Fuel cell separators and fuel cell cells

Abstract

To effectively improve power generation efficiency. [Solution] A flow path 18 is formed between the main body 15 and the membrane electrode gas diffusion layer assembly of the separator 14 of the fuel cell cell. The main body 15 is divided into central regions AC1, AC2, AC3 and turn regions AT1, AT2. The central regions extend along the long side of the main body 15 and are arranged in the direction of the short side. The turn regions extend in the direction of the short side and are located corresponding to the longitudinal ends of adjacent central regions. The flow path 18 is formed by a central flow path section 18a that passes through a plurality of central regions in the longitudinal direction, and a turn flow path section 18b that passes through the turn regions and connects the central flow path sections 18a of adjacent central regions. The flow path 18 is formed between a plurality of ribs 19 in the main body 15. A plurality of central flow path sections 18a are formed in the central regions, and a plurality of ribs 19 are formed so that the turn flow path section 18b in the turn regions is connected to the plurality of central flow path sections 18a in the central regions.

Description

Technical Field

[0001] The present disclosure relates to a separator of a fuel cell and a fuel cell.

Background Art

[0002] As shown in Patent Document 1, a cell stack of a fuel cell is formed by stacking fuel cells in the thickness direction. A fuel cell is formed by sandwiching a membrane electrode gas diffusion layer assembly from both sides in the thickness direction with a square plate-shaped separator. The separator of the fuel cell includes a main body in which a plurality of ribs extending in parallel are formed. The ribs contact the membrane electrode gas diffusion layer assembly by protruding from the main body. The main body forms a flow path for flowing gas between the membrane electrode gas diffusion layer assembly and between the plurality of ribs.

[0003] Fuel gas such as hydrogen flows through the flow path between the separator located on the anode side of both sides in the thickness direction of the membrane electrode gas diffusion layer assembly and the anode side of the membrane electrode gas diffusion layer assembly. Also, oxidizing gas such as air flows through the flow path between the separator located on the cathode side of both sides in the thickness direction of the membrane electrode gas diffusion layer assembly and the cathode side of the membrane electrode gas diffusion layer assembly. And in the fuel cell, power generation is performed based on the reaction of the fuel gas and the oxidizing gas in the membrane electrode gas diffusion layer assembly.

[0004] The main body of the separator is divided into a central region and a turn region. The central region extends along one side of the main body and is arranged in the extending direction of another side intersecting the above one side of the main body. The turn region extends along the above another side and is positioned corresponding to the longitudinal ends of adjacent central regions. The flow path is formed by a central flow path portion that passes through each of the plurality of central regions in the longitudinal direction, and a turn flow path portion that passes through the turn region and connects the central flow path portions of adjacent central regions. A plurality of flow paths composed of such central flow path portions and turn flow path portions are formed in parallel. That is, a plurality of ribs are formed on the main body so that a plurality of flow paths are formed in such a manner.

[0005] In a fuel cell cell, the anode-side separator and the cathode-side separator are identical, just reversed. In this case, the direction of the fuel gas flow through the central channel of the anode-side channel in the membrane electrode gas diffusion layer assembly is opposite to the direction of the oxidizing gas flow through the central channel of the cathode-side channel in the membrane electrode gas diffusion layer assembly. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2005-190795 [Overview of the Initiative] [Problems that the invention aims to solve]

[0007] Incidentally, in the membrane electrode gas diffusion layer assembly of a fuel cell cell, the power generation efficiency is best when the flow direction of the fuel gas flowing through the above-mentioned channel on the anode side and the flow direction of the oxidizing gas flowing through the above-mentioned channel on the cathode side are opposite. For this reason, it is preferable to make the central channel portion of the above-mentioned channel as long as possible in order to improve the power generation efficiency of the fuel cell cell.

[0008] The separator body in Patent Document 1 forms multiple turn channel sections connected to multiple central channel sections of the above-mentioned flow path. Therefore, in order to lengthen the central channel section of the above-mentioned flow path, it is conceivable to shorten the overall width of the multiple turn channel sections in the direction in which the central channel section extends.

