JP2017147094A - Fuel cell - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fuel cell which is improved in power generation performance without being limited in size.SOLUTION: A fuel cell comprises: a first supplying part which is cooled by an oxidant gas and provided with a first flow path for supplying the oxidant gas; a second supplying part provided with a second flow path for supplying a fuel gas; a first power-generation part provided on an upstream side of the first flow path so as to be located between the first supplying part and the second supplying part, and generating a power by the oxidant gas and the fuel gas; a second power-generation part provided on a downstream side of the first flow path so as to be located between the first supplying part and the second supplying part, and generating a power by the oxidant gas and the fuel gas; and an interruption part for interrupting liquid water. The first power-generation part includes a first electrolyte membrane having proton conductivity in a water-retaining condition. The second power-generation part includes a second electrolyte membrane having proton conductivity in a high-temperature condition of 80°C or higher. The interruption part separates at least a region on a side of the second supplying part from the first electrolyte membrane from a region on a side of the second supplying part from the second electrolyte membrane between the first and second supplying parts.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a fuel cell.

  As a new vehicle different from a gasoline vehicle, a fuel cell vehicle (FCV) equipped with a fuel cell attracts attention. The fuel cell mounted on the FCV drives the motor by generating electricity by chemically reacting hydrogen of fuel and oxygen in the air.

  As a cooling method of the fuel cell, a water cooling type in which cooling water is circulated and an air cooling type in which air supplied for power generation is used for cooling (for example, see Patent Document 1) are known. Air-cooled fuel cells have the advantage that the cooling system is smaller than water-cooled fuel cells.

JP 2013-256234 A

  However, since the thermal conductivity of air is about 1/25 of the thermal conductivity of cooling water, the air-cooled fuel cell has a problem that the cooling efficiency is lower than that of the water-cooled type. For this reason, when the output of the air-cooled fuel cell is increased, the temperature in the fuel cell rises and the temperature gradient along the air flow path becomes significant.

  Therefore, even if the polymer electrolyte membrane in the fuel cell is sufficiently cooled on the upstream side of the flow path, the cooling is insufficient on the downstream side of the flow path. For this reason, since the temperature of the polymer electrolyte membrane locally rises and dries, the polymer electrolyte membrane loses proton conductivity and the power generation performance of the fuel cell decreases.

  In contrast, for example, by reducing the size of the fuel cell in the flow direction of oxygen, local drying is improved, and further, the size in the width direction perpendicular to the flow direction is increased and the number of stacked fuel cells The power generation performance can be secured by increasing the power consumption. However, in this case, since the size of the fuel cell is limited, for example, there is a problem that the design of the FCV or the like on which the fuel cell is mounted is also limited. This problem is not limited to the fuel cell mounted on the FCV, but also exists for fuel cells for other uses.

  Accordingly, the present invention has been made in view of the above problems, and an object thereof is to provide a fuel cell with improved power generation performance without being limited in size.

  The fuel cell described in the present specification is a fuel cell that is cooled by supplying an oxidant gas, and includes a first supply unit provided with a first flow path for supplying the oxidant gas, and a fuel gas. A second supply section provided with a second flow path for supplying the first flow path, and an upstream side of the first flow path so as to be sandwiched between the first supply section and the second supply section. It is sandwiched between a first power generation unit that generates electric power by a reaction between the oxidant gas supplied from the flow channel and the fuel gas supplied from the second flow channel, and the first supply unit and the second supply unit. A second power generation unit that is provided on the downstream side of the first flow path and generates power by a reaction between the oxidant gas supplied from the first flow path and the fuel gas supplied from the second flow path; A blocking section for blocking the flow of liquid water generated by the power generation of the first power generation section and the second power generation section; The first power generation unit has a first electrolyte membrane having proton conductivity in a water-containing state, and the second power generation unit has a second electrolyte membrane having proton conductivity in a high temperature state of 80 ° C. or higher. The blocking unit includes at least a region on the second supply unit side from the first electrolyte membrane between the first supply unit and the second supply unit, and the second supply unit from the second electrolyte membrane. It is provided so as to be separated from the region on the side.

  According to the present invention, the power generation performance of a fuel cell can be improved without being limited in size.

It is a block diagram which shows an example of an air-cooling type fuel cell system. It is a figure which shows the comparative example of arrangement | positioning of a membrane electrode assembly. It is a figure which shows the change of the temperature distribution with respect to the position along a cathode flow path, and the electric power generation amount. It is a figure which shows the Example of arrangement | positioning of a membrane electrode assembly. It is a figure which shows an example of the change of the proton conductivity with respect to the temperature change of an electrolyte membrane. It is a figure which shows an example of the relationship between the position in the flow path direction of temperature and air. It is a perspective view of an example of a fuel cell. It is a disassembled perspective view of an example of a fuel cell. It is sectional drawing which shows an example of a fuel cell. It is sectional drawing which shows the other example of a fuel cell. It is a disassembled perspective view of the other example of a fuel cell. It is sectional drawing which shows the other example of a fuel cell.

  FIG. 1 is a configuration diagram showing an example of an air-cooled fuel cell system. The fuel cell 9 is supplied with hydrogen gas, which is an example of fuel gas, and air, which is an example of oxidant gas. The fuel cell 9 is cooled by supplied air and generates power by a chemical reaction between hydrogen and oxygen in the air.

