SEPARATOR AGGREGATE MANUFACTURING METHOD, FUEL CELL MANUFACTURING METHOD, AND SEPARATOR AGGREGATE MANUFACTURING APPARATUS

Abstract

To manufacture products that hardly cause damage due to vibration or shock, that can be miniaturized, and that have a sufficient high degree of freedom in design.SOLUTION: A separator assembly 51, in which separators 61a, 61b where respective grooves A, B that allow gas for power generation to pass therethrough are formed and a separator 62 where a groove C that allows a cooling fluid to pass therethrough is formed are integrated, is manufactured by performing in the following order: first processing of housing a laminate 55a (laminate 55b) in a processing tank, the laminate being formed by layering plates 71-73, 81, 82, and increasing the degree of vacuum in the processing tank; second processing of increasing the temperature of the laminate 55b to a first temperature to reduce and remove a passive film of each plate; third processing of increasing the temperature of the laminate 55b to a second temperature higher than the first temperature while the laminate 55b is pressurized, thereby subjecting each plate to diffusion bonding; and fourth processing of lowering the temperature of the laminate 55b and lowering the degree of vacuum in the processing tank.SELECTED DRAWING: Figure 9

Description

[Technical field]

[0001] The present invention relates to a separator assembly manufacturing method and separator assembly manufacturing apparatus for manufacturing a separator assembly for a fuel cell having grooves through which gas for power generation can pass, and a fuel cell manufacturing method for manufacturing fuel cell units using a separator assembly manufactured by such a separator assembly manufacturing method. [Background technology]

[0002] A solid polymer electrolyte fuel cell is configured to include an electrolyte membrane, a pair of electrodes, and a pair of separators. In this case, it is known that a fuel cell with good power generation efficiency can be manufactured by adopting a carbon separator mainly made of carbon. A method for manufacturing this carbon separator is known in which a kneaded mixture of carbon and thermosetting resin is injected into a mold, the mixture is heated to a temperature at which the thermosetting resin melts, and then the mixture is compressed and heated to a temperature at which the thermosetting resin hardens to harden it. However, when manufacturing a separator using this manufacturing method, the molding material (kneaded material) injected into the mold contains a large amount of carbon compared to when manufacturing a general resin molded product, so the viscosity of the molding material is high and its fluidity is poor, and the molding material may solidify before filling every corner of the cavity in the mold. This may make it difficult to manufacture a separator with a desired shape.

[0003] On the other hand, the following patent document discloses a method and an apparatus for forming a carbon separator for a fuel cell, which is made to solve the above problems. In this method and apparatus, a carbon resin material is formed by applying a resin material for molding (thermosetting resin material) to the surface of a carbon powder made of a granular solid to form a coating layer, and a liquid (water, alcohol, Fluorinert, etc.) for improving the fluidity is mixed and kneaded to form a molding material (kneaded material) into a mold, and the liquid in the injected molding material (kneaded material) is discharged outside the mold through a small hole provided in the mold. As a result, the molding material has high fluidity at the time of injection into the mold, so that the molding material can be filled into every corner of the mold. This makes it possible to manufacture a carbon separator of a desired shape. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2007-207684 A (pages 4-9, figures 1-9) Summary of the Invention [Problem to be solved by the invention]

[0005] However, the carbon separators (hereinafter simply referred to as "separators") manufactured by the manufacturing methods and manufacturing apparatuses disclosed in the above patent documents have the following problems to be solved. Specifically, the separator molding apparatus and molding method disclosed in the above patent documents employ a configuration and method in which a carbon resin material (molding material) is injected into a mold and hardened. This makes it possible to reliably manufacture separators of the desired shape, compared to conventional molding apparatuses and molding methods.

[0006] However, although molded products manufactured by this type of molding method and molding apparatus can have a certain degree of hardness depending on the type of resin material used in the molding material, it is known that the molding material contains granular solids (carbon powder) and therefore has low toughness, making it prone to cracking when subjected to vibration or impact. For this reason, in fuel cell cells manufactured using separators molded by this molding apparatus and molding method, cracks may occur in the separator due to vibration or impact applied to the power generation device, and when cracks occur in the hydrogen cell, this may lead to hydrogen gas leakage, and when cracks occur in the air separator, the amount of oxygen to react with hydrogen gas may decrease, causing a decrease in power generation efficiency.

[0007] Furthermore, to prevent cracks caused by vibration or impact, the separator needs to be formed to a sufficient thickness to ensure the physical strength of the separator itself. This makes it difficult to miniaturize fuel cells manufactured using separators molded by this molding device and molding method. Furthermore, in the separator molding device and molding method disclosed in the above patent document, the shape of the molded product is limited to a "shape that can be removed from a mold (a shape that can be demolded)." This also creates the problem of low freedom in designing the shape of the separator.

[0008] In addition, in a manufacturing method in which a carbon resin material (molding material) is injected into a mold and hardened, a groove-shaped flow path exposed on the surface of the product can be formed, but a closed flow path cannot be formed within the thickness of the product. Therefore, when a separator assembly is manufactured by integrating a separator having a flow path for passing hydrogen gas or the like and a separator having a closed flow path for passing a cooling fluid or the like, using the manufacturing method disclosed in the above patent document, it is necessary to separately manufacture a member for forming the groove-shaped flow path and a member for blocking the opening portion of the groove-shaped flow path for the separator having the closed flow path, and integrate the two members to form the closed flow path. This makes it difficult to reduce the manufacturing cost of such a separator assembly.

[0009] The present invention has been made in consideration of the above-mentioned problems to be solved, and has as its main object to provide a separator assembly manufacturing method, a fuel cell manufacturing method, and a separator assembly manufacturing apparatus that are capable of manufacturing products that are less susceptible to damage caused by vibration or impact, can be made compact, and have a sufficiently high degree of design freedom. Another object of the present invention is to provide a separator assembly manufacturing method and a separator assembly manufacturing apparatus that can reduce the manufacturing cost of a separator assembly that has separators that allow a cooling fluid to pass through. [Means for solving the problem]

[0010] In order to achieve the above object, a separator assembly manufacturing method according to claim 1 is a method for manufacturing a separator assembly in which a separator A provided with a groove portion A for passing a generating gas A, a separator B provided with a groove portion B for passing a generating gas B to be reacted with the generating gas A, and a separator C provided with a groove portion C for passing a cooling fluid and cooling at least one of the separator A and the separator B are integrated together, the method comprising the steps of: a metal plate A1 provided with a slit A passing through in the plate thickness direction; a metal plate A2 provided with a blocking portion A that closes one end of the slit A in the plate thickness direction; a metal plate B1 provided with a slit B passing through in the plate thickness direction; a metal plate B2 provided with a blocking portion B that closes one end of the slit B in the plate thickness direction; a metal plate C1 provided with a slit C passing through in the plate thickness direction; a first process for increasing the degree of vacuum in the treatment tank; a second process for increasing the temperature of the stack to a predetermined first temperature to reduce and remove the passivation films of the plurality of plates; a third process for increasing the temperature of the stack to a predetermined second temperature higher than the first temperature while pressurizing the stack with a predetermined pressure, thereby diffusion bonding the plurality of plates; and a fourth process for decreasing the temperature of the stack and decreasing the degree of vacuum in the treatment tank, in that order, to produce the separator assembly in which the separator A in which the groove portion A is defined by the slit A and the blocking portion A, the separator B in which the groove portion B is defined by the slit B and the blocking portion B, and the separator C in which the groove portion C is defined by the slit C and the blocking portion C are integrated together.

[0011] A separator assembly manufacturing method according to a second aspect of the present invention is the separator assembly manufacturing method according to the first aspect, wherein in the fourth treatment, nitrogen is caused to flow into the treatment tank to reduce the degree of vacuum in the treatment tank.

[0012] A separator assembly manufacturing method according to a third aspect of the present invention is the separator assembly manufacturing method according to the first aspect, wherein in the fourth treatment, gas in the treatment tank is blown toward the laminate to lower the temperature of the laminate.

[0013] The separator assembly manufacturing method according to claim 4 is a separator assembly manufacturing method for manufacturing a separator assembly in which a separator A having a groove portion A for passing a generating gas A, a separator B having a groove portion B for passing a generating gas B to be reacted with the generating gas A, and a separator C having a groove portion C for passing a cooling fluid and cooling at least one of the separator A and the separator B are integrated together, the method comprising the steps of: manufacturing a separator assembly in which a separator A having a groove portion A for passing a generating gas A, a separator B having a groove portion B for passing a generating gas B to be reacted with the generating gas A, and a separator C having a groove portion C for passing a cooling fluid and cooling at least one of the separator A and the separator B, the method comprising the steps of: manufacturing a separator assembly in which a separator A having a groove portion A for passing a generating gas A, a separator B having a groove portion C for passing a cooling fluid, The first laminate is formed by stacking a plurality of first plates, the first plates including at least a metal plate A2 having a blocking portion A blocking one of the first plates, in the thickness direction, in a first treatment tank. The first laminate is placed in the first treatment tank, and the degree of vacuum in the first treatment tank is increased in a process 1A. The temperature of the first laminate is increased to a predetermined first temperature to reduce and remove the passivation film of the plurality of first plates. The second laminate is pressurized with a predetermined pressure and the temperature of the first laminate is increased to a predetermined second temperature higher than the first temperature to diffusion bond the plurality of first plates. and a process 4A for lowering the temperature of the first laminate and lowering the degree of vacuum in the first treatment tank in this order, thereby manufacturing the separator A in which the groove portion A is constituted by the slits A and the blocking portion A, and manufacturing the separator A in which the separator A is constituted by the metal plate B1 having a slit B penetrating in the plate thickness direction, a metal plate B2 having a blocking portion B blocking one end of the slit B in the plate thickness direction, a metal plate C1 having a slit C penetrating in the plate thickness direction, and a blocking portion B blocking one end of the slit C in the plate thickness direction. a process 1B in which a second laminate is placed in a second treatment tank, the second laminate being formed by stacking a plurality of second plates, the second laminate including at least a metal plate C2 having a blocking portion C formed thereon, in the thickness direction, and the degree of vacuum in the second treatment tank is increased; a process 2B in which a temperature of the second laminate is increased to a predetermined third temperature to reduce and remove a passivation film of the plurality of second plates; and a process 3B in which a temperature of the second laminate is increased to a predetermined fourth temperature higher than the third temperature while the second laminate is pressurized with a predetermined pressure, thereby diffusion bonding the plurality of plates.By performing a process 4B in this order, the temperature of the second laminate is lowered and the degree of vacuum in the second treatment tank is lowered, thereby manufacturing an intermediate body in which the separator B in which the groove portion B is formed by the slits B and the blocking portions B and the separator C in which the groove portion C is formed by the slits C and the blocking portions C are integrated, and the separator A, the sheet-like member and the intermediate body are integrated in a state in which a conductive and elastically deformable sheet-like member is sandwiched between the separator A and the intermediate body, thereby manufacturing the separator assembly.