[0009] However, since the number of turn channel sections is the same as the number of central channel sections within a single central region, there is a limit to how much the overall width of the multiple turn channel sections can be shortened in the direction in which the central channel section extends. Due to this difficulty in lengthening the central channel section of the above-mentioned flow path, it has been difficult to effectively improve the power generation efficiency of fuel cell cells. [Means for solving the problem]

[0010] The following describes the means and effects of solving the above problems. The fuel cell separator that solves the above problems comprises a rectangular plate-shaped body that can be positioned on both sides of the membrane electrode gas diffusion layer assembly in the thickness direction. The body forms a flow path for gas to flow between itself and the membrane electrode gas diffusion layer assembly. The body is divided into a central region and a turn region. The central region extends along one side of the body and is aligned in the direction of the other side that intersects with the aforementioned side. The turn region extends along the other side and is positioned corresponding to the longitudinal ends of adjacent central regions. The flow path is formed by a central flow path section that passes through multiple central regions in the longitudinal direction, and a turn flow path section that passes through the turn region and connects the central flow paths of adjacent central regions. Multiple ribs are formed on the body that protrude toward the membrane electrode gas diffusion layer assembly and come into contact with it. The flow path is formed between the multiple ribs. Furthermore, multiple central flow channels are formed within the central region, and multiple ribs are formed on the main body such that the turn-type flow channels within the turn-type region connect to the multiple central flow channels within the central region.

[0011] According to the above configuration, since the turn channel section within the turn region is connected to multiple central channel sections within the central region, the number of turn channel sections within the turn region can be reduced to less than the number of central channel sections within the central region. Therefore, the overall width of the turn channel section in the direction in which the central channel section extends, in other words, the width of the turn region can be shortened. As the width of the turn region is shortened in this way, the central channel section and the central channel section can be lengthened. By sandwiching the membrane electrode gas diffusion layer assembly from the anode side and the cathode side with a separator with its front and back sides reversed, the gas flow in the channel on the anode side and the gas flow in the channel on the cathode side become as follows: That is, the direction of gas flow in the central channel section of the channel on the anode side and the direction of gas flow in the central channel section of the channel on the cathode side are opposite. By flowing gas in opposite directions in the central channel section on the anode side and the central channel section on the cathode side in this way, the power generation efficiency of the membrane electrode gas diffusion layer assembly is improved. Furthermore, as described above, the length of the central channel section can be lengthened, thus effectively improving the power generation efficiency.

[0012] The fuel cell cell that solves the above problems is sandwiched on both sides in the thickness direction by two rectangular plate-shaped separators, which are inverted versions of the membrane electrode gas diffusion layer assembly. A flow path for gas is formed between the separators and the membrane electrode gas diffusion layer assembly. The separator is divided into a central region and a turn region. The central region extends along one side of the separator and is aligned in the direction of the other side of the separator that intersects with the aforementioned side. The turn region extends along the other side and is located corresponding to the longitudinal ends of adjacent central regions. The flow path is formed by a central flow path section that passes through multiple central regions in the longitudinal direction, and a turn flow path section that passes through the turn region and connects the central flow paths of adjacent central regions. Multiple ribs are formed on the separator that protrude toward the membrane electrode gas diffusion layer assembly and come into contact with it. The flow path is formed between the multiple ribs. Furthermore, multiple central flow channels are formed within the central region, and multiple ribs are formed on the separator so that the turn flow channels within the turn region connect to the multiple central flow channels within the central region.

[0013] According to the above configuration, since the turn channel section within the turn region is connected to multiple central channel sections within the central region, the number of turn channel sections within the turn region can be reduced to less than the number of central channel sections within the central region. Therefore, the overall width of the turn channel section in the direction in which the central channel section extends can be shortened. As the overall width of the turn channel section is shortened in this way, the central channel section can be lengthened. By sandwiching the membrane electrode gas diffusion layer assembly from the anode side and the cathode side with a separator with its front and back sides reversed, the gas flow in the channel on the anode side and the gas flow in the channel on the cathode side become as follows: That is, the direction of gas flow in the central channel section of the channel on the anode side and the direction of gas flow in the central channel section of the channel on the cathode side are opposite. By flowing gas in opposite directions in the central channel section on the anode side and the central channel section on the cathode side in this way, the power generation efficiency of the membrane electrode gas diffusion layer assembly is improved. Furthermore, as described above, the length of the central channel section can be lengthened, thus effectively improving the power generation efficiency. [Brief explanation of the drawing]

