Inspection system for fuel cell separators, and inspection method for fuel cell separators.

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 a method for inspecting 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 the separator of the fuel cell described in Patent Document 1 is an inspection method for inspecting the amount of warp 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 warp of the separator is measured, and when the measured amount of warp 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 warp suppressing jig, but this warp suppressing jig is not a jig for correcting the warp of the separator that can affect the inspection accuracy.

[0005] Further, in the technique described in Patent Document 1, there is a problem that it is difficult to perform an inspection simulating the load applied to the separator when the fuel cell mounted on a vehicle or the like is in use. Therefore, in order to reproduce the load applied to the separator when the fuel cell is in use, it is conceivable to use a measuring device having a high pressurizing 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 technology that can perform inspections with high accuracy, simulating the operation of fuel cells mounted on vehicles, etc., without applying excessive load to the separator being inspected.

[0007] This disclosure was made to solve such problems and aims to provide a fuel cell separator inspection system and a fuel cell separator inspection method that can perform inspections with high accuracy without applying excessive load to the separator being inspected. [Means for solving the problem]

[0008] An inspection system for a fuel cell separator according to one embodiment comprises 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, which is held between the warp correction jig, with the warp correction jig allowing the measurement light to pass through. [Effects of the Invention]

[0009] This disclosure provides a fuel cell separator inspection system and a fuel cell separator inspection method that perform inspections with high accuracy without applying excessive load to the separator being inspected. [Brief explanation of the drawing]

[0010] [Figure 1] This is a schematic diagram showing an example of a separator. [Figure 2] This is a side view illustrating the inspection system according to Embodiment 1. [Figure 3] This is a flowchart illustrating the inspection method according to Embodiment 1. [Figure 4] This diagram illustrates the analysis process (step S31) and the reference plane creation process (step S32). [Figure 5] This is a diagram illustrating the offset plane creation process (step S33). [Figure 6] This is a diagram illustrating the calculation process (step S34). [Figure 7] This is a side view illustrating the inspection system used in the comparative example. [Figure 8] This is a flowchart explaining the inspection method for the comparative example. [Modes for carrying out the invention]

[0011] Embodiment 1 Embodiments of the present disclosure will be described below 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 have been 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 perpendicular to the X direction is defined as the Y direction, and the thickness direction of the separator 10 perpendicular to the X and Y directions is defined as the Z direction.

[0012] A fuel cell has a stack structure in which one or more single cells are stacked in the thickness direction. A single cell of a 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 located on one side of the electrolyte membrane functions as the anode, and the electrode on the other side functions as the cathode.

[0013] Each single cell has a pair of separators 10 that sandwich the membrane electrode gas diffusion layer assembly from both sides in the thickness direction. Figure 1 is a schematic diagram showing an example of a separator. The upper part of Figure 1 shows a front view of the separator 10. The center of Figure 1 shows a cross-sectional view II of the separator 10. The lower part of Figure 1 shows a cross-sectional view II-II of the separator 10. The separator 10 shown in Figure 1 is adjacent to the membrane electrode gas diffusion layer assembly and is in contact with the gas diffusion layer. However, in the case of a fuel cell without a gas diffusion layer, the separator 10 may be in contact with the membrane electrode assembly. Also, the separator 10 is adjacent to other separators 10 between adjacent single cells.

[0014] As shown in Figure 1, the separator 10 is a gas-impermeable conductive member. The conductive member may be, for example, a carbon composite material obtained by press-molding a mixture containing resin materials such as thermosetting resins, thermoplastic resins, and resin fibers, and carbon materials such as carbon powder and carbon fibers; dense carbon, which is compressed to be gas-impermeable; or a press-molded metal plate (e.g., titanium, iron, aluminum, and SUS, etc.). The separator 10 has the function of electrically connecting each single cell. The separator 10 may also have a current collection function.

[0015] The separator 10 has holes 21 to 26 on its outer circumference that penetrate in the Z direction. These holes 21 to 26 form a manifold for supplying and discharging reaction gas (fuel gas or oxidizing gas) and refrigerant. Hole 21, located on one side of the separator 10 in the X direction and one side in the Y direction, is a supply hole that supplies the reaction gas (either fuel gas or oxidizing gas) to the flow path. Hole 26, located on the other side of the separator 10 in the X direction and the other side in the Y direction, is a discharge hole that discharges the reaction gas from the flow path. Hole 24, located on one side of the separator 10 in the X direction and in the center in the Y direction, is a supply hole that supplies the refrigerant to the flow path. Hole 25, located on the other side of the separator 10 in the X direction and in the center in the Y direction, is a discharge hole that discharges the refrigerant from the flow path. The hole 23 located on one side of the separator 10 in the X direction and the other side in the Y direction is a supply hole that supplies the reaction gas (the other of the fuel gas and the oxidizing gas) to the flow path. The hole 26 located on the other side of the separator 10 in the X direction and the one side in the Y direction is a discharge hole that discharges the reaction gas from the flow path.

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

[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 in 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 the outside of the separator 10 through the hole 21 flows through one of the second gas flow path grooves 32, then through one of the flow path merging portions 33 into the pair of first gas flow path grooves 31. The reaction gas flowing through the pair of first gas flow path grooves 31 passes through the other second gas flow path groove 32 from the pair of first gas flow path grooves 31 through the other flow path merging portion 33, and then is 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, instead of communicating the hole 21 and the hole 24, the gas flow path groove 30 may be formed to communicate, for example, the hole 23 and the hole 26.

[0019] 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 adjacent first gas flow path grooves 31 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 adjacent gas flow path grooves 30 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 adjacent other separators 10. The refrigerant flow path grooves 60 have a portion formed between adjacent first gas flow path grooves 31 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 shown by a long chain line.

[0021] When inspecting the separator 10 described above, it is conceivable to use, for example, the inspection system 200 shown in Figure 7. Figure 7 is a side view illustrating the inspection system according to the comparative example. As shown in Figure 7, the inspection system 200 according to the comparative example has, for example, a universal testing machine 210 such as an autograph, and a microscope (not shown) as inspection equipment. The universal testing machine 210 has a test fixture 220 having a block 221 and a flat plate 222 for fixing the test specimen W, a stage 230 on which the test specimen W fixed to the test fixture 220 is placed, a pressure fixture 240 that can move vertically relative to the stage 230, a drive device for moving the pressure fixture 240, and a sensor 260 for detecting the load applied to the test specimen W. Furthermore, this inspection system 200 has a control unit having a processor, memory, storage device, and interface circuit.

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

[0023] First, in step S101, the control unit transports the separator 10 to be inspected to the universal testing machine 210. The transport of the separator 10 is performed, for example, by a transport device (not shown) controlled by the control unit. Next, in step S102, a test specimen W is first prepared by laminating a gas diffusion layer 202 onto the separator 10 via two pressure-sensitive papers 201 (A film and C film). The test specimen W is prepared, for example, by an operator. The test specimen W thus prepared is placed on the stage 230 of the universal testing machine 210 so as to be held from both sides by a test fixture 220. The control unit then lowers the pressure fixture 240 using a drive device to apply a constant load (for example, 25kN) along its thickness direction to the test specimen W held by the test fixture 220. The control unit then measures the surface pressure by detecting the load applied to the test specimen W with a 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 has been transferred is removed from the test specimen W, and it is checked whether or not there are any defects in the flow path shape. This check is performed, for example, by an operator. If no defects are found in the flow path shape transferred to the pressure-sensitive paper 201 in step S103, the process proceeds to step S104. On the other hand, if defects are found in the flow path shape transferred to the pressure-sensitive paper 201 in step S103, the process returns to step S102.

[0025] Next, in step S104, the control unit transfers the removed 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 flow path shape has been transferred using the microscope and calculates the diameter of the inscribed circle of the portion corresponding to the flow path confluence 33 of the separator 10. Next, in step S106, the control unit compares the calculated diameter of the inscribed circle with a threshold (for example, φ1.7 mm or less). At this time, it is preferable to use the maximum value among the diameters of the inscribed circles measured for each of the 24 or more arbitrary flow path confluence 33 for the comparison. Then, in step S106, if the diameter of the inscribed circle is less than or equal to the threshold (step S106: YES), the control unit determines that the separator 10 is a good product and terminates the series of processes. On the other hand, in step S106, if the diameter of the inscribed circle is greater than the threshold (step S106: NO), the control unit determines that the separator 10 is defective and performs a shipment prohibition process in step S107.

[0026] However, the inspection system 200 and the inspection method using the inspection system 200 described above have the following problems, for example. Each inspection involves a significant amount of preparation and setup, making it time-consuming and labor-intensive. • Since pressure-sensitive paper 201 and gas diffusion layer 202 need to be prepared for each test, the testing cost increases. • In order to reproduce the load applied to the separator 10 when a fuel cell mounted on a vehicle is in use, an inspection device such as a universal testing machine 210 with high pressurization capacity is necessary. If such an inspection device is not available, the inspection cannot be performed.

[0027] Therefore, Figure 2 is a side view illustrating the inspection system 100 according to Embodiment 1. As shown in Figure 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 captured while irradiating the separator 10, which is held between the warp correction jig 110, with measuring light. The warp correction jig 110 transmits the measuring light.

[0028] The inspection system 100 shown in Figure 1 inspects the separator 10 based on a three-dimensional image of the separator 10 whose warping has been corrected by the warping correction jig 110. This allows for highly accurate inspection without applying excessive load to the separator 10 being inspected. Furthermore, the above-mentioned problems that occur with the inspection system 200 and the inspection method using the inspection system 200 can be solved.

[0029] Referring to Figure 2, the detailed configuration of the inspection system 100 will be described. First, the warp correction jig 110 has an upper plate 111 and a lower plate 112 that clamp the separator 10. The upper plate 111 is positioned above the separator 10 so as to face the side of the separator 10 on which the gas flow channel groove 30 is provided. The lower plate 112 is positioned below the separator 10 so as to face the side opposite to the side on which the gas flow channel groove 30 is provided. The warp correction jig 110 corrects the warp of the separator 10 by clamping 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 from a transparent material that transmits measurement light. Highly transparent materials such as glass and transparent resin can be used as the transparent material. From the viewpoint of jig manufacturing cost and ease of processing, it is preferable that the warp correction jig 110 is formed from transparent resin. Examples of transparent resins include acrylic resin (PMMA), polyethylene terephthalate (PET), polycarbonate (PC), and polyvinyl chloride (PVC). Acrylic resin is preferred as the transparent resin because it has high transparency and excellent durability, impact resistance, and processability.

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

[0032] Stage 131 is a workbench having a horizontal and flat mounting surface for placing the separator 10, which is held in place by the warp correction jig 110. Stage 131 also has a plurality of fastening holes. Fastening members, inserted through the upper plate 111 and the lower plate 112, are inserted through each fastening hole. The fastening members are used to fix the warp correction jig 110 to Stage 131. The plurality of fastening members are preferably arranged to surround the measurement target area. The measurement target area is preferably a non-contact portion of the side of the separator 10 where the gas flow channel groove 30 is provided, where the separator 10 does not come into contact with the gas diffusion layer. The non-contact portion is suitable as the measurement target area because the flow channel shape is less likely to change when a load is applied by the warp correction jig 110. Stage 131 may be capable of rotation or other movements to adjust the imaging direction relative 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. For 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 via the collector lens. The measurement light emitted from the pattern generation unit then irradiates the separator 10 on the stage 131 via the irradiation lens. The light irradiation unit 132 is positioned diagonally above the separator 10 placed on the stage 131.

[0034] The imaging unit 133 captures 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 image sensor. The image sensor receives the measurement light reflected by the separator 10 via the light-receiving lens and generates a three-dimensional image. For the image sensor, an image sensor such as a CCD (Charge Coupled Device) or CMOS (Complementary Metal Oxide Semiconductor) can be used. The imaging unit 133 is positioned above the separator 10 placed on the stage 131 so as to include at least the measurement target area in its 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). The control unit 140 has a processor such as a CPU (Central Processing Unit), memory such as ROM (Read Only Memory) and 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 controlling the operation of 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. The processor loads the various programs stored in the storage device into memory and executes them, thereby realizing the various functions described later.

[0036] The control unit 140 comprehensively controls the operation 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, the control unit 140 is also connected to a display unit 150 such as a display, and an input unit 160 such as a keyboard or mouse. The display unit 150 displays the three-dimensional image input from the imaging unit 133, the three-dimensional shape F1 and cross-sectional shape F2 of the separator 10 based on three-dimensional shape data, and the cross-sectional image F3 based on two-dimensional image data on the screen. The input unit 160 accepts input operations from the operator performing the inspection of 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 this embodiment, the control unit 140 calculates the diameter of the inscribed circle C of the flow channel confluence 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 or not the separator 10 is defective based on the calculation result.

[0038] The functions of the control unit 140 related to the inspection described above will now be explained. 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, which are in contact with the flow channel confluence 33 and are included in the three-dimensional shape data. The offset plane creation unit 143 creates an offset plane P16 located a predetermined distance from the reference plane P15 towards the bottom of the gas flow channel groove 30. The calculation unit 144 calculates the diameter of the inscribed circle C of the flow channel confluence 33 based on the two-dimensional image data showing the offset plane P16. The determination unit 145 determines the separator 10 to be defective if the calculated diameter of the inscribed circle C is greater than a threshold. Note that if the above determination is performed by an operator, the determination unit 145 can be omitted.

[0040] A separator 10 whose inscribed circle C diameter is greater than the threshold may be judged as defective during inspection because the electrolyte membrane may rupture due to the load applied to the separator 10 and the membrane electrode gas diffusion layer assembly when the fuel cell is used in a vehicle or the like, resulting in a decrease in power generation performance.

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

[0042] Step S10 is a warp correction process in which the warp of the separator 10 is corrected using a warp correction jig 110. For example, if the separator 10 is placed directly on the stage 131, the distortion generated inside the separator 10 will cause warping, which will cause the separator 10 to partially lift off the stage 131. If the imaging process described later is performed with the separator 10 warped, the reflection angle of the measurement light will change, which will reduce the inspection accuracy in the inspection process described later. Therefore, by clamping the separator 10 in the warp correction jig 110, the warp of the separator 10 that may affect the inspection accuracy is corrected, and high inspection accuracy can be obtained. The warp correction jig 110, with the separator 10 clamped in place, is fixed to the stage 131 by the operator using fastening members.

[0043] Step S20 is an imaging process in which a three-dimensional image of the separator 10, which is held by the warp correction jig 110, is captured while irradiating it with measurement light. In the imaging process, the light irradiation unit 132 irradiates the separator 10 on the stage 131 with measurement light according to the control unit 140. Then, according to 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 step in which the separator 10 is inspected based on the three-dimensional image of the separator 10 captured in the imaging step. The inspection step includes an analysis step (step S31), a reference plane creation step (step S32), an offset plane creation step (step S33), a calculation step (step S34), and a determination step (step S35).

[0045] First, step S31 is an analysis step in which three-dimensional shape data is generated by analyzing a three-dimensional image. In the analysis step, the analysis unit 141 analyzes the three-dimensional image using a predetermined measurement algorithm and generates 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 containing a large number of points that include position information in three-dimensional spatial coordinates. The three-dimensional shape data may be generated based on multiple three-dimensional images with different imaging directions, if necessary. Here, Figure 4 is a diagram illustrating the analysis step (step S31) and the reference plane creation step (step S32). As shown in Figure 4, the three-dimensional shape data is displayed as a three-dimensional shape F1 on the screen of the display unit 150.

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

[0047] The reference plane P15 is the plane used as a reference when creating the offset plane P16. In the reference plane creation process, the reference plane creation unit 142 selects a point cloud for creating the reference plane P15 based on the specification of a position relative to the three-dimensional shape F1. The specification of a position relative to the three-dimensional shape F1 is performed, for example, by an operator via the input unit 160. The operator selects the point cloud for creating the reference plane P15 by specifying, on the screen, as the position of a point cloud that includes points representing the vertices of the pair of first ribs 41 and second ribs 42 that are tangent to the flow channel confluence 33. At this time, it is preferable to specify the planes P11, P12, and P13 that are tangent to the flow channel confluence 33 in order to use the average of the faces created at the three vertices tangent to the flow channel confluence 33 as the reference plane P15.

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

[0049] Next, step S33 will be explained with reference to Figure 5. Figure 5 is a diagram illustrating the offset plane creation process (step S33). Figure 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 of the separator 10 along the Z direction. Step S33 is an offset plane creation process in which an offset plane P16 is created at a predetermined distance from the reference plane P15 towards the bottom of the gas flow channel groove 30. The offset plane P16 is a plane parallel to the reference plane P15. The predetermined distance for creating the offset plane P16 is stored in advance in the memory device.

[0050] As shown in Figure 5, the predetermined distance when creating the offset plane P16 is preferably 20 μm. This makes it possible to perform inspections simulating the use of a fuel cell mounted on a vehicle or the like. This predetermined distance can be determined by experimentation. Here, when a load is applied to the single cell, the portion of the gas diffusion layer in contact with the separator 10 that faces the gas flow channel groove 30 deforms and flexes into the gas flow channel groove 30. Therefore, the inventors conducted an experiment to confirm the amount of flexing of the gas diffusion layer in contact with the separator 10.

[0051] Specifically, when a load (25.5kN) was applied to the separator 10 from above the gas flow channel groove 30 via the gas diffusion layer, the amount of deflection of the gas diffusion layer was determined. It was found that when the applied load was 25.5kN, the capacity value, taking into account the variation in the amount of deflection, was 20μm. Based on these experimental results, the predetermined distance for creating the offset plane P16 was determined to be 20μm.

[0052] Next, step S34 will be explained with reference to Figure 6. Figure 6 is a diagram illustrating the calculation process (step S34). Step S34 is a process of calculating the diameter of the inscribed circle C of the flow channel confluence 33 based on two-dimensional image data showing the offset plane P16. Figure 6 shows the cross-sectional image F3 displayed on the screen of the display unit 150.

[0053] In the calculation process, the calculation unit 144 selects points to create the inscribed circle C based on the specified positions relative to the cross-sectional image F3. The specification of positions relative to the cross-sectional image F3 is performed, for example, by the operator via the input unit 160. The operator selects points to create the inscribed circle C by specifying points P21, P22, and P23 as positions on the screen, on the boundary lines L1, L2, and L3 tangent to the flow channel confluence section 33. Point P21 is specified on the boundary line L1 between a pair of first gas flow channel grooves 31 and a first rib 41. Point P22 is specified on the boundary line L2 between the gas flow channel groove 30 and one of the second ribs 42 adjacent to the gas flow channel groove 30. Point P23 is specified on the boundary line L3 between the gas flow channel groove 30 and the other second rib 42 adjacent to the gas flow channel groove 30. In the calculation process, the calculation unit 144 determines the diameter of the inscribed circle C passing through points P21, P22, and P23.

[0054] Next, step S35 is a determination step in which the separator 10 is determined to be a defective product if the calculated diameter of the inscribed circle C is greater than a threshold. The threshold used for determination is stored in advance in a memory device. In the determination step, the determination unit 145 compares the diameter of the inscribed circle C calculated in the calculation step with the threshold (for example, φ1.7 mm or less). At this time, it is preferable to use the maximum value among the diameters of the inscribed circle C calculated for each of the 24 or more arbitrary flow channel confluence sections 33 for the comparison. The threshold is set to a value such that the electrolyte membrane does not tear due to the load applied to the separator 10 and the membrane electrode gas diffusion layer assembly when the fuel cell mounted on a vehicle or the like is in use.

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

[0056] As described above, the inspection system 100 and inspection method according to Embodiment 1 allow inspection to be performed without applying an excessive load to the separator 10 to be inspected. Furthermore, since it is possible to determine whether or not the separator 10 is defective at the inspection stage, malfunctions of the separator 10 that may occur when a fuel cell mounted on a vehicle or the like is in use can be suppressed.

[0057] This disclosure is not limited to the embodiments described above, and can be modified as appropriate without departing from the spirit of the invention. For example, the inspection device is not limited to the three-dimensional measuring machine 120, but can also be a one-shot 3D shape measuring machine, a 3D laser scanner, or the like. [Explanation of Symbols]

[0058] 10 Separator holes 21, 22, 23, 24, 25, 26 30 Gas flow channel groove 31 First gas flow channel groove 32 Second gas flow channel groove 33 Flow channel junction 41 First rib 42 Second rib 50 Contact area 60 Coolant flow groove 100 Inspection system 110 Warping correction jig 111 Upper plate 112 Lower plate 120 Three-dimensional measuring machine 130 Measuring unit 131 Stage 132 Light irradiation unit 133 Imaging unit 140 Control Unit 141 Analysis Unit 142 Reference Plane Creation Unit 143 Offset plane creation unit 144 Calculation unit 145 Determination unit 150 Display unit 160 Input unit 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 Pressurizing fixture 260 Sensor C Inscribed circle F1 Solid shape F2 Cross-sectional shape F3 Cross-sectional image L1, L2, L3 boundary line P11, P12, P13 plane P15 Reference plane, P16 Offset plane, P21, P22, P23 Points W Test Specimen

Claims

1. A warp correction jig for correcting the warping of separators, The inspection device includes a three-dimensional image of the separator, which is captured while the separator is held by the warp correction jig and irradiated with measuring light, and the device inspects the separator based on this image. An inspection system for fuel cell separators, wherein the warping correction jig transmits the measurement light.

2. The inspection system for a fuel cell separator according to claim 1, wherein the warping correction jig is made of transparent resin.

3. The aforementioned separator is, A plurality of gas flow channels including a plurality of first gas flow channel channels, a second gas flow channel channel, and a flow channel confluence section where the plurality of first gas flow channel channels and the second gas flow channel channels merge, A first rib formed between adjacent first gas flow channel grooves, A second rib formed between the adjacent gas flow channel grooves, It has this on one side surface in the thickness direction, The inspection device, An analysis unit that generates three-dimensional shape data by analyzing the aforementioned three-dimensional image, A reference plane creation unit creates a reference plane based on the positional information of the tops of the first rib and the second rib, which are in contact with the confluence of the flow channels and included in the three-dimensional shape data, An offset plane creation unit creates an offset plane that is a predetermined distance away from the reference plane towards the bottom of the gas flow channel groove, A calculation unit that calculates the diameter of the inscribed circle of the channel confluence based on two-dimensional image data showing the offset plane, A fuel cell separator inspection system according to claim 1, comprising a control unit including

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

5. A warp correction process in which the warp of the separator is corrected using a warp correction jig, The inspection process includes inspecting the separator based on a three-dimensional image of the separator, which is captured while the separator is held by the warp correction jig and irradiated with measuring light. A method for inspecting a fuel cell separator, wherein the warping correction jig transmits the measurement light.

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