fuel cell

Abstract

This technology provides a way to prevent the outlet channel of the reaction gas from becoming blocked. [Solution] The fuel cell cell comprises a plate member having a membrane electrode gas diffusion layer assembly and a resin sheet holding the outer periphery of the membrane electrode gas diffusion layer assembly, a separator facing the plate member, a flow path section for circulating fluid between the plate member and the separator, and an outlet manifold for discharging fluid to the outside of the fuel cell cell. The flow path section has a main flow path section facing the membrane electrode gas diffusion layer assembly and a connecting flow path section connecting the main flow path section and the outlet manifold, the connecting flow path section facing the resin sheet. The connecting flow path section has a plurality of flow path grooves forming a plurality of outlet flow paths, and a hydrophilic portion and a hydrophobic portion formed in the area including the flow path grooves.

Description

Technical Field

[0001] This disclosure relates to fuel cell.

Background Art

[0002] Conventionally, a fuel cell having a membrane electrode gas diffusion layer assembly and a pair of separators sandwiching the membrane electrode gas diffusion layer assembly is known (Patent Document 1). This fuel cell has a gas flow path portion for allowing a reaction gas to flow between the membrane electrode gas diffusion layer assembly and the separator, and a manifold for allowing the reaction gas to flow through the fuel cell. The gas flow path portion has a main flow path portion facing the membrane electrode gas diffusion layer assembly and a connection flow path portion connecting the main flow path portion and the manifold. The connection flow path portion is provided with a plurality of flow path grooves forming a plurality of outlet flow paths.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In a fuel cell, water is generated in the process of supplying a reaction gas to a membrane electrode gas diffusion layer assembly and generating electricity by an electrochemical reaction. The water generated in the fuel cell during power generation passes through the outlet flow path together with the reaction gas not used for power generation and is discharged from the manifold to the outside of the fuel cell. In the conventional technology, the water generated in the fuel cell during power generation may be sucked into the flow path groove by capillary action, water may accumulate in the flow path groove, and there is a risk that the outlet flow path may be blocked.

Means for Solving the Problems

[0005] This disclosure can be realized in the following forms.

[0006] (1) According to one embodiment of the present disclosure, a fuel cell is provided. The fuel cell is provided, comprising a plate member having a membrane electrode gas diffusion layer assembly and a resin sheet holding the outer periphery of the membrane electrode gas diffusion layer assembly, a separator facing the plate member, a flow path section for circulating fluid between the plate member and the separator, and an outlet manifold for discharging the fluid outside the fuel cell, wherein the flow path section has a main flow path section facing the membrane electrode gas diffusion layer assembly and a connecting flow path section connecting the main flow path section and the outlet manifold, the connecting flow path section facing the resin sheet, and the connecting flow path section has a plurality of flow path grooves forming a plurality of outlet flow paths, and a hydrophilic portion and a hydrophobic portion formed in the area including the flow path grooves. According to this embodiment, water generated in the fuel cell during power generation can be concentrated and circulated in the outlet flow path formed by the outlet flow path grooves located on the hydrophilic portion. This makes it possible to secure the outlet flow path formed by the outlet flow path grooves located on the hydrophobic portion as a passage for fuel gas. Therefore, it is possible to prevent water generated in the fuel cell cell during power generation from accumulating in the outlet channel groove and blocking the outlet channel. (2) In the above configuration, the proportion of the water-repellent portion in the connecting channel may be 1 / 3 or less. With this configuration, it is possible to prevent a decrease in the water discharge rate due to the water-repellent portion occupying too large a proportion of the connecting channel. Also, by keeping the proportion of the water-repellent portion in the connecting channel small, it is possible to avoid water flowing from the outlet channel groove located on the hydrophilic portion to the outlet channel groove located on the water-repellent portion, thereby reducing the passage for the reaction gas. Thus, it is possible to more reliably suppress blockage of the outlet channel. (3) In the above configuration, the water-repellent portion may be positioned on the anti-gravity side of the hydrophilic portion in the installation position of the fuel cell. This configuration makes it easier to allow water accumulated on the gravity side of the fuel cell due to its own weight to flow into the outlet channel formed by the outlet channel groove located on the hydrophilic portion. This makes it possible to more reliably suppress blockage of the outlet channel. (4) In the above configuration, the flow path includes an anode flow path that flows fuel gas between the plate member and the anode separator as a separator, and the fuel cell cell may have at least the hydrophilic portion and the hydrophobic portion in the connecting flow path of the anode flow path. With this configuration, it is possible to suppress the blocking of the outlet flow path on the anode side, which is more prone to blockage than the cathode side. This disclosure can be implemented in various forms other than the fuel cell described above. For example, it can be implemented in the form of a fuel cell manufacturing method, a fuel cell stack formed by stacking multiple fuel cell cells, or a vehicle equipped with a fuel cell. [Brief explanation of the drawing]

