JP5288225B2 - Fuel cell system - Google Patents

Description

  The present invention relates to a fuel cell system including a fuel cell that generates power upon receiving a reaction gas.

  In recent years, a fuel cell system using a fuel cell that generates electric power by an electrochemical reaction between a fuel gas and an oxidizing gas (hereinafter referred to as a reactive gas) has attracted attention. A fuel cell used in such a fuel cell system is configured as a fuel cell stack in which a plurality of single cells are stacked, and such a fuel cell stack is fixed and held on an end plate.

Such a fuel cell system includes a fuel gas circulation system that supplies fuel off-gas discharged from the fuel cell stack to the fuel cell stack again in order to effectively use the fuel gas (for example, Patent Documents). 1).
JP-A-2005-243505

  As described above, in a fuel cell system having a fuel gas circulation system, the fuel gas circulation system requires fuel gas circulation system components such as a circulation pump, a gas-liquid separator, or a discharge valve. If the piping length of the flow path connecting the battery stack and the fuel gas circulation system component is long, the thermal efficiency and the pump efficiency are lowered.

  Therefore, an object of the present invention is to provide a fuel cell system capable of shortening the piping length of a flow path that communicates a fuel cell stack and a fuel gas circulation system component.

In order to achieve the above object, a fuel cell system according to the present invention comprises a plurality of cells that generate power by an electrochemical reaction between a fuel gas and an oxidizing gas, and a pair of cells disposed at both ends in the stacking direction of the cells A fuel cell stack sandwiched between end plates, fuel gas supply system components for supplying fuel gas to the fuel cell stack, and fuel for supplying fuel off-gas discharged from the fuel cell stack to the fuel cell stack again A fuel cell system comprising: a motor unit that generates a rotational driving force; and a rotor unit that rotates with the driving force of the motor unit to suck and discharge gas. A circulating electric pump that regulates the circulation of the gas discharged from the fuel cell stack; a merging portion where the fuel gas and the fuel off-gas merge; the merging portion; A pipe for connecting a discharge port provided in the rotor part of the pump and a branch provided on the center side of the end plate for branching the fuel gas introduced from the merging part and supplying it to the fuel cell stack And
The rotor part side of the circulating electric pump is fixed to the center side of the end plate.

  With this configuration, the fuel gas circulation system components are fixed to the end plate that fixes the fuel cell stack, so the piping length of the flow path that connects the fuel cell stack and the fuel gas circulation system components is shortened. can do.

  Moreover, a gas-liquid separator that separates the gas-liquid of the fuel off-gas discharged from the fuel cell stack can be adopted as the fuel gas circulation system component.

  Furthermore, an exhaust valve that exhausts the fuel off-gas discharged from the fuel cell stack to the outside can be adopted as the fuel gas circulation system component.

  Moreover, you may arrange | position an electrical component under the said circulation electric pump.

  By setting it as this structure, it can suppress that the dew condensation of a fuel cell stack contacts an electrical component.

  By adopting such a configuration, it is possible to balance the weight and to suppress the vibration of the circulating electric pump.

  Further, when the fuel cell stack and a stack case for storing the fuel gas circulation system component are provided, a predetermined insulation distance is secured between the stack case and the fuel gas circulation system component. Also good.

  According to the present invention, it is possible to shorten the piping length of the flow path that connects the fuel cell stack and the fuel gas circulation system components, and as a result, it is possible to improve the thermal efficiency and the pump efficiency.

  Next, an embodiment of a fuel cell system according to the present invention will be described with reference to the drawings. In the drawings to be referred to, for convenience of illustration, of the constituent elements of the fuel cell system, the constituent elements referred to as pipes or pipe sections are simplified.

  FIG. 1 is a system configuration diagram of the fuel cell system 1. The fuel cell system 1 is used as an in-vehicle power generation system for fuel cell vehicles, a power generation system for any moving body such as a ship, an aircraft, a train, or a walking robot, and also as a power generation facility for buildings (housing, buildings, etc.). Although it can be applied to stationary power generation systems, it is specifically for automobiles.

