JP2011159473A - Fuel cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel cell having a compact constitution in which a fuel flow pattern is optimized to achieve high fuel utilization rate. <P>SOLUTION: In the fuel cell, a fuel cell stack 1 formed by arranging unit cells in a plurality of rows along the axial direction is structured as an N-stage constitution composed of N-pieces of stacks to install an isolating plate 6 between the stacks, and on both side faces of the fuel cell stack 1, fuel gas manifolds 7, 8 are installed which are equipped with gas chambers in order to supply fuel gas to a fuel gas flow passage of each unit cell of the fuel cell stack 1. The fuel gas manifolds 7, 8 are equipped with a plurality of spaces formed by being partitioned bordering at least between the stacks. A communication flow passage between the stacks to communicate a first space opposed to a fuel outlet of the i-th (i is an integer of 1 or more and N-1 or less) stack with a second space opposed to the fuel inlet of (i+1)-th stack is installed at least at one of the fuel gas manifolds 7, 8. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an external manifold type fuel cell in which one stack is divided into an upstream stack and a downstream stack by a separator.

  A fuel cell is a power generator that supplies fuel such as hydrogen and an oxidant such as air to the fuel cell body and reacts them electrochemically, thereby converting the chemical energy of the fuel directly into electrical energy and taking it out. It is.

  Applications of fuel cells include industrial use for factories and hospitals, general household use, and automobile use. From the viewpoint of recent global warming issues, effective use of resources, and differentiation from existing power generation facilities. Fuel cells are required to have high power generation efficiency.

  Patent Documents 1 and 2 disclose techniques for improving power generation efficiency and the like in a fuel cell including a plurality of stacks.

Japanese Patent Publication No. 8-24055 JP 2001-196087 A

  The fuel cell of Patent Document 1 attempts to increase power generation efficiency while maintaining safety, but piping is required between the first stack and the second stack, and there is a problem that the battery becomes large. There is a risk that moisture will condense in the piping and disturb the gas flow, or the condensed water may flow locally to the cell with the second stack and adversely affect the reaction gas distribution in the second stack.

  On the other hand, in the fuel cell of Patent Document 2, compared to Patent Document 1, a compact configuration is realized by installing a partition plate, but optimization of the fuel flow pattern as a whole fuel cell stack can be realized. It ’s hard to say.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a fuel cell and a fuel cell system capable of optimizing a fuel flow pattern and realizing a high fuel utilization rate with a compact configuration.

  In a fuel cell according to an aspect of the present invention, a fuel cell stack in which unit cells are arranged in a plurality of rows along the axial direction has an N-stage configuration including N stacks, and a separator is provided between the stacks. In the fuel cell in which first and second fuel gas manifolds having gas chambers for supplying fuel gas to the fuel gas flow path of each unit cell of the fuel cell stack are provided on both side surfaces of the battery stack, The first and second fuel gas manifolds include a plurality of spaces partitioned at least between the stacks, and face the fuel outlet of the i-th stack (i is an integer not less than 1 and not more than N-1). An inter-stack communication flow path that connects the first space and the second space facing the fuel inlet of the (i + 1) th stack is provided in at least one of the first and second fuel gas manifolds. And wherein the are.

  A fuel cell according to another aspect of the present invention has a fuel cell stack in which unit cells are arranged in a plurality of rows along the axial direction, and has an N-stage configuration including N stacks, and a separator is provided between the stacks. A fuel cell in which first and second fuel gas manifolds having gas chambers for supplying fuel gas to fuel gas passages of each unit cell of the fuel cell stack are provided on both side surfaces of the fuel cell stack. The first and second fuel gas manifolds have at least a plurality of spaces partitioned between the stacks, and face the fuel outlet of the i-th stack (i is an integer not less than 1 and not more than N-1). The inter-stack communication flow path that connects the first space and the second space facing the fuel inlet of the (i + 1) th stack is provided in the separator.

  ADVANTAGE OF THE INVENTION According to this invention, a fuel cell and a fuel cell system which can optimize a fuel flow pattern with a compact structure and can implement | achieve a high fuel utilization rate can be provided.

