JP2006260917A - Fuel cell and fuel cell stack - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To adjust flow of coolant in a coolant flow passage with simple construction, and to uniformize temperature distribution on a power generation face. <P>SOLUTION: A coolant flow passage 42 and a coolant inlet communication hole 22a are communicated with each other through two inlet buffer parts 44, 62. A pressure loss generation part 80a restraining the flow of coolant is arranged at least to the inlet buffer part 44 out of inlet buffer parts 44, 62. The pressure loss generation part 80a is provided with a pressure loss element 82a which can be attached to and detached from the inlet buffer part 44. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a fuel cell and a fuel cell stack having an electrolyte / electrode structure configured by sandwiching an electrolyte between a pair of electrodes, and alternately stacking the electrolyte / electrode structure and a separator.

  For example, a solid polymer fuel cell employs a solid polymer electrolyte membrane made of a polymer ion exchange membrane. In this fuel cell, an electrolyte membrane / electrode structure (electrolyte / electrode structure) in which an anode side electrode and a cathode side electrode each made of an electrode catalyst and porous carbon are provided on both sides of a solid polymer electrolyte membrane is separated into a separator. It is configured by being sandwiched between (bipolar plates). Usually, a fuel cell stack in which a predetermined number of the fuel cells are stacked is used.

  In the above fuel cell, a fuel gas channel (reactive gas channel) for flowing a fuel gas opposite to the anode side electrode and an oxidant gas for flowing the cathode gas facing the cathode side electrode in the plane of the separator. The oxidant gas flow path (reaction gas flow path) is provided. Furthermore, between the separators, a cooling medium flow path for flowing the cooling medium is provided along the surface direction of the separator.

  As this type of separator, a carbon separator composed of a carbon-based material or a metal separator composed of a metal plate is usually used. In this case, particularly in the case of a metal separator, when the flow path shape of the reaction gas flow path is set by pressing, the cooling medium flow path is inevitably determined on the back side of the reaction gas flow path. Will be formed.

  For this reason, for example, if the reaction gas flow path is composed of a serpentine flow path, the flow path shape of the cooling medium flow path is significantly limited, making it difficult to cool the electrode surface uniformly and obtain stable power generation performance. There is a problem of becoming.

  Therefore, for example, in the fuel cell disclosed in Patent Document 1, two or more inlet buffer portions in which the cooling medium flow path communicates with the cooling medium inlet communication hole via the inlet connection flow path, and the cooling medium outlet communication hole. Two or more outlet buffer portions communicating with each other through the outlet connecting flow path are provided. The first and second inlet buffer channels communicating the first and second inlet buffer portions with the cooling medium inlet communication hole are different from each other in the number of the first and second outlet buffer portions. The first and second outlet connection channels that communicate with the cooling medium outlet communication hole are set to have different numbers of channels.

  As a result, the cooling medium does not cancel out the pressure in the cooling medium flow path, can ensure a desired flow velocity and a desired flow state, and can flow uniformly in the separator surface. For this reason, the whole electrode surface can be cooled uniformly and stable power generation performance can be obtained.

Japanese Patent Laying-Open No. 2004-171824 (FIG. 4)

  By the way, in the fuel cell, a high concentration of oxidant gas or fuel gas (hereinafter also referred to as reaction gas) is supplied on the inlet side of the reaction gas flow path. On the other hand, on the outlet side of the reaction gas flow path, the power generation capacity is lowered due to the decrease in the reaction gas concentration, and condensed water is likely to be generated.

  For this reason, the electrolyte membrane / electrode structure becomes high temperature on the upstream side of the reaction gas flow path, and an increase in electrical resistance is likely to occur, and condensed water stays on the downstream side of the reaction gas flow path. Therefore, there is a problem that wastewater treatment is not performed reliably.

  The present invention solves this type of problem, and can adjust the flow of the cooling medium in the cooling medium flow path with a simple configuration, and can make the temperature distribution in the power generation surface uniform. An object is to provide a battery.

  Further, according to the present invention, in a stack in which a plurality of fuel cells are stacked, the flow rate of the cooling medium is adjusted favorably with a simple configuration between the fuel cell at the stacking direction end and the fuel cell at the stacking center. It is an object of the present invention to provide a fuel cell stack that can be used.

