阅读说明：本技术 燃料电池系统 (Fuel cell system ) 是由 松末真明 于 2021-04-23 设计创作，主要内容包括：一种燃料电池系统,包括：堆叠有多个单元电池的堆叠体,所述多个单元电池通过燃料气体与氧化剂气体之间的电化学反应产生电力；第一端板和第二端板,其在所述多个单元电池的堆叠方向被分别堆叠在堆叠体的端面上；循环通道,从堆叠体排出并循环至堆叠体的燃料废气通过该循环通道流动；以及喷射器,其包括流入口、吸入口、喷射口和扩散器,燃料气体从储存该燃料气体的箱流入流入口,从循环通道经吸入口吸入燃料废气,喷射口喷射燃料气体和燃料废气,燃料气体和燃料废气通过扩散器朝向喷射口流动,其中,堆叠体包括歧管,燃料气体和燃料废气通过该歧管沿堆叠方向流动,其中,第一端板具有容纳喷射器的凹部以及使喷射口和歧管彼此连通的连续孔。(A fuel cell system comprising: a stack in which a plurality of unit cells that generate electric power through an electrochemical reaction between a fuel gas and an oxidant gas are stacked; first and second end plates that are stacked on end surfaces of the stack body in a stacking direction of the plurality of unit cells, respectively; a circulation passage through which fuel off-gas discharged from the stack and circulated to the stack flows; and an injector including an inflow port into which a fuel gas flows from a tank storing the fuel gas, a suction port through which a fuel off-gas is sucked from the circulation passage, an injection port through which the fuel gas and the fuel off-gas flow, and a diffuser toward the injection port, wherein the stack includes a manifold through which the fuel gas and the fuel off-gas flow in a stacking direction, wherein the first end plate has a recess accommodating the injector and a continuous hole communicating the injection port and the manifold with each other.)

1. A fuel cell system comprising:

a stack of a plurality of unit cells that generate electric power by an electrochemical reaction between a fuel gas and an oxidant gas;

first and second end plates that are stacked on end surfaces of the stacked body, respectively, in a stacking direction of the plurality of unit cells;

a circulation passage through which the fuel off-gas discharged from the stack is circulated to the stack; and

an injector including an inflow port into which the fuel gas stored in the tank flows, a suction port into which the fuel off-gas is sucked from the circulation passage, an injection port that injects the fuel gas and the fuel off-gas, and a diffuser through which the fuel gas and the fuel off-gas flow toward the injection port,

wherein the stack includes a manifold through which the fuel gas and the fuel off-gas flow in the stacking direction,

wherein the first end plate has a recess that accommodates the ejector and a continuous hole that enables communication between the ejection port and the manifold,

wherein the injector is in contact with an inner face of the concave portion in such a manner that a direction in which the fuel gas and the fuel off-gas in the diffuser flow is along a plate surface of the first end plate and the suction port is exposed.

2. The fuel cell system according to claim 1, further comprising an introduction line that is accommodated in the recess and that introduces the fuel gas and the fuel off-gas injected from the injection port into the continuous hole,

wherein the introduction line changes a direction in which the fuel gas and the fuel off-gas are injected from the injector to the stacking direction.

3. The fuel cell system according to claim 1 or 2,

wherein the first end plate comprises an inflow channel extending along the plate surface from the inflow opening to a side of the first end plate,

wherein the inflow port is connected to the tank through the inflow passage.

4. The fuel cell system according to any one of claims 1 to 3, further comprising a flow member having an opening along a plate surface of the first end plate, the flow member sucking the fuel gas discharged from the tank from the opening and flowing the fuel gas into the inflow port.

Technical Field

The present disclosure relates to a fuel cell system.

Background

A fuel cell includes a plurality of unit cells that generate electric power by a chemical reaction between a fuel gas and an oxidant gas, and a pair of end plates that are stacked on respective end faces of the stacked unit cells in a stacking direction of the unit cells. For example, japanese patent application laid-open No. 2001-143734 (patent document 1) discloses a fuel cell system in which an injector that circulates fuel off-gas to a fuel cell and a recirculation passage of the fuel off-gas from the fuel cell to the injector are provided inside one of end plates.