  The fuel cell system 1 includes a plurality of fuel cell stacks 10A and 10B, which generate electric power by receiving a supply of reaction gases (oxidizing gas and fuel gas) and generating electric power through an electrochemical reaction. A cathode-based oxidizing gas piping system 2 that adjusts the supply of air as an oxidizing gas to the fuel cell stacks 10A and 10B; and an anode-based fuel gas piping system 3 that adjusts the supply of hydrogen gas as a fuel gas; It has.

  The oxidizing gas piping system 2 includes an air supply piping 21 that supplies each of the two fuel cell stacks 10A and 10B via two piping 21A and 21B branched from the oxidizing gas (air) humidified by the humidifier 20. An air discharge pipe 22 that leads the oxidant off-gas discharged from the fuel cell stacks 10A and 10B through the two systems of pipes 22A and 22B to the humidifier 20 after merging, and a discharge that guides the oxidant off-gas from the humidifier 20 to the outside. And a pipe 23. The air supply pipe 21 is provided with a compressor 24 that takes in the oxidizing gas in the atmosphere and pumps it to the humidifier 20.

  The fuel gas piping system 3 includes a hydrogen tank 30 as a fuel supply source storing high-pressure hydrogen gas, and two lines of piping 31A and 31B in which the hydrogen gas in the hydrogen tank 30 is branched by a piping 31a and a piping 31a at a branching portion 31b. The fuel supply pipes (fuel gas supply system components) 31 for supplying the fuel cell stacks 10A and 10B to the two fuel cell stacks 10 and the fuel cell stacks 10A and 10B are discharged through the two systems of pipes 32A and 32B. And a circulation pipe (fuel gas circulation system component) 32 for returning the hydrogen off-gas as an off-gas of the fuel gas to the joining part 32c before the branching of the fuel supply flow path 31 through the joining pipe 32b after joining in the joining part 32a. ing.

  A regulator with a shut-off valve that shuts off or allows the supply of hydrogen gas from the hydrogen tank 30 and adjusts the pressure of the hydrogen gas when permitted to supply fuel gas to the fuel cell stacks 10A and 10B. (Fuel gas supply system components) 33 is provided in the pipe 31a.

  The circulation pipe 32 is provided with a gas-liquid separator (fuel gas circulation system component) 34 in the pipe 32b in order to supply the hydrogen off-gas discharged from the fuel cell stacks 10A and 10B to the fuel cell stacks 10A and 10B again. It has been. The gas / liquid separator 34 separates the gas / liquid of the hydrogen off gas discharged from the fuel cell stacks 10A and 10B, and specifically recovers moisture from the hydrogen off gas.

  A discharge pipe (fuel gas circulation system component) 35 is connected to the gas-liquid separator 34, and a discharge valve (fuel gas circulation system component, exhaust valve) 36 is provided in the discharge pipe 35. ing. The discharge valve 36 operates in response to a command from a control device (not shown), whereby moisture collected by the gas-liquid separator 34 and hydrogen off-gas containing impurities in the circulation flow path 32 are discharged via a discharge pipe 35. It is discharged (purged) to the outside.

  The circulation pipe 32 sucks and pressurizes the hydrogen off-gas in the circulation pipe 32 discharged from the fuel cell stacks 10A and 10B, discharges it to the fuel supply pipe 31 side, and is discharged from the fuel cell stacks 10A and 10B. A circulation electric pump (fuel gas circulation system component) 37 for adjusting gas circulation is provided.

  As shown in FIG. 2, the fuel cell stacks 10 </ b> A and 10 </ b> B are configured by stacking a required number of single cells 40 that receive a reaction gas and generate electric power through an electrochemical reaction. Are arranged in parallel, and are sandwiched between a pair of end plates 41 and 42 that are common to these and disposed at both ends in the stacking direction. The end plates 41 and 42 are connected to each other by a tension plate (not shown).

