JP2017216051A - Fuel cell system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the degree of freedom in a piping layout, while suppressing liquid junction by ensuring ground fault resistance of a coolant pipe.SOLUTION: A fuel cell system 10 comprises a fuel cell stack 14 in which a plurality of power generation cells 28 are stacked on top of each other. A cooling medium passage formation member 24 is arranged under the fuel cell stack 14. A stack external supply labyrinth passage 90 is formed inside the cooling medium passage formation member 24, while a stack internal supply labyrinth passage 72 is formed inside a first end plate 34a. The stack external supply labyrinth passage 90 is connected to the stack internal supply labyrinth passage 72 via an inlet hole 96a.SELECTED DRAWING: Figure 3

Description

  The present invention includes a fuel cell stack in which a plurality of power generation cells that generate power by an electrochemical reaction between a fuel gas and an oxidant gas are stacked, and a cooling medium flow path for circulating a cooling medium inside the fuel cell stack The present invention relates to a fuel cell system.

  For example, a polymer electrolyte fuel cell has an electrolyte membrane / electrode structure (MEA) in which an anode electrode is disposed on one surface of an electrolyte membrane made of a polymer ion exchange membrane and a cathode electrode is disposed on the other surface. It has. The electrolyte membrane / electrode structure is sandwiched between separators to constitute a power generation cell (unit cell). Usually, a predetermined number of power generation cells are stacked, for example, incorporated in a fuel cell vehicle (fuel cell electric vehicle or the like) as an in-vehicle fuel cell stack.

  An electric vehicle such as a fuel cell vehicle needs to satisfy electric safety regulations such as ECE-R100 and FMVSS305. For this reason, the electric powertrain as a whole is required to satisfy the legally required ground fault resistance. Therefore, the total of the shared resistance of each device (equipment) (the ground fault resistance between each device and the chassis GND that is the ground potential of the fuel cell vehicle) is set to exceed the legally required ground fault resistance.

  For example, in a fuel cell stack, there are a gas system, a stack peripheral system, a cooling system, and the like as high-voltage devices, each of which has a shared resistance. In the cooling system, a radiator, a refrigerant pump, an auxiliary device, and the like are grounded to the chassis GND. For this reason, in order to ensure the ground fault resistance of the cooling system more than the shared resistance, the refrigerant conductivity management and the pipe layout (pipe diameter, length, etc.) to the device grounded to the chassis GND are appropriately set. There is a need to.

  As a facility having this type of cooling system, for example, a fuel cell system disclosed in Patent Document 1 is known. In this fuel cell system, a first refrigerant system that circulates and supplies a refrigerant to a first circulation path including an in-cell refrigerant flow path and a refrigerant cooling device inside the fuel cell, the in-battery refrigerant flow path and an ion exchanger, And a second refrigerant system that circulates and supplies the refrigerant to the second circulation path. In controlling the refrigerant circulation by the first refrigerant system and the second refrigerant system, when the fuel cell is started, the refrigerant supply to the fuel cell by the second refrigerant system is preceded over a predetermined priority period. And running.

  All of the refrigerant passing through the second circulation path of the second refrigerant system is repeatedly passed through the ion exchanger after passing through the refrigerant flow path in the fuel cell from the beginning of the priority period, and the ions are removed. . Therefore, the refrigerant flow path in the fuel cell quickly circulates the refrigerant having a low conductivity in the priority period, so that the insulation deterioration of the fuel cell that occurs due to the presence of the refrigerant is quickly and highly effective. It can be avoided by sex.

JP 2014-157832 A

  By the way, in a fuel cell vehicle, when left in a high temperature environment for a long time, the refrigerant conductivity increases. In other words, since the refrigerant does not circulate during standing, ion removal by the ion exchanger is not performed, and the refrigerant conductivity may increase and the electric resistance in the refrigerant system may be reduced. The increase in the refrigerant conductivity is particularly caused by liquid contact with a metal member such as a radiator or a metal separator. Therefore, the ground fault resistance between the fuel cell stack and the chassis GND decreases under the worst condition such as leaving at a high temperature, and there is a possibility that a desired shared ground fault resistance cannot be ensured.

  Therefore, for example, it is conceivable to lengthen the refrigerant pipe length. However, in a space in which the fuel cell system is accommodated, for example, in a motor room, there is a problem that long pipes are entangled and the maintainability is lowered.

