas is adjacent to the solid polymer film 3
In contact with the catalyst electrode on the positive electrode side in 2, oxygen, hydrogen ions, and electrons react to generate water. According to the fuel cell 30 using the metal separator 20 as described above, the chemical energy of the gas can be efficiently converted into electric energy and the whole can be made compact, and the sealing material 36 allows a plurality of solid polymer membranes to be formed. 32 and a plurality of metal separators 2
0 and 0 can be easily laminated and fixed with airtightness. Moreover, the electric resistance of the current flowing through the metal separator 20 is also reduced.

Next, FIG. 7 shows the second metal separator 40 and the fuel cell 60 using the same according to the present invention.
~ It demonstrates by FIG. 7A and 7B are plan views of the front surface 40a and the back surface 40b of the second metal separator 40. The metal separator 40 is molded from a metal thin plate made of the same material as described above, and has a substantially square shape (rectangle) in a plan view as illustrated. In addition, such a metal thin plate is also used for the metal base material 14 and the metal base material 14
And the thin film layer 15 made of a noble metal such as Au coated on the front surface and the back surface.

The surface 40a of the metal separator 40 is shown in FIG.
As shown in (A), (a1), and (a2), a plurality of recessed grooves 43, 45 whose front surface 40a is a concave portion and whose rear surface 40b is a convex portion
And a plurality of ridges 42 and 44 which are alternately arranged and whose front surface 40a is a convex portion and rear surface 40b is a concave portion. As illustrated by the slope 45a of the groove 45 at the left end in the width direction in FIG. 7A, the groove 43 and the ridges 42 are
The sections are trapezoidal and are arranged parallel to each other. Figure 7
As shown in (A), between one end of the concave grooves 43, 45 of the surface 40a and one end 42a, 44a of the ridges 42, 44 and one side (upper side) or the other side (lower side) of the metal thin plate, A plurality of bypass flow paths 46 and 47 are alternately provided in opposite directions. The bypass passages 46 and 47 are provided at a position lower than the height of the convex strip 42 and the like and shallower than the depth of the concave groove 43 and the like.

The back surface 40b of the metal separator 40 is shown in FIG.
As shown in (B), (b1), and (b2), a plurality of ridges 53, 55 whose back surface 40b is a convex portion and front surface 40a is a concave portion
And a plurality of concave grooves 52 and 54 which are located alternately with each other and whose rear surface 40b is a concave portion and whose front surface 40a is a convex portion. As illustrated by the slope 52a of the groove 52 at the left end in the width direction in FIG. 7B, the ridges 53 and the groove 52 are trapezoidal in cross section and arranged in parallel with each other. As shown in FIG. 7B, on the back surface 40b, between one end of the concave grooves 52, 54 and one end 53b, 55b of the ridges 53, 55 and one side (upper side) or the other side (lower side) of the thin metal plate. The plurality of bypass flow paths 56, 57 are alternately provided in opposite directions. The bypass flow paths 56, 57 are provided at a position lower than the height of the ridge 53 and the depth of the recess 52. ing. 7 (A) and 7 (B), the ridges 42 and the like are shown by thick lines and the recessed grooves 43 and the like are shown by thin lines for convenience.

Further, as shown in FIGS. 7 (a1) and (b1),
The ridges 53 and 55 of the back surface 40b are located on the back surface 40b side of the concave grooves 43 and 45 of the front surface 40a, and the front surface 40a
On the side of the back surface 40b of the ridges 42 and 44, the concave grooves 54 and 52 of the back surface 40b are located in a back-to-back relationship with each other. Further, as shown in FIGS. 7 (A), (a2) and FIG.
The other ends of the concave grooves 43, 45 and the other ends of the ridges 42, 44 in are the other side (upper side) or one side (lower side) of the thin metal plate.
Has reached. As shown in FIGS. 7 (B), (b2), and FIG. 8, the other end of the concave grooves 52, 54 and the other end of the ridges 53, 55 on the back surface 40b are also the other side (upper side) or one side (upper side) of the thin metal plate. (Bottom edge). The ridges 42 and the grooves 43 may be ridges or grooves with rounded ends as described above, and the grooves 43 on the front surface 40a and the grooves 52 on the back surface 40b may be formed.
The width may be different. The metal separator 40 described above is formed by, for example, pressing or drawing a thin stainless steel plate, or a combination thereof.

