Manufacturing method of fuel cell separator

Abstract

To provide a method for manufacturing a fuel cell separator, capable of increasing the number of separator base materials that can be deposited in one process, when a conductive film is deposited by means of a physical vapor growth method.SOLUTION: A method for manufacturing a fuel cell separator 9 includes an arrangement step in which first separator base materials 10A and second separator base materials 10B are disposed such that, as viewed from one side Q1 in an orthogonal direction with regard to a first virtual plane P1, a part of a surface 10Bd of each of the second separator base materials 10B on a cooling water surface side is exposed between the first separator base materials 10A, and as viewed from the other side Q2 in the orthogonal direction, a part of a surface 10Ad of each of the first separator base materials 10A on a cooling water surface side is exposed between the second separator base materials 10B. A conductive film 11 is deposited on both surfaces of each of the first separator base materials 10A and each of the second separator base materials 10B by a pair of vapor deposition sources 8 disposed in a deposition device 1 so as to sandwich the first virtual plane P1 and a second virtual plane P2.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a method for manufacturing a separator for a fuel cell. [Background technology]

[0002] For example, Patent Document 1 proposes a method for manufacturing a fuel cell separator. In this method, a fuel cell separator is manufactured by forming a conductive film on a separator substrate by physical vapor deposition. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2010-86897 Summary of the Invention [Problem to be solved by the invention]

[0004] Incidentally, when attempting to simultaneously form conductive films on both sides of multiple separator substrates by the physical vapor deposition method described in Patent Document 1, it is conceivable to adopt the following method, for example. Specifically, multiple separator substrates are arranged on the same plane, and conductive films are formed on both sides of the separator substrates using a pair of evaporation sources arranged on either side of this plane. However, even when films are formed in this manner, the physical vapor deposition method limits the number of separator substrates that can be processed at one time.

[0005] The present invention has been made in consideration of these problems, and its purpose is to provide a method for manufacturing a fuel cell separator that can increase the number of separator substrates that can be formed per run when forming a conductive film by physical vapor deposition. [Means for solving the problem]

[0006] In view of the problems, the present invention provides a method for manufacturing a fuel cell separator, which comprises forming conductive films by physical vapor deposition on both sides of a plurality of separator substrates placed in a film-forming apparatus, and the method for manufacturing the separator comprises arranging a plurality of first separator substrates among the plurality of separator substrates in the film-forming apparatus at regular intervals on a first imaginary plane, and arranging a plurality of second separator substrates among the plurality of separator substrates in the film-forming apparatus at regular intervals on a second imaginary plane that is spaced a regular distance from the first imaginary plane. In the arrangement step, the first separator substrate and the second separator substrate are arranged so that a portion of the surface of the second separator substrate is exposed between the first separator substrates when viewed from one side in a direction perpendicular to the first imaginary plane, and so that a portion of the surface of the first separator substrate is exposed between the second separator substrates when viewed from the other side in the perpendicular direction, and conductive films are formed on both surfaces of the first separator substrate and the second separator substrate by a pair of evaporation sources arranged in a film formation device so as to sandwich the first imaginary plane and the second imaginary plane. [Effects of the Invention]

[0007] According to the present invention, when forming a conductive film by physical vapor deposition, the number of separator substrates that can be formed per one run can be increased. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a diagram showing a film forming apparatus according to an embodiment of the present invention. [Figure 2] 1A is a schematic diagram illustrating the arrangement of the first separator substrate and the second separator substrate in the film forming processing unit in a cross section taken along line AA in FIG. 1; FIG. 1B is a diagram illustrating the arrangement of the first separator substrate and the second separator substrate as viewed from one side in a direction perpendicular to a first imaginary plane; and FIG. 1C is a diagram illustrating the arrangement of the second separator substrate and the first separator substrate as viewed from the other side in a direction perpendicular to the first imaginary plane. [Figure 3]1A is a cross-sectional view of a fuel cell separator along its short side, FIG. 1B is a graph showing the film thickness along the short side of a separator manufactured by the manufacturing method according to the present embodiment, and FIG. 1C is a graph showing the film thickness along the short side of a separator manufactured by a conventional manufacturing method. DETAILED DESCRIPTION OF THE INVENTION

[0009] A method for producing a fuel cell separator 9 according to the present invention will be described below with reference to the drawings.