[0007] [Figure 1] A diagram showing the schematic configuration of a fuel cell stack. [Figure 2] Exploded perspective view of a fuel cell. [Figure 3] Figure 1 illustrates the details of the outlet channel in the anode channel section. [Figure 4] Figure 2 illustrates the details of the outlet channel in the anode channel section. [Figure 5] Enlarged view of the outlet connection channel in the anode channel section. [Figure 6] A diagram illustrating an example of a method for forming hydrophilic and hydrophobic areas. [Modes for carrying out the invention]

[0008] A. Embodiments: Figure 1 shows a schematic configuration of a fuel cell stack 1. The fuel cell stack 1 generates electricity through an electrochemical reaction by receiving a fuel gas such as hydrogen and an oxidizer gas such as air. The fuel cell stack 1 has a stack structure in which multiple fuel cell cells 100 are stacked.

[0009] Figure 2 is an exploded perspective view of the fuel cell cell 100. The X direction is along the longitudinal direction of the fuel cell cell 100. The Y direction is along the short direction of the fuel cell cell 100. The Z direction is along the thickness direction of the fuel cell cell 100. In this embodiment, when the fuel cell stack 1 is installed on an object such as a vehicle, the +Y direction is the anti-gravity direction and the -Y direction is the gravity direction. The same applies to the figures and descriptions shown hereafter.

[0010] The fuel cell cell 100 comprises a plate member 10. The plate member 10 has a membrane electrode gas diffusion layer assembly 11 (MEGA) and a resin sheet 12.

[0011] The membrane electrode gas diffusion layer assembly 11 comprises a membrane electrode assembly (MEA). The membrane electrode assembly comprises an electrolyte membrane, an anode catalyst layer disposed on one side of the electrolyte membrane, and a cathode catalyst layer disposed on the other side of the electrolyte membrane. The electrolyte membrane selectively permeates specific ions. The anode catalyst layer catalyzes an electrochemical reaction on the anode side. The cathode catalyst layer catalyzes an electrochemical reaction on the cathode side. The membrane electrode gas diffusion layer assembly 11 further comprises an anode gas diffusion layer disposed opposite the anode catalyst layer and a cathode gas diffusion layer disposed opposite the cathode catalyst layer. The anode gas diffusion layer diffuses fuel gas and supplies it to the anode catalyst layer. The cathode gas diffusion layer diffuses oxidizer gas and supplies it to the cathode catalyst layer.

[0012] The resin sheet 12 is a rectangular frame. The resin sheet 12 has an opening 13 in the center. The outer periphery 11r of the membrane electrode gas diffusion layer assembly 11 is bonded to the opening 13 of the resin sheet 12 with adhesive. In this way, the resin sheet 12 holds the outer periphery 11r of the membrane electrode gas diffusion layer assembly 11.

[0013] The fuel cell cell 100 further includes an anode separator 20 and a cathode separator 30 that face the plate member 10 and sandwich the plate member 10. Each separator 20, 30 separates the plate member 10 from other fuel cell cells 100. Each separator 20, 30 has gas surfaces 20g, 30g and cooling surfaces 20c, 30c. The gas surfaces 20g, 30g are the surfaces that come into contact with the reaction gas. The cooling surfaces 20c, 30c are the surfaces that come into contact with the coolant and are the surfaces opposite to the gas surfaces 20g, 30g.