In the metal separator 40 as described above, as indicated by the one-dot chain line arrow in FIGS.
On the surface 40a, the fuel gas supplied from the inlet at the lower left corner (not shown) is fed into the grooves 45, 43, 45, 43, 45.
Through the bypass flow paths 47, 46, 47, 46,
It is fed in a zigzag shape toward the exit at a diagonal position. Further, on the back surface 40b, as shown by broken line arrows in FIGS. 7B and 8, the oxidant gas supplied from the inlet in the upper right corner (not shown) is recessed into the grooves 52, 54, 52, 54, 52. Are circulated through the bypass flow paths 56, 57, 56, 57 and are fed in a zigzag shape toward the outlet at the lower left corner.

Further, as shown in FIG. 8, the bypass passages 46, 47, 56, 57 and the surface 4 in the metal separator 40 are arranged.
0a and the back surface 40b at both ends of the groove 45 and the ridge 5.
A sealing material (gasket) 61 is arranged along the outer side of 5 or the like so as to surround them. Such sealing material 6
1 is made of elastic synthetic rubber or the like, and has a rectangular frame-shaped main body 62 in plan view, and slits 65 and 66 that are open inward along the longitudinal direction of the inner peripheral surface 63 thereof. Figure 8
As shown in FIG. 5, the pair of sides of the metal separator 40 is inserted into the linear slit 65, and the concave and convex slits 66 are formed.
Ends such as the ridges 42 and 55 and the concave grooves 43 and 52 are inserted in the.

The sealing material 61 may be formed by joining two L-shaped or U-shaped divided pieces in a plan view. Further, the flow paths 69 for the respective gases penetrate near the corners of the sealing material 61, and the inner peripheral surface 63 near the corners,
Gas inlets or outlets 67, 68 are open. Then, as shown in FIGS. 9A and 9B, the metal separator 4
The sealing material 61 with 0 set inside is used as the solid polymer film 1
The fuel cell 60 using the metal separator 40 by being arranged between 7a to 17c and the peripheral portion 18 thereof.
Is obtained. In addition, as shown in 9 (A) and (B), the plurality of metal separators 40 are opposite to each other in the thickness direction,
Moreover, they are arranged so as to be alternately opposite.

In the fuel cell 60, the fuel gas is the front surface 40a or the back surface 40b of the metal separator 40.
While flowing through each of the zigzag-shaped long flow paths in FIG.
7c contacts the catalyst electrode on the negative electrode side, and hydrogen contained in the fuel gas is decomposed into hydrogen ions and electrons. Further, while the oxidant gas flows through the groove 43 of each separator 40 and the like, a part of the oxidant gas comes into contact with the catalyst electrode on the positive electrode side in the adjacent solid polymer films 17a to 17c, and oxygen And hydrogen ions and electrons react to produce water. According to the fuel cell 60 using the metal separator 40 as described above, the chemical energy of the gas can be efficiently converted into electric energy and the whole can be made compact, and a plurality of solid polymer can be provided by the sealing material 61 and the like. The film 17a and the like and the plurality of metal separators 40 can be easily laminated and fixed with airtightness. Moreover, the electric resistance of the current flowing through the metal separator 40 is also reduced.