  The present invention includes an electrolyte / electrode structure in which an electrolyte is sandwiched between a pair of electrodes, the electrolyte / electrode structure is sandwiched between first and second separators, and penetrates in a stacking direction to communicate with a reaction gas inlet, A reaction gas outlet communication hole, a cooling medium inlet communication hole, and a cooling medium outlet communication hole are formed, and the cooling medium inlet communication hole and the cooling medium outlet communication hole are provided between the first and second separators stacked on each other. This is a fuel cell in which a cooling medium flow path communicating with the fuel cell is formed.

  The cooling medium flow path communicates with the cooling medium inlet communication hole via at least two inlet buffer portions, and at least the inlet buffer portion close to the reaction gas outlet communication hole among the two inlet buffer portions is cooled. A pressure loss generation unit that suppresses the flow of the medium is provided.

  Moreover, it is preferable that the inlet buffer part has embossing, and the pressure loss generation | occurrence | production part is provided with the pressure loss element which can be attached or detached to the said embossing. Furthermore, it is preferable that the pressure loss generating portion includes at least two types of pressure loss elements having different sizes, and the size of the pressure loss element is selected according to the inlet buffer portion.

  Furthermore, in the fuel cell stack according to the present invention, the cooling medium flow path communicates with the cooling medium inlet communication hole via at least two inlet buffer portions, and at least the reaction gas outlet in the two inlet buffer portions. The inlet buffer near the communication hole is provided with a pressure loss generating part that suppresses the flow of the cooling medium, and the pressure loss generating part of the fuel cell on the end side in the stacking direction The dimension is set to be larger than the part.

  In the fuel cell according to the present invention, the flow of the cooling medium is suppressed in the inlet buffer portion close to the reactive gas outlet communication hole via the pressure loss generating portion. For this reason, in the reaction gas flow path, the power generation capacity is likely to be reduced, that is, the temperature on the downstream side (in the vicinity of the reaction gas outlet communication hole) where condensation water is easily generated rises and the reaction gas is warmed. Condensed water or the like in the gas flow path is steamed and taken into the reaction gas. Thereby, it is possible to suppress the condensate from staying in the reaction gas flow path, and to reliably perform good wastewater treatment.

  On the other hand, the other inlet buffer section is close to the reaction gas inlet communication hole, and the flow rate of the cooling medium increases in the other inlet buffer section. Therefore, in the reaction gas flow path, the amount of the cooling medium supplied to the upstream side (in the vicinity of the reaction gas inlet communication hole) where the reaction tends to concentrate is increased, and the upstream side can be effectively cooled. For this reason, it becomes possible to prevent the electrolyte from becoming high temperature and perform stable power generation.

  Further, in the fuel cell stack according to the present invention, the pressure loss generation part of the fuel cell on the end side in the stacking direction is set to a size larger than the pressure loss generation part of the fuel cell on the center side in the stacking direction. Here, the fuel cell on the end side in the stacking direction tends to be at a lower temperature than the fuel cell on the center side in the stacking direction due to heat radiation or the like.

  In this case, in the present invention, the flow rate of the cooling medium supplied to the fuel cell at the stacking direction end is changed to the cooling supplied to the fuel cell at the stacking center by simply selecting the size of the pressure loss generating portion. It can be set smaller than the flow rate of the medium. As a result, the fuel cell on the end side in the stacking direction can prevent an increase in concentration overvoltage or a decrease in catalyst activity due to condensation, and the fuel cell stack as a whole can efficiently generate power.

  FIG. 1 is an exploded perspective view of a main part of a fuel cell 10 according to a first embodiment of the present invention, and FIG. 2 is a partial cross-sectional explanatory view of a fuel cell stack 11 in which the fuel cells 10 are stacked.

  The fuel cell 10 is configured by alternately laminating electrolyte membrane / electrode structures (electrolyte / electrode structures) 12 and separators 13, and the separators 13 are first and second metal plates that are laminated to each other. (First and second separators) 14 and 16 are provided.

  As shown in FIG. 1, an oxidant gas (reactive gas), for example, an oxygen-containing gas is supplied to one end edge of the fuel cell 10 in the arrow B direction so as to communicate with each other in the direction of arrow A, which is the stacking direction. An oxidant gas inlet communication hole (reactive gas inlet communication hole) 20a for supplying a coolant, a cooling medium inlet communication hole 22a for supplying a cooling medium, and a fuel gas (reactive gas), for example, a fuel for discharging a hydrogen-containing gas Gas outlet communication holes (reactive gas outlet communication holes) 24b are arranged in the direction of arrow C (vertical direction).