[0014] The resin sheet 12 and each separator 20, 30 each have manifolds 41-46 for fluid flow. The manifolds 41-46 are holes formed in the main bodies 21, 31 of the resin sheet 12 and each separator 20, 30. Each manifold 41-46 is formed at a position where it overlaps with the others in the stacking direction DL of the multiple fuel cell cells 100. This distributes the fuel gas to the anode side of the fuel cell cells 100, the oxidizer gas to the cathode side of the fuel cell cells 100, and the coolant for cooling the fuel cell cells 100 between adjacent fuel cell cells 100. Specifically, the fuel gas is supplied to the fuel gas inlet manifold 41. The fuel gas supplied to the fuel gas inlet manifold 41 is distributed to the anode side of each fuel cell cell 100 and flows through the anode flow path 50 formed between the plate member 10 and the gas surface 20g of the anode separator 20. Of the fuel gas distributed to the anode side, the fuel gas not used for power generation is discharged to the outside of the fuel cell stack 1 from the fuel gas outlet manifold 46. The fuel gas discharged to the outside of the fuel cell stack 1 is supplied again to the fuel gas inlet manifold 41. Oxidizer gas is supplied to the oxidizer gas inlet manifold 44. The oxidizer gas supplied to the oxidizer gas inlet manifold 44 is distributed to the cathode side of each fuel cell cell 100 and flows through the cathode flow path 60 formed between the plate member 10 and the gas surface 30g of the cathode separator 30. Of the oxidizer gas distributed to the cathode side, the oxidizer gas not used for power generation is discharged to the outside of the fuel cell stack 1 from the oxidizer gas outlet manifold 43. The oxidizer gas discharged to the outside of the fuel cell stack 1 is supplied again to the oxidizer gas inlet manifold 44. Coolant is supplied to the coolant inlet manifold 42. The coolant supplied to the coolant inlet manifold 42 is distributed between adjacent fuel cell cells 100 in the stacking direction DL, and flows through a coolant flow path (not shown) formed between the cooling surface 20c of the anode separator 20 and the cooling surface 30c of the cathode separator 30 of adjacent fuel cell cells 100. The coolant that has flowed between adjacent fuel cell cells 100 is discharged to the outside of the fuel cell stack 1 from the coolant outlet manifold 45.The coolant discharged outside the fuel cell stack 1 is supplied again to the coolant inlet manifold 42.

[0015] In the present embodiment, the outlet manifolds 43 and 46 for discharging the reaction gas outside the fuel cell 100 are arranged on the side in the direction of gravity relative to the inlet manifolds 41 and 44 for flowing the reaction gas into the fuel cell 100. Thereby, it becomes easier to discharge the water generated in the fuel cell 100 during power generation from the outlet manifolds 43 and 46, and it is possible to prevent the water generated in the fuel cell 100 during power generation from accumulating in the fuel cell 100.

[0016] The anode flow path portion 50 and the cathode flow path portion 60 each have a main flow path portion 51, 61, an inlet connection flow path portion 53, 63, and an outlet connection flow path portion 55, 65.

[0017] The main flow path portions 51 and 61 face the membrane electrode gas diffusion layer joined body 11. The main flow path portions 51 and 61 have a plurality of main flow paths 510 and 610 through which the reaction gas flows on the membrane electrode gas diffusion layer joined body 11. Each of the plurality of main flow paths 510 and 610 is formed by main flow path grooves 22 and 32 formed by bending each separator 20 and 30 by press working. The main flow path grooves 22 and 32 project from the main body portions 21 and 31 toward the cooling surfaces 20c and 30c from the gas surfaces 20g and 30g. In the present embodiment, a plurality of main flow path grooves 22 and 32 are formed in parallel at a predetermined interval. Thereby, the reaction gas travels straight through the main flow paths 510 and 610. That is, in the present embodiment, the main flow paths 510 and 610 are linear straight flow paths.

[0018] The outlet connection channel sections 55 and 65 connect the main channel sections 51 and 61 to the outlet manifolds 43 and 46. The outlet connection channel sections 55 and 65 face the resin sheet 12. The outlet connection channel sections 55 and 65 have a plurality of outlet channels 550 and 650 that allow fluid to flow from the main channel sections 51 and 61 to the outlet manifolds 43 and 46. The outlet channels 550 and 650 are formed by the slits 15 in the resin sheet 12 and the outlet channel grooves 25 and 35 of the separator 20, one end of which is connected to the slits 15 and the other end of which is connected to the outlet manifolds 43 and 46.

