Separator for a fuel cell and single cell for a fuel cell

Abstract

A separator for a fuel cell has a rectangular, plate-shaped body. The body forms passages through which gas flows. The body has central regions and a reversal region. The central regions extend along one side of the body and are oriented in the same direction as another side of the body, intersecting that side. The passages have several central passage sections extending longitudinally through each central region and a reversal passage section extending through the reversal region, connecting the central passage sections of adjacent central regions. The ribs are designed such that two or more central passage sections are formed in each of the central regions, and the reversal passage section in the reversal region connects to two or more central passage sections in the corresponding central region.

Description

1. Area

[0001] The present disclosure relates to a separator for a fuel cell and a single cell for a fuel cell. 2. Description of the state of the art

[0002] As disclosed in JP2005-190795A, a fuel cell stack is formed by stacking individual fuel cell units in the thickness direction. An individual unit is formed by sandwiching a membrane electrode gas diffusion layer assembly with rectangular, plate-shaped separators from opposite sides in the thickness direction. The fuel cell separator has a body with parallel ribs. The ribs project from the body to contact the membrane electrode gas diffusion layer assembly. Passages for gas flow are formed between the body and the membrane electrode gas diffusion layer assembly, and between the ribs.

[0003] One of the opposite sides of the membrane electrode diffusion layer assembly (MED) in the thickness direction is the anode side, and the other side is the cathode side. Fuel gas (e.g., hydrogen) flows through the passage between the anode side of the MED and the separator located on the anode side. Oxide gas (e.g., air) flows through the passage between the cathode side of the MED and the separator located on the cathode side. In each individual cell, power is generated based on the reaction between the fuel gas and the oxidation gas at the MED.

[0004] The body of each separator has central regions and reversal regions. The central regions extend along one side of the body and are arranged parallel to the side that intersects them. The reversal regions extend along the other side of the body and are positioned to correspond to the ends of longitudinally adjacent central regions. The passages are formed by several central passage sections extending longitudinally through the central regions, as well as by reversal passage sections extending through the reversal regions and connecting the central passage sections of adjacent central regions. The passages formed by the central passage sections and the reversal passage sections are parallel. In other words, the ribs on the body are designed to define the multiple passages.

[0005] In each individual cell, the separator on the anode side and the separator on the cathode side are identical components, reversed relative to each other from front to back. In the membrane electrode gas diffusion layer assembly of the configuration described above, the direction of the fuel gas in the central passages on the anode side is opposite to the direction of the oxidation gas in the central passages on the cathode side.

[0006] In the membrane electrode gas diffusion layer assembly of a single cell, the power generation efficiency is maximized when the flow direction of the fuel gas flowing through the channels on the anode side is opposite to the flow direction of the oxidation gas flowing through the channels on the cathode side. Accordingly, it is advantageous to make the central channel sections as long as possible to increase the power generation efficiency of the individual cell.

[0007] The separator body in the preceding publication has several reverse passage sections connected to multiple central passage sections of the passages. Accordingly, one approach to lengthening the central passage sections of the passages is to decrease the overall width of the reverse passage sections in the direction in which the central passage sections extend.

[0008] However, since the number of reverse passage sections corresponds to the number of central passage sections in each central area, there is a limit to how much the total width of the reverse passage sections can be reduced in the direction of expansion of the central passage sections. Because the length of the central passage sections cannot be easily increased, it was correspondingly difficult to significantly improve the power generation efficiency of the individual cell. Summary

[0009] This summary is provided to introduce a selection of concepts in a simplified form, which are further explained in the detailed description below. This summary is not intended to identify essential features or characteristics of the claimed subject matter, nor is it intended to assist in determining the scope of the claimed subject matter.

[0010] In general terms, a fuel cell separator has a rectangular, plate-shaped body that can be arranged on each side in one thickness direction of a membrane electrode gas diffusion layer assembly. The body forms gas flow passages through which gas flows between the body and the membrane electrode gas diffusion layer assembly. The body has central regions and a reversal region.

[0011] The central regions extend along one side of the body and are oriented in the same direction as another side of the body, intersecting one side. The reversal region extends along the other side of the body and is positioned longitudinally at the ends of adjacent central regions. The passages have multiple central passage sections extending longitudinally through each central region and a reversal passage section extending through the reversal region, connecting the central passage sections of adjacent central regions. The body has several ribs projecting toward the membrane electrode gas diffusion layer assembly to make contact with it. The passages are formed between the ribs.The ribs are designed such that two or more of the central passage sections are formed in each of the central areas, and the reversal passage section in the reversal area is connected to two or more of the central passage sections in the corresponding central area.