  In addition, when an external load such as a collision is applied, the refrigerant pipe is likely to interfere with various devices that are densely arranged, and the refrigerant pipe may be damaged. At that time, the ground fault resistance from the fuel cell stack, which is the live part, to the damaged part of the refrigerant pipe is lower than the desired shared ground fault resistance, and there is a possibility that a liquid junction occurs.

  The present invention solves this type of problem, and provides a fuel cell system that can ensure ground fault resistance of refrigerant piping and suppress liquid junction, and can effectively improve the degree of freedom of piping layout. The purpose is to provide.

  A fuel cell system according to the present invention includes a fuel cell stack in which a plurality of power generation cells that generate power by an electrochemical reaction between a fuel gas and an oxidant gas are stacked, and a cooling medium is circulated inside the fuel cell stack. A cooling medium flow path is formed.

  The fuel cell system includes a cooling medium flow path component having a first labyrinth flow path having a curved shape or a bent shape. The cooling medium flow path component is provided with a circulation port connected to the cooling medium flow path of the fuel cell stack. The fuel cell stack has an end plate disposed at an end portion in the stacking direction of the power generation cells, and at least one of the end plates has a curved shape or a bent shape in order to connect the first labyrinth channel and the cooling medium channel. A second labyrinth flow path is provided.

  In this fuel cell system, it is preferable that the cooling medium flow path component is disposed in contact with the bottom of the fuel cell stack, and the first labyrinth flow path and the second labyrinth flow path are directly connected. .

  According to the present invention, the cooling medium flow path component is provided with the first labyrinth flow path, and the cooling medium flow path component is connected to the cooling medium flow path of the fuel cell stack. In addition, the end plate is provided with a second labyrinth channel that connects the first labyrinth channel and the cooling medium channel.

  Therefore, since the first labyrinth flow path and the second labyrinth flow path, which are long flow paths, are provided, the conductive resistance of the cooling medium flow path system can be increased, and the shared ground fault resistance required by law is satisfied. It is possible to secure a creepage distance. As a result, it is possible to secure ground fault resistance of the refrigerant piping and suppress liquid junction, and to effectively improve the degree of freedom of piping layout.

It is a schematic explanatory drawing of the front part of the fuel cell vehicle to which the fuel cell system concerning a 1st embodiment of the present invention is applied. It is principal part explanatory drawing of the said fuel cell system. It is a principal part disassembled perspective explanatory drawing of the said fuel cell system. It is a disassembled perspective view of the electric power generation cell which comprises the said fuel cell system. It is a partial cross section front view of the 1st end plate which comprises the said fuel cell system. It is a section front view of the 2nd end plate which constitutes the fuel cell system. It is a plane explanatory view of a cooling medium flow path constituent member which constitutes the fuel cell system. In the said fuel cell system, it is explanatory drawing when supply piping and discharge piping are damaged. It is a principal part disassembled perspective explanatory drawing of the fuel cell system which concerns on the 2nd Embodiment of this invention. It is a cross-sectional front view of the 1st end plate which comprises the said fuel cell system. It is a plane explanatory view of the 1st case part of the cooling-medium channel constituent member which constitutes the fuel cell system. It is a plane explanatory view of the 2nd case part of the above-mentioned cooling medium channel constituent member.

  As shown in FIG. 1, the fuel cell system 10 according to the first embodiment of the present invention is mounted on a fuel cell vehicle 12 such as a fuel cell electric vehicle. The fuel cell system 10 includes a fuel cell stack 14, and the fuel cell stack 14 is disposed in a motor room (front box) 16 of the fuel cell vehicle 12.

  In the motor room 16, a traveling motor 18 and a PDU (Power Drive Unit) 20 are disposed. The PDU 20 performs system management of the entire fuel cell vehicle 12, and has a function of converting DC power of a battery (not shown) and the fuel cell into three-phase AC power and transmitting it to the traveling motor 18.

  In the fuel cell stack 14, a voltage control unit (VCU) (Voltage Control Unit) 22 is placed in contact with the upper part, and a cooling medium flow path component 24 is arranged in contact with the lower part (bottom part). 26 are integrally covered. The voltage control unit 22 has a function of controlling the output of the fuel cell stack 14 and may be disposed outside the casing 26. The cooling medium flow path constituting member 24 constitutes a cooling medium supply device 27, which will be described later.

