Manufacturing method for fuel cell separators

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 manufacturing a separator for a fuel cell.

Background Art

[0002] For example, Patent Document 1 proposes a method for manufacturing a separator for a fuel cell. In this method, a conductive film is formed on a separator substrate by physical vapor deposition to manufacture a separator for a fuel cell.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, when trying to simultaneously form a conductive film on both sides of a plurality of separator substrates by the physical vapor deposition method shown in Patent Document 1, for example, the following method is assumed to be adopted. Specifically, a plurality of separator substrates are arranged on the same plane, and a pair of evaporation sources arranged so as to sandwich this plane are used to form a conductive film on both sides of the separator substrate. However, even if the film is 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 view of such problems, and an object thereof is to provide a method for manufacturing a separator for a fuel cell that can increase the number of separator substrates on which a conductive film can be formed at one time when forming the conductive film by physical vapor deposition.

Means for Solving the Problems

[0006] In view of the problems, the present invention provides 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 deposition apparatus by physical vapor deposition, wherein the method for manufacturing the separator includes a placement step of: arranging a plurality of first separator substrates from the plurality of separator substrates in a film deposition apparatus at regular intervals on a first virtual plane; and arranging a plurality of second separator substrates from the plurality of separator substrates in a film deposition apparatus at regular intervals on a second virtual plane spaced at a regular distance from the first virtual plane, wherein in the placement step, when viewed from one side in a direction perpendicular to the first virtual plane, the second separator substrates are placed between the first separator substrates. The first and second separator substrates are arranged such that a portion of the surface of the separator substrate is exposed, and when viewed from the other side in a 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 maintains the state of being spaced apart, at least one of the plurality of first separator substrates and the plurality of second separator substrates is slid along the first or second virtual plane, and a conductive film is deposited on both sides of the first and second separator substrates by a pair of deposition sources arranged in a film deposition apparatus so as to sandwich the first and second virtual planes. [Effects of the Invention]

[0007] According to the present invention, when depositing a conductive film by physical vapor deposition, the number of separator substrates that can be deposited per batch can be increased. [Brief explanation of the drawing]

[0008] [Figure 1] This figure shows a film deposition apparatus according to an embodiment of the present invention. [Figure 2](a) is a schematic diagram illustrating the arrangement of the first separator substrate and the second separator substrate within the film deposition processing unit in a cross-section along line AA in Figure 1; (b) is a diagram showing the arrangement relationship between the first separator substrate and the second separator substrate as viewed from one side perpendicular to the first virtual plane within the first film deposition processing unit; (c) is a diagram showing the arrangement relationship between the second separator substrate and the first separator substrate as viewed from the other side perpendicular to the first virtual plane within the first film deposition processing unit; (d) is the arrangement relationship of the second film deposition processing unit corresponding to (b); and (d) is the arrangement relationship within the second film deposition processing unit corresponding to (c). [Figure 3] (a) is a cross-sectional view of a fuel cell separator along the short side direction, (b) is a graph showing the film thickness along the short side direction of a separator manufactured by the manufacturing method according to this embodiment, and (c) is a graph showing the film thickness along the short side direction of a separator manufactured by the manufacturing method according to a comparative example. [Modes for carrying out the invention]

[0009] The method for manufacturing the fuel cell separator 9 according to the present invention will be described below with reference to the drawings. Although not shown in the drawings, the fuel cell separator 9 according to this embodiment (hereinafter referred to as "separator") is a member that partitions membrane electrode gas diffusion layer assemblies, in which gas diffusion layers are laminated on both sides of the membrane electrode assemblies. A single cell of a fuel cell (not shown) is formed by sandwiching a membrane electrode gas diffusion layer assemblies (MEGA) between a pair of separators 9. One side of the separator 9 is in contact with the MEGA. The one side of the separator 9 is a gas surface in which a gas flow path for fuel gas or oxidizer gas is formed. The other side of the separator 9 is in contact with the separator of an adjacent fuel cell cell as cells are laminated. 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 comprises a separator substrate 10 and conductive films 11 (11C, 11D), such as carbon films, deposited on both sides of the separator substrate 10. One of the conductive films 11C has a uniform film thickness. Therefore, conductive film 11C can be used on the gas surface side, which directly affects power generation performance. On the other hand, conductive film 11D on the other side of the conductive film 11 has a thinner film thickness than conductive film 11C and its film thickness is not uniform. Conductive film 11D can be used on the cooling water surface side, which has less impact on power generation performance. Thus, the conductive films 11 (11C, 11D) deposited on both sides of the separator substrate 10 do not need to be the same thickness. Based on this idea, the inventors have found the following manufacturing method.

[0011] The following arrangement process is performed on multiple separator substrates 10. Subsequently, the separator substrates 10 undergo a series of processes, from a surface treatment process to a vacuum treatment process, using the film deposition apparatus 1 shown in Figure 1. The separators 9 are manufactured by the separator substrates 10 undergoing these processes.

