Manufacturing method of separator for fuel cells

Abstract

To provide a manufacturing method of a separator for fuel cells capable of increasing the number of separator substrates which can be deposited per time when depositing conductive films according to a physical vapor growth method.SOLUTION: In a manufacturing method of a separator 9 for fuel cells, while keeping a state where each of a plurality of first separator substrates 10A and each of a plurality of second separator substrates 10B are spaced by a fixed interval D and while sliding at least one of the plurality of first separator substrates 10A and the plurality of second separator substrates 10B along a first or second virtual plane, conductive films 11 are deposited on both faces of the first separator substrate 10A and the second separator substrate 10B by a pair of vapor deposition sources 8 and 8 disposed inside of a deposition device 1 so as to hold a first virtual plane P1 and a second virtual plane P2 therebetween.SELECTED DRAWING: Figure 2

Description

[Technical field]

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

[0002] For example, Patent Document 1 proposes a method for producing a separator for a fuel cell, in which a conductive film is formed on a separator substrate by physical vapor deposition to produce a separator for a fuel cell. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2010-86897 A 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 shown in Patent Document 1, for example, it is assumed that the following method will be adopted. Specifically, multiple separator substrates are arranged on the same plane, and conductive films are formed on both sides of the separator substrates by a pair of deposition sources arranged on either side of the plane. However, even if the films are formed as described above, the number of separator substrates that can be processed at one time is limited by the physical vapor deposition method.

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

[0006] In view of the problems, a method for manufacturing a fuel cell separator according to the present invention is a method for manufacturing a fuel cell separator, which comprises forming a conductive film by physical vapor deposition on both sides of a plurality of separator substrates arranged in a film-forming apparatus, the method for manufacturing the separator comprising: arranging a plurality of first separator substrates among the plurality of separator substrates in the film-forming apparatus at fixed 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 fixed intervals on a second imaginary plane spaced a fixed distance from the first imaginary plane; and in the arranging step, when viewed from one side in a direction perpendicular to the first imaginary plane, a conductive film is formed between the first separator substrates and the second separator substrates. The first separator substrate and the second separator substrate are arranged so that a portion of the surface of the separator substrate is exposed and, when viewed from the other side in the perpendicular direction, a portion of the surface of the first separator substrate is exposed between the second separator substrates. While each of the plurality of first separator substrates and the plurality of second separator substrates is maintained at the constant interval, at least one of the plurality of first separator substrates and the plurality of second separator substrates is slid along the first or second imaginary plane, and a conductive film is formed on both sides of the first separator substrate and the second separator substrate by a pair of deposition sources arranged in a film formation apparatus so as to sandwich the first imaginary plane and the second imaginary plane. Effect 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 at one time can be increased. [Brief description of the drawings]

[0008] [Figure 1] 1 is a diagram showing a film forming apparatus according to an embodiment of the present invention; [Diagram 2]1. (a) is a schematic diagram for explaining the arrangement of the first separator substrate and the second separator substrate in a film forming processing unit in a cross section along line AA in FIG. 1, (b) is a diagram showing the arrangement relationship between the first separator substrate and the second separator substrate when viewed from one side in a direction perpendicular to a first imaginary plane in the first film forming processing unit, (c) is a diagram showing the arrangement relationship between the second separator substrate and the first separator substrate when viewed from the other side in a direction perpendicular to the first imaginary plane in the first film forming processing unit, (d) is the arrangement relationship in the second film forming processing unit corresponding to (b), and (d) is the arrangement relationship in the second film forming processing unit corresponding to (c). [Diagram 3] 1A is a cross-sectional view along the short side direction of a separator for a fuel cell, FIG. 1B is a graph showing the film thickness along the short side direction of a separator manufactured by a manufacturing method according to the present embodiment, and FIG. 1C is a graph showing the film thickness along the short side direction of a separator manufactured by a manufacturing method according to a comparative example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, a method for manufacturing a fuel cell separator 9 according to the present invention will be described with reference to the drawings. Although not shown, the fuel cell separator (hereinafter referred to as "separator") 9 according to this embodiment is a member that separates membrane electrode gas diffusion layer assemblies in which gas diffusion layers are laminated on both sides of a membrane electrode assembly. A single cell of a 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 against the MEGA. One side of the separator 9 is a gas surface in which a gas flow path for a fuel gas or an oxidant gas is formed. The other side of the separator 9 abuts against the separator of an adjacent fuel cell as the cells are stacked. The other side of the separator 9 is a cooling water surface in which a cooling water flow path is formed.