Disclosure of Invention

The structure disclosed in patent document 1 can reduce the installation space of the fuel cell system. However, when the recirculation passage of the fuel off-gas is provided inside the end plate, the end plate is heated by heat generation of the fuel cell. Therefore, the temperature of the fuel off-gas rises, and the volume of the fuel off-gas expands. This reduces the amount of fuel gas in the fuel off-gas circulated from the injector to the fuel cell, and therefore, the power generation performance may be degraded.

In addition, since low-temperature fuel gas is supplied from the fuel tank to the injector, the fuel off-gas in the injector is cooled by adiabatic expansion of the fuel gas. The fuel off-gas contains water vapor generated by the power generation of the fuel cell. Therefore, when the fuel off-gas is cooled, condensation occurs due to the decrease in the amount of saturated vapor. Liquid water formed by condensation flows from the injector into the passage of the fuel gas in the fuel cell and may block the flow of the fuel gas, resulting in degradation of power generation performance.

Accordingly, it is an object of the present disclosure to provide a small-footprint fuel cell system capable of reducing degradation in power generation performance.

The above object is achieved by a fuel cell system comprising: a stack (stack) of a plurality of unit cells that generate electric power by an electrochemical reaction between a fuel gas and an oxidant gas; first and second end plates that are stacked on end surfaces of the stack body in a stacking direction of the plurality of unit cells, respectively; a circulation passage through which the fuel off-gas discharged from the stack is circulated to the stack; and an injector including an inflow port into which the fuel gas stored in the tank flows, an intake port through which the fuel off-gas is drawn from the circulation passage, an injection port through which the fuel gas and the fuel off-gas are injected, and a diffuser toward which the fuel gas and the fuel off-gas flow through the diffuser, wherein the stack includes a manifold through which the fuel gas and the fuel off-gas flow in a direction of the stack, wherein the first end plate has a recess accommodating the injector and a continuous hole enabling communication between the injection port and the manifold, wherein the injector is in contact with an inner face of the recess in such a manner that a direction of the flow of the fuel gas and the fuel off-gas in the diffuser is along a plate surface of the first end plate and the intake port is exposed.

In the above structure, the injector is in contact with the inner face of the concave portion in such a manner that the direction in which the fuel gas and the fuel off-gas in the diffuser flow is along the plate surface of the first end plate and the suction port is exposed. This structure enables the injector to sufficiently receive heat generated by power generation of the fuel cell stack from the end plate. Therefore, the injector can raise the temperature of the low-temperature fuel gas that has flowed from the tank into the injector and can suppress the fuel off-gas from being cooled. Therefore, condensation is effectively suppressed.

In addition, since the suction port of the ejector is exposed from the recess, the circulation passage is not accommodated in the recess. Therefore, an increase in the temperature of the fuel off-gas flowing through the circulation passage is suppressed, and a decrease in the amount of fuel gas in the fuel off-gas circulating to the fuel cell stack is suppressed.

Therefore, the fuel cell system can reduce degradation of power generation performance and reduce a floor space.

The above-described fuel cell system may include an introduction line that is accommodated in the recess and introduces the fuel gas and the fuel off-gas injected from the injection port into the continuous hole, and that may change a direction in which the fuel gas and the fuel off-gas are injected from the injector to the stacking direction.

In the above fuel cell system, the first end plate may include an inflow passage extending from the inflow port to a side surface of the first end plate along a plate surface, and the inflow port may be connected to the tank through the inflow passage.

The above-described fuel cell system may include a flow member having an opening along a plate surface of the first end plate, the flow member drawing the fuel gas discharged from the tank from the opening and flowing the fuel gas into the inflow port.

Advantageous effects

According to the present disclosure, a small-footprint fuel cell system capable of reducing degradation of its power generation performance can be provided.

Drawings

Fig. 1 is an exploded perspective view showing an exemplary unit cell of a fuel cell;

FIG. 2 is a configuration diagram of an exemplary fuel cell system;

FIG. 3 is a perspective view showing an exemplary structure of an injector;

FIG. 4 illustrates an exemplary manner of housing the injector in a recess of an end plate; and

FIG. 5 illustrates another exemplary manner of receiving an injector in a recess of an end plate.

Detailed Description

[ Structure of the Unit cell 2 ]

Fig. 1 is an exploded perspective view showing an exemplary unit cell 2 of a fuel cell. The fuel cell is used in, for example, a fuel cell vehicle, but the application of the fuel cell is not particularly limited. The fuel cell is a polymer electrolyte type fuel cell and includes a stack in which a plurality of unit cells 2 are stacked.