  The fuel cell stacks 10 </ b> A and 10 </ b> B sandwiched between the end plates 41 and 42 are stored in the stack case 43. Thus, the fuel cell stacks 10A and 10B are installed in the vehicle body in a posture aligned in the horizontal direction in the state of being accommodated in the stack case 43, and will be described below in the posture at the time of installation.

  Since the pair of end plates 41 and 42 described above are common to the plurality of fuel cell stacks 10A and 10B, they have a substantially rectangular shape that is long in the lateral direction. As shown in FIG. A circulation pipe 32, a circulation electric pump 37, a gas-liquid separator 34, a discharge valve 36, and a discharge pipe 35, which are fuel gas circulation system components, are disposed, and a fuel gas supply system component is provided with a shut-off valve. A regulator 33 is also arranged.

  Specifically, first, the circulation electric pump 37 is attached to the end plate 41. The circulation electric pump 37 has an electric motor unit 50 that receives electric power and generates a rotational driving force, and a pump rotor unit 51 that rotates by the driving force of the electric motor unit 50 to suck and discharge gas. The electric motor part 50 and the pump rotor part 51 are arranged in parallel in this direction with their rotational axis directions aligned with each other, thereby forming a long shape in the rotational axis direction.

  The circulation electric pump 37 has a length that is approximately half of the length of the end plate 41, the length direction of the circulation electric pump 37 is along the length direction of the end plate 41, and the electric motor unit 50 is long. A pump rotor portion 51 that is located on one end side in the direction and is heavier than the electric motor portion 50 and has a large vibration is located on the center side of the end plate 41.

  As a result, the circulating electric pump 37 is arranged to be biased to one side in the length direction of the end plate 41 and is also slightly biased to the upper side. The circulation electric pump 37 has a heavy center on the center side of the end plate 41 by disposing the heavy pump rotor portion 51 on the center side of the end plate 41.

  Here, the circulating electric pump 37 is provided with two upper and lower mounting seats 53 and 54 on the heavy pump rotor 51 side, and one lower mounting seat on the lighter electric motor 50 side. 55 is provided and is bolted to the end plate 41 with three points by these three mounting seats 53 to 55. Further, the pump rotor portion 51 is provided with a suction port 56 for sucking gas from the outside facing downward, and a discharge port 57 for discharging the gas to the outside facing upward.

  On the outer peripheral surface of the cylindrical electric motor portion 50 of the circulation electric pump 37, a motor temperature detection thermistor 58 as a component thereof is located below the end position of the electric motor portion 50 that is farthest from the end plate 41. It is attached.

  On the lower side of the circulation electric pump 37 of the end plate 41, a regulator 33 with a shut-off valve, which is an electrical component, is attached. The regulator 33 with a shut-off valve is provided with a shut-off valve section 60 that blocks or allows the passage of gas and a regulator section 61 that adjusts the pressure of the gas after passing through the shut-off valve section 60. It has a long shape in the direction in which the shutoff valve portion 60 and the regulator portion 61 are juxtaposed.

  The length of the regulator 33 with the shut-off valve is slightly shorter than the length of the electric motor portion 50 of the circulation electric pump 37, and the length direction thereof is along the length direction of the end plate 41, and the electric motor portion. 50 and the end plate 41 are arranged so as to be biased to one side in the length direction so that the positions in the length direction are aligned with each other.

  In addition, the regulator 33 with the shut-off valve is attached to the end plate 41 with the shut-off valve portion 60 on the outside and the regulator portion 61 on the inside, and the introduction port 62 through which gas is introduced from outside is provided on the shut-off valve portion 60. A lead-out port 63 is provided in the lower part and directed downward, and is led upward in the upper part of the regulator part 61 so as to lead the gas that has passed through the shutoff valve part 60 and the regulator part 61 to the outside. Furthermore, the shut-off valve portion 60 and the regulator portion 61 are provided with connector portions 64 and 65 for electrical connection, respectively.

