Fuel cell stack

Abstract

The fuel cell stack includes stacked unit cells. Each single battery comprises a power generation part and a pair of first separator and second separator. The first divider includes a first channel. The first channels each include a first reversal portion and a first overall portion. The second divider includes a second channel. The second channels each include a second reversal portion and a second overall portion. The first reversal portions of the first channels each extend to increase a flow resistance of the cooling medium flowing through a portion of the cooling medium flow region corresponding to the first reversal portions. The second reversal portions of the second channels each extend to increase a flow resistance of the cooling medium flowing through a portion of the cooling medium flow region corresponding to the second reversal portions.

Description

Technical Field

[0001] The present disclosure relates to a fuel cell stack having a plurality of unit cells stacked thereon. Background Art

[0002] For example, a typical single cell of a fuel cell stack is disclosed in Japanese Patent Publication No. 2006-147466. Each single cell includes an electrolyte membrane-electrode assembly, an anode-side metal separator, and a cathode-side metal separator. The anode-side metal separator and the cathode-side metal separator sandwich the electrolyte membrane-electrode assembly. The single cell is generally in the shape of a rectangular plate. An oxidant gas inlet hole for supplying an oxidant gas and a fuel gas outlet hole for discharging a fuel gas are formed at one edge in the long side direction of the single cell.

[0003] A fuel gas inlet hole for supplying fuel gas and an oxidant gas outlet hole for discharging oxidant gas are formed at the other edge in the long side direction of the single cell. A cooling medium inlet hole for supplying cooling medium is formed at one edge in the short side direction of the single cell. A cooling medium outlet hole for discharging cooling medium is formed at the other edge in the short side direction of the single cell.

[0004] On the surface of the anode side metal separator facing the electrolyte membrane-electrode assembly, a fuel gas channel is formed by the concave and convex of the complementary relationship. The fuel gas channel is connected to the fuel gas inlet hole and the fuel gas outlet hole. The fuel gas channel includes a wavy channel groove and an embossed portion. The fuel gas channel forms a serpentine channel as a whole, which has two rotating partition members spaced apart from each other in the short side direction and arranged in a zigzag shape in the long side direction. The fuel gas channel includes two rotating parts and an embossed portion configured for the two rotating parts.

[0005] On the surface of the cathode side metal separator facing the electrolyte membrane-electrode assembly, an oxidant gas channel is formed by concave and convex complementary relationships. The oxidant gas channel is connected to the oxidant gas inlet hole and the oxidant gas outlet hole. The oxidant gas channel includes a wavy channel groove and an embossed portion. The oxidant gas channel forms a serpentine channel as a whole, which has two rotating partition members spaced apart from each other in the short side direction and arranged in a zigzag shape in the long side direction. The oxidant gas channel includes two rotating parts and an embossed portion configured for the two rotating parts.

[0006] A cooling medium channel connected to the cooling medium inlet hole and the cooling medium outlet hole extends in the short side direction between the anode side metal separator of one of the two unit cells adjacent to each other in the stacking direction and the cathode side metal separator of the other of the two unit cells. That is, a cooling medium channel is formed between the fuel gas channel and the oxidant gas channel. The cooling medium flows through the cooling medium channel from the cooling medium inlet hole toward the cooling medium outlet hole.

[0007] In the above-mentioned fuel cell stack, the cooling medium flowing through the cooling medium channel is subjected to higher resistance in the portion of the cooling medium channel corresponding to the corrugated channel groove of the gas channel than in the portion of the cooling medium channel corresponding to the embossed portion of the gas channel. As a result, the cooling medium channel has a portion where the cooling medium flows easily and a portion where the cooling medium does not flow easily. This causes a significant change in the cooling effect of the cooling medium in the single cell. Summary of the invention

[0008] This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter.

