JP2008176986A - Fuel cell and fuel cell system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel cell inhibiting drop in system efficiency and efficiently removing retention water in a gas passage. <P>SOLUTION: The fuel cell 200 has a stack formed by stacking a plurality of cells in which the gas passage is installed, supply manifolds 80a, 80c connected to the gas passage and supplying gas to the gas passage, and exhausting manifolds 80b, 80d connected to the gas passage and exhausting gas from the gas passage are installed in the stack, and flow velocity of gas supplied from the supply manifolds 80a, 80c to the gas passage of at least one end cell 12 of the stack is made higher than the average flow velocity of gas supplied from the supply manifolds 80a, 80c to each gas passage in the stack. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a fuel cell and a fuel cell system.

  A fuel cell is a device that generally obtains electric energy using hydrogen and oxygen as fuel. Since this fuel cell is excellent in terms of the environment and can realize high energy efficiency, it has been widely developed as a future energy supply system.

  Examples of the fuel cell using a solid electrolyte include a solid polymer fuel cell and a solid oxide fuel cell. Among these, the polymer electrolyte fuel cell has a stack structure in which a plurality of cells each having a membrane electrode assembly (MEA) in which a solid polymer electrolyte membrane is sandwiched between a cathode and an anode and further sandwiched between separators are stacked. In a polymer electrolyte fuel cell, fuel gas is supplied to the anode and oxidant gas is supplied to the cathode. As a result, the fuel gas and the oxidant gas undergo an electrochemical reaction to generate water. The fuel cell generates electricity by taking out the current generated when the water is generated.

  The water generated by the power generation of the fuel cell is discharged to the outside mainly through the reaction gas flow path in the fuel cell. However, some of the generated water may stay in the reaction gas flow path. In particular, the generated water tends to stay in the end cells. This is because the end cell has a large heat dissipation amount. If water stays in the reaction gas flow path, the diffusibility of the reaction gas decreases. In this case, the power generation performance of the fuel cell may be reduced. Therefore, as a method for suppressing the retention of the generated water, a method of flowing a dry scavenging gas into the reaction gas channel when the fuel cell is stopped is considered (for example, see Patent Document 1).

  Patent Document 1 discloses a method of removing stagnant water by flowing a larger amount of scavenging gas than normal scavenging when it is determined that the stagnant water is in the flow path.

JP 2006-4904 A

  However, in the scavenging method according to Patent Document 1, since it is necessary to flow a large amount of scavenging gas, the load on the compressor increases and the system efficiency of the fuel cell system decreases. In addition, a special control device for flowing a large amount of scavenging gas is also required.

  An object of this invention is to provide the fuel cell which can suppress a system efficiency fall and can remove efficiently the stagnant water in a gas flow path.

  A fuel cell according to the present invention includes a stack in which a plurality of cells each provided with a gas flow path are stacked. The stack includes a supply manifold connected to the gas flow path and supplying gas to the gas flow path. A discharge manifold connected to the flow path for discharging gas from the gas flow path, and the flow rate of the gas supplied from the supply manifold to the gas flow path of at least one end cell of the stack depends on each flow rate in the stack. The gas flow rate is larger than the average flow velocity of the gas supplied from the supply manifold. According to the fuel cell of the present invention, the flow rate of the gas passing through the gas flow path of the end cell is larger than the average flow speed of the gas flow path in the stack. Thereby, it is possible to efficiently remove the stagnant water in the gas flow path. Further, since it is not necessary to increase the amount of scavenging gas, it is possible to suppress a decrease in system efficiency.

  In the above configuration, the gas flow path of the end cell may be a single flow path from the supply manifold to the discharge manifold. According to this configuration, even if the generated water is retained in any part of the end cell, the retained water can be efficiently discharged from the end cell.

  In the above configuration, the supply manifold includes a first supply manifold and a second supply manifold, the discharge manifold includes a first discharge manifold and a second discharge manifold, the first supply manifold, the first discharge manifold, the second The supply manifold and the second discharge manifold communicate with each other in order, and the second supply manifold may be connected to at least the end cell.