[0010] 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. The conductive film 11C on one side of the conductive film 11 has a uniform thickness. Therefore, the conductive film 11C can be used on the gas surface side, which has a direct effect on the power generation performance. On the other hand, the conductive film 11D on the other side of the conductive film 11 has a thickness smaller than that of the conductive film 11C, and the thickness is not uniform. The conductive film 11D can be used on the cooling water surface side, which is less affected by the 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. From this idea, the inventor has found the following manufacturing method.

[0011] 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 Fig. 1. The separator substrates 10 undergo these processes to produce a separator 9.

[0012] In the arrangement step, the separator substrates 10, 10, ... are arranged on two frames 5, 5, respectively. Each frame 5 has a gate-shaped shape and is fixed to a moving stage 6. The moving stage 6 moves together with the frame 5 from a surface treatment section 2 to a vacuum treatment section 4, which will be described later, in the film forming apparatus 1. In this embodiment, the two frames 5 are arranged facing each other in a direction perpendicular to the moving direction of the moving stage 6. The frame 5 is provided with mounting sections 12 for mounting the separator substrates 10 at intervals 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 spaced apart from each other by a certain distance P.

[0013] The separator substrates 10 are composed of a plurality of first separator substrates 10A and a plurality of second separator substrates 10B. Each of the first separator substrates 10A has a gas surface side surface 10Ac and a cooling water surface side surface 10Ad. Each of the second separator substrates 10B has a gas surface side surface 10Bc and a cooling water surface side surface 10Bd. The first separator substrates 10A are arranged at a constant interval D on a first imaginary plane P1. The second separator substrates 10B are arranged at a constant interval D on a second imaginary plane P2. In this embodiment, the interval D between the first separator substrates 10A arranged on the first imaginary plane P1 and the interval D between the second separator substrates 10B arranged on the second imaginary plane P2 are approximately the same. 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 plurality of mask jigs hold both edges of the plurality of first and second separator substrates 10A, 10B. For convenience of explanation, in Figs. 2(b) and (c), the group of first separator substrates 10A and the group of second separator substrates 10B are generally shown shifted in the vertical direction. In this embodiment, the group of first separator substrates 10A and the group of second separator substrates 10B generally coincide in the vertical direction.

[0014] 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 at least one edge of the exposed surface 10Bd of the second separator substrate 10B on the cooling water surface side can be seen. 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 at least one edge of the exposed surface 10Ad of the first separator substrate 10A on the cooling water surface side can be seen. 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 the central portion is exposed in addition to being arranged so that at least one edge portion is exposed. The first and second separator substrates 10A, 10B are moved from the surface treatment section 2 to the vacuum treatment section 4 together with the moving stage 6 while being arranged on each frame 5 in the arrangement step.

[0015] 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. For the surface treatment, as shown in FIG. 1, a pair of plasma ion sources 7 are used. After the surface treatment section 2 is brought into a vacuum state, 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 first and second film forming processing units 3A and 3B in the next process, thereby improving the adhesion of the conductive film 11 (11C, 11D) to the first and second separator substrates 10A and 10B.

[0016] The film formation process is performed by physical vapor deposition in the first and second film formation processing units 3A and 3B, which are 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 together with the moving stage 6 to the first film formation processing unit 3A. The film formation process is performed using a pair of deposition sources 8, 8 arranged on the inner wall surfaces of the film formation processing unit 3 that face each other along the moving direction of the moving stage 6 (see Figs. 3(b) and (c)). The material of the deposition source 8 is a carbon material or a titanium material, and is preferably a material that 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 into films by physical vapor deposition using a pair of deposition sources 8, 8. The material of the deposition source 8 is emitted relatively linearly.