  The regulator 33 with the shut-off valve as a whole is disposed closer to the end plate 41 than the end position farthest from the end plate 41 of the electric motor unit 50. As a result, the regulator 33 with the shut-off valve is used for electrical connection. The connector parts 64 and 65 are also covered with the electric motor part 50 on the upper side.

  A gas-liquid separator 34 is attached in parallel with the regulator 33 with the shutoff valve in the length direction of the end plate 41 below the pump rotor portion 51 of the circulating electric pump 37 of the end plate 41. In the gas-liquid separator 34, an introduction port 67 through which gas is introduced from the outside is provided in this direction on the side opposite to the regulator 33 with the shut-off valve, and an outlet port 68 for leading the gas to the outside. However, it is provided in the side part by the side of the regulator 33 with a shut-off valve toward this direction.

  The hydrogen-off gas discharged from the fuel cell stacks 10A and 10B is guided to the side of the gas-liquid separator 34 opposite to the regulator 33 with the shut-off valve and to the substantially central position in the length direction of the end plate 41. The outlet part 69 after the joining of the pipes 32A and 32B shown in FIG. 6 is provided, and the hydrogen off-gas is led to the outlet part 69 at the side part on the gas-liquid separator 34 side toward the gas-liquid separator 34 side. A lead-out port 66 is provided.

  A discharge valve 36 is attached immediately below the gas-liquid separator 34 of the end plate 41. The discharge valve 36 is connected to the gas-liquid separator 34 at the upper part, and an exhaust port 70 for discharging gas to the outside when purging moisture and hydrogen off-gas from the gas-liquid separator 34 faces downward at the lower part. Is provided. The gas-liquid separator 34 and the discharge valve 36 are also arranged closer to the end plate 41 than the end portion of the pump rotor portion 51 farthest from the end plate 41, and the upper side is covered with the pump rotor portion 51. .

  Supply ports 71A and 71B for individually supplying hydrogen gas to the fuel cell stacks 10A and 10B are provided at the upper end positions of both end portions of the end plate 41 in the length direction.

  And the piping part 80 which connects the hydrogen tank 30 and the regulator 33 with a cutoff valve among the piping 31a before the branch of the fuel supply piping 31 is connected to the inlet 62 of the regulator 33 with a cutoff valve, and the cutoff valve among the piping 31a. The piping part 81 which connects the attached regulator 33 and the junction part 32c is connected to the outlet 63 and the junction part 32c of the regulator 33 with the shut-off valve. Furthermore, the junction part 32c and the branch part 31b are connected by the pipe part 82 of the pipe 31a.

  Further, a pipe 31A connecting the branch part 31b and the fuel cell stack 10A is connected to the branch part 31b and the supply port 71A, and a pipe 31B connecting the branch part 31b and the fuel cell stack 10B is connected to the branch part 31b and the supply port. 71B. Here, the piping 31 </ b> A and the piping 31 </ b> B have an equal length so that the hydrogen gas can be evenly distributed, and as a result, the branch portion 31 b is disposed at the approximate center in the length direction of the end plate 41.

  In addition, a pipe 83 connecting the outlet 69 and the gas-liquid separator 34 in the pipe 32 b after the circulation pipe 32 is joined is connected to the outlet 66 of the outlet 69 and the inlet 67 of the gas-liquid separator 34. In the pipe 32 b, a pipe portion 84 connecting the gas-liquid separator 34 and the circulation electric pump 37 is connected to the outlet 68 of the gas-liquid separator 34 and the suction port 56 of the circulation electric pump 37. .

  Further, a pipe portion 85 connecting the circulation electric pump 37 and the fuel supply pipe 31 in the pipe 32b is connected to the discharge port 57 and the junction portion 32c of the circulation electric pump 37. Further, a discharge pipe 35 is connected to a discharge port 70 of the discharge valve 36.

  As described above, the hydrogen gas supplied from the hydrogen tank 30 is introduced from the piping unit 80 to the branching unit 31b via the regulator 33 with the shut-off valve, the piping unit 81, the merging unit 32c, and the piping unit 82, and the branching unit 31b. Thus, the flow is divided into the pipes 31A and 31B and distributed to the fuel cell stacks 10A and 10B.