[0012] In a more general sense, a single fuel cell has a membrane electrode gas diffusion layer assembly and two separators that sandwich the assembly in the thickness direction from opposite sides. The separators are arranged in a front-to-back orientation relative to each other. Gas flow passages are formed between the separator and the membrane electrode gas diffusion layer assembly, through which gas flows. The separator has central regions and a reversal region. The central regions extend along one side of the separator and are oriented in the same direction as another side of the separator, intersecting one side. The reversal region extends along the other side of the separator and is positioned longitudinally at the ends of adjacent central regions.The passages have multiple central passage sections extending longitudinally through each central region, and a reversal passage section extending through the reversal region and connecting the central passage sections of adjacent central regions. The separator has multiple ribs projecting toward the membrane electrode gas diffusion layer assembly to make contact with it. The passages are formed between the ribs. The ribs are configured such that two or more central passage sections are present in each of the central regions, and the reversal passage section in the reversal region connects to two or more central passage sections in the corresponding central region.

[0013] Further features and aspects will become apparent from the following detailed description, the drawings and the claims. BRIEF DESCRIPTION OF THE DRAWINGS Fig. Figure 1 is a perspective view showing a single cell of a fuel cell. Fig. 2 is a cross-sectional view of a cell stack, in which individual cells are filled with the data from Fig. They are stacked in a visible structure. Fig. 3 is a top view showing a front view of the body of one of the Fig. 1 visible separators. Fig. 4 is a top view showing the back of the body of one of the Fig. 1 visible separators. Fig. Figure 5 is a top view showing a state in which the separator is on the anode side and the separator is on the cathode side in the Fig. are stacked in one visible single cell. Fig. 6 is a schematic cross-sectional view of a reversing passage section in an area where the Fig. 3 and Fig. 4 Separator shown and its surroundings. Fig. Figure 7 is a top view showing a comparative example of a separator.

[0014] In the drawings and the detailed description, the same reference symbols refer to the same elements. The drawings may not be to scale, and the relative size, proportions, and representation of elements in the drawings may be exaggerated for clarity, illustration, and simplification. DETAILED DESCRIPTION

[0015] This description provides a comprehensive understanding of the described methods, devices, and / or systems. Variations and equivalents of the described methods, devices, and / or systems are obvious to a person skilled in the art. The sequence of operations is exemplary and, with the exception of operations that necessarily follow a specific order, may be modified by a person skilled in the art. Descriptions of functions and designs known to a person skilled in the art may be omitted.

[0016] Exemplary embodiments can take various forms and are not limited to the examples described. However, the examples described are thorough and complete, conveying the entire scope of the disclosure to a person skilled in the art.

[0017] In this description, “at least one of A and B” is to be understood as meaning “only A, only B or both A and B”.

[0018] A separator 14 for a fuel cell and a single cell 11 for a fuel cell according to an embodiment are now described with reference to the Fig. 1 to 7 described.

[0019] Fig. Figure 1 shows a single cell 11 used to form a fuel cell stack. The single cell 11 has a plastic plate 12, a membrane electrode gas diffusion layer assembly 13, and separators 14. The plastic plate 12 is shaped as a rectangular frame. The outer edge of the membrane electrode gas diffusion layer assembly 13 is joined to the plastic plate 12. The plastic plate 12 and the membrane electrode gas diffusion layer assembly 13 are sandwiched together by the separators 14, which are arranged on opposite sides in the thickness direction. Each separator 14 is in the form of a rectangular plate that corresponds to the outer shape of the plastic plate 12.

[0020] The fuel cell stack is formed by stacking several individual cells 11 in the thickness direction. The plastic plates 12 and the separators 14 of the cells 11 each have holes 16. Three of the holes 16 are located longitudinally at one end of the individual cell 11, and the other three are located longitudinally at the other end of the individual cell 11. One of the holes 16 at one end in the longitudinal direction of the individual cell 11 is paired with one of the holes 16 at the other end. Each pair of holes 16 serves to allow a fluid (e.g., fuel gas such as hydrogen, oxidizing gas such as air, or coolant) to flow through it.