[0019] Figure 3 is the first diagram illustrating the details of the outlet channel 550 in the anode channel section 50. Figure 3 shows the III-III cross-section in Figure 2. Figure 4 is the second diagram illustrating the details of the outlet channel 550 in the anode channel section 50. Figure 4 shows the IV-IV cross-section in Figure 2. As shown in Figure 2, the resin sheet 12 further has a plurality of perforated slits 15 between the membrane electrode gas diffusion layer assembly 11 and the fuel gas outlet manifold 46. As a result, the fluid that has flowed through the main channel 510 of the anode channel section 50 flows into the outlet channel 550 through the slits 15 in the resin sheet 12 formed between the membrane electrode gas diffusion layer assembly 11 and the fuel gas outlet manifold 46. At this time, as shown in Figure 3, each surface 10a, 10c of the resin sheet 12 is in contact with the gas surfaces 20g, 30g of each separator 20, 30, except for the parts where the slits 15 are formed. Therefore, the fluid flowing in from the slit 15 flows through the space surrounded by the resin sheet 12 and the gas surfaces 20g and 30g of each separator 20 and 30. Furthermore, as shown in Figure 4, the anode separator 20 has a plurality of outlet flow channel grooves 25 formed by bending the anode separator 20 by press working between the slit 15 and the fuel gas outlet manifold 46. These outlet flow channel grooves 25 protrude from the main body 21 from the gas surface 20g toward the cooling surface 20c. Since the outlet flow channel grooves 25 are connected to the slit 15, the fluid that has flowed through the space surrounded by the resin sheet 12 and the gas surfaces 20g and 30g of each separator 20 and 30 flows through the space surrounded by the anode-facing surface 10a of the resin sheet 12 and the outlet flow channel grooves 25 of the anode separator 20. Since the outlet channel groove 25 is connected to the fuel gas outlet manifold 46, the fluid that flows through the space enclosed by the anode-facing surface 10a of the resin sheet 12 and the outlet channel groove 25 of the anode separator 20 is discharged outside the fuel cell cell 100 from the fuel gas outlet manifold 46. The configuration of the outlet channel 650 in the cathode channel section 60 is the same as the configuration of the outlet channel 550 in the anode channel section 50.

[0020] As shown in FIG. 2, in the present embodiment, a plurality of the above-described outlet flow paths 550 and 650 are formed in parallel at a predetermined interval between the membrane electrode gas diffusion layer joined body 11 and the outlet manifolds 43 and 46. Thereby, the reaction gas flows through the comb-shaped narrow outlet flow paths 550 and 650 formed by the slits 15 and 16 of the resin sheet 12 and the outlet flow path grooves 25 and 35 of the respective separators 20 and 30, and is discharged from the outlet manifolds 43 and 46.

[0021] The inlet connection flow path portions 53 and 63 connect the main flow path portions 51 and 61 and the inlet manifolds 41 and 44. The inlet connection flow path portions 53 and 63 face the resin sheet 12. The inlet connection flow path portions 53 and 63 have a plurality of inlet flow paths 530 and 630 that allow fluid to flow from the inlet manifolds 41 and 44 toward the main flow path portions 51 and 61. Similar to the outlet flow paths 550 and 650, the inlet flow paths 530 and 630 are formed by the slits 17 and 18 of the resin sheet 12 and the inlet flow path grooves 23 and 33 of the separators 20 and 30, one end of which is connected to the slits 17 and 18 and the other end of which is connected to the inlet manifolds 41 and 44.

[0022] Thus, in the connection flow path portions 53, 55, 63, and 65, by providing the slits 15 to 18 in the resin sheet 12 and causing the portions between the slits 15 to 18 to function as girders, it is possible to suppress the resin sheet 12 from bending. Thereby, the inlet flow paths 530 and 630 and the outlet flow paths 550 and 650 can be ensured.

[0023] However, in the fuel cell cell 100, water is generated during the process of generating electricity through an electrochemical reaction when a reaction gas is supplied to the membrane electrode gas diffusion layer assembly 11. The water generated in the fuel cell cell 100 during power generation passes through the outlet channels 550 and 650 along with the reaction gas that was not used for power generation, and is discharged outside the fuel cell cell 100 from the outlet manifolds 43 and 46. As a result, water generated in the fuel cell cell 100 during power generation may be drawn into the outlet channel grooves 25 and 35 by capillary action, causing water to accumulate in the outlet channel grooves 25 and 35, and potentially blocking the outlet channels 550 and 650 formed by the outlet channel grooves 25 and 35. Furthermore, because water molecules attract each other, the water accumulated in the outlet channel grooves 25 and 35 attracts water present in the surrounding area, increasing the likelihood of blockage of the outlet channels 550 and 650. If the outlet passages 550 and 650 become blocked, it may not be possible to discharge water generated within the fuel cell cell 100 during power generation or reaction gases not used for power generation from the fuel cell cell 100 to the outside of the fuel cell cell 100. If water and reaction gases cannot be discharged to the outside of the fuel cell cell 100, it may not be possible to continue power generation by the fuel cell cell 100, or it may not be possible to restart power generation by the fuel cell cell 100 after power generation has stopped.