FIG. 1 is a perspective view showing an appearance of a fuel cell according to the first embodiment of the present invention. FIG. 2 is a graph for explaining the utilization rate of the fuel gas. FIG. 3A is a conceptual diagram showing the flow of fuel gas inside the first stack 2 provided in the fuel cell of FIG. 1 when viewed horizontally from the direction perpendicular to the longitudinal direction. (B) is a conceptual diagram showing the flow of the fuel gas inside when the second stack 3 provided in the fuel cell of FIG. 1 is viewed horizontally from the direction perpendicular to the longitudinal direction. 4A is a diagram showing a shape of the fuel inlet / outlet manifold 7 provided in the fuel cell of FIG. 1 when viewed horizontally from each stack side, and FIG. 4B is a diagram of FIG. It is a figure which shows the shape at the time of seeing horizontally the fuel return manifold 8 with which a fuel cell is equipped from each stack side. FIG. 5 is a diagram showing the shape of the fuel inlet / outlet manifold 7 and the inter-stack communication channel 11 provided in the fuel cell of FIG. 1 when viewed horizontally from the outside in the longitudinal direction of each stack. FIG. 6 is a cross-sectional view showing a detailed cross-sectional shape of the fuel inlet / outlet manifold 7 and the inter-stack communication channel 11 at the AA portion in FIG. FIG. 7 is a perspective view showing an appearance of a fuel cell according to the second embodiment of the present invention. FIG. 8A is a conceptual diagram showing the flow of the fuel gas inside when the first stack 32 provided in the fuel cell of FIG. 7 is viewed horizontally from the direction perpendicular to the longitudinal direction. FIG. 8B is a conceptual diagram showing the flow of fuel gas inside when the second stack 33 provided in the fuel cell of FIG. 7 is viewed horizontally from a direction perpendicular to the longitudinal direction thereof. FIG. 9A is a diagram showing a shape of the fuel inlet / outlet manifold 37 provided in the fuel cell of FIG. 7 when viewed horizontally from each stack side, and FIG. 9B is a diagram of FIG. It is a figure which shows the shape at the time of seeing horizontally the fuel return manifold 38 with which a fuel cell is equipped from each stack side. FIG. 10 is a perspective view showing an appearance of a fuel cell according to the third embodiment of the present invention. FIG. 11 is a plan view showing the structure of the separator 56 provided in the fuel cell of FIG. 10 and the fuel gas flow. 12 (a) is a conceptual diagram showing the flow of fuel gas inside the first stack 52 provided in the fuel cell of FIG. 10 when viewed horizontally from the direction perpendicular to the longitudinal direction. (B) is a conceptual diagram showing the flow of the fuel gas inside when the second stack 53 provided in the fuel cell of FIG. 10 is viewed horizontally from the direction perpendicular to the longitudinal direction thereof. FIG. 13A is a view showing the shape of the fuel inlet / return manifold 57 provided in the fuel cell of FIG. 10 when viewed horizontally from each stack side, and FIG. 13B is a view of FIG. It is a figure which shows the shape at the time of seeing horizontally the fuel return / outlet manifold 58 with which a fuel cell is provided from each stack side. FIG. 14 is a perspective view showing an appearance of a fuel cell according to the fourth embodiment of the present invention. 15 is a plan view showing the structure of the separator plate 76 provided in the fuel cell of FIG. 14 and the fuel gas flow. 16 (a) is a conceptual diagram showing the flow of fuel gas inside the first stack 72 provided in the fuel cell of FIG. 14 when viewed horizontally from the direction perpendicular to the longitudinal direction. (B) is a conceptual diagram showing the flow of the fuel gas inside when the second stack 73 provided in the fuel cell of FIG. 14 is viewed horizontally from the direction perpendicular to the longitudinal direction. FIG. 17A is a view showing a shape of the fuel inlet / return manifold 77 provided in the fuel cell of FIG. 14 when viewed horizontally from each stack side, and FIG. 17B is a view of FIG. It is a figure which shows the shape at the time of seeing horizontally the fuel return / outlet manifold 78 with which a fuel cell is provided from each stack side. FIG. 18 is a perspective view showing an appearance of a fuel cell system according to the fifth embodiment of the present invention. FIG. 19 is a perspective view showing an appearance of a fuel cell system according to the sixth embodiment of the present invention.

  Embodiments of the present invention will be described below with reference to the drawings.

(First embodiment)
First, a first embodiment of the present invention will be described with reference to FIGS.

  FIG. 1 is a perspective view showing an appearance of a fuel cell according to the first embodiment of the present invention.

  The fuel cell shown in FIG. 1 has a fuel electrode disposed on one side with an electrolyte in between, an oxidant electrode disposed on the other side, and a fuel gas flow path outside the fuel electrode of each electrode. And a fuel cell stack 1 in which unit cells in which separators having an oxidant gas flow path are arranged outside the oxidant electrode are arranged in a plurality of rows along the axial direction. A two-stage configuration consisting of two stacks 3, a current collector plate 4 is provided outside the first stack 2, a current collector plate 5 is provided outside the second stack 3, and a separator 6 is provided between the stacks, A fuel inlet / outlet manifold 7 is provided on the fuel inlet / outlet side of the fuel cell stack 1 as a fuel gas manifold having a gas chamber for supplying fuel gas to the fuel gas flow path of each unit cell of the fuel cell stack 1. On the fuel return side Fee return manifold 8 is provided, a fuel inlet pipe 9 and the fuel outlet pipe 10 provided in the fuel inlet / outlet manifold 7, further comprising a structure in which a stack between communication passage 11 to the outside of the fuel inlet / outlet manifold 7. The inter-stack communication channel 11 guides the fuel gas from the low space in the fuel inlet / outlet manifold 7 to the high space in the same fuel inlet / outlet manifold 7. Note that the number of unit cells is smaller in the second stack 3 than in the first stack 2 (for example, a ratio of 65% to 35%).

  Further, in order to function as a fuel cell, an oxidant manifold and a coolant manifold are also necessary. However, these are not directly related to the present invention, so in this embodiment, an oxidant manifold and a coolant manifold are illustrated. Is omitted (the same applies to other embodiments).

  By the way, as one of the methods for increasing the efficiency, there is a method of improving the fuel utilization rate (ratio of consumption to the amount of fuel supply). In the case of a plant equipped with a reformer that converts fuel into hydrogen, the fuel gas discharged from the fuel cell is used as a heat source, but in the case of a pure hydrogen fuel plant, hydrogen that is not used for power generation is exhausted. Therefore, it is indispensable for improving the plant efficiency to improve the fuel utilization rate.

  In a fuel cell having a two-stage fuel cell stack composed of two stacks as in this embodiment, 65% of the number of single cells in the entire fuel cell is the first stack, and the remaining 35% of single cells Is the second stack, as shown in FIG. 2, the utilization rate of each stack can be made lower than the overall utilization rate in all areas. For example, if the overall fuel gas utilization ratio is 70%, the actual utilization ratio of the fuel gas in the first stack is 70% × 0.65 = 45.5%, and the fuel gas in the second stack The actual utilization ratio of the stack is 0.35 / {(100% / 70%) − 0.65} × 100 = 45.0%, and the utilization ratio of the individual stacks without changing the overall utilization ratio of the fuel gas It is possible to increase the flow rate of the fuel gas supplied to the individual stacks without decreasing the flow rate, that is, without changing the overall flow rate of the fuel gas. Such a method is effective in improving the plant efficiency because the entire fuel gas flow rate can be reduced. Therefore, in this embodiment, such a method is applied to the first stack 2 and the second stack 3 described above (the same applies to other embodiments).