[0014] The separator assembly manufacturing method of claim 5 is the separator assembly manufacturing method of claim 4, in which in process 4A, nitrogen is flowed into the first treatment tank to reduce the degree of vacuum in the first treatment tank, and in process 4B, nitrogen is flowed into the second treatment tank to reduce the degree of vacuum in the second treatment tank.

[0015] The separator assembly manufacturing method of claim 6 is the separator assembly manufacturing method of claim 4, in which in process 4A, gas in the first treatment tank is blown toward the first laminate to lower the temperature of the first laminate, and in process 4B, gas in the second treatment tank is blown toward the second laminate to lower the temperature of the second laminate.

[0016] A separator assembly manufacturing method according to claim 7 is a separator assembly manufacturing method for manufacturing a separator assembly in which a separator A having a groove portion A for passing a generating gas A, a separator B having a groove portion B for passing a generating gas B to be reacted with the generating gas A, and a separator C having a groove portion C for passing a cooling fluid and cooling at least one of the separators A and B are integrated together, the method comprising the steps of: manufacturing a separator assembly including a metal plate A1 having a slit A penetrating therethrough in a plate thickness direction; The laminate A, which is a stack of a plurality of plates A including at least a metal plate A2 having a blocking portion A for blocking the plate A, is placed in a treatment tank A, and a process A1 is performed to increase the degree of vacuum in the treatment tank A; a process A2 is performed to reduce and remove the passivation film of the plurality of plates A by increasing the temperature of the laminate A to a predetermined temperature 1A; a process A3 is performed to diffuse-bond the plurality of plates A by increasing the temperature of the laminate A to a predetermined temperature 2A higher than the temperature 1A while pressurizing the laminate A with a predetermined pressure; and a process A4 is performed to reduce the temperature of the laminate A and the temperature of the laminate A is reduced. and a process A4 for reducing the degree of vacuum in the treatment tank A are carried out in this order to manufacture the separator A in which the groove portion A is formed by the slit A and the blocking portion A. The separator A is manufactured by stacking a plurality of plates B, each plate B including at least a metal plate B1 having a slit B penetrating therethrough in the thickness direction and a metal plate B2 having a blocking portion B blocking one end of the slit B in the thickness direction, in the treatment tank B to form a stack B, and a process B1 for increasing the degree of vacuum in the treatment tank B and a process A2 for increasing the temperature of the stack B to a predetermined temperature 1B to form the plurality of plates B. a process B2 for reducing and removing the passivation film of the plate B; a process B3 for increasing the temperature of the laminate B to a predefined temperature 2B higher than the temperature 1B while pressing the laminate B with a predefined pressure, thereby diffusion bonding the plurality of plates B; and a process B4 for decreasing the temperature of the laminate B and decreasing the degree of vacuum in the treatment tank B, in this order, to produce the separator B in which the groove portion B is formed by the slits B and the blocking portions B, and a metal plate C1 having a slit C penetrating in the plate thickness direction,A laminate C in which a plurality of plates C, each including at least a metal plate C2 having a blocking portion C for blocking one end of the slit C in the thickness direction, are stacked in the thickness direction of the plate, is placed in a treatment tank C, and a process C1 is performed to increase the degree of vacuum in the treatment tank C; a process C2 is performed to reduce and remove the passivation film of the plurality of plates C by increasing the temperature of the laminate C to a predetermined temperature 1C; a process C3 is performed to diffusion-bond the plurality of plates C by increasing the temperature of the laminate C to a predetermined temperature 2C that is higher than the temperature 1C while the laminate C is pressurized with a predetermined pressure; and and a process C4 for reducing the degree of vacuum in the treatment tank C are carried out in this order to produce the separator C in which the groove portion C is formed by the slits C and the blocking portions C, and a first sheet-like member that is conductive and elastically deformable is sandwiched between the separator A and the separator C, and a second sheet-like member that is conductive and elastically deformable is sandwiched between the separator B and the separator C, and the separator A, the first sheet-like member, the separator C, the second sheet-like member and the separator B are integrated to produce the separator assembly.

[0017] The separator assembly manufacturing method of claim 8 is the separator assembly manufacturing method of claim 7, wherein in process A4, nitrogen is flowed into treatment tank A to reduce the degree of vacuum in treatment tank A, in process B4, nitrogen is flowed into treatment tank B to reduce the degree of vacuum in treatment tank B, and in process C4, nitrogen is flowed into treatment tank C to reduce the degree of vacuum in treatment tank C.

[0018] The separator assembly manufacturing method of claim 9 is the separator assembly manufacturing method of claim 7, in which in process A4, gas in the treatment tank A is blown toward the stack A to lower the temperature of the stack A, in process B4, gas in the treatment tank B is blown toward the stack B to lower the temperature of the stack B, and in process C4, gas in the treatment tank C is blown toward the stack C to lower the temperature of the stack C.

[0019] The fuel cell manufacturing method described in claim 10 manufactures a fuel cell by sandwiching a fuel cell membrane electrode assembly between a plurality of separator assemblies manufactured by the separator assembly manufacturing method described in any one of claims 1 to 9, and integrating the separator assemblies and the fuel cell membrane electrode assembly in a state where the separator assemblies and the fuel cell membrane electrode assembly are integrated.

[0020] The separator assembly manufacturing apparatus according to claim 11 is an apparatus for manufacturing a separator assembly in which a separator A having a groove portion A for passing a generating gas A, a separator B having a groove portion B for passing a generating gas B to be reacted with the generating gas A, and a separator C having a groove portion C for passing a cooling fluid and cooling at least one of the separator A and the separator B are integrated together, the apparatus comprising: a metal plate A1 having a slit A penetrating therethrough in a plate thickness direction; The present invention relates to a processing tank capable of accommodating a stack of a plurality of plate bodies, the stack of plate bodies including at least a metal plate A2 having a blocking portion A blocking one end of the slit B in the thickness direction, a metal plate B1 having a slit B penetrating in the thickness direction, a metal plate B2 having a blocking portion B blocking one end of the slit B in the thickness direction, a metal plate C1 having a slit C penetrating in the thickness direction, and a metal plate C2 having a blocking portion C blocking one end of the slit C in the thickness direction, a vacuum adjustment unit that adjusts the vacuum level in the processing tank, and a metal plate accommodated in the processing tank. The apparatus includes a temperature adjustment unit that adjusts the temperature of the laminate, a pressurizing unit that pressurizes the laminate contained in the treatment tank in the plate thickness direction, and a control unit that controls the operation of the vacuum adjustment unit, the temperature adjustment unit, and the pressurizing unit, and the control unit performs a first process of controlling the vacuum adjustment unit to increase the vacuum in the treatment tank in which the laminate is contained, a second process of controlling the temperature adjustment unit to increase the temperature of the laminate to a predetermined first temperature and reduce and remove the passivation film of the plurality of plates, and a third process of pressing the laminate to the pressurizing unit with a predetermined pressure. a third process of controlling the temperature adjustment unit to increase the temperature of the laminate to a predefined second temperature higher than the first temperature in a state in which the plurality of plates are bonded to each other through diffusion bonding, and a fourth process of controlling the temperature adjustment unit to decrease the temperature of the laminate and controlling the vacuum adjustment unit to decrease the degree of vacuum in the treatment tank in this order, thereby producing the separator A in which the groove portion A is formed by the slit A and the blocking portion A, the separator B in which the groove portion B is formed by the slit B and the blocking portion B,and a separator assembly is manufactured by integrating the separator C having the groove portion C formed by the slit C and the blocking portion C. Effect of the Invention

[0021] The separator assembly manufacturing method according to claim 1 includes a first process of placing a laminate in a treatment tank, the laminate being formed by stacking a plurality of plates in a thickness direction, the laminate including at least a metal plate A1 having a slit A penetrating therethrough in the thickness direction, a metal plate A2 having a blocking portion A closing one end of the slit A in the thickness direction, a metal plate B1 having a slit B penetrating therethrough in the thickness direction, a metal plate B2 having a blocking portion B closing one end of the slit B in the thickness direction, a metal plate C1 having a slit C penetrating therethrough in the thickness direction, and a metal plate C2 having a blocking portion C closing one end of the slit C in the thickness direction, and increasing the degree of vacuum in the treatment tank; and a second process of stacking a plurality of plates in a thickness direction, the laminate being formed by stacking a plurality of plates in a thickness direction, the metal plate B1 having a slit B penetrating therethrough in the thickness direction, a metal plate C2 having a slit C penetrating therethrough in the thickness direction, and a metal plate C2 having a blocking portion C closing one end of the slit C in the thickness direction. A second process is performed in which the temperature of the laminate is raised to a predetermined second temperature that is higher than the first temperature while the laminate is pressurized with a predetermined pressure, thereby diffusion bonding the multiple plates. A fourth process is performed in this order to reduce and remove the passive film of the multiple plates. The fourth process is performed in which the temperature of the laminate is lowered and the degree of vacuum in the treatment tank is reduced. This produces a separator assembly that integrates separator A, in which separator B has groove portion A formed by slit A and blocking portion A, separator B, in which groove portion B has groove portion B formed by slit B and blocking portion B, and separator C, in which groove portion C has groove portion C formed by slit C and blocking portion C.

[0022] In addition, in a fuel cell manufacturing method described in claim 10, a fuel cell is manufactured by integrating a fuel cell membrane electrode assembly and a fuel cell membrane electrode assembly in a state where the fuel cell membrane electrode assembly is sandwiched between a plurality of separator assemblies manufactured by the separator assembly manufacturing method described above. In addition, in a separator assembly manufacturing apparatus described in claim 11, the apparatus includes a treatment tank capable of accommodating the stack, a vacuum adjustment unit that adjusts the vacuum level in the treatment tank, a temperature adjustment unit that adjusts the temperature of the stack accommodated in the treatment tank, a pressurizing unit that pressurizes the stack accommodated in the treatment tank in the plate thickness direction, and a control unit that controls the operation of the vacuum adjustment unit, the temperature adjustment unit, and the pressurizing unit, and the control unit performs the first process, the second process, the third process, and the fourth process in this order to manufacture a separator assembly.