  In the above configuration, the second supply manifold is connected to a plurality of adjacent cells continuously from the end cell, and the number of cells to which the second supply manifold is connected is the number of cells to which the first supply manifold is connected. It may be characterized by being small compared to.

  In the above configuration, the supply manifold includes a first supply manifold and a second supply manifold, the discharge manifold includes a first discharge manifold and a second discharge manifold, the first supply manifold, the first discharge manifold, the second The supply manifold and the second discharge manifold are communicated in this order, and the first supply manifold may be connected to at least the end cell.

  In the above configuration, the first supply manifold is connected to a plurality of cells that are continuously adjacent from the end cell, and the number of cells to which the first supply manifold is connected is the number of cells to which the second supply manifold is connected. It may be characterized by being small compared to.

  In the above configuration, the end cell may be a minus side end cell. According to this configuration, the accumulated water in the gas flow path of the minus side end cell can be efficiently removed.

  A fuel cell system according to the present invention includes a fuel cell according to any one of claims 1 to 7, a scavenging gas supply means for supplying a scavenging gas to a gas flow path, and a detection means for detecting an electrical resistance of an end cell. And a control means for controlling the scavenging gas supply means so that the scavenging gas is supplied to the gas flow path until the detection result of the detection means reaches a predetermined value or more. According to the fuel cell system of the present invention, the flow rate of the gas passing through the gas flow path of the end cell is larger than the average flow speed of the gas flow path in the stack. Thereby, it is possible to efficiently remove the stagnant water in the gas flow path. Further, since it is not necessary to increase the amount of scavenging gas, it is possible to suppress a decrease in system efficiency.

  In the above configuration, the gas flow path may further include a reaction gas supply unit that supplies the reaction gas in a direction opposite to the scavenging gas.

  ADVANTAGE OF THE INVENTION According to this invention, the fuel cell which can suppress a stagnant water in a gas flow path while being able to suppress a system efficiency fall can be provided.

  Hereinafter, the best mode for carrying out the present invention will be described.

  First, the entire fuel cell system 300 including the fuel cell 200 according to the first embodiment of the present invention will be described. FIG. 1 is a block diagram showing the configuration of the fuel cell system 300. As shown in FIG. 1, the fuel cell system 300 includes a reaction gas supply unit 40, a scavenging gas supply unit 50, a detection unit 60, a control unit 70, and a fuel cell 200.

  The fuel cell 200 has a stack structure in which a plurality of cells 10 are stacked. An end plate 20 is disposed at one end of the stacked body of the cells 10, and an end plate 22 is disposed at the other end. Each of the end plates 20 and 22 is connected to a pipe for supplying a reaction gas or the like to each cell 10.

  The reactive gas supply means 40 includes a fuel gas supply means (not shown) and an oxidant gas supply means (not shown). The fuel gas supply means is means for supplying fuel gas to the fuel cell 200. The oxidant gas supply means is means for supplying oxidant gas to the fuel cell 200. For example, hydrogen is used as the fuel gas. As the oxidant gas, for example, air containing oxygen is used. Hereinafter, fuel gas and oxidant gas are collectively referred to as reaction gas. The reactive gas supply means 40 supplies the reactive gas to the gas flow path of each cell 10 from the end plate 22 side in accordance with an instruction from the control means 70. Thereby, power generation is performed in each cell 10.

  The scavenging gas supply means 50 is means for supplying scavenging gas to the fuel cell 200. The scavenging gas is not particularly limited, but dry reaction gas or the like is used. The scavenging gas supply means 50 supplies the scavenging gas from the end plate 20 side to the gas flow path of each cell 10 according to the instruction of the control means 70. Thereby, the water staying in the gas flow path of each cell 10 is removed.

  The detection means 60 detects the electric resistance value of the cell 10 and transmits the detection result to the control means 70. The control means 70 comprises a CPU (Central Processing Unit), ROM (Read Only Memory), RAM (Random Access Memory) and the like. The control means 70 controls the reaction gas supply means 40 and the scavenging gas supply means 50 based on the detection result of the detection means 60.