[0010] 1. About fuel cell separators 9 Although not shown, a fuel cell separator (hereinafter referred to as "separator") 9 according to this embodiment is a component that separates membrane electrode gas diffusion layer assemblies (MEGA) in which gas diffusion layers are laminated on both sides of a membrane electrode assembly. A single fuel cell (not shown) is formed by sandwiching a membrane electrode gas diffusion layer assembly (MEGA) between a pair of separators 9. One side of the separator 9 abuts the MEGA. One side of the separator 9 is a gas surface on which gas flow paths for fuel gas or oxidant gas are formed. The other side of the separator 9 abuts the separator of an adjacent fuel cell when the cells are stacked. The other side of the separator 9 is a cooling water surface on which cooling water flow paths are formed.

[0011] The separator 9 has a separator substrate 10 and conductive films 11 (11C, 11D) such as carbon films formed on both sides of the separator substrate 10. One of the conductive films 11, conductive film 11C, has a uniform thickness. Therefore, conductive film 11C can be used on the gas side, which has a direct effect on power generation performance. On the other hand, the other conductive film 11D, conductive film 11, has a thinner thickness than conductive film 11C and is not uniform. Conductive film 11D can be used on the cooling water side, which has less effect on power generation performance. In this way, the conductive films 11 (11C, 11D) formed on both sides of the separator substrate 10 do not need to have the same thickness. Based on this idea, the inventors have discovered the following manufacturing method.

[0012] 2. Manufacturing method of fuel cell separator 9 The following arrangement process is performed on a plurality of separator substrates 10. Thereafter, the separator substrates 10 undergo a series of processes from a surface treatment process to a vacuum treatment process using a film-forming apparatus 1 shown in Figure 1. The separator substrates 10 undergo these processes to produce a separator 9.

[0013] 2-1. Placement process In the arrangement step, the plurality of separator substrates 10, 10, ... are arranged on each of the two frames 5, 5. First, the configuration of the apparatus, such as the frame 5 on which the plurality of separator substrates 10 are arranged, will be described.

[0014] Each frame 5 has a gate-like shape and is fixed to a movable table 6. The movable table 6 moves together with the frame 5 within the film forming apparatus 1 from the surface treatment section 2 to the vacuum treatment section 4, which will be described later. In this embodiment, the two frames 5 are arranged facing each other in a direction perpendicular to the direction of movement of the movable table 6. The frames 5 are provided with mounting sections 12, which mount the separator substrate 10, spaced apart in the vertical direction so as to connect both ends of the frame 5. A first imaginary plane P1 is formed inside one of the two frames 5, and a second imaginary plane P2 is formed inside the other frame 5. The first imaginary plane P1 and the second imaginary plane P2 are separated by a constant distance P.

[0015] The multiple separator substrates 10 are composed of multiple first separator substrates 10A and multiple second separator substrates 10B. Each first separator substrate 10A has a gas surface side surface 10Ac and a cooling water surface side surface 10Ad. Each second separator substrate 10B has a gas surface side surface 10Bc and a cooling water surface side surface 10Bd. The multiple first separator substrates 10A are arranged at regular intervals D on a first imaginary plane P1. The multiple second separator substrates 10B are arranged at regular intervals D on a second imaginary plane P2. In this embodiment, the intervals D between the multiple first separator substrates 10A arranged on the first imaginary plane P1 are approximately the same as the intervals D between the multiple second separator substrates 10B arranged on the second imaginary plane P2. A plurality of mask jigs for holding a plurality of first and second separator substrates 10A, 10B may be arranged within the first and second imaginary planes P1, P2. The mask jigs hold both edges of the plurality of first and second separator substrates 10A, 10B. For ease of explanation, in FIGS. 2(b) and 2(c), the group of first separator substrates 10A and the group of second separator substrates 10B are shown generally offset in the vertical direction. In this embodiment, the group of first separator substrates 10A and the group of second separator substrates 10B are generally aligned in the vertical direction.