  The electric power obtained by the power generation of the fuel cell 9 is output to the load 7 via an electric cable or the like. An example of the load 7 is a motor that drives a vehicle.

  The fuel cell 9 discharges hydrogen gas used for power generation and oxygen containing water vapor generated by power generation to the outside of the fuel cell 9.

  The fuel cell 9 is configured by stacking a plurality of fuel cells. Each fuel cell is provided with a membrane electrode assembly (MEA) that generates power and a cathode flow path through which air supplied to the cathode side of the MEA flows.

  FIG. 2 shows a comparative example of the arrangement of MEAs. Each fuel cell is provided with one MEA 20.

  The MEA 20 includes an anode electrode, a cathode electrode, and an electrolyte membrane sandwiched between the anode electrode and the cathode electrode. As the electrolyte membrane, one having proton conductivity in a water-containing state (hereinafter referred to as “hydrated electrolyte membrane”) is used. Examples of the aqueous electrolyte membrane include polymer electrolyte membranes having a sulfonic acid group such as Nafion (registered trademark) (herfluorosulfonic acid membrane, hydrocarbon membrane, etc.).

  Further, the cathode channel is provided along the direction indicated by the arrow. The root of the arrow is on the upstream side of the cathode flow path, and the arrow tip of the arrow is on the downstream side of the cathode flow path. As the air flows from the upstream side to the downstream side in the cathode flow path, the MEA 20 is cooled while being supplied with oxygen in the air. The symbol L is the position in the direction of the cathode flow path when the upstream end of the MEA 20 is set to zero.

  In the air-cooled fuel cell, when the output is increased, the temperature in the fuel cell rises and the temperature gradient along the cathode flow path becomes remarkable.

  FIG. 3 shows changes in temperature distribution and power generation amount with respect to position L along the cathode flow path. In FIG. 3, the power generation amount is indicated by the hatching density in the frame, as indicated by reference numeral G <b> 3. The darker the hatching, the lower the power generation amount.

  Since the air flowing through the cathode flow channel takes heat from the MEA 20 as a refrigerant, the temperature rises from the entrance to the exit of the cathode flow channel. For this reason, the temperature of the MEA 20 is also low in the region upstream of the cathode flow channel, but is high in the region downstream of the cathode flow channel.

  Since the aqueous electrolyte membrane in the MEA 20 is dried when the temperature rises, it loses proton conductivity. For this reason, the power generation amount becomes lower toward the downstream side of the cathode channel. In order not to lose the proton conductivity of the aqueous electrolyte membrane, the temperature is required to be, for example, 80 (° C.) or less.

  In this example, since the temperature exceeds 80 (° C.) in the range of position L> 22 (mm), the size of the fuel cell in the cathode flow path direction is limited to less than 22 (mm). Furthermore, in order to compensate for the amount of power generation that decreases due to the reduction in the size in the cathode flow path direction, it is required to increase the size in the width direction of the fuel cells and increase the number of stacked fuel cells. However, in this case, since the size of the fuel cell 9 is limited, for example, the design of a vehicle on which the fuel cell is mounted is also limited.

  Therefore, in the fuel cell 9 of the embodiment, the MEA including the water-containing electrolyte membrane is provided on the upstream side of the cathode flow path, and has proton conductivity in the high temperature state of 80 ° C. or higher on the downstream side of the cathode flow path. An electrolyte membrane (hereinafter referred to as “anhydrous electrolyte membrane”) is provided.

  FIG. 4 shows an example of an arrangement of MEAs. In the embodiment, two types of MEAs 21 and 22 are provided in one fuel cell 9 so as to be adjacent to each other in the cathode flow path direction.

  MEA 21 and 22 are different in the type of electrolyte membrane. One MEA 21 includes a water-containing electrolyte membrane, and the other MEA 22 includes an anhydrous electrolyte membrane. Examples of the anhydrous electrolyte membrane include an ionic liquid impregnated membrane and a PBI-phosphate membrane. The water-containing electrolyte membrane and the anhydrous electrolyte membrane show different proton conductivity with respect to temperature change.

  FIG. 5 shows an example of changes in proton conductivity (S / cm) with respect to changes in temperature of the electrolyte membrane. In FIG. 5, a graph indicated by a symbol G <b> 1 indicates the temperature characteristics of proton conductivity of the water-containing electrolyte membrane, and a graph indicated by a symbol G <b> 2 indicates the temperature characteristics of proton conductivity of the anhydrous electrolyte membrane. The temperature at the intersection point p between the graph of the symbol G1 and the graph of the symbol G2 is 80 (° C.).

  The water-containing electrolyte membrane exhibits high proton conductivity when the temperature is lower than 80 (° C.), but when the temperature is 80 (° C.) or higher, the water is lost due to drying at a high temperature. Decreases. That is, the hydrated electrolyte membrane has high proton conductivity in a water-containing state.

  On the other hand, the anhydrous electrolyte membrane increases in proton conductivity as the temperature rises. Therefore, when the temperature is less than 80 (° C.), it exhibits low proton conductivity, but when the temperature is 80 (° C.) or more. Show high proton conductivity. That is, the anhydrous electrolyte membrane has high proton conductivity at a high temperature of 80 ° C. or higher.