[0014] [Figure 1] This is an exploded perspective view showing a fuel cell. [Figure 2] This is a cross-sectional view showing a cell stack formed by stacking fuel cell cells, as shown in Figure 1. [Figure 3] This is a plan view showing the main body of the separator in Figure 1 as seen from the front side. [Figure 4] This is a plan view showing the main body of the separator in Figure 1 as seen from the back side. [Figure 5] Figure 1 is a plan view showing the anode-side separator and cathode-side separator in a fuel cell cell superimposed. [Figure 6] Figures 3 and 4 are schematic diagrams showing cross-sections of the turn channel section and its surrounding area within the turn region of the separator. [Figure 7] This is a plan view showing a comparative example of a separator. [Modes for carrying out the invention]

[0015] Hereinafter, an embodiment of a fuel cell separator and a fuel cell cell will be described with reference to Figures 1 to 7. Figure 1 shows a fuel cell cell 11 for forming a fuel cell stack. The fuel cell cell 11 comprises a resin plate 12, a membrane electrode gas diffusion layer assembly 13, and a separator 14. The resin plate 12 is formed in the shape of a rectangular frame. The outer edge of the membrane electrode gas diffusion layer assembly 13 is joined to the resin plate 12. The resin plate 12 and the membrane electrode gas diffusion layer assembly 13 are sandwiched between separators 14 positioned on both sides in the thickness direction. The separator 14 is formed in the shape of a rectangular plate corresponding to the outer shape of the resin plate 12.

[0016] The fuel cell stack is formed by stacking the above-described fuel cells 11 in the thickness direction. A plurality of holes 16 are formed in the resin plate 12 and the separator 14 of the fuel cell 11. Among the plurality of holes 16, three are located at one end in the long side direction of the fuel cell 11, and the other three are located at the other end in the long side direction of the fuel cell 11. The plurality of holes 16 are grouped in pairs of two, one at one end and the other at the other end in the long side direction of the fuel cell 11. Each pair of holes 16 is used for flowing fluids such as fuel gas like hydrogen, oxidizing gas like air, and refrigerant like cooling water.

[0017] The separator 14 includes a main body 15 formed in a rectangular plate shape by a metal such as stainless steel, titanium, and aluminum. A plurality of ribs 19 are formed in parallel on the main body 15. A seal member 17 is disposed between the main body 15 of the separator 14 and the resin plate 12. The seal member 17 can be disposed on both the front and back surfaces in the thickness direction of the resin plate 12.

[0018] The seal member 17 disposed on the surface side of the resin plate 12 surrounds a pair of two holes 16 located on one of the two diagonals of the resin plate 12 and the separator 14 and the anode side of the membrane electrode gas diffusion layer assembly 13. The seal member 17 also surrounds the plurality of ribs 19 on the separator 14 located on the anode side. And between the plurality of ribs 19 on this separator 14, a flow path 18 for flowing fuel gas is formed. Fuel gas can flow through this flow path 18 via a pair of two holes 16.

[0019] The seal member 17 disposed on the back side of the resin plate 12 surrounds a pair of two holes 16 located on the other diagonal line of the above-mentioned two diagonal lines in the resin plate 12 and the separator 14, and the cathode side of the membrane electrode gas diffusion layer laminate 13. The seal member 17 also surrounds a plurality of ribs 19 in the separator 14 located on the anode side. And between the plurality of ribs 19 in this separator 14, a flow path 18 for flowing an oxidizing gas is formed. Oxidizing gas can flow through this flow path 18 via a pair of the holes 16.

[0020] In the fuel cell stack of the fuel cell 11, the separator 14 on the anode side in a predetermined fuel cell 11 and the separator 14 on the cathode side of another fuel cell 11 different from the above fuel cell 11 are adjacent to each other. The adjacent separators 14 are welded to each other so as to go around the periphery of two sets of holes 16 located on the diagonal line of the separator 14, and are not welded to each other around the hole 16 located at the center in the short side direction of the separator 14. Also, the outer edges of the adjacent separators 14 are welded. Thereby, it is possible to flow a refrigerant through the hole 16 located at the center in the short side direction of the separator 14 between the adjacent separators 14.