The unit cells 2 are supplied with a fuel gas (e.g., hydrogen gas) and an oxidant gas (e.g., air), and the unit cells 2 generate electric power through an electrochemical reaction between the fuel gas and the oxidant gas. The fuel gas and the oxidant gas are examples of the reaction gas.

The unit cell 2 includes a MEGA20, a frame 21, a cathode separator 23, and an anode separator 24, which are arranged in the direction in which the unit cells 2 are stacked (the stacking direction of the unit cells 2). The cathode separator 23 and the anode separator 24 are examples of a pair of separators.

The MEGA20 includes a Membrane Electrode Assembly (MEA)200 and a pair of Gas Diffusion Layers (GDLs) 201 and 202 sandwiching the MEA 200 therebetween. Reference numeral P denotes a multi-layered structure of the MEA 200. The MEA 200 includes an electrolyte membrane 200a, and an anode electrode catalyst layer 200b and a cathode electrode catalyst layer 200c that sandwich the electrolyte membrane 200a therebetween.

The electrolyte membrane 200a includes, for example, an ion exchange resin membrane that exhibits good proton conductivity under wet conditions. Examples of such an ion exchange resin membrane include, but are not limited to, fluororesin-based membranes having a sulfonate group as an ion exchange group, such as Nafion (registered trademark).

Each of the anode electrode catalyst layer 200b and the cathode electrode catalyst layer 200c is formed as a porous layer containing a proton-conductive electrolyte and catalyst-supporting conductive particles and having gas diffusibility. For example, the anode electrode catalyst layer 200b and the cathode electrode catalyst layer 200c are formed as dry coating films of a catalyst ink that is a dispersion solution containing platinum-supporting carbon and a proton-conducting electrolyte.

The fuel gas is supplied to the anode catalyst layer 200b through the gas diffusion layer 201, and the oxidant gas is supplied to the cathode catalyst layer 200c through the gas diffusion layer 202. The gas diffusion layers 201 and 202 are formed by stacking hydrophobic microporous layers on a base material such as, but not limited to, carbon paper. The microporous layer comprises a hydrophobic resin such as Polytetrafluoroethylene (PTFE), a conductive material such as carbon black, and the like. The MEA 200 generates electricity by performing an electrochemical reaction using an oxidant gas and a fuel gas.

The frame 21 is made of a resin sheet having a rectangular outer shape, for example. Examples of the material of the frame 21 include polyethylene terephthalate (PET) -based resin, Syndiotactic Polystyrene (SPS) -based resin, and polypropylene (PP) -based resin. The frame 21 has a frame shape and has a rectangular opening 210 in a central portion thereof.

The opening 210 is located at a position corresponding to the position of the MEGA20, and the outer circumferential end of the MEA 200 is bonded to the edge of the opening 210 by an adhesive layer. Thus, the MEA 200 is held by the frame 21.

Through holes 211 to 216 penetrating the frame 21 in the thickness direction of the frame 21 are formed in the end portion of the frame 21. Through holes 211, 215, and 214 are formed in one end portion of the frame 21, and through holes 213, 216, and 212 are formed in the other end portion of the frame 21. The through holes 211 to 216 overlap with the through holes 231 to 236 of the cathode separator 23 and the through holes 241 to 246 of the anode separator 24, respectively.

The through holes 211, 241, and 231 are portions of the anode-side inlet manifold that are supply ports of the fuel gas, and the fuel gas flows through the through holes 211, 241, and 231 in the stacking direction of the unit cells 2. The through-holes 212, 242, and 232 are portions of the anode-side outlet manifold that serve as exhaust ports for the fuel gas, and the fuel off-gas flows through the through-holes 212, 242, and 232 in the stacking direction of the unit cells 2.

The through holes 213, 243, and 233 are portions of the cathode-side inlet manifold that are supply ports of the oxidant gas, and the oxidant gas flows through the through holes 213, 243, and 233 in the stacking direction of the unit cells 2. The through holes 214, 244, and 234 are portions of the cathode-side outlet manifold that serve as exhaust ports for the oxidant gas, and the oxidant off-gas flows through the through holes 214, 244, and 234 in the stacking direction of the unit cells 2.