  FIG. 2 shows a schematic cross-sectional view of the cell 10. As shown in FIG. 2, the cell 10 has a structure in which a separator 110a, a diffusion layer 108a, a cathode catalyst layer 104, an electrolyte membrane 102, an anode catalyst layer 106, a diffusion layer 108b, and a separator 110b are sequentially stacked. The electrolyte membrane 102 is made of a solid polymer electrolyte having proton conductivity, for example, a perfluorosulfonic acid polymer.

  The cathode catalyst layer 104 is a catalyst layer that promotes the reaction between protons and oxygen. The anode catalyst layer 106 is a catalyst layer that promotes protonation of hydrogen. The cathode catalyst layer 104 and the anode catalyst layer 106 are made of, for example, platinum-supported carbon. The diffusion layer 108a is a layer that transmits an oxidant gas containing oxygen. The diffusion layer 108b is a layer that transmits a fuel gas containing hydrogen. The diffusion layers 108a and 108b are made of, for example, carbon paper. An oxidant gas flow path 90 is provided in the separator 110a. A fuel gas channel 91 is provided in the separator 110b.

  Fuel gas is supplied to the fuel gas passage 91 from the fuel gas supply means. The fuel gas passes through the diffusion layer 108b and reaches the anode catalyst layer 106. Hydrogen contained in the fuel gas is dissociated into protons and electrons via the catalyst of the anode catalyst layer 106. The protons conduct through the electrolyte membrane 102 and reach the cathode catalyst layer 104.

  Oxidant gas is supplied to the oxidant gas flow path 90 from the oxidant gas supply means. The oxidant gas passes through the diffusion layer 108a and reaches the cathode catalyst layer 104. In the cathode catalyst layer 104, protons and oxygen react via the catalyst. Thereby, power generation is performed and water is generated. The water generated by the power generation is discharged to the outside mainly through the oxidant gas channel 90 and the fuel gas channel 91.

  Next, the manifold formed in the fuel cell 200 and the gas flow path formed in each cell 10 will be described. In order to simplify the description, the manifold and gas flow path through which the oxidant gas flows will be described. FIG. 3A is a schematic diagram of a manifold and a gas flow path through which the oxidant gas flows. For example, as shown in FIG. 3A, it is assumed that the fuel cell 200 has a stack structure in which 10 layers of cells 10 are stacked. The cell 10 at the end of the fuel cell 200 on the end plate 20 side is referred to as an end cell 12. The oxidant gas flow paths of the cells 10 other than the end cells 12 are respectively referred to as oxidant gas flow paths 90a, and the oxidant gas flow paths of the end cells 12 are referred to as oxidant gas flow paths 90b.

  The fuel cell 200 is provided with a supply manifold and a discharge manifold. The supply manifold is a manifold for supplying oxidant gas to the oxidant gas flow path. The supply manifold includes a manifold 80a and a manifold 80c. The manifold 80a is a manifold for supplying an oxidant gas to each oxidant gas flow path 90a. The manifold 80 c is a manifold for supplying an oxidant gas to the oxidant gas flow path 90 b and is connected to the end cell 12.

  The discharge manifold is a manifold for discharging the oxidant gas from the oxidant gas flow path. The discharge manifold includes a manifold 80b and a manifold 80d. The manifold 80b is a manifold for discharging the oxidant gas from each oxidant gas flow path 90a. The manifold 80d is a manifold for discharging the oxidant gas from the oxidant gas flow path 90b.

  Each manifold communicates in the order of a manifold 80a, a manifold 80b, a manifold 80c, and a manifold 80d. The manifold 80b is connected to the manifold 80c without passing through the oxidant gas flow path. The oxidant gas is supplied from the manifold 80a, passes through each oxidant gas flow path 90a, the manifold 80b, the manifold 80c, and the oxidant gas flow path 90b, and is discharged from the manifold 80d. In Fig.3 (a), the flow direction of oxidizing gas is shown by the arrow.