  As shown in FIGS. 2 and 3, in the fuel cell stack 14, a plurality of power generation cells 28 are stacked in the vehicle width direction (arrow A direction). As shown in FIG. 3, the first terminal plate 30 a, the first insulating plate 32 a, and the first end plate 34 a are sequentially disposed at one end in the stacking direction of the power generation cells 28 toward the outside. At the other end of the power generation cell 28 in the stacking direction, a second terminal plate 30b, a second insulating plate 32b, and a second end plate 34b are sequentially disposed outward. The first terminal plate 30a and the second terminal plate 30b are provided with a terminal portion 30at and a terminal portion 30bt protruding upward on each upper side.

  The 1st insulating plate 32a and the 2nd insulating plate 32b are comprised with the resin material which has electrical insulation. Although the first end plate 34a and the second end plate 34b are made of a resin material having electrical insulation, for example, a resin coat may be applied to an aluminum base material. Between the sides of the first end plate 34a and the second end plate 34b, both ends of the connecting bar 36 are fixed by screws 38, and a tightening load in the stacking direction (arrow A direction) is applied to the plurality of stacked power generation cells 28. Give.

  As shown in FIG. 4, the power generation cell 28 has a rectangular shape that is long in the arrow B direction. The power generation cell 28 includes an electrolyte membrane / electrode structure 40, and a cathode separator 42 and an anode separator 44 that sandwich the electrolyte membrane / electrode structure 40. The cathode separator 42 and the anode separator 44 have a horizontally long (or vertically long) rectangular shape. The cathode separator 42 and the anode separator 44 are constituted by a metal separator or a carbon separator.

  An oxidant gas supply communication hole 46a and a fuel gas discharge communication hole 48b are provided at one end edge of the power generation cell 28 in the long side direction (arrow B direction), respectively, in the direction of arrow A which is the stacking direction. It is done. The oxidant gas supply communication hole 46a supplies an oxidant gas, for example, an oxygen-containing gas, while the fuel gas discharge communication hole 48b discharges a fuel gas, for example, a hydrogen-containing gas.

  The other end edge of the power generation cell 28 in the long side direction is individually communicated in the direction of arrow A, which is the stacking direction, and the fuel gas supply communication hole 48a for supplying fuel gas and the oxidant gas are discharged. An oxidant gas discharge communication hole 46b is provided.

  A pair of cooling medium supply communication holes 50a is provided on one side (vertical direction upper side) of the power generation cell 28 in the short side direction (arrow C direction). The cooling medium supply communication holes 50a individually communicate with each other in the direction of arrow A in order to supply the cooling medium. A pair of cooling medium discharge communication holes 50 b is provided on the other side (vertical direction lower side) of the power generation cell 28 in the short side direction. The cooling medium discharge communication holes 50b individually communicate with each other in the direction of arrow A in order to discharge the cooling medium.

  The electrolyte membrane / electrode structure 40 includes, for example, a solid polymer electrolyte membrane 52 that is a thin film of moisture containing perfluorosulfonic acid, and a cathode electrode 54 and an anode electrode 56 that sandwich the solid polymer electrolyte membrane 52. Prepare. The solid polymer electrolyte membrane 52 is a cation exchange membrane, and an HC (hydrocarbon) electrolyte may be used in addition to the fluorine electrolyte.

  The cathode electrode 54 and the anode electrode 56 have a gas diffusion layer (not shown) made of carbon paper or the like. The porous carbon particles carrying the platinum alloy on the surface are uniformly applied to the surface of the gas diffusion layer, thereby forming an electrode catalyst layer (not shown). The electrode catalyst layers are formed on both surfaces of the solid polymer electrolyte membrane 52.

  An oxidant gas flow path 58 that connects the oxidant gas supply communication hole 46a and the oxidant gas discharge communication hole 46b is formed on the surface 42a of the cathode separator 42 facing the electrolyte membrane / electrode structure 40. The oxidant gas channel 58 is formed by a plurality of wavy channel grooves (or straight channel grooves) extending in the arrow B direction.