  Further, the hydrogen off-gas from the fuel cell stacks 10A and 10B is introduced from the outlet 69 into the junction 32c through the pipe 83, the gas-liquid separator 34, the pipe 84, the circulating electric pump 37, and the pipe 85. The hydrogen gas supplied from the hydrogen tank 30 merges, is introduced into the branch part 31b via the pipe part 82, and is distributed again to the fuel cell stacks 10A and 10B.

  Here, the regulator 33 with the shut-off valve, the circulation electric pump 37, the gas-liquid separator 34, the discharge valve 36, and the piping portions 80 to 85 are attached to the end plate 41 in advance and modularized. The battery stacks 10A and 10B and the end plate 42 are assembled.

  The regulator 33 with the shut-off valve, the circulation electric pump 37, the gas-liquid separator 34, and the discharge valve 36 are housed in the stack case 43. Of these, the pump rotor portion 51 of the circulation electric pump 37 is included. The end surface 51 a opposite to the end plate 41 is farthest from the end plate 41, and a predetermined insulation distance X is secured between the end surface 51 a of the pump rotor portion 51 and the stack case 43. Yes. In other words, the components are arranged so that the gap with the stack case 43 is not smaller than the insulation distance X.

  In the circulation electric pump 37, the thermistor 58 for detecting the motor temperature is attached to the lower side of the end portion of the substantially cylindrical electric motor unit 50 that is farthest from the end plate 41. It can be brought close to the end plate 41, and the distance between the motor temperature detecting thermistor 58 and the stack case 43 is also secured.

  According to the fuel cell system 1 described above, the end plate 41 that fixes the fuel cell stacks 10A and 10B is provided with the circulation electric pump 37, the gas-liquid separator 34, and the discharge valve 36, which are fuel gas circulation system components. Since it is fixed, the piping length of the piping portion 85 that connects the fuel supply piping 31 to the fuel cell stacks 10A and 10B and the circulating electric pump 37 can be shortened, and the outlet side of the fuel cell stacks 10A and 10B And the piping length of the piping part 83 which connects the gas-liquid separator 34 can be shortened.

  Moreover, by providing the pump rotor portion 51 of the circulating electric pump 37 on the center side of the end plate 41, the branch point 31b provided on the center side of the end plate 41 and the discharge port 57 can be brought close to each other. Moreover, the length of the piping part 85 can be further shortened.

  By shortening the piping length as described above, the pressure loss can be reduced and the heat efficiency and the pump efficiency can be improved, so that the power consumption of the circulating electric pump 37 can be reduced. Moreover, since the entire heat capacity can be reduced by shortening the pipe length, pipe freezing can be suppressed.

  Furthermore, since the amount of hydrogen remaining when the system is stopped can be reduced by shortening the piping length, the amount of cross leak in the fuel cell stacks 10A and 10B can be reduced. In addition, since the amount of hydrogen in the pipe can be reduced by shortening the pipe length, the amount of hydrogen pushed in at the time of system startup can be reduced, and the pressurization time can be shortened.

  Further, since the regulator 33 with a shut-off valve, which is an electrical component, is disposed below the circulation electric pump 37, the connector portions 64 and 65 for allowing the condensation of the fuel cell stacks 10A and 10B to electrically connect the regulator 33 with the shut-off valve. Can be suppressed, and the occurrence of electrical shorts can be suppressed.

  In addition, the circulation electric pump 37 includes an electric motor unit 50 that rotates electrically, and a pump rotor unit 51 that rotates by the driving force of the electric motor unit 50 to suck and discharge fuel off-gas. Since the pump rotor portion 51 is disposed on the center side of the end plate 41 with respect to the portion 50, a weight balance can be achieved and vibration of the circulating electric pump 37 can be suppressed.