[0009] In one general aspect, a fuel cell stack includes stacked single cells. Each of the single cells is plate-shaped and includes a power generation unit and a pair of first and second separators sandwiching the power generation unit. Each of the single cells includes: a fuel gas supply hole through which fuel gas is supplied; a fuel gas discharge hole through which the fuel gas is discharged; an oxidant gas supply hole through which oxidant gas is supplied; and an oxidant gas discharge hole through which the oxidant gas is discharged. The fuel gas supply hole is formed at a first end portion, which is one of the two ends in the first direction of the single cell. The fuel gas discharge hole is formed at a second end portion, which is the other of the two ends in the first direction of the single cell. The oxidant gas supply hole is formed at one of the first end portion and the second end portion in the first direction of the single cell. The oxidant gas discharge hole is formed at the other of the first end portion and the second end portion in the first direction of the single cell. Each of the single cells further includes: a cooling medium supply hole through which a cooling medium is supplied; and a cooling medium discharge hole through which the cooling medium is discharged. The cooling medium supply hole is formed at a first end portion, which is one of two ends of the single cell in a second direction orthogonal to the first direction. The cooling medium discharge hole is formed at a second end portion, which is the other of the two ends in the second direction of the single cell. The first separator includes concave and convex portions in a complementary relationship. The concave and convex portions form a first channel, which is used to supply the oxidant gas to one surface of the power generation unit from the oxidant gas supply hole to the oxidant gas discharge hole. The first channel serves as a tortuous channel in which the flow direction of the oxidant gas is reversed multiple times. Each of the first channels includes a first reversing portion for reversing the flow of the oxidant gas and a first overall portion different from the first reversing portion. The second separator includes concave and convex portions in a complementary relationship. The concave and convex portions form a second channel, which is used to supply the fuel gas to the other surface of the power generation unit from the fuel gas supply hole to the fuel gas discharge hole. The second channel serves as a tortuous channel in which the flow direction of the fuel gas is reversed multiple times. The second channels each include a second reversing portion for reversing the flow of the fuel gas and a second general portion different from the second reversing portion. A cooling medium flow region through which the cooling medium flows from the cooling medium supply hole to the cooling medium discharge hole is formed between the first separator of one of two unit cells adjacent to each other in the stacking direction and the second separator of the other of the two unit cells. At least a portion of the first general portion of the first channel or the second general portion of the second channel is a wavy portion extending in a wavy manner.The first reversal portions of the first channels are each extended to increase the flow resistance of the cooling medium flowing through the portion of the cooling medium flow area corresponding to the first reversal portion. The second reversal portions of the second channels are each extended to increase the flow resistance of the cooling medium flowing through the portion of the cooling medium flow area corresponding to the second reversal portion.

[0010] Other features and aspects will be apparent from the following detailed description, drawings, and claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 is a schematic cross-sectional view of a fuel cell according to an embodiment.

[0012] Figure 2 It is an exploded perspective view showing a single battery.

[0013] Figure 3 is a plan view of a fuel cell stack.

[0014] Figure 4 yes Figure 3 An enlarged partial view of .

[0015] Figure 5 2 is a cross-sectional view of the concavities and convexities forming the first channel of the first separator and the second channel of the second separator.

[0016] Figure 6 is a plan view showing the positional relationship between the first channel of the first separator and the second channel of the second separator in the fuel cell stack in the modification.

[0017] 7A to 7C : is a plan view showing an overlapping state of the first wave-shaped portion and the second wave-shaped portion in a modification.

[0018] Figure 8 is a plan view showing the positional relationship between the first channel of the first separator and the second channel of the second separator in the fuel cell stack in the modification.

[0019] Fig. 9 is a plan view showing the positional relationship between the first channel of the first separator and the second channel of the second separator in the fuel cell stack in the modification.

[0020] FIG. 10A to FIG. 10C is a plan view when the amplitudes of the first wavy portion and the second wavy portion are changed in the modification.

[0021] FIG. 11A to FIG. 11C is a plan view when the wavelengths of the first wavy portion and the second wavy portion are changed in the modification.

[0022] Fig.12 is a plan view of a first wavy portion and a second wavy portion in a variation.

[0023] FIG. 13A to FIG. 13E is a plan view of a first wavy portion and a second wavy portion in a variation.

[0024] In all drawings and detailed description, the same reference numerals refer to the same elements. The drawings may not be drawn to scale, and the relative size, proportion and depiction of elements in the drawings may be exaggerated for clarity, illustration and convenience. DETAILED DESCRIPTION

[0025] 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 will be apparent to those of ordinary skill in the art. The order of operations is exemplary and, except for operations that must occur in a certain order, may be varied as will be apparent to those of ordinary skill in the art. Descriptions of functions and configurations that are well known to those of ordinary skill in the art may be omitted.

[0026] Example embodiments may have different forms and are not limited to the described examples. However, the described examples are thorough and complete, and convey the full scope of the disclosure to those skilled in the art.

[0027] In the present specification, “at least one of A and B” should be understood to mean “only A, only B, or both A and B”.

[0028] Embodiments will now be described with reference to the accompanying drawings.