[0023] Therefore, according to the separator assembly manufacturing method of claim 1, the fuel cell manufacturing method of claim 10, and the separator assembly manufacturing apparatus of claim 11, a separator assembly having sufficiently high hardness, rigidity, and toughness can be manufactured by using a metal plate as a material, compared with a carbon separator manufactured by a molding method using a mixture of a carbon resin material in which a thermosetting resin material is applied to the surface of carbon powder to form a coating layer, and a liquid such as water is mixed and kneaded. This makes it possible to provide a separator assembly and a fuel cell that are less likely to be damaged due to vibration or impact. In addition, since it is not necessary to make the thickness of each part excessively thick in order to ensure the physical strength of the separator assembly, the separator assembly and the fuel cell can be sufficiently miniaturized. In addition, since it is not necessary to design the shape taking into account demolding (removal from the mold after molding is completed), the degree of freedom in design is sufficiently high, and the separator can be manufactured in any shape according to the required power generation capacity and use. Furthermore, by carrying out a series of processes from the first process to the fourth process, it is possible to form, within the thickness of the separator assembly, a sealed flow path in which the opening portion of the groove portion C consisting of the slit C of the metal plate C1 and the blocking portion C of the metal plate C2 is blocked by another plate body, in addition to the groove portions A and B. This eliminates the need for a process of forming and integrating a plurality of members to form a sealed flow path, and as a result, it is possible to sufficiently reduce the manufacturing cost of the separator assembly.

[0024] In the separator assembly manufacturing method according to claim 2, nitrogen is introduced into the treatment tank in the fourth treatment to reduce the degree of vacuum in the treatment tank. Therefore, the separator assembly manufacturing method according to claim 2 and the fuel cell manufacturing method for manufacturing a fuel cell using a separator assembly manufactured according to the separator assembly manufacturing method can sufficiently reduce the amount of oxygen that comes into contact with the laminate heated to a high temperature in the third treatment, unlike a manufacturing method in which air (atmosphere) is introduced into the treatment tank to reduce the degree of vacuum, and therefore it is possible to suitably prevent the surface of the laminate from being oxidized and a passivation film from being formed. In addition, since nitrogen is relatively inexpensive, has low danger at high temperatures, and is harmless even if released into the atmosphere when the door of the treatment tank is opened after the treatment is completed, it is possible to prevent the manufacturing costs of the separator assembly from rising, the occurrence of accidents during manufacturing, and the occurrence of environmental damage.

[0025] In the separator assembly manufacturing method recited in claim 3, the temperature of the stack is lowered by blowing gas in the treatment tank toward the stack in the fourth treatment. Therefore, according to the separator assembly manufacturing method recited in claim 3 and the fuel cell manufacturing method for manufacturing a fuel cell using a separator assembly manufactured according to the separator assembly manufacturing method, the amount of temperature drop in each part of the stack can be made uniform and the thermal shrinkage state of each part can be made similar, thereby preferably preventing unintended deformation or cracks from occurring in the separator assembly.

[0026] In the method for producing a separator assembly according to claim 4, a first laminate is formed by stacking a plurality of first plates in a thickness direction, the first laminate including at least a metal plate A1 having a slit A penetrating therethrough in a thickness direction and a metal plate A2 having a blocking portion A blocking one end of the slit A in the thickness direction, in a first treatment tank, and the first treatment tank is subjected to a process 1A of increasing the degree of vacuum in the first treatment tank, a process 2A of increasing the temperature of the first laminate to a predetermined first temperature to reduce and remove the passivation film of the plurality of first plates, and a process 3A of reducing the passivation film of the first laminate in a state where the first laminate is pressurized with a predetermined pressure. The process 3A is performed in this order to increase the temperature of the first laminate to a predefined second temperature higher than the temperature of the first laminate to diffusion bond the plurality of first plates, and the process 4A is performed in this order to decrease the temperature of the first laminate and to decrease the degree of vacuum in the first treatment tank. In this process, a separator A having a groove portion A formed by slits A and blocking portions A is manufactured. The separator A has a metal plate B1 having a slit B penetrating in the plate thickness direction, a metal plate B2 having a blocking portion B blocking one end of the slit B in the plate thickness direction, and a slit C penetrating in the plate thickness direction. and a metal plate C2 having a blocking portion C that blocks one end of the slit C in the thickness direction, the second laminate is placed in a second treatment tank, and a process 1B is performed to increase the degree of vacuum in the second treatment tank; a process 2B is performed to reduce and remove the passivation film of the second plates by increasing the temperature of the second laminate to a predetermined third temperature; and a process 2C is performed to reduce and remove the passivation film of the second plates by increasing the temperature of the second laminate to a predetermined fourth temperature that is higher than the third temperature while the second laminate is pressurized with a predetermined pressure. By carrying out process 3B of diffusion bonding multiple plates and process 4B of lowering the temperature of the second laminate and reducing the degree of vacuum in the second treatment tank in that order, an intermediate is produced in which separator B, in which groove portion B is formed by slits B and blocking portions B, and separator C, in which groove portion C is formed by slits C and blocking portions C, are integrated, and a separator assembly is produced by integrating separator A, the sheet-like member, and the intermediate with a conductive and elastically deformable sheet-like member sandwiched between separator A and the intermediate.

[0027] In addition, in a fuel cell manufacturing method described in claim 10, a fuel cell is manufactured by sandwiching a fuel cell membrane electrode assembly between a plurality of separator assemblies manufactured by the above-mentioned separator assembly manufacturing method, and integrating each separator assemblies and the fuel cell membrane electrode assembly in a state where the separator assemblies and the fuel cell membrane electrode assembly are integrated.

[0028] Therefore, according to the separator assembly manufacturing method of claim 4 and the fuel cell manufacturing method of claim 10, a separator assembly having sufficiently high hardness, rigidity and toughness can be manufactured by using a metal plate as a material, compared with a carbon separator manufactured by a molding method using a mixture of a carbon resin material in which a thermosetting resin material is applied to the surface of carbon powder to form a coating layer, and a liquid such as water is mixed and kneaded. This makes it possible to provide a separator assembly and a fuel cell that are less likely to be damaged due to vibration or impact. In addition, since it is not necessary to make the thickness of each part excessively thick in order to ensure the physical strength of the separator assembly, the separator assembly and the fuel cell can be sufficiently miniaturized. In addition, since it is not necessary to design the shape taking into account demolding (removal from the mold after molding is completed), the degree of freedom in design is sufficiently high, and the separator can be manufactured in any shape according to the required power generation capacity and use.

[0029] In addition, in the separator assembly manufacturing method described in claim 5, nitrogen is introduced into the first treatment tank in the process 4A to reduce the degree of vacuum in the first treatment tank, and nitrogen is introduced into the second treatment tank in the process 4B to reduce the degree of vacuum in the second treatment tank. Therefore, according to the separator assembly manufacturing method described in claim 5 and the fuel cell manufacturing method for manufacturing a fuel cell using a separator assembly manufactured according to the separator assembly manufacturing method, unlike a manufacturing method in which air (atmosphere) is introduced into the treatment tank to reduce the degree of vacuum, the amount of oxygen that comes into contact with the laminate heated to a high temperature in processes 3A and 3B can be sufficiently reduced, and it is possible to suitably avoid a situation in which the surface of the laminate is oxidized and a passivation film is formed. In addition, since nitrogen is relatively inexpensive, has low danger at high temperatures, and is harmless even if it is released into the atmosphere when the door of the treatment tank is opened after the treatment is completed, it is possible to avoid a situation in which the manufacturing cost of the separator assembly rises, accidents occur during manufacturing, and environmental damage occurs.

[0030] In addition, in the separator assembly manufacturing method recited in claim 6, in process 4A, gas in a first treatment tank is blown toward the first stack to lower the temperature of the first stack, and in process 4B, gas in a second treatment tank is blown toward the second stack to lower the temperature of the second stack. Therefore, according to the separator assembly manufacturing method recited in claim 6 and the fuel cell manufacturing method for manufacturing a fuel cell using a separator assembly manufactured according to the separator assembly manufacturing method, the amount of temperature drop in each part of the stack can be made uniform and the thermal shrinkage state of each part can be made similar, thereby making it possible to suitably avoid unintended deformation or cracks in the separator assembly.

[0031] In the separator assembly manufacturing method according to claim 7, a laminate A is placed in a treatment tank A, and the laminate A is made by stacking a plurality of plates A in a thickness direction, the plurality of plates A including at least a metal plate A1 having a slit A penetrating therethrough in a thickness direction and a metal plate A2 having a blocking portion A blocking one end of the slit A in the thickness direction. The laminate A is placed in a treatment tank A, and the laminate A includes a process A1 for increasing the degree of vacuum in the treatment tank A, a process A2 for increasing the temperature of the laminate A to a predetermined temperature 1A to reduce and remove the passivation film of the plurality of plates A, and a process A3 for reducing and removing the passivation film of the plurality of plates A by increasing the temperature of the laminate A to a predetermined temperature 1A while the laminate A is pressurized with a predetermined pressure. A separator A having a groove A formed by slits A and blocking portions A is manufactured by carrying out a process A3 in which the temperature of the laminate A is increased to 2A to diffusion-bond the plurality of plates A, and a process A4 in which the temperature of the laminate A is decreased and the degree of vacuum in the treatment tank A is decreased in this order, and a laminate B in which a plurality of plates B including at least a metal plate B1 having a slit B penetrating therethrough in the thickness direction and a metal plate B2 having a blocking portion B blocking one end of the slit B in the thickness direction are stacked in the thickness direction is placed in the treatment tank B, and the degree of vacuum in the treatment tank B is increased. By carrying out the following steps in this order: process B1; process B2 for increasing the temperature of the laminate B to a predefined temperature 1B to reduce and remove the passivation film of the plurality of plates B; process B3 for increasing the temperature of the laminate B to a predefined temperature 2B higher than the temperature 1B while pressing the laminate B with a predefined pressure, thereby diffusion bonding the plurality of plates B; and process B4 for decreasing the temperature of the laminate B and decreasing the degree of vacuum in the treatment tank B, a separator B having a groove portion B formed by slits B and blocking portions B is manufactured. a process C1 for placing a laminate C in a treatment tank C, the laminate C being formed by stacking a plurality of plates C in a thickness direction, the plurality of plates C including at least a metal plate C1 having a slit C formed therein and a metal plate C2 having a blocking portion C for blocking one end of the slit C in the thickness direction, and increasing the degree of vacuum in the treatment tank C; a process C2 for increasing the temperature of the laminate C to a predetermined temperature 1C to reduce and remove the passivation film of the plurality of plates C; and a process C3 for increasing the temperature of the laminate C to a predetermined temperature 2C higher than the temperature 1C while pressurizing the laminate C with a predetermined pressure, thereby diffusion bonding the plurality of plates C.By carrying out a process C3 in this order, a separator C having grooves C formed by slits C and blocking portions C is manufactured, and a separator assembly is manufactured by integrating separator A, the first sheet-like member, separator C, the second sheet-like member, and separator B in a state in which a conductive and elastically deformable second sheet-like member is sandwiched between separator B and separator C.

[0032] In addition, in a fuel cell manufacturing method described in claim 10, a fuel cell is manufactured by sandwiching a fuel cell membrane electrode assembly between a plurality of separator assemblies manufactured by the above-mentioned separator assembly manufacturing method, and integrating each separator assemblies and the fuel cell membrane electrode assembly in a state where the separator assemblies and the fuel cell membrane electrode assembly are integrated.

