JP4910365B2 - Fuel cell stack, fuel cell system, and mobile body equipped with the system - Google Patents

Description

  The present invention relates to a fuel cell stack, a fuel cell system, and a moving body equipped with the system.

In recent years, a fuel cell vehicle has been disclosed in which a high voltage relay is provided on one end surface in the cell stacking direction of a fuel cell stack and a cooling medium flow path or a reaction gas flow path is connected to the other end face (for example, , See Patent Document 1). As an advantage of providing a high voltage relay integrally with the fuel cell stack as in this fuel cell vehicle, the distance from the output terminal of the fuel cell stack to the high voltage relay is shortened, so that the high voltage state is established when the relay is cut off. There are times when there are fewer parts.
JP 2002-367666 A

  However, in the case of a stack having a conventional structure, if the end face in the cell stacking direction becomes smaller, the reaction gas pipe (for example, hydrogen supply pipe and discharge pipe, oxidant supply pipe and discharge pipe), refrigerant pipe, stack load mechanism, etc. It becomes difficult to efficiently arrange or connect components necessary for generating power from the fuel cell in a narrow space. In particular, high voltage relays are difficult to arrange because there is a limit to miniaturization due to the amount of power handled by the relays. In addition, the relay may interfere with other parts such as piping connected to the stack and other parts around the stack.

  Accordingly, an object of the present invention is to provide a fuel cell stack, a fuel cell system, and a mobile body equipped with the system having a structure capable of realizing further miniaturization.

  According to the first aspect of the present invention, there is provided a stack main body in which a plurality of cells are stacked, a frame surrounding the stack main body, and both ends of the frame, and a space inside the frame. And a relay connected to a power output terminal provided in the stack body, wherein the relay is provided above or below the stack body. It is characterized by that.

  According to a second aspect of the present invention, in the fuel cell stack according to the first aspect, the relay is disposed on an upper surface or a lower surface outside the frame, or a ceiling surface or a bottom surface inside the frame. It is a feature.

  The invention according to claim 3 is the fuel cell stack according to claim 1 or 2, further comprising a reaction gas supply device for supplying a reaction gas to at least one end of the stack body in the cell stacking direction. .

  The fuel cell stack according to the present invention, which is characterized by the arrangement of relays, is characteristic in the following points with respect to the conventional structure arranged on the side surface of the stack. That is, when connecting gas piping, refrigerant piping, or the like to the fuel cell stack, or when these are arranged around the fuel cell stack, it can be more advantageous than the conventional structure. There is an advantage that it is easy to realize. In addition, in a situation where the fuel cell system including the fuel cell stack or the mobile body on which the fuel cell stack is mounted is increasingly miniaturized and densified, while taking a structure in which the electric system and the liquid system are separated, Although there is a possibility that a situation or a request for arranging the relay in a narrow space with high density may occur, according to the present invention, it becomes possible to respond to such a request in response to such a situation. In addition, when further downsizing and higher density occur, the fuel cell stack and other members such as pipes arranged around the fuel cell stack may interfere with each other during vibration, for example. According to the present invention that facilitates connection and arrangement of the above, such a situation can be suppressed. In addition, realization of further miniaturization and higher density leads to effective use of dead space.

  According to a fourth aspect of the present invention, there is provided a fuel cell system including the fuel cell stack and a reaction gas supply device that supplies a reaction gas to the stack body.

  Furthermore, the moving body according to claim 5 includes the fuel cell system, a motor that receives power supply from the stack body and generates a moving driving force of the moving body, and the stack body via the relay. And a power control device that controls supply of power generated by the stack body to the motor.

  According to the present invention, it is possible to further reduce the size of the fuel cell stack, and it is also advantageous in terms of connection or arrangement of gas piping and refrigerant piping.

  Hereinafter, the configuration of the present invention will be described in detail based on an example of an embodiment shown in the drawings.