  FIG. 3A is a conceptual diagram showing the flow of fuel gas inside the first stack 2 provided in the fuel cell of FIG. 1 when viewed horizontally from the direction perpendicular to the longitudinal direction. (B) is a conceptual diagram showing the flow of the fuel gas inside when the second stack 3 provided in the fuel cell of FIG. 1 is viewed horizontally from the direction perpendicular to the longitudinal direction. 4A is a view showing the shape of the fuel inlet / outlet manifold 7 provided in the fuel cell of FIG. 1 when viewed horizontally from each stack side, and FIG. It is a figure which shows the shape at the time of seeing horizontally the fuel return manifold 8 with which one fuel cell is provided from each stack side.

  As shown in FIG. 3A, the first stack 2 has a first path 2A and a second path 2B as paths through which the fuel gas flows. In addition, as shown in FIG. 3B, the second stack 3 has a first path 3A and a second path 3B as paths through which the fuel gas flows. As can be seen from FIGS. 3A and 3B, the first stack 2 and the second stack 3 have a common two-stage path configuration. Details of the fuel gas flow will be described later.

  As shown in FIG. 4A, the fuel inlet / outlet manifold 7 is divided into four spaces 7A, 7B, and 7C, which are partitioned between the stacks and between the fuel gas paths. , 7D. A fuel inlet pipe 9 is connected to the space 7A, a fuel outlet pipe 10 is connected to the space 7D, and both the spaces 7B and 7C are connected to both via the openings 12 and 13 provided in the fuel inlet / outlet manifold 7. The inter-stack communication flow path 11 that connects the space outside the fuel inlet / outlet manifold 7 is connected. The space 7A is opposed to the first path 2A of the first stack 2, the space 7B is opposed to the second path 2B of the first stack 2, and the space 7C is the first of the second stack 3. The space 7 </ b> D faces the second path 3 </ b> B of the second stack 3.

  On the other hand, as shown in FIG. 4 (b), the fuel return manifold 8 has two spaces 8A and 8B that are partitioned between the stacks. The space 8A faces the first path 2A and the second path 2B of the first stack 2, and the space 8B faces the first path 3A and the second path 3B of the second stack 3. Yes.

  FIG. 5 is a diagram showing the shape of the fuel inlet / outlet manifold 7 and the inter-stack communication channel 11 provided in the fuel cell of FIG. 1 when viewed horizontally from the outside in the longitudinal direction of each stack. FIG. 6 is a cross-sectional view showing a detailed cross-sectional shape of the fuel inlet / outlet manifold 7 and the inter-stack communication flow path 11 at the section AA in FIG.

  As shown in FIGS. 5 and 6, in the inter-stack communication flow path 11, the space 14 that connects the first opening 12 and the second opening 13 is sealed outside the fuel inlet / outlet manifold 7. As described above, the connecting flow path lid 11a is attached to the outside of the fuel inlet / outlet manifold 7. Specifically, in order to form a space 14 between the communication flow path lid 11 a and the fuel inlet / outlet manifold 7, lid attaching portions 15 and 16 constituting a part of the fuel inlet / outlet manifold 7. The communication channel lid 11a is processed with an O-ring groove, and the communication channel lid O-rings 17 and 18 in contact with the lid mounting portions 15 and 16 are provided in the groove. The connecting channel lid 11a is fixed to the fuel inlet / outlet manifold 7 by connecting channel lid fastening portions 19 and 20 including bolts, screws and nuts.

  Here, with reference to FIG. 3 and FIG. 4, the fuel gas flow in this embodiment is demonstrated. During operation of the fuel cell system, fuel gas, oxidant gas, and cooling water are respectively supplied to the fuel cell stack 1, but only the flow of the fuel gas is shown here.

  When the fuel gas is supplied to the space 7 A of the fuel inlet / outlet manifold 7 through the fuel inlet pipe 9, the fuel gas passes through the first path 2 A of the first stack 2 and turns back in the space 8 A of the fuel return manifold 8. , Through the second path 2B of the first stack 2 and into the space 7B of the fuel inlet / outlet manifold 7. The fuel gas that has entered the space 7B passes through the inter-stack communication channel 11 via the opening 12 of the fuel inlet / outlet manifold 7, and enters the space 7C via the opening 13 of the fuel inlet / outlet manifold 7. The fuel gas that has entered the space 7C passes through the first path 3A of the second stack 3, turns back in the space 8B of the fuel return manifold 8, passes through the second path 3B of the second stack 3, and enters the fuel inlet / It enters the space 7D of the outlet manifold 7. The fuel gas that has entered the space 7D, that is, the fuel gas that has not been consumed in the fuel cell stack 1, is discharged from the fuel outlet pipe 10.

  In the present embodiment, the fuel cell stack 1 is illustrated as having a two-stage configuration including the first stack 2 and the second stack 3, but is not limited to this, and includes three or more stacks. It is good also as a structure of 3 steps | paragraphs or more. When the fuel cell stack 1 has an N-stage configuration including N stacks, the space facing the fuel outlet of the i-th stack (i is an integer not less than 1 and not more than N-1) and the fuel in the i + 1-th stack An inter-stack communication flow path 11 that communicates with a space facing the inlet is provided outside the fuel inlet / outlet manifold 7.

  According to the first embodiment, the first stack 2 and the second stack 3 of the fuel cell stack 1 can be regarded as the same stack, and between the stacks outside the fuel inlet / outlet manifold 7. Since the communication channel 11 is provided, there is no need to provide a fuel gas pipe, an oxidant gas pipe, and a cooling water pipe between the first stack 2 and the second stack 3, and the compact fuel cell stack 1 can be formed. Can be realized.

  In addition, since the inter-stack communication channel 11 is provided outside the fuel inlet / outlet manifold 7, the fuel cell stack 1 is maintained while maintaining a high fuel utilization rate without being restricted by the structural constraints of the fuel cell stack 1. The overall fuel flow pattern can be optimized.