  In this case, the oxidant gas flowing through each oxidant gas flow path 90a is collected and flows through the oxidant gas flow path 90b. As a result, the flow rate of the oxidant gas flowing through the oxidant gas flow channel 90b is larger than the flow rate of the oxidant gas flowing through each oxidant gas flow channel 90a. Therefore, the flow rate of the oxidant gas flowing through the oxidant gas flow channel 90b is larger than the average flow rate of the oxidant gas flowing through the gas flow channels of the fuel cell 200. As a result, moisture remaining in the end cell 12 is efficiently removed.

  Subsequently, in the fuel cell 200 of FIG. 3A, a schematic diagram of the manifold and the gas flow path when the scavenging gas is supplied in the direction opposite to the oxidant gas is shown in FIG. As the scavenging gas in this case, for example, dry air can be used. The scavenging gas is supplied from the manifold 80d, passes through the oxidant gas flow path 90b, the manifold 80c, the manifold 80b, and each oxidant gas flow path 90a, and is discharged from the manifold 80a. In FIG. 3B, the flow direction of the scavenging gas is indicated by an arrow.

  The flow rate of the scavenging gas flowing through the oxidant gas flow channel 90b is larger than the flow rate of the scavenging gas flowing through the oxidant gas flow channel 90a. Therefore, the flow rate of the scavenging gas flowing through the oxidant gas flow channel 90b is larger than the average flow rate of the scavenging gas flowing through each gas flow channel of the fuel cell 200. As a result, moisture remaining in the end cell 12 is efficiently removed. Further, since the dried scavenging gas is supplied to the oxidant gas flow channel 90b before the oxidant gas flow channel 90a, the drying of the oxidant gas flow channel 90b is promoted. In this case, freezing of generated water in a low temperature environment such as below freezing point is suppressed. As a result, the startability of the fuel cell 200 is improved.

  According to the fuel cell 200 according to the present embodiment, when a normal amount of scavenging gas flows, the flow rate of the scavenging gas flowing through the oxidant gas flow path 90b of the end cell 12 is set to each gas flow path of the fuel cell 200. It becomes larger than the average flow velocity of the scavenging gas flowing through the. As a result, it is possible to efficiently remove the accumulated water in the oxidant gas flow path 90b of the end cell 12. Therefore, the accumulated water in the end cell 12 can be efficiently removed without increasing the total amount of the scavenging gas. As a result, a decrease in system efficiency of the fuel cell system 300 can be suppressed. Further, it is not necessary to provide a special device for increasing the total amount of scavenging gas.

  Next, the operation of the fuel cell system 300 will be described. FIG. 4 shows a flowchart from start to stop of the fuel cell system 300. When the switch of the fuel cell system 300 is turned on, the control means 70 controls the reaction gas supply means 40 so as to supply the reaction gas to the fuel cell 200 (step S1). When the reactive gas is supplied to the fuel cell 200, water is generated from hydrogen and oxygen in each cell 10 by an electrochemical reaction, and electric power is generated accordingly, and power generation is started (step S2).

  Next, the control means 70 determines whether or not there is a power generation stop signal (step S3). When the control means 70 determines that there is no power generation stop signal, the control means 70 continues the power generation as it is. On the other hand, when the control means 70 determines that there is a power generation stop signal, the control means 70 stops the power generation of the fuel cell 200 (step S4). Next, the control means 70 controls the scavenging gas supply means 50 so as to supply the scavenging gas to the fuel cell 200 (step S5).

Subsequently, the control means 70 receives the electrical resistance value of the end cell 12 from the detection means 60 (step S6). Subsequently, the control means 70 determines whether or not the electrical resistance value of the end cell 12 is greater than a predetermined value (for example, 500 mΩ · cm ² ) (step S7). In this case, it can be determined whether the accumulated water in the end cell 12 has been removed. Note that it is possible to estimate the amount of accumulated water in the end cell 12 not only by detecting the electric resistance value of the end cell 12 but also the electric resistance value of the entire stack.

  If it is not determined in step S7 that the electrical resistance value of the end cell 12 is greater than the predetermined value, the control means 70 executes step S6. On the other hand, when it is determined in step S7 that the electrical resistance value of the end cell 12 is larger than the predetermined value, the control means 70 controls the scavenging gas supply means 50 so as to stop the scavenging gas supply (step S7). S8). Thereafter, the control means 70 ends the execution of the flowchart.