The through-holes 215, 245, and 235 are portions of the cooling water inlet manifold that are supply ports of cooling water that cools the unit cells 2, and the cooling water flows through the through-holes 215, 245, and 235 in the stacking direction of the unit cells 2. The through-holes 216, 246, and 236 are portions of the cooling water outlet manifold that serve as discharge ports for the cooling water, and the cooling water flows through the through-holes 216, 246, and 236 in the stacking direction of the unit cells 2.

Each of the cathode separator 23 and the anode separator 24 is made of metal such as SUS or titanium, formed into a sheet, and has a rectangular outer shape. The cathode separator 23 and the anode separator 24 are bonded to each other using, for example, laser welding, in which the plate surface of the cathode separator 23 and the plate surface of the anode separator 24 are opposed to each other. An anode separator 24 is disposed on the anode side of the MEGA20, and a cathode separator 23 is disposed on the cathode side of the MEGA20 of another unit cell 2 adjacent to the unit cell 2.

The anode separator 24 is bonded to the frame 21 by an adhesive. Thus, the frame 21 is fixed to the anode separator 24.

The anode separator 24 has through-holes 241 to 246 penetrating the anode separator 24 in the thickness direction of the anode separator 24 and an anode channel portion 240 having a wave plate shape. Through-holes 241, 245, and 244 are formed in one end portion of the anode separator 24, and through-holes 243, 246, and 242 are formed in the other end portion of the anode separator 24.

Groove-shaped fuel gas channels through which the fuel gas flows are formed on a first surface of the anode channel portion 240 near the MEGA 20. The fuel gas channel is opposed to the gas diffusion layer 201, and fuel gas is supplied from the fuel gas channel to the gas diffusion layer 201. In addition, groove-shaped cooling water channels through which cooling water flows are formed on a second surface of the anode channel portion 240 adjacent to the cathode separator 23.

The anode channel part 240 is formed by bending with a press die, for example. The fuel gas channel and the cooling water channel may be formed in a straight line shape or may be formed in a zigzag line shape.

The cathode separator 23 has through-holes 231 to 236 penetrating the cathode separator 23 in the thickness direction of the cathode separator 23 and a cathode channel portion 230 having a wave plate shape. Through-holes 231, 235, and 234 are formed in one end portion of the cathode separator 23, and through-holes 233, 236, and 232 are formed in the other end portion of the cathode separator 23.

A groove-shaped cooling water passage through which the cooling medium flows is formed on a first surface of the cathode passage portion 230 adjacent to the anode separator 24. In addition, groove-shaped oxidant gas channels, through which the oxidant gas flows, are formed on the second surface of the cathode channel portion 230, which is close to the MEGA20 of another unit cell 2 adjacent to the unit cell 2. The oxidant gas channel is opposed to the gas diffusion layer 202 of the MEGA20 of the adjacent unit cell 2, and the oxidant gas is supplied from the oxidant gas channel to the diffusion layer 202.

The cathode channel part 230 is formed by bending with a press die, for example. The cooling medium passage and the fuel gas passage may be formed in a straight line shape or may be formed in a zigzag line shape, for example. The material of the cathode separator 23 and the anode separator 24 is not limited to metal, and may be formed of a carbon molded article.

[ configuration of the Fuel cell System 9 ]

Fig. 2 is a configuration diagram of an exemplary fuel cell system 9. The fuel cell system 9 is mounted in, for example, a fuel cell vehicle, not shown, and serves as a power source of an electric motor of the fuel cell vehicle.

The fuel cell system 9 includes the fuel cell stack 1, the injector 4, the tank 50, an Injector (INJ)51, a gas-liquid separator 52, a discharge valve 53, and an Air Compressor (ACP) 54. In addition, the fuel cell system 9 includes a fuel line L1, a fuel supply line L2, a fuel exhaust line L3, a fuel recirculation line L4, an exhaust and drain line L5, an air supply line L6, and an air exhaust line L7.

The fuel cell stack 1 includes a stack 2S in which a plurality of unit cells 2 are stacked, and a pair of end plates 30 and 31 stacked on the respective end surfaces 2St and 2Sb in a stacking direction Ds of the stack 2S. Each of the end plates 30 and 31 is a metal plate having a substantially rectangular parallelepiped shape and formed of, for example, SUS. The end plate 30 is an example of a first end plate, and the end plate 31 is an example of a second end plate.