  In addition, since the inter-stack communication flow path 11 between the first stack 2 and the second stack 3 is short, heat radiation between the first stack 2 and the second stack 3 is small, and moisture is contained in the gas pipe. Can be prevented from condensing and disturbing the gas flow, or the condensed water locally flowing to a cell in the second stack 3 and adversely affecting the reaction gas distribution in the second stack 3.

  Further, in each of the first stack 2 and the second stack 3, a flow pattern in which the fuel gas flows from the top to the bottom can be formed, so that moisture condensed in the fuel gas flow path and each manifold can be smoothly discharged to the outside. Can be discharged.

(Second Embodiment)
Next, a second embodiment of the present invention will be described with reference to FIGS.

  FIG. 7 is a perspective view showing an appearance of a fuel cell according to the second embodiment of the present invention.

  The fuel cell shown in FIG. 7 is a separator in which a fuel electrode is arranged on one side with an electrolyte in between, an oxidant electrode is arranged on the other side, and a fuel gas channel is provided outside the fuel electrode of each electrode. A fuel cell stack 31 in which unit cells in which separators having an oxidant gas flow path are arranged outside the oxidant electrode are arranged in a plurality of rows along the axial direction are provided as a first stack 32 and a first stack. A two-stage configuration comprising two stacks 33, a current collector plate 34 provided outside the first stack 32, a current collector plate 35 provided outside the second stack 33, and a separator plate 36 provided between the stacks, As a fuel gas manifold having a gas chamber for supplying fuel gas to the fuel gas flow path of each unit cell of the fuel cell stack 31, a fuel inlet / outlet manifold 37 is provided on the fuel inlet / outlet side of the fuel cell stack 31. The fuel return manifold 38 is provided on the fuel return side, the fuel inlet pipe 39 and the fuel outlet pipe 40 are provided on the fuel inlet / outlet manifold 37, and the inter-stack communication channel 41 is provided outside the fuel return manifold 38. It has a configuration. The inter-stack communication channel 41 guides the fuel gas from a low space in the fuel return manifold 38 to a high space in the same fuel return manifold 38. It is assumed that the number of unit cells is smaller in the second stack 33 than in the first stack 32 (for example, a ratio of 65% to 35%).

  FIG. 8A is a conceptual diagram showing the flow of the fuel gas inside when the first stack 32 provided in the fuel cell of FIG. 7 is viewed horizontally from the direction perpendicular to the longitudinal direction. FIG. 8B is a conceptual diagram showing the flow of fuel gas inside when the second stack 33 provided in the fuel cell of FIG. 7 is viewed horizontally from a direction perpendicular to the longitudinal direction thereof. 9A is a diagram showing the shape of the fuel inlet / outlet manifold 37 provided in the fuel cell of FIG. 7 when viewed horizontally from each stack side, and FIG. 7 is a view showing a shape when a fuel return manifold 38 provided in the fuel cell 7 is viewed horizontally from each stack side. FIG.

  As shown in FIG. 8A, the first stack 32 has a first path 32A, a second path 32B, and a third path 32C as paths through which the fuel gas flows. Further, as shown in FIG. 8B, the second stack 33 has a first path 33A, a second path 33B, and a third path 33C as paths through which the fuel gas flows. As can be seen from FIGS. 8A and 8B, the first stack 32 and the second stack 33 have a common three-stage path configuration. Details of the fuel gas flow will be described later.

  As shown in FIG. 9 (a), the fuel inlet / outlet manifold 33 is divided into four spaces 37A, which are partitioned between the stacks and between some paths of the fuel gas. 37B, 37C, 37D. A fuel inlet pipe 39 is connected to the space 37A, and a fuel outlet pipe 40 is connected to the space 37D. The space 37A is opposed to the first path 32A of the first stack 32, the space 37B is opposed to the second path 32B and the third path 32C of the first stack 32, and the space 37C is the second path The first path 33A and the second path 33B of the stack 33 are opposed to each other, and the space 37D is opposed to the third path 33C of the second stack 33.

  On the other hand, as shown in FIG. 9B, the fuel return manifold 38 has four spaces 38A, 38B, 38C, and 38D that are partitioned between the stacks. The aforementioned inter-stack communication flow path 41 that connects both spaces outside the fuel return manifold 38 is connected to the spaces 38B and 38C through the openings 12 and 13 provided in the fuel return manifold 38. The space 38A is opposed to the first path 32A and the second path 32B of the first stack 32, the space 38B is opposed to the third path 32C of the first stack 32, and the space 38C is the second path 32C. The space 38 </ b> D faces the second path 33 </ b> B and the third path 33 </ b> C of the second stack 33.

  The shape when the fuel return manifold 38 and the inter-stack communication channel 41 provided in the fuel cell of FIG. 7 are viewed horizontally from the outside in the longitudinal direction of each stack and the detailed cross-sectional shape thereof are described above. Since it becomes the same as that of what was shown in Drawing 5 and Drawing 6 in a 1st embodiment, those illustration and explanation are omitted here.

  Here, with reference to FIG. 8 and FIG. 9, the fuel gas flow in this embodiment is demonstrated. During operation of the fuel cell system, fuel gas, oxidant gas, and cooling water are respectively supplied to the fuel cell stack 31, but only the flow of the fuel gas is shown here.

  When the fuel gas is supplied to the space 37 A of the fuel inlet / outlet manifold 37 through the fuel inlet pipe 39, the fuel gas passes through the first path 32 A of the first stack 32 and turns back in the space 38 A of the fuel return manifold 38. , Through the second path 32B of the first stack 32, and further folded back in the space 37B of the fuel inlet / outlet manifold 37, through the third path 32C of the first stack 32, and into the space 38B of the fuel return manifold 38. enter. The fuel gas that has entered the space 38 </ b> B passes through the inter-stack communication channel 41 through the opening 42 of the fuel return manifold 38 and enters the space 38 </ b> C through the opening 43 of the fuel return manifold 38. The fuel gas that has entered the space 38C passes through the first path 33A of the second stack 33, turns back in the space 37C of the fuel inlet / outlet manifold 37, passes through the second path 33B of the second stack 33, and flows into the fuel. It further turns back in the space 38D of the return manifold 38, passes through the third path 33C of the second stack 33, and enters the space 37D of the fuel inlet / outlet manifold 37. The fuel gas that has entered the space 37D, that is, the fuel gas that has not been consumed in the fuel cell stack 31, is discharged from the fuel outlet pipe 40.