[0021] The separators 14 each have a body 15 made of metal (e.g., stainless steel, titanium, or aluminum) and shaped like a rectangular plate. The body 15 has several ribs 19 running parallel to each other. A sealing element 17 is arranged between the body 15 of each separator 14 and the plastic plate 12. The sealing element 17 can be provided on either the front or back side of the plastic plate 12 in the thickness direction.

[0022] The sealing element 17, located on the front surface of the plastic plate 12, surrounds a pair of holes 16, the pair being positioned on one of the two diagonal lines of the plastic plate 12 and the corresponding separator 14. The sealing element 17 also surrounds the anode side of the membrane electrode gas diffusion layer assembly 13. The sealing element 17 also surrounds the ribs 19 in the separator 14 on the anode side. Furthermore, a passage 18 is defined between adjacent ribs 19 in the separator 14, through which fuel gas flows. Fuel gas can be supplied to the passages 18 through the pair of holes 16.

[0023] Furthermore, the sealing element 17, located on the rear side of the plastic plate 12, surrounds a pair of holes 16 positioned on the other of the two diagonal lines of the plastic plate 12 and the corresponding separator 14. The sealing element 17 also surrounds the cathode side of the membrane electrode gas diffusion layer assembly 13. The sealing element 17 also surrounds the ribs 19 in the separator 14 on the cathode side. Additionally, a passage 18 is defined between adjacent ribs 19 in the separator 14, through which oxidation gas flows. Oxide gas can be supplied to the passages 18 through the pair of holes 16.

[0024] In the cell stack of individual cells 11, the separator 14 on the anode side of one of the individual cells 11 and the separator 14 on the cathode side of another individual cell 11 are located next to each other. The adjacent separators 14 are welded together around two pairs of holes 16 arranged on the diagonals of the separators 14, but not around the holes 16 located at the center of each short side of the separators 14. Furthermore, the outer edges of the adjacent separators 14 are welded together. This allows coolant to flow through the space between the adjacent separators 14 via the holes 16 located at the center of the separators 14 in the direction of the short sides.

[0025] In the fuel cell stack of individual cells 11, the fuel gas flows along the anode side of the membrane electrode gas diffusion layer assembly 13, and the oxidation gas flows along the cathode side of the membrane electrode gas diffusion layer assembly 13. As the fuel gas and the oxidation gas flow along the anode and cathode sides of the membrane electrode gas diffusion layer assembly 13, respectively, power is generated due to the reaction between the fuel gas and the oxidation gas within the membrane electrode gas diffusion layer assembly 13. To limit a temperature increase of the cell stack due to this power generation, the coolant flows, as described above, through the space between the separators 14 of adjacent individual cells 11. The coolant cools the cell stack.

[0026] As from Fig. As can be seen in Figure 2, the membrane-electrode-gas diffusion layer assembly 13 of each individual cell 11 has 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, by a solid polymer membrane. The cathode electrode layer 21 is oriented with one side of the electrolyte layer 20 in the thickness direction (the top side in Fig. 1) joined together. The anode electrode layer 22 is joined to the other side in the thickness direction of the electrolyte layer 20 (the underside in Fig. 1) joined together. The surface of the cathode electrode layer 21 opposite the electrolyte layer 20 is covered with the gas diffusion layer 23. The surface of the anode electrode layer 22 opposite the electrolyte layer 20 is covered with a further gas diffusion layer 23, which differs from the previously mentioned gas diffusion layer 23.

[0027] Two separators 14 are located on the cathode side and the anode side of the membrane electrode gas diffusion layer assembly 13. The ribs 19 in each separator 14 are formed by bending the body 15 of the separator 14 so that they project in the direction of the separator's thickness. The separator 14 on the cathode side of the membrane electrode gas diffusion layer assembly 13 and the separator 14 on the anode side of the membrane electrode gas diffusion layer assembly 13 have the same shape. However, the separator 14 on the cathode side is oriented in the opposite direction to the separator 14 on the anode side, from front to back.

[0028] The multiple ribs 19 of the cathode-side separator 14 project towards the gas diffusion layer 23 on the cathode side. These ribs 19 are in contact with the gas diffusion layer 23 on the cathode side. The spaces between the ribs 19 of the separator 14 and between the body 15 of the separator 14 and the gas diffusion layer 23 form passages 18 through which oxidation gas flows. The multiple ribs 19 of the anode-side separator 14 project towards the gas diffusion layer 23 on the anode side. These ribs 19 are in contact with the gas diffusion layer 23 on the anode side. The spaces between the ribs 19 of the separator 14 and between the body 15 of the separator 14 and the gas diffusion layer 23 form passages 18 through which fuel gas flows.