  The other end edge of the fuel cell 10 in the direction of arrow B communicates with each other in the direction of arrow A, discharges a fuel gas inlet communication hole (reactive gas inlet communication hole) 24a for supplying fuel gas, and discharges the cooling medium. A cooling medium outlet communication hole 22b for the purpose and an oxidant gas outlet communication hole (reaction gas outlet communication hole) 20b for discharging the oxidant gas are arranged in the direction of arrow C.

  As shown in FIGS. 1 and 2, the electrolyte membrane / electrode structure 12 includes, for example, a solid polymer electrolyte membrane (electrolyte) 26 in which a perfluorosulfonic acid thin film is impregnated with water, and the solid polymer electrolyte membrane. 26, an anode side electrode 28 and a cathode side electrode 30 sandwiching 26 are provided. The anode side electrode 28 is set to have a smaller surface area than the cathode side electrode 30, and the cathode side electrode 30 is provided so as to cover the entire surface of the solid polymer electrolyte membrane 26 (so-called step MEA).

  The anode side electrode 28 and the cathode side electrode 30 are uniformly coated on the surface of the gas diffusion layer with a gas diffusion layer (not shown) made of carbon paper or the like and porous carbon particles carrying a platinum alloy on the surface. And an electrode catalyst layer (not shown). The electrode catalyst layers are formed on both surfaces of the solid polymer electrolyte membrane 26.

  As shown in FIGS. 1 and 3, an oxidant gas flow path 32 is provided on the surface 14a of the first metal plate 14 facing the electrolyte membrane / electrode structure 12, and the oxidant gas flow path 32 is The oxidant gas inlet communication hole 20a communicates with the oxidant gas outlet communication hole 20b. The oxidant gas flow path 32 has a substantially right triangle inlet buffer 34 provided in the vicinity of the oxidant gas inlet communication hole 20a and a substantially right triangle in the shape of the oxidant gas outlet communication hole 20b. And an outlet buffer unit 36.

  The inlet buffer unit 34 and the outlet buffer unit 36 have a plurality of embosses 34 a and 36 a and communicate with each other through a plurality of oxidant gas flow channel grooves 32 a constituting the oxidant gas flow channel 32. The oxidant gas flow path 32 constitutes a serpentine flow path having an even-numbered, for example, twice-folded portion in the surface 14a of the first metal plate 14.

  A planar seal 40a is provided on the surface 14a of the first metal plate 14 to seal the oxidant gas around the oxidant gas inlet communication hole 20a, the oxidant gas outlet communication hole 20b, and the oxidant gas flow path 32. It is done.

  Between the surfaces 14b, 16b of the first metal plate 14 and the second metal plate 16 facing each other, a cooling medium flow path 42 described later is integrally formed. As shown in FIG. 4, on the surface 14b of the first metal plate 14, as a back side shape of the oxidant gas flow channel 32 formed on the surface 14a side, a flow channel portion 42a which is a part of the cooling medium flow channel 42. Is formed in a serpentine shape.

  The surface 14b is connected to the cooling medium inlet communication hole 22a via, for example, a substantially right triangular inlet buffer 44 communicated via two inlet communication channels 43 and the cooling medium outlet communication hole 22b. A substantially right-angled triangular outlet buffer section 50 is provided which communicates via the outlet communication channel 48 of the book. The inlet buffer unit 44 and the outlet buffer unit 50 have a plurality of embosses 44a and 50a.

  A planar seal 40b is provided on the surface 14b of the first metal plate 14 to circulate the cooling medium inlet communication hole 22a, the cooling medium outlet communication hole 22b, and the cooling medium flow path 42 to seal the cooling medium. The planar seals 40a and 40b constitute a first seal member 40 that is integrally provided so as to cover the outer peripheral end of the first metal plate 14 (see FIG. 2).

  As shown in FIG. 5, a fuel gas flow path 52 is provided on the surface 16 a of the second metal plate 16 facing the electrolyte membrane / electrode structure 12. The fuel gas flow path 52 includes a substantially right triangular inlet buffer portion 54 provided close to the fuel gas inlet communication hole 24a and a substantially right triangular outlet buffer portion provided close to the fuel gas outlet communication hole 24b. 56.