[0024] Therefore, when power generation by the fuel cell cell 100 is stopped, scavenging gas is supplied to the outlet channels 550 and 650 to perform scavenging treatment, which discharges water accumulated in the outlet channel grooves 25 and 35 using the gas pressure of the scavenging gas. However, if a large amount of water accumulates in the outlet channel grooves 25 and 35, the scavenging treatment may not be able to resolve the blockage of the outlet channels 550 and 650. In addition, depending on the installation environment and usage conditions of the fuel cell cell 100, such as when starting the fuel cell cell 100 at sub-zero temperatures, the water accumulated in the outlet channel grooves 25 and 35 may freeze, completely blocking the outlet channels 550 and 650. If the water accumulated in the outlet channel grooves 25 and 35 freezes and completely blocks the outlet channels 550 and 650, it is difficult to resolve the blockage of the outlet channels 550 and 650 by scavenging treatment.

[0025] To address the above-mentioned problems, one possible method is to make the outlet connection channel sections 55 and 65 water-repellent to prevent water from accumulating in the outlet channel grooves 25 and 35. However, if the entire outlet connection channel sections 55 and 65 are made water-repellent, water will have difficulty flowing to the outlet channel grooves 25 and 35, and there is a risk that water will accumulate inside the fuel cell cell 100. Therefore, the inventors of the present invention have come up with the idea of ​​making a part of the outlet connection channel sections 55 and 65 water-repellent to create a difference in affinity with water, i.e., the degree of wetting, thereby preventing water from accumulating in the outlet channel grooves 25 and 35 and blocking the outlet channels 550 and 650.

[0026] Figure 5 is an enlarged view of the outlet connection channel section 55 in the anode channel section 50. Figure 5 shows an enlarged view of region R in Figure 2. The outlet connection channel section 55 has a hydrophilic portion 551 and a hydrophobic portion 552 that has a lower affinity for water than the hydrophilic portion 551, within the area including the outlet channel groove 25. In Figure 5, the hydrophilic portion 551 is shown with dot hatching. The hydrophobic portion 552 is shown with diagonal hatching. Each outlet channel groove 25 is located either on the hydrophilic portion 551 or on the hydrophobic portion 552. In this way, water can be concentrated and flowed into the outlet channel 550a formed by the outlet channel groove 25a located on the hydrophilic portion 551. By intentionally providing a region in the outlet connection channel section 55 where water accumulates, water can be prevented from accumulating in the outlet channel 550b formed by the outlet channel groove 25b located on the hydrophobic portion 552, thereby securing a passage for fuel gas. This prevents water from accumulating in all the outlet channel grooves 25 in the outlet connection channel section 55, thus preventing the outlet channel 550 from becoming blocked. The affinity for water can be expressed, for example, by the contact angle, which is an evaluation index for wettability between a solid surface and a liquid. In this case, the contact angle of the water-repellent section 552 is larger than the contact angle of the hydrophilic section 551.

[0027] Here, the smaller the flow rate of the reaction gas, the more difficult it is for the water accumulated in the outlet channel grooves 25 and 35 to be discharged by the gas pressure of the reaction gas, and the greater the possibility that the outlet channels 550 and 650 will become blocked. Generally, in a fuel cell cell 100, the flow rate of the fuel gas flowing through the anode channel section 50 is smaller than the flow rate of the oxidizer gas flowing through the cathode channel section 60. Therefore, the outlet channel 550 in the anode channel section 50 is more prone to blockage than the outlet channel 650 in the cathode channel section 60. In this embodiment, the fuel cell cell 100 has a hydrophilic portion 551 and a hydrophobic portion 552 in the outlet connection channel section 55 of the anode channel section 50. In this way, it is possible to suppress the blockage of the anode-side outlet channel 550, which is more prone to blockage than the cathode side.

[0028] Furthermore, the larger the proportion of the water-repellent portion 552 in the outlet connection channel section 55, the more difficult it may be for water to flow to the outlet channel groove 25 side. This can reduce the water discharge rate, potentially preventing sufficient discharge of water generated within the fuel cell cell 100 during power generation. On the other hand, the smaller the proportion of the water-repellent portion 552 in the outlet connection channel section 55, the more likely it is that water will flow from the outlet channel groove 25 located on the hydrophilic portion 551 to the outlet channel groove 25b located on the water-repellent portion 552. In particular, when the fuel cell cell 100 is used in low-temperature environments such as below freezing, the lower the temperature in the environment where the fuel cell cell 100 is installed, the greater the volume of water, and the more likely it is that water will flow to the outlet channel groove 25b located on the water-repellent portion 552. This can cause water to accumulate in the outlet channel groove 25 located on the water-repellent portion 552, reducing the passage for fuel gas and potentially making it difficult to adequately prevent blockage of the outlet channels 550 and 650. Therefore, in this embodiment, the proportion occupied by the water-repellent portion 552 in the outlet connection channel 55 is 1 / 3 or less. In other words, in each part of the outlet connection channel 55, the height H2 of the water-repellent portion 552 relative to the height H1 of the outlet connection channel 55 is 1 / 3 or less. In this way, even if the fuel cell cell 100 is affected by various disturbances such as the installation environment, usage conditions, and the amount of water produced according to the flow rate of the reaction gas, it is possible to suppress the blockage of the outlet channel 550.