[0021] In the fuel cell stack of the fuel cell 11, fuel gas is flowed to the anode side of the membrane electrode gas diffusion layer laminate 13, and oxidizing gas is flowed to the cathode side of the membrane electrode gas diffusion layer laminate 13. Thus, when fuel gas and oxidizing gas are flowed to the anode side and the cathode side of the membrane electrode gas diffusion layer laminate 13, power generation is performed based on the reaction of these fuel gas and oxidizing gas in the membrane electrode gas diffusion layer laminate 13. In order to suppress the temperature rise of the fuel cell stack due to such power generation, a refrigerant is flowed between the adjacent separators 14 of the fuel cells 11 as described above. The fuel cell stack is cooled by this refrigerant.

[0022] As shown in Figure 2, the membrane electrode gas diffusion layer assembly 13 of the fuel cell cell 11 comprises an electrolyte layer 20, a cathode electrode layer 21, an anode electrode layer 22, and a gas diffusion layer 23. The electrolyte layer 20 is formed, for example, from a solid polymer membrane. The cathode electrode layer 21 is bonded to one side of the electrolyte layer 20 in the thickness direction (upper side in Figure 1). The anode electrode layer 22 is bonded to the other side of the electrolyte layer 20 in the thickness direction (lower side in Figure 1). The side of the cathode electrode layer 21 opposite to the electrolyte layer 20 is covered by the gas diffusion layer 23. The side of the anode electrode layer 22 opposite to the electrolyte layer 20 is covered by a gas diffusion layer 23 different from the gas diffusion layer 23 mentioned above.

[0023] The separator 14 is positioned on both the cathode side and the anode side of the membrane electrode gas diffusion layer assembly 13. Multiple ribs 19 on the separator 14 are formed by bending the body 15 of the separator 14 so that they protrude in the thickness direction of the separator 14. The separator 14 located on the cathode side of the membrane electrode gas diffusion layer assembly 13 and the separator 14 located on the anode side of the membrane electrode gas diffusion layer assembly 13 have the same shape. However, the cathode-side separator 14 has its front and back sides (thickness direction) reversed compared to the anode-side separator 14.

[0024] Multiple ribs 19 on the cathode-side separator 14 protrude toward the cathode-side gas diffusion layer 23. These ribs 19 are in contact with the cathode-side gas diffusion layer 23. A flow path 18 for oxidizing gas is formed between the multiple ribs 19 on the separator 14 and between the body 15 of the separator 14 and the gas diffusion layer 23. Multiple ribs 19 on the anode-side separator 14 protrude toward the anode-side gas diffusion layer 23. These ribs 19 are in contact with the anode-side gas diffusion layer 23. A flow path 18 for fuel gas is formed between the multiple ribs 19 on the separator 14 and between the body 15 of the separator 14 and the gas diffusion layer 23.

[0025] The space between adjacent separators 14 serves as a flow path 25 for refrigerant. More specifically, adjacent separators 14 are in contact with each other at locations corresponding to the bottom 24 of the flow path 18 in the main body 15. The flow path 25 is formed between the main body 15 of the adjacent separators 14 at locations other than those in contact with each other.

[0026] <Details of rib 19 and channel 18> Figure 3 shows the separator 14 in contact with the anode side of the membrane electrode gas diffusion layer assembly 13, viewed from the front side. Figure 4 shows the separator 14 in contact with the cathode side of the membrane electrode gas diffusion layer assembly 13, viewed from the back side.

[0027] As can be seen from Figures 3 and 4, the main body 15 is divided into central regions AC1, AC2, and AC3, and turn regions AT1 and AT2. The central regions AC1, AC2, and AC3 extend along the long side of the main body 15 and are aligned in the direction of the short side that intersects with the aforementioned long side of the main body 15. The turn regions AT1 and AT2 extend along the short side of the main body 15 and are located corresponding to the longitudinal ends of adjacent central regions AC1, AC2, and AC3.