[0012] In the placement process, multiple separator substrates 10, 10, ... are placed in each of two frames 5, 5. Each frame 5 has a gate-like shape and is fixed to a mobile platform 6. The mobile platform 6 moves together with the frames 5 within the film deposition apparatus 1, from the surface processing section 2 (described later) to the vacuum processing section 4. In this embodiment, the two frames 5 are arranged opposite each other in a direction perpendicular to the direction of movement of the mobile platform 6. Each frame 5 is provided with mounting sections 12 for attaching the separator substrates 10, spaced apart in the vertical direction, connecting both ends of the frame 5. A first virtual plane P1 is formed inside one of the two frames 5, and a second virtual plane P2 is formed inside the other frame 5. The first virtual plane P1 and the second virtual plane P2 are separated by a certain distance P.

[0013] The plurality of separator substrates 10 are composed of a plurality of first separator substrates 10A and a plurality of 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 plurality of first separator substrates 10A are arranged on a first virtual plane P1 with a certain interval D between them. The plurality of second separator substrates 10B are arranged on a second virtual plane P2 with a certain interval D between them. In this embodiment, the interval D between the plurality of first separator substrates 10A arranged on the first virtual plane P1 and the interval D between the plurality of second separator substrates 10B arranged on the second virtual plane P2 are approximately the same. Multiple mask jigs, each holding a plurality of first and second separator substrates 10A and 10B, may be arranged within the first and second virtual planes P1 and P2. The multiple mask jigs hold both edges of the plurality of first and second separator substrates 10A and 10B. Note that in Figures 2(b) and (c), for the sake of explanation, the group of first separator substrates 10A and the group of second separator substrates 10B are shown offset vertically overall. In this embodiment, the group of first separator substrates 10A and the group of second separator substrates 10B are generally aligned vertically.

[0014] As shown in Figure 2(b), the first separator substrate 10A and the second separator substrate 10B are viewed from one side Q1 perpendicular to the first virtual plane P1. In this view, the first separator substrate 10A and the second separator substrate 10B are positioned such that at least one edge of the exposed surface 10Bd of the second separator substrate 10B on the cooling water surface side is visible between the two first separator substrates 10A. Similarly, as shown in Figure 2(c), the first separator substrate 10A and the second separator substrate 10B are viewed from the other side Q2 perpendicular to the first virtual plane P1. In this view, the first separator substrate 10A and the second separator substrate 10B are positioned such that at least one edge of the exposed surface 10Ad of the first separator substrate 10A on the cooling water surface side is visible between the two second separator substrates 10B. In addition, the second separator substrate 10B, as viewed from one side Q1, and the first separator substrate 10A, as viewed from the other side Q2, may be arranged so that at least one edge is exposed, or they may be arranged so that their central portions are exposed. The multiple first and second separator substrates 10A and 10B, once positioned on each frame 5 by the arrangement process, are moved together with the mobile platform 6 from the surface treatment section 2 to the vacuum treatment section 4.

[0015] First, in this embodiment, the surface treatment step is performed in the surface treatment area 2 on the surfaces 10Ac, 10Ad, 10Bc, and 10Bd of the first and second separator substrates 10A and 10B. 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 Figure 1, a pair of plasma ion sources 7 are used for the surface treatment. After the surface treatment area 2 is brought into a vacuum state, the pair of plasma ion sources 7 irradiate the surfaces 10Ac, 10Ad, 10Bc, and 10Bd of the first and second separator substrates 10A and 10B from positions that sandwich the substrates. This allows the first and second film formation processing units 3A and 3B in the next step to exhibit an anchoring effect on the formed conductive film 11 (11C, 11D), thereby improving the adhesion of the conductive film 11 (11C, 11D) to the first and second separator substrates 10A and 10B.

[0016] The film deposition process is carried out by physical vapor deposition in the first and second film deposition processing units 3A and 3B, which constitute the film deposition 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 first film deposition processing unit 3A together with the mobile stage 6. The film deposition process is carried out using a pair of deposition sources 8, 8 positioned on the inner wall surface of the film deposition processing unit 3, on the walls facing each other along the direction of movement of the mobile stage 6 (see Figures 3(b) and (c)). The material of the deposition source 8 is a carbon material or a titanium material, and it is preferable that the material has higher corrosion resistance and higher conductivity than the material of the first and second separator substrates 10A and 10B. After the film deposition processing unit 3 is evacuated, the first and second separator substrates 10A and 10B are deposited by physical vapor deposition using a pair of deposition sources 8, 8. The material from the deposition source 8 is discharged in a relatively linear manner.

[0017] Subsequently, when moving from the first film deposition processing unit 3A to the second film deposition processing unit 3B, at least one of the multiple first separator substrates 10A and the multiple second separator substrates 10B (in this embodiment, the multiple first separator substrates 10A) is slid along the first virtual plane P1 (specifically, along the direction of movement of the mobile platform 6) while film deposition is performed by the deposition sources 8, 8 (see Figures 3(d) and (e)). Such sliding is performed by relatively sliding at least one of the pair of frames 5, 5 using a drive source such as a motor. Alternatively, for example, the above-described sliding may be performed by an interlocking mechanism linked to the mobile platform 6.

[0018] According to this embodiment, the first and second separator substrates 10A and 10B are arranged such that, when viewed from one side Q1 perpendicular to the first virtual plane P1, a portion of the cooling water surface 10Bd of the second separator substrate 10B is exposed between the first separator substrates 10A. A conductive film 11C is formed on the gas surface 10Ac of the first separator substrate 10A facing one side Q1 by the deposition source 8 on one side Q1 (see Figure 3(a)). At the same time, material from the deposition source 8 on one side Q1 passes between the first separator substrates 10A, and a conductive film 11D is formed on the cooling water surface 10Bd of the second separator substrate 10B. Here, as shown in Figures 2(b) to 2(d), in the film formation process, multiple first separator substrates 10A are slid along the first virtual plane P1 relative to multiple second separator substrates 10B. Compared to the case where film is formed without sliding (see Figure 3(c)), the material from the deposition source 8 wraps around to the first virtual plane P1, and the material from the deposition source 8 reaches the second separator substrates 10B directly, allowing for the formation of a conductive film 11D with a more uniform thickness (see Figure 3(b)).

[0019] Similarly, when viewed from the other side Q2 in the orthogonal direction, the first and second separator substrates 10A and 10B are arranged such that a part of the surface 10Ad on the cooling water surface side of the first separator substrate 10A is exposed between the second separator substrates 10B. A conductive film 11C is formed on the gas surface side surface 10Bc of the second separator substrate 10B facing the other side Q2 by the vapor deposition source 8 on the other side Q2 (see Fig. 3(a)). At the same time, the material from the vapor 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 on the cooling water surface side of the first separator substrate 10A. Similarly here, as shown in Figs. 2(c) to 2(e), by sliding a plurality of the first separator substrates 10A in the film formation process, the intrusion of the material of the vapor deposition source 8 into the second virtual plane P2 is suppressed, and the material of the vapor deposition source 8 directly reaches the first separator substrate 10A, so that a conductive film 11D with a more uniform film thickness can be formed (see Fig. 3(b)).

[0020] In this way, the conductive films 11 (11C, 11D) can be formed on both sides of the plurality of first and second separator substrates 10A and 10B respectively arranged on the first and second virtual planes P1 and P2 with the pair of vapor deposition sources 8 interposed therebetween. 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 and 10B that can be formed in one time can be increased. A conductive film 11D with a thinner film thickness than the conductive film 11C is formed on the surface 10Ad on the cooling water surface side of the first separator substrate 10A facing the other side Q2 in the orthogonal direction to the first virtual plane P1. The same applies to the conductive films 11C and 11D formed on the second separator substrate 10B. However, since the conductive film 11D formed on the first and second separator substrates 10A and 10B is used on the cooling water surface side, it hardly affects the power generation characteristics of the fuel cell.

[0021] Finally, the first and second separator substrates 10A and 10B (separators 9) that have undergone film deposition treatment pass through the film deposition processing unit 3 and then move to the vacuum processing unit 4 together with the transfer table 6. Any particles other than the conductive film 11 (11C, 11D) attached to the first and second separator substrates 10A and 10B that have moved into the vacuum processing unit 4 are removed when the vacuum is created in the vacuum processing unit 4. [Explanation of Symbols]

[0022] 1: Film deposition apparatus, 2: Surface treatment section, 3: Film deposition section, 4: Vacuum section, 5: Frame, 6: Mobile platform, 7: Plasma ion source, 8: Evaporation source, 9: Separator for fuel cell, 10: Separator substrate, 10A: First separator substrate, 10B: Second separator substrate, 11: Conductive film, 12: Mounting section

Claims

[Claim 1] A method for manufacturing a fuel cell separator, wherein a conductive film is deposited on both sides of multiple separator substrates placed in a film deposition apparatus by physical vapor deposition, The method for manufacturing the separator is as follows: Among the plurality of separator substrates, a plurality of first separator substrates are arranged in the film-forming apparatus at regular intervals on the first virtual plane. The process includes a placement step of arranging a plurality of second separator substrates from the plurality of separator substrates within the film-forming apparatus, on a second virtual plane spaced at a certain distance from the first virtual plane, with a certain interval between them. In the arrangement step, the first separator substrate and the second separator substrate are arranged such that, when viewed from one side perpendicular to the first virtual plane, a portion of the surface of the second separator substrate is exposed between the first separator substrates, and when viewed from the other side perpendicular to the first separator substrate, a portion of the surface of the first separator substrate is exposed between the second separator substrates. A method for manufacturing a fuel cell separator, characterized in that, while each of the plurality of first separator substrates and the plurality of second separator substrates maintains the state of being spaced apart, at least one of the plurality of first separator substrates and the plurality of second separator substrates is slid along the first or second virtual plane, and the conductive film is deposited on both sides of the first separator substrate and the second separator substrate by a pair of deposition sources arranged in the film deposition apparatus so as to sandwich the first and second virtual planes.

Images