[0029] A gap between the adjacent separating elements 14 serves as a passage 25 through which the coolant flows. Specifically, the adjacent separating elements 14 are in contact with each other at sections corresponding to the bottoms 24 of the passages 18 in the bodies 15. The passage 25 is formed between the bodies 15 of the adjacent separating elements 14 at positions other than the sections that are in contact with each other. Details of ribs 19 and passages 18

[0030] Fig. Figure 3 shows the front side of the separator 14, which is in contact with the anode side of the membrane electrode gas diffusion layer assembly 13. Fig. Figure 4 shows the back side of the separator 14, which is in contact with the cathode side of the membrane electrode gas diffusion layer assembly 13.

[0031] As from the Fig. 3 and Fig. As can be seen in Figure 4, each body has 15 central regions AC1, AC2, AC3 and reversal regions AT1, AT2. The central regions AC1, AC2, AC3 extend along a longitudinal side, which is one side of the body 15, and are arranged along a transverse side, which is another side intersecting the longitudinal side. The reversal regions AT1, AT2 extend along the short side of the body 15 and are each located at a position corresponding to the longitudinal ends of adjacent central regions AC1, AC2, AC3.

[0032] The ribs 19, which form the passages 18, are shaped on the body 15 in such a way that they extend in a wave-like pattern. The passages 18 formed between the ribs 19 also extend in a wave-like pattern corresponding to the ribs 19. The passages 18 have central passage sections 18a and reversal passage sections 18b. The central passage sections 18a extend longitudinally through each of the central regions AC1, AC2, AC3. Each of the central regions AC1, AC2, AC3 has several central passage sections 18a. The reversal passage sections 18b extend longitudinally through the reversal regions AT1, AT2 and connect the central passage sections 18a of adjacent central regions AC1, AC2, AC3.

[0033] The ribs 19 in the body 15 are configured as follows. The ribs 19 are configured such that several central passage sections 18a are formed in each of the central regions AC1, AC2, AC3, and the reversal passage sections 18b in each of the reversal regions AT1, AT2 are connected to the central passage sections 18a in the corresponding central regions AC1, AC2, AC3. The ribs 19 are configured such that the reversal regions AT1, AT2 each have several reversal passage sections 18b. Furthermore, the ribs 19 are configured such that the width of each central passage section 18a and the width of each reversal passage section 18b are constant in the passages 18. Details on the central passage sections 18a and the reverse passage sections 18b

[0034] The central areas AC1, AC2, and AC3 each have three sub-areas: a first central area AC1, a second central area AC2, and a third central area AC3. Furthermore, the reversal areas AT1 and AT2 each have two sub-areas: a first reversal area AT1 and a second reversal area AT2.

[0035] The first central area AC1 and the second central area AC2 are adjacent, and the reversal passage sections 18b in the first reversal area AT1 connect the central passage sections 18a of the first central area AC1 and the central passage sections 18a of the second central area AC2 longitudinally at one end. The second central area AC2 and the third central area AC3 are adjacent, and the reversal passage sections 18b in the second reversal area AT2 connect the central passage sections 18a of the second central area AC2 and the central passage sections 18a of the third central area AC3 longitudinally at the other end.

[0036] The number of central passage sections 18a in the first central region AC1, the number of central passage sections 18a in the second central region AC2, and the number of central passage sections 18a in the third central region AC3 are equal. The number of reversal passage sections 18b in the first reversal region AT1 and the number of reversal passage sections 18b in the second reversal region AT2 are equal. In other words, the ribs 19 are formed in the body 15 such that this configuration is achieved. Passage 25 and floors 24 of passages 18 in body 15

[0037] Fig. Figure 5 shows a difference in the direction in which the passages 18 extend when the anode-side separator 14 and the cathode-side separator 14 are stacked in each individual cell 11. As can be seen from Fig. As can be seen in Figure 5, the anode-side separator 14 and the cathode-side separator 14 are reversed relative to each other in the thickness direction, from front to back. In the individual cells 11, which are located next to each other in the cell stack of the fuel cell, the anode-side separator 14 and the cathode-side separator 14 are in contact at sections that correspond to the bottoms 24 of the passages 18 in the bodies 15.