  In the present embodiment, the fuel cell stack 31 is illustrated as having a two-stage configuration including the first stack 32 and the second stack 33. However, the present invention is not limited to this and includes three or more stacks. It is good also as a structure of 3 steps | paragraphs or more. When the fuel cell stack 31 has an N-stage configuration composed of N stacks, the space facing the fuel outlet of the i-th stack (i is an integer not less than 1 and not more than N-1) and the fuel in the i + 1-th stack An inter-stack communication flow path 41 that communicates with the space facing the inlet is provided outside the fuel return manifold 38.

  According to the second embodiment, even when another flow pattern different from the first embodiment is applied, the same effect as that of the first embodiment can be obtained.

(Third embodiment)
Next, a third embodiment of the present invention will be described with reference to FIGS.

  FIG. 10 is a perspective view showing an appearance of a fuel cell according to the third embodiment of the present invention.

  The fuel cell shown in FIG. 10 has a fuel electrode disposed on one side with an electrolyte in between, an oxidant electrode disposed on the other side, and a fuel gas channel provided outside the fuel electrode of each electrode. And a fuel cell stack 51 in which unit cells in which separators having an oxidant gas flow path are arranged outside the oxidant electrode are arranged in a plurality of rows along the axial direction. Two stacks 53, a current collector 54 is provided outside the first stack 52, a current collector 55 is provided outside the second stack 53, and a separator 56 is provided between the stacks. As a fuel gas manifold having a gas chamber for supplying fuel gas to the fuel gas flow path of each unit cell of the fuel cell stack 51, a fuel inlet / return manifold 57 is provided on the fuel inlet side of the fuel cell stack 51. Therefore, a fuel return / outlet manifold 58 is provided on the fuel outlet side, a fuel inlet pipe 59 is provided in the fuel inlet / return manifold 57, a fuel outlet pipe 60 is provided in the fuel return / outlet manifold 58, and In this configuration, the inter-stack communication channel is provided. The separator 56 according to the present embodiment is provided with a slightly wider width than the separators according to the first and second embodiments described above because the inter-stack communication channel needs to be provided therein. To do. Note that the number of unit cells is smaller in the second stack 3 than in the first stack 2 (for example, a ratio of 65% to 35%).

  FIG. 11 is a plan view showing the structure of the separator 56 provided in the fuel cell of FIG. 10 and the fuel gas flow.

  As shown in FIG. 11, the separator plate 56 has an inter-stack communication channel 61 therein. The inter-stack communication channel 61 is formed along the surface of the separator 56 from the opening 62 in the lower portion of the edge on the fuel return / outlet manifold 58 side to the opening in the upper portion of the edge on the fuel inlet / return manifold 57 side. This is realized by a through hole penetrating to 63. The inter-stack communication channel 61 guides fuel gas from a low space in the fuel inlet / return manifold 57 to a high space in the fuel return / outlet manifold 58.

  12 (a) is a conceptual diagram showing the flow of fuel gas inside the first stack 52 provided in the fuel cell of FIG. 10 when viewed horizontally from the direction perpendicular to the longitudinal direction. (B) is a conceptual diagram showing the flow of the fuel gas inside when the second stack 53 provided in the fuel cell of FIG. 10 is viewed horizontally from the direction perpendicular to the longitudinal direction thereof. FIG. 13A is a diagram showing the shape of the fuel inlet / return manifold 57 provided in the fuel cell of FIG. 10 when viewed horizontally from each stack side, and FIG. FIG. 10 is a diagram showing a shape of a fuel return / outlet manifold 58 provided in 10 fuel cells when viewed horizontally from each stack side.

  As shown in FIG. 12A, the first stack 52 has a first path 52A and a second path 52B as paths through which the fuel gas flows. Further, as shown in FIG. 12B, the second stack 53 includes a first path 53A and a second path 53B as paths through which the fuel gas flows. As can be seen from FIGS. 12A and 12B, the first stack 52 and the second stack 53 have a common two-stage path configuration. Details of the fuel gas flow will be described later.

  As shown in FIG. 13A, the fuel inlet / return manifold 57 is divided into three spaces 57A, which are partitioned between the stacks and part of the paths of the fuel gas. 57B, 57C. A fuel inlet pipe 59 is connected to the space 57A, and the inter-stack communication flow communicates with the space 58B of the fuel return / outlet manifold 58 through the openings 62 and 63 provided in the separator 56 in the space 57B. A path 61 is connected. The space 57A is opposed to the first path 52A of the first stack 52, the space 57B is opposed to the second path 52B of the first stack 52, and the space 57C is the first of the second stack 53. Opposite to the second path 53A and the second path 53B.

  On the other hand, as shown in FIG. 13 (b), the fuel return / outlet manifold 58 is divided into three spaces, which are partitioned between the stacks and between some paths of the fuel gas. 58A, 58B, 58C. The fuel outlet pipe 60 is connected to the space 58C, and the inter-stack communication flow that communicates with the space 57B of the fuel inlet / return manifold 57 via the openings 63 and 62 provided in the separator 56 is connected to the space 58B. A path 61 is connected. The space 58A is opposed to the first path 52A and the second path 52B of the first stack 52, the space 57B is opposed to the first path 53A of the second stack 53, and the space 57C is the second path This is opposed to the second path 53B of the stack 53.