The present invention is not limited to the embodiments described above. For example, the ridges 4a, 4b
Alternatively, both end surfaces in the longitudinal direction of the concave grooves 6a and 6b may be vertical surfaces along the thickness direction of the metal separator 1. Further, the ridges 24a, 24b, 42 and the like and the concave grooves 26a, 26b, 43 and the like may have a substantially quadrangular or substantially U-shaped cross section. Furthermore, the metal separator 1,
The thin metal plates 1a, 20 and 40 may be a single metal plate having excellent corrosion resistance. Further, the method of forming the concave-convex portions 3a and 3b of the metal separators 1 and 1a and the concave groove 43 of the metal separator 40 can also be performed by drawing or cold forging.

[0047]

According to the first metal separator of the present invention described above (claim 1), the plurality of concave grooves in the concavo-convex portion formed on the front surface and the back surface of a single metal thin plate are each a fuel gas. Alternatively, it serves as a flow path for the oxidant gas, and the front surface and the back surface can be utilized as either the positive electrode side substrate or the negative electrode side substrate. For this reason, 2
By forming a single metal thin plate by a press or the like without using the positive and negative electrode side substrates, it can be utilized as a metal separator having a low electric resistance. Further, according to the metal separator of claim 2, the sealing material is used to form the header portions located at both ends of each uneven portion on the front surface and the back surface of the thin metal plate as a closed space, and the fuel gas is formed between the header portion and the adjacent solid polymer membrane. It is possible to carry out a reaction such as hydrogen ionization or electronization while flowing in the concave groove of each concavo-convex portion without leaking the oxidizer gas or the oxidant gas.

On the other hand, according to the second metal separator of the present invention (Claim 3), the zigzag-shaped flow passages are surely formed on the front surface and the back surface of one metal thin plate. Can be utilized as either the positive electrode side substrate or the negative electrode side substrate that serves as a flow path for the fuel gas or the oxidant gas. Therefore, it is possible to obtain a metal separator which is made of one metal thin plate and which easily causes the reaction such as hydrogen ionization and has a small electric resistance. Also,
According to the metal separator of the fourth aspect, it is possible to reliably shield the zigzag-shaped gas flow passage that surrounds the plurality of bypass passages and the concave grooves or ridges at both ends from the outside.

Further, according to the metal separators of claims 5 and 6, the front surface and the back surface are covered with a thin film layer of a noble metal having excellent corrosion resistance, and a metal base having excellent moldability and a required strength is provided therebetween. The metal separator is made of a thin metal plate on which the material is located. Therefore, it becomes possible to obtain a metal separator which is excellent in corrosion resistance and durability and which is low cost or optimum cost. In addition, according to the fuel cell of the present invention (Claim 7), since the metal separator is a single metal thin plate, the overall thickness can be made thin and compact, and a low cost and stable operation can be obtained. The fuel cell can be used as a fuel cell.

[Brief description of drawings]

1A and 1B are plan views showing a front surface or a back surface of a first metal separator of the present invention, and FIGS. 1A and 1B are (A) and (B).
The end view which followed the aa line in the inside, or the bb line, (alpha) is a partial schematic diagram which shows the deformation | transformation form of a convex line and a concave groove.

2A and 2B are perspective views showing a front surface or a back surface of the metal separator of FIG.

3A and 3B are perspective views showing a front surface or a back surface of a metal separator having a different form.

4A is a partial cross-sectional view of the metal separator of FIGS. 1 and 2, and FIG. 4B is a partial cross-sectional view of the metal separator of FIG.

5 (A) is a schematic diagram showing a fuel cell using the metal separator of FIG. 1 (FIG. 3), and FIGS. 5 (B) and (C) are schematic diagrams showing the operation of the fuel cell.

6A is a perspective view showing the surface of a metal separator having a different configuration, FIG. 6B is a cross-sectional view as viewed along the line BB in FIG. 6A, and FIG. Schematic which shows the used fuel cell.

7 (A) and (B) are plan views showing the front surface or the back surface of a second metal separator of the present invention, (a1), (a2), (b).
1) and (b2) are lines a1-a1 and (a2-a) in (A) and (B).
The end view which followed the 2 line, the b1-b1 line, or the b2-b2 line.