  The inlet buffer unit 54 and the outlet buffer unit 56 have a plurality of embossments 54a and 56a, are configured to be substantially symmetrical with each other, and a plurality of fuels are provided in the vicinity of the inlet buffer unit 54 and the outlet buffer unit 56. A gas inlet hole 58a and a fuel gas outlet hole 58b are formed.

  The inlet buffer portion 54 and the outlet buffer portion 56 communicate with each other via a plurality of fuel gas flow channel grooves 52 a that constitute the fuel gas flow channel 52. The fuel gas flow path 52 constitutes a serpentine flow path having an even number of times, for example, twice, in the surface 16b of the second metal separator 16.

  As shown in FIG. 6, on the surface 16b of the second metal plate 16, a flow path portion 42b, which is a part of the cooling medium flow path 42, is formed on the surface 16b of the fuel gas flow path 52 formed on the surface 16a. It is formed into a shape. The surface 16b is connected to the cooling medium inlet communication hole 22a via, for example, a substantially right triangular inlet buffer 62 communicated via four inlet communication channels 60, and to the cooling medium outlet communication hole 22b. A substantially right-angled triangular outlet buffer section 66 is provided which communicates via the outlet communication channel 64. The inlet buffer 62 and the outlet buffer 66 have a plurality of embosses 62a and 66a.

  As shown in FIG. 7, when the first metal plate 14 and the second metal plate 16 are laminated, the cooling medium flow path 42 has a back side of the oxidant gas flow path 32 and a back side of the fuel gas flow path 52. Overlapping and forming integrally.

  As shown in FIG. 5, the second seal member 70 is integrally formed so as to cover the outer peripheral end of the second metal plate 16. The second seal member 70 includes an outer linear seal 72 provided on the surface 16a, and an inner linear seal 74 spaced inward from the outer linear seal 72 by a predetermined distance.

  The outer linear seal 72 circulates around the outer periphery of the electrolyte membrane / electrode structure 12 and is superposed on the planar seal 40a provided on the first metal plate 14, as shown in FIG. The inner linear seal 74 circulates around the anode side electrode 28 and contacts the outer peripheral edge of the solid polymer electrolyte membrane 26 to close the fuel gas flow path 52 (see FIG. 2).

  As shown in FIG. 6, the second seal member 70 includes a linear seal 76 provided on the surface 16 b, and a backing convex portion 78 provided at a predetermined distance inside the linear seal 76. Have The linear seal 76 constitutes a refrigerant seal that covers the cooling medium flow path 42 and seals the cooling medium. On the other hand, the convex portion 78 is provided at a position overlapping the inner linear seal 74 provided on the surface 16 a in the stacking direction, and functions as a backing that receives the sealing pressure in the stacking direction of the inner linear seal 74.

  As shown in FIG. 7, the cooling medium inlet communication hole 22a communicates with the two inlet buffer parts 44 and 62, and at least the inlet buffer part 44 close to the fuel gas outlet communication hole 24b has a flow of the cooling medium. A pressure loss generating portion 80a that suppresses the above is provided. The pressure loss generating portion 80a includes a pressure loss element 82a that is detachably attached to the emboss 44a.

  The pressure loss element 82a has a substantially right triangle shape corresponding to the shape of the inlet buffer portion 44, and is provided with an emboss 84a corresponding to the emboss 44a. The pressure loss element 82a is attached to the inlet buffer portion 44 and the embosses 44a and 84a overlap each other. Thereby, the flow of the cooling medium is prevented along the surface direction of the pressure loss element 82a, and the opening area of the inlet buffer portion 44 is substantially reduced.

  The inlet buffer unit 62 is provided with a pressure loss generating unit 80b as necessary. The pressure loss generating portion 80b includes a pressure drop element 82b having a substantially right triangle shape, and an emboss 84b corresponding to the emboss 62a of the inlet buffer portion 62 is formed on the pressure loss element 82b. The pressure loss element 82b is set to a size smaller than that of the pressure loss element 82a. The inlet buffer section 62 needs to have an opening cross-sectional area that can maintain the flow rate of the cooling medium supplied to the oxidant gas inlet communication hole 20a side at a desired flow rate. The dimension of the pressure loss element 82b is as follows: Set in response to this request. Therefore, the pressure loss element 82b may not be used.