[0033] Therefore, according to the separator assembly manufacturing method of claim 7 and the fuel cell manufacturing method of claim 10, a separator assembly having sufficiently high hardness, rigidity and toughness can be manufactured by using a metal plate as a material, compared with a carbon separator manufactured by a molding method using a mixture of a carbon resin material in which a thermosetting resin material is applied to the surface of carbon powder to form a coating layer, and a liquid such as water is mixed and kneaded. This makes it possible to provide a separator assembly and a fuel cell that are less likely to be damaged due to vibration or impact. In addition, since it is not necessary to make the thickness of each part excessively thick in order to ensure the physical strength of the separator assembly, the separator assembly and the fuel cell can be sufficiently miniaturized. In addition, since it is not necessary to design the shape taking into account demolding (removal from the mold after molding is completed), the degree of freedom in design is sufficiently high, and the separator can be manufactured in any shape according to the required power generation capacity and use.

[0034] In the separator assembly manufacturing method according to claim 8, nitrogen is introduced into the treatment tank A in the process A4 to reduce the degree of vacuum in the treatment tank A, nitrogen is introduced into the treatment tank B in the process B4 to reduce the degree of vacuum in the treatment tank B, and nitrogen is introduced into the treatment tank C in the process C4 to reduce the degree of vacuum in the treatment tank C. Therefore, according to the separator assembly manufacturing method according to claim 8 and the fuel cell manufacturing method for manufacturing a fuel cell using a separator assembly manufactured according to the separator assembly manufacturing method, unlike the manufacturing method in which air (atmosphere) is introduced into the treatment tank to reduce the degree of vacuum, the amount of oxygen that comes into contact with the laminate heated to a high temperature in the processes A3, B3, and C3 can be sufficiently reduced, and the surface of the laminate is oxidized to preferably prevent the formation of a passivation film. In addition, since nitrogen is relatively inexpensive, has low danger at high temperatures, and is harmless even if released into the atmosphere when the door of the treatment tank is opened after the treatment is completed, it is possible to avoid a situation in which the manufacturing cost of the separator assembly rises, accidents occur during manufacturing, and environmental damage occurs.

[0035] Furthermore, in the separator assembly manufacturing method recited in claim 9, in process A4, gas in treatment tank A is blown toward stack A to lower the temperature of stack A, in process B4, gas in treatment tank B is blown toward stack B to lower the temperature of stack B, and in process C4, gas in treatment tank C is blown toward stack C to lower the temperature of stack C. Therefore, according to the separator assembly manufacturing method recited in claim 9 and a fuel cell manufacturing method for manufacturing a fuel cell using a separator assembly manufactured in accordance with the separator assembly manufacturing method, the amount of temperature drop in each portion of the stack can be made uniform and the thermal shrinkage state of each portion can be made similar, thereby making it possible to suitably avoid unintended deformation or cracks in the separator assembly. [Brief description of the drawings]

[0036] [Figure 1] FIG. 1 is a configuration diagram showing the configuration of a separator manufacturing apparatus 1. [Diagram 2]2 is a cross-sectional view of a fuel cell 50. FIG. [Diagram 3] FIG. [Figure 4] FIG. [Diagram 5] FIG. [Figure 6] FIG. [Figure 7] FIG. [Figure 8] FIG. 2 is a plan view of a carbon sheet Sc. [Figure 9] FIG. 4 is a cross-sectional view of laminates 55a and 55b. [Figure 10] 10 is an explanatory diagram for explaining the degree of vacuum in the treatment tank 10, the temperature of the laminate 55a, and the pressing force applied to the laminate 55a during the production of the separator assembly 51. FIG. [Figure 11] FIG. 11 is a cross-sectional view of a laminate 55a before the start of heating and pressing treatment. [Figure 12] FIG. 11 is a cross-sectional view of a laminate 55a after completion of the heating and pressing process. [Figure 13] 2 is a cross-sectional view of a separator assembly 51. FIG. [Figure 14] 1 is an explanatory diagram for explaining the relationship between the distance from the surface of a plate 71 in a separator assembly 51 and the composition ratio of iron, carbon, nickel, and chromium. FIG. [Figure 15] 7 is an explanatory diagram for explaining the relationship between the distance from the surface of a separator assembly made of a metal block of the same material as plate 71 and the composition ratio of iron, carbon, nickel and chromium. FIG. [Figure 16] FIG. 11 is an explanatory diagram for explaining the relationship between the distance from the surface of a plate 71 and the composition ratio of iron, carbon, nickel, and chromium in a separator assembly manufactured by reducing the upper limit of the pressing force applied to a stack 55b to a pressing force P1. [Figure 17] 16 is an explanatory diagram for explaining the relationship between the distance from the surface of the separator assembly in which the surface of the metal block in the example shown in FIG. 15 is carbon-coated, and the composition ratio of iron, carbon, nickel, and chromium. FIG. [Figure 18] FIG. 2 is a cross-sectional view of a separator assembly 51A. [Figure 19] FIG. 4 is a cross-sectional view of a separator assembly 51B. [Figure 20] FIG. 2 is a plan view of the conductive packing P. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0037] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of a separator assembly manufacturing method, a fuel cell manufacturing method, and a separator assembly manufacturing apparatus will be described with reference to the accompanying drawings.

[0038] First, the configuration of a separator manufacturing apparatus 1 will be described with reference to the accompanying drawings.

[0039] The separator manufacturing apparatus 1 shown in FIG. 1 is an example of a "separator assembly manufacturing apparatus" and is configured to be capable of manufacturing a separator assembly 51 (see FIG. 2) and the like in accordance with a "separator assembly manufacturing method" described below.

[0040] In this case, the separator assembly 51 is an example of a "separator assembly" and, together with the separators 52a, 52b and the MEAs 53, 53, etc., constitutes a fuel cell 50, which is an example of a "fuel cell", as shown in Fig. 2. Specifically, the separator assembly 51 is integrally formed with a separator 61a (an example of "separator A") through which hydrogen gas, which is an example of "power generating gas A", is passed, a separator 61b (an example of "separator B") through which air (atmosphere), which is an example of "power generating gas B", is passed, and a separator 62 (an example of "separator C") through which a cooling fluid (air (atmosphere) as an example) for cooling both separators 61a, 61b is passed.

[0041] Separators 61a and 61b are formed by integrating plates 71 to 73 with a carburized portion 71c formed on one surface of plate 71, and separator 62 is formed by integrating plates 81 and 82. In separator assembly 51 of this example, the plates 71 to 73, 81, and 82 correspond to "plurality of plates" and are formed into a rectangular shape in plan view from thin flat plates of austenitic stainless steel (e.g., SUS316L, SUS316, SUS304).

[0042] Plate 71 is an example of a "metal plate A1, B1" and, as shown in Figure 3, has a plurality of through holes 71a formed therein that form flow paths for passing hydrogen gas as "power generation gas A", air as "power generation gas B", and air as "cooling fluid", as well as a plurality of slits 71b formed therein that are an example of "slits A, B penetrating in the plate thickness direction".

[0043] 4, similar to the through holes 71a in the plate 71, a plurality of through holes 72a are formed that form flow paths for hydrogen gas as the "power generation gas A", air as the "power generation gas B", and air as the "cooling fluid", and a plurality of through holes 72b are formed to communicate the ends of adjacent slits 71b in the plate 71 and between the through holes 71a and the slits 71b. Note that in this plate 72, blocking portions 72c that overlap the slits 71b of the plate 71 when the plate 72 is placed on top of the plate 71 correspond to "blocking portions A and B that block one of the slits A and B in the plate thickness direction".

[0044] In these separators 61a, 61b, grooves H61 (see FIG. 13), which are an example of "grooves A, B through which power-generating gases A, B pass", are formed by slits 71b of plate 71 and closed portions 72c of plate 72. Plate 73, as shown in FIG. 5, is formed with a plurality of through holes 73a that form flow paths for hydrogen gas as "power-generating gas A", air as "power-generating gas B", and air as a "cooling fluid", similar to the through holes 71a, 72a in plates 71, 72.

[0045] Plate 81 is an example of a "metal plate C1", and as shown in Figure 6, similar to the through holes 71a-73a in plates 71-73, plate 81 has a plurality of through holes 81a that form flow paths for hydrogen gas as "power generation gas A", air as "power generation gas B", and air as "cooling fluid", as well as a plurality of slits 81b that are an example of "slits C that penetrate in the plate thickness direction".

[0046] The plate 82 is an example of a "metal plate C2", and as shown in FIG. 7, a plurality of through holes 82a are formed in the plate 82 to form flow paths for hydrogen gas as a "power generation gas", air as a "power generation gas", and air as a "cooling fluid", similarly to the through holes 71a-73a, 81a in the plates 71-73, 81, and a plurality of through holes 82b are formed to connect ends of adjacent slits 81b of the plate 81 and to connect the through holes 81a and the slits 81b. In the plate 82, as described above, the blocking portion 82c that overlaps with the slit 81b of the plate 81 in a state where the plate 82 is overlapped on the plate 81 corresponds to the "blocking portion C that blocks one side of the slit C in the plate thickness direction". In the separator 62, the slit 81b of the plate 81 and the blocking portion 82c of the plate 82 form a groove portion (not shown) that is an example of the "groove portion C through which the cooling fluid passes".

[0047] 2, the separators 52a, 52b which constitute the fuel cell 50 in combination with the separator assembly 51 are configured by integrating a plate 91 having a carburized portion 91c formed on one surface thereof similar to the plate 71 in the separators 61a, 61b, a plate 92 configured similar to the plate 72 in the separators 61a, 61b, and a plate 93 configured similar to the plate 73 in the separators 61a, 61b. In the separators 61a, 61b of this example, each of the plates 91 to 93 is formed in a rectangular shape in a plan view from a thin flat plate of austenitic stainless steel (e.g., SUS316L, SUS316, SUS304).

[0048] The MEA 53 is a membrane electrode assembly for a fuel cell that is formed by stacking an electrode catalyst, an electrolyte membrane, a gas diffusion layer, etc., and is formed in a rectangular shape in a plan view, similar to the separators 61a, 61b, 62, 52a, and 52b. Note that the specific configuration of the "MEA (membrane electrode assembly for a fuel cell)" in the "fuel cell" is publicly known, so a detailed description will be omitted.

[0049] 1, the separator manufacturing apparatus 1 is configured to include a treatment tank 10, a vacuum pump 11, a control valve 12, a nitrogen tank 13, a heater 14, a blower 15, a pressurizing mechanism 16, an operation unit 17, a display unit 18, a control unit 19, and a storage unit 20. The treatment tank 10 is an example of a "treatment tank", and is configured as a pressure-resistant and heat-resistant container capable of accommodating a treatment target such as a laminate 55b described below, the heater 14, the pressurizing mechanism 16, and the like.