[0016] As shown in FIG. 2(b), the first separator substrate 10A and the second separator substrate 10B are viewed from one side Q1 in a direction perpendicular to the first imaginary plane P1. The first separator substrate 10A and the second separator substrate 10B are arranged between the first separator substrates 10A so that the exposed surface 10Bd of the second separator substrate 10B facing the cooling water surface, other than at least one edge, is visible. Similarly, as shown in FIG. 2(c), the first separator substrate 10A and the second separator substrate 10B are viewed from the other side Q2 in a direction perpendicular to the first imaginary plane P1. The first separator substrate 10A and the second separator substrate 10B are arranged between the second separator substrates 10B so that the exposed surface 10Ad of the first separator substrate 10A facing the cooling water surface, other than at least one edge, is visible. Alternatively, the second separator substrate 10B when viewed from one side Q1 and the first separator substrate 10A when viewed from the other side Q2 may be arranged so that at least one edge is exposed, and the central portion is exposed. The first and second separator substrates 10A, 10B are arranged on the frames 5 in the arrangement step and then moved together with the moving stage 6 from the surface treatment section 2 to the vacuum treatment section 4.

[0017] 2-2. Surface treatment process First, in this embodiment, the surface treatment step is performed on the surfaces 10Ac, 10Ad, 10Bc, and 10Bd of the first and second separator substrates 10A and 10B in the surface treatment section 2. The surface treatment is, for example, roughening of the surfaces 10Ac, 10Ad, 10Bc, and 10Bd of the first and second separator substrates 10A and 10B, such as etching. As shown in FIG. 1 , a pair of plasma ion sources 7 is used for the surface treatment. After the surface treatment section 2 is evacuated, the pair of plasma ion sources 7 irradiate plasma onto the surfaces 10Ac, 10Ad, 10Bc, and 10Bd of the first and second separator substrates 10A and 10B from positions sandwiching the first and second separator substrates 10A and 10B. This provides an anchor effect to the conductive film 11 (11C, 11D) formed in the next process by the film forming processing unit 3, thereby improving the adhesion of the conductive film 11 (11C, 11D) to the first and second separator substrates 10A, 10B.

[0018] 2-3. Film formation process The film formation process is performed by physical vapor deposition in the film formation processing unit 3. The roughened first and second separator substrates 10A and 10B pass through the surface processing unit 2 and then move to the film formation processing unit 3 along with the moving stage 6. The film formation process is performed using a pair of evaporation sources 8, 8 arranged on opposing inner wall surfaces of the film formation processing unit 3 along the direction of movement of the moving stage 6. The material of the evaporation source 8 is a carbon material or a titanium material, and preferably has higher corrosion resistance and higher conductivity than the material of the first and second separator substrates 10A and 10B. After the film formation processing unit 3 is evacuated, the first and second separator substrates 10A and 10B are formed by physical vapor deposition from the pair of evaporation sources 8. The material of the evaporation source 8 is emitted in a relatively linear manner.

[0019] According to this embodiment, the first and second separator substrates 10A and 10B are arranged such that a portion of the cooling water surface-side surface 10Bd of the second separator substrate 10B is exposed between the first separator substrates 10A when viewed from one side Q1 perpendicular to the first imaginary plane P1. A conductive film 11C is formed on the gas surface-side surface 10Ac of the first separator substrate 10A, which faces the one side Q1, by the vapor deposition source 8 on the one side Q1. At the same time, material from the vapor deposition source 8 on the one side Q1 passes between the first separator substrates 10A and forms a conductive film 11D on the cooling water surface-side surface 10Bd of the second separator substrate 10B. Some of the material from the vapor deposition source 8 on the one side Q1 flows around the first imaginary plane P1 and contributes to the formation of the conductive film 11D on the cooling water surface-side surface 10Bd of the second separator substrate 10B.