[0029] Furthermore, the water generated in the fuel cell cell 100 during power generation accumulates on the gravity side of the fuel cell cell 100 due to its own weight. Therefore, in this embodiment, the water-repellent portion 552 is positioned on the anti-gravity side of the hydrophilic portion 551 in the installation position of the fuel cell cell 100. In this way, the water accumulated on the gravity side of the fuel cell cell 100 due to its own weight can be easily allowed to flow into the outlet channel 550 formed by the outlet channel groove 25 located on the hydrophilic portion 551. This makes it possible to more reliably suppress blockage of the outlet channel 550.

[0030] As described above using Figures 2 to 4, the outlet channels 550 and 650 are formed in the space surrounded by the respective surfaces 10a and 10c of the resin sheet 12, including the slits 15 and 16, and the gas surfaces 20g and 30g of the respective separators 20 and 30, including the outlet channel grooves 25 and 35. Therefore, the hydrophilic portion 551 and the water-repellent portion 552 only need to be formed on at least one of the respective surfaces 10a and 10c of the resin sheet 12 and the gas surfaces 20g and 30g of the separators 20 and 30.

[0031] Figure 6 is a diagram illustrating an example of a method for forming a hydrophilic portion 551 and a hydrophobic portion 552. For example, if a hydrophobic member having water-repellent properties is prepared as the base material for the anode separator 20, and the hydrophobic member is processed to form a hydrophilic portion 551 and a hydrophobic portion 552 on the gas surface 20g of the anode separator 20, the following steps are performed. In this case, first, a mask member 90 is attached to the hydrophobic member, with the portion of the anode flow channel 50 that is not open except for the portion where the hydrophobic portion 552 is to be formed. In Figure 6, the mask member 90 is shown with dot hatching. Next, with the portion of the anode flow channel 50 where the hydrophobic portion 552 is to be formed covered by the mask member 90, a hydrophilic treatment is applied to the surface of the hydrophobic member. Hydrophilic treatment is a process that enhances the hydrophilicity of the surface of an object to be treated by roughening the surface of the object to be treated to create irregularities across the entire surface, or by replacing the terminal groups of molecules constituting the surface of the object with hydrophilic functional groups such as hydroxyl groups. Hydrophilic treatment is, for example, plasma treatment. Next, the mask member 90 is removed from the water-repellent member. As a result, the hydrophilic portion 551 can be formed in the portion of the gas surface 20g of the anode separator 20 by applying the hydrophilic treatment. The portion of the gas surface 20g of the anode separator 20 to be formed of the water-repellent portion 552 is not subjected to the hydrophilic treatment, so the water-repellent portion 552 can be formed without performing a water-repellent treatment to enhance the water repellency of the surface of the object to be treated. In this way, both the hydrophilic portion 551 and the water-repellent portion 552 can be formed simultaneously in the outlet connection channel 55. This simplifies the manufacturing process of the fuel cell cell 100. Furthermore, by changing the shape of the mask member 90, the proportion occupied by the water-repellent portion 552 and the arrangement of the water-repellent portion 552 in the outlet connection channel portion 55 can be easily changed.

[0032] According to the above embodiment, the outlet connection channel section 55 in the anode channel section 50 has a hydrophilic section 551 and a hydrophobic section 552 in the area including the outlet channel groove 25 that forms the outlet channel 550. In this way, the water generated in the fuel cell cell 100 during power generation can be concentrated and flowed through the outlet channel 550a formed by the outlet channel groove 25a located on the hydrophilic section 551. This ensures that the outlet channel 550b formed by the outlet channel groove 25b located on the hydrophobic section 552 is secured as a passage for fuel gas. Therefore, it is possible to prevent water generated in the fuel cell cell 100 during power generation from accumulating in the outlet channel groove 25 and blocking the outlet channel 550.