  A fuel gas flow path 60 that connects the fuel gas supply communication hole 48 a and the fuel gas discharge communication hole 48 b is formed on the surface 44 a of the anode separator 44 facing the electrolyte membrane / electrode structure 40. The fuel gas channel 60 is formed by a plurality of wavy channel grooves (or linear channel grooves) extending in the direction of arrow B.

  A cooling medium flow path 62 communicating with the pair of cooling medium supply communication holes 50a and the pair of cooling medium discharge communication holes 50b is formed between the surface 44b of the anode separator 44 and the surface 42b of the cathode separator 42 adjacent to each other. Is done. The cooling medium flow path 62 extends in the vertical direction, and allows the cooling medium to flow from above to below over the electrode range of the electrolyte membrane / electrode structure 40.

  A first seal member 64 is integrally formed on the surfaces 42 a and 42 b of the cathode separator 42 around the outer peripheral edge of the cathode separator 42. A second seal member 66 is integrally formed on the surfaces 44 a and 44 b of the anode separator 44 around the outer peripheral edge of the anode separator 44.

  As the first seal member 64 and the second seal member 66, for example, EPDM, NBR, fluorine rubber, silicone rubber, fluorosilicone rubber, butyl rubber, natural rubber, styrene rubber, chloroprene or acrylic rubber or the like, cushion material Alternatively, an elastic seal member such as a packing material is used.

  As shown in FIG. 3, the first insulating plate 32a and the first end plate 34a have an oxidant gas supply communication hole 46a, a fuel gas discharge communication hole 48b, a fuel gas supply communication hole 48a, and an oxidant gas discharge communication hole 46b. Is formed. A pair of cooling medium supply communication holes 50a and a pair of cooling medium discharge communication holes 50b are formed in the second insulating plate 32b and the second end plate 34b.

  The first end plate 34a is provided with an oxidant gas inlet manifold 68a, an oxidant gas outlet manifold 68b, a fuel gas inlet manifold 70a, and a fuel gas outlet manifold 70b. The oxidant gas inlet manifold 68a and the oxidant gas outlet manifold 68b communicate with the oxidant gas supply communication hole 46a and the oxidant gas discharge communication hole 46b. The fuel gas inlet manifold 70a and the fuel gas outlet manifold 70b communicate with the fuel gas supply communication hole 48a and the fuel gas discharge communication hole 48b.

  As shown in FIGS. 3 and 5, an in-stack supply labyrinth flow path (second labyrinth flow path) 72 having an L-shaped bent shape (or curved shape) is formed inside the first end plate 34a. The The in-stack supply labyrinth flow path 72 is not limited to an L shape, and may have a shape meandering inside the first end plate 34a. When the first end plate 34a is made of a metal material, the inner surface of the in-stack supply labyrinth flow path 72 is preferably coated with a resin. A supply port 72a that opens downward from the bottom surface of the first end plate 34a is provided at the lower end in the vertical direction of the supply labyrinth flow path 72 in the stack. The upper portion of the in-stack supply labyrinth flow path 72 extending in the horizontal direction communicates with the pair of cooling medium supply communication holes 50 a in the fuel cell stack 14 and is connected to each cooling medium flow path 62.

  As shown in FIG. 6, a discharge chamber 74 is formed inside the second end plate 34b. A plurality of plate-like portions 76 are arranged in a staggered manner in the discharge chamber 74, thereby forming an in-stack discharge labyrinth flow path (second labyrinth flow path) 78 having meandering portions and meandering. . The folded portion preferably forms a bent shape or a curved shape.

  The in-stack discharge labyrinth flow path 78 is directed upward while meandering in the horizontal direction, extends vertically downward from the upper end, and is opened downward from the bottom surface of the second end plate 34b to the lower end of the vertical direction. A discharge port 78a is provided. The lowest end portion of the in-stack discharge labyrinth flow path 78 extending in the horizontal direction communicates with the pair of cooling medium discharge communication holes 50 b in the fuel cell stack 14 and is connected to each cooling medium flow path 62.

  In the fuel cell stack 14, the power generation cell 28 closest to the first end plate 34a is arranged with the cathode electrode 54 facing the first end plate 34a. In the fuel cell stack 14, the power generation cell 28 closest to the second end plate 34b is disposed with the anode electrode 56 facing the second end plate 34b.