[0050] The vacuum pump 11 increases the degree of vacuum (vacuum pressure) in the treatment tank 10 by exhausting the air in the treatment tank 10 under the control of the control unit 19. The control valve 12 is disposed in an introduction pipe that introduces nitrogen from the nitrogen tank 13 to the treatment tank 10, and reduces the degree of vacuum (vacuum pressure) in the treatment tank 10 by introducing nitrogen into the treatment tank 10 under the control of the control unit 19. The nitrogen tank 13 contains industrial nitrogen that has been dehumidified so that the absolute humidity is sufficiently low. In the separator manufacturing apparatus 1 of this example, the vacuum pump 11, the control valve 12, and the nitrogen tank 13 work together to form a "vacuum adjustment unit."

[0051] The heater 14, in cooperation with the blower 15, constitutes a "temperature adjustment unit" and is housed in the treatment tank 10 as described above, and heats (increases the temperature of) the laminate 55b described below housed in the treatment tank 10 under the control of the control unit 19. The blower 15, under the control of the control unit 19, blows nitrogen introduced from the nitrogen tank 13 into the treatment tank 10 toward the laminate 55b on which a diffusion bonding process described below has been completed, thereby uniformly lowering the temperature of the entire laminate 55b.

[0052] Pressurizing mechanism 16 is an example of a "pressurizing unit" and includes an actuator 16a that pressurizes stack 55b accommodated in treatment tank 10 in the thickness direction of each of plates 71-73, 81, 82. Operation unit 17 includes operation switches for setting the manufacturing conditions for separator assembly 51, etc., by separator manufacturing apparatus 1 and for instructing start and interruption of processing, and outputs operation signals in response to switch operations to control unit 19. Display unit 18 displays a display screen for setting the operating conditions for separator manufacturing apparatus 1 and a display screen showing the operating state of separator manufacturing apparatus 1.

[0053] The control unit 19 performs overall control of the separator manufacturing apparatus 1. The control unit 19 is an example of a "control unit" and controls the vacuum pump 11 to exhaust the air from the treatment tank 10, controls the heater 14 to increase the temperature of the laminate 55b, and controls the pressurizing mechanism 16 (actuator 16a) to pressurize the laminate 55b. The control unit 19 also controls the control valve 12 to introduce nitrogen into the treatment tank 10, and controls the blower 15 to blow nitrogen toward the laminate 55b. The memory unit 20 stores an operation program for the control unit 19, operation conditions of the separator manufacturing apparatus 1, and the like.

[0054] Next, an example of the "separator assembly manufacturing method" and the "fuel cell manufacturing method" will be described with reference to the attached drawings.

[0055] When manufacturing the separator assembly 51 using the separator manufacturing apparatus 1, first, the aforementioned plates and the like are stacked to produce the laminate 55b shown in Fig. 9. Specifically, the aforementioned plates 71-73, 81, and 82 and the carbon sheet Sc shown in Fig. 8 are prepared. In this case, the carbon sheet Sc is formed into a rectangular shape in plan view similar to the plates 71-73, 81, and 82 by cutting a graphite sheet (for example, "PERMA-FOIL (registered trademark)" manufactured by Toyo Tanso Co., Ltd.) having a thickness in the range of 0.1 mm to 2.0 mm.

[0056] Next, as shown in the figure, carbon sheet Sc, plate 71, plate 72, plate 73, plate 82, plate 81, plate 73, plate 72, plate 71, and carbon sheet Sc are stacked in this order. This completes stack 55b. In this case, in the configuration example of stack 55b, the lower plates 71-73 and plates 81 and 82 in the figure and the upper plates 71-73 in the figure correspond to the "plurality of plates."

[0057] Next, a door (not shown) of the treatment tank 10 is opened, and the laminate 55b is placed in the treatment tank 10 and set in the pressurizing mechanism 16 as shown in Fig. 1, and then the door is closed. It is assumed that the treatment conditions for the following treatments performed in the separator manufacturing apparatus 1 are preset and the treatment condition data are stored in the memory unit 20.

[0058] Next, the operator operates the operation unit 17 to instruct the start of the process. In response to this, the control unit 19 executes the following processes in this order according to the above process condition data: "first process" for increasing the degree of vacuum in the process tank 10; "second process" for increasing the temperature of the laminate 55b to a "predetermined first temperature" to reduce and remove the passivation film of each of the plates 71-73, 81, 82; "third process" for increasing the temperature of the laminate 55b to a "predetermined second temperature" in a state in which the laminate 55b is pressurized with a "predetermined pressure" to diffusion bond each of the plates 71-73, 81, 82; and "fourth process" for decreasing the temperature of the laminate 55b and decreasing the degree of vacuum in the process tank 10 to return it to atmospheric pressure.

[0059] 10, at time t0 when an instruction to start processing is given by operating operation unit 17, control unit 19 controls actuator 16a to pressurize stack 55b in the thickness direction of each plate with a pressing force P1 that does not cause any misalignment between the plates of stack 55b. Next, control unit 19 starts the "first processing" at time t1 when the pressure applied by pressurizing mechanism 16 reaches pressing force P1, and controls vacuum pump 11 to exhaust air from within processing tank 10 (to draw a vacuum), thereby increasing the degree of vacuum within processing tank 10 from atmospheric vacuum V0 to a preset vacuum V1.

[0060] Next, the control unit 19 starts the "second process" at time t2 when the degree of vacuum V1 is reached in the process tank 10, and controls the heater 14 to raise the temperature of the stack 55b to the "predetermined first temperature". In this case, the plates 71-73, 81, and 82 constituting the stack 55a in the stack 55b have a passivation state (oxide film) on their surfaces, and the presence of this passivation state may be a factor in inhibiting diffusion bonding, reducing the bonding strength of the plates 71-73, 81, and 82, or making it difficult to form a suitable carburized layer on the surface of the plate 71, which will be described later. In addition, in a state in which the plates 71-73, 81, and 82 have a passivation state (oxide film), even if they can be bonded with a certain degree of bonding strength, the electrical resistance value is high due to the presence of the passivation state, and the electrical characteristics of the separator assembly 51 to be manufactured may be degraded.

[0061] Here, the applicant has confirmed that the passivation occurring in the austenitic stainless steel (for example, SUS316L) used in this example can be suitably reduced and removed to a degree that does not cause the above-mentioned manufacturing problems or significant deterioration of electrical characteristics by maintaining a heated state at a temperature in the range of 680°C to 800°C for a certain period of time. Therefore, the control unit 19 heats the stack 55b to a temperature Tb (an example of the "predetermined first temperature") within the above-mentioned temperature range by the heater 14, and maintains the state for a period of time T1 from a time t3 when the temperature of the stack 55b reaches the temperature Tb, thereby sufficiently reducing and removing the passivation film of each of the plates 71 to 73, 81, and 82.

[0062] Moreover, as an example, at time t2 when the above-mentioned "second process" is started, the control unit 19 controls the actuator 16a to pressurize the laminate 55b in the thickness direction of each plate with a pressing force P2 (an example of a "predetermined pressing force") suitable for the diffusion bonding process described below.

[0063] On the other hand, at time t4 when the above-mentioned time T1 has elapsed, the control unit 19 starts the above-mentioned "third process" and controls the heater 14 to raise the temperature of the laminate 55b to a temperature Tc (an example of a "predefined second temperature higher than the first temperature") suitable for the diffusion bonding process while maintaining the state in which the pressure mechanism 16 presses the laminate 55b. The control unit 19 also maintains this state for time T2 from time t5 when the temperature of the laminate 55b reaches temperature Tc. As a result, the plates 71 to 73, 81, and 82 are diffusion bonded together and integrated as if they were a single metal block (diffusion bonding process).

[0064] In this case, in this example, the laminate 55b, which is a laminate of the plates 71 to 73, 81, and 82, is treated in the treatment tank 10, with the carbon sheets Sc laminated on one side (the surface of the lower plate 71 shown in FIG. 9: the lower side) and the other side (the surface of the upper plate 71 shown in FIG. 9: the upper side) of the laminate 55a. Therefore, in the above-mentioned diffusion bonding process, the carbon sheet Sc laminated on the laminate 55a is pressed against the laminate 55a (plate 71) with a pressing force P2 in a state in which the temperature of the laminate 55a is raised to the temperature Tc together with the laminate 55a. As a result, the carbon in the carbon sheet Sc is carburized into the plate 71, and the carburized parts 71c (see FIGS. 12 and 13) described later are formed on the surfaces of the plates 71, 71 (both the front and back sides of the laminate 55a).

[0065] Next, at time t6 when the above-mentioned time T2 has elapsed, the control unit 19 starts the above-mentioned "fourth process", controls the heater 14 to stop heating the laminate 55b, controls the blower 15 to start blowing air to lower the temperature of the laminate 55b, controls the vacuum pump 11 to stop exhaust (vacuum drawing), and controls the control valve 12 to introduce nitrogen from the nitrogen tank 13 into the treatment tank 10 to lower the degree of vacuum in the treatment tank 10.

[0066] In this case, unlike the manufacturing method of this example, when air (atmosphere) is introduced into the treatment tank 10 instead of nitrogen to reduce the degree of vacuum in the treatment tank 10, the oxygen contained in the introduced air may come into contact with the high-temperature laminate 55b, oxidizing the side surface of the laminate 55b and the inner wall surface of the flow path formed by the through holes 71a-73a, 81a, 82a, etc., and may form an oxide film on these parts. Therefore, in the "fourth treatment", it is preferable to introduce "a stable gas (nitrogen in this example) that has a low oxygen content and does not adversely affect the surrounding environment" into the treatment tank 10 so that a large amount of oxygen does not come into contact with the laminate 55b during the temperature decrease.

[0067] Furthermore, as an example, at time t6 when the above-mentioned "fourth process" is started, the control unit 19 controls the actuator 16a to gradually reduce the pressing force applied to the laminate 55b. Thereafter, at time t7 when the inside of the processing tank 10 reaches a vacuum degree V0 under atmospheric pressure and the temperature of the laminate 55b has dropped to a sufficiently low temperature Ta (a temperature at which an oxide film is unlikely to form when the laminate 55b comes into contact with oxygen in the air and at which workers will not be burned when handling the laminate 55b), the door of the processing tank 10 is opened and the laminate 55b is taken out. With the above, a series of processes by the separator manufacturing apparatus 1 is completed.

[0068] Next, a process is carried out to remove the carbon sheet Sc remaining on the plates 71, 71 in the laminate 55b that has been removed from the treatment tank 10 after completing the "fourth treatment" (hereinafter, this process is also referred to as the "fifth treatment").