[0033] Furthermore, according to the above embodiment, it is possible to suppress the accumulation of water generated in the fuel cell cell 100 during power generation in the outlet channel groove 25, which would otherwise block the outlet channel 550. This makes it possible to eliminate the need for scavenging, reduce the number of scavenging treatments, or shorten the time required for scavenging treatment.

[0034] B. Other embodiments: (B1) As shown in Figure 2, the fuel cell cell 100 may have hydrophilic portions 551, 651 and hydrophobic portions 552, 652 in the area including the outlet channel grooves 25, 35 in both the outlet connection channel portion 55 of the anode channel portion 50 and the outlet connection channel portion 65 of the cathode channel portion 60. With this configuration, it is possible to suppress the blockage of the outlet channels 550, 650 on either the anode side or the cathode side. This reduces the possibility that water generated in the fuel cell cell 100 during power generation and reaction gases not used for power generation cannot be discharged from the fuel cell cell 100 to the outside of the fuel cell cell 100. Therefore, it is possible to avoid situations in which power generation by the fuel cell cell 100 cannot be continued or in which power generation of the fuel cell cell 100 cannot be restarted after power generation has stopped.

[0035] (B2) The fuel cell cell 100 may have a hydrophilic portion 551 and a hydrophobic portion 552 in the outlet connection channel 55 of the anode channel 50, but may have a hydrophilic portion 651 and a hydrophobic portion 652 in the outlet connection channel 65 of the cathode channel 60. In this configuration, it is possible to suppress the blocking of the outlet channel 650 on the cathode side.

[0036] (B3) Depending on various conditions such as the flow rate of the reaction gas and the dimensions of the outlet manifolds 43 and 46, the proportion occupied by the water-repellent portion 552 and 652 in the outlet connection flow path section 55 and 65 may be greater than 1 / 3. Even in this configuration, blockage of the outlet flow path 550 can be suppressed.

[0037] (B4) In the installation orientation of the fuel cell cell 100, it is not essential that the water-repellent parts 552 and 652 are positioned on the anti-gravity side of the hydrophilic parts 551 and 651. For example, in the installation orientation of the fuel cell cell 100, where the +X direction is the direction of gravity and the -X direction is the direction of anti-gravity, the outlet manifolds 43 and 46 are positioned on the gravity side of the outlet connection flow channels 55 and 65, the following may be used. In this case, the hydrophilic parts 551 and 651 and the water-repellent parts 552 and 652 may be positioned at the same height in the direction of gravity in the installation orientation of the fuel cell cell 100. Even in this configuration, it is possible to suppress the blockage of the outlet flow channel 550.

[0038] (B5) The method for forming the hydrophilic portions 551, 651 and the hydrophobic portions 552, 652 is not limited to the above. For example, a hydrophilic member having hydrophilic properties may be prepared as the base material for the separators 20, 30, and a hydrophobic treatment may be applied to a part of the hydrophilic member while the mask member 90 is attached, thereby forming the hydrophilic portions 551, 651 and the hydrophobic portions 552, 652 on the separators 20, 30. The hydrophobic treatment is a treatment that reduces the hydrophilicity of the surface of the object to be treated and increases its hydrophobicity, for example, by coating the surface of the object to be treated with a water-repellent material such as Teflon (registered trademark). In this configuration as well, the hydrophilic portions 551, 651 and the hydrophobic portions 552, 652 can be formed simultaneously on the outlet connection channel portions 55, 65. This simplifies the manufacturing process of the fuel cell cell 100. Furthermore, by changing the shape of the mask member 90, the proportion occupied by the water-repellent parts 552 and 652 in the outlet connection channel sections 55 and 65, and the arrangement of the water-repellent parts 552 and 652 can be easily changed.

[0039] (B6) The method for forming the hydrophilic portions 551 and 651 is not limited to the above. The hydrophilic treatment may be a treatment that enhances the hydrophilicity of the surface of the object to be treated by coating the surface of the object with a hydrophilic material such as silicon dioxide (SiO2) or titanium dioxide (TiO2). In this form as well, the hydrophilic portions 551 and 651 can be formed on the separators 20 and 30.

[0040] (B7) In each of the above embodiments, hydrophilic portions 551, 651 and hydrophobic portions 552, 652 were formed on the separators 20, 30 by applying either a hydrophilic treatment or a hydrophobic treatment to the substrate surface of the separators 20, 30, which is contrary to the properties of the substrate of the separators 20, 30. Alternatively, hydrophilic portions 551, 651 and hydrophobic portions 552, 652 may be formed on the separators 20, 30 by applying a hydrophilic treatment to the portion of the substrate surface where hydrophilic portions 551, 651 are to be formed, and a hydrophobic treatment to the portion where hydrophobic portions 552, 652 are to be formed. In this form as well, hydrophilic portions 551, 651 and hydrophobic portions 552, 652 can be formed on the separators 20, 30.