  1 to 4 show an embodiment of the present invention. As shown in FIG. 2, the fuel cell stack 1 of the present embodiment includes a stack body 3 in which a plurality of cells 2 that are basic units are stacked, and a frame 5 that houses the stack body 3 inside. Further, the frame 5 of the present embodiment is an extruded metal cylindrical body, and has a rectangular cross section (cross section perpendicular to the longitudinal direction). Since tension acts on the frame 5 as will be described later, the wall portions on the top and bottom and both sides of the frame 5 are formed thick in order to exhibit sufficient proof strength against the tension. A resin film (not shown) is formed on the inner surface of the frame 5 for insulation. The inner surface of the frame 5 here means not only the inner surface of the frame but also the surface of the seal portion (for example, the groove 14 into which the rubber seal ring is fitted). By coating these seal portions as well, for example, even if dew condensation occurs in the stack body 3, it is possible to maintain an insulating state.

  A terminal plate 7 is disposed at one end of the stack body 3 along the stacking direction of the cells 2, and an insulating plate 8 is disposed outside the terminal plate 7 (see FIG. 2). A terminal plate 7 is disposed at the other end of the stack body 3, an insulating plate 8 is disposed outside the stack plate 3, and a pressure plate 9 is disposed outside the terminal plate 7. Each terminal plate 7 is provided with an output terminal 6.

  The stack body 3 is accommodated inside the frame 5 such that the stacking direction of the cells 2 coincides with the longitudinal direction of the frame 5. An air gap is provided between the stack body 3 and the inner surface of the frame 5 so that the stack body 3 can be easily placed inside the frame 5.

  As shown in FIG. 2, end plates 10 a and 10 b that define a space inside the frame 5 are fixed to both ends of the frame 5, for example, both end surfaces. The end plates 10 a and 10 b are resin-made plate-like bodies that form a rectangle that matches the cross-sectional shape of the frame 5.

  A plurality of screw holes 12a are provided on both end faces of the frame 5 at intervals along the circumferential direction in order to fix the end plates 10a and 10b (see FIG. 3). Each screw hole 12 a is formed such that the screwing direction coincides with the longitudinal direction of the frame 5. On the other hand, the end plates 10a and 10b are provided with a plurality of through holes 12b so as to match the screw holes 12a (see FIGS. 2 and 3). Bolt screws 13 are respectively screwed into the screw holes 12a and the through holes 12b provided so as to match the positions.

  In addition, endless grooves 14 are formed on both end surfaces of the frame 5 along the circumferential direction of the frame 5 inside the screw holes 12a. A rubber seal ring 15 is fitted in the groove 14. The seal ring 15 is in close contact with the end plates 10a and 10b, thereby sealing between one end surface of the frame 5 and the end plate 10a and between the other end surface of the frame 5 and the end plate 10b. ing.

  The insulating plate 8 disposed on one end face of the stack body 3 abuts on one end plate 10a, and the pressure plate 9 disposed on the other end face of the stack body 3 is separated from the other end plate 10b. (See FIG. 2). A spring box 11 is interposed between the pressure plate 9 and the end plate 10b. The spring box 11 exerts an urging force in a direction to move the pressure plate 9 away from the end plate 10b, and the plurality of cells 2 are fastened by the urging force. The reaction force against the urging force of the spring box 11 is borne by the frame 5, whereby a tension acts on the frame 5 in the longitudinal direction. Even if the length of the stack body 3 in the stacking direction fluctuates due to thermal expansion or a creep phenomenon, the spring box 11 absorbs the fluctuation by the elastic deformation of the spring box 11 itself. In addition, a shim (a plate for adjusting the dimensions) is interposed between the end plate 10b and the spring box 11 as necessary.

  Although not shown in detail, the cell 2 includes an MEA (Membrane-Electrode Assembly) in which an electrolyte membrane made of an ion exchange membrane is sandwiched between a pair of electrodes, and a pair of separators that sandwich the MEA. The base material of each separator is made of carbon or metal and has conductivity.