  As shown in FIG. 3, the cooling medium flow path constituting member 24 is formed of an insulating member having electrical insulation, and includes a housing portion 80 and a lid portion 82. The casing 80 is open at the top, and a supply chamber 86a and a discharge chamber 86b are separately formed in the inside via a partition plate 84.

  As shown in FIGS. 3 and 7, a plurality of plate members 88 are arranged in a staggered manner in the supply chamber 86a, whereby the supply labyrinth flow path outside the stack (first first) meandering with a folded portion. Labyrinth channel) 90 is formed. A plurality of plate members 92 are arranged in a staggered manner in the discharge chamber 86b, thereby forming an out-stack discharge labyrinth flow path (first labyrinth flow path) 94 having meandering portions and meandering.

  As shown in FIG. 3, the lid 82 has an inlet hole 96a that connects the outlet side of the out-stack supply labyrinth flow path 90 and the supply port 72a of the in-stack supply labyrinth flow path 72 of the first end plate 34a. Is formed. The lid portion 82 is formed with an outlet hole portion 96b that connects the inlet side of the out-stack discharge labyrinth channel 94 and the discharge port 78a of the in-stack discharge labyrinth channel 78 of the second end plate 34b.

  On the front surface of the housing 80, one end of a supply pipe 98 a connected to the inlet side of the out-stack supply labyrinth flow path 90 and one end of a discharge pipe 98 b connected to the outlet side of the out-stack discharge labyrinth flow path 94 Are connected.

  An ion exchanger 100 is disposed on the front surface of the casing unit 80. The supply piping 98a and the inlet side of the ion exchanger 100 are connected via an inlet hole (equipment flow port) 102a. The discharge pipe 98b and the outlet side of the ion exchanger 100 are connected via an outlet hole (equipment flow port) 102b.

  As shown in FIG. 2, the other end of the supply pipe 98 a communicates with the outlet side of the radiator 104, while the other end of the discharge pipe 98 b communicates with the inlet side of the radiator 104. A refrigerant pump 106 and a three-way valve 108 for circulating the refrigerant are disposed in the supply pipe 98a, and the three-way valve 108 and the discharge pipe 98b are connected by a bypass line 110. An auxiliary device (such as an air conditioner system) 114 is connected to the discharge pipe 98b via a circulation line 112. The radiator 104, the refrigerant pump 106, and the auxiliary device 114 are electrically connected to a chassis GND (not shown) that is the ground potential of the fuel cell vehicle 12. A three-way valve 107 is disposed in the middle of the discharge pipe 98b, and a circulation line 112 is connected to the three-way valve 107. When the auxiliary device 114 does not require a refrigerant, the three-way valve 107 is switched to bypass the refrigerant to the radiator 104 side.

  Although not shown, the fuel cell stack 14 is provided with a fuel gas supply device that supplies a fuel gas (for example, hydrogen gas) and an oxidant gas supply device that supplies an oxidant gas (for example, air).

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

  As shown in FIG. 3, an oxygen-containing gas, for example, air is supplied from an oxidant gas supply device (not shown) from the oxidant gas inlet manifold 68a of the first end plate 34a to the oxidant gas supply communication hole 46a. Is done. On the other hand, a hydrogen-containing gas, for example, hydrogen gas, is supplied from a fuel gas supply device (not shown) from the fuel gas inlet manifold 70a of the first end plate 34a constituting the fuel cell stack 14 to the fuel gas supply communication hole 48a. Is done.

  Therefore, as shown in FIG. 4, air is introduced into the oxidant gas flow path 58 of the cathode separator 42 from the oxidant gas supply communication hole 46 a. The air flows in the direction of arrow B along the oxidant gas flow path 58 and is supplied to the cathode electrode 54 of the electrolyte membrane / electrode structure 40.

  On the other hand, the hydrogen gas is supplied to the fuel gas channel 60 of the anode separator 44 from the fuel gas supply communication hole 48a. The hydrogen gas flows in the direction of arrow B along the fuel gas flow path 60 and is supplied to the anode electrode 56 of the electrolyte membrane / electrode structure 40.

  Therefore, in the electrolyte membrane / electrode structure 40, oxygen in the air supplied to the cathode electrode 54 and hydrogen gas supplied to the anode electrode 56 are consumed by an electrochemical reaction in the electrode catalyst layer to generate power. Done.