[0038] Since the ribs 19 of the bodies 15 are designed to extend in a wave-like manner, the sections of the bodies 15 corresponding to the bottoms 24 of the passages 18 extend in a wave-like manner along the ribs 19. However, as described above, the anode-side separator 14 and the cathode-side separator 14 are reversed relative to each other from front to back. Accordingly, the direction in which the sections corresponding to the bottoms 24 of the passages 18 extend in the anode-side separator 14 differs from the direction in which the sections corresponding to the bottoms 24 of the passages 18 extend in the cathode-side separator 14.

[0039] Consequently, the sections in the anode-side separator 14 corresponding to the bottoms 24 of the passages 18 and the sections in the cathode-side separator 14 corresponding to the bottoms 24 of the passages 18 are in contact at their intersection points. Furthermore, the passage 25, through which coolant flows, is formed between the anode-side separator 14 and the cathode-side separator 14 at positions other than those described above where the separators 14 are in contact. The coolant flows through the passage 25 from one of the two holes 16 located in the center in the short side direction of the bodies 15 of the separators 14 to the other hole 16, as indicated by the arrows.

[0040] The present embodiment, as described above, has the following operational advantages.

[0041] In the passages 18 formed in the bodies 15 of the separators 14 in each individual cell 11 of the fuel cell, each of the reverse passage sections 18b in the reverse regions AT1, AT2 is connected to two or more of the central passage sections 18a in the corresponding central regions AC1, AC2, AC3. Accordingly, the number of reverse passage sections 18b in each of the regions AT1, AT2 can be made smaller than the number of central passage sections 18a in each of the central regions AC1, AC2, AC3. This reduces the overall width of the reverse passage sections 18b in the direction in which the central regions AC1, AC2, AC3 extend. In other words, the width of each of the reverse regions AT1, AT2 is reduced. Since the width of each of the reverse regions AT1, AT2 is thus reduced, the central regions AC1, AC2, AC3 and the central passage sections 18a can be lengthened.

[0042] Since the membrane electrode gas diffusion layer assembly 13 is sandwiched between the anode and cathode sides by the two separators 14, which are reversed relative to each other, the gas flow in the gas flow passages 18 on the anode side and the gas flow in the gas flow passages 18 on the cathode side is as follows. The direction of the gas flowing through the central passage sections 18a of the passages 18 on the anode side is opposite to the direction of the gas flowing through the central passage sections 18a of the passages 18 on the cathode side. Because the gas flows in opposite directions between the central passage sections 18a on the anode side and the central passage sections 18a on the cathode side, the power generation efficiency of the membrane electrode gas diffusion layer assembly 13 is improved.Since the central passage sections 18a are lengthened as described above, the power generation efficiency is effectively improved.

[0043] In the reversal regions AT1, AT2 of the body 15, the ribs 19 are in contact with the membrane-electrode gas diffusion layer assembly 13 to form the reversal passage sections 18b. Accordingly, the ribs 19 suppress pressure fluctuations within the passages 18, which would otherwise cause the membrane-electrode gas diffusion layer assembly 13 to bulge into and out of the reversal passage sections 18b, as indicated by the arrows in Fig. 6 is displayed. This suppresses deterioration of the membrane electrode gas diffusion layer assembly 13 due to such fluctuations of the membrane electrode gas diffusion layer assembly 13.

[0044] (3) Since the widths of the central passage sections 18a and the reverse passage sections 18b are constant in the passages 18, the area of ​​the membrane electrode gas diffusion layer assembly 13 exposed to the reverse passage sections 18b is not excessively large. Consequently, it is unlikely that the membrane electrode gas diffusion layer assembly 13 will bulge inward and outward from the reverse passage sections 18b in response to pressure fluctuations within the passages 18, as indicated by the arrows in Fig. 6 is displayed. This suppresses deterioration of the membrane electrode gas diffusion layer assembly 13 due to such fluctuations of the membrane electrode gas diffusion layer assembly 13.

[0045] (4) The number of central passage sections 18a in the first central area AC1, the number of central passage sections 18a in the second central area AC2, and the number of central passage sections 18a in the third central area AC3 are equal. The number of reversing passage sections 18b in the first reversing area AT1 and the number of reversing passage sections 18b in the second reversing area AT2 are equal. This suppresses an uneven distribution of the gas supplied to the membrane electrode gas diffusion layer assembly 13 via the passages 18. The configuration thus prevents a premature reduction in the service life of the membrane electrode gas diffusion layer assembly 13 due to an uneven distribution of the gas flowing through the passage 18 to the membrane electrode gas diffusion layer assembly 13.