  The stack body 3 includes an oxidizing gas manifold that supplies an oxidizing gas to the MEA in each cell 2, a hydrogen gas manifold that supplies hydrogen gas as a fuel gas to the MEA in each cell 2, and an oxidizing gas in the MEA. A refrigerant manifold that recovers heat generated by an electrochemical reaction with hydrogen gas is provided separately on an inlet side and an outlet side (however, these manifolds are not shown).

  The end plate 10a disposed at one end of the stack body 3 communicates with each manifold on the inlet side and fluid pipings 16a, 16b, 16e for supplying various fluids to the stack body 3 and each manifold on the outlet side. Fluid pipings 16c, 16d, and 16f for discharging various fluids that have circulated through the stack body 3 are connected. The fluid pipings 16a to 16f in the present embodiment are all made of resin. In the end plate 10a, six through-holes through which the fluid pipes 16a to 16f are inserted are formed in two rows of three, and in the gap between each through-hole and each of the fluid pipes 16a to 16f, For example, sealing members 17a to 17f made of O-rings (however, only 17a to 17c are shown in FIG. 2) are provided.

  Two side walls 5b of the frame 5 are formed with two elongated holes 5d extending in the longitudinal direction of the frame 5 (see FIG. 1). A hydrogen permeable membrane 18 is stretched in each of the elongated holes 5d divided in the upper and lower directions. A seal member (not shown) is disposed in the gap between the long hole 5d and the hydrogen permeable membrane 18. The hydrogen permeable membrane 18 transmits only hydrogen without permeating water, and keeps the hydrogen concentration in the space inside the frame 5 constant. A hydrogen concentration sensor (not shown) is provided in the upper part of the space inside the frame 5. The upper wall 5c of the frame 5 is provided with a through hole (not shown) through which the wiring connected to the hydrogen concentration sensor is passed. The hydrogen concentration sensor constantly monitors the hydrogen concentration in the space inside the frame 5. A seal member (not shown) is disposed between the through hole of the upper wall portion 5c and the wiring of the hydrogen concentration sensor.

  On the outer surface of the upper wall portion 5c of the frame 5, a high voltage case 20 that houses the high voltage relay 25 is disposed close to the other side wall portion 5a. The high voltage case 20 is a rectangular parallelepiped metal casing having one surface opened. A flange 21 projecting outward is formed around the open surface of the high voltage case 20. A plurality of through holes for allowing the bolt screw 22 to pass through are formed in the flange 21 at intervals. On the other hand, the upper wall portion 5c of the frame 5 is provided with a plurality of screw holes so as to match the plurality of through holes. The plurality of screw holes are formed in the thickness direction of the upper wall portion 5c, but are not penetrated. Bolt screws 22 are respectively screwed into the matched through holes and screw holes, whereby the high voltage case 20 is fixed to the upper wall portion 5c. A seal member 23 is disposed between the upper wall portion 5c of the frame 5 and the flange 21 without any gap (see FIG. 2).

  A high voltage relay 25 is built inside the high voltage case 20 attached to the frame 5, and an upper wall portion 5 c of the frame 5 covered with the high voltage case 20 is arranged in the stacking direction of the stack body 3. An output cable Ca connected to the output terminal 6 (+ terminal) provided at one end and an output cable Cb connected to the output terminal 6 (− terminal) provided at the other end of the stack body 3 in the stacking direction. A through hole 5e to be inserted is formed (see FIG. 2). The output cables Ca and Cb inserted through the through hole 5e are connected to the high voltage relay 25 described above.

  The high voltage case 20 is formed with a through hole 26 through which the output cables Ca ′ and Cb ′ connected to the high voltage relay 25 and drawn out of the fuel cell stack 1 are inserted (see FIG. 2). Between the through hole 26 and the output cables Ca ′ and Cb ′, a seal member 27 is disposed to seal the gap between the two. The output cables Ca 'and Cb' are connected to a power control device (not shown) such as a DC / DC converter, an inverter, an inverter for an air compressor, an inverter for a hydrogen pump, an inverter for a coolant pump.