  Thus, the water-containing electrolyte membrane shows high proton conductivity at a low temperature range, and the anhydrous electrolyte membrane shows high proton conductivity at a high temperature range. For this reason, in the embodiment, by utilizing the characteristic of the proton conductivity opposite to that, the MEA 21 including the aqueous electrolyte membrane is disposed in the region A1 on the upstream side of the cathode flow path as shown in FIG. The MEA 22 including the electrolyte membrane is disposed in a region A2 on the downstream side of the cathode channel.

  FIG. 6 shows an example of the relationship between the temperature and the position L in the air flow path direction. The temperature of the region A1 where the MEA 21 is disposed is less than 80 (° C.), and the temperature of the region A2 where the MEA 22 is disposed is 80 (° C.) or more. For this reason, the MEA 21 exhibits proton conductivity in the low temperature region A1, and the MEA 22 exhibits proton conductivity in the high temperature region A2. Therefore, the fuel cell 9 of the embodiment can increase the amount of power generation as compared with the comparative example shown in FIG.

  However, in the anhydrous electrolyte membrane, the electrolyte easily flows out in an environment where liquid water is present. Therefore, in the fuel cell 9, the liquid water generated by the power generation in the MEA 21 of the hydrated electrolyte membrane flows into the MEA 22 of the anhydrous electrolyte membrane. It has a structure for preventing this. The configuration of the fuel cell 9 will be described below.

  FIG. 7 is a perspective view of an example of the fuel cell 9, and FIG. 8 is an exploded perspective view thereof. 7 and 8, the right direction on the paper surface is the positive direction of the x axis, the oblique back direction of the paper surface is the positive direction of the y axis, and the upward direction of the paper surface is the positive direction of the z axis. Thus, the x-axis direction corresponds to the width direction of the fuel cell 9, the y-axis direction corresponds to the depth direction of the fuel cell 9, and the z-axis direction corresponds to the stacking direction of the fuel cells 5. The definition of the coordinate system is the same in the following drawings.

  The fuel cell 9 is a polymer electrolyte fuel cell that generates electric power by receiving supply of air as an oxidant gas and hydrogen gas as a fuel gas, and has a stacked structure in which a plurality of fuel cells 5 are stacked. . The fuel cell 5 includes a cathode side separator 12, a MEGA (Membrane Electrode Gas diffusion layer Assembly) housing frame 2, and an anode side separator 3. The MEGA housing frame 2 houses gas diffusion layers (GDL) 41 to 44 and MEAs 21 and 22 (that is, MEGA), and is sandwiched between the cathode-side separator 12 and the anode-side separator 3 that are plate-like members. ing.

  The cathode-side separator 12 is formed of a conductive material such as carbon or stainless steel, and has an uneven shape in the thickness direction (z-axis direction) formed by, for example, bending with a press die. The cathode-side separator 12 is an example of a first supply unit, and is provided with a plurality of parallel cathode channels 120 and 121 that are formed in an uneven shape in the thickness direction. Each of the cathode channels 120 and 121 is an example of a first channel for supplying air (oxygen) to the MEAs 21 and 22, and is provided on both surfaces of the cathode separator 12 in parallel with each other along the y-axis direction. ing.

  One surface of the cathode-side separator 12 faces one surface of the MEGA housing frame 2, and the other surface of the cathode-side separator 12 faces one surface of the anode-side separator 3. The cathode channel 120 provided on the opposing surface of the MEGA housing frame 2 guides the supplied air to the MEAs 21 and 22, as indicated by arrows, and converts the air used for power generation by the MEAs 21 and 22 by power generation. It is discharged together with the generated water vapor. Further, the cathode channel 120 and the cathode channel 121 provided on the facing surface of the anode-side separator 3 cool the entire fuel cell 9 by passing air from the air supply port to the air discharge port.

  Insulating seal portions 10 and 11 are provided at both ends of the cathode separator 12 in the x-axis direction. The insulating seal portions 10 and 11 are gas sealing insulating members. The insulating seal portions 10 and 11 insulate the cathode separator 12 from the outside of the fuel cell 9 and ensure airtightness.

  The insulating seal portion 10 at one end is provided with a through hole 100 penetrating in the stacking direction of the fuel cells 5. The through hole 100 has a rectangular opening surface and functions as a part of a supply manifold 90 that supplies hydrogen gas to the fuel cell 9. The insulating seal portion 11 at the other end is provided with through holes 101 a and 101 b that penetrate in the stacking direction of the fuel cells 5. The through holes 101a and 101b are provided adjacent to each other in the y-axis direction, and function as part of discharge manifolds 91a and 91b for discharging the hydrogen gas used for power generation from the fuel cell 9, respectively.

  The MEGA housing frame 2 has a pair of through-holes 200, 201a, 201b formed at both ends in the y-axis direction, a housing hole 241 that houses the GDLs 41, 43, and the MEA 21, and a housing hole that houses the GDLs 42, 44, and the MEA 22. 242.

  The accommodation holes 241 and 242 are rectangular through holes provided side by side in the y direction, and are separated from each other via a partition wall 213 extending in the x axis direction. In FIG. 8, the MEAs 21 and 22 are shown housed in the housing holes 241 and 242, respectively.

