CN111697250A

CN111697250A - Fuel cell system and temperature adjustment method for fuel cell stack

Info

Publication number: CN111697250A
Application number: CN202010170624.3A
Authority: CN
Inventors: 吉富亮一
Original assignee: Honda Motor Co Ltd
Current assignee: Honda Motor Co Ltd
Priority date: 2019-03-15
Filing date: 2020-03-12
Publication date: 2020-09-22
Also published as: JP2020149933A; JP7098560B2

Abstract

The present disclosure relates to a fuel cell system and a temperature adjustment method of a fuel cell stack. A fuel cell system (10) is provided with: the fuel cell stack (12) and a refrigerant pipe (52) that is connected to an end plate (30a) of the fuel cell stack (12) and through which a refrigerant flows. The refrigerant pipe (52) includes: a refrigerant supply pipe (52a) for supplying a refrigerant to the fuel cell stack (12), and a refrigerant discharge pipe (52b) for discharging the refrigerant from the fuel cell stack (12). A structure (60) is provided in the vicinity of the end plate (30a) of each of the refrigerant supply pipe (52a) and the refrigerant discharge pipe (52 b). In the method for adjusting the temperature of the fuel cell stack (12), the structure (60) is set to a state in which the flow of the coolant is suppressed or a state in which the flow of the coolant is blocked, thereby maintaining the heat-retaining state of the fuel cell stack (12).

Description

Fuel cell system and temperature adjustment method for fuel cell stack

Technical Field

The present invention relates to a fuel cell system including a cooling pipe for circulating a coolant through a fuel cell stack, and a method for adjusting the temperature of the fuel cell stack.

Background

The fuel cell system generates power in the fuel cell stack by circulating (supplying and discharging) the anode gas and the cathode gas through a reactant gas pipe connected to the fuel cell stack. As shown in patent document 1, the fuel cell system adjusts the temperature of the fuel cell stack during power generation by circulating a refrigerant through a refrigerant pipe connected to the fuel cell stack.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open No. 2006-147315

Disclosure of Invention

Problems to be solved by the invention

However, when the temperature sharply decreases after the fuel cell stack stops generating electricity, the energy required for starting increases when the operation is resumed as soon as possible thereafter. In addition, when there is a high chance that the temperature of the fuel cell stack will drop sharply, the deterioration will be accelerated and the life will be shortened. Therefore, the fuel cell system disclosed in patent document 1 includes a heat accumulator that heats a coolant, and thereby keeps warm of the fuel cell stack when power generation is stopped.

However, in a configuration in which a heat accumulator is provided as in the fuel cell system disclosed in patent document 1, the system becomes complicated, and problems such as an increase in manufacturing cost and an increase in size of the system occur.

The present invention has been made in connection with the above-described technology, and an object thereof is to provide a fuel cell system and a method for adjusting the temperature of a fuel cell stack, which can reduce a decrease in the temperature of the fuel cell stack due to the flow of a refrigerant after the stop of power generation while suppressing the complexity of the system.

Means for solving the problems

In order to achieve the above object, a first aspect of the present invention relates to a fuel cell system including: in the fuel cell system, the refrigerant pipe includes a refrigerant supply pipe for supplying the refrigerant to the fuel cell stack and a refrigerant discharge pipe for discharging the refrigerant from the fuel cell stack, and a structure for suppressing or preventing the flow of the refrigerant is provided in a position near the end plate of each of the refrigerant supply pipe and the refrigerant discharge pipe.

In order to achieve the above object, a second aspect of the present invention relates to a method for adjusting the temperature of a fuel cell stack in which a refrigerant pipe for flowing a refrigerant is connected to an end plate of the fuel cell stack, wherein the refrigerant pipe includes a refrigerant supply pipe for supplying the refrigerant to the fuel cell stack, a refrigerant discharge pipe for discharging the refrigerant from the fuel cell stack, and a pump for circulating the refrigerant, a structure is provided in a vicinity of the end plate of each of the refrigerant supply pipe and the refrigerant discharge pipe, the pump is driven and a state in which the refrigerant passes through the structure is set at a time of power generation of the fuel cell stack to cool the fuel cell stack, and the driving of the pump is stopped and the structure is set to a state in which the refrigerant is inhibited from flowing or is prevented from flowing at a time of power generation stop of the fuel cell stack Thereby maintaining the warm state of the fuel cell stack.

ADVANTAGEOUS EFFECTS OF INVENTION

The fuel cell system described above includes the structural body at a position near the end plate of the refrigerant pipe, and thus can suppress or prevent the flow of the refrigerant through the refrigerant pipe when the operation of the fuel cell stack is stopped. That is, in the fuel cell system, the structure suppresses the discharge of the refrigerant having a raised temperature from the fuel cell stack or the supply of the refrigerant having a low temperature to the fuel cell stack, and thus the temperature drop of the fuel cell stack can be reduced. The chance of a sharp drop in the temperature of the fuel cell stack is reduced, whereby the life thereof can be extended. Further, the structure can be easily installed in the refrigerant pipe without complicating the system, and therefore, the system can be downsized and the manufacturing cost can be reduced.