  Here, with reference to FIG. 11 thru | or FIG. 13, the fuel gas flow in this embodiment is demonstrated. During operation of the fuel cell system, fuel gas, oxidant gas, and cooling water are respectively supplied to the fuel cell stack 51, but only the flow of the fuel gas is shown here.

  When the fuel gas is supplied to the space 57A of the fuel inlet / return manifold 57 through the fuel inlet pipe 59, the fuel gas passes through the first path 52A of the first stack 52 and the space 58A of the fuel return / outlet manifold 58. And passes through the second path 52B of the first stack 52 and enters the space 57B of the fuel inlet / return manifold 57. The fuel gas that has entered the space 57B passes through the inter-stack communication channel 61 through the opening 62 of the separator 56 and enters the space 58B of the fuel return / outlet manifold 58 through the opening 63 of the separator 56. The fuel gas that has entered the space 58B passes through the first path 53A of the second stack 53, turns back in the space 57C of the fuel inlet / return manifold 57, passes through the second path 53B of the second stack 53, and passes through the fuel. Enter space 58C of return / outlet manifold 58. The fuel gas that has entered the space 58 </ b> C, that is, the fuel gas that has not been consumed in the fuel cell stack 51 is discharged from the fuel outlet pipe 60.

  In the present embodiment, the fuel cell stack 51 is illustrated as having a two-stage configuration including the first stack 52 and the second stack 53. However, the present invention is not limited to this and includes three or more stacks. It is good also as a structure of 3 steps | paragraphs or more. When the fuel cell stack 1 has an N-stage configuration including N stacks, the space facing the fuel outlet of the i-th stack (i is an integer not less than 1 and not more than N-1) and the fuel in the i + 1-th stack An inter-stack communication channel 61 that communicates with the space facing the inlet is provided in the separator 56 between the stacks.

  According to the third embodiment, the inter-stack communication channel 61 is not provided outside the fuel gas manifold, but is provided in the separator 56 between the stacks. The same effect as the embodiment can be obtained. Moreover, since the separator plate 56 does not need to be provided outside the fuel gas manifold, the size of the fuel cell can be further reduced.

(Fourth embodiment)
Next, a fourth embodiment of the present invention will be described with reference to FIGS.

  FIG. 14 is a perspective view showing an appearance of a fuel cell according to the fourth embodiment of the present invention.

  The fuel cell shown in FIG. 14 is a separator having a fuel electrode on one side and an oxidant electrode on the other side with an electrolyte in between, and a fuel gas flow path outside the fuel electrode of each electrode. And a fuel cell stack 71 in which unit cells in which separators having an oxidant gas flow path are arranged outside the oxidant electrode are arranged in a plurality of rows along the axial direction. Two stacks 73, a current collector 74 is provided outside the first stack 72, a current collector 75 is provided outside the second stack 73, and a separator 76 is provided between the stacks. As a fuel gas manifold having a gas chamber for supplying fuel gas to the fuel gas flow path of each unit cell of the fuel cell stack 71, a fuel inlet / return manifold 77 is provided on the fuel inlet side of the fuel cell stack 71. In addition, a fuel return / outlet manifold 78 is provided on the fuel outlet side, a fuel inlet pipe 79 is provided in the fuel inlet / return manifold 77, a fuel outlet pipe 80 is provided in the fuel return / outlet manifold 78, and In this configuration, the inter-stack communication channel is provided. Since the separator 76 of this embodiment needs to provide an inter-stack communication channel in its interior, a separator having a width slightly larger than the separators of the first and second embodiments is applied. To do. Note that the number of unit cells is smaller in the second stack 3 than in the first stack 2 (for example, a ratio of 65% to 35%).

  15 is a plan view showing the structure of the separator plate 76 provided in the fuel cell of FIG. 14 and the fuel gas flow.

  As shown in FIG. 15, the separator plate 76 has an inter-stack communication channel 81 therein. The inter-stack communication flow path 81 is formed along the surface of the separator plate 76 from the opening 82 in the lower portion of the edge on the fuel return / outlet manifold 78 side to the opening portion in the upper portion of the edge on the fuel inlet / return manifold 77 side. This is realized by a through hole penetrating to 83. The inter-stack communication channel 81 guides fuel gas from a low space in the fuel return / outlet manifold 78 to a high space in the fuel inlet / return manifold 77.

  16 (a) is a conceptual diagram showing the flow of fuel gas inside the first stack 72 provided in the fuel cell of FIG. 14 when viewed horizontally from the direction perpendicular to the longitudinal direction. (B) is a conceptual diagram showing the flow of the fuel gas inside when the second stack 73 provided in the fuel cell of FIG. 14 is viewed horizontally from the direction perpendicular to the longitudinal direction. FIG. 17A is a diagram showing the shape of the fuel inlet / return manifold 77 provided in the fuel cell of FIG. 14 when viewed horizontally from each stack side, and FIG. 14 is a view showing a shape of a fuel return / outlet manifold 78 provided in 14 fuel cells when viewed horizontally from each stack side. FIG.

  As shown in FIG. 16A, the first stack 72 has a first path 72A, a second path 72B, and a third path 72C as paths through which the fuel gas flows. As shown in FIG. 16B, the second stack 73 includes a first path 73A, a second path 73B, and a third path 73C as paths through which the fuel gas flows. As can be seen from FIGS. 16A and 16B, the first stack 72 and the second stack 73 have a common three-stage path configuration. Details of the fuel gas flow will be described later.

  As shown in FIG. 17 (a), the fuel inlet / return manifold 77 is divided into four spaces 77A, which are partitioned between the stacks and between some paths of the fuel gas. 77B, 77C, 77D. A fuel inlet pipe 79 is connected to the space 77A, and the inter-stack communication flow that communicates with the space 78B of the fuel return / outlet manifold 78 through the openings 83 and 82 provided in the separator plate 76 is connected to the space 77C. A path 81 is connected. The space 77A is opposed to the first path 72A of the first stack 72, the space 77B is opposed to the second path 72B and the third path 72C of the first stack 72, and the space 77C is the second path 72C. The space 73D is opposed to the second path 73B and the third path 73D of the second stack 73.