  In this embodiment, as an example of the manifold and the gas flow path, the manifold and the gas flow path in which the oxidant gas flows are shown. However, the manifold and the gas flow path in which the fuel gas flows are as in the present embodiment. It may have a simple channel structure. Furthermore, both the manifold and the gas flow path in which the oxidant gas flows and the manifold and the gas flow path in which the fuel gas flow may have a flow path structure as in this embodiment.

  In this embodiment, the scavenging gas may be flowed in the same direction as the reaction gas. That is, in the fuel cell 200 shown in FIG. 3A, a scavenging gas may be flowed instead of the oxidant gas. Even in this case, the flow rate of the scavenging gas passing through the oxidant gas flow path 90b of the end cell 12 is larger than the average flow speed of the scavenging gas flowing through each gas flow path of the fuel cell 200. As a result, it is possible to efficiently remove the accumulated water in the oxidant gas flow path 90b of the end cell 12.

  Further, the end cell 12 is preferably provided at the minus end of the fuel cell 200. This is because the generated water tends to stay in the minus end cell as compared with the plus end cell of the fuel cell 200.

  In the present embodiment, the manifold 80 c may be connected to a plurality of adjacent cells 10 that are continuously adjacent to the end cell 12. Even in this case, when the number of cells 10 to which the manifold 80c is connected is smaller than the number of cells 10 to which the manifold 80a is connected, the oxidant gas flow path 90b of the end cell 12 flows. The gas flow rate is greater than the average flow rate of the gas flowing through each gas flow path of the fuel cell 200. For example, in the case of the fuel cell 200 in which 100 layers of cells 10 are stacked, the manifold 80 c may be connected to about 20 layers of cells 10 that are continuously adjacent to the end cell 12.

  In the correspondence relationship between FIG. 3A of this embodiment and claim 3, the manifold 80a corresponds to the first supply manifold, the manifold 80b corresponds to the first discharge manifold, and the manifold 80c corresponds to the second supply manifold. The manifold 80d corresponds to the second discharge manifold. Further, in the correspondence relationship between FIG. 3B of this embodiment and claim 5, the manifold 80 d corresponds to the first supply manifold, the manifold 80 c corresponds to the first discharge manifold, and the manifold 80 b corresponds to the second supply manifold. The manifold 80a corresponds to the second discharge manifold.

(Modification 1)
Further, in this embodiment, the flow velocity of the gas flowing through the gas flow paths of both the negative side and positive side end cells may be larger than the average flow speed of each gas flow path in the stack. 5 (a) and 5 (b), a fuel in which the flow velocity of the gas flowing through the gas flow paths of the negative side end cell and the positive side end cell is larger than the average flow speed of each gas flow path in the stack. The schematic diagram of the manifold and gas flow path of the battery 200a is shown.

  FIG. 5A is a schematic diagram when the oxidizing gas flows, and FIG. 5B is a schematic diagram when the scavenging gas flows. In FIG. 5A, the minus side end cell 10 of the fuel cell 200 a is referred to as an end cell 12, and the plus side end cell 10 is referred to as an end cell 13. The oxidant gas flow path of the end cell 13 is called an oxidant gas flow path 90a, and the oxidant gas flow paths of the cells 10 other than the end cell 12 and the end cell 13 are respectively oxidant gas flow paths 90b. The oxidant gas flow path of the end cell 12 is referred to as an oxidant gas flow path 90c.

  The supply manifold includes a manifold 81a, a manifold 81c, and a manifold 81e. The manifold 81 a is a manifold for supplying an oxidant gas to the oxidant gas flow path 90 a and is connected to the end cell 13. The manifold 81c is a manifold for supplying an oxidant gas to each oxidant gas flow path 90b. The manifold 81 e is a manifold for supplying an oxidant gas to the oxidant gas flow path 90 c and is connected to the end cell 12.

  The discharge manifold includes a manifold 81b, a manifold 81d, and a manifold 81f. The manifold 81b is a manifold for discharging the oxidant gas from the oxidant gas flow path 90a. The manifold 81d is a manifold for discharging the oxidant gas from each oxidant gas flow path 90b. The manifold 81f is a manifold for discharging the oxidant gas from the oxidant gas flow path 90c.