[0046] Each individual cell 11 of the fuel cell has the membrane electrode gas diffusion layer assembly 13 and the two separators 14, which sandwich the membrane electrode gas diffusion layer assembly 13 from the anode side and the cathode side and are reversed relative to each other from front to back. Furthermore, a cell stack is formed using the individual cells 11 as follows. Specifically, a cell stack is formed by stacking the individual cells 11 in the thickness direction. In each adjacent pair of individual cells 11 in such a cell stack, the separators 14 lie side by side, and sections corresponding to the bottoms 24 of the passages 18 between the ribs 19 are in contact with each other. In such a configuration, the ribs 19 in the body 15 of the separator 14 extend in a wave-like manner, so that the sections corresponding to the bottoms 24 of the passages 18 between the ribs 19 also extend in a wave-like manner.When such sections are in contact with each other, they extend in different directions. As a result, the sections do not interlock. Accordingly, when the cell stack is compacted in the stacking direction of the individual cell 11, a reduction in the surface pressure transmitted from the body 15 of the separator 14 to the membrane electrode gas diffusion layer assembly 13 is prevented, which would otherwise impair the power generation efficiency.

[0047] (6) As it turns out Fig. As can be seen in Figure 7, the sections corresponding to the bottoms 24 of the passages 18 between the ribs 19 extend in different directions when the adjacent separators 14 are brought into contact, even when the reverse passage sections 18b are formed as straight lines inclined with respect to the short sides of the body 15 of each separator 14. This prevents these sections from interlocking and suppresses a reduction in the surface pressure transferred from the body 15 to the membrane electrode gas diffusion layer assembly 13 when the cell stack is compacted towards the individual cells 11, thereby preventing a deterioration in power generation efficiency.However, if the reversal passage sections 18b are formed as straight lines inclined with respect to the short sides of the body 15 of the separator 14, sections of the channels 18 lacking reversal passage sections 18b become larger, as shown by the long dashed and double short dashed lines in . Fig. 7 is evident. This leads to a reduction in power generation efficiency.

[0048] In contrast, the reverse passage sections 18b, as can be seen from the Fig. 3 and Fig. As can be seen in section 4, it is wavy in shape, so that, unlike the one in Fig. In the case represented by the long lines and double short lines, there is no significant enlargement of the sections in which the channels 18 do not have reverse passage sections 18b. Accordingly, a reduction in power generation efficiency due to an enlargement of such sections is suppressed.

[0049] The embodiment described above can be modified as follows. The embodiment described above and the following modifications can be combined, provided that the combined modifications remain technically compatible.

[0050] Either one or both of the central passage sections 18a and the reverse passage sections 18b in passage 18 can be designed in such a way that they extend in a straight line.

[0051] The number of reversal passage sections 18b in the first reversal area AT1 may differ from the number of reversal passage sections 18b in the second reversal area AT2. In this case, the number of reversal passage sections 18b in either the first reversal area AT1 or the second reversal area AT2 may match the number of central passage sections 18a in the central areas AC1, AC2, and AC3.

[0052] The number of central passage sections 18a in the first central area AC1, the number of central passage sections 18a in the second central area AC2 and the number of central passage sections 18a in the third central area AC3 do not necessarily have to be the same.

[0053] The widths of the central passage sections 18a and the reverse passage sections 18b in the passages 18 do not necessarily have to be constant.

[0054] The number of reversing sections 18B in the first reversing area AT1 can only be one, or the number of reversing sections 18b in the second reversing area AT2 can only be one.