  The GDL 41 is stacked on the cathode electrode of the MEA 21 in the accommodation hole 241, and is sandwiched between the MEA 21 and the cathode-side separator 12 in the accommodation hole 241. The GDL 42 is stacked on the cathode electrode of the MEA 22 in the accommodation hole 242, and is sandwiched between the MEA 22 and the cathode-side separator 12 in the accommodation hole 242.

  The GDL 43 is stacked under the anode electrode of the MEA 21 in the accommodation hole 241, and is sandwiched between the MEA 21 and the anode side separator 3 in the accommodation hole 241. The GDL 44 is stacked under the anode electrode of the MEA 22 in the accommodation hole 242 and is sandwiched between the MEA 22 and the anode side separator 3 in the accommodation hole 242.

  The through hole 200 has a rectangular opening surface and functions as a part of a supply manifold 90 that supplies hydrogen gas to the fuel cell 9, and the through holes 201a and 201b are provided adjacent to each other in the y-axis direction. The fuel cell 9 functions as a part of discharge manifolds 91a and 91b for discharging hydrogen gas used for power generation.

  The MEGA housing frame 2 is formed of resin, for example, and the MEAs 21 and 22 arranged in parallel connection for different power generation characteristics are sealed with respect to other configurations and integrated into the housing holes 241 and 242. To do. For this reason, since the members for mutual fastening and sealing are shared between the MEAs 21 and 22, the fuel cell 9 is downsized.

  The anode separator 3 is an example of a second supply unit, and is formed of a conductive material such as carbon or stainless steel, and faces the through holes 30, 31a, 31b provided at both ends in the x-axis direction and the MEAs 21, 22. And an anode channel 32 formed on the surface to be formed. The anode flow path 32 is an example of a second flow path for supplying hydrogen gas to the MEAs 21 and 22, and connects between the through hole 30 and the through hole 31a and between the through hole 30 and the through hole 31b.

  The anode flow path 32 is a groove formed by, for example, pressing, and as an example, a plurality of anode flow paths 32 are provided so as to go from the through hole 30 on the inlet side to the through holes 31a and 31b on the outlet side. The anode flow path 32 guides the hydrogen gas supplied from the through hole 30 to the MEAs 21 and 22, and the hydrogen gas used for power generation by the MEAs 21 and 22 and liquid water generated by the power generation to the through holes 31a and 31b, respectively. Lead.

  The through hole 30 at one end has a rectangular opening surface and overlaps the through hole 200 of the MEGA housing frame 2 and the through hole 100 of the insulating seal portion 10. Thereby, the stacked through holes 30, 100, 200 for all the fuel cells 5 constitute a supply manifold 90 for supplying hydrogen gas from the outside of the fuel cell 9, as shown in FIG.

  The through holes 31a and 31b at the other end have a rectangular opening and are provided adjacent to each other in the y-axis direction. The through hole 31 a overlaps with the through hole 201 a of the MEGA housing frame 2 and the through hole 101 a of the insulating seal portion 11. Therefore, as shown in FIG. 1, the through holes 31 a, 101 a, and 201 a are stacked by the number of stacked fuel cells 5 to form a discharge manifold 91 a that discharges hydrogen gas to the outside of the fuel cell 9. To do.

  The through hole 31 b overlaps the through hole 201 b of the MEGA housing frame 2 and the through hole 101 b of the insulating seal portion 11. Therefore, as shown in FIG. 7, the through holes 31 b, 101 b, and 201 b constitute the discharge manifold 91 b that discharges hydrogen gas to the outside of the fuel cell 9 by being stacked by the number of stacked fuel cells 5. To do.

  The supply manifold 90 and the discharge manifolds 91 a and 91 b are through holes provided along the stacking direction of the fuel cells 5. Hydrogen gas is introduced into the supply manifold 90 from the hydrogen supply port 92 at the bottom of the fuel cell 9, and flows as indicated by reference numeral D1. The hydrogen supply port 92 corresponds to, for example, the lowermost through hole 100 of the stack of fuel cells 9.

  A part of the hydrogen gas introduced into the supply manifold 90 is introduced into each anode-side separator 3 in the stack, is discharged to the discharge manifolds 91a and 91b through the anode flow path 32, and is shown in FIG. The hydrogen is discharged to the outside through the hydrogen discharge ports 93a and 93b at the bottom of the battery 9. The hydrogen discharge ports 93a and 93b correspond to the lowermost through holes 101a and 101b of the stacked body of the fuel cell 9, for example.

  A part of the liquid water generated by the chemical reaction between hydrogen gas and oxygen is also discharged to the discharge manifolds 91a and 91b through the anode channel 32. More specifically, the liquid water generated by the MEA 21 is discharged from the discharge manifold 91a, and the liquid water generated by the MEA 22 is discharged from the discharge manifold 91b.

  In this way, since the discharge manifolds 91a and 91b of the MEAs 21 and 22 are separated, the liquid water is prevented from flowing from one of the MEAs 21 and 22 to the other. Therefore, a decrease in power generation performance due to the flow of liquid water into the anhydrous electrolyte membrane of the MEA 22 and elution of the electrolyte is prevented. The supply manifold 90 may also be provided for each MEA 21 and 22, similarly to the discharge manifolds 91a and 91b.