  Next, the air that is partially consumed by being supplied to the cathode electrode 54 of the electrolyte membrane / electrode structure 40 is discharged in the direction of arrow A along the oxidant gas discharge communication hole 46b. On the other hand, the hydrogen gas supplied to the anode electrode 56 of the electrolyte membrane / electrode structure 40 and partially consumed is discharged in the direction of arrow A along the fuel gas discharge communication hole 48b. As shown in FIG. 3, air is discharged from the oxidant gas outlet manifold 68b, and hydrogen gas is discharged from the fuel gas outlet manifold 70b.

  As shown in FIG. 2, in the cooling medium supply device 27, a cooling medium such as pure water, ethylene glycol, or oil is supplied to the supply pipe 98 a under the action of the refrigerant pump 106. The cooling medium flows so as to meander along the out-stack supply labyrinth flow path 90 of the cooling medium flow path component 24, and is then supplied from the supply port 72a of the first end plate 34a to the in-stack supply labyrinth flow path 72. The

  As shown in FIG. 5, the cooling medium flows in an L shape along the in-stack supply labyrinth flow path 72 and is then supplied to the pair of cooling medium supply communication holes 50 a in the fuel cell stack 14. As shown in FIG. 4, the cooling medium supplied to the pair of cooling medium supply communication holes 50 a is introduced into the cooling medium flow path 62 between the cathode separator 42 and the anode separator 44 adjacent to each other. The cooling medium flows through the cooling medium flow path 62 from above to below, thereby cooling the electrolyte membrane / electrode structure 40. The cooling medium is discharged to a pair of cooling medium discharge communication holes 50b provided below and flows along the direction of arrow A.

  The cooling medium is introduced into the lower side of the in-stack discharge labyrinth flow path 78 of the second end plate 34 b after cooling each power generation cell 28. As shown in FIG. 6, the in-stack discharge labyrinth flow path 78 meanders in the plane of the second end plate 34b, and the cooling medium meanders along the in-stack discharge labyrinth flow path 78 while moving downward. It flows upward from. Then, the cooling medium flows vertically downward from the upper end of the in-stack discharge labyrinth flow path 78 and is discharged from the discharge port 78a to the out-stack discharge labyrinth flow path 94 (see FIGS. 3 and 7).

  The cooling medium flowing while meandering through the out-stack discharge labyrinth flow path 94 is discharged to the discharge pipe 98b. As shown in FIG. 2, while the cooling medium is introduced into the radiator 104 and cooled, a part of the cooling medium adjusts the temperature of the auxiliary device 114 via the circulation line 112. Further, if the temperature of the cooling medium is relatively low, the cooling medium flows through the bypass line 110 bypassing the radiator 104.

  In the cooling medium supply device 27, when the fuel cell stack 14 is left standing for a long time and then started, the cooling medium bypasses the fuel cell stack 14 and is supplied to the ion exchanger 100. For this reason, the ions mixed in the cooling medium are removed, and the refrigerant conductivity can be reduced.

  In this case, in the first embodiment, as shown in FIGS. 2, 3, and 7, the cooling medium flow path constituting member 24 includes a meandering long off-stack supply labyrinth flow path 90 and an out-stack discharge labyrinth. A flow path 94 is provided. In addition, as shown in FIG. 5, the first end plate 34 a is provided with an in-stack supply labyrinth flow path 72 that connects the out-stack supply labyrinth flow path 90 and the cooling medium flow path 62. Furthermore, as shown in FIG. 6, the second end plate 34 b is provided with an in-stack discharge labyrinth flow path 78 that connects the out-stack discharge labyrinth flow path 94 and the cooling medium flow path 62.

  As described above, the out-stack supply labyrinth channel 90 and the in-stack supply labyrinth channel 72, the out-stack discharge labyrinth channel 94, and the in-stack discharge labyrinth channel 78, which are long channels, are provided. . Therefore, it is possible to secure a creepage distance that satisfies the sharing ground resistance required by the law. Here, the refrigerant system ground fault resistance = (1 / refrigerant conductivity) × (pipe length / pipe cross-sectional area). The pipe cross-sectional area is a cross-sectional area of a circular flow path shape or an elliptical flow path shape.