[0029] Fuel Cell 11

[0030] like Figure 1 As shown, the fuel cell 11 includes a fuel cell stack 13 and two end plates 14. The fuel cell stack 13 includes rectangular plate-shaped single cells 12 for generating electricity. The single cells 12 are stacked in the thickness direction Z, and the two end plates 14 sandwich the fuel cell stack 13 on the opposite sides of the single cells 12 in the thickness direction Z (stacking direction).

[0031] The outer edges of the two end plates 14 are fastened to each other by bolts 15 and nuts 16, thereby pressurizing and compressing the fuel cell stack 13 in the thickness direction Z (stack direction) of the single cells 12. A terminal plate (not shown) for collecting current and an insulating plate (not shown) for insulation are arranged between each of the two end plates 14 and the fuel cell stack 13.

[0032] Single battery 12

[0033] like Figure 2As shown, the single cell 12 includes a rectangular sheet-shaped power generation unit 17, a rectangular plate-shaped support frame 18 supporting the power generation unit 17, two rectangular sheet-shaped gas diffusion layers 19 sandwiching the power generation unit 17, and two metal separators 20. The two separators 20 sandwich the support frame 18 supporting the power generation unit 17 sandwiched between the two gas diffusion layers 19.

[0034] One of the two separators 20 disposed on the cathode side is a first separator 21, and the other of the two separators 20 disposed on the anode side is a second separator 22. The power generation section 17 is supported while being accommodated in a rectangular opening 23 formed in the central portion of the support frame 18. The power generation section 17 is formed of a membrane electrode assembly (MEA).

[0035] In the following description, the long side direction, short side direction, and thickness direction of the unit battery 12 are respectively referred to as long side direction X as an example of a first direction, short side direction Y as an example of a second direction, and thickness direction Z. The long side direction X, short side direction Y, and thickness direction Z are orthogonal to each other.

[0036] Channel structure in the single cell 12

[0037] like Figure 2 and Figure 3 As shown, a fuel gas supply hole 24 and an oxidant gas discharge hole 25 are formed at a first end which is one of two ends located on opposite sides in the long side direction X of the power generation section 17 of the unit cell 12. An oxidant gas supply hole 26 and a fuel gas discharge hole 27 are formed at a second end which is the other of the two ends. The fuel gas supply hole 24 and the oxidant gas discharge hole 25 are elongated holes and are formed adjacent to each other in the short side direction Y.

[0038] The oxidant gas supply hole 26 and the fuel gas discharge hole 27 are elongated holes and are formed adjacent to each other in the short side direction Y. The fuel gas supply hole 24 is supplied with a fuel gas containing, for example, hydrogen. The fuel gas discharge hole 27 discharges the fuel gas. The oxidant gas supply hole 26 is supplied with an oxidant gas containing, for example, oxygen. The oxidant gas discharge hole 25 discharges the oxidant gas.

[0039] The fuel gas supply holes 24 and the oxidant gas supply holes 26 are opposite to each other in the longitudinal direction X. The oxidant gas discharge holes 25 and the fuel gas discharge holes 27 are opposite to each other in the longitudinal direction X.

[0040] Two cooling medium supply holes 28 are formed at a first end, which is one of two ends located on opposite sides in the short-side direction Y of the power generation section 17 of the unit battery 12, and two cooling medium discharge holes 29 are formed at a second end, which is the other of the two ends. The two cooling medium supply holes 28 are elongated holes and are formed adjacent to each other in the long-side direction X. The two cooling medium discharge holes 29 are elongated holes and are formed adjacent to each other in the long-side direction X.

[0041] The two cooling medium supply holes 28 are supplied with a cooling medium such as a coolant. The two cooling medium discharge holes 29 discharge the cooling medium. The two cooling medium supply holes 28 and the two cooling medium discharge holes 29 are opposite to each other in the short side direction Y.

[0042] The fuel gas supply holes 24, fuel gas discharge holes 27, oxidant gas supply holes 26, oxidant gas discharge holes 25, cooling medium supply holes 28, and cooling medium discharge holes 29 of the single cells 12 are all formed as manifolds extending through the fuel cell stack 13 in the thickness direction Z (stacking direction).

[0043] Separator 20

[0044] like Figure 2 , Figure 3 and Figure 5 As shown, the first channel 30 connecting the oxidant gas supply hole 26 and the oxidant gas discharge hole 25 is arranged on the surface of the first separator 21 facing the power generation part 17. The first channel 30 through which the oxidant gas flows supplies the oxidant gas to one surface of the power generation part 17 from the oxidant gas supply hole 26 to the oxidant gas discharge hole 25. The first channel 30 is formed by concave and convex in a complementary relationship formed on opposite surfaces by pressurizing the first separator 21. In the present embodiment, the concave and convex of each first channel 30 forming the first separator 21 is a trapezoidal shape in a cross-sectional view.

