JP2007172868A - Vehicle mounted fuel cell system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel cell system which does not require a large strength of a fuel tank and also does not require a special filling device for filling a fuel into the fuel tank. <P>SOLUTION: The fuel cell system comprises at least one structure which constitutes a vehicle body and is used as a fuel tank to store a fuel gas, a fuel cell stack formed by laminating unit cells, and a fuel supply path for supplying the fuel gas discharged from the structure to the fuel cell stack. Since the structure to constitute the vehicle body is used as the fuel tank for storing the fuel gas, the storage quantity of the fuel gas in the fuel tank can be increased. Since it is not necessary to store a high pressure fuel gas in the fuel tank, it is not necessary to increase the strength of the fuel tank. As the fuel tank can be made small in size and light in weight, the cost of the vehicle can be lowered to that extent. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an in-vehicle fuel cell system.

  Conventionally, in a vehicle equipped with a fuel cell (vehicle equipped with a fuel cell), electric power generated by the stacked fuel cell is supplied to the drive motor as a current, and torque is generated by driving the drive motor. I have to.

  For this purpose, an in-vehicle fuel cell system is provided in the vehicle, and the in-vehicle fuel cell system is a fuel tank in which hydrogen gas as high-pressure fuel is stored, hydrogen gas is supplied from the fuel tank, and air is supplied. A fuel cell stack constituting the fuel cell, a condenser for condensing the steam in the mixed flow composed of air, steam and water discharged from the fuel cell stack. The fuel cell stack includes a supply manifold for supplying air to the upper end portion and a discharge manifold for discharging the mixed flow to the lower end portion.

  In the fuel cell stack, a module is accommodated in a stack case. In the module, hydrogen of the hydrogen gas and oxygen in the air are reacted to generate water, and current is generated along with the reaction. Is generated. For this purpose, the module is composed of an assembly formed by stacking a plurality of unit cells constituting elements of a fuel cell and electrically connecting them in series, and each unit cell sandwiches an electrolyte membrane. The membrane electrode assembly (MEA) formed by disposing the air electrode and the fuel electrode in FIG. 5 and the membrane electrode assembly of the adjacent unit cell are separated from each other and faced to the air electrode. A separator is provided that forms a fuel flow path with the flow path facing the fuel electrode.

  However, in the conventional vehicle, since high-pressure hydrogen gas is stored in the fuel tank, it is necessary to increase the strength of the fuel tank. In this case, the fuel tank becomes larger and heavier. Therefore, it is conceivable to form the fuel tank with a light material, but the cost of the vehicle is increased accordingly.

  In addition, in order to fill the fuel tank with hydrogen gas at a high pressure, it is necessary to use a special filling device, which increases the cost of the vehicle.

  The present invention solves the problems of the conventional vehicle, and it is not necessary to increase the strength of the fuel tank, and it is not necessary to use a special filling device to fill the fuel tank with the fuel. It is an object of the present invention to provide an on-vehicle fuel cell system capable of reducing the fuel consumption.

  Therefore, in the in-vehicle fuel cell system according to the present invention, the fuel cell stack formed by stacking at least one structure used as a fuel tank for constituting a vehicle body and storing fuel gas, and a unit cell. And a fuel supply path for supplying the fuel gas discharged from the structure to the fuel cell stack.

  In another in-vehicle fuel cell system of the present invention, each of the structures further includes a tank body divided into a plurality of compartments.

  In still another in-vehicle fuel cell system according to the present invention, a liner that does not transmit fuel gas is formed on the inner peripheral surface of each compartment.

  In still another in-vehicle fuel cell system of the present invention, an on-off valve is further provided for each of the compartments.

  According to the present invention, in an in-vehicle fuel cell system, a fuel cell stack formed by laminating unit cells and at least one structure used as a fuel tank for constituting a vehicle body and storing fuel gas And a fuel supply path for supplying the fuel gas discharged from the structure to the fuel cell stack.

  In this case, since the structure constituting the vehicle body is used as a fuel tank for storing the fuel gas, the amount of fuel gas stored in the fuel tank can be increased.

  Therefore, it is not necessary to store the high-pressure fuel gas in the fuel tank, so that it is not necessary to increase the strength of the fuel tank. As a result, the fuel tank can be reduced in size and lightened, so that the cost of the vehicle can be reduced accordingly.