The above objects, features and advantages will be readily understood from the following description of the embodiments with reference to the accompanying drawings.

Drawings

Fig. 1 is an explanatory diagram schematically showing the overall configuration of a fuel cell system according to an embodiment of the present invention.

Fig. 2 is an explanatory diagram schematically showing the structures of the fuel cell stack and the cooling device.

Fig. 3A is a cross-sectional view showing a state of suppressing the flow of the refrigerant by the valve body provided in the refrigerant pipe. Fig. 3B is a cross-sectional view taken along line IIIB-IIIB of fig. 3A. Fig. 3C is a cross-sectional view showing a state of flow of the refrigerant by the valve body provided in the refrigerant pipe. FIG. 3D is a cross-sectional view taken along line IIID-IIID of FIG. 3C.

Fig. 4A is a cross-sectional view showing a state of blocking the flow of the refrigerant by the reed valve according to the first modification. Fig. 4B is a cross-sectional view taken along line IVB-IVB of fig. 4A. Fig. 4C is a sectional view showing a flow state of the refrigerant generated by the reed valve of fig. 4A. Fig. 4D is a sectional view taken along line IVD-IVD of fig. 4C.

Fig. 5A is a cross-sectional view showing a blocked state of the refrigerant by the shutoff valve according to the second modification. Fig. 5B is a cross-sectional view showing a flow state of the refrigerant generated by the shutoff valve of fig. 5A.

Fig. 6 is an explanatory diagram schematically showing the overall configuration of a fuel cell system according to a third modification.

Fig. 7 is an explanatory view schematically showing a fuel cell stack and a peripheral portion thereof in a fuel cell system according to a fourth modification.

Detailed Description

Hereinafter, the present invention will be described in detail by referring to the drawings by referring to preferred embodiments.

As shown in fig. 1, a fuel cell system 10 according to an embodiment of the present invention includes a fuel cell stack 12, an anode gas system device 14, a cathode gas system device 16, a cooling device 18, and a control device 20. The fuel cell system 10 is mounted in, for example, a motor room (not shown) of a fuel cell automobile (vehicle 11).

The fuel cell stack 12 generates power based on an anode gas (fuel gas such as hydrogen) supplied from an anode gas system device 14 and a cathode gas (oxidant gas such as air) supplied from a cathode gas system device 16. When the fuel cell stack 12 generates electric power, the cooling device 18 supplies a coolant (cooling water or the like) to the fuel cell stack 12 and discharges the coolant from the fuel cell stack 12 to cool the fuel cell stack 12 (temperature adjustment).

As shown in fig. 2, the fuel cell stack 12 includes a plurality of power generation cells 22 that generate power by an electrochemical reaction between an anode gas and a cathode gas. In a state where the fuel cell stack 12 is mounted on the vehicle 11, the plurality of power generation cells 22 are configured as a stacked body 24 in which electrode surfaces are stacked in the vehicle width direction with an upright posture.

Terminal plates

26a, 26b,

insulating plates

28a, 28b, and

end plates

30a, 30b are stacked in this order on both ends of the stacked body 24 in the stacking direction, respectively, and facing outward. Further, a plurality of power generation cells 22 may be stacked in the front-rear direction and the gravity direction of the vehicle 11.

The power generating unit cell 22 is constituted by a membrane electrode assembly 32 (hereinafter referred to as "MEA 32") and two separators 34 sandwiching the MEA 32. The outer peripheries of the separators 34 between the adjacent power generating cells 22 are joined to each other to constitute an integral joined separator.

The MEA 32 of the power generation cell 22 includes an electrolyte membrane 36 (e.g., a solid polymer electrolyte membrane (cation exchange membrane)), an anode electrode 38 provided on one surface of the electrolyte membrane 36, and a cathode electrode 40 provided on the other surface of the electrolyte membrane 36. An anode gas passage 38a through which an anode gas flows and a cathode gas passage 40a through which a cathode gas flows are formed on the surfaces of the two separators 34 that face the MEA 32. Further, a refrigerant flow path 42 through which a refrigerant flows is formed in a surface where the two separators 34 are opposed to each other.

The stack 24 includes a plurality of communication holes (anode gas communication hole 44, cathode gas communication hole 46, and refrigerant communication hole 48) through which the anode gas, the cathode gas, and the refrigerant flow in the stacking direction of the power generation cells 22, respectively. In the stack 24, the anode gas passage 44 communicates with the anode gas flow field 38a, the cathode gas passage 46 communicates with the cathode gas flow field 40a, and the coolant passage 48 communicates with the coolant flow field 42.