  The lengths (pipe lengths) of the out-stack supply labyrinth channel 90 and the in-stack supply labyrinth channel 72, and the out-stack discharge labyrinth channel 94 and the in-stack discharge labyrinth channel 78 are considerably long. It has become. Thereby, refrigerant system ground fault resistance is set high, and can exceed desired sharing ground fault resistance.

  Furthermore, when an external load is applied to the fuel cell vehicle 12 due to a collision or the like, as shown in FIG. 8, at least one of the supply pipe 98a and the discharge pipe 98b may be damaged. At that time, the supply pipe 98a and the fuel cell stack 14 which is a live part are connected by an out-stack supply labyrinth flow path 90 and an in-stack supply labyrinth flow path 72 which are long flow paths. On the other hand, the discharge pipe 98b and the fuel cell stack 14 are connected by an out-stack discharge labyrinth flow path 94 and an in-stack discharge labyrinth flow path 78, which are long flow paths.

  For this reason, the ground fault resistance from the fuel cell stack 14 to the refrigerant pipe breakage site can be secured to a value that exceeds the desired shared ground fault resistance. Therefore, it is possible to obtain an effect that the ground fault resistance of the refrigerant pipe is ensured and the liquid junction is suppressed, and the degree of freedom of the pipe layout can be effectively improved.

  Furthermore, the cooling medium flow path component 24 is disposed in contact with the lower portion of the fuel cell stack 14, and the out-stack supply labyrinth flow path 90 and the in-stack supply labyrinth flow path 72 are directly connected. Similarly, the out-stack discharge labyrinth flow path 94 and the in-stack discharge labyrinth flow path 78 are directly connected.

  Thereby, there is no need to dispose a cooling medium manifold between the cooling medium flow path component 24 and the first end plate 34a, and the effect that the configuration is simplified and economical is obtained. The fuel cell stack 14 can have a function of keeping the end cell (the power generation cell 28 disposed at the end in the stacking direction) warm.

  The power generation cell 28 closest to the second end plate 34b is arranged with the anode electrode 56 facing the second end plate 34b. Since the anode electrode 56 generates a small amount of heat, the temperature environment of the power generation cell 28 at the end where the anode electrode 56 side is disposed on the second end plate 34b is lower than that of the other power generation cells 28, so Power generation stability due to generation is likely to deteriorate.

  For this reason, the second end plate 34b is provided with a long in-stack discharge labyrinth flow path 78, and the cooling medium heated by the exhaust heat at the time of power generation is caused to flow through the in-stack discharge labyrinth flow path 78. The power generation stability of the power generation cell 28 can be improved.

  FIG. 9 is an exploded perspective view of a main part of a fuel cell system 120 according to the second embodiment of the present invention. Note that the same components as those of the fuel cell system 10 according to the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  The fuel cell system 120 includes a fuel cell stack 122 and a coolant flow path component 124 disposed in contact with the lower portion of the fuel cell stack 122. The fuel cell stack 122 includes a first end plate 126 a disposed at one end in the stacking direction of the power generation cells 28 and a second end plate 126 b disposed at the other end in the stacking direction of the power generation cells 28.

  As shown in FIG. 10, an in-stack supply labyrinth channel 72 and an in-stack discharge labyrinth channel 78 are formed in the first end plate 126a. The second end plate 126b is not provided with a labyrinth flow path.

  As shown in FIG. 9, the cooling medium flow path component 124 is formed of an insulating member having electrical insulation, and includes a first casing portion 128, a second casing portion 130, and a lid portion 132, These are stacked in the vertical direction. An inlet hole 96a and an outlet hole 96b are formed on one end side in the longitudinal direction of the lid part 132.

  The first casing unit 128 arranged at the lowest position is opened at the top, and a discharge chamber 86b is formed inside. As shown in FIGS. 9 and 11, the discharge chamber 86b has a plurality of plate members 134 arranged in a staggered manner in the vehicle width direction so that the discharge outside the stack meanders with a folded portion. A labyrinth flow path (first labyrinth flow path) 136 is formed. The folded portion preferably forms a bent shape or a curved shape.