  In addition, since the fuel tank can be filled with the fuel gas at a low pressure, it is not necessary to use a special filling device, and the cost of the vehicle can be reduced accordingly.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 2 is a conceptual diagram showing an in-vehicle fuel cell system according to an embodiment of the present invention.

  In the figure, reference numeral 11 denotes a stacked fuel cell, and in this embodiment, a fuel cell stack constituting a polymer electrolyte fuel cell (PEFC). The fuel cell stack 11 is a passenger car, bus, truck, passenger car. Vehicles such as carts and luggage carts, and in this embodiment, are mounted as energy supply sources on predetermined wheels among the wheels of a passenger car. In this case, the current generated by the fuel cell stack 11 is supplied to a drive motor (not shown), and each wheel is rotated by driving the drive motor. Therefore, it is preferable that the fuel cell stack 11 is disposed adjacent to the drive motor and mounted on at least the drive wheel among the wheels.

  Reference numeral 14 denotes a hydrogen gas supply system as a fuel and a fuel supply system for supplying hydrogen gas as a fuel gas to the fuel cell stack 11, and 22 denotes a medium to the fuel cell stack 11. In addition, it is a manifold for supplying air as an oxidant and discharging a mixed flow of air, steam and water from the fuel cell stack 11. The fuel cell stack 11, the hydrogen gas supply system 14, and the manifold 22 constitute an in-vehicle fuel cell system.

  In the present embodiment, a polymer electrolyte fuel cell is used as the fuel cell used in the fuel cell stack 11, but instead of the polymer electrolyte fuel cell, phosphoric acid is used. A type fuel cell (PAFC), a solid oxide type fuel cell (SOFC), a hydrazine type fuel cell, a direct methanol type fuel cell (DMFC) or the like can be used.

  The fuel cell stack 11 includes a plurality of modules (not shown) and an insulator formed of an insulating material and disposed between the modules. The insulators constitute a pair of illustrations that constitute terminals of the fuel cell stack 11. With a terminal that is not.

  Meanwhile, in each of the modules, hydrogen in the hydrogen gas supplied by the hydrogen gas supply system 14 and oxygen contained in the air supplied through the manifold 22 are reacted to generate water, A current is generated with the reaction. For this purpose, the module is composed of an assembly formed by stacking a plurality of thin membrane unit cells constituting elements of the fuel cell stack 11 and electrically connecting them in series.

  Each unit cell is made of a solid polymer, and in the present embodiment, an air electrode composed of a diffusion layer and a fuel electrode composed of a reaction layer with an electrolyte membrane serving as a solid electrolyte that permeates ions, hydrogen ions in this embodiment. The membrane electrode assembly formed by disposing the (hydrogen electrode) and the membrane electrode assembly of the adjacent unit cell are separated from each other, and the air channel is faced to the air electrode. A separator that forms a fuel flow path facing the fuel electrode is provided, and the air flow path and the manifold 22 are communicated with each other.

  In order to promote the reaction between hydrogen and oxygen, the surface of the air electrode and the fuel electrode in contact with the electrolyte membrane contains a certain amount of a paste material obtained by mixing a platinum-based catalyst and a solid polymer with carbon. The catalyst layer is formed by uniformly dispersing in thickness. Note that an oxygen electrode may be used instead of the air electrode, and pure oxygen as a medium and as an oxidant may be supplied to the fuel cell stack 11.

  The entire surface of the separator facing the fuel electrode is adhered and sealed to the adjacent membrane electrode assembly with an adhesive. Therefore, a plurality of protrusions are formed inside the sealed portion so as to protrude in a matrix, and a plurality of horizontal fuel flow paths for supplying hydrogen gas to the fuel electrode are formed between the protrusions. The Reference numeral 71 denotes a voltage sensor (V) as a plurality of voltage detectors for detecting an electromotive voltage of the fuel cell stack 11.

