JP6379859B2 - Fuel cell and fuel cell system - Google Patents

Description

  The present invention relates to a fuel cell and a fuel cell system including the fuel cell.

  BACKGROUND ART A fuel cell (a solid oxide fuel cell: SOFC (Solid Oxide Fuel Cell) or the like) generates electricity by causing an electrochemical reaction between a hydrogen-containing gas containing hydrogen and air. As a fuel cell such as a flat plate type SOFC (flat plate solid oxide fuel cell), a fuel cell stack configured by alternately stacking a plurality of power generation cells and separators (interconnectors), and a heat insulation housing the fuel cell stack There exists a thing provided with a member (refer to patent documents 1). By providing the heat insulating member, it is easy to keep the temperature inside the fuel cell stack and the temperature outside the fuel cell stack and inside the heat insulating container uniform.

  The fuel cell stack has plate-like members (upper base and lower base) that sandwich the power generation cell and the separator in the stacking direction of the power generation cell and the separator (hereinafter referred to as “stacking direction”). The upper base and the lower base are urged along the stacking direction so as to approach each other. Thereby, the clearance gap between a power generation cell and a separator becomes small, the leak of gas or a liquid is reduced, and the electrical conduction in a fuel cell is ensured or improved.

JP 2014-35990 A

  As a member for urging the upper base and the lower base in the stacking direction (hereinafter referred to as “biasing member”), for example, there is a compression coil spring made of ceramics (hereinafter referred to as “ceramic spring”). The ceramic spring is provided on the inner wall portion inside the heat insulating member. The ceramic spring biases at least one of the upper base and the lower base in a direction in which the upper base and the lower base are brought close to each other.

  However, ceramic springs have the property of being vulnerable to impacts. Therefore, if a certain level of impact is applied to the ceramic spring during operation of the fuel cell system, the ceramic spring may be damaged by the impact. In addition, ceramic springs are relatively expensive and thus increase the cost.

  Accordingly, an object of the present invention is to provide a fuel cell including an urging member with reduced manufacturing cost of the fuel cell and improved impact resistance, and a fuel cell system including the fuel cell.

The present invention relates to a fuel cell stack configured by alternately stacking a plurality of power generation cells and separators, and an upper base that directly or indirectly sandwiches the fuel cell stack in the stacking direction of the power generation cells and the separator. and a lower base, is composed the lower base or the upper base integrally orthogonal, the fuel cell stack and the lower base and the upper platform relative to the stacking direction is covered respectively from the upper and lower directions in the stacking direction A heat insulating wall member that covers from the lateral direction, the heat insulating wall member that insulates the space inside and outside the heat insulating wall member, and the lower base or the base And a biasing portion having a metal biasing member disposed in a space outside the heat insulating wall member for biasing at least one of the upper base.

  The biasing portion includes a moving member in which a portion near one end is fixed to the upper base and a portion near the other end relative to the portion near the one end is movable with respect to the lower base. Preferably, the member drives the moving member in a direction in which the upper base is brought closer to the lower base.

  Further, the moving member is configured by a guide member extending toward the lower base along the stacking direction, the lower base includes a guide hole through which the guide member is inserted, and the guide member is the guide Preferably, the upper base is inserted into the hole, and the upper base is configured to be movable with respect to the lower base in a state where the guide member is inserted into the guide hole.

  Furthermore, in the fuel cell system including the fuel cell according to the present invention, air heated in the vicinity of the portion of the guide member protruding from the guide hole to a space outside the heat insulating wall member is used as the heat insulating wall member. It is related with the fuel cell system which has the to-be-heated air distribution line distribute | circulated to the space inside.

  ADVANTAGE OF THE INVENTION According to this invention, the manufacturing cost of a fuel cell can be reduced, and a fuel cell provided with the biasing member by which impact resistance was improved, and a fuel cell system provided with this fuel cell can be provided.

It is the schematic which shows the fuel cell system 1 provided with the fuel cell 2 which concerns on embodiment of this invention. It is a schematic sectional drawing of the fuel cell 2 which concerns on embodiment of this invention.