  Further, since the suction port 56 is provided in the lower part of the pump rotor portion 51 of the circulation electric pump 37, the discharge port 57 is provided in the upper part, and the gas-liquid separator 34 is provided below the suction port 56, the circulation electric pump 37. In addition, water can be dropped to the gas-liquid separator 34 without retaining water in the pipe portion 84. Thereby, the piping blockage by freezing can be prevented.

  Further, when the circulating electric pump 37 is attached to the end plate 41, the pump rotor 51 side which is heavy and has large vibrations is bolted with the two mounting seats 53 and 54, and the electric motor is light in weight and small in vibrations. Since the part 50 side is bolted with the mounting seat part 55 at one place, the number of parts can be reduced and it can be fixed efficiently.

  Note that the pump rotor portion 51 of the circulating electric pump 37 is located on the center side of the end plate 41 even when the bank is mounted in the reverse direction in which the circulating electric pump 37 is mounted to the left and right in contrast to the bank mounting in which the circulating electric pump 37 is mounted as described above. With respect to the above, the circulation electric pump 37, the regulator 33 with the shut-off valve, the circulation electric pump 37, the gas-liquid separator 34, the discharge valve 36, and the like are all configured mirror-symmetrically.

  Further, the regulator 33 with the shutoff valve may be replaced with an injector that adjusts the upstream gas state (flow rate, pressure, temperature, molar concentration, etc.) and supplies it to the downstream side.

1 is a configuration diagram of a fuel cell system according to an embodiment of the present invention. It is a top view of the stack case of the fuel cell system concerning one embodiment of the present invention, and its inside. BRIEF DESCRIPTION OF THE DRAWINGS The end plate of a fuel cell system which concerns on one Embodiment of this invention, a fuel gas circulation system component, etc. are shown, (a) is a front view, (b) is a side view.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Fuel cell system, 3 ... Fuel gas supply system, 10A, 10B ... Fuel cell stack, 31 ... Fuel supply piping (fuel gas supply system component), 32 ... Circulation piping (fuel gas circulation system component), 33 ... Regulator with shut-off valve (fuel gas supply system components, electrical components), 34 ... gas-liquid separator (fuel gas circulation system components), 35 ... discharge piping (fuel gas circulation system components), 36 ... discharge valve (fuel) Gas circulation system components, exhaust valves), 37 ... circulation electric pump (fuel gas circulation system components), 41 ... end plate, 50 ... electric motor part, 51 ... pump rotor part.

Claims (5)

A plurality of cells that generate power by electrochemical reaction of fuel gas and oxidizing gas, and a fuel cell stack sandwiched between a pair of end plates disposed at both ends in the stacking direction of the cells;
Fuel gas supply system components for supplying fuel gas to the fuel cell stack;
A fuel gas circulation system component that again supplies the fuel off-gas discharged from the fuel cell stack to the fuel cell stack, and a fuel cell system comprising:
A circulating electric pump having a motor unit that generates a rotational driving force and a rotor unit that rotates by the driving force of the motor unit to suck and discharge gas, and adjusts the circulation of the gas discharged from the fuel cell stack; ,
A merging portion where the fuel gas and the fuel off gas merge;
A pipe connecting the junction and a discharge port provided in the rotor of the circulating electric pump;
A branch portion provided on the center side of the end plate, for branching the fuel gas introduced from the merging portion and supplying the branched fuel gas to the fuel cell stack,
The fuel cell system which fixes the rotor part side of the said circulation electric pump to the center side of the said end plate.   2. The fuel cell system according to claim 1, wherein the fuel gas circulation system component is a gas-liquid separator that separates a gas-liquid of a fuel off-gas discharged from the fuel cell stack.   2. The fuel cell system according to claim 1, wherein the fuel gas circulation system component is an exhaust valve that exhausts the fuel off-gas discharged from the fuel cell stack to the outside. The fuel cell system according to claim 1 , wherein an electrical component is disposed below the circulating electric pump.   2. The fuel cell stack and a stack case for storing the fuel gas circulation system component, and a predetermined insulation distance is secured between the stack case and the fuel gas circulation system component. Fuel cell system.

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