The stack 2S includes an anode-side inlet manifold 250 through which the fuel gas to be supplied to each unit cell 2 flows, and an anode-side outlet manifold 260 through which the fuel gas (i.e., the fuel off-gas) discharged from each unit cell 2 flows. Although illustration is omitted, the stack 2S also includes a cathode-side inlet manifold through which the oxidant gas to be supplied to each unit cell 2 flows, and a cathode-side outlet manifold through which the oxidant gas (i.e., the oxidant off-gas) discharged from each unit cell 2 flows.

The fuel cell stack 1 supplies electric power generated by an electrochemical reaction between the fuel gas and the oxidant gas to a motor or the like.

The air compressor 54 takes in air as an oxidant gas from the outside of, for example, a fuel cell vehicle and compresses the oxidant gas. The air compressor 54 pumps the oxidant gas to the cathode side inlet manifold of the fuel cell stack 1 through the air supply line L6. The oxidant gas is distributed to each unit cell 2 from the cathode-side inlet manifold, and then used for power generation.

The tank 50 stores, for example, compressed hydrogen gas as fuel gas. Fuel gas flows from tank 50 into injector 51 through fuel line L1. The injector 51 injects the fuel gas in accordance with the electric power required to be generated by the fuel cell stack 1. The fuel gas flows from the injector 51 into the injector 4 through the fuel supply line L2.

The injector 4 mixes the fuel gas from the injector 51 with the fuel off-gas discharged from the fuel cell stack 1, and injects the mixed gas to the anode-side inlet manifold 250 of the stack 2S. The ejector 4 is accommodated in a recess 300 formed on the plate surface of the end plate 30. The recess 300 is a hole having a longitudinal direction parallel to the side of the rectangular end plate 30. The ejector 4 is in contact with the inner face of the recess 300.

Therefore, the injector 4 receives heat generated by the power generation of the fuel cell stack 1 and raises the temperature. This enables the injector 4 to heat the low-temperature fuel gas from the tank 50.

The fuel gas injected from the injector 4 flows through the anode-side inlet manifold 250 (see the arrow Din) through the continuous hole 301 formed on the bottom of the concave portion 300, is distributed from the anode-side inlet manifold 250 to each unit cell 2, and is then used for power generation. The anode-side inlet manifold 250 is an example of a manifold through which the fuel gas and the fuel off-gas flow in the stacking direction Ds.

The fuel off-gas flows from each unit cell 2 into the anode-side outlet manifold 260. The fuel off-gas flows from the anode-side outlet manifold 260 through the discharge hole 310 of the end plate 31, and is discharged to the fuel discharge line L3 (see arrow Dout). The discharge holes 310 are formed in the thickness direction of the end plate 31.

The gas-liquid separator 52 is connected to the fuel discharge line L3, the fuel recirculation line L4, and the drain and water discharge line L5. The gas-liquid separator 52 separates liquid water from the fuel off-gas flowing into the gas-liquid separator 52 through the fuel discharge line L3 and stores the liquid water in the bottom thereof. The discharge valve 53 is connected to a discharge and drain line L5. When the discharge valve 53 is opened, the liquid water stored in the gas-liquid separator 52 flows through the discharge and drain line L5 and is discharged to the outside.

The discharge and drain line L5 is connected to the air discharge line L7 on the downstream side of the discharge valve 53. The air exhaust line L7 is connected to a cathode-side outlet manifold through which the oxidant off-gas discharged from each unit cell 2 flows. The oxidant off-gas flows into the air exhaust line L7 from the cathode-side outlet manifold, and is discharged to the outside from the discharge and drain line L5.

The fuel offgas flows from the gas-liquid separator 52 into the injector 4 through the fuel recirculation line L4. The injector 4 mixes the fuel gas supplied from the tank 50 with the fuel off-gas, and injects the mixed gas to the anode-side inlet manifold 250 through the continuous hole 301. As a result, the fuel off-gas is circulated to the fuel stack 1. The fuel recirculation line L4 is an example of a circulation passage through which the fuel off-gas discharged from the stack 2S is circulated to the stack 2S through the fuel recirculation line L4.

[ Structure of injector 4 ]

Fig. 3 is a perspective view showing an exemplary structure of the ejector 4. Fig. 3 shows not only the ejector 4, but also the end plate 30 having a recess 300 accommodating the ejector 4.