[Embodiment]
Hereinafter, a fuel cell 2 and a fuel cell system 1 including the fuel cell 2 according to an embodiment of the present invention will be described with reference to FIGS. 1 and 2. FIG. 1 is a schematic diagram showing a fuel cell system 1 including a fuel cell 2 according to an embodiment of the present invention. FIG. 2 is a schematic cross-sectional view of the fuel cell 2 according to the embodiment of the present invention.

  The fuel cell system 1 includes a fuel cell 2, a combustor 3, a reformer 4, an evaporator 5, a heat insulating wall member 6, and an intake fan 51 (see FIG. 2). The fuel cell 2, the combustor 3, the reformer 4, the evaporator 5, the heat insulating wall member 6, and the intake fan 51 are accommodated in one case (not shown).

  The fuel cell system 1 includes a fuel gas supply line L1, a water supply line L2, an evaporative water supply line L3, a reformed gas supply line L4, an air supply line L5, a pre-combustion off-gas discharge line L6, And a post-combustion off-gas discharge line L7. The “line” is a general term for a flow path, a path, a pipe line, and the like.

[Description of line]
In the fuel gas supply line L1, one end of the fuel gas supply line L1 is connected to a fuel gas supply unit (not shown) capable of supplying a fuel gas G1 such as city gas, and the other end of the fuel gas supply line L1. The part is connected to the reformer 4. The fuel gas G1 is supplied from the fuel gas supply unit to the reformer 4 through the fuel gas supply line L1.

  One end of the water supply line L2 is connected to a water reservoir (not shown), and the other end of the water supply line L2 is connected to the evaporator 5. A pump 7 is connected in the middle of the water supply line L2. The pump 7 pressurizes the reforming water W1 from the water storage unit in order to supply the reforming water W1 to the evaporator 5. The reforming water W <b> 1 in the water storage unit is supplied to the evaporator 5 through the water supply line L <b> 2 from the water storage unit by driving the pump 7.

  In the evaporated water supply line L3, one end of the evaporated water supply line L3 is connected to the evaporator 5, and the other end of the evaporated water supply line L3 is connected to the reformer 4. Reformed water W1 evaporated by the evaporator 5 (hereinafter referred to as “evaporated water W2”) is supplied from the evaporator 5 to the reformer 4 through the evaporated water supply line L3.

  In the reformed gas supply line L4, one end of the reformed gas supply line L4 is connected to the reformer 4, and the other end of the reformed gas supply line L4 is connected to the fuel cell 2. The reformed gas G2 containing hydrogen generated in the reformer 4 flows through the reformed gas supply line L4, is supplied to the fuel cell 2, and is used for power generation.

  In the air supply line L5, one end of the air supply line L5 is connected to a blower (not shown) and a filter (not shown) as an air supply part for supplying the oxygen-containing air A1 to the fuel cell 2. Has been. The other end of the air supply line L5 is connected to the fuel cell 2. That is, the air A1 passes through the filter from the blower, flows through the air supply line L5, and is supplied to the fuel cell 2.

  In the pre-combustion off-gas discharge line L6 (hereinafter referred to as “off-gas discharge line L6”), one end of the off-gas discharge line L6 is connected to the fuel cell 2, and the other end of the off-gas discharge line L6 is connected to the combustor 3. It is connected. The pre-combustion off-gas G3 discharged from the fuel cell 2 flows through the off-gas discharge line L6 and is supplied to the combustor 3.

  In the post-combustion off-gas exhaust line L7 (hereinafter referred to as “off-gas exhaust line L7”), one end of the off-gas exhaust line L7 is connected to the combustor 3, and the other end of the off-gas exhaust line L7 is outdoors (not shown). Open). The pre-combustion off-gas G3 (post-combustion off-gas G4) combusted by the combustor 3 flows through the off-gas discharge line L7 and is discharged outdoors.

[Description of each device]
As the fuel cell 2, a solid oxide fuel cell (SOFC) is used. The fuel cell 2 has a fuel cell stack 21 (see FIG. 2 described later). The fuel cell stack 21 is configured by alternately stacking a plurality of power generation cells (not shown) and separators (not shown).

