Fuel cell separator inspection system and fuel cell separator inspection method

Abstract

To provide a fuel cell separator inspection system and a fuel cell separator inspection method that perform inspection with high accuracy without applying an excessive load to the separator to be inspected.SOLUTION: A fuel cell separator inspection system includes a warpage correction jig that corrects warpage in a separator, and an inspection device that inspects the separator on the basis of a three-dimensional image of the separator captured while irradiating the separator held by the warpage correction jig with measurement light, and the warpage correction jig allows the measurement light to pass through.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present disclosure relates to an inspection system for a separator of a fuel cell and an inspection method for a separator of a fuel cell.

Background Art

[0002] A technique for inspecting a separator used in a fuel cell is disclosed in Patent Document 1. The inspection method for a separator of a fuel cell described in Patent Document 1 is an inspection method for inspecting the amount of warpage of the separator after molding. After the separator of the fuel cell is molded, a load simulating the load applied to the separator in the post-molding process is applied to the separator, the amount of warpage of the separator is measured, and when the measured amount of warpage of the separator is greater than a predetermined amount, the separator is determined to be a defective product.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Patent Document 1 describes applying a load simulating the load applied to the separator in the post-molding process of the separator by a warpage pressing jig, but this warpage pressing jig is not a jig for correcting the warpage of the separator that can affect the inspection accuracy.

[0005] Further, the technique described in Patent Document 1 has a problem that it is difficult to perform an inspection simulating the load applied to the separator during the use of the fuel cell mounted on a vehicle or the like. Therefore, in order to reproduce the load applied to the separator during the use of the fuel cell, it is conceivable to use a measuring device having a high pressing ability such as a universal testing machine, but there is a problem that the inspection cannot be performed when such a measuring device is not available.

[0006] Therefore, there is a need for a technology that can perform inspections with high accuracy assuming the use of a fuel cell mounted on a vehicle or the like without applying an excessive load to the separator to be inspected.

[0007] The present disclosure has been made to solve such problems, and an object thereof is to provide an inspection system for a separator of a fuel cell that performs inspections with high accuracy without applying an excessive load to the separator to be inspected, and an inspection method for a separator of a fuel cell.

Means for Solving the Problems

[0008] An inspection system for a separator of a fuel cell according to an embodiment includes a warp correction jig for correcting the warp of the separator, and an inspection device for inspecting the separator based on a three-dimensional image of the separator captured while irradiating the separator held by the warp correction jig with measurement light, and the warp correction jig transmits the measurement light.

Effects of the Invention

[0009] According to the present disclosure, it is possible to provide an inspection system for a separator of a fuel cell that performs inspections with high accuracy without applying an excessive load to the separator to be inspected, and an inspection method for a separator of a fuel cell.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Embodiments for Carrying Out the Invention

[0011] Embodiment 1 Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. However, the present disclosure is not limited to the following embodiments. Also, for clarity of explanation, the following description and drawings are simplified as appropriate. In the following description, the longitudinal direction of the separator 10 is defined as the X direction, the width direction of the separator 10 orthogonal to the X direction is defined as the Y direction, and the thickness direction of the separator 10 orthogonal to the X direction and the Y direction is defined as the Z direction.

[0012] The fuel cell has a stack structure in which one single cell or a plurality of single cells are stacked in the thickness direction. The single cell of the fuel cell has a membrane electrode gas diffusion layer assembly. The membrane electrode gas diffusion layer assembly has a membrane electrode assembly and a pair of gas diffusion layers joined so as to sandwich the membrane electrode assembly from both sides in the thickness direction. The membrane electrode assembly has an electrolyte membrane and a pair of electrodes joined so as to sandwich the electrolyte membrane from both sides in the thickness direction. The electrode disposed on one side of the electrolyte membrane functions as an anode, and the electrode on the other side functions as a cathode.

[0013] And the single cell has a pair of separators 10 that sandwich the membrane electrode gas diffusion layer assembly from both sides in its thickness direction. Therefore, FIG. 1 is a schematic diagram showing an example of the separator. Above FIG. 1, a front view of the separator 10 is shown. In the center of FIG. 1, an I-I cross-sectional view of the separator 10 is shown. Below FIG. 1, an II-II cross-sectional view of the separator 10 is shown. The separator 10 shown in FIG. 1 is adjacent to the membrane electrode gas diffusion layer assembly and contacts the gas diffusion layer. However, in the case of a fuel cell without a gas diffusion layer, the separator 10 may contact the membrane electrode assembly. Also, the separator 10 is adjacent to another separator 10 between adjacent single cells.