As an example, the injector 4 has a substantially cylindrical gas passage in its interior, and is enclosed in a housing 40 (see a broken line) having a substantially rectangular parallelepiped shape. The material of the housing 40 is preferably a material having a high thermal conductivity. The recess 300 is formed to have a space of a substantially rectangular parallelepiped shape so as to correspond to the outer shape of the case 40. The injector 4 does not have to be enclosed in the housing 40, and may be directly accommodated in the recess 300.

The ejector 4 includes a substantially conical nozzle 41, a mixing chamber 42, a substantially cylindrical suction port 43, and a diffuser 44. The nozzle 41 includes an inlet 410 for fuel gas, a passage 411, and an outlet 412. The inlet 410 of the nozzle 41 is connected to the inflow channel 302, and the inflow channel 302 linearly extends from the inner face 300a of one end of the recess 300 to the side face 30a of the end plate 30. The shape of the inflow channel 302 is not limited to a linear shape and may be a curved shape.

The inlet 302a of the inflow channel 302 is open toward the side 30a and is connected to the outlet of the fuel supply line L2. That is, the inlet 410 of the nozzle 41 is connected to the tank 50 through the inflow channel 302. Fuel gas passes from fuel supply line L2 through inflow channel 302, flows from inlet 410 of nozzle 41 into channel 411, and is then injected from outlet 412 into mixing chamber 42 as indicated by arrow Da. Therefore, the injector 4 can suck the fuel gas from the side face 30a of the end plate 30. The inlet 410 of the nozzle 41 is an example of an inflow port into which the fuel gas stored in the tank 50 flows.

A suction port 43 communicating with the mixing chamber 42 is provided on the outer surface of the housing 40. The suction port 43 does not contact the inner face of the concave portion 300 and is exposed from the concave portion 300. The suction port 43 is connected to the outlet of the fuel recirculation line L4. After flowing through the fuel recirculation line L4, the fuel off-gas is drawn from the suction port 43 and then flows into the mixing chamber 42 as indicated by arrow Db.

The fuel gas from the nozzle 41 and the fuel off-gas from the suction port 43 are mixed in the mixing chamber 42. The mixture of the fuel gas and the fuel off-gas flows through the injection passages 441 in the diffuser 44, and is then ejected from the injection ports 440 as indicated by reference numeral Dc. The direction in which the injection channel 441 extends is the longitudinal direction of the injector 4. The fuel gas and the fuel off-gas injected from the injection port 440 flow from the continuous hole 301 into the anode-side inlet manifold 250 through a fuel introduction line described later.

When the ejector 4 is accommodated in the recess 300, at least a portion of each of the faces other than the face 40a on which the suction port 43 is arranged and the face 40b on which the ejection port 440 is arranged, among the faces of the housing 40 having a substantially rectangular parallelepiped shape, is in contact with a corresponding one of the inner faces 300a to 300d of the recess 300. Here, the inner face 300d is a bottom face of the recess 300, and the inner faces 300b and 300c are a pair of side faces of the recess 300. The inner face 300e is an end face opposite to the inner face 300a on which the inflow channel 302 is provided. Since the inner face 300e is located on the fuel introduction line 6 side, the inner face 300e does not contact the injector 4.

The injector 4 is accommodated in the recess 300 in the following manner: this is such that the direction Df of the fuel gas and the fuel off-gas flow in the diffuser 44 (hereinafter described as "flow direction Df") is along the plate surface Ps of the end plate 30.

[ exemplary manner of accommodating the ejector 4 ]

Fig. 4 shows an exemplary manner of accommodating the injector 4 in the recess 300 of the end plate 30. In fig. 4, the same reference numerals are attached to the same components as those in fig. 3, and the description thereof is omitted.

Reference numeral G1a denotes a plan view when the plate surface Ps of the end plate 30 is viewed from the front. Reference numeral G1b denotes a sectional view taken along line a-a in the plan view indicated by reference numeral G1 a. Reference numeral G1c denotes a sectional view taken along line B-B in the plan view indicated by reference numeral G1 a.

The recess 300 accommodates the injector 4 and the fuel introduction line 6. The fuel introduction line 6 is accommodated near the face 40b of the injector 4. The fuel introduction line 6 is an example of an introduction line, and introduces the fuel gas and the fuel off-gas injected from the injection port 440 of the injector 4 into the continuous hole 301. An inlet of the fuel introduction line 6 is connected to the injection port 440, and an outlet of the fuel introduction line 6 is connected to the continuous hole 301.