  The power generation cell includes an anode, a cathode, and an electrolyte layer provided between the anode and the cathode. The anode is made of nickel or the like.

  The fuel cell 2 reacts the reformed gas G2 supplied to the anode from the reformer 4 via the reformed gas supply line L4 and the oxygen in the air A1 supplied to the cathode from the air supply line L5. Thus, power generation can be performed. The operating temperature, which is the temperature at the time of power generation by the fuel cell 2, is about 500 ° C to 1000 ° C. The electricity generated by the fuel cell 2 is sent to a power conditioner (not shown) and converted into an AC voltage.

  The fuel cell 2 discharges anode off-gas that is off-gas from the anode and cathode off-gas that is off-gas from the cathode. The anode off gas (pre-combustion off gas G3) contains anode gas (hydrogen). Therefore, a combustion process is performed by the combustor 3 in order to inactivate the anode gas (hydrogen).

  The combusted anode off-gas (that is, off-combustion off-gas G4) and cathode off-gas are discharged out of the fuel cell system 1 through an off-gas discharge line L7 connected to the downstream side of the combustor 3.

  The combustor 3 includes a burner, a furnace, or the like. The pre-combustion off-gas G3 supplied through the off-gas discharge line L6 is combusted, that is, the anode off-gas and the cathode off-gas are combusted, and a high-temperature post-combustion off-gas G4 is generated.

  The reformer 4 generates the reformed gas G2 containing hydrogen on the catalyst based on the fuel gas G1 supplied from the fuel gas supply line L1 and the evaporated water W2 supplied from the evaporated water supply line L3. The reformed gas G2 containing hydrogen generated by the reformer 4 is supplied to the fuel cell 2 via the reformed gas supply line L4. The operating temperature of the reformer 4 is about 500 ° C to 800 ° C.

  The evaporator 5 evaporates the reformed water W1 supplied from the water supply line L2. The reformed water W1 (evaporated water W2) evaporated by the evaporator 5 is supplied to the reformer 4 through the evaporated water supply line L3.

  The heat insulating wall member 6 is disposed so as to accommodate the fuel cell 2, the combustor 3, the reformer 4, and the evaporator 5. The heat insulating wall member 6 performs heat insulation between the space 41 (see FIG. 2) inside the heat insulating wall member 6 and the space 42 (see FIG. 2) outside.

  Next, the details of the fuel cell 2 and the fuel cell system 1 including the fuel cell 2 will be described with reference to FIG. In FIG. 2, illustration of various lines L <b> 1 to L <b> 7 arranged inside the heat insulating wall member 6 is omitted for simplification of description. In the following description, the stacking direction of the power generation cell and the separator is described as “stacking direction D1”, and the lateral direction orthogonal to the stacking direction D1 is described as “transverse direction D2”.

  The fuel cell 2 includes a heat insulating wall member 6, a fuel cell stack 21, an upper base 22, a lower base 23, and a pair of urging portions 30. The heat insulating wall member 6 is fixed to a case (not shown) constituting the outer shell of the fuel cell system 1. An intake fan 51 and a heated air circulation line L8 are arranged between the heat insulating wall member 6 and the case.

The fuel cell stack 21 is configured by alternately stacking a plurality of power generation cells and separators.
The upper base 22 and the lower base 23 are constituted by plate-like members having substantially the same shape. The lower surface of the upper substrate 22 is in contact with the upper surface of the fuel cell stack 21. The upper surface of the lower base 23 is in contact with the lower surface of the fuel cell stack 21. The upper base 22 and the lower base 23 directly press the fuel cell stack 21 in the stacking direction D1.

  When the fuel cell stack 21 is pressed between the upper base 22 and the lower base 23 in the stacking direction D1, the gap between the power generation cell and the separator is reduced, and leakage of gas and liquid is reduced. Is ensured or improved.

  The area of the lower surface of the upper substrate 22 is large enough to cover the entire upper surface of the fuel cell stack 21. The area of the upper surface of the lower base 23 is large enough to cover the entire lower surface of the fuel cell stack 21. A plurality of guide holes 23 a are provided in the peripheral portion of the lower base 23 (region not facing the fuel cell stack 21). The guide hole 23a penetrates the lower base 23 in the stacking direction D1. Further, a heat recovery hole 23b is provided on the center side of the lower base 23 (region facing the fuel cell stack 21). The heat recovery hole 23b penetrates the lower base 23 in the stacking direction D1.