[0045] The first channel 30 is formed by a concave portion 31 which is a part of the concave-convex of the first separator 21 and faces the power generation section 17. The concave portions 31 forming the first channel 30 extend in parallel at regular intervals. The convex portions 32 are formed between the concave portions 31 of the first separator 21. In the concave-convex of the first separator 21, the concave portion 31 in one surface forms the convex portion 32 in the other surface, and the convex portion 32 in one surface forms the concave portion 31 in the other surface.

[0046] The concavoconvex arrangement in the first partition 21 is such that the concave portions 31 and the convex portions 32 are alternately arranged at equal intervals in the arrangement direction of the first channel 30. The first channel 30 in the first partition 21 extends in a zigzag manner so that the flow direction of the oxidant gas is reversed multiple times (twice in this example). In other words, the first channel 30 is a serpentine channel.

[0047] like Figure 2 , Figure 3 and Figure 5 As shown, the second channel 33 connecting the fuel gas supply hole 24 and the fuel gas discharge hole 27 is arranged on the surface of the second separator 22 facing the power generation part 17. The second channel 33 through which the fuel gas flows supplies the fuel gas from the fuel gas supply hole 24 to the fuel gas discharge hole 27 to the other surface of the power generation part 17 opposite to the first separator 21. The second channel 33 is formed by the concave and convex of the complementary relationship formed on the opposite surface by pressurizing the second separator 22. In the present embodiment, the concave and convex of each second channel 33 forming the second separator 22 is a trapezoidal shape in a cross-sectional view.

[0048] The second channel 33 is formed by the recessed portion 31 which is a part of the recessed and convex of the second separator 22 and faces the power generation section 17. The recessed portions 31 forming the second channel 33 extend in parallel at regular intervals. The convex portions 32 are formed between the recessed portions 31 of the second separator 22. In the recessed and convex of the second separator 22, the recessed portion 31 in one surface forms the convex portion 32 in the other surface, and the convex portion 32 in one surface forms the recessed portion 31 in the other surface.

[0049] The concavoconvex arrangement in the second separator 22 is such that the concave portions 31 and the convex portions 32 are alternately arranged at equal intervals in the arrangement direction of the second channel 33. The second channel 33 in the second separator 22 extends in a zigzag manner so that the flow direction of the fuel gas is reversed multiple times (twice in this example). In other words, the second channel 33 is a serpentine channel.

[0050] like Figures 2 to 4 As shown, the first separator 21 and the second separator 22 have the same configuration. In the single cell 12, the first separator 21 and the second separator 22 are configured so that one of the separators is reversed relative to the other. In this case, when the first separator 21 and the second separator 22 are viewed along the thickness direction Z, the fuel gas supply hole 24, the fuel gas discharge hole 27, the oxidant gas supply hole 26, the oxidant gas discharge hole 25, the two cooling medium supply holes 28, and the two cooling medium discharge holes 29 overlap with each other.

[0051] Fuel cell stack 13

[0052] like Figures 1 to 4As shown, the cooling medium flow area 34 through which the cooling medium flows from the cooling medium supply hole 28 to the cooling medium discharge hole 29 is formed between the first separator 21 of one of the two single cells 12 adjacent to each other in the thickness direction Z (stacking direction) in the fuel cell stack 13 and the second separator 22 of the other of the two single cells 12. Thus, the flow direction F of the cooling medium in the cooling medium flow area 34 is a direction extending from the cooling medium supply hole 28 toward the cooling medium discharge hole 29 and extending parallel to the short side direction Y.

[0053] The cooling medium flow area 34 contacts the concavo-convex of the first channel 30 forming the first partition 21 and the concavo-convex of the second channel 33 forming the second partition 22. Thus, the concavo-convex of the first channel 30 forming the first partition 21 and the concavo-convex of the second channel 33 forming the second partition 22 affect the cooling medium flowing in the cooling medium flow area 34.

[0054] In each first channel 30 of the first separator 21 , a portion for reversing the flow of the oxidant gas is referred to as a first reversing portion 35 , and a portion different from the first reversing portion 35 is referred to as a first overall portion 36 .

[0055] The first reversal portion 35 is straight and extends obliquely with respect to the flow direction F of the cooling medium to increase the flow resistance of the cooling medium flowing through the portion of the cooling medium flow area 34 corresponding to the first reversal portion 35. The first overall portion 36 extends in the long side direction X. The first overall portion 36 is a first wavy portion 37 as a whole as an example of a wavy portion extending in a wavy manner.