The anode gas supplied to the stack 24 flows through the anode gas passage 44 (anode gas supply passage 44a) and flows into the anode gas flow field 38 a. The anode off-gas generated by the anode electrode 38 for power generation flows from the anode gas flow field 38a into the anode gas passage 44 (anode gas discharge passage 44b) and is discharged from the stack 24.

The cathode gas supplied to the stack 24 flows through the cathode gas passage 46 (cathode gas supply passage 46a) and flows into the cathode gas flow field 40 a. The cathode exhaust gas generated by the cathode electrode 40 for power generation flows from the cathode gas flow field 40a into the cathode gas passage 46 (cathode gas discharge passage 46b) and is discharged from the stack 24.

The refrigerant supplied to the stacked body 24 flows through the refrigerant communication holes 48 (refrigerant supply communication holes 48a) and flows into the refrigerant flow field 42. The coolant that cools the power generation cells 22 flows from the coolant flow field 42 into the coolant passage 48 (coolant discharge passage 48b) and is discharged from the stacked body 24.

A reactant gas pipe 50 for circulating the anode gas and the cathode gas and a refrigerant pipe 52 for circulating the refrigerant are connected to the end plate 30a provided at one end of the stacked body 24. The reactant gas pipe 50 includes an anode gas supply pipe 50a communicating with the anode gas supply passage 44a, an anode gas discharge pipe 50b communicating with the anode gas discharge passage 44b, a cathode gas supply pipe 50c communicating with the cathode gas supply passage 46a, and a cathode gas discharge pipe 50d communicating with the cathode gas discharge passage 46 b. The refrigerant pipe 52 includes a refrigerant supply pipe 52a communicating with the refrigerant supply passage 48a and a refrigerant discharge pipe 52b communicating with the refrigerant discharge passage 48 b.

The fuel cell stack 12 includes a stack case 54 in which the entire stack 24 including the

end plates

30a and 30b is accommodated in the space portion 54 a. The stack case 54 may be configured as a cylindrical body surrounding the periphery of the power generation cell 22 perpendicular to the stacking direction of the stacked body 24, and the end portions of the cylindrical body may be closed by the

end plates

30a and 30 b.

The reactant gas pipe 50 (anode gas supply pipe 50a, anode gas discharge pipe 50b, cathode gas supply pipe 50c, and cathode gas discharge pipe 50d) and the refrigerant pipe 52 (refrigerant supply pipe 52a and refrigerant discharge pipe 52b) connected to the end plate 30a penetrate the wall portion 55 at one end of the stack case 54 and are exposed to the outside of the stack case 54. A seal or the like may be provided at a through portion of the pipe of the stack case 54.

As shown in fig. 1 and 2, the cooling device 18 of the fuel cell system 10 is formed of the above-described refrigerant pipe 52, radiator 56, and pump 58 to form a circulation circuit for circulating the refrigerant with the fuel cell stack 12. Specifically, the refrigerant supply pipe 52a extends between the stacked body 24 (end plate 30a) and the radiator 56, and includes a pump 58 at a midway position thereof. The refrigerant discharge pipe 52b extends between the stacked body 24 (end plate 30a) and the radiator 56.

A radiator 56 of the cooling device 18 is provided in the vehicle 11 on the front side of the fuel cell stack 12 and on the lower side in the direction of gravity. Therefore, when the refrigerant pipes 52 (the refrigerant supply pipe 52a and the refrigerant discharge pipe 52b) are exposed from the wall portion 55 of the stack case 54, the refrigerant pipes 52 are bent at positions close to the wall portion 55 and extend forward and downward. The material constituting the refrigerant pipe 52 is not particularly limited, and any of a metal material and a resin material can be applied.

The radiator 56 is constituted by, for example, an internal pipe (not shown) communicating with the refrigerant pipe 52 and through which the refrigerant flows, and a radiator fan 56a, and cools the refrigerant in the internal pipe by cooling air generated in accordance with rotation of the radiator fan 56 a. The structure and the installation position of the heat sink 56 are not particularly limited.

The pump 58 is controlled by the control device 20 to operate and circulate the refrigerant in the refrigerant supply pipe 52a, thereby supplying the refrigerant to the fuel cell stack 12. The refrigerant of the fuel cell stack 12 thus flows out to the refrigerant discharge pipe 52b, and flows to the radiator 56 based on the flow. The cooling device 18 may be provided with a pump 58 in the refrigerant discharge pipe 52b instead of the refrigerant supply pipe 52a, or may be provided with a pump 58 in each of the refrigerant supply pipe 52a and the refrigerant discharge pipe 52 b.

The cooling device 18 may be provided with various devices not shown in the drawings, in addition to the above-described devices. Examples of the cooling device 18 include an ion exchanger for removing ions contained in the refrigerant, a storage tank for storing the refrigerant, and a temperature sensor for detecting the temperature of the refrigerant. The refrigerant supply