  Two outlet buffer portions 50 and 66 communicate with the cooling medium outlet communication hole 22b, and the outlet buffer portions 50 and 66 are provided with similar pressure loss generating portions 80c and 80d as necessary. The pressure loss generating portions 80c, 80d include pressure drop elements 82c, 82d having a substantially right triangle shape, and the pressure loss elements 82c, 82d are formed with embosses 84c, 84d corresponding to the embosses 50a, 66a.

  The operation of the fuel cell 10 configured as described above will be described below.

  As shown in FIG. 1, an oxidant gas such as an oxygen-containing gas is supplied to the oxidant gas inlet communication hole 20a, and a fuel gas such as a hydrogen-containing gas is supplied to the fuel gas inlet communication hole 24a. Further, a cooling medium such as pure water or ethylene glycol is supplied to the cooling medium inlet communication hole 22a.

  The oxidant gas is introduced into the oxidant gas channel 32 of the first metal plate 14 from the oxidant gas inlet communication hole 20a. In the oxidant gas flow path 32, the oxidant gas is once introduced into the inlet buffer section 34 and then dispersed in the plurality of oxidant gas flow path grooves 32a. Therefore, the oxidant gas moves along the cathode side electrode 30 of the electrolyte membrane / electrode structure 12 while meandering through the respective oxidant gas flow channel grooves 38.

  On the other hand, the fuel gas is introduced into the fuel gas flow path 52 from the fuel gas inlet communication hole 24 a through the fuel gas inlet hole 58 a of the second metal plate 16. In the fuel gas channel 52, as shown in FIG. 5, the fuel gas is once introduced into the inlet buffer portion 54 and then dispersed into the plurality of fuel gas channel grooves 52a. Further, the fuel gas meanders through each fuel gas flow channel groove 52 a and moves along the anode side electrode 28 of the electrolyte membrane / electrode structure 12.

  Therefore, in the electrolyte membrane / electrode structure 12, the oxidant gas supplied to the cathode side electrode 30 and the fuel gas supplied to the anode side electrode 28 are consumed by an electrochemical reaction in the electrode catalyst layer to generate power. Is done.

  Next, the oxidant gas consumed by being supplied to the cathode side electrode 30 is discharged from the outlet buffer 36 to the oxidant gas outlet communication hole 20b (see FIG. 1). Similarly, the fuel gas supplied to and consumed by the anode side electrode 28 is discharged from the outlet buffer portion 56 to the fuel gas outlet communication hole 24b through the fuel gas outlet hole portion 58b (see FIG. 5).

  On the other hand, the cooling medium supplied to the cooling medium inlet communication hole 22 a is introduced into a cooling medium flow path 42 formed between the first and second metal plates 14 and 16. In the cooling medium flow path 42, as shown in FIG. 7, the cooling medium is temporarily supplied to the inlet buffer sections 44 and 62 via the inlet communication flow paths 43 and 60 extending in the direction of arrow C from the cooling medium inlet communication hole 22a. be introduced.

  The cooling medium introduced into the inlet buffer sections 44 and 62 is dispersed in the plurality of flow path sections 42a and 42b and moves in the horizontal direction (arrow B direction) and the vertical direction (arrow C direction). Therefore, after the cooling medium is supplied over the entire electrode surface of the electrolyte membrane / electrode structure 12, the cooling medium is once introduced into the outlet buffer units 50 and 66, and further through the outlet communication channels 48 and 64. It is discharged to 22b.

  In this case, in the first embodiment, as shown in FIG. 7, among the two inlet buffer portions 44, 62 communicating with the cooling medium inlet communication hole 22a, at least the inlet buffer close to the fuel gas outlet communication hole 24b. In the part 44, the flow of the cooling medium is suppressed via the pressure loss generating part 80a.

  For this reason, the flow rate of the cooling medium supplied to the cooling medium flow path 42 from the cooling medium inlet communication hole 22a via the inlet buffer 44 is reduced. At that time, in the fuel gas flow path 52 and the oxidant gas flow path 32, the power generation capacity on the downstream side is likely to decrease, and condensed water may be generated.

  Therefore, the flow rate of the cooling medium is reduced corresponding to the downstream side of the fuel gas passage 52 and the oxidant gas passage 32, so that the downstream temperature rises and the fuel gas and the oxidant gas are warmed. Thus, the condensed water in the fuel gas channel 52 and the oxidant gas channel 32 is steamed and taken into the fuel gas and the oxidant gas. Thereby, it is possible to prevent the condensed water from staying in the fuel gas flow path 52 and the oxidant gas flow path 32, and to obtain an effect that a good waste water treatment can be reliably performed.