[0055] The examples above can be modified in form and detail without altering the spirit and scope of the claims and their equivalents. The examples serve only for description and not for limitation. The descriptions of the features in each example are to be considered applicable to similar features or aspects in other examples. Suitable results can be obtained by performing sequences in a different order and / or by combining components differently in a described system, architecture, device, or circuit and / or by replacing or supplementing them with other components or their equivalents. The scope of disclosure is not defined by the detailed description but by the claims and their equivalents. All variations within the scope of the claims and their equivalents are contained in the disclosure. QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] JP 2005 - 190 795A

[0002]

Claims

[1] Separator (14) for a fuel cell, comprising a rectangular plate-shaped body (15) which can be arranged on both sides in a thickness direction of a membrane electrode gas diffusion layer assembly (13), wherein the body (15) forms passages (18) through which gas flows between the body (15) and the membrane electrode gas diffusion layer assembly (13), the body (15) has central areas (AC1, AC2, AC3) and a reversal area (AT1, AT2), the central areas (AC1, AC2, AC3) extend along one side of the body (15) and are arranged in a direction in which another side of the body (15), which intersects the first side, extends, the reversal area (AT1, AT2) extends along the other side of the body (15) and is located at a position corresponding to the ends of adjacent central areas in a longitudinal direction, the passages (18) have: several central passage sections (18a) extending longitudinally through each central area, and a reversal passage section (18b) extending through the reversal area and connecting the central passage sections (18a) of adjacent central areas, the body (15) has several ribs (19) that project towards the membrane electrode gas diffusion layer assembly (13) in order to be in contact with the membrane electrode gas diffusion layer assembly (13), the passages (18) between the ribs (19) are formed, and the ribs (19) are formed such that two or more of the central passage sections (18a) are formed in each of the central areas and the reversal passage section (18b) is connected in the reversal area to two or more of the central passage sections (18a) in the corresponding central area. [2] Separator (14) for a fuel cell according to claim 1, wherein the ribs (19) in the body are designed such that the reverse passage section (18b) is one of several reverse passage sections (18b) in the reverse area. [3] Separator (14) for a fuel cell according to claim 1 or 2, wherein the ribs (19) are designed such that a width of each central passage section (18a) and a width of the reverse passage section (18b) in the passages (18) are constant. [4] Separator (14) for the fuel cell according to one of claims 1 to 3, wherein the central areas have a first central area (AC1), a second central area (AC2) and a third central area (AC3), the reversal area is one of several reversal areas that have a first reversal area (AT1) and a second reversal area (AT2), the first central area (AC1) and the second central area (AC2) are adjacent to each other and the reversal passage section (18b) in the first reversal area (AT1) connects the central passage sections (18a) of the first central area (AC1) and the central passage sections (18a) of the second central area (AC2) at one end in the longitudinal direction, the second central area (AC2) and the third central area (AC3) adjoin each other, and the reversal passage section (18b) in the second reversal area (AT2) connects the central passage sections (18a) of the second central area (AC2) and the central passage sections (18a) of the third central area (AC3) at another end in the longitudinal direction, and the ribs (19) are formed in such a way that a number of central passage sections (18a) in the first central area (AC1), a number of central passage sections (18a) in the second central area (AC2) and a number of central passage sections (18a) in the third central area (AC3) are equal, and a number of reversal passage sections (18b) in the first reversal area (AT1) and a number of reversal passage sections (18b) in the second reversal area (AT2) are equal. [5] Separator (14) for the fuel cell according to one of claims 1 to 4, wherein the ribs (19) are formed on the body (15) in such a way that they extend in a wave-like manner. [6] Single cell (11) for a fuel cell, comprising: a membrane electrode gas diffusion layer assembly (13); and two separators (14) sandwich-like enclosing the membrane electrode gas diffusion layer assembly (13) from opposite sides in one thickness direction, wherein the separators are reversed relative to each other from front to back, wherein Passages (18) through which gas flows are formed between the separator (14) and the membrane electrode gas diffusion layer assembly (13), the separator (14) has central areas (AC1, AC2, AC3) and a reversal area (AT1, AT2), the central areas (AC1, AC2, AC3) extend along one side of the separator (14) and are arranged in a direction in which another side of the separator (14) extends, intersecting the first side, the reversal area (AT1, AT2) extends along the other side of the separator (14) and is located at a position corresponding to the ends of adjacent central areas in the longitudinal direction, the passages (18) have: several central passage sections (18a) extending longitudinally through each central area, and a reversal passage section (18b) extending through the reversal area and connecting the central passage sections (18a) of adjacent central areas, the separator (14) has several ribs (19) that project towards the membrane electrode gas diffusion layer assembly (13) in order to be in contact with the membrane electrode gas diffusion layer assembly (13), the passages (18) between the ribs (19) are formed, and the ribs (19) are formed such that two or more of the central passage sections (18a) are formed in each of the central areas and the reversal passage section (18b) is connected in the reversal area to two or more of the central passage sections (18a) in the corresponding central area.

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