8 is a perspective view showing the metal separator of FIG. 7 and a sealing material used for the same.

9 (A) and 9 (B) are cross-sectional views showing a fuel cell using the metal separator of FIGS.

10A is a schematic view showing a conventional fuel cell, FIG. 10B is a partial perspective view showing a metal separator used in such a fuel cell, and FIG. 10C is a perspective view showing a metal thin plate forming the metal separator. .

[Explanation of symbols]

1,1a, 20,40 ………………………………………………
Metal separators 2a, 21, 40a ………………………………………………
Surface 2b, 22, 40b ……………………………………………………
Back surface 3a, 3b, 3c, 3d, 23a, 23b ………………
Uneven portion 4a, 4b, 24a, 24b, 42, 44, 53, 55 ...
Ridges 6a, 6b, 26a, 26b, 43, 45, 52, 54 ...
Grooves 7a, 7b, 27, 29 ………………………………………………
Header section 10, 34, 61 ……………………………………………………
Seal material 14 ……………………………………………………………………
Metal base material 15 ……………………………………………………………………
Thin film layer 16, 30, 60 ……………………………………………………
Fuel cell 17, 32 …………………………………………………………
Solid polymer film 46, 47, 56, 57 …………………………………………
Detour flow path

Claims (7)

[Claims] 1. A groove and a ridge having a substantially rectangular shape in plan view and made of a thin metal plate having a front surface and a back surface, and having a substantially quadrangular or trapezoidal cross section with a concave or convex surface and a convex or concave back surface. A plurality of concavo-convex portions that are alternately formed in parallel with each other, at both longitudinal ends of the plurality of concavo-convex grooves of the concavo-convex portion, are orthogonal to the concave grooves and the convex stripes, and are shallower than the depth of the concave grooves and the convex stripes. And a pair of header portions provided to be lower than the height of the metal separator. 2. A sealing material having a thickness substantially the same as the depth of the groove and the height of the ridge along the outer sides of a pair of header portions provided at both ends in the longitudinal direction of the plurality of grooves of the uneven portion. It arrange | positions, The metal separator of Claim 1 characterized by the above-mentioned. 3. A metal thin plate having a substantially rectangular shape in plan view and having a front surface and a back surface, the surface having a concave portion or a convex portion and the back surface having a convex portion or a concave portion having a substantially quadrangular or trapezoidal shape and alternately formed in parallel. A plurality of concave grooves and a plurality of convex stripes formed between the one end of the concave groove and the convex stripe and one side or the other side of the thin metal plate, and the height of the convex stripe is shallower than the depth of the concave groove. A plurality of bypass passages provided at a lower level than the above, the other ends of the concave groove and the convex strip reach one side or the other side of the metal thin plate, and the plurality of bypass passages are flat. A metal separator characterized in that the metal separators are arranged in opposite directions visually. 4. The depth of the concave groove and the height of the convex line are substantially equal to the depth of the concave groove and the height of the convex line so as to surround the thin metal body along the outer sides of the plurality of bypass passages and the concave groove or the convex line. The metal separator according to claim 3, wherein the sealing material is arranged. 5. The thin metal plate comprises a metal base material and a thin film layer made of a noble metal coated on the front surface and the back surface of the metal base material, according to any one of claims 1 to 4. The metal separator according to the item. 6. The metal base material is Fe, Ni, Ti,
The thin film layer of the noble metal is made of Au, Ag, or Cu, Al, or an alloy based on any of these.
The metal separator according to claim 5, comprising Pt or Pd alone, an alloy based on any of these, or an alloy composed of two or more kinds of the above-mentioned noble metals. 7. The metal separator according to claim 1 is arranged in parallel between a plurality of solid polymer membranes arranged in parallel with each other and between both ends thereof. , A fuel cell characterized by the above.