[0017] Thereafter, when moving from the first film forming processing unit 3A to the second film forming processing unit 3B, the plurality of first separator substrates 10A and the plurality of second separator substrates 10B are kept in a state D with a certain distance between them, and at least one of the plurality of first separator substrates 10A and the plurality of second separator substrates 10B (in this embodiment, the plurality of first separator substrates 10A) is slid along the first imaginary plane P1 (specifically, along the moving direction of the moving stage 6) while a film is formed by the deposition sources 8, 8 (see FIGS. 3(d) and (e)). Such sliding is performed by sliding at least one of the pair of frames 5, 5 relatively using a driving source such as a motor. In addition to this, for example, the above-mentioned sliding may be performed by an interlocking mechanism interlocked with the moving stage 6.

[0018] According to this embodiment, the first and second separator substrates 10A and 10B are arranged such that a part of the surface 10Bd of the second separator substrate 10B on the cooling water surface side 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 surface 10Ac of the first separator substrate 10A on the gas surface side facing the one side Q1 by the deposition source 8 on the one side Q1 (see FIG. 3(a)). At the same time, a material from the deposition source 8 on the one side Q1 passes between the first separator substrates 10A, and a conductive film 11D is formed on the surface 10Bd of the second separator substrate 10B on the cooling water surface side. Here, as shown in Figures 2(b) to 2(d), in the film formation process, the multiple first separator substrates 10A are slid along the first imaginary plane P1 relative to the multiple second separator substrates 10B. Therefore, compared to the case of film formation without sliding (see Figure 3(c)), the material of the deposition source 8 is prevented from flowing around the first imaginary plane P1 and the material of the deposition source 8 reaches the second separator substrate 10B directly, so that a conductive film 11D with a more uniform thickness can be formed (see Figure 3(b)).

[0019] Similarly, the first and second separator substrates 10A and 10B are arranged such that a portion of the surface 10Ad of the first separator substrate 10A facing the cooling water surface is exposed between the second separator substrates 10B. A conductive film 11C is formed on the surface 10Bc of the gas surface of the second separator substrate 10B facing the other side Q2 by the deposition source 8 on the other side Q2 (see FIG. 3(a)). At the same time, material from the deposition source 8 on the other side Q2 passes between the second separator substrates 10B, and a conductive film 11D is formed on the surface 10Ad of the first separator substrate 10A facing the cooling water surface. Similarly, as shown in Figures 2(c) to 2(e), the sliding of the multiple first separator substrates 10A during the film formation process prevents the material of the deposition source 8 from flowing around the second imaginary plane P2, and the material of the deposition source 8 reaches the first separator substrate 10A directly, thereby forming a conductive film 11D with a more uniform thickness (see Figure 3(b)).

[0020] In this way, the conductive films 11 (11C, 11D) can be formed on both sides of the first and second separator substrates 10A, 10B arranged on the first and second imaginary planes P1, P2, respectively, with the pair of deposition sources 8 in between. As a result, when forming the conductive films 11 (11C, 11D) by physical vapor deposition, the number of the first and second separator substrates 10A, 10B that can be formed per one time can be increased. Note that the conductive film 11D, which is thinner than the conductive film 11C, is formed on the surface 10Ad of the first separator substrate 10A facing the other side Q2 perpendicular to the first imaginary plane P1 on the cooling water surface side. The same applies to the conductive films 11C, 11D formed on the second separator substrate 10B. However, since the conductive film 11D formed on the first and second separator substrates 10A, 10B is used on the coolant surface side, it has almost no effect on the power generation characteristics of the fuel cell.

[0021] Finally, the first and second separator substrates 10A, 10B (separator 9) that have been subjected to the film formation process pass through the film formation processing section 3, and then move together with the moving stage 6 to the vacuum processing 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 been moved into the vacuum processing section 4 are removed when a vacuum is applied in the vacuum processing section 4. [Explanation of symbols]

[0022] 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, comprising forming a conductive film on both sides of a plurality of separator substrates arranged in a film forming apparatus by a physical vapor deposition method, the method comprising the steps of: The method for producing the separator includes the steps of: Among the plurality of separator substrates, a plurality of first separator substrates are disposed 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 a fixed interval on a second imaginary plane that is spaced a fixed 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 such 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 deposition sources arranged in the film forming apparatus so as to sandwich the first imaginary plane and the second imaginary plane, while sliding at least one of the plurality of first separator substrates and the plurality of second separator substrates along the first or second imaginary plane while maintaining the constant interval between each of the plurality of first separator substrates and the plurality of second separator substrates.

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