[0028] Multiple ribs 19 for forming the flow path 18 are formed on the main body 15 so as to extend in a wave-like manner. Therefore, the flow path 18 formed between the multiple ribs 19 also extends in a wave-like manner corresponding to the ribs 19. The flow path 18 is formed by a central flow path section 18a and a turn flow path section 18b. The central flow path section 18a passes through multiple central regions AC1, AC2, and AC3 in the longitudinal direction. Multiple central flow path sections 18a are formed in one central region AC1, AC2, or AC3. The turn flow path section 18b passes through turn regions AT1 and AT2 in the longitudinal direction and connects the central flow path sections 18a of adjacent central regions AC1, AC2, and AC3.

[0029] The multiple ribs 19 in the main body 15 are formed as follows: Multiple central flow channels 18a are formed within the central regions AC1, AC2, AC2, and the multiple ribs 19 are formed so that the turn flow channels 18b in the turn regions AT1, AT2 are connected to the multiple central flow channels 18a in the central regions AC1, AC2, AC3. Furthermore, the multiple ribs 19 in the main body 15 are formed so that there are multiple turn flow channels 18b in the turn regions AT1, AT2. In addition, the multiple ribs 19 are formed so that the flow channel width of the central flow channel 18a and the flow channel width of the turn flow channel 18b in the flow channel 18 are constant.

[0030] <Details of the central channel section 18a and the turn channel section 18b> The central regions AC1, AC2, and AC3 consist of three regions: the first central region AC1, the second central region AC2, and the third central region AC3. The turn regions AT1 and AT2 consist of two regions: the first turn region AT1 and the second turn region AT2.

[0031] The turn channel section 18b within the first turn region AT1 connects the central channel sections 18a of the adjacent first central region AC1 and second central region AC2 at one end in their longitudinal direction. The turn channel section 18b within the second turn region AT2 connects the central channel sections 18a of the adjacent second central region AC2 and third central region AC3 at the other end in their longitudinal direction.

[0032] The number of central flow channels 18a in the first central region AC1, the number of central flow channels 18a in the second central region AC2, and the number of central flow channels 18a in the third central region AC3 are the same. Also, the number of turn flow channels 18b in the first turn region AT1 and the number of turn flow channels 18b in the second turn region AT2 are the same. In other words, multiple ribs 19 are formed on the main body 15 to achieve this.

[0033] <Regarding the bottom 24 of the channel 18 in the channel 25 and the main body 15> Figure 5 shows the difference in the direction of the flow path 18 when the anode-side separator 14 and the cathode-side separator 14 in the fuel cell cell 11 are superimposed. As can be seen from Figure 5, the anode-side separator 14 and the cathode-side separator 14 are in a state where their front and back surfaces in the thickness direction are reversed. In adjacent fuel cell cells 11 in the fuel cell stack, the portions of the anode-side separator 14 and the cathode-side separator 14 corresponding to the bottom 24 of the flow path 18 in the main body 15 are in contact with each other.

[0034] The portion of the main body 15 corresponding to the bottom 24 of the flow path 18 extends in a wavy pattern along the ribs 19, as the ribs 19 of the main body 15 are formed to extend in a wavy pattern. However, as described above, the front and back sides of the anode-side separator 14 and the cathode-side separator 14 are reversed. Therefore, the portion of the anode-side separator 14 corresponding to the bottom 24 of the flow path 18 and the portion of the cathode-side separator 14 corresponding to the bottom 24 of the flow path 18 extend in different directions.

[0035] As a result, the portion of the anode-side separator 14 corresponding to the bottom 24 of the flow path 18 and the portion of the cathode-side separator 14 corresponding to the bottom 24 of the flow path 18 come into contact with each other at an intersecting position. In addition, a flow path 25 for refrigerant is formed between the anode-side separator 14 and the cathode-side separator 14 at a position other than the aforementioned contact point. This refrigerant passes through the flow path 25 from one of the two holes 16 located in the center of the short side of the body 15 of the separator 14 to the other hole 16, as indicated by the arrow.