[0014] As shown in FIG. 1, the separator 10 is a gas-impermeable conductive member. As the conductive member, for example, a carbon composite material obtained by press-molding a mixture containing resin materials such as thermosetting resin, thermoplastic resin, and resin fiber, and carbon materials such as carbon powder and carbon fiber, a dense carbon obtained by compressing carbon to make it gas-impermeable, and a pressed metal (for example, titanium, iron, aluminum, and SUS, etc.) plate, etc. may be used. The separator 10 has a function of electrically connecting each single cell. Also, the separator 10 may have a current collecting function.

[0015] The separator 10 has holes 21 to 26 penetrating in the Z direction on its outer peripheral portion. These holes 21 to 26 form a manifold for supplying and discharging reaction gas (fuel gas or oxidizing gas) and refrigerant. The hole 21 disposed on one side in the X direction and one side in the Y direction of the separator 10 is a supply hole for supplying the reaction gas to a flow path through which the reaction gas (one of the fuel gas and the oxidizing gas) flows. The hole 26 disposed on the other side in the X direction and the other side in the Y direction of the separator 10 is a discharge hole for discharging the reaction gas from the flow path. The hole 24 disposed on one side in the X direction and at the center in the Y direction of the separator 10 is a supply hole for supplying the refrigerant to a flow path through which the refrigerant flows. The hole 25 disposed on the other side in the X direction and at the center in the Y direction of the separator 10 is a discharge hole for discharging the refrigerant from the flow path. The hole 23 disposed on one side in the X direction and the other side in the Y direction of the separator 10 is a supply hole for supplying the reaction gas (the other of the fuel gas and the oxidizing gas) to a flow path through which the reaction gas flows. The hole 26 disposed on the other side in the X direction and one side in the Y direction of the separator 10 is a discharge hole for discharging the reaction gas from the flow path.

[0016] The separator 10 has a concavo-convex flow path shape. The separator 10 has a plurality of gas flow path grooves 30 on a surface on one side in the Z direction (the surface facing the gas diffusion layer). The gas flow path grooves 30 form a flow path through which the reaction gas (fuel gas or oxidizing gas) flows between the gas diffusion layer.

[0017] The gas flow path groove 30 communicates the hole 21 and the hole 24. The gas flow path groove 30 has a pair of first gas flow path grooves 31, a pair of second gas flow path grooves 32, and a pair of flow path merging portions 33. The pair of first gas flow path grooves 31 are provided at the central portion of the separator 10 so as to extend in the X direction. The groove width of the first gas flow path groove 31 is, for example, about 0.5 mm. One of the second gas flow path grooves 32 is provided between the pair of first gas flow path grooves 31 and the hole 21 so as to communicate the pair of first gas flow path grooves 31 and the hole 21. The other second gas flow path groove 32 is provided between the pair of first gas flow path grooves 31 and the hole 24 so as to communicate the pair of first gas flow path grooves 31 and the hole 24. The groove width of the second gas flow path groove 32 is, for example, about 1.0 mm. One of the flow path merging portions 33 is a portion where the pair of first gas flow path grooves 31 and one of the second gas flow path grooves 32 merge on one side in the X direction. The other flow path merging portion 33 is a portion where the pair of first gas flow path grooves 31 and the other second gas flow path groove 32 merge on the other side in the X direction.

[0018] The reaction gas supplied from outside the separator 10 through the hole 21 passes through one of the second gas flow path grooves 32 and then flows through the pair of first gas flow path grooves 31 via one of the flow path merging portions 33. Then, the reaction gas flowing through the pair of first gas flow path grooves 31 passes through the other second gas flow path groove 32 via the other flow path merging portion 33 from the pair of first gas flow path grooves 31 and is then discharged to the outside of the separator 10 through the hole 24. Note that the directions in which the first gas flow path groove 31 and the second gas flow path groove 32 extend are not particularly limited, and these directions may be appropriately changed as needed. Further, the gas flow path groove 30 may be formed so as to communicate the hole 23 and the hole 26, for example, instead of communicating the hole 21 and the hole 24.