  Next, the structure in the accommodation holes 241 and 242 of the MEGA accommodation frame 2 will be described. As described above, since one MEA 21 includes a water-containing electrolyte membrane and the other MEA 22 includes an anhydrous electrolyte membrane, liquid water generated by power generation between the MEAs 21 and 22 is contained in the accommodation holes 241 and 242. The structure for interrupting the flow of is provided.

  FIG. 9 is a cross-sectional view of the fuel cell 9 taken along line Ly-Ly in FIG. More specifically, FIG. 9 shows a cross section in the vicinity of the partition wall 213 that separates the MEAs 21 and 22 from each other.

  The partition wall 213 has a substantially T-shaped cross section and separates the receiving holes 241 and 242 from each other. GDL43, MEA21, and GDL41 are laminated in this order in one accommodation hole 241, and GDL44, MEA22, and GDL42 are laminated in this order in the other accommodation hole 242.

  The MEA 21 includes a water-containing electrolyte membrane 210, a cathode electrode 211, and an anode electrode 212. The hydrated electrolyte membrane 210 is sandwiched between the anode electrode 212 and the cathode electrode 211. As described above, the water-containing electrolyte membrane 210 has high proton conductivity in a water-containing state.

  Each of the anode electrode 212 and the cathode electrode 211 is a catalyst electrode layer, and is formed as a porous layer having gas diffusibility and composed of catalyst-carrying conductive particles. For example, the anode electrode 212 and the cathode electrode 211 are formed as a dry coating film of catalyst ink that is a dispersion solution of platinum-supporting carbon.

  The MEA 21 is an example of a first power generation unit, and generates power by a reaction between oxygen in the air supplied from the cathode channel 120 and hydrogen gas supplied from the anode channel 32. The MEA 21 is provided on the upstream side of the cathode channel 120 so as to be sandwiched between the cathode side separator 12 and the anode side separator 3. Here, the direction of the cathode channel 120 coincides with the y-axis direction, the negative direction of the y-axis corresponds to the upstream side of the cathode channel 120, and the positive direction of the y-axis corresponds to the downstream side of the cathode channel 120. . For this reason, as described with reference to FIGS. 4 to 6, the MEA 21 can maintain the hydrated electrolyte membrane 210 in a water-containing state in a low temperature range. Note that the symbol X indicates a cross section of the cathode channel 120 along the line Lx-Lx.

  The MEA 21 is sandwiched between the GDLs 41 and 43 in the accommodation hole 241. An MPL (Micro Porous Layer) (not shown) is provided between the MEA 21 and the GDLs 41 and 43.

  The GDLs 41 and 43 have a function of allowing oxygen and hydrogen gas to reach the surfaces of the cathode electrode 211 and the anode electrode 212, respectively, and a function as a conductive path between the cathode side separator 12 and the anode side separator 3. The GDLs 41 and 43 are made of a fiber base material such as carbon fiber, a flow path member obtained by processing a metal plate such as so-called expanded metal, or a porous member such as foam metal. The MEA 21 and the GDLs 41 and 43 constitute a MEGA.

  The MEA 22 includes an anhydrous electrolyte membrane 220, a cathode electrode 221, and an anode electrode 222. The anhydrous electrolyte membrane 220 is sandwiched between the anode electrode 222 and the cathode electrode 221. As described above, the anhydrous electrolyte membrane 220 has high proton conductivity in a high temperature state. Note that the anode electrode 222 and the cathode electrode 221 have the same configuration as the anode electrode 212 and the cathode electrode 211 described above.

  The MEA 22 is an example of a second power generation unit, and generates power by a reaction between oxygen in the air supplied from the cathode channel 120 and hydrogen gas supplied from the anode channel 32. The MEA 22 is provided on the downstream side of the cathode channel 120 so as to be sandwiched between the cathode side separator 12 and the anode side separator 3. For this reason, the MEA 22 can maintain the anhydrous electrolyte membrane 220 in an anhydrous state in a high temperature region as described with reference to FIGS.

  The MEA 22 is sandwiched between the GDLs 42 and 44 in the accommodation hole 242. An MPL (not shown) is provided between the MEA 22 and the GDLs 42 and 44. The GDLs 42 and 44 have the same functions and configurations as the GDLs 41 and 43 described above. The MEA 22 and the GDLs 42 and 44 constitute a MEGA.

  Since the MEAs 21 and 22 are provided at appropriate positions in the direction of the cathode channel 120 as described above, higher power generation performance than the comparative example of FIG. 2 can be obtained. However, the water-containing electrolyte membrane 210 of one MEA 21 requires liquid water to exhibit proton conductivity, and the anhydrous electrolyte membrane 220 of the other MEA 22 is dry without liquid water to suppress electrolyte elution. Need a state.

  Therefore, the partition wall 213 of the MEGA housing frame 2 functions as a blocking unit that blocks the flow of liquid water generated by the power generation of the MEA 21 and the MEA 22. The lower part of the partition wall 213 is bonded to the upper plate portion 32a of the anode flow path 32 by an adhesive 51, and the wide part of the upper part of the partition wall 213 is bonded to the upper surfaces of the MEAs 21 and 22 by adhesives 52 and 53, respectively. ing. For this reason, the adhesives 51 to 53 and the upper plate part 32a block the flow of liquid water together with the partition wall 213 as a part of the blocking part.