[0069] Specifically, in stack 55b when stacked in treatment tank 10 at the start of a series of treatments by separator manufacturing apparatus 1 as described above, carbon sheet Sc is superimposed on stack 55a so as to be in close contact with one surface of plate 71, as shown in Fig. 11. By treating stack 55b in treatment tank 10 of separator manufacturing apparatus 1 as described above, plates 71-73, 81, 82 constituting stack 55a are diffusion-bonded and integrated as described above, and carbon in carbon sheet Sc carburizes the surface of stack 55a (plate 71), forming carburized portion 71c on the surface side of stack 55a (plate 71), as shown in Fig. 12.

[0070] Furthermore, the carbon sheet Sc remaining on the laminate 55a (plate 71) without being carburized (hereinafter, the remaining carbon sheet Sc is also referred to as the carbon sheet Sca in order to distinguish it from the carbon sheet Sc before the start of the treatment) is hardened by the pressure applied by the pressurizing mechanism 16 and the heating by the heater 14, and is in a very brittle state. Furthermore, when the carbon sheet Sca remains on the laminate 55a (plate 71), the groove portion H61 formed by the slit 71b of the plate 71 and the blocking portion 72c of the plate 72 is in a state of being blocked by the carbon sheet Sca. Therefore, when the fuel cell 50 is manufactured using the laminate 55b in such a state, hydrogen gas or air as the "power generation gas" that is passed through the groove portion H61 does not come into contact with the MEA 53, that is, power generation is inhibited.

[0071] Therefore, by performing the "fifth process", the carbon sheet Sca is removed from the laminate 55b to expose the groove H61, as shown in FIG. 13. At this time, the carbon sheet Sca is removed by performing a blasting process in which grinding media is sprayed onto the remaining surface of the carbon sheet Sca, a polishing process in which the remaining surface of the carbon sheet Sca is polished using a paste or sheet-like abrasive, and a peeling process in which the carbon sheet Sca is peeled off using a scraper or the like. When removing unnecessary carbon sheet Sca, it is preferable to adopt a method that can process the laminate 55b without excessively increasing the temperature, and to avoid the occurrence of cracks due to partial temperature increase. With the above, the "fifth process" is completed, and the separator assembly 51 is completed.

[0072] The separators 52a, 52b used in the manufacture of the fuel cell 50 can be manufactured by carrying out the same series of processes from the "first process" to the "fifth process" in the manufacture of the separator assembly 51. In this case, when manufacturing the separators 52a, 52b, instead of the plates 71-73, 81, 82 and the carbon sheet Sc used in the manufacture of the separator assembly 51, a stack (not shown) of the plates 91-93 and the carbon sheet Sc is placed in the treatment tank 10 of the separator manufacturing apparatus 1 and a series of processes from the "first process" to the "fourth process" are carried out, and then the stack is removed from the treatment tank 10 and subjected to the "fifth process".

[0073] On the other hand, when manufacturing the fuel cell 50, the separator assembly 51 manufactured as described above, the separators 52a and 52b, and the two MEAs 53 manufactured in advance are prepared. The separator assembly 51, the separators 52a and 52b, and the two MEAs 53 are the minimum elements necessary to configure the fuel cell 50, and when actually manufacturing the "fuel cell", in addition to these elements, various components according to the use of the "fuel cell" are prepared and integrated. Next, as shown in FIG. 2, the separator 52a, the MEA 53, the separator assembly 51, the MEA 53, and the separator 52b are stacked together, and as an example, the separator assembly 51, the separators 52a and 52b, and the MEAs 53 and 53 are positioned and fixed with bolts / nuts (not shown) while sandwiched between a pair of pressing plates (not shown). This completes the fuel cell 50. Note that a power generation module (power generation section in a fuel cell) manufactured using this fuel cell 50 may incorporate current collector plates, heat sinks, and the like (not shown) depending on its specifications, but detailed explanation of these elements will be omitted.

[0074] In this case, in the separator assembly 51 manufactured according to the above manufacturing method, the plates 71-73, 81, 82, which are the constituent materials, have sufficient hardness and toughness, so that they are less likely to break when subjected to vibration or impact compared to carbon molded products. In addition, in this separator assembly 51, the plates 71-73, 81, 82 are bonded with sufficient bonding strength by diffusion bonding, and the plates 71-73, 81, 82 are integrated as if they were composed of a single metal block. Therefore, even if the separator assembly 51 is manufactured using plates 71-73, 81, 82 that are relatively thin, the rigidity of the separator assembly 51 as a whole can be sufficiently high. The same applies to the separators 52a and 52b in this respect.

[0075] Furthermore, in the separator assembly 51 and the separators 52a, 52b manufactured according to the above manufacturing method, the passivation film is preferably removed in the "second treatment", so that not only can the plates be preferably bonded in the diffusion bonding in the "third treatment", but also, since there is no passivation in the separator assembly 51 and the separators 52a, 52b as a finished product, their electrical resistance is small, so that a product with sufficiently good electrical properties can be provided.

[0076] Furthermore, in the separator assembly 51 and separators 52a, 52b manufactured according to the above manufacturing method, in the "third treatment", the carbon sheet Sc is pressed against the plates 71, 91 in a state where the entire stack 55b is heated to temperature Tc, so that the carbon of the carbon sheet Sc penetrates the plates 71, 91, thereby forming carburized portions 71c, 91c on the surfaces of the plates 71, 91. Specifically, as shown in Fig. 14, in the separator assembly 51 manufactured according to the above manufacturing method, the presence of the carburized portion 71c makes the carbon composition ratio sufficiently high from the surface of the plate 71 to a sufficient depth. In addition, in this figure and in Figures 15 to 17 referred to later, for each depth [μm] from the surface of the object, the "proportion occupied by carbon (C)" is indicated by a solid line L1, the "proportion occupied by iron (Fe)" is indicated by a dashed line L2, the "proportion occupied by nickel (Ni)" is indicated by a dotted line L3, and the "proportion occupied by chromium (Cr)" is indicated by a roughly dashed line L4.

[0077] Therefore, in this separator assembly 51, the electrical resistance of the surface portion of the plate 71 in contact with the MEA 53 when assembled into the fuel cell 50 is sufficiently low, making it possible to provide a product with sufficiently high electrical properties. Also, the carburized portion 71c present on the surface portion of the separator assembly 51 (plate 71) functions as a protective layer, making it difficult for oxidation of iron, chromium, nickel, and the like to proceed on the surface portion.

[0078] In contrast, for example, a "separator assembly" manufactured by forming "grooves" by cutting or etching a metal plate (SUS316L plate material) of the same material as the plates 71-73, 81, and 82 used in manufacturing the separator assembly 51, and bonding the plate with a conductive adhesive, that is, a metallic "separator assembly" manufactured without carrying out the above-mentioned "first treatment" to "fifth treatment", has sufficient hardness, rigidity, and toughness like the separator assembly 51. However, since the above-mentioned "second treatment" is not carried out in the manufacturing process, a passivation state (a chromium oxide film) is generated on the surface of the metal plate. Therefore, the presence of this passivation state increases the electrical resistance of the surface of the "separator assembly", making it difficult to provide a product with good electrical properties. Also, unlike the separator assembly 51 described above, as shown in FIG. 15, although a very small amount of naturally contained carbon is present on its surface, the amount is so small that the reduction in electrical resistance due to the presence of carbon and the effect of inhibiting the oxidation of iron, chromium, nickel, and the like cannot be expected.

[0079] In the manufacturing method of the separator assembly 51 described above, the "third process" is performed in a state where the laminate 55b is pressurized to the pressing force P2 to diffusion-bond the plates 71-73, 81, and 82. However, the applicant has confirmed that the plates 71-73, 81, and 82 can be suitably bonded even when the "third process" diffusion bonding process is performed in a state where the laminate 55b is pressurized with a weak pressing force equivalent to the pressing force P1 instead of such a manufacturing method. Also, as shown in FIG. 16, even when the pressing force of the laminate 55b during the "third process" is weakened, the carbon of the carbon sheet Sc can be penetrated into the plate 71 to form the carburized portion 71c to a sufficient depth. Therefore, the separator assembly manufactured by such a manufacturing method can provide a product with sufficiently high electrical properties like the separator assembly 51, and can suppress the progress of oxidation of iron, chromium, nickel, and the like in the surface area.

[0080] On the other hand, when the surface of the separator assembly described with reference to FIG. 15 is carbon-coated (for example, a process for forming a carbon coating by sputtering), the ratio of carbon can be increased to a sufficient depth on the surface side, as shown in FIG. 17. This allows the electrical resistance of the surface portion of the separator assembly, i.e., the carbon coating portion, to be sufficiently reduced, and the presence of a protective layer formed by the carbon coating allows the progress of oxidation of iron, chromium, nickel, and the like to be sufficiently suppressed. However, in a separator assembly manufactured by such a manufacturing method, the metal mass existing under the carbon coating is the same as that of the separator assembly described with reference to FIG. 15, and the surface of this metal mass is in a passive state (a layer of chromium oxide) with high electrical resistance. This makes it difficult to provide a product with good electrical properties, even though the resistance of the surface portion is low.

[0081] In this manner, in the separator assembly manufacturing method, a laminate 55a (in this example, a laminate 55b in which carbon sheets Sc are laminated on both sides in the thickness direction of the laminate 55a) is placed in a treatment tank 10 and the degree of vacuum in the treatment tank 10 is increased as a "first treatment" and a temperature of the laminate 55b is increased to a predetermined temperature Tb to perform a pretreatment. a "second process" for reducing and removing the passivation film on the plates 71-73, 81, 82; a "third process" for increasing the temperature of the laminate 55b to a predetermined temperature Tc higher than temperature Tb while pressurizing the laminate 55b with a predetermined pressing force P2, thereby diffusion bonding the plates 71-73, 81, 82; and a "fourth process" for decreasing the temperature of the laminate 55b and decreasing the degree of vacuum in the treatment tank 10, in that order, to produce a separator assembly 51 integrated with the separators 61a, 61b having groove portions H61 formed by slits 71b and blocking portions 72c for passing a "power generation gas", and the separator 62 having groove portions C formed by slits 81b and blocking portions 82c for passing a "cooling fluid".

[0082] In addition, in this fuel cell manufacturing method, a fuel cell 50 is manufactured by sandwiching an MEA 53 between a separator assembly 51 and separators 52a, 52b manufactured by the above-mentioned separator assembly manufacturing method, and integrating the separator assembly 51, the separators 52a, 52b, and the MEA 53. The separator manufacturing apparatus 1 further includes a treatment tank 10 capable of accommodating the laminate 55b, a vacuum pump 11, a control valve 12 and a nitrogen tank 13 for adjusting the degree of vacuum within the treatment tank 10, a heater 14 and a blower 15 for adjusting the temperature of the laminate 55b accommodated within the treatment tank 10, a pressurizing mechanism 16 for pressurizing the laminate 55b accommodated within the treatment tank 10 in the thickness direction, and a control unit 19 for controlling the operation of the vacuum pump 11, the control valve 12, the heater 14, the blower 15 and the pressurizing mechanism 16 (actuator 16a), and the control unit 19 performs the above-mentioned "first process", "second process", "third process" and "fourth process" in this order to manufacture the separator assembly 51.