[0019] The separator 10 has a plurality of first ribs 41 and a plurality of second ribs 42 on one surface in the Z direction. The first ribs 41 are formed between the first gas flow path grooves 31 adjacent to each other in the Y direction. The first ribs 41 extend parallel to the adjacent first gas flow path grooves 31. The rib width of the first ribs 41 is, for example, about 1.2 mm. The second ribs 42 are formed between the gas flow path grooves 30 adjacent to each other in the Y direction. The second ribs 42 extend parallel to the adjacent gas flow path grooves 30. The rib width of the second ribs 42 is, for example, about 1.1 mm. The first ribs 41 and the second ribs 42 protrude on one side in the Z direction. In the plan view of FIG. 1, the portion surrounded by the broken line among the surfaces of the separator 10 where the gas flow path grooves 30 are formed is the contact portion 50 where the separator 10 (specifically, the first ribs 41) contacts the gas diffusion layer.

[0020] Furthermore, the separator 10 may have a plurality of refrigerant flow path grooves 60 on the other surface in the Z direction (the surface opposite to the surface facing the gas diffusion layer). The refrigerant flow path grooves 60 form a flow path through which the refrigerant flows between the separator 10 and another adjacent separator 10. The refrigerant flow path grooves 60 have a portion formed between the first gas flow path grooves 31 adjacent to each other in the Y direction. The refrigerant flow path grooves 60 communicate, for example, the hole 22 and the hole 25. The refrigerant supplied from the outside of the separator 10 through the hole 22 flows through the refrigerant flow path grooves 60 and is then discharged to the outside of the separator 10 through the hole 25. In the plan view of FIG. 1, the outer edge of the portion where the plurality of refrigerant flow path grooves 60 are formed is indicated by a long dashed line.

[0021] When inspecting the above-described separator 10, it is conceivable to use, for example, the inspection system 200 shown in FIG. 7. FIG. 7 is a side view for explaining the inspection system according to the comparative example. As shown in FIG. 7, the inspection system 200 according to the comparative example includes, as inspection devices, a universal testing machine 210 such as an autograph and a microscope (not shown). The universal testing machine 210 includes a test jig 220 having a block 221 and a flat plate 222 for fixing the test piece W, a stage 230 on which the test piece W fixed to the test jig 220 is placed, a pressure jig 240 movable in the vertical direction with respect to the stage 230, a drive device for moving the pressure jig 240, and a sensor 260 for detecting the load applied to the test piece W. Further, this inspection system 200 includes a control unit and the like having a processor, a memory, a storage device, and an interface circuit.

[0022] A method for inspecting the separator 10 using such an inspection system 200 will be described with reference to FIG. 8 together with FIG. 7. FIG. 8 is a flowchart showing the inspection method according to the comparative example. As shown in FIG. 8, the inspection method according to the comparative example is an inspection method for the separator 10 and includes steps S101 to S107.

[0023] First, in step S101, the control unit transfers the separator 10 to be inspected to the universal testing machine 210. The transfer of the separator 10 is performed by, for example, a transfer device (not shown) controlled by the control unit. Next, in step S102, first, a test piece W in which the gas diffusion layer 202 is laminated on the separator 10 through two pressure-sensitive papers 201 (A film and C film) is produced. The test piece W is produced by, for example, an operator. The test piece W thus produced is placed on the stage 230 of the universal testing machine 210 so as to be clamped from both sides by the test jig 220. Then, the control unit lowers the pressure-applying jig 240 by the driving device and applies a constant load (for example, 25 kN) along the thickness direction to the test piece W clamped by the test jig 220. Then, the control unit measures the surface pressure by detecting the load applied to the test piece W with the sensor 260. At this time, the flow path shape of the separator 10 is transferred to the pressure-sensitive paper 201.

[0024] Next, in step S103, the pressure-sensitive paper 201 on which the flow path shape is transferred is taken out from the test piece W, and it is confirmed whether there is any defect in the flow path shape. This confirmation is performed by, for example, an operator. In step S103, if there is no defect in the flow path shape transferred to the pressure-sensitive paper 201, the process proceeds to step S104. On the other hand, in step S103, if there is a defect in the flow path shape transferred to the pressure-sensitive paper 201, the process returns to step S102.