  The hydrogen gas supply system 14 is connected to a fuel tank 41 as a fuel supply device in which relatively low-pressure hydrogen gas is stored, and the hydrogen gas discharged from the fuel tank 41 is supplied to the fuel cell stack 11. A first fuel supply path 51 for supplying to the fuel cell, a second fuel supply path 52 connecting the first fuel supply path 51 and the fuel cell stack 11, and the second fuel supply path 52 A fuel return path 53 that is formed in parallel, connects between the first fuel supply path 51 and the fuel cell stack 11 and returns hydrogen gas, and is connected to the fuel return path 53 and discharges hydrogen gas. A discharge path 54 and the like are provided.

  Then, the first pressure for detecting the pressure (primary pressure) of the hydrogen gas discharged to the first fuel supply path 51 from the fuel tank 41 side to the fuel cell stack 11 side in the first fuel supply path 51. A hydrogen gas pressure sensor (P) 42 as a detector, a pressure regulating valve 43 as a fuel supply pressure adjusting unit for adjusting the pressure of the hydrogen gas discharged to the first fuel supply path 51, and hydrogen to the fuel cell stack 11 An on-off valve 44 as a fuel supply amount adjusting unit for adjusting the gas supply amount, and a second that is adjusted by the on-off valve 44 and detects the pressure (secondary pressure) of hydrogen gas immediately before being supplied to the fuel cell stack 11. A hydrogen gas pressure sensor (P) 45 is disposed as a pressure detector.

  The on-off valve 44 not only adjusts the amount of hydrogen gas supplied, but also supplies or shuts off the hydrogen gas to the fuel cell stack 11. In addition, although the said pressure regulation valve 43 is arrange | positioned in order to make the pressure of hydrogen gas low, two or more pressure regulation valves can be arrange | positioned as needed.

  The fuel return path 53 is provided with a hydrogen concentration sensor (C) 46, a suction pump 47, and a check valve 48 as a fuel concentration detector from the fuel cell stack 11 side to the fuel tank 41 side. The stop valve 48 and the first fuel supply path 51 are connected. The check valve 48 allows hydrogen gas to flow from the suction pump 47 side to the hydrogen gas pressure sensor 45 side, and prevents hydrogen gas from flowing from the hydrogen gas pressure sensor 45 side to the suction pump 47 side.

  The fuel discharge path 54 is connected between the suction pump 47 and the check valve 48 in the fuel return path 53, and the check valve 55 and the discharge are sequentially connected to the fuel discharge path 54 from the fuel return path 53 side. An electromagnetic valve 56 is provided. The check valve 55 allows hydrogen gas to flow from the suction pump 47 side to the discharge electromagnetic valve 56 side, and prevents hydrogen gas from flowing from the discharge electromagnetic valve 56 side to the suction pump 47 side.

  By the way, if high-pressure hydrogen gas is stored in the fuel tank 41, it is necessary to increase the strength of the fuel tank 41, and the fuel tank 41 becomes larger and heavier. Therefore, the capacity of the fuel tank 41 is increased, and hydrogen gas of 10 [atm] is stored in the fuel tank 41 at a relatively low pressure in the present embodiment.

  Therefore, in the present embodiment, each structural body constituting the vehicle body is used as the fuel tank 41.

  FIG. 1 is a conceptual diagram of a vehicle in an embodiment of the present invention, and FIG. 3 is a schematic diagram of the vehicle in an embodiment of the present invention.

  In the figure, 13 is a platform constituting the floor of the vehicle, 15 to 18 are doors, 19 is a roof, 21 is a hood hood, 23 is a trunk lid, 24 is a fender, the platform 13, roof 19 and doors 15 to 15 are shown. 18, the hood hood 21, the trunk lid 23, the fender 24, and the like constitute a structure mi (i = 1, 2,...), And each structure mi is used as a fuel tank 41 (FIG. 2). Further, whj (j = 1 to 4) is a wheel (in FIG. 1, only three wheels whj (j = 1 to 3) of the four wheels whj are shown).

  Next, each structure mi will be described.

  FIG. 4 is a perspective view showing an arrangement state of the structure in the embodiment of the present invention, and FIG. 5 is a cross-sectional view of the tank main body in the embodiment of the present invention.