[0056] In each second channel 33 of the second separator 22 , a portion for reversing the flow of the fuel gas is referred to as a second reversing portion 38 , and a portion different from the second reversing portion 38 is referred to as a second overall portion 39 .

[0057] The second reversal portion 38 is straight and extends obliquely with respect to the flow direction F of the cooling medium to increase the flow resistance of the cooling medium flowing through the portion of the cooling medium flow area 34 corresponding to the second reversal portion 38. The second overall portion 39 extends in the long side direction X. The second overall portion 39 is a second wavy portion 40 as a whole as an example of a wavy portion extending in a wavy manner.

[0058] When the first and second separators 21 and 22 are stacked in the thickness direction Z (stacking direction), the phases of the first wavy portion 37 of the first general portion 36 of each first channel 30 and the second wavy portion 40 of the second general portion 39 of each second channel 33 are offset from each other.

[0059] In the first partition 21 and the second partition 22, the first channel 30 of the first partition 21 and the second channel 33 of the second partition 22 extend across each other when viewed in the thickness direction Z. In this case, the first channel 30 of the first partition 21 and the second channel 33 of the second partition 22 do not overlap at all in a configuration parallel to each other in the thickness direction Z.

[0060] Operation of Embodiments

[0061] like Figures 1 to 4 As shown, when the fuel cell 11 is supplied with oxidant gas, fuel gas and cooling medium, the single cells 12 of the fuel cell stack 13 generate electricity. When the single cells 12 generate electricity, oxidant gas is supplied from the oxidant gas supply hole 26 and fuel gas is supplied from the fuel gas supply hole 24.

[0062] When the oxidant gas is supplied from the oxidant gas supply holes 26 in the unit cells 12, the oxidant gas is supplied to the cathode side surface of the power generation section 17 while being diffused by the gas diffusion layer 19 in the process of flowing to the oxidant gas discharge holes 25 through each first channel 30. The oxidant gas flowing into the oxidant gas discharge holes 25 is discharged from the fuel cell stack 13.

[0063] When the fuel gas is supplied from the fuel gas supply holes 24 in the unit cells 12, the fuel gas is supplied to the anode side surface of the power generation section 17 while being diffused by the gas diffusion layer 19 in the process of flowing to the fuel gas exhaust holes 27 through the second channels 33. The fuel gas flowing into the fuel gas exhaust holes 27 is discharged from the fuel cell stack 13.

[0064] In this case, the unit cells 12 each generate electricity based on an electrochemical reaction in the power generation section 17 between the oxidant gas supplied to the cathode side surface of the power generation section 17 and the fuel gas supplied to the anode side surface of the power generation section 17 .

[0065] Due to the power generation through the electrochemical reaction, the single cells 12 all generate heat. In view of this, in the cooling medium flow area 34 formed between the first separator 21 of one of the two single cells 12 adjacent to each other in the fuel cell stack 13 and the second separator 22 of the other of the two single cells 12, the cooling medium flows from the cooling medium supply hole 28 to the cooling medium discharge hole 29. This cools the single cells 12. The cooling medium that flows into the cooling medium discharge hole 29 is discharged from the fuel cell stack 13.

[0066] In this case, generally speaking, the concavo-convex portions of the first channel 30 forming the first partition 21 and the second channel 33 forming the second partition 22 are in a complementary relationship. Thus, when the cooling medium flows through the cooling medium flow region 34, the concavo-convex portions act as flow resistance. Since the first channel 30 and the second channel 33 are zigzag channels, the first overall portion 36 and the second overall portion 39 generally extend orthogonally to the flow direction F of the cooling medium, and the first reversal portion 35 and the second reversal portion 38 extend along the flow direction F of the cooling medium.

[0067] Thus, the flow resistance when the cooling medium flows through the cooling medium flow area 34 is greater in the portion corresponding to the first general portion 36 and the second general portion 39 of the cooling medium flow area 34 than in the portion corresponding to the first reversal portion 35 and the second reversal portion 38 of the cooling medium flow area 34. Thus, the cooling medium flow area 34 has a portion where the cooling medium easily flows and a portion where the cooling medium does not easily flow. This causes the cooling effect of the cooling medium in the single battery 12 to vary.

[0068] In this regard, in the present embodiment, the first reversal portion 35 of the first channel 30 extends obliquely relative to the flow direction F of the cooling medium to increase the flow resistance of the cooling medium flowing through the portion of the cooling medium flow area 34 corresponding to the first reversal portion 35. In addition, the second reversal portion 38 of the second channel 33 extends obliquely relative to the flow direction F of the cooling medium to increase the flow resistance of the cooling medium flowing through the portion of the cooling medium flow area 34 corresponding to the second reversal portion 38.