  A cell monitor case 30 for accommodating a cell monitor (not shown), which will be described later, is disposed on the upper surface on the outer side of the frame 5, that is, the outer surface of the upper wall portion 5c, close to the other side wall portion 5b. The cell monitor case 30 is a rectangular parallelepiped metal casing having one surface opened. A flange 31 is formed around the open surface of the cell monitor case 30 so as to project outward. A plurality of through holes for allowing the bolt screws 32 to pass therethrough are formed in the flange 31 at intervals. On the other hand, the upper wall portion 5c of the frame 5 is provided with a plurality of screw holes so as to match the plurality of through holes. The plurality of screw holes are formed in the thickness direction of the upper wall portion 5c, but are not penetrated. Bolt screws 32 are respectively screwed into the matched through holes and screw holes, and thereby the cell monitor case 30 is fixed to the upper wall portion 5c. A seal member (not shown) is also disposed between the upper wall portion 5c of the frame 5 and the flange 31 without a gap.

  Although not shown, a substrate constituting the cell monitor is built inside the cell monitor case 30 attached to the frame 5, and the upper wall portion 5 c of the frame 5 covered with the cell monitor case 30 has a cell monitor case. A through hole through which the terminal passes is provided. A seal member is disposed between the through hole and the cell monitor terminal, and the space inside the cell monitor case 30 and the space inside the frame 5 are isolated from each other. Although the cell monitor substrate is susceptible to changes in temperature and humidity, even if the temperature and humidity of the space inside the frame 5 change due to the separation of these two spaces, the inside of the cell monitor case 30 In such a space, such a change in state is difficult, and the substrate of the cell monitor is kept healthy.

  The cell monitor case 30 is formed with a through-hole through which a wiring connected to the cell monitor substrate is inserted. A seal member is provided between the through hole and the cell monitor wiring to seal the gap between them.

  The reason why the high voltage case 20 and the cell monitor case 30 are separately provided is to avoid the influence of noise from each other because both members generate noise.

  Mounts 40 are provided on the lower edges of the end plates 10 a and 10 b fixed to the frame 5 so as to be interposed between the vehicle body and the fuel cell stack 1 and support the fuel cell stack 1. A total of three mounts 40 are provided, one at the center of the lower edge of the end plate 10a and two at the lower edge of the end plate 10b.

  The fuel cell stack 1 constitutes a fuel cell system together with a reaction gas supply device that supplies a reaction gas such as oxidizing gas and hydrogen gas to the stack body 3 and a refrigerant supply device that supplies a refrigerant to the stack body 3. The fuel cell system includes a drive motor, a reactive gas supply device, a motor for driving a pump used in the refrigerant supply device, and a stack main body that are supplied with electric power from the stack main body 3 to generate a vehicle driving force. 3 is mounted on a vehicle body 41 as a moving body together with a power control device that is connected to the motor 3 via a high-voltage relay 25 and controls the supply of power generated by the stack body 3 to the motor.

  As shown in FIG. 4, the fuel cell stack 1 configured as described above has a cell monitor case 30 and a high-voltage case 20 in a stack accommodation space (or accommodation room R) provided in front of the passenger compartment of the vehicle body 41. The cell monitor case 30 is disposed on the front side of the vehicle body 41, and the high voltage case 20 is disposed on the rear side of the vehicle body 41. The cell monitor case 30 is fixed through three mounts 40.

  Since the fuel cell stack 1 configured as described above is attached to the vehicle body 41 with the surface on which the high voltage relay 25 is attached facing upward, the high voltage relay 25 is not subject to interference with other surrounding components. Since it is avoided, damage is suppressed. Thus, since the high voltage relay 25 is not easily damaged, the risk of a short circuit of the fuel cell can be avoided.

  Further, in the fuel cell system of the present embodiment, the stack body 3 is accommodated in a space defined inside the frame 5 by the frame 5 and the end plates 10 a and 10 b, and the frame 5 is opposite to the spring box 11. Since it functions as a structural member that bears the force, the fuel cell stack 1 is smaller than the conventional one.