[0025] Next, in step S104, the control unit transfers the taken pressure-sensitive paper 201 to the microscope. The transfer of the pressure-sensitive paper 201 is performed, for example, by a transfer device (not shown) controlled by the control unit. In step S105, the control unit observes the pressure-sensitive paper 201 on which the channel shape is transferred with a microscope, and calculates the diameter of the inscribed circle of the portion corresponding to the channel confluence portion 33 of the separator 10. Next, in step S106, the control unit compares the calculated diameter of the inscribed circle with a threshold value (for example, φ1.7 mm or less). At this time, it is preferable to perform the comparison using the maximum value among the diameters of the inscribed circles measured for each of any 24 or more channel confluence portions 33. And in step S106, when the diameter of the inscribed circle is equal to or less than the threshold value (step S106: YES), the control unit determines that the separator 10 is a non-defective product and ends the series of processes. On the other hand, in step S106, when the diameter of the inscribed circle is larger than the threshold value (step S106: NO), the control unit determines that the separator 10 is a defective product and performs a process of prohibiting shipment in step S107.

[0026] However, in the above-described inspection system 200 and the inspection method using the inspection system 200, for example, the following problems occur. · Since each inspection includes a great deal of man-hours such as setup, it is time-consuming and laborious. · Since it is necessary to prepare the pressure-sensitive paper 201 and the gas diffusion layer 202 for each inspection, the inspection cost increases. · In order to reproduce the load applied to the separator 10 during the use of the fuel cell mounted on a vehicle or the like, an inspection device such as a universal testing machine 210 having a high pressurizing ability is required. Therefore, if such an inspection device is not available, the inspection cannot be performed.

[0027] Therefore, FIG. 2 is a side view for explaining the inspection system 100 according to Embodiment 1. As shown in FIG. 2, the inspection system 100 according to Embodiment 1 includes a warp correction jig 110 for correcting the warp of the separator 10, and a non-contact three-dimensional measuring machine 120 as an inspection device for inspecting the separator 10 based on a three-dimensional image of the separator 10 while irradiating the separator 10 held by the warp correction jig 110 with measurement light. The warp correction jig 110 allows the measurement light to pass through.

[0028] The inspection system 100 shown in FIG. 1 inspects the separator 10 based on a three-dimensional image of the separator 10 whose warp has been corrected by the warp correction jig 110. Thereby, the inspection can be performed with high accuracy without applying an excessive load to the separator 10 to be inspected. And the above problems occurring in the inspection system 200 and the inspection method using the inspection system 200 can also be solved.

[0029] Referring to FIG. 2, the detailed configuration of the inspection system 100 will be described. First, the warp correction jig 110 includes an upper plate 111 and a lower plate 112 that sandwich the separator 10. The upper plate 111 is disposed above the separator 10 so as to face the surface of the separator 10 on the side where the gas flow path groove 30 is provided. The lower plate 112 is disposed below the separator 10 so as to face the surface opposite to the surface on the side where the gas flow path groove 30 is provided. The warp correction jig 110 corrects the warp of the separator 10 by sandwiching the separator 10 between the upper plate 111 and the lower plate 112.

[0030] The upper plate 111 and the lower plate 112 are plate-shaped members formed of a transparent material that transmits measurement light. As the transparent material, a highly transparent material such as glass or a transparent resin can be used. From the viewpoints of the manufacturing cost of the jig and the ease of processing, it is preferable that the warp correction jig 110 is formed of a transparent resin. Examples of the transparent resin include acrylic resin (PMMA), polyethylene terephthalate (PET), polycarbonate (PC), and polyvinyl chloride (PVC). Since it has high transparency and is excellent in durability, impact resistance, and processability, the transparent resin is preferably an acrylic resin.

[0031] The three-dimensional measuring machine 120 includes a measuring unit 130 and a control unit 140. The measuring unit 130 irradiates the separator 10 on the stage 131 with measurement light, receives the measurement light reflected by the separator 10, and generates a captured image. The measuring unit 130 includes a stage 131, a light irradiation unit 132, and an imaging unit 133.

[0032] The stage 131 is a workbench having a horizontal and flat mounting surface for mounting the separator 10 sandwiched between the warp correction jigs 110. Further, a plurality of fastening holes are formed in the stage 131. A fastening member inserted through the upper plate 111 and the lower plate 112 is inserted into each fastening hole. The fastening member is a member that fixes the warp correction jig 110 to the stage 131. The plurality of fastening members may be arranged so as to surround the measurement target range. The measurement target range is preferably a non-contact portion of the surface of the separator 10 on the side where the gas flow path groove 30 is provided and where the separator 10 does not contact the gas diffusion layer. Since the flow path shape is less likely to change when a load is applied by the warp correction jig 110, the non-contact portion is suitable as the measurement target range. The stage 131 may be capable of operations such as rotation to adjust the imaging direction with respect to the separator 10.

[0033] The light irradiation unit 132 irradiates the separator 10 on the stage 131 with measurement light. The light irradiation unit 132 is composed of, for example, an irradiation light source, a collector lens, a pattern generation unit, and an irradiation lens. As the irradiation light source, for example, an LED (light emitting diode) or a halogen lamp that generates monochromatic measurement light can be used. The measurement light emitted from the irradiation light source enters the pattern generation unit through the collector lens. Then, the measurement light emitted from the pattern generation unit is irradiated onto the separator 10 on the stage 131 through the irradiation lens. The light irradiation unit 132 is disposed obliquely above the separator 10 placed on the stage 131.

[0034] The imaging unit 133 images the measurement light reflected by the separator 10 on the stage 131. The imaging unit 133 is composed of a light receiving lens and an imaging element. The imaging element receives the measurement light reflected by the separator 10 through the light receiving lens and generates a three-dimensional image. As the imaging element, for example, an image sensor such as a CCD (Charge Coupled Devices) or a CMOS (Complementary Metal Oxide Semiconductor) can be used. The imaging unit 133 is disposed above the separator 10 placed on the stage 131 so as to include at least the measurement target area in the imaging field of view. The imaging direction of the imaging unit 133 is inclined with respect to the irradiation direction of the light irradiation unit 132. The imaging unit 133 outputs the three-dimensional image to the control unit 140.

[0035] The control unit 140 is composed of, for example, a personal computer (PC) or the like. The control unit 140 includes a processor such as a CPU (Central Processing Unit), memories such as a ROM (Read Only Memory) and a RAM (Random Access Memory), a non-volatile storage device such as a hard disk drive (HDD), and an interface circuit for connecting peripheral devices. The storage device stores a control program for operating each part of the three-dimensional measuring machine 120 and an inspection program for inspecting the separator 10 based on the three-dimensional image input from the imaging unit 133. By the processor expanding and executing various programs stored in the storage device in the memory, various functions described later are realized.

[0036] The control unit 140 comprehensively controls the operations of each part of the three-dimensional measuring machine 120. The control unit 140 is connected to the measuring unit 130. The control unit 140 controls the operation of the stage 131, the irradiation of measurement light by the light irradiation unit 132, and the imaging by the imaging unit 133 according to the control program. In addition to the measuring unit 130, a display unit 150 such as a display and an input unit 160 such as a keyboard and a mouse are connected to the control unit 140. The display unit 150 displays on the screen a three-dimensional image input from the imaging unit 133, the three-dimensional shape F1 of the separator 10 based on the three-dimensional shape data, the cross-sectional shape F2, and the cross-sectional image F3 based on the two-dimensional image data, etc. The input unit 160 receives an input operation of an operator who inspects the separator 10.

[0037] Furthermore, the control unit 140 inspects the separator 10 by processing the three-dimensional image input from the imaging unit 133 according to the inspection program. In the present embodiment, the control unit 140 calculates the diameter of the inscribed circle C of the flow path confluence portion 33 of the separator 10 based on the three-dimensional shape data obtained by analyzing the three-dimensional image of the separator 10 captured by the imaging unit 133, and determines whether the separator 10 is a defective product based on the calculation result.

[0038] The functions of the control unit 140 related to the above-described inspection will be described. The control unit 140 includes an analysis unit 141, a reference plane creation unit 142, an offset plane creation unit 143, a calculation unit 144, and a determination unit 145.

[0039] The analysis unit 141 generates three-dimensional shape data by analyzing a three-dimensional image. The reference plane creation unit 142 creates a reference plane P15 based on the position information of the tops of the first rib 41 and the second rib 42 in contact with the flow path confluence portion 33 included in the three-dimensional shape data. The offset plane creation unit 143 creates an offset plane P16 that is separated from the reference plane P15 by a predetermined distance toward the bottom side of the gas flow path groove 30. The calculation unit 144 calculates the diameter of the inscribed circle C of the flow path confluence portion 33 based on the two-dimensional image data indicating the offset plane P16. The determination unit 145 determines that the separator 10 is a defective product when the calculated diameter of the inscribed circle C is larger than the threshold value. When the above-described determination is made by an operator, the determination unit 145 can be omitted.

[0040] A separator 10 having an inscribed circle C with a diameter larger than the threshold value may cause a problem that the electrolyte membrane is torn and the power generation performance deteriorates due to the load applied to the separator 10 and the membrane electrode gas diffusion layer assembly during the use of the fuel cell mounted on a vehicle or the like. Therefore, it is determined as a defective product at the inspection stage.

[0041] The inspection method according to Embodiment 1 using the above-described inspection system 100 will be described with reference to FIG. 3. FIG. 3 is a flowchart for explaining the inspection method according to Embodiment 1. As shown in FIG. 3, the inspection method according to Embodiment 1 includes a warp correction step (step S10), an imaging step (step S20), and an inspection step (step S30).

[0042] Step S10 is a warp correction process of correcting the warp of the separator 10 by the warp correction jig 110. For example, when the separator 10 is directly placed on the stage 131, a warp occurs in which the separator 10 partially lifts off the stage 131 due to the distortion generated inside the separator 10. If the imaging process described later is performed with the separator 10 warped, the reflection angle of the measurement light changes, so the inspection accuracy in the inspection process described later decreases. Therefore, by sandwiching the separator 10 with the warp correction jig 110, the warp of the separator 10 that can affect the inspection accuracy is corrected, and high inspection accuracy can be obtained. The warp correction jig 110 sandwiching the separator 10 is fixed to the stage 131 by an operator using a fastening member.

[0043] Step S20 is an imaging process of imaging a three-dimensional image of the separator 10 while irradiating the separator 10 sandwiched by the warp correction jig 110 with measurement light. In the imaging process, according to the control of the control unit 140, the light irradiation unit 132 irradiates the separator 10 on the stage 131 with measurement light. Then, according to the control of the control unit 140, the imaging unit 133 receives the measurement light reflected by the separator 10 on the stage 131 and generates a three-dimensional image based on the received measurement light.

[0044] Step S30 is an inspection process of inspecting the separator 10 based on the three-dimensional image of the separator 10 imaged in the imaging process. The inspection process includes an analysis process (step S31), a reference plane creation (step S32), an offset plane creation process (step S33), a calculation process (step S34), and a determination process (step S35).

[0045] First, step S31 is an analysis step of generating three-dimensional shape data by analyzing a three-dimensional image. In the analysis step, the analysis unit 141 analyzes the three-dimensional image by a predetermined measurement algorithm to generate three-dimensional data. The three-dimensional shape data is created based on the three-dimensional image acquired from the imaging unit 133. The three-dimensional shape data includes a point cloud including a large number of points including position information in three-dimensional space coordinates. The three-dimensional shape data may be generated based on a plurality of three-dimensional images with different imaging directions as necessary. Here, FIG. 4 is a diagram for explaining the analysis step (step S31) and the reference plane creation step (step S32). As shown in FIG. 4, the three-dimensional shape data is displayed on the screen of the display unit 150 as a three-dimensional shape F1.

[0046] Next, step S32 will be described with reference to FIG. 4. The reference plane creation step is a step of creating a reference plane P15 based on the position information of the tops of the first rib 41 and the second rib 42 in contact with the flow path confluence portion 33 included in the three-dimensional shape data.

[0047] The reference plane P15 is a plane used as a reference when creating the offset plane P16. In the reference plane creation step, the reference plane creation unit 142 selects a point cloud for creating the reference plane P15 based on the specified position with respect to the three-dimensional shape F1. The specification of the position with respect to the three-dimensional shape F1 is performed, for example, by an operator's operation via the input unit 160. The operator designates, on the screen, the planes P11, P12, and P13 including the points indicating the tops of the pair of first rib 41 and second rib 42 in contact with the flow path confluence portion 33 as positions, and thus a point cloud for creating the reference plane P15 is selected. At this time, in order to set the average of the planes respectively created at the three tops in contact with the flow path confluence portion 33 as the reference plane P15, it is preferable to specify the planes P11, P12, and P13 in contact with the flow path confluence portion 33.

[0048] The plane P11 is specified on the first rib 41 between the pair of first gas flow path grooves 31. The plane P12 is specified on one of the second ribs 42 adjacent to the gas flow path groove 30. The plane P13 is specified on the other second rib 42 adjacent to the gas flow path groove 30. Then, based on the specified planes P11, P12, and P13, the reference plane creation unit 142 generates a reference plane P15 that is the average of the planes P11, P12, and P13.

[0049] Next, step S33 will be described with reference to FIG. 5. FIG. 5 is a diagram for explaining the offset plane creation process (step S33). FIG. 5 shows the cross-sectional shape F2 of the separator 10 displayed on the screen of the display unit 150. This cross-sectional shape F2 shows a part of the cross-section along the Z direction of the separator 10. Step S33 is an offset plane creation process for creating an offset plane P16 that is separated from the reference plane P15 by a predetermined distance toward the bottom side of the gas flow path groove 30. The offset plane P16 is a plane parallel to the reference plane P15. The predetermined distance when creating the offset plane P16 is stored in the storage device in advance.

[0050] As shown in FIG. 5, the predetermined distance when creating the offset plane P16 is preferably 20 μm. Thereby, an inspection assuming the use of a fuel cell mounted on a vehicle or the like can be realized. The predetermined distance can be determined by experiments or the like. Here, when a load is applied to a single cell, the portion of the gas diffusion layer in contact with the separator 10 that faces the gas flow path groove 30 bends and deforms, and bends into the gas flow path groove 30. Therefore, the inventors conducted an experiment to confirm the amount of bending of the gas diffusion layer in contact with the separator 10.

[0051] Specifically, when a load (25.5 kN) was applied to the separator 10 through the gas diffusion layer from above the gas flow path groove 30 to obtain the amount of bending of the gas diffusion layer, it was found that when the applied load was 25.5 kN, the ability value considering the variation in the amount of bending was 20 μm. Based on such experimental results, the predetermined distance when creating the offset plane P16 was determined to be 20 μm.

[0052] Next, referring to FIG. 6, step S34 will be described. FIG. 6 is a diagram for explaining the calculation step (step S34). Step S34 is a step of calculating the diameter of the inscribed circle C of the flow path confluence portion 33 based on the two-dimensional image data showing the offset plane P16. FIG. 6 shows the cross-sectional image F3 displayed on the screen of the display unit 150.

[0053] In the calculation step, the calculation unit 144 selects points for creating the inscribed circle C based on the designation of the position with respect to the cross-sectional image F3. The designation of the position with respect to the cross-sectional image F3 is performed, for example, by the operation of the operator via the input unit 160. When the operator designates points P21, P22, and P23 as positions on the boundary lines L1, L2, and L3 in contact with the flow path confluence portion 33 on the screen, the points for creating the inscribed circle C are selected. The point P21 is designated on the boundary line L1 between the pair of first gas flow path grooves 31 and the first rib 41. The point P22 is designated on the boundary line L2 between the gas flow path groove 30 and one of the second ribs 42 adjacent to the gas flow path groove 30. The point P23 is designated on the boundary line L3 between the gas flow path groove 30 and the other second rib 42 adjacent to the gas flow path groove 30. In the calculation step, the calculation unit 144 obtains the diameter of the inscribed circle C passing through the points P21, P22, and P23.

[0054] Next, step S35 is a determination step of determining that the separator 10 is a defective product when the calculated diameter of the inscribed circle C is larger than the threshold value. The threshold value used for the determination is stored in the storage device in advance. In the determination step, the determination unit 145 compares the diameter of the inscribed circle C calculated in the calculation step with the threshold value (for example, φ1.7 mm or less). At this time, it is preferable to perform the comparison using the maximum value among the diameters of the inscribed circles C calculated for each of any 24 or more flow path confluence portions 33. The threshold value is set to a value at which the electrolyte membrane does not cause membrane rupture due to the load applied to the separator 10 and the membrane electrode gas diffusion layer assembly during the use of the fuel cell mounted on a vehicle or the like.

[0055] Then, as shown in FIG. 3, in step S35, when the diameter of the inscribed circle C is equal to or less than the threshold value (step S35: YES), the control unit 140 determines that the separator 10 is a non-defective product and ends the series of processes. On the other hand, in step S35, when the diameter of the inscribed circle C is greater than the threshold value (step S35: NO), the control unit 140 determines that the separator 10 is a defective product and performs a process of prohibiting shipment in step S36.

[0056] As described above, according to the inspection system 100 and the inspection method according to the first embodiment, the inspection can be performed without applying an excessive load to the separator 10 to be inspected. And since it is possible to determine whether the separator 10 is a defective product at the inspection stage, it is possible to suppress defects of the separator 10 that may occur during the use of the fuel cell mounted on a vehicle or the like.

[0057] Note that the present disclosure is not limited to the above-described embodiment, and can be appropriately changed without departing from the gist. For example, the inspection device is not limited to the three-dimensional measuring machine 120, and a one-shot 3D shape measuring machine, a 3D laser scanner, or the like can be used.

Description of Reference Numerals

[0058] 10 Separator 21, 22, 23, 24, 25, 26 holes 30 Gas flow path groove 31 First gas flow path groove 32 Second gas flow path groove 33 Flow path confluence part 41 First rib 42 Second rib 50 Contact part 60 Refrigerant flow path groove 100 Inspection system 110 Warpage correction jig 111 Upper plate 112 Lower plate 120 Three-dimensional measuring machine 130 Measuring part 131 Stage 132 Light irradiation part 133 Imaging part 140 Control unit 141 Analysis part 142 Reference plane creation part 143 Offset plane creation part 144 Calculation part 145 Determination part 150 Display part 160 Input part 200 Inspection System 201 Pressure Sensitive Paper 202 Gas Diffusion Layer 210 Universal Testing Machine 220 Test Fixture 221 Block 222 Flat Plate 230 Stage 240 Pressing Fixture 260 Sensor C Inscribed Circle F1 Three - dimensional Shape F2 Cross - sectional Shape F3 Cross - sectional Image L1, L2, L3 Boundary Lines P11, P12, P13 Planes P15 Reference Plane, P16 Offset Plane P21, P22, P23 Points W Specimen

Claims

1. A warp correcting jig for correcting the warp of a separator, and an inspection apparatus for inspecting the separator based on a three-dimensional image of the separator taken while irradiating the separator held by the warp correcting jig with measurement light, and having, a separator inspection system for a fuel cell, wherein the warp correcting jig transmits the measurement light.

2. The separator inspection system for a fuel cell according to claim 1, wherein the warp correcting jig is formed of a transparent resin.

3. The separator has, a plurality of first gas flow path grooves, second gas flow path grooves, and a plurality of gas flow path grooves including a flow path confluence portion where the plurality of first gas flow path grooves and the second gas flow path grooves merge, a first rib formed between the adjacent first gas flow path grooves, a second rib formed between the adjacent gas flow path grooves, on one surface in the thickness direction, The inspection apparatus has, an analysis unit that generates three-dimensional shape data by analyzing the three-dimensional image, a reference plane creation unit that creates a reference plane based on the position information of the top portions of the first rib and the second rib in contact with the flow path confluence portion included in the three-dimensional shape data, an offset plane creation unit that creates an offset plane separated from the reference plane by a predetermined distance toward the bottom side of the gas flow path groove, a calculation unit that calculates the diameter of the inscribed circle of the flow path confluence portion based on two-dimensional image data indicating the offset plane, and a control unit including the same, and is the separator inspection system for a fuel cell according to claim 1.

4. The separator inspection system for a fuel cell according to claim 3, wherein the control unit includes a determination unit that determines the separator as a defective product when the calculated diameter of the inscribed circle is larger than a threshold value.

5. A warp correction step of correcting the warp of the separator with a warp correcting jig, and an inspection step of inspecting the separator based on a three-dimensional image of the separator taken while irradiating the separator held by the warp correcting jig with measurement light, and having, a separator inspection method for a fuel cell, wherein the warp correcting jig transmits the measurement light.

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