  Thus, the partition wall 213 is provided between the cathode side separator 12 and the anode side separator 3 so as to separate the MEA 21 and the GDLs 41 and 43 from the MEA 22 and the GDLs 42 and 44. Therefore, the flow of liquid water is blocked between the MEA 21 and GDL 41, 43 and the MEA 22 and GDL 42, 44, and the liquid water generated by the power generation of one MEA 21 is prevented from flowing into the anhydrous electrolyte membrane 220 of the other MEA 22. The

  Therefore, the water-containing electrolyte membrane 210 of the MEA 21 is maintained in a water-containing state, and the anhydrous electrolyte membrane 220 of the MEA 22 is maintained in an anhydrous state in a high temperature range, so that higher power generation performance than the comparative example of FIG. 2 is obtained.

  In this example, the thickness Ta1 of the water-containing electrolyte membrane 210 is smaller than the thickness Ta2 of the anhydrous electrolyte membrane 220 (that is, Ta1 <Ta2). For example, the thickness Ta1 of the water-containing electrolyte membrane 210 is about 10 (μm), whereas the thickness Ta2 of the anhydrous electrolyte membrane 220 is about 50 (μm).

  For this reason, in this example, by making the thicknesses Tb1 and Tb2 of the GDLs 43 and 44 on the anode side of the MEAs 21 and 22 different, the difference in thickness (Ta1-Ta2) between the water-containing electrolyte membrane 210 and the anhydrous electrolyte membrane 220 is compensated. ing. It is assumed that the cathode electrodes 211 and 221 and the anode electrodes 212 and 222 have the same thickness, and the cathode-side GDLs 41 and 42 have the same thickness.

  The thickness Tb1 of the GDL 43 is larger than the thickness Tb2 of the GDL 44 (that is, Tb1> Tb2). The difference (Tb1−Tb2) between the thicknesses Tb1 and Tb2 of the GDLs 43 and 44 is determined based on the difference between the thicknesses of the water-containing electrolyte membrane 210 and the anhydrous electrolyte membrane 220 (Ta1−Ta2).

  For this reason, even if the depth of the cathode channel 120 and the anode channel 32 (height of the convex portion of the groove) is made uniform, the MEAs 21 and 22 and the GDLs 41 to 44 are placed between the cathode side separator 12 and the anode side separator 3. It becomes possible to pinch stably.

  The configuration shown in FIG. 9 is manufactured by the following procedure. First, GDLs 41 to 44 are laminated on each MEA 21, 22, and the cathode side end of each MEA 21, 22 is bonded to the partition wall 213 with adhesives 52, 53. Next, the lower part of the partition wall 213 is bonded to the anode side separator 3 with the adhesive 51, and the cathode side separator 12 is overlaid on the upper parts of the GDLs 41 and 42. In addition, the clearance gap S for the adhesives 51-53 to flow in is provided between the partition 213 and GDL41-44.

  In this example, the difference in thickness between the water-containing electrolyte membrane 210 and the anhydrous electrolyte membrane 220 is compensated by the thicknesses Tb1 and Tb2 of the GDLs 43 and 44. However, the present invention is not limited to this, and the MPL thickness or the total thickness of the MPL and GDL You may compensate. Furthermore, as in the following example, the difference between the thicknesses Ta1 and Ta2 of the water-containing electrolyte membrane 210 and the anhydrous electrolyte membrane 220 can be compensated by the height of the anode channel 32.

  FIG. 10 is a cross-sectional view showing another example of the fuel cell 9. In FIG. 10, the same reference numerals are given to configurations common to FIG. 9, and description thereof is omitted.

  In this example, it is assumed that the thicknesses Tb3 of the anode-side GDLs 43 and 44 are the same. Therefore, by making the depth Tc1 of the anode flow path 32 on the MEA 21 side different from the depth Tc2 of the anode flow path 32 on the MEA 22 side, the difference in thickness between the aqueous electrolyte membrane 210 and the anhydrous electrolyte membrane 220 (Ta1-Ta2). ) Is compensated.

  The depth Tc1 of the anode channel 32 on the MEA 21 side is deeper than the depth Tc2 of the anode channel 32 (that is, Tc1> Tc2). The difference (Tc1-Tc2) between the depths Tc1, Tc2 of the anode channels 32 on the MEA 21, 22 side is determined based on the difference in thickness (Ta1-Ta2) between the water-containing electrolyte membrane 210 and the anhydrous electrolyte membrane 220.

  For this reason, even if the thickness Tb3 of the anode-side GDLs 43 and 44 is the same, the MEA 21 and GDL 41 and 43 and the MEA 22 and GDL 42 and 44 can be stably sandwiched between the cathode-side separator 12 and the anode-side separator 3. Become.

  In the embodiment described above, the GDLs 41 and 42 on the cathode side of the MEAs 21 and 22 are separated by the partition wall 213 of the MEGA housing frame 2, but are not limited thereto. Since the boundary portion between the GDLs 41 and 42 on the cathode side and the MEAs 21 and 22 is hotter than the boundary portion between the GDLs 43 and 44 on the anode side and the MEAs 21 and 22, liquid water generated by power generation tends to be lost on the cathode side. Further, since the flow rate of air in the cathode flow channel 120 is larger than the flow rate of hydrogen gas in the anode flow channel 32, liquid water generated by power generation is easily lost on the cathode side.