[0041] (B8) Similar to the embodiments described above, hydrophilic and hydrophobic treatments may be applied to each surface 10a, 10c of the resin sheet 12 that constitute the outlet channels 550, 650, thereby forming hydrophilic portions 551, 651 and hydrophobic portions 552, 652 on the resin sheet 12. Furthermore, hydrophilic portions 551, 651 and hydrophobic portions 552, 652 may be formed on both each surface 10a, 10c of the resin sheet 12 and the gas surfaces 20g, 30g of the separators 20, 30. In this configuration, the water generated in the fuel cell cell 100 during power generation can be further concentrated and circulated through the outlet channel 550a formed by the outlet channel groove 25a located on the hydrophilic portion 551. This makes it possible to more reliably suppress blockage of the outlet channel 550.

[0042] (B9) The configuration of the fuel cell cell 100 is not limited to the above. The fuel cell cell 100 may, for example, include meandering main flow channels 22, 32. In other words, the main flow channels 510, 610 may be serpentine flow channels through which the reaction gas flows in a meandering manner. Even in such a configuration, blockage of the outlet flow channel 550 can be suppressed.

[0043] This disclosure is not limited to the embodiments described above, and can be implemented in various configurations without departing from its spirit. For example, the technical features of the embodiments corresponding to the technical features in each form described in the summary of the invention can be replaced or combined as appropriate in order to solve some or all of the above-described problems, or to achieve some or all of the above-described effects. Furthermore, if a technical feature is not described as essential in this specification, it can be deleted as appropriate. [Explanation of symbols]

[0044] 1…Fuel cell stack, 10…Plate member, 10a…Anode-facing surface, 10c…Cathode-facing surface, 11…Membrane electrode gas diffusion layer assembly, 11r…Outer periphery, 12…Resin sheet, 13…Opening, 15-18…Slit, 20…Anode separator, 20c,30c…Cooling surface, 20g,30g…Gas surface, 21,31…Main body, 22,32…Main flow channel groove, 23,33…Inlet flow channel groove, 25,25a,25b,35…Outlet flow channel groove, 30…Cathode separator, 41…Fuel gas inlet manifold, 42…Coolant inlet manifold, 43…Oxidizer gas outlet manifold 44...Oxidizer gas inlet manifold, 45...Coolant outlet manifold, 46...Fuel gas outlet manifold, 50...Anode flow path section, 51,61...Main flow path section, 53,63...Inlet connection flow path section, 55,65...Outlet connection flow path section, 60...Cathode flow path section, 90...Mask member, 100...Fuel cell cell, 510,610...Main flow path, 530,630...Inlet flow path, 550,550a,550b,650...Outlet flow path, 551,651...Hydrophilic section, 552,652...Hydrophilic section, DL...Layering direction, H1...Height of outlet connection flow path section, H2...Height of hydrophobic section, R...Region

Claims

1. It is a fuel cell cell, A plate member having a membrane electrode gas diffusion layer assembly and a resin sheet that holds the outer periphery of the membrane electrode gas diffusion layer assembly, A separator facing the aforementioned plate member, A fluid passage section for circulating fluid between the plate member and the separator, The fuel cell cell comprises an outlet manifold for discharging the fluid outside the fuel cell, The aforementioned flow channel section is The main channel portion facing the aforementioned membrane electrode gas diffusion layer assembly, A connecting channel section that connects the main channel section and the outlet manifold, comprising a connecting channel section facing the resin sheet, The aforementioned connecting channel section is Multiple channel grooves that form multiple outlet channels, A fuel cell having a hydrophilic portion and a hydrophobic portion formed in the area including the aforementioned flow channel groove.

2. A fuel cell cell according to claim 1, A fuel cell in which the proportion of the water-repellent portion in the connecting channel portion is 1 / 3 or less.

3. A fuel cell cell according to claim 1, The water-repellent portion is positioned on the anti-gravity side of the hydrophilic portion in the installation orientation of the fuel cell.

4. A fuel cell cell according to claim 1, The flow path section includes an anode flow path section that allows fuel gas to flow between the plate member and the anode separator, The fuel cell has at least the hydrophilic portion and the hydrophobic portion in the connecting channel portion of the anode channel portion.

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