  The second housing part 130 disposed on the first housing part 128 is open at the top and is provided with a supply chamber 86a. An opening 138 that is located below the outlet hole 96b and communicates with the outlet hole 96b is formed at one corner of the supply chamber 86a so as to be cut off from the supply chamber 86a. As shown in FIG. 9 and FIG. 12, the supply chamber 86a has a plurality of plate members 140 arranged in a staggered manner in the vehicle length direction so that the supply outside the stack has a meandering portion. A labyrinth channel (first labyrinth channel) 142 is formed. The folded portion preferably forms a bent shape or a curved shape.

  One end of a discharge pipe 98 b connected to the outlet side of the out-stack discharge labyrinth flow path 136 is connected to the front surface of the first housing portion 128. One end of a supply pipe 98 a connected to the inlet side of the outside-stack supply labyrinth flow path 142 is connected to the front surface of the second housing part 130. The ion exchanger 100 is disposed on the front surface of the first housing portion 128 and the front surface of the second housing portion 130. The ion exchanger 100 is connected to an out-stack supply labyrinth flow path 142 and an out-stack discharge labyrinth flow path 136.

  In the second embodiment configured as described above, the first casing portion 128 has a plurality of plate members 134 arranged in a staggered manner to form an out-stack discharge labyrinth flow path 136. On the other hand, in the second housing part 130, a plurality of plate members 140 are arranged in a staggered manner to form an out-stack supply labyrinth flow path 142. Accordingly, the long out-of-stack discharge labyrinth flow path 136 and the out-of-stack supply labyrinth flow path 142 are provided vertically.

  The out-stack discharge labyrinth flow path 136 and the in-stack discharge labyrinth flow path 78 are connected, and the out-stack supply labyrinth flow path 142 and the in-stack supply labyrinth flow path 72 are connected. Thereby, in 2nd Embodiment, the effect similar to said 1st Embodiment is acquired.

DESCRIPTION OF SYMBOLS 10, 120 ... Fuel cell system 12 ... Fuel cell vehicle 14, 122 ... Fuel cell stack 16 ... Motor room 18 ... Driving motor 22 ... Voltage control unit 24, 124 ... Cooling medium flow path component 26 ... Casing 28 ... Power generation cell 34a, 34b, 126a, 126b ... end plate 40 ... electrolyte membrane / electrode structure 42 ... cathode separator 44 ... anode separator 46a ... oxidant gas supply communication hole 46b ... oxidant gas discharge communication hole 48a ... fuel gas supply communication hole 48b ... fuel gas discharge communication hole 50a ... cooling medium supply communication hole 50b ... cooling medium discharge communication hole 58 ... oxidant gas flow path 60 ... fuel gas flow path 62 ... cooling medium flow path 72 ... in-stack supply labyrinth flow path 72a ... supply Mouth 78 ... Stack labyrinth flow path 78a ... Ejection ports 80, 128, 130 ... Body part 82, 132 ... Lid part 86a ... Supply chamber 86b ... Discharge chamber 90, 142 ... Out-stack supply labyrinth channel 94, 136 ... Out-stack discharge labyrinth channel 96a ... Inlet hole 96b ... Outlet hole 98a ... Supply Pipe 98b ... Discharge pipe 100 ... Ion exchanger 104 ... Radiator 106 ... Refrigerant pump 107, 108 ... Three-way valve 114 ... Auxiliary device

Claims (2)

A fuel cell stack in which a plurality of power generation cells that generate power by an electrochemical reaction between a fuel gas and an oxidant gas is stacked, and a cooling medium flow path for circulating a cooling medium is formed inside the fuel cell stack. A fuel cell system,
A cooling medium flow path component provided with a first labyrinth flow path having a curved shape or a bent shape inside;
The cooling medium flow path component is provided with a circulation port connected to the cooling medium flow path of the fuel cell stack,
The fuel cell stack has an end plate disposed at an end portion in the stacking direction of the power generation cells, and at least one of the end plates has a curved shape so as to connect the first labyrinth flow path and the cooling medium flow path. Or the 2nd labyrinth flow path which has a bending shape is provided, The fuel cell system characterized by the above-mentioned.   2. The fuel cell system according to claim 1, wherein the coolant flow path component is disposed in contact with a bottom portion of the fuel cell stack, and the first labyrinth flow path and the second labyrinth flow path are provided. A fuel cell system that is directly connected.

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