  On the other hand, the other inlet buffer 62 is close to the oxidant gas inlet communication hole 20a, and the flow rate of the coolant supplied to the coolant flow path 42 corresponding to the inlet side of the oxidant gas flow path 32 is small. To increase. Therefore, in the oxidant gas flow channel 32 and the fuel gas flow channel 52, the amount of the cooling medium is increased on the upstream side where the reaction tends to concentrate, and the upstream side can be effectively cooled. For this reason, it is possible to prevent the electrolyte membrane / electrode structure 12 from reaching a high temperature and perform stable power generation.

  The inlet buffer 62 and the outlet buffers 50 and 66 are provided with pressure loss generators 80b to 80d as necessary. As a result, the flow rate of the cooling medium in the cooling medium flow path 42 is adjusted well, and the current density distribution over the entire power generation surface can be made uniform.

  Moreover, the pressure loss elements 82a to 82d constituting the pressure loss generating portions 80a to 80d are detachable from the embosses 44a, 62a, 50a, and 66a, respectively. Therefore, it is possible to apply to various fuel cells 10 only by setting the dimensions of the pressure loss elements 82a to 82d, and there is an advantage that the versatility is excellent.

  FIG. 8 is a schematic perspective view of a fuel cell stack 100 according to the second embodiment of the present invention.

  The fuel cell stack 100 includes a first stacked body 102a in which a predetermined number of fuel cells 10 are stacked on the center side in the stacking direction, and a predetermined number of fuel cells 10 are similarly provided on both sides of the first stacked body 102a. The stacked second stacked body 102b is stacked. Further, a third stacked body 102c in which a predetermined number of fuel cells 10 are stacked is stacked on both sides of the second stacked body 102b.

  Terminal plates 104a and 104b, insulator plates 106a and 106b, and end plates 108a and 108b are stacked on the third stacked body 102c at both ends in the stacking direction, and these are integrally clamped and held by a tie rod (not shown).

  The fuel cell 10 disposed in the first stacked body 102a generates pressure loss in the inlet buffer portion (see the inlet buffer portion 44 in FIG. 7) that communicates with the cooling medium inlet communication hole 22a and is close to the fuel gas outlet communication hole 24b. A portion 110a is provided. Similarly, each fuel cell 10 constituting the second and third stacked bodies 102b and 102c is provided with pressure loss generating portions 110b and 110c in an inlet buffer portion (not shown).

  Each of the pressure loss generating portions 110a to 110c includes pressure loss elements 112a to 112c that are detachable and have different sizes. While the pressure loss element 112a is set to the minimum dimension, the pressure loss element 112c is set to the maximum dimension, and the pressure loss elements 112a to 112c are provided with embosses 114a to 114c.

  In the fuel cell stack 100 configured as described above, the first to third stacked bodies 102a to 102c are provided with pressure loss elements 112a to 112c having different sizes, respectively, and as shown in FIG. The cooling medium flow rate in the third stacked bodies 102a to 102c is changed.

  For this reason, in particular, in the third stacked body 102c provided at the end of the fuel cell stack 100 in the stacking direction, the temperature tends to become low due to heat dissipation, but the flow rate of the cooling medium supplied to the third stacked body 102c is The flow rate of the cooling medium supplied to the first stacked body 102a and the second stacked body 102b on both sides of the first stacked body 102a can be set smaller.

  As a result, the fuel cell 10 constituting the third stacked body 102c can prevent an increase in concentration overvoltage or a decrease in catalyst activity due to condensation, and the fuel cell stack 100 as a whole can efficiently generate power. The effect is obtained. In addition, in the first to third stacked bodies 102a to 102c, the same fuel cell 10 can be used, and the advantages of being versatile and economical are obtained.

  In addition, as shown in FIG. 7, in the other inlet buffer parts 62 and the outlet buffer parts 50 and 66, pressure loss elements (not shown) having different sizes with respect to the first to third stacked bodies 102a to 102c are similarly shown. The cooling medium supply flow rate in the stacking direction of the fuel cell stack 100 may be adjusted.

  Further, in the first and second embodiments, the coolant flow path 42 is integrated with the oxidant gas flow path 32 of the serpentine flow path and the back side of the fuel gas flow path 52 that are reciprocated halfway in the direction of arrow B, respectively. However, the present invention is not limited to this. For example, the oxidant gas channel 32 and the fuel gas channel 52 may be substantially U-shaped channels.