  On the other hand, as shown in FIG. 17 (b), the fuel return / outlet manifold 78 is divided into four spaces, which are partitioned between the stacks and between some paths of the fuel gas. 78A, 78B, 78C, 78D. The fuel outlet pipe 80 is connected to the space 78D, and the above-mentioned inter-stack communication flow communicating with the space 77C of the fuel inlet / return manifold 77 through the openings 82 and 83 provided in the separator plate 76 is connected to the space 78B. A path 81 is connected. The space 78A is opposed to the first path 72A and the second path 72B of the first stack 72, the space 78B is opposed to the third path 73C of the first stack 72, and the space 77C is the second path 72C. The first path 73A and the second path 73B of the stack 73 are opposed to each other, and the space 77D is opposed to the third path 73C of the second stack 73.

  Here, with reference to FIG. 15 thru | or FIG. 17, the fuel gas flow in this embodiment is demonstrated. During operation of the fuel cell system, fuel gas, oxidant gas, and cooling water are respectively supplied to the fuel cell stack 71, but only the flow of the fuel gas is shown here.

  When the fuel gas is supplied to the space 77A of the fuel inlet / return manifold 77 through the fuel inlet piping 79, the fuel gas passes through the first path 72A of the first stack 72, and the space 78A of the fuel return / outlet manifold 78. At the space 77B of the fuel inlet / return manifold 77, further through the third path 77C of the first stack 72, and through the fuel return / outlet manifold 78. Enter the space 78B. The fuel gas that has entered the space 78 </ b> B passes through the inter-stack communication flow path 81 through the opening 82 of the separator 76 and enters the space 77 </ b> C of the fuel inlet / return manifold 77 through the opening 83 of the separator 76. The fuel gas that has entered the space 77C passes through the first path 73A of the second stack 73, turns back in the space 78C of the fuel return / outlet manifold 78, passes through the second path 73B of the second stack 73, and passes through the fuel. It further turns back in the space 77D of the inlet / return manifold 77, passes through the third path 73C of the second stack 73, and enters the space 78D of the fuel return / outlet manifold 78. The fuel gas that has entered the space 78 </ b> D, that is, the fuel gas that has not been consumed in the fuel cell stack 71 is discharged from the fuel outlet pipe 80.

  In the present embodiment, the fuel cell stack 71 is illustrated as having a two-stage configuration including the first stack 72 and the second stack 73. However, the present invention is not limited to this and includes three or more stacks. It is good also as a structure of 3 steps | paragraphs or more. When the fuel cell stack 71 has an N-stage configuration including N stacks, the space facing the fuel outlet of the i-th stack (i is an integer not less than 1 and not more than N-1) and the fuel in the i + 1-th stack An inter-stack communication channel 81 that communicates with the space facing the inlet is provided in the separator plate 76 between the stacks.

  According to the fourth embodiment, even when another flow pattern different from that of the third embodiment is applied, the same effect as that of the third embodiment can be obtained.

(Supplementary items regarding the first to fourth embodiments)
The separator shown in each of the above-described embodiments is located between the first stack and the second stack, is exposed to a water vapor atmosphere, and adjacent stack components are corrosion resistant. Since it is a material, in order to prevent corrosion between different materials (galvanic corrosion) with the components of the stack, the material of the separator 6 is either a carbon plate or a mixed material obtained by adding a resin to carbon powder. It is desirable.

  Further, the fuel cell stack shown in each of the above-described embodiments can be applied to a fuel using a mixed gas containing hydrogen and other gases. In that case, the fuel consumed in the first stack is used. Since gas is introduced into the second stack, the hydrogen concentration in the fuel gas of the second stack is lower than that of the first stack, and the cell voltage of the second stack is slightly lower. In contrast, in the case of pure hydrogen fuel, the hydrogen concentration of the first stack and the second stack is maintained at almost 100% in the fuel cell stack shown in each embodiment. The characteristics are almost equal, and particularly effective for pure hydrogen fuel.

  Further, in the first embodiment and the second embodiment, the inter-stack communication flow path is provided outside the fuel gas manifold, but instead, the inter-stack communication flow path is provided inside the fuel gas manifold, Alternatively, the inter-stack communication channel may be realized by providing a through hole in the outer wall of the fuel gas manifold. For example, the communication channel may be formed by a short pipe on the side surface of the fuel gas manifold. In that case, it is desirable to consider so that the influence of moisture condensation is reduced.

(Fifth embodiment)
Next, a fifth embodiment of the present invention will be described with reference to FIG.

  FIG. 18 is a perspective view showing an appearance of a fuel cell system according to the fifth embodiment of the present invention.

  The fuel cell system shown in FIG. 18 includes a fuel cell 91 corresponding to any of the fuel cells shown in the first to fourth embodiments described above, and reforming the raw fuel into a hydrogen-rich gas. A reformer 92 that supplies gas to the fuel electrode 91 a of the fuel cell 91, an oxidant gas supply device 93 that supplies oxidant gas to the oxidant electrode 91 b of the fuel cell 91, and a coolant that cools the fuel cell 91. The apparatus includes a cooling device 94 that supplies and recovers the portion 91c and an electric control device 95 that supplies electricity extracted from the fuel cell 91 to the outside.

  In this configuration, raw fuel gas such as city gas is supplied to the reformer 92, and the reformed hydrogen-rich fuel gas is supplied to the fuel electrode 91 a of the fuel cell 91. Further, the oxidant gas is supplied to the oxidant electrode 91b by the oxidant gas supply device 93, and the coolant is supplied to the battery cooling unit 91c by the cooling device 94. Electricity obtained by supplying the fuel gas and the oxidant gas is supplied to the outside of the fuel cell system by the electric control device 95.