[0083] Therefore, according to the separator assembly manufacturing method, fuel cell manufacturing method, and separator manufacturing apparatus 1, a separator assembly 51 having sufficiently high hardness, rigidity, and toughness can be manufactured by using a metal plate as a material, compared with a carbon separator manufactured by a molding method using a mixture of a carbon resin material formed by applying a thermosetting resin material to the surface of carbon powder to form a coating layer, and a liquid such as water, and kneading the mixture as a molding material. This makes it possible to provide a separator assembly 51 and a fuel cell 50 that are less likely to be damaged due to vibration or impact. In addition, since it is not necessary to make the thickness of each part excessively thick in order to ensure the physical strength of the separator assembly 51, the separator assembly 51 and the fuel cell 50 can be sufficiently miniaturized. In addition, since there is no need to design the shape taking into account demolding (removal from the mold after molding is completed), the degree of freedom in design is sufficiently high, and the separator assembly 51 and the fuel cell 50 can be manufactured in any shape according to the required power generation capacity and use. Furthermore, by carrying out a series of processes from the "first process" to the "fourth process", it is possible to form, within the thickness of the separator assembly 51, grooves (sealed flow paths for passing a cooling fluid) consisting of the slits 81b of the plate 81 and the closed parts of the plate 82, together with the grooves H61 for passing the "power generation gas". This eliminates the need for a process for forming and integrating a plurality of members to form a sealed flow path, and as a result, it is possible to sufficiently reduce the manufacturing cost of the separator assembly 51.

[0084] In addition, in this separator assembly manufacturing method, nitrogen is introduced from the nitrogen tank 13 into the treatment tank 10 in the "fourth treatment" to reduce the degree of vacuum in the treatment tank 10. Therefore, in this separator assembly manufacturing method and fuel cell manufacturing method, unlike a manufacturing method in which air (atmosphere) is introduced into the treatment tank 10 to reduce the degree of vacuum, the amount of oxygen that comes into contact with the laminate 55b heated to a high temperature in the "third treatment" can be sufficiently reduced, and a situation in which a passivation film is formed on the surface of the laminate 55b due to oxidation can be suitably avoided. In addition, since "nitrogen" is relatively inexpensive, has low danger at high temperatures, and is harmless even if released into the atmosphere when the door of the treatment tank 10 is opened after the treatment is completed, it is possible to avoid a rise in the manufacturing cost of the separator assembly 51, an accident during manufacturing, and environmental destruction.

[0085] Furthermore, in this separator assembly manufacturing method, in the fourth treatment, the gas in the treatment tank 10 is blown by the blower 15 toward the stack 55b to lower the temperature of the stack 55b. Therefore, according to this separator assembly manufacturing method and fuel cell manufacturing method, the amount of temperature drop in each part of the stack 55b can be made uniform and the thermal contraction state of each part can be made similar, so that unintended deformation or cracks in the separator assembly 51 can be preferably avoided.

[0086] The specific contents of the "separator assembly manufacturing method" and "fuel cell manufacturing method" and the configuration of the "separator assembly manufacturing apparatus" are not limited to the above-mentioned exemplary contents and configurations.

[0087] For example, the configuration and method for manufacturing the separator assembly 51 in which three separators 61a, 61b, and 62 are integrated by processing the laminate 55b in which two sets of plates 71-73, plates 81 and 82, and two carbon sheets Sc are stacked in the processing tank 10 has been described as an example, but a manufacturing method can also be adopted in which the separator 61a and the separator assembly 60 in which the separator 61b and the separator 62 are integrated are separately manufactured, and then the separator assembly 51A (another example of a "separator assembly") shown in Fig. 18 is manufactured by sandwiching a conductive packing P between the separators 61a, 61b, and 62 and integrating them. Also, a manufacturing method can be adopted in which the separator assembly 51B (yet another example of a "separator assembly") shown in Fig. 19 is manufactured by separately manufacturing the separators 61a, 61b, and 62 and then integrating them by sandwiching a conductive packing P between the separators 61a, 61b, and 62.

[0088] The manufacturing method of the separator 61a and the separator assembly 60 constituting the separator assembly 51A, and the manufacturing method of each of the separators 61a, 61b, and 62 constituting the separator assembly 51B are the same as the manufacturing method of the separator assembly 51 described above, so detailed description will be omitted. Also, the plates 71 to 73 and plates 81 and 82 constituting the separator assembly 51A and 51B are the same as the plates 71 to 73 and plates 81 and 82 constituting the separator assembly 51 described above, so the same reference numerals will be used and duplicated description will be omitted. Also, the conductive packing P is an example of a "sheet-like member having conductivity and being elastically deformable", and is composed of a sheet body formed of an elastic resin material having conductivity, heat resistance, and chemical resistance. As shown in FIG. 20, the conductive packing P has through holes Pa formed in accordance with the formation positions of the through holes 71a to 73a, 8a, and 82a in the plates 71 to 73 and plates 81 and 82.

[0089] In this case, in the manufacturing method of separator assembly 51A, plates 71 to 73 constituting separator 61a correspond to "multiple first plate bodies", a stack of these plates 71 to 73 corresponds to a "first stack", and treatment tank 10 is used as a "first treatment tank". A series of treatments, namely "treatment 1A" which is the same as the aforementioned "first treatment", "treatment 2A" which is the same as the "second treatment", "treatment 3A" which is the same as the "third treatment", and "treatment 4A" which is the same as the "fourth treatment", are carried out in this order to produce separator 61a, which is an example of "separator A".

[0090] In addition, in the manufacturing method of separator assembly 51A, plates 71-73, 81, and 82 constituting separator assembly 60 correspond to "multiple second plate bodies", a stack of these plates 71-73, 81, and 82 corresponds to a "second stack", and treatment tank 10 serves as a "second treatment tank". A series of treatments, namely "treatment 1B", which is the same as the aforementioned "first treatment", "treatment 2B", which is the same as the "second treatment", "treatment 3B", which is the same as the "third treatment", and "treatment 4B", which is the same as the "fourth treatment", are carried out in this order to produce separator assembly 60, which is an example of an "intermediate body".

[0091] In addition, the "first treatment tank" used when producing "separator A" and the "second treatment tank" used when producing the "intermediate" are not limited to using the same treatment tank (treatment tank 10) as in the above example, and a series of processes can be performed using separate "treatment tanks" as the "first treatment tank" and the "second treatment tank."

[0092] In addition, in the manufacturing method of separator assembly 51B, plates 71 to 73 constituting separator 61a correspond to "multiple plate bodies A", a stack of these plates 71 to 73 corresponds to "stack A", and treatment tank 10 is used as "treatment tank A". Separator 61a, which is an example of "separator A", is produced by performing a series of processes in this order: "Process A1", which is the same as the aforementioned "first process", "Process A2", which is the same as the "second process", "Process A3", which is the same as the "third process", and "Process A4", which is the same as the "fourth process".

[0093] In addition, in the manufacturing method of separator assembly 51B, plates 71 to 73 constituting separator 61b correspond to "multiple plate bodies B", a stack of these plates 71 to 73 corresponds to "stack B", and treatment tank 10 is used as "treatment tank B". A series of processes, namely "treatment B1", which is the same as the aforementioned "first treatment", "treatment B2", which is the same as the "second treatment", "treatment B3", which is the same as the "third treatment", and "treatment B4", which is the same as the "fourth treatment", are carried out in this order to produce separator 61b, which is an example of "separator B".

[0094] In addition, in the manufacturing method of separator assembly 51B, plates 81, 82 constituting separator 62 correspond to "multiple plate bodies C", a stack of these plates 81, 82 corresponds to "stack C", and treatment tank 10 is used as "treatment tank C", and a series of processes, namely "process C1", which is similar to the aforementioned "first process", "process C2", which is similar to the "second process", "process C3", which is similar to the "third process", and "process C4", which is similar to the "fourth process", are carried out in this order to produce separator 62, which is an example of "separator C".

[0095] In addition, the "treatment tank A" used in manufacturing "separator A," the "treatment tank B" used in manufacturing "separator B," and the "treatment tank C" used in manufacturing "separator C" are not limited to using the same treatment tank (treatment tank 10) as in the above example, and a series of processes can be performed using separate "treatment tanks" as "treatment tank A," "treatment tank B," and "treatment tank C."

[0096] This separator assembly 51A, and the method for manufacturing a fuel cell 50 using the separator assembly 51A, as well as the separator assembly 51B, and the method for manufacturing a fuel cell 50 using the separator assembly 51B, can achieve effects similar to those of the above-mentioned method for manufacturing the separator assembly 51, and the method for manufacturing the fuel cell 50 using the separator assembly 51. [Explanation of symbols]

[0097] 1. Separator assembly manufacturing equipment 10 Treatment tank 11 Vacuum Pump 12 Control valve 13 Nitrogen Tank 14 Heater 15 Blower 16 Pressurizing mechanism 16a Actuator 17 Control section 18 Display 19 Control section 20 Memory section 50 Fuel Cell 51, 51A, 51B, 60 Separator assembly 52a, 52b, 61a, 61b, 62 Separator 53 MEA 55a, 55b Laminate 71~73,81,82,91~93 Plates 71a~73a,81a,82a,Pa through hole 71b,81b Slit 71c,91c Carburized part 72b,82b through hole 72c,82c Occlusion H61 Groove P Conductive packing P0,P1 Pressing force Sc, Sca carbon sheet Ta~Tc temperature V0,V1 Vacuum degree

Claims

1. A separator assembly manufacturing method for manufacturing a separator assembly in which a separator A having grooves A for passing a generating gas A, a separator B having grooves B for passing a generating gas B to be reacted with the generating gas A, and a separator C having grooves C for passing a cooling fluid and cooling at least one of the separator A and the separator B are integrated together, the method comprising the steps of: A laminate is placed in a treatment tank, the laminate being formed by stacking a plurality of plates in the thickness direction, the plurality of plates including at least a metal plate A1 having a slit A penetrating therethrough in the thickness direction, a metal plate A2 having a blocking portion A blocking one end of the slit A in the thickness direction, a metal plate B1 having a slit B penetrating therethrough in the thickness direction, a metal plate B2 having a blocking portion B blocking one end of the slit B in the thickness direction, a metal plate C1 having a slit C penetrating therethrough in the thickness direction, and a metal plate C2 having a blocking portion C blocking one end of the slit C in the thickness direction; a first process for increasing the degree of vacuum in the processing tank; a second treatment for reducing and removing the passivation film of the plurality of plates by increasing the temperature of the stack to a predetermined first temperature; a third process of increasing a temperature of the laminate to a predefined second temperature higher than the first temperature while pressing the laminate with a predefined pressure, thereby diffusion bonding the plurality of plates; a fourth process for lowering the temperature of the laminate and a fourth process for lowering the degree of vacuum in the treatment tank in this order, thereby producing the separator assembly in which the separator A, in which the groove portion A is defined by the slit A and the blocking portion A, the separator B, in which the groove portion B is defined by the slit B and the blocking portion B, and the separator C, in which the groove portion C is defined by the slit C and the blocking portion C, are integrated together.