The heat insulating wall member 6 covers the fuel cell stack 21 from the vertical direction in the stacking direction D1 and also from the lateral direction D2. The heat insulating wall member 6 is configured integrally with the lower base 23. Here, “integrally configured” means not only a mode in which the two are integrally formed, but also the result that the heat insulating wall member 6 and the lower base 23 are relatively immovably integrated as a result of connecting separate bodies. Also included are the embodiments made.
The heat insulating wall member 6 may be configured integrally with the upper base 21.

  The heat insulating wall member 6 is provided with a plurality of guide holes 6 a having substantially the same diameter as the guide holes 23 a in the lower base 23. The guide hole 6a penetrates the heat insulating wall member 6 in the stacking direction D1. The guide hole 23a and the guide hole 6a are disposed substantially coaxially in the stacking direction D1. In addition, a communication hole 6 b is provided on the side wall of the heat insulating wall member 6 to allow the space 41 inside the heat insulating wall member 6 to communicate with the space 42 outside. Further, a heat recovery passage 6d having a U-shaped cross section is provided on the lower end side of the heat insulating wall member 6. The heat recovery passage 6d passes through the inside of the heat insulating wall member 6 from the upper end side of the heat insulating wall member 6 and is connected to the heat recovery hole 23b.

  The urging unit 30 includes a guide member 32 and an urging member 34. The guide member 32 is composed of a rod-shaped rod member having male screws at both ends. In the following description, the guide member 32 is constituted by a rod member 32. Further, the fuel cell 2 has a plurality of urging units 30. However, since these urging units 30 have substantially the same configuration, only one urging unit 30 is described in the following description. explain.

The urging member 34 is a compression coil spring made of a metal (for example, stainless steel) having high impact resistance and corrosion resistance.
The rod member 32 is configured to extend from the upper base 22 toward the lower base 23 along the stacking direction D1. One end 32 a of the rod member 32 is fixed to the lower end 22 a of the peripheral edge of the upper base 22. Specifically, the one end portion 32a is fixed to the lower end portion 22a by being screwed into a female screw portion (not shown) provided in the lower end portion 22a. The other end 32 b of the rod member 32 passes through the guide hole 23 a and the guide hole 6 a and protrudes into the space 42 outside the heat insulating wall member 6. The rod member 32 is movable relative to the lower base 23 together with the upper base 22 while the other end 32b is guided in the stacking direction D1 by the guide hole 23a and the guide hole 6a.

  An urging member 34 is fitted to the other end portion 32b side of the rod member 32 protruding into the space 42 outside the heat insulating wall member 6 (the other end portion 32b of the rod member 32 penetrating the heat insulating wall member 6). . A nut 33 is screwed into the other end portion 32 b of the rod member 32. The urging member 34 is compressed in the stacking direction D <b> 1 between the outer wall portion 6 c on the lower end side of the heat insulating wall member 6 and the nut 33.

  The other end portion 32b of the rod member 32 is moved downward by the urging force of the urging member 34 that has been compressed. With the movement of the other end 32b, the upper base 22 to which the one end 32a is fixed is moved in a direction approaching the lower base 23. As a result, the distance between the upper base 22 and the lower base 23 is relatively reduced, and the fuel cell stack 21 disposed between the upper base 22 and the lower base 23 is pressed in the stacking direction D1.