[0069] As a result, the difference in flow resistance when the cooling medium flows between the portion of the cooling medium flow region 34 corresponding to the first reversal portion 35 and the second reversal portion 38 and the portion of the cooling medium flow region 34 corresponding to the first overall portion 36 and the second overall portion 39 is reduced. The cooling medium flows through the cooling medium flow region 34 in a balanced manner, thereby reducing the variation in the cooling effect of the cooling medium in the single battery 12.

[0070] Advantages of the implementation method

[0071] The above-mentioned embodiment has the following advantages.

[0072] (1) In the fuel cell stack 13, the first reversing portion 35 of the first channel 30 extends obliquely with respect to the flow direction F of the cooling medium to increase the flow resistance of the cooling medium flowing through the portion of the cooling medium flow area 34 corresponding to the first reversing portion 35. In addition, the second reversing portion 38 of the second channel 33 extends obliquely with respect to the flow direction F of the cooling medium to increase the flow resistance of the cooling medium flowing through the portion of the cooling medium flow area 34 corresponding to the second reversing portion 38.

[0073] By the above configuration, the difference in flow resistance when the cooling medium flows between the portion of the cooling medium flow region 34 corresponding to the first reversal portion 35 and the second reversal portion 38 and the portion of the cooling medium flow region 34 corresponding to the first overall portion 36 and the second overall portion 39 is reduced. The cooling medium flows through the cooling medium flow region 34 in a balanced manner, thereby reducing the variation in the cooling effect of the cooling medium in the single battery 12.

[0074] (2) In the fuel cell stack 13, the first overall portion 36 of the first channel 30 and the second overall portion 39 of the second channel 33 are respectively the first wavy portion 37 and the second wavy portion 40 as a whole. When the first separator 21 and the second separator 22 are stacked, the phase of the first wavy portion 37 of the first channel 30 and the phase of the second wavy portion 40 of the second channel 33 are offset from each other.

[0075] Through the above construction, the phase of the first wavy portion 37 of the first channel 30 is offset from the phase of the second wavy portion 40 of the second channel 33, which changes the flow resistance of the flowing medium flowing through the cooling medium flow area 34 corresponding to the first overall portion 36 of the first channel 30 and the second overall portion 39 of the second channel 33 compared to when the phases are not offset.

[0076] (3) In the fuel cell stack 13, the first separator 21 and the second separator 22 have the same configuration.

[0077] Through the above configuration, the first partition 21 and the second partition 22 may be the same component, and the number of components may be reduced compared to when the first partition 21 and the second partition 22 are different components.

[0078] (4) When viewed from the thickness direction Z, in the first separator 21 and the second separator 22 of the fuel cell stack 13, the first channel 30 of the first separator 21 and the second channel 33 of the second separator 22 extend across each other. In this case, the first channel 30 of the first separator 21 and the second channel 33 of the second separator 22 do not overlap at all in a configuration parallel to each other in the thickness direction Z.

[0079] By the above configuration, when the single cells 12 are stacked to form the fuel cell stack 13, the first channel 30 of the first separator 21 and the second channel 33 of the second separator 22 directly overlap and intersect each other. Even if there is a slight displacement in the position where the concave and convex overlap, this configuration avoids the concave and convex fitting into each other. This applies to the first separator 21 in which the first channel 30 is formed by the concave and convex in a complementary relationship and the second separator 22 in which the second channel 33 is formed by the concave and convex in a complementary relationship. Thus, although the first separator 21 and the second separator 22 have the same configuration, when the fuel cell stack 13 is formed by stacking the single cells 12, the plane pressure between the single cells 12 is ensured. This will maintain the power generation performance of the fuel cell 11.

[0080] When the concavoconvex in a complementary relationship forming the first channel 30 of the first separator 21 is fitted into the concavoconvex in a complementary relationship forming the second channel 33 of the second separator 22, the stacking thickness of the single cell 12 at the fitting portion is reduced. As a result, when the single cells 12 are stacked to form the fuel cell stack 13, the plane pressure between the single cells 12 is not ensured. This will deteriorate the power generation performance of the fuel cell 11.

[0081] Variants

[0082] The above-mentioned embodiment can be modified as follows. The above-mentioned embodiment and the following modifications can be combined as long as the combined modifications are technically consistent with each other.