  According to the fifth embodiment, it is possible to realize a fuel cell system that takes advantage of the advantages of the fuel cells shown in the first to fourth embodiments.

(Sixth embodiment)
Next, a sixth embodiment of the present invention will be described with reference to FIG.

  In the sixth embodiment, parts that are the same as those in the configuration of the fifth embodiment shown in FIG. 19 are given the same reference numerals, and redundant descriptions are omitted. Below, it demonstrates centering on a different part from 5th Embodiment.

  FIG. 19 is a perspective view showing an appearance of a fuel cell system according to the sixth embodiment of the present invention.

  The fuel cell system shown in FIG. 19 includes a pure hydrogen gas supply device 96 in place of the reforming device 13 described above. The pure hydrogen gas supply device 96 supplies pure hydrogen gas to the fuel electrode 91 a of the fuel cell 91.

  When pure hydrogen gas is used as the fuel gas, the hydrogen concentration is 100% in any stack group consisting of multiple stages, and there is no difference in the composition of the fuel gas between the stacks. It becomes possible to drive at.

  According to the sixth embodiment, when pure hydrogen gas is used as the fuel gas, it is possible to realize a fuel cell system that further utilizes the advantages of the fuel cells shown in the first to fourth embodiments. Become.

  The present invention is not limited to the above-described embodiments as they are, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. In addition, various inventions can be formed by appropriately combining a plurality of components disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, constituent elements over different embodiments may be appropriately combined.

1, 31, 51, 71 ... Fuel cell stack 2, 32, 52, 72 ... First stack 3, 33, 53, 73 ... Second stack 4, 5, 34, 35, 54, 55, 74, 75 ... Current collector plate 6, 36, 56, 76 ... Separator plate 7, 37 ... Fuel inlet / outlet manifold 8, 38 ... Fuel return manifold 57, 77 ... Fuel inlet / return manifold 58, 78 ... Fuel return / outlet manifold 9, 39, 59, 79 ... Fuel inlet piping 10, 40, 60, 80 ... Fuel outlet piping 11, 41, 61, 81 ... Inter-stack communication channel 12, 13, 42, 43, 62, 63, 82, 83 ... Opening Part 14 ... Space 15, 16 ... Lid attachment part 17, 18 ... Communication channel lid O-ring 19, 20 ... Connection channel lid fastening part 91 ... Fuel cell 92 ... Reformer 93 ... Oxidant gas supply device 4 ... cooling device 95 ... electric control apparatus 96 ... pure hydrogen gas supply device

Claims (8)

A fuel cell stack in which unit cells are arranged in a plurality of rows along the axial direction has an N-stage configuration composed of N stacks, separators are provided between the stacks, and the fuel cells are disposed on both side surfaces of the fuel cell stack. In a fuel cell provided with first and second fuel gas manifolds having gas chambers for supplying fuel gas to the fuel gas flow path of each unit cell of the stack,
The first and second fuel gas manifolds include a plurality of spaces partitioned at least between the stacks,
The inter-stack communication flow that connects the first space facing the fuel outlet of the i-th stack (i is an integer of 1 or more and N-1 or less) and the second space facing the fuel inlet of the i + 1-th stack. A fuel cell, wherein a path is provided in at least one of the first and second fuel gas manifolds. Each stack has a multi-stage path through which fuel gas flows,
At least one of the first and second fuel gas manifolds includes a plurality of spaces that are partitioned not only between the stacks but also at least part of the paths,
2. The inter-stack communication flow path guides fuel gas from a low space in the first fuel gas manifold to a high space in the first fuel gas manifold. The fuel cell as described. The first fuel gas manifold has a first opening that communicates from the first space to the outside of the fuel gas manifold, and a second opening that communicates from the second space to the outside of the fuel gas manifold. Have
The inter-stack communication flow path has a lid attached to the outside of the fuel gas manifold so that a space connecting the first opening and the second opening is sealed outside the fuel gas manifold. The fuel cell according to claim 1, wherein the fuel cell is realized. A fuel cell stack in which unit cells are arranged in a plurality of rows along the axial direction has an N-stage configuration composed of N stacks, separators are provided between the stacks, and the fuel cells are disposed on both side surfaces of the fuel cell stack. In a fuel cell provided with first and second fuel gas manifolds having gas chambers for supplying fuel gas to the fuel gas flow path of each unit cell of the stack,
The first and second fuel gas manifolds include a plurality of spaces partitioned at least between the stacks,
The inter-stack communication flow that connects the first space facing the fuel outlet of the i-th stack (i is an integer of 1 or more and N-1 or less) and the second space facing the fuel inlet of the i + 1-th stack. A fuel cell, wherein a path is provided in the separator. Each stack has a multi-stage path through which fuel gas flows,
At least one of the first and second fuel gas manifolds includes a plurality of spaces that are partitioned not only between the stacks but also at least part of the paths,
5. The inter-stack communication channel guides fuel gas from a low space in the first fuel gas manifold to a high space in the second fuel gas manifold. The fuel cell as described.   5. The inter-stack communication flow path is realized by a through-hole penetrating from a part of the edge of the separator plate to a part of another edge along the surface of the separator plate. Or 5. The fuel cell according to 5.   The fuel cell according to any one of claims 1 to 6, reforming means for reforming raw fuel into a hydrogen-rich gas and supplying the reformed gas to the fuel cell, and oxidizing gas as the fuel An oxidant gas supply means for supplying a battery, a cooling means for supplying and recovering a coolant to the fuel cell, and an electric control means for supplying the electricity extracted from the fuel cell to the outside. Fuel cell system.   7. The fuel cell according to claim 1, a pure hydrogen gas supply means for supplying pure hydrogen gas to the fuel cell, and an oxidant gas supply means for supplying oxidant gas to the fuel cell. A fuel cell system comprising: cooling means for supplying and recovering a coolant to the fuel cell; and electric control means for supplying electricity extracted from the fuel cell to the outside.

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