  Accordingly, as in the following example, a configuration in which the GDLs 41 and 42 on the cathode side are not separated but a common GDL can be used.

  FIG. 11 is an exploded perspective view of another example of the fuel cell 9. In FIG. 11, the same reference numerals are given to components common to FIG. 8, and the description thereof is omitted.

  In this example, the cathode side GDL 45 is common between the MEAs 21 and 22. That is, the GDL 45 is stacked on both the MEAs 21 and 22. The GDL 45 is housed in the MEGA housing frame 2a together with the MEAs 21 and 22.

  The MEGA housing frame 2a has a pair of through holes 200, 201a, 201b formed at both ends in the y-axis direction, a housing hole 241a that houses the GDL 43, and a housing hole 242a that houses the GDL 44.

  The housing holes 241a and 242a are rectangular through holes provided side by side in the y direction, and are separated from each other via a partition wall 213a extending in the x axis direction. In FIG. 11, the GDLs 43 and 44 are shown accommodated in the accommodation holes 241a and 242a, respectively.

  Since the height (the length in the Z-axis direction) of the partition wall 213a in this example is lower than the partition wall 213 in the example of FIG. 8, the accommodation holes 241a and 242a are combined with the accommodation holes 241a and 242a and the upper part of the partition wall 213a. There is a space 243 that is about the size. The GDL 45 and the MEAs 21 and 22 are accommodated while being stacked in the space 243. Below, the structure in the accommodation holes 241a and 242a of the MEGA accommodation frame 2a and the space 243 will be described.

  FIG. 12 is a cross-sectional view of the fuel cell 9 taken along the line Ly′-Ly ′ of FIG. More specifically, FIG. 12 shows a cross section in the vicinity of the partition wall 213a separating the MEAs 21 and 22 from each other. In FIG. 12, the same components as those in FIG. 9 are denoted by the same reference numerals, and the description thereof is omitted.

  The partition wall 213a has a rectangular cross section and separates the receiving holes 241a and 242a from each other. The GDL 43 is accommodated in one accommodation hole 241a, and the GDL 44 is accommodated in the other accommodation hole 242a. Further, the GDL 45 and the MEAs 21 and 22 are accommodated in the space 243 above the accommodation holes 241a and 242a and the partition wall 213a.

  The GDL 45 is stacked on top of the MEAs 21 and 22. For this reason, the MEA 21 is sandwiched between the GDLs 45 and 43, and the MEA 22 is sandwiched between the GDLs 45 and 44. The GDL 45 has the same function and configuration as the GDLs 41 and 42 described above. MEA 21 and GDL 45, 43 and MEA 22 and GDL 45, 44 constitute MEGA, respectively.

  The partition wall 213a of the MEGA housing frame 2a functions as a part of a blocking unit that blocks the flow of liquid water generated by the power generation of the MEA 21 and the MEA 22. The bottom part of the partition wall 213a is bonded to the upper plate part 32a of the anode flow path 32 by an adhesive 55, and the upper part of the partition wall 213a is bonded to each end of the MEAs 21 and 22 and the lower part of the GDL 45 by an adhesive 54. Yes. Therefore, the adhesives 54 and 55 and the upper plate portion 32a constitute a blocking portion that blocks the flow of liquid water together with the partition wall 213a.

  Thus, the partition 213a and the adhesive 54 are provided between the cathode separator 12 and the anode separator 3 so as to separate the MEA 21 and GDL 43 from the MEA 22 and GDL 44. For this reason, the flow of liquid water is blocked between the MEA 21 and GDL 43 and the MEA 22 and GDL 44, and the liquid water generated by the power generation of one MEA 21 is prevented from flowing into the anhydrous electrolyte membrane 220 of the other MEA 22.

  Therefore, the water-containing electrolyte membrane 210 of the MEA 21 is maintained in a water-containing state, and the anhydrous electrolyte membrane 220 of the MEA 22 is maintained in an anhydrous state in a high temperature range, so that higher power generation performance than the comparative example of FIG. 2 is obtained.

  Further, in this example, as in the example of FIG. 9, the thickness difference Tb1 and Tb2 of the GDLs 43 and 44 on the anode side of the MEAs 21 and 22 is made different, whereby the difference in thickness between the water-containing electrolyte membrane 210 and the anhydrous electrolyte membrane 220 ( Ta1-Ta2) is compensated. For this reason, even if the depth of the cathode channel 120 and the anode channel 32 (height of the convex portion of the groove) is made uniform, the MEAs 21 and 22 and the GDLs 43 to 45 are placed between the cathode side separator 12 and the anode side separator 3. It becomes possible to pinch stably. In this example, as in the example of FIG. 10, it is possible to compensate for the difference between the thicknesses Ta1 and Ta2 of the water-containing electrolyte membrane 210 and the anhydrous electrolyte membrane 220 by the height of the anode channel 32, Compensation by the thickness of MPL or the total thickness of MPL and GDL is also possible.

  Furthermore, in this example, compared with the example of FIG. 9, since the GDL 45 on the cathode side is common between the MEAs 21 and 22, the number of parts is reduced, and the manufacturing cost is reduced.