It is a principal part disassembled perspective view of the fuel cell which concerns on the 1st Embodiment of this invention. FIG. 3 is a partial cross-sectional explanatory view of a fuel cell stack in which the fuel cells are stacked. It is explanatory drawing of one surface of a 1st metal plate. It is explanatory drawing of the other surface of the said 1st metal plate. It is explanatory drawing of one surface of a 2nd metal plate. It is explanatory drawing of the other surface of the said 2nd metal plate. It is a perspective explanatory view of a cooling medium channel formed in a metal separator. 6 is a schematic perspective view of a fuel cell stack according to a second embodiment of the present invention. FIG. It is explanatory drawing of the supply amount of the cooling medium with respect to the lamination direction of the said fuel cell stack.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Fuel cell 11, 100 ... Fuel cell stack 12 ... Electrolyte membrane and electrode structure 13 ... Separator 14, 16 ... Metal plate 14a, 14b, 16a, 16b ... Surface 20a ... Oxidant gas inlet communication hole 20b ... Oxidant gas Outlet communication hole 22a ... Cooling medium inlet communication hole 22b ... Cooling medium outlet communication hole 24a ... Fuel gas inlet communication hole 24b ... Fuel gas outlet communication hole 26 ... Solid polymer electrolyte membrane 28 ... Anode side electrode 30 ... Cathode side electrode 32 ... Oxidant gas flow path 34, 44, 54, 62 ... Inlet buffer part 34a, 36a, 44a, 50a, 54a, 56a, 62a, 66a, 84a-84d, 114a-114c ... Emboss 36, 50, 56, 66 ... Outlet Buffer unit 42 ... cooling medium channel 52 ... fuel gas channels 80a to 80d, 110a to 110c ... pressure loss generating unit 82a 82d, 112a~112c ... pressure loss element 102a~102c ... laminate

Claims (5)

An electrolyte / electrode structure having an electrolyte sandwiched between a pair of electrodes, the electrolyte / electrode structure sandwiched between first and second separators, and penetrating in the stacking direction to communicate with a reaction gas inlet and a reaction gas outlet A cooling medium communicating with the cooling medium inlet communication hole and the cooling medium outlet communication hole is formed between the first and second separators, which are formed with a hole, a cooling medium inlet communication hole, and a cooling medium outlet communication hole. A fuel cell in which a medium flow path is formed,
The cooling medium flow path communicates with the cooling medium inlet communication hole via at least two inlet buffer portions, and
The fuel cell according to claim 1, wherein a pressure loss generation portion that suppresses the flow of the cooling medium is provided at least in the inlet buffer portion adjacent to the reaction gas outlet communication hole among the two inlet buffer portions. The fuel cell according to claim 1, wherein the inlet buffer portion has an embossing.
The fuel cell according to claim 1, wherein the pressure loss generator includes a pressure loss element that is detachable from the emboss.   3. The fuel cell according to claim 2, wherein the pressure loss generating portion includes at least two types of pressure loss elements having different sizes, and the size of the pressure loss element is selected in accordance with the inlet buffer portion. battery. An electrolyte / electrode structure having an electrolyte sandwiched between a pair of electrodes, the electrolyte / electrode structure sandwiched between first and second separators, and penetrating in the stacking direction to communicate with a reaction gas inlet and a reaction gas outlet A cooling medium communicating with the cooling medium inlet communication hole and the cooling medium outlet communication hole is formed between the first and second separators, which are formed with a hole, a cooling medium inlet communication hole, and a cooling medium outlet communication hole. A fuel cell stack comprising a fuel cell in which a medium flow path is formed and laminating a plurality of the fuel cells,
The cooling medium flow path communicates with the cooling medium inlet communication hole via at least two inlet buffer portions, and
Among the two inlet buffer portions, at least the inlet buffer portion close to the reaction gas outlet communication hole is provided with a pressure loss generating portion that suppresses the flow of the cooling medium,
The fuel cell stack characterized in that the pressure loss generation part of the fuel cell on the end side in the stacking direction is set to a size larger than the pressure loss generation part of the fuel cell on the center side in the stacking direction. 5. The fuel cell stack according to claim 4, wherein the inlet buffer portion has embossing,
The fuel cell stack, wherein the pressure loss generating portion includes at least two different types of pressure loss elements that are detachably attached to the emboss.

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