[0036] According to the embodiment described in detail above, the following effects and advantages can be obtained. (1) In the flow channels 18 formed in the body 15 of the separator 14 in the fuel cell cell 11, the turn flow channel sections 18b in the turn regions AT1 and AT2 are connected to multiple central flow channel sections 18a in the central regions AC1, AC2, and AC3. Therefore, the number of turn flow channel sections 18b in one of the regions AT1 and AT2 can be made less than the number of central flow channel sections 18a in one of the central regions AC1, AC2, and AC3. This makes it possible to shorten the overall width of the turn flow channel sections 18b in the direction in which the central regions AC1, AC2, and AC3 extend, in other words, the width of the turn regions AT1 and AT2. As a result of shortening the width of the turn regions AT1 and AT2, the central regions AC1, AC2, AC3 and the central flow channel sections 18a can be made longer.

[0037] By sandwiching the membrane electrode gas diffusion layer assembly 13 from the anode side and the cathode side with a separator 14 that has been reversed, the gas flow in the channel 18 on the anode side and the gas flow in the channel 18 on the cathode side become as follows: That is, the direction of gas flow in the central channel section 18a of the channel 18 on the anode side and the direction of gas flow in the central channel section 18a of the channel 18 on the cathode side are opposite. By making the gas flow in opposite directions in the central channel section 18a on the anode side and the central channel section 18a on the cathode side in this way, the power generation efficiency of the membrane electrode gas diffusion layer assembly 13 is improved. Furthermore, as described above, the length of the central channel section 18a can be increased, so the power generation efficiency can be effectively improved.

[0038] (2) In the turn regions AT1 and AT2 of the main body 15, multiple ribs 19 for forming multiple turn channel sections 18b are in contact with the membrane electrode gas diffusion layer assembly 13. Therefore, the multiple ribs 19 prevent the membrane electrode gas diffusion layer assembly 13 from expanding into and returning to its original state within the turn channel section 18b as shown by the arrows in Figure 6, in response to pressure fluctuations in the channel 18. As a result, the deterioration of the membrane electrode gas diffusion layer assembly 13 due to the above fluctuations of the membrane electrode gas diffusion layer assembly 13 can be suppressed.

[0039] (3) Since the flow width of the central flow section 18a and the flow width of the turn flow section 18b in the flow path 18 are constant, the area of ​​the membrane electrode gas diffusion layer assembly 13 exposed to the turn flow section 18b does not increase. Therefore, the membrane electrode gas diffusion layer assembly 13 is less likely to expand into the turn flow section 18b and return to its original position in response to pressure fluctuations in the flow path 18, as shown by the arrows in Figure 6. As a result, deterioration of the membrane electrode gas diffusion layer assembly 13 in response to the above fluctuations can be suppressed.

[0040] (4) In the central regions AC1, AC2, and AC3, the number of central flow channels 18a in the first central region AC1, the number of central flow channels 18a in the second central region AC2, and the number of central flow channels 18a in the third central region AC3 are the same. Also, in the turn regions AT1 and AT2, the number of turn flow channels 18b in the first turn region AT1 and the number of turn flow channels 18b in the second turn region AT2 are the same. Therefore, it is possible to suppress the bias in the distribution of the gas flowing through the flow channels 18 to the membrane electrode gas diffusion layer assembly 13. Consequently, it is possible to suppress the shortening of the product life of the membrane electrode gas diffusion layer assembly 13 that occurs due to bias in the distribution of the gas flowing through the flow channels 18 to the membrane electrode gas diffusion layer assembly 13.

[0041] (5) The fuel cell cell 11 is formed by sandwiching the membrane electrode gas diffusion layer assembly 13 from the anode side and the cathode side with a separator 14 that has been inverted. Furthermore, a cell stack is formed by the fuel cell cells 11 as follows. That is, a cell stack is formed by stacking the fuel cell cells 11 in the thickness direction. In adjacent fuel cell cells 11 in such a cell stack, the separators 14 are adjacent to each other and the portions corresponding to the bottom 24 of the flow path 18 between the ribs 19 are in contact. In this configuration, since the ribs 19 in the body 15 of the separator 14 extend in a wavy shape, the portions corresponding to the bottom 24 of the flow path 18 between the ribs 19 also extend in a wavy shape. When these portions come into contact with each other, they extend in different directions. As a result, the portions do not interlock in an alternating manner. Therefore, as the above-mentioned parts interlock in an alternating manner, when the cell stack is pressed in the stacking direction of the fuel cell cells 11, the surface pressure acting from the main body 15 of the separator 14 to the membrane electrode gas diffusion layer assembly 13 decreases, which can suppress deterioration of power generation efficiency.