  Further, since the end plates 10a and 10b that support the stack body 3 and the fluid pipings 16a to 16f connected to the stack body 3 are all made of resin, the stack body 3 is electrically isolated from the surrounding members and insulated. Can do.

  Furthermore, since the high voltage case 20 that accommodates the high voltage relay 25 is disposed on the rear side in the stack accommodating space R, even when the user of the vehicle body 41 opens the hood (not shown), The possibility that the user touches the high voltage case 20 is low and it is safe.

  In addition, between the frame 5 and the end plates 10a and 10b, between the through holes formed in the end plate 10a and the fluid pipes 16a to 16f, the long holes 5d and the hydrogen permeable membrane 18 formed in the frame 5 Between the through-hole formed in the frame 5 and the wiring of the hydrogen concentration sensor, between the upper wall portion 5c of the frame 5 and the cell monitor case 30, and between the through-hole formed in the cell monitor case 30 and the cell monitor Seals are made at all points between the wiring, between the upper wall portion 5c of the frame 5 and the high voltage case 20, and between the through holes 36 formed in the high voltage case 20 and the output cables Ca 'and Cb'. Since the members are disposed, the inside of the fuel cell stack 1 can be waterproofed.

  The above-described embodiment is an example of a preferred embodiment of the present invention, but is not limited thereto, and various modifications can be made without departing from the scope of the present invention. For example, in the present embodiment, the high voltage case 20 that accommodates the high voltage relay 25 is provided on the upper surface on the outer side of the frame 5. It may be provided on the outer surface. Even if the high voltage relay 25 is arranged in this portion, it is possible to prevent the high voltage relay 25 from interfering with other components in the same manner as described above, so that damage can be suppressed. Further, even if the high voltage relay 25 is arranged on the ceiling surface or the bottom surface inside the frame 5, similarly to the above, the high voltage relay 25 can be prevented from interfering with other surrounding parts, so that damage is suppressed. be able to. However, when the water level increases and the vehicle body 41 is submerged, if the high voltage relay 25 is under the fuel cell stack 1, there is a possibility of being submerged and short-circuiting. Therefore, the high voltage relay 25 is connected to the fuel cell stack 1. The upper side is preferable.

  In the present embodiment, the fuel cell system is mounted on the vehicle body 41 such as an automobile. However, this is only a preferred example, and the fuel cell system of the present invention is not limited to the vehicle body 41 and is mounted on any other moving body. be able to.

It is a perspective view which shows embodiment of the fuel cell stack of this invention. It is a sectional side view of a fuel cell stack. It is a disassembled perspective view of the principal part of a fuel cell stack. It is the schematic which shows the state which mounted the fuel cell stack in the vehicle body.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Fuel cell stack, 2 ... Cell, 3 ... Stack main body, 5 ... Frame, 10a, 10b ... End plate, 25 ... High voltage relay (relay)

Claims (5)

A stack body in which a plurality of cells are stacked;
A frame surrounding the stack body;
An end plate fixed to both ends of the frame, and defining a space inside the frame;
A relay connected to a power output terminal provided in the stack body;
A fuel cell stack comprising:
The fuel cell stack, wherein the relay is provided above or below the stack body when the stacking direction of the cells is a horizontal direction .   2. The fuel cell stack according to claim 1, wherein the relay is disposed on an upper surface or a lower surface on the outer side of the frame, or on a ceiling surface or a bottom surface on the inner side of the frame.   The fuel cell stack according to claim 1, further comprising a reaction gas supply device that supplies a reaction gas to at least one end of the stack body in the cell stacking direction. The fuel cell stack according to claim 1 or 2,
A fuel cell system comprising: a reaction gas supply device that supplies a reaction gas to the stack body. A fuel cell system according to claim 4,
A motor that receives supply of electric power from the stack body and generates a moving propulsion force of the moving body;
And a power control device that is connected to the stack body via the relay and controls the supply of power generated by the stack body to the motor.

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