  Each manifold communicates in the order of a manifold 81a, a manifold 81b, a manifold 81c, a manifold 81d, a manifold 81e, and a manifold 81f. The manifold 81b is connected to the manifold 81c without passing through the oxidant gas flow path. Furthermore, the manifold 81d is connected to the manifold 81e without passing through the oxidant gas flow path. The oxidant gas is supplied from the manifold 81a, passes through the oxidant gas flow path 90a, passes through the manifold 81b, the manifold 81c, each oxidant gas flow path 90b, the manifold 81d, the manifold 81e, and the oxidant gas flow path 90c, and forms the manifold 81f. Is discharged to the outside. In Fig.5 (a), the flow direction of oxidizing gas is shown by the arrow.

  Further, as shown in FIG. 5B, the scavenging gas is supplied from the manifold 81f, and the oxidizing gas channel 90c, the manifold 81e, the manifold 81d, each oxidizing gas channel 90b, the manifold 81c, the manifold 81b, and the oxidizing gas. It passes through the agent gas flow path 90a and is discharged from the manifold 81a to the outside.

  As shown in FIG. 5A, according to the flow path structure of the fuel cell 200a, the entire amount of the oxidant gas flows through the oxidant gas flow path 90a. Further, the oxidant gas flowing through each oxidant gas flow path 90b is collected and flows through the oxidant gas flow path 90c. Thereby, the flow rate of the oxidant gas flowing through the oxidant gas flow channel 90a and the oxidant gas flow channel 90c is larger than the average flow rate of the oxidant gas flowing through each gas flow channel of the fuel cell 200a. As a result, moisture remaining in the end cell 12 and the end cell 13 is efficiently removed.

  Further, as shown in FIG. 5 (b), according to the flow path structure of the fuel cell 200a, the flow rate of the scavenging gas flowing through the oxidant gas flow path 90a and the oxidant gas flow path 90c is different from that of the fuel cell 200a. It becomes larger than the average flow velocity of the scavenging gas flowing in the gas flow path. As a result, moisture remaining in the end cell 12 and the end cell 13 is efficiently removed. In this case, freezing of generated water in a low temperature environment such as below freezing point is suppressed. As a result, the startability of the fuel cell 200a is improved.

  In the fuel cell 200a, the manifold 81e may be connected to a plurality of cells 10 adjacent to the end cell 12 continuously. Even in this case, when the number of cells 10 to which the manifold 81e is connected is smaller than the number of cells 10 to which the manifold 81c is connected, the oxidant gas flow path 90c of the end cell 12 flows. The gas flow rate is larger than the average flow rate of the gas flowing through each gas flow path of the fuel cell 200a.

  Further, in the fuel cell 200a, the manifold 81a may be connected to a plurality of adjacent cells 10 continuously from the end cell 13. Even in this case, when the number of cells 10 to which the manifold 81a is connected is smaller than the number of cells 10 to which the manifold 81c is connected, the oxidant gas flow path 90a of the end cell 13 flows. The gas flow rate is larger than the average flow rate of the gas flowing through each gas flow path of the fuel cell 200a.

  Further, in the fuel cell 200a, the manifold 81e is connected to a plurality of adjacent cells 10 continuously from the end cell 12, and the manifold 81a is connected to a plurality of adjacent cells 10 continuously from the end cell 13. It may be. Even in this case, when the total number of the plurality of cells 10 to which the manifold 81e is connected and the plurality of cells 10 to which the manifold 81a is connected is smaller than the number of the cells 10 to which the manifold 81c is connected, The flow rate of the gas flowing through the oxidant gas flow paths 90c and 90a of the end cell 12 and the end cell 13 is larger than the average flow rate of the scavenging gas flowing through the gas flow paths of the fuel cell 200a. For example, in the case of a fuel cell 200a in which 100 layers of cells 10 are stacked, the manifold 81a and the manifold 81e may be connected to the 20 layers of cells 10, respectively.