[0042] (6) As shown in Figure 7, even when the turn channel section 18b is in a straight line inclined with respect to the short side of the body 15 of the separator 14, when the portions corresponding to the bottom 24 of the channel 18 between the ribs 19 in the body 15 come into contact with each other, these portions extend in different directions. As a result, when the cell stack is pressed in the stacking direction of the fuel cell cells 11, the surface pressure acting from the body 15 to the membrane electrode gas diffusion layer assembly 13 decreases, which suppresses deterioration of power generation efficiency. However, if the turn channel section 18b is in a straight line inclined with respect to the short side of the body 15 of the separator 14, the area where the turn channel section 18b does not exist becomes larger, as shown by the dashed line in Figure 7, and power generation efficiency decreases.

[0043] However, as shown in Figures 3 and 4, the turn channel section 18b is formed to extend in a wavy shape, so the area where the turn channel section 18b does not exist in the channel 18 does not become large, as shown by the dashed line in Figure 7. Therefore, the decrease in power generation efficiency that would occur as such areas become larger is suppressed.

[0044] The above embodiment can also be modified as follows, for example. The above embodiment and the following modifications can be combined and implemented to the extent that they do not contradict each other technically. At least one of the central flow channel portion 18a and the turn flow channel portion 18b in the flow channel 18 may be formed to extend in a straight line.

[0045] The number of turn flow channels 18b in the first turn region AT1 may be different from the number of turn flow channels 18b in the second turn region AT2. In this case, the number of turn flow channels 18b in one of the two turn regions, AT1 or AT2, may be the same as the number of central flow channels 18a in the central regions AC1, AC2, and AC3.

[0046] The number of central flow channels 18a in the first central region AC1, the number of central flow channels 18a in the second central region AC2, and the number of central flow channels 18a in the third central region AC3 do not necessarily have to be the same.

[0047] The flow width of the central flow section 18a and the flow width of the turn flow section 18b in the flow path 18 do not necessarily have to be constant. The number of turn channel sections 18b in the first turn region AT1 may be limited to one, or the number of turn channel sections 18b in the second turn region AT2 may be limited to one.

[0048] Next, we will describe the technical concept that can be understood from the above embodiment. (A) It comprises a rectangular plate-shaped body that can be positioned on both sides in the thickness direction of the membrane electrode gas diffusion layer assembly, The main body forms a channel for flowing gas between itself and the membrane electrode gas diffusion layer assembly, The main body is divided into a central region and a turning region. The central region extends along one side of the main body and is aligned in the direction of another side of the main body that intersects with that side. The turn region extends along the other side and is located corresponding to the longitudinal ends of adjacent central regions. In a fuel cell separator, the flow path is formed by a central flow path section passing through a plurality of central regions in the longitudinal direction, and a turn flow path section passing through the turn region and connecting the central flow path sections of adjacent central regions, The main body has a plurality of ribs that protrude toward the membrane electrode gas diffusion layer assembly and come into contact with the membrane electrode gas diffusion layer assembly. The flow path is formed between a plurality of ribs, A fuel cell separator in which a plurality of central flow channels are formed within the central region, and a plurality of ribs are formed such that the turn flow channels within the turn region are connected to the plurality of central flow channels within the central region.

[0049] (B) A separator for a fuel cell according to (A), wherein the plurality of ribs in the main body are formed such that there are a plurality of turn flow channels in the turn region.

[0050] (C) A separator for a fuel cell according to (A) or (B), wherein the plurality of ribs are formed such that the flow width of the central flow channel and the flow width of the turn flow channel in the flow channel are constant.