[0020] Similarly, the first and second separator substrates 10A and 10B are arranged so that a portion of the cooling water surface-side surface 10Ad of the first separator substrate 10A is exposed between the second separator substrates 10B when viewed from the other side Q2 in the perpendicular direction. A conductive film 11C is formed on the gas surface-side surface 10Bc of the second separator substrate 10B, which faces the other side Q2, by the vapor deposition source 8 on the other side Q2. At the same time, material from the vapor deposition source 8 on the other side Q2 passes between the second separator substrates 10B and forms a conductive film 11D on the cooling water surface-side surface 10Ad of the first separator substrate 10A. Some of the material from the vapor deposition source 8 on the other side Q2 flows around the second imaginary plane P2 and contributes to the formation of the conductive film 11D on the cooling water surface-side surface 10Ad of the first separator substrate 10A.

[0021] In this way, conductive films 11 (11C, 11D) can be formed on both surfaces of a plurality of first and second separator substrates 10A, 10B arranged on first and second imaginary planes P1, P2, respectively, across the pair of vapor deposition sources 8. As a result, when forming conductive films 11 (11C, 11D) by physical vapor deposition, the number of first and second separator substrates 10A, 10B that can be formed in one run can be increased.

[0022] In this way, as shown in FIGS. 3(a) and 3(b), a uniform conductive film 11C is formed on the entire gas-side surface 10Ac of the first separator substrate 10A, which faces one side Q1 perpendicular to the first imaginary plane P1. A conductive film 11D, which is thinner and less uniform than the conductive film 11C, is formed on the cooling-water-side surface 10Ad of the first separator substrate 10A, which faces the other side Q2 perpendicular to the first imaginary plane P1. However, as shown in FIGS. 3(a) and 3(b), the thickness of the conductive film 11D is approximately uniform in the center and gradually decreases toward both ends. The same applies to the conductive films 11C and 11D formed on the second separator substrate 10B. The conductive films 11D formed on the first and second separator substrates 10A and 10B are used on the cooling-water-side surface, and therefore have little effect on the power generation characteristics of the fuel cell.

[0023] 2-4. Vacuum processing The first and second separator substrates 10A, 10B (separator 9) that have been subjected to the film formation process pass through the film formation process section 3, and then move together with the moving stage 6 to the vacuum process section 4. Particles and the like other than the conductive films 11 (11C, 11D) adhering to the first and second separator substrates 10A, 10B that have moved into the vacuum process section 4 are removed when a vacuum is created in the vacuum process section 4. [Explanation of symbols]

[0024] 1: film forming apparatus, 2: surface treatment section, 3: film forming treatment section, 4: vacuum treatment section, 5: frame, 6: moving stage, 7: plasma ion source, 8: deposition source, 9: fuel cell separator, 10: separator substrate, 10A: first separator substrate, 10B: second separator substrate, 11: conductive film, 12: attachment section

Claims

[Claim 1] A method for manufacturing a fuel cell separator, in which conductive films are formed by physical vapor deposition on both sides of a plurality of separator substrates placed in a film-forming apparatus, comprising: The method for producing the separator includes: Among the plurality of separator substrates, a plurality of first separator substrates are arranged in the film forming apparatus at regular intervals on a first imaginary plane; a disposing step of disposing a plurality of second separator substrates, among the plurality of separator substrates, at regular intervals on a second imaginary plane that is spaced a regular distance from the first imaginary plane, in the film forming apparatus; in the arranging step, the first separator substrate and the second separator substrate are arranged so that, when viewed from one side in a direction perpendicular to the first imaginary plane, a portion of a surface of the second separator substrate is exposed between the first separator substrates, and when viewed from the other side in the perpendicular direction, a portion of a surface of the first separator substrate is exposed between the second separator substrates, a conductive film formed on both surfaces of the first separator substrate and the second separator substrate by a pair of vapor deposition sources arranged in the film forming apparatus so as to sandwich the first imaginary plane and the second imaginary plane therebetween.

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