  In the correspondence relationship between FIG. 5A of this modification and claim 3, the manifold 81c corresponds to the first supply manifold, the manifold 81d corresponds to the first discharge manifold, and the manifold 81e corresponds to the second supply manifold. The manifold 81f corresponds to the second discharge manifold. Further, in the correspondence relationship between FIG. 5B of this modification and claim 5, the manifold 81f corresponds to the first supply manifold, the manifold 81e corresponds to the first discharge manifold, and the manifold 81d corresponds to the second supply manifold. The manifold 81c corresponds to the second discharge manifold.

  Subsequently, a fuel cell 200b according to a second embodiment of the present invention will be described. FIG. 6A is a schematic diagram of a manifold and a gas flow path in which the oxidant gas of the fuel cell 200b according to the second embodiment flows. Unlike the fuel cell 200 shown in FIG. 3A, the fuel cell 200b shown in FIG. 6A includes an end cell 12b instead of the end cell 12, and a manifold 82a instead of the manifold 80a. A manifold 82b is provided instead of 80b. The end cell 12b includes an oxidant gas flow path 91b instead of the oxidant gas flow path 90b. FIG. 6B shows a schematic diagram of the manifold and the gas flow path when the scavenging gas is supplied in the direction opposite to the oxidant gas in the fuel cell 200b of FIG. 6A. Since other configurations are the same as those of the fuel cell 200 according to the first embodiment, the description thereof is omitted.

  As shown in FIGS. 6 (a) and 6 (b), the manifold 82a and the manifold 82b are each connected to each cell 10 constituting the fuel cell 200b including the end cell 12b. In FIG. 6A, the oxidant gas is supplied from the manifold 82a, passes through each oxidant gas flow path 90a and the oxidant gas flow path 91b, and is discharged from the manifold 82b to the outside. In FIG. 6B, the scavenging gas is supplied from the manifold 82b, passes through the oxidant gas flow paths 90a and the oxidant gas flow paths 91b, and is discharged from the manifold 82a to the outside.

  Next, the oxidant gas flow path 91b of the fuel cell 200b will be described. FIG. 7A is a schematic plan view of the end cell 12b in FIG. 6B. As shown in FIG. 7A, the oxidant gas flow path 91b of the end cell 12b has a single flow path (hereinafter referred to as a single flow path) extending in a meandering manner from the manifold 82a to the manifold 82b. Is formed. In FIG. 7A, the scavenging gas is supplied from the manifold 82b, passes through the oxidant gas passage 91b, and is discharged from the manifold 82a to the outside.

  On the other hand, FIG. 7B shows a schematic plan view of the cells 10 other than the end cell 12b in FIG. 6B. In FIG. 7B, a plurality of oxidant gas flow paths 90 a are formed in the cell 10. In FIG. 7B, the scavenging gas is supplied from the manifold 82b, passes through each oxidant gas flow path 90a, and is discharged from the manifold 82a to the outside.

  In this case, the flow rate of the scavenging gas flowing through the oxidant gas flow path 91b shown in FIG. 7A is compared with the flow rate of the scavenging gas flowing through each oxidant gas flow path 90a shown in FIG. ,growing. That is, since the gas flow path of the end cell 12b is a single flow path, the flow rate of the gas flowing through the gas flow path of the end cell 12b is greater than the average flow rate of the gas flowing through each oxidant gas flow path 90a. Also grows. Therefore, the flow rate of the oxidant gas flowing through the oxidant gas flow channel 91b is larger than the average flow rate of the oxidant gas flowing through each gas flow channel of the fuel cell 200b. Thereby, the water | moisture content which retains in the edge part cell 12b is removed efficiently.

  If the oxidant gas flow path 91b is a single flow path, the scavenging gas supplied from the manifold 82b flows through the oxidant gas flow path 91b formed in the end cell 12b and then is discharged to the manifold 82a. Is done. Therefore, even if the generated water stays in any part of the end cell 12b, the generated water can be efficiently discharged from the end cell 12b.