[0051] (D) The multiple central regions are the first central region, the second central region, and the third central region. The aforementioned turn regions are the first turn region and the second turn region, The turn channel portion within the first turn region connects the central channel portions of the adjacent first central region and second central region at one end of their respective longitudinal directions. The turn channel portion within the second turn region connects the central channel portions of the adjacent second central region and the third central region at their other ends in the longitudinal direction. A fuel cell separator according to any one of (A) to (C), wherein the number of central flow channels in the first central region, the number of central flow channels in the second central region, and the number of central flow channels in the third central region are the same, and a plurality of ribs are formed such that the number of turn flow channels in the first turn region and the number of turn flow channels in the second turn region are the same.

[0052] (E) A fuel cell separator according to any one of (A) to (D), wherein the plurality of ribs are formed on the main body to extend in a wave-like manner. [Explanation of symbols]

[0053] 11… Fuel cell 12… Resin plate 13…Membrane electrode gas diffusion layer assembly 14... Separator 15…Main unit 16...hole 17...Sealing material 18…flow channel 18a...Central channel section 18b... Turn channel section 19… Rib 20...Electrolyte layer 21... Cathode electrode layer 22... Anode electrode layer 23…Gas diffusion layer 24…bottom 25…flow channel

Claims

1. It comprises a rectangular plate-shaped body that can be positioned on both sides in the thickness direction of the membrane electrode gas diffusion layer assembly, The main body forms a channel for flowing gas between itself and the membrane electrode gas diffusion layer assembly, The main body is divided into a central region and a turning region. The central region extends along one side of the main body and is aligned in the direction of another side of the main body that intersects with that side. The turn region extends along the other side and is located corresponding to the longitudinal ends of adjacent central regions. In a fuel cell separator, the flow path is formed by a central flow path section passing through a plurality of central regions in the longitudinal direction, and a turn flow path section passing through the turn region and connecting the central flow path sections of adjacent central regions, The main body has a plurality of ribs that protrude toward the membrane electrode gas diffusion layer assembly and come into contact with the membrane electrode gas diffusion layer assembly. The flow path is formed between a plurality of ribs, A fuel cell separator in which a plurality of central flow channels are formed within the central region, and a plurality of ribs are formed such that the turn flow channels within the turn region are connected to the plurality of central flow channels within the central region.

2. The fuel cell separator according to claim 1, wherein the plurality of ribs in the main body are formed such that there are a plurality of turn flow channels in the turn region.

3. A fuel cell separator according to claim 1 or 2, wherein the plurality of ribs are formed such that the flow width of the central flow channel and the flow width of the turn flow channel in the flow channel are constant.

4. The multiple central regions are the first central region, the second central region, and the third central region. The aforementioned turn regions are the first turn region and the second turn region, The turn channel portion within the first turn region connects the central channel portions of the adjacent first central region and second central region at one end of their respective longitudinal directions. The turn channel portion within the second turn region connects the central channel portions of the adjacent second central region and the third central region at their other ends in the longitudinal direction. A fuel cell separator according to claim 1, wherein a plurality of ribs are formed such that the number of central flow channels in the first central region, the number of central flow channels in the second central region, and the number of central flow channels in the third central region are the same, and the number of turn flow channels in the first turn region and the number of turn flow channels in the second turn region are the same.

5. The fuel cell separator according to claim 1, wherein the plurality of ribs are formed on the main body to extend in a wave-like manner.

6. The membrane electrode gas diffusion layer assembly is sandwiched from both sides in the thickness direction by two rectangular plate-shaped separators with their front and back sides reversed. A flow channel for gas is formed between the separator and the membrane electrode gas diffusion layer assembly. The separator is divided into a central region and a turn region. The central region extends along one side of the separator and is aligned in the direction of the other side of the separator that intersects with the aforementioned side. The turn region extends along the other side and is located corresponding to the longitudinal ends of adjacent central regions. In a fuel cell, the flow path is formed by a central flow path section passing through a plurality of central regions in the longitudinal direction, and a turn flow path section passing through the turn region and connecting the central flow path sections of adjacent central regions. The separator has a plurality of ribs that protrude toward the membrane electrode gas diffusion layer assembly and come into contact with the membrane electrode gas diffusion layer assembly. The flow path is formed between a plurality of ribs, A fuel cell in which a plurality of central flow channels are formed within the central region, and a plurality of ribs are formed such that the turn flow channels within the turn region are connected to the plurality of central flow channels within the central region.

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