[0083] like Figure 6 As shown, the first reversal portion 35 of the first channel 30 and the second reversal portion 38 of the second channel 33 may extend in a wavy manner. This will further increase the flow resistance of the cooling medium flowing through the portion of the cooling medium flow area 34 corresponding to the first reversal portion 35 and the second reversal portion 38. As a result, the difference in flow resistance when the cooling medium flows between the portion of the cooling medium flow area 34 corresponding to the first reversal portion 35 and the second reversal portion 38 and the portion of the cooling medium flow area 34 corresponding to the first overall portion 36 and the second overall portion 39 is further reduced.

[0084] exist Figure 6 In the case of the first reversal portion 35 of the first channel 30 and the second reversal portion 38 of the second channel 33, the first reversal portion 35 of the first channel 30 and the second reversal portion 38 of the second channel 33 may extend in parallel with the flow direction F of the cooling medium in the cooling medium flow area 34. This will further increase the flow resistance of the cooling medium flowing through the portion corresponding to the first reversal portion 35 and the second reversal portion 38 of the cooling medium flow area 34, compared to when the first reversal portion 35 of the first channel 30 and the second reversal portion 38 of the second channel 33 are straight.

[0085] exist Figure 6In this case, the amplitudes of the wavy first reversal portion 35 and the wavy second reversal portion 38 may be greater than or less than the amplitudes of the first wavy portion 37 and the second wavy portion 40 .

[0086] exist Figure 6 In this case, the wavelengths of the wavy first reversal portion 35 and the wavy second reversal portion 38 may be larger or smaller than the wavelengths of the first wavy portion 37 and the second wavy portion 40 .

[0087] like Fig. 7A As shown, the phase of the first wavy portion 37 of the first channel 30 and the phase of the second wavy portion 40 of the second channel 33 may be offset by half a pitch.

[0088] like Figure 7B As shown, the phase of the first wave portion 37 of the first channel 30 and the phase of the second wave portion 40 of the second channel 33 may be offset by a quarter pitch.

[0089] like Figure 7C As shown, the phase of the first undulating portion 37 of the first channel 30 and the phase of the second undulating portion 40 of the second channel 33 may be offset by one-third of the pitch.

[0090] like Figure 8 As shown, a half (a portion) of the first overall portion 36 of the first passage 30 and a half (a portion) of the second overall portion 39 of the second passage 33 may be in a straight shape.

[0091] like Fig. 9 As shown, Figure 8 The straight portion of the first overall portion 36 of the first channel 30 and the straight portion of the second overall portion 39 of the second channel 33 may extend obliquely with respect to the longitudinal direction X.

[0092] like Fig. 10A , Fig. 10B and Fig. 10C As shown, the amplitudes of the first wavy portion 37 and the second wavy portion 40 can be varied. Fig. 10A , Fig. 10B and Fig. 10C In the embodiment, the amplitudes of the first wavy portion 37 and the second wavy portion 40 are Fig. 10A The smallest and Fig. 10C The largest.

[0093] like Fig.11A , Fig. 11B and Fig. 11C As shown, the wavelengths of the first wavy portion 37 and the second wavy portion 40 can be changed. Fig.11A , Fig. 11B and Fig. 11C In the embodiment, the wavelengths of the first wavy portion 37 and the second wavy portion 40 are Fig.11A The longest and Fig. 11C The shortest among them.

[0094] like Fig.12 As shown, the amplitudes of the first wavy portion 37 and the second wavy portion 40 may gradually decrease or increase.

[0095] like Fig.13A As shown, the first wavy portion 37 and the second wavy portion 40 may be trapezoidal in shape.

[0096] like Fig. 13B As shown, the first wavy portion 37 and the second wavy portion 40 may be in a zigzag shape.

[0097] like Fig. 13C As shown, the first wavy portion 37 and the second wavy portion 40 may be V-shaped.

[0098] like Fig.13D As shown, the first wavy portion 37 and the second wavy portion 40 may be W-shaped.

[0099] like Fig.13E As shown, the first and second wavy portions 37 and 40 may be zigzag shaped such that narrower narrow portions 41 and wider portions 42 than the narrow portions 41 are alternately arranged. This allows the oxidant gas and the fuel gas to easily enter the gas diffusion layer 19 from the first and second wavy portions 37 and 40.

[0100] FIG. 13A to FIG. 13E The shape can be applied to Figure 6 The first reversal portion 35 and the second reversal portion 38 in the embodiment.

[0101] The first separator 21 and the second separator 22 may have different configurations from each other.