  The oxidant gas channel 91b may include two or more channels. Also in this case, the number of the oxidant gas flow paths 91b is set so that the flow rate of the scavenging gas flowing through the oxidant gas flow path 91b is larger than the average flow rate of the scavenging gas flowing through each gas flow path of the fuel cell 200b. If it is limited, the effect of the present invention can be obtained. Further, in the fuel cell 200 shown in FIGS. 3A and 3B, the oxidant gas flow path 90b of the end cell 12 may be a single flow path. Further, in the fuel cell 200a shown in FIGS. 5A and 5B, the oxidant gas flow path 90b of the end cell 12 and the oxidant gas flow path 90a of the end cell 13 are each one flow path. It may be.

  In the correspondence relationship between FIG. 6A of this modification and claim 1, the manifold 82a corresponds to the supply manifold, and the manifold 82b corresponds to the discharge manifold. Further, in the correspondence relationship between FIG. 6B of this embodiment and claim 1, the manifold 82b corresponds to the supply manifold, and the manifold 82a corresponds to the discharge manifold.

1 is a schematic diagram of a fuel cell system according to a first embodiment of the present invention. It is a schematic diagram of the cell which concerns on 1st Example. It is a schematic diagram of the flow path structure of the fuel cell according to the first embodiment. 2 is a flowchart of the fuel cell system according to the first embodiment. It is a schematic diagram of the flow path structure of the fuel cell which concerns on the modification 1 of 1st Example. It is a schematic diagram of the flow-path structure of the fuel cell which concerns on 2nd Example. It is a typical top view of the cell of the fuel cell concerning the 2nd example.

Explanation of symbols

10 cells 12 end cells 40 reactive gas supply means 50 scavenging gas supply means 60 detection means 70 control means 80a manifold 80b manifold 80c manifold 80d manifold 90a gas flow path 90b gas flow path 200 fuel cell 300 fuel cell system

Claims (9)

A stack in which a plurality of cells provided with gas flow paths are stacked,
The stack includes a supply manifold connected to the gas flow path for supplying gas to the gas flow path, and a discharge manifold connected to the gas flow path for discharging the gas from the gas flow path. Provided,
The flow rate of the gas supplied from the supply manifold to the gas flow path of at least one end cell of the stack is larger than the average flow rate of the gas supplied from the supply manifold to each gas flow path in the stack. The fuel cell characterized by the above-mentioned. 2. The fuel cell according to claim 1, wherein the gas flow path of the end cell is a single flow path from the supply manifold to the discharge manifold. The supply manifold includes a first supply manifold and a second supply manifold,
The discharge manifold includes a first discharge manifold and a second discharge manifold,
The first supply manifold, the first discharge manifold, the second supply manifold, and the second discharge manifold communicate in this order,
The fuel cell according to claim 1, wherein the second supply manifold is connected to at least the end cell. The second supply manifold is connected to a plurality of adjacent cells continuously from the end cell,
4. The fuel cell according to claim 3, wherein the number of cells connected to the second supply manifold is smaller than the number of cells connected to the first supply manifold. The supply manifold includes a first supply manifold and a second supply manifold,
The discharge manifold includes a first discharge manifold and a second discharge manifold,
The first supply manifold, the first discharge manifold, the second supply manifold, and the second discharge manifold communicate in this order,
The fuel cell according to claim 1, wherein the first supply manifold is connected to at least the end cell. The first supply manifold is connected to a plurality of adjacent cells continuously from the end cell,
6. The fuel cell according to claim 5, wherein the number of the cells connected to the first supply manifold is smaller than the number of the cells connected to the second supply manifold. The fuel cell according to claim 1, wherein the end cell is a negative end cell. A fuel cell according to any one of claims 1 to 7,
A scavenging gas supply means for supplying a scavenging gas to the gas flow path;
Detecting means for detecting an electrical resistance of the end cell;
A fuel cell system comprising: control means for controlling the scavenging gas supply means so that the scavenging gas is supplied to the gas flow path until a detection result of the detection means reaches a predetermined value or more. 9. The fuel cell system according to claim 8, further comprising reaction gas supply means for supplying a reaction gas to the gas flow path in a direction opposite to the scavenging gas.

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