  In the figure, 73 is an outer plate disposed on the outer surface of the vehicle, 74 is a tank body disposed inside the outer plate 73, and the tank body 74 has a plurality of compartments rk (k = 1). And a liner 78 made of a material that does not transmit hydrogen is formed on the inner peripheral surface of each compartment rk. The liner 78 is formed by coating a rubber film with a metal film by vapor deposition or using a resin such as nylon (registered trademark). Reference numeral 51 denotes a first fuel supply path, and a branch pipe pm (m = 1, 2,...) Branched between the first fuel supply path 51 and the tank body 74 for each compartment rk. ..), On-off valves vn (n = 1, 2,...) And manifolds 76 disposed in the respective branch pipes pm.

  In this case, since each section chamber rk is formed independently, even if fuel leakage occurs in a predetermined partition chamber for some reason, closing the corresponding on-off valve vn does not affect other partition chambers. It will not reach.

By the way, when the platform 13 (FIG. 1) is used as the structure, the platform 13 has a double structure. For example, the entire platform 13 is a fuel tank 41, and the average height of the double structure portion is 10 cm. ], The volume of the fuel tank 41 can be reduced to about 0.8 [m ³ ] in the passenger car. In the present embodiment, since the pressure of the hydrogen gas stored in the fuel tank 41 is 10 [atm], the platform 13 can store about 8 [m ³ ] of hydrogen gas.

  Therefore, a sufficient amount of hydrogen gas can be stored in the fuel tank 41 by using each structural body mi of the vehicle as the fuel tank 41. Table 1 shows the results of calculating the storage amount when hydrogen gas was stored under various conditions.

When the structure of only the lower part of the vehicle is used as the fuel tank 41, the effective area of the fuel tank 41 is 8 [m ² ], and when the thickness of each structure is 10 [cm], the volume of the fuel tank 41 is increased. Becomes 0.8 [m ³ ]. At this time, when the pressure of the hydrogen gas is set to 10 [atm], the storage amount becomes 8 [m ³ ].

Further, when the structure only in the lower part of the vehicle is used as the fuel tank 41, the effective area of the fuel tank 41 is 8 [m ² ], and when the thickness of each structure is 20 [cm], the fuel tank 41 The volume of is 1.6 [m ³ ]. At this time, if the pressure of the hydrogen gas is 10 [atm], the storage amount is 16 [m ³ ].

When the structure of the entire vehicle body is used as the fuel tank 41, the effective area of the fuel tank 41 is 20 [m ² ], and when the thickness of each structure is 20 [cm], the fuel tank 41 The volume of is 4 [m ³ ]. At this time, if the pressure of the hydrogen gas is 10 [atm], the storage amount is 40 [m ³ ].

  Thus, by using the vehicle structure mi as the fuel tank 41, the amount of hydrogen gas stored in the fuel tank 41 can be increased.

  Therefore, it is not necessary to store high-pressure hydrogen gas in the fuel tank 41, and therefore it is not necessary to increase the strength of the fuel tank 41. As a result, the fuel tank 41 can be reduced in size and lightened, so that the cost of the vehicle can be reduced accordingly.

  In addition, since the fuel tank 41 can be filled with hydrogen gas at a low pressure, there is no need to use a special filling device, and the cost of the vehicle can be reduced accordingly.

It is a conceptual diagram of the vehicle in embodiment of this invention. It is a conceptual diagram which shows the vehicle-mounted fuel cell system in embodiment of this invention. It is the schematic of the vehicle in embodiment of this invention. It is a perspective view which shows the arrangement | positioning state of the structure in embodiment of this invention. It is sectional drawing of the tank main body in embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Fuel cell stack 14 Hydrogen gas supply system 22 Manifold 41 Fuel tank 51, 52 1st, 2nd fuel supply path 74 Tank main body 78 Liner mi structure rk, r1-r4 Compartment chamber vn, v1-v4 On-off valve

Claims (4)

(A) at least one structure constituting a vehicle body and used as a fuel tank for storing fuel gas;
(B) a fuel cell stack formed by stacking unit cells;
(C) An in-vehicle fuel cell system comprising a fuel supply path for supplying fuel gas discharged from the structure to a fuel cell stack.   The in-vehicle fuel cell system according to claim 1, wherein each structure has a tank body divided into a plurality of compartments.   The in-vehicle fuel cell system according to claim 2, wherein a liner that does not transmit fuel gas is formed on an inner peripheral surface of each compartment. The on-vehicle fuel cell system according to claim 2, wherein an on-off valve is provided for each of the compartments.

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