[0102] The first general portion 36 of the first channel 30 and the second general portion 39 of the second channel 33 may be partially the first wavy portion 37 and the second wavy portion 40, respectively. When the first and second separators 21 and 22 are stacked, the phases of the first wavy portion 37 of the first channel 30 and the second wavy portion 40 of the second channel 33 do not need to be offset from each other.

[0103] The first general portion 36 of the first passage 30 or the second general portion 39 of the second passage 33 may be in a straight shape.

[0104] The position of the oxidant gas discharge hole 25 and the position of the oxidant gas supply hole 26 may be interchanged.

[0105] The position of the fuel gas supply hole 24 and the position of the fuel gas discharge hole 27 may be interchanged.

[0106] Various changes in form and detail may be made to the above examples without departing from the spirit and scope of the claims and their equivalents. The examples are for ease of illustration only and not for the purpose of limitation. The description of the features in each example should be considered to apply to the same features or aspects in other examples. If the sequence is performed in a different order, and / or if the components in the system, architecture, device or circuit are combined differently and / or replaced or supplemented by other components or their equivalents, suitable results can be achieved. The scope of the present disclosure is not limited by the specific embodiments, but by the claims and their equivalents. All modifications within the scope of the claims and their equivalents are included in the present disclosure.

Claims

1. A fuel cell stack, comprising: The stacked single cells are each plate-shaped and include a power generation portion and a pair of first and second separators sandwiching the power generation portion, wherein: The single cells all include: a fuel gas supply hole through which fuel gas is supplied; a fuel gas discharge hole through which the fuel gas is discharged; an oxidant gas supply hole through which the oxidant gas is supplied; and an oxidant gas discharge hole through which the oxidant gas is discharged; The fuel gas supply hole is formed at a first end portion which is one of two ends of the unit cell in a first direction; The fuel gas discharge hole is formed at a second end portion which is the other of the two ends of the unit cell in the first direction; The oxidant gas supply hole is formed at one of the first end and the second end of the unit cell in the first direction; The oxidant gas discharge hole is formed at the other of the first end and the second end of the unit cell in the first direction, The single cells also include: a cooling medium supply hole through which a cooling medium is supplied; and a cooling medium discharge hole through which the cooling medium is discharged; The cooling medium supply hole is formed at a first end portion which is one of two ends of the unit battery in a second direction orthogonal to the first direction; The cooling medium discharge hole is formed at a second end portion which is the other of the two ends of the unit battery in the second direction; The first separator includes concave and convex parts in a complementary relationship, the concave and convex parts forming a first channel for supplying the oxidant gas to one surface of the power generation portion from the oxidant gas supply hole to the oxidant gas discharge hole, the first channel serving as a tortuous channel in which the flow direction of the oxidant gas is reversed multiple times, The first channels each include a first reversing portion for reversing the flow of the oxidant gas and a first overall portion different from the first reversing portion; The second separator includes concave and convex parts in a complementary relationship, the concave and convex parts forming a second channel for supplying the fuel gas to the other surface of the power generation part from the fuel gas supply hole to the fuel gas discharge hole, the second channel serving as a tortuous channel in which the flow direction of the fuel gas is reversed multiple times, The second channels each include a second reversing portion for reversing the flow of the fuel gas and a second overall portion different from the second reversing portion, A cooling medium flow area through which the cooling medium flows from the cooling medium supply hole to the cooling medium discharge hole is formed between the first separator of one of two unit batteries adjacent to each other in the stacking direction and the second separator of the other of the two unit batteries, and at least a portion of a first overall portion of the first channel or a second overall portion of the second channel is a wavy portion extending in a wavy manner. The first reversal portions of the first channels are each extended to increase the flow resistance of the cooling medium flowing through a portion of the cooling medium flow region corresponding to the first reversal portion, and The second reversing portions of the second channels are each extended to increase the flow resistance of the cooling medium flowing through a portion of the cooling medium flow region corresponding to the second reversing portion.

2. The fuel cell stack according to claim 1, wherein: The first reversing portion and the second reversing portion extend obliquely with respect to a flow direction of the coolant in the coolant flow region.

3. The fuel cell stack according to claim 1, wherein: The first reverse portion and the second reverse portion extend in a wave-like manner.

4. The fuel cell stack according to claim 1, wherein: The first general portion of the first channel and the second general portion of the second channel as a whole are the wavy portion, and When the first separator and the second separator are stacked, a phase of the wavy portion of the first channel and a phase of the wavy portion of the second channel are offset from each other.

5. The fuel cell stack according to any one of claims 1 to 4, wherein: The first partition and the second partition have the same configuration.

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