Thus, the fuel introduction line 6 is bent in such a way that the orientation of the inlet is substantially perpendicular to the orientation of the outlet. This structure enables the fuel introduction line 6 to change the direction in which the fuel gas and the fuel off-gas are injected from the injector 4 to the stacking direction Ds.

Therefore, as in the present embodiment, even in the case where the flow direction Df in the injector 4 is substantially perpendicular to the stacking direction Ds of the stack 2S, the fuel gas and the fuel off-gas can be guided from the injector 4 to the anode-side inlet manifold 250 as indicated by the arrow Di. Instead of the fuel introduction line 6, a passage similar to the fuel introduction line 6 may be provided inside the end plate 30.

The injector 4 is in contact with the inner face of the concave portion 300 in such a manner that the flow direction Df of the fuel gas and the fuel off-gas in the diffuser 44 is along the plate surface Ps of the end plate 30 and the suction port 43 is exposed. This structure enables the injector 4 to sufficiently receive heat generated by power generation of the fuel cell stack 1 from the end plate 30. Therefore, the injector 4 can raise the temperature of the low-temperature fuel gas flowing from the tank 50 into the injector 4 and suppress the fuel off-gas from being cooled. Therefore, condensation is effectively suppressed.

In contrast, when the injector 4 is housed in the recess 300 in such a manner that the flow direction Df intersects at right angles with the plate surface Ps of the end plate 30, that is, the flow direction Df is substantially parallel to the stacking direction Ds of the stack body 2S as in patent document 1, the length of the injector 4 in the longitudinal direction, that is, the length of the injector 4 in the flow direction Df as the direction in which the injection channel 441 extends, is limited by the thickness TH of the end plate 30. In this case, the ejector 4 may not receive sufficient heat from the end plate 30. Therefore, condensation cannot be effectively suppressed.

In addition, in the above case, when the thickness TH of the end plate 30 is increased, the restriction on the length of the injector 4 in the longitudinal direction is reduced. However, as the thickness TH of the end plate 30 increases, the size of the fuel cell stack 1 increases and a large installation space becomes necessary.

In addition, in the present embodiment, since the suction port 43 of the injector 4 is exposed from the recess 300, the fuel recirculation line L4 is not accommodated in the recess 300. Thus, the temperature increase of the fuel off-gas flowing through the fuel recirculation line L4 is suppressed, and the decrease in the amount of fuel gas in the fuel off-gas circulating to the fuel cell stack 1 is suppressed.

Therefore, the fuel cell system 9 suppresses degradation of the power generation performance of the fuel cell stack 1 and reduces the footprint thereof.

[ Another exemplary manner of accommodating the ejector 4 ]

Fig. 5 shows another exemplary manner of accommodating the injector 4 in the recess 300' of the end plate 30. In fig. 5, the same reference numerals are attached to the same components as those in fig. 3 and 4, and the description thereof is omitted.

Reference numeral G2a denotes a plan view when the plate surface Ps of the end plate 3 is viewed from the front. Reference numeral G2b denotes a sectional view taken along a line a '-a' in the plan view indicated by reference numeral G2 a. Reference numeral G2c denotes a sectional view taken along a line B '-B' in the plan view indicated by reference numeral G2 a.

The recess 300' in this example accommodates the flow member 7 in addition to the injector 4 and the fuel introduction line 6. Therefore, the length of the recess 300' in the longitudinal direction is longer than the length of the recess 300 in the longitudinal direction. The flow member 7 has a substantially rectangular parallelepiped shape, and is adjacent to the end of the injector 4 opposite to the fuel introduction line 6.

The flow member 7 has an opening 70 along the plate surface Ps of the end plate 30 and a passage 71 bent at a substantially right angle from the opening 70 toward the inlet 410 of the nozzle 41. As an example, the opening 70 has a circular shape and is connected to the fuel supply line L2. The outlet of the channel 71 is connected to the inlet 410 of the nozzle 41. Therefore, the fuel gas from the tank 50 flows from the opening 70 into the passage 71 as indicated by the arrow Dt and then flows into the inlet 410 of the nozzle 41 through the passage 71.

Therefore, even if the inlet 410 of the nozzle 41 is not along the plate surface Ps of the end plate 30, the injector 4 can suck the fuel gas from the plate surface Ps side.

Although some embodiments of the present invention have been described in detail, the present invention is not limited to these specific embodiments, but may be changed or modified within the scope of the present invention as claimed.