  The configuration shown in FIG. 12 is manufactured by the following procedure. First, GDLs 43 to 45 are stacked on each MEA 21, 22, and the anode side end of each MEA 21, 22 is bonded to the partition wall 213 a with an adhesive 54. Next, the lower part of the partition wall 213a is bonded to the anode side separator 3 with the adhesive 55, and the cathode side separator 12 is overlaid on the upper part of the GDL 45. A gap S for allowing the adhesives 54 and 55 to flow in is provided between the partition wall 213a and the GDLs 43 and 44.

  As described above, the fuel cell 9 according to the embodiment is cooled by supplying air, and includes the cathode separator 12, the anode separator 3, the MEAs 21 and 22, and the partition walls 213 and 213a. The cathode side separator 12 is provided with a cathode channel 120 for supplying air, and the anode side separator 3 is provided with an anode channel 32 for supplying hydrogen gas.

  The MEA 21 is provided on the upstream side of the cathode channel 120 so as to be sandwiched between the cathode side separator 12 and the anode side separator 3, and the reaction between the air supplied from the cathode channel 120 and the hydrogen gas supplied from the anode channel 32. To generate electricity. The MEA 22 is provided on the downstream side of the cathode channel 120 so as to be sandwiched between the cathode side separator 12 and the anode side separator 3, and the air supplied from the cathode channel 120 and the hydrogen gas supplied from the anode channel 32. Power is generated by the reaction of Further, the partition walls 213 and 213a block the flow of liquid water generated by the power generation of the MEAs 21 and 22.

  The MEA 21 has a water-containing electrolyte membrane 210 having proton conductivity in a water-containing state, and the MEA 22 has an anhydrous electrolyte membrane 220 having proton conductivity in a high-temperature state of 80 ° C. or higher. The partition walls 213 and 213a separate at least the region on the anode side separator 3 side from the aqueous electrolyte membrane 210 from the region on the anode side separator 3 side from the anhydrous electrolyte membrane 220 between the cathode side separator 12 and the anode side separator 3. Is provided.

  According to the above configuration, as shown in FIG. 4, the MEA 21 including the water-containing electrolyte membrane 210 is disposed in the region A1 upstream of the cathode flow channel 120, and the MEA 22 including the anhydrous electrolyte membrane 220 is disposed in the cathode flow channel 120. It arrange | positions in area | region A2 of a downstream side. For this reason, since the MEA 21 can maintain the water-containing electrolyte membrane 210 in a water-containing state in a low temperature region, the water-containing electrolyte membrane 210 can exhibit proton conductivity. Further, since the MEA 22 can maintain the anhydrous electrolyte membrane 220 in an anhydrous state in a high temperature region, the anhydrous electrolyte membrane 220 can exhibit proton conductivity.

  In addition, the partition walls 213 and 213a are located between the cathode separator 12 and the anode separator 3 at least in the region from the hydrated electrolyte membrane 210 to the anode separator 3, and from the region from the anhydrous electrolyte membrane 220 to the anode separator 3 side. It is provided so as to be separated. For this reason, the flow of liquid water is blocked between the MEA 21 and GDL 43 and the MEA 22 and GDL 44, and the liquid water generated by the power generation of one MEA 21 is prevented from flowing into the anhydrous electrolyte membrane 220 of the other MEA 22. Thereby, the elution of the electrolyte of the anhydrous electrolyte membrane 220 is suppressed.

  Therefore, the water-containing electrolyte membrane 210 of the MEA 21 is maintained in a water-containing state, and the anhydrous electrolyte membrane 220 of the MEA 22 is maintained in an anhydrous state, so that higher power generation performance than the comparative example of FIG. 2 is obtained. Therefore, the fuel cell 9 of the embodiment can improve the power generation performance without being limited in size.

  The above-described embodiment is an example of a preferred embodiment of the present invention. However, the present invention is not limited to this, and various modifications can be made without departing from the scope of the present invention.

9 Fuel cell 2, 2a MEGA housing frame 3 Anode separator (second supply unit)
12 Cathode side separator (1st supply part)
21, 22 MEA (first and second power generation units)
32 Anode channel (second channel)
41-45 GDL
120 cathode channel (first channel)
210 Aqueous electrolyte membrane (first electrolyte membrane)
220 Anhydrous electrolyte membrane (second electrolyte membrane)
213, 213a Bulkhead (blocking part)

Claims (1)

A fuel cell cooled by the supply of an oxidant gas,
A first supply unit provided with a first flow path for supplying the oxidant gas;
A second supply section provided with a second flow path for supplying fuel gas;
Provided on the upstream side of the first flow path so as to be sandwiched between the first supply section and the second supply section, and supplied from the oxidant gas supplied from the first flow path and the second flow path. A first power generation unit that generates power by reaction of the fuel gas;
Provided on the downstream side of the first flow path so as to be sandwiched between the first supply section and the second supply section, and supplied from the oxidant gas supplied from the first flow path and the second flow path. A second power generation unit that generates power by reaction of the fuel gas;
A blocking unit that blocks the flow of liquid water generated by the power generation of the first power generation unit and the second power generation unit;
The first power generation unit includes a first electrolyte membrane having proton conductivity in a water-containing state,
The second power generation unit includes a second electrolyte membrane having proton conductivity in a high temperature state of 80 ° C. or higher,
The blocking section is located between the first supply section and the second supply section, at least from the first electrolyte membrane to the second supply section side, and from the second electrolyte membrane to the second supply section side. A fuel cell provided so as to be separated from the region.

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