The fuel cell system 1 including the fuel cell 2 of the present embodiment has a heated air circulation line L8. An intake fan 51 is connected to one end of the heated air circulation line L8. A communication hole 6b, a heat recovery passage 6d, and a heat recovery hole 23b are inserted into the other end portion of the heated air circulation line L8 and face the lower end side of the fuel cell stack 21.
The intake fan 51 (one end portion of the heated air circulation line L8) is disposed outside the heat insulating wall member 6 and in the vicinity of the rod member 32 (the other end portion 32b) penetrating the guide hole 23a and the guide hole 6a. . The heat of the inner space 41 (air A2 heated in the inner space 41) transmitted from the inner space 41 of the heat insulating wall member 6 to the outer space 42 via the rod member 32 is the rod member 32 (the other end portion). The gas in the vicinity of 32b) is heated. The heated gas is sucked by the intake fan 51, flows through the heated air recovery line L9, and is recovered at the lower end side of the fuel cell stack 21 (that is, the heated air is supplied to the cathode of the fuel cell stack 21). )
Here, “the vicinity of the rod member 32 (the other end portion 32 b)” means that the rod fan 32 can recover the gas heated by the heat transmitted to the other end portion 32 b of the rod member 32 by the intake fan 51. It means that it is near (the other end 32b).

According to the fuel cell 2 of the present embodiment, the following effects are exhibited.
The fuel cell 2 of the present embodiment includes a fuel cell stack 21 configured by alternately stacking a plurality of power generation cells and separators, and the fuel cell stack 21 directly or indirectly in the stacking direction D1 between the power generation cells and the separator. The upper base 22 and the lower base 23 sandwiched between the two and the lower base 23 are integrally formed to cover the fuel cell stack 21 from the vertical direction in the stacking direction D1 and from the lateral direction D2 orthogonal to the stacking direction. A heat insulating wall member 6 that insulates the space 41 inside the heat insulating wall member 6 and the outer space 42, and the lower base 23 or the upper base 22 in a direction in which the lower base 23 and the upper base 22 are brought closer to each other. And an urging portion 30 having an urging member 34 disposed in a space 42 outside the heat insulating wall member 6 that urges at least one of the bases 22.

  Further, the biasing portion 30 has a portion near one end (one end portion 32a) fixed to the upper base 22 and a portion near the other end (the other end portion 32b) with respect to the portion near the one end (one end portion 32a). The urging member 34 drives the moving member 32 in a direction in which the upper base 22 approaches the lower base 23.

  Further, the moving member 32 is configured by a guide member 32 extending toward the lower base 23 along the stacking direction D1, and the lower base 23 has a guide hole 23a through which the guide member 32 is inserted. The upper base 22 is inserted into the guide hole 23a, and is configured to be movable with respect to the lower base 23 in a state where the guide member 32 is inserted into the guide hole 23a.

  According to the configuration as described above, the biasing member 34 (metallic coil spring) disposed in the space 42 outside the heat insulating wall member 6 is laminated with the distance between the upper base 22 and the lower base 23 relatively close. The fuel cell stack 21 can be pressed in the direction D1.

  That is, according to the fuel cell 2 of the present embodiment, the urging member 34 can be disposed in the outer space 42 instead of the inner space 41 of the heat insulating wall member 6. Accordingly, it is not necessary to configure the biasing member 34 with an expensive member (for example, ceramics) that can withstand high temperatures, and a metal (for example, stainless steel) that has high impact resistance and can achieve a reduction in the manufacturing cost of the fuel cell. ). That is, in the present embodiment, it is possible to provide the fuel cell 2 including the urging member 34 in which the manufacturing cost of the fuel cell 2 is reduced and the impact resistance is improved.

  Furthermore, according to the fuel cell system 1 including the fuel cell 2 of the present embodiment, the heated air A2 in the vicinity of the portion of the guide member 32 protruding from the guide hole 23a to the space 42 outside the heat insulating wall member 6 is supplied. And a heated air circulation line L8 that circulates into the space 41 inside the heat insulating wall member 6.

  According to such a configuration, the gas heated by the heat of the inner space 41 transmitted from the inner space 41 of the heat insulating wall member 6 to the outer space 42 via the rod member 32 is absorbed by the intake fan 51. Then, it can be recovered to the lower end side of the fuel cell stack 21 via the heated air circulation line L8. That is, the gas heated by the heat flowing out to the space 42 outside the heat insulating wall member 6 can be reused in the fuel cell stack 21.

  Furthermore, since the gas heated by the heat transmitted to the other end 32b of the rod member 32 is recovered by the intake fan 51 (heated air circulation line L8), the temperature of the other end 32b of the rod member 32 is lowered. can do. Thereby, for example, during operation of the fuel cell system 1, accidents (burns, etc.) that occur due to contact with the other end 32b can be reduced. That is, in the fuel cell system 1 including the fuel cell 2 of the present embodiment, safety is improved.

The present invention is not limited to the above-described embodiments, and can be modified within the technical scope described in the claims.
For example, in the above description, no member is disposed between the upper base 22 and the fuel cell stack 21 and between the lower base 23 and the fuel cell stack 21, but the present invention is not limited to this. For example, a predetermined member is disposed between the upper substrate 22 and the fuel cell stack 21 and / or between the lower substrate 23 and the fuel cell stack 21, and the fuel cell stack 21 is connected to the upper substrate via the predetermined member. 22 and / or the lower base 23 may be sandwiched indirectly.

  Moreover, in the above-mentioned description, although the one end part 32a of the rod member 32 is being fixed to the lower end part 22a of the upper base | substrate 22, this invention is not limited to this. For example, the upper base 22 may be penetrated by the one end portion 32 a of the rod member 32, and a portion near the one end portion 32 a (a portion near one end) may be fixed to the upper base 22.

  In the above description, the nut 33 is fixed (screwed) to the other end 32b of the rod member 32, but the present invention is not limited to this. For example, the nut 33 may be fixed to a portion near the other end portion 32b (a portion closer to the other end).

  In the above description, the urging member 34 is provided only on the lower base 23 side, but the present invention is not limited to this. For example, the urging member 34 is disposed in the space 42 outside the heat insulating wall member 6 so as to urge at least one of the lower base 23 or the upper base 22 in a direction in which the lower base 23 and the upper base 22 are brought close to each other. It only has to be.

  Further, the configuration is not limited to the configuration in which the other end portion of the heated air circulation line L8 is opposed to the lower end side of the fuel cell stack 21. For example, the other end portion of the heated air circulation line L <b> 8 can be opposed to the upper end side of the fuel cell stack 21 through the upper substrate 22 from the upper end side of the upper substrate 22. With this configuration, the heat of the inner space 41 transmitted through the rod member 32 is absorbed by the intake fan 51 and recovered to the upper end side of the fuel cell stack 21 through the heated air circulation line L8. Can do.

DESCRIPTION OF SYMBOLS 1 Fuel cell system 2 Fuel cell 6 Heat insulation wall member 21 Fuel cell stack 22 Upper base 23 Lower base 23a Guide hole 30 Energizing part 32 Moving member (guide member, rod member)
34 Energizing member 41 Inner space 42 Outer space L8 Heated air circulation line A2 Heated air D1 Stacking direction D2 Horizontal direction

Claims (4)

A fuel cell stack configured by alternately stacking a plurality of power generation cells and separators;
An upper base and a lower base sandwiching the fuel cell stack directly or indirectly in the stacking direction of the power generation cell and the separator;
The lower base or configured the upper base and integrally, the fuel cell stack and the lower base and the upper platform, covering the lateral direction perpendicular to the stacking direction is covered respectively from the upper and lower directions in the stacking direction A heat insulating wall member that insulates the space inside and outside the heat insulating wall member;
A biasing force having a metal biasing member disposed in a space outside the heat insulating wall member for biasing at least one of the lower base and the upper base in a direction in which the lower base and the upper base are brought closer to each other. A fuel cell. The biasing portion includes a moving member in which a portion near one end is fixed to the upper base and a portion near the other end relative to the portion near the one end is movable with respect to the lower base,
The fuel cell according to claim 1, wherein the urging member drives the moving member in a direction in which the upper base is brought closer to the lower base. The moving member is constituted by a guide member extending toward the lower base along the stacking direction,
The lower base has a guide hole through which the guide member is inserted, and the guide member is inserted into the guide hole.
The fuel cell according to claim 2, wherein the upper base is configured to be movable with respect to the lower base in a state where the guide member is inserted into the guide hole. A fuel cell according to claim 3,
A fuel cell having a heated air circulation line that circulates air heated in the vicinity of the portion of the guide member protruding from the guide hole to the space outside the heat insulating wall member to the space inside the heat insulating wall member. system.

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