2. 2. The method for manufacturing a separator assembly according to claim 1, wherein in the fourth treatment, nitrogen is introduced into the treatment tank to reduce the degree of vacuum within the treatment tank.

3. 2. The method for producing a separator assembly according to claim 1, wherein in the fourth treatment, a gas in the treatment tank is blown toward the laminate to lower the temperature of the laminate.

4. A separator assembly manufacturing method for manufacturing a separator assembly in which a separator A having grooves A for passing a generating gas A, a separator B having grooves B for passing a generating gas B to be reacted with the generating gas A, and a separator C having grooves C for passing a cooling fluid and cooling at least one of the separator A and the separator B are integrated together, the method comprising the steps of: A first laminate is formed by stacking a plurality of first plates, the first plates including at least a metal plate A1 having a slit A penetrating therethrough in a thickness direction and a metal plate A2 having a blocking portion A blocking one end of the slit A in the thickness direction, in the thickness direction of the first plate, in a first treatment tank; A process 1A for increasing the degree of vacuum in the first treatment tank; A process 2A in which a temperature of the first stack is increased to a predetermined first temperature to reduce and remove a passivation film on the first plates; A process 3A in which the temperature of the first laminate is increased to a predetermined second temperature higher than the first temperature while the first laminate is pressed with a predetermined pressure, thereby diffusion bonding the plurality of first plates; and a process 4A for lowering the temperature of the first laminate and lowering the degree of vacuum in the first treatment tank in this order, thereby manufacturing the separator A in which the groove portion A is formed by the slit A and the blocking portion A, A second laminate is formed by stacking a plurality of second plates in the thickness direction, the second laminate including at least a metal plate B1 having a slit B penetrating in the thickness direction, a metal plate B2 having a blocking portion B blocking one end of the slit B in the thickness direction, a metal plate C1 having a slit C penetrating in the thickness direction, and a metal plate C2 having a blocking portion C blocking one end of the slit C in the thickness direction, in the thickness direction, in a second treatment tank; A process 1B for increasing the degree of vacuum in the second processing tank; A process 2B in which the temperature of the second stack is increased to a predetermined third temperature to reduce and remove the passivation film of the plurality of second plates; a process 3B in which the temperature of the second laminate is increased to a predetermined fourth temperature higher than the third temperature while the second laminate is pressed with a predetermined pressure, thereby diffusion bonding the plurality of plates; and a process 4B for reducing the temperature of the second laminate and the degree of vacuum in the second treatment tank, in this order, to manufacture an intermediate body in which the separator B, in which the groove portion B is formed by the slit B and the blocking portion B, and the separator C, in which the groove portion C is formed by the slit C and the blocking portion C, are integrated together; A separator assembly manufacturing method in which a conductive and elastically deformable sheet-like member is sandwiched between the separator A and the intermediate body, and the separator A, the sheet-like member and the intermediate body are integrated to produce the separator assembly.

5. In the process 4A, nitrogen is introduced into the first processing tank to reduce the degree of vacuum in the first processing tank, 5. The method for producing a separator assembly according to claim 4, wherein in said step 4B, nitrogen is introduced into said second treatment tank to reduce the degree of vacuum in said second treatment tank.

6. In the process 4A, the gas in the first process tank is blown toward the first laminate to lower the temperature of the first laminate, 5. The method for producing a separator assembly according to claim 4, wherein in said step 4B, a gas in said second treatment tank is blown toward said second laminate to lower the temperature of said second laminate.

7. A separator assembly manufacturing method for manufacturing a separator assembly in which a separator A having grooves A for passing a generating gas A, a separator B having grooves B for passing a generating gas B to be reacted with the generating gas A, and a separator C having grooves C for passing a cooling fluid and cooling at least one of the separator A and the separator B are integrated together, the method comprising the steps of: A laminate A is formed by stacking a plurality of plates A, each plate A including at least a metal plate A1 having a slit A penetrating therethrough in the thickness direction and a metal plate A2 having a blocking portion A blocking one end of the slit A in the thickness direction, in the thickness direction of the plate A, in a treatment tank A; A process A1 for increasing the degree of vacuum in the processing tank A; A process A2 in which the temperature of the laminate A is increased to a predetermined temperature 1A to reduce and remove the passivation film of the plurality of plates A; a process A3 in which the temperature of the laminate A is increased to a predefined temperature 2A higher than the temperature 1A while the laminate A is pressed with a predefined pressure, thereby diffusion bonding the plurality of plates A; and a process A4 for reducing the temperature of the laminate A and the degree of vacuum in the treatment tank A in this order, thereby manufacturing the separator A in which the groove portion A is formed by the slit A and the blocking portion A, A laminate B is formed by stacking a plurality of plate bodies B, each of which includes at least a metal plate B1 having a slit B penetrating therethrough in the thickness direction and a metal plate B2 having a blocking portion B blocking one end of the slit B in the thickness direction, in the thickness direction of the plate body B, in a treatment tank B; A process B1 for increasing the degree of vacuum in the processing tank B; A process B2 in which the temperature of the laminate B is increased to a predetermined temperature 1B to reduce and remove the passivation film of the plurality of plates B; a process B3 in which the temperature of the laminate B is increased to a predefined temperature 2B higher than the temperature 1B while the laminate B is pressed with a predefined pressure, thereby diffusion bonding the plurality of plates B; and a process B4 for lowering the temperature of the laminate B and lowering the degree of vacuum in the treatment tank B in this order, thereby manufacturing the separator B in which the groove portion B is formed by the slit B and the blocking portion B, A laminate C is formed by stacking a plurality of plates C, each of which includes at least a metal plate C1 having a slit C penetrating therethrough in the thickness direction and a metal plate C2 having a blocking portion C blocking one end of the slit C in the thickness direction, in the thickness direction of the plate C, and the laminate C is placed in a treatment tank C; A process C1 for increasing the degree of vacuum in the processing tank C; A process C2 in which the temperature of the laminate C is increased to a predetermined temperature 1C to reduce and remove the passivation film of the plurality of plates C; a process C3 in which the temperature of the laminate C is increased to a predefined temperature 2C higher than the temperature 1C while the laminate C is pressed with a predefined pressure, thereby diffusion bonding the plurality of plates C; and a process C4 for reducing the temperature of the laminate C and the degree of vacuum in the treatment tank C in this order, thereby manufacturing the separator C in which the groove portion C is formed by the slit C and the blocking portion C; A separator assembly manufacturing method, comprising: sandwiching a first sheet-like member that is conductive and elastically deformable between the separator A and the separator C; and sandwiching a second sheet-like member that is conductive and elastically deformable between the separator B and the separator C; and integrating the separator A, the first sheet-like member, the separator C, the second sheet-like member, and the separator B to manufacture the separator assembly.

8. In the process A4, nitrogen is introduced into the process tank A to reduce the degree of vacuum in the process tank A; In the process B4, nitrogen is introduced into the process tank B to reduce the degree of vacuum in the process tank B, 8. The method for producing a separator assembly according to claim 7, wherein in said step C4, nitrogen is introduced into said treatment vessel C to reduce the degree of vacuum in said treatment vessel C.

9. In the process A4, the gas in the process tank A is blown toward the laminate A to lower the temperature of the laminate A; In the process B4, the gas in the process tank B is blown toward the laminate B to lower the temperature of the laminate B, 8. The method for producing a separator assembly according to claim 7, wherein in said step C4, the gas in said treatment tank C is blown toward said laminate C to lower the temperature of said laminate C.

10. 10. A method for manufacturing a fuel cell, comprising: sandwiching a fuel cell membrane electrode assembly between a plurality of separator assemblies manufactured by the separator assembly manufacturing method according to any one of claims 1 to 9; and integrating the separator assemblies and the fuel cell membrane electrode assembly in a state in which the separator assemblies and the fuel cell membrane electrode assembly are integrated to manufacture a fuel cell.

11. A separator assembly manufacturing apparatus for manufacturing a separator assembly in which a separator A having grooves A for passing a generating gas A, a separator B having grooves B for passing a generating gas B to be reacted with the generating gas A, and a separator C having grooves C for passing a cooling fluid and cooling at least one of the separator A and the separator B are integrated together, the separator assembly comprising: a treatment tank capable of accommodating a stack of a plurality of plate bodies stacked in a thickness direction, the stack including at least a metal plate A1 having a slit A penetrating therethrough in a thickness direction, a metal plate A2 having a blocking portion A blocking one end of the slit A in the thickness direction, a metal plate B1 having a slit B penetrating therethrough in the thickness direction, a metal plate B2 having a blocking portion B blocking one end of the slit B in the thickness direction, a metal plate C1 having a slit C penetrating therethrough in the thickness direction, and a metal plate C2 having a blocking portion C blocking one end of the slit C in the thickness direction; a vacuum adjustment unit for adjusting the degree of vacuum in the treatment tank; a temperature adjusting unit that adjusts the temperature of the laminate contained in the treatment tank; a pressurizing unit that presses the laminate contained in the treatment tank in the plate thickness direction; a control unit for controlling operations of the vacuum adjustment unit, the temperature adjustment unit, and the pressurization unit; The control unit is a first process of increasing the degree of vacuum in the processing tank in which the laminate is accommodated by controlling the vacuum adjustment unit; a second process of controlling the temperature adjusting unit to raise the temperature of the stack to a predetermined first temperature to reduce and remove the passivation film of the plurality of plates; a third process of controlling the temperature adjustment unit to increase the temperature of the laminate to a predefined second temperature higher than the first temperature while the laminate is pressed by the pressurizing unit with a predefined pressure, thereby diffusion bonding the plurality of plates; and a fourth process of controlling the temperature adjusting unit to reduce the temperature of the laminate and the vacuum adjusting unit to reduce the degree of vacuum in the treatment tank in this order, A separator assembly manufacturing apparatus for manufacturing the separator assembly in which the separator A, in which the groove portion A is formed by the slit A and the blocking portion A, the separator B, in which the groove portion B is formed by the slit B and the blocking portion B, and the separator C, in which the groove portion C is formed by the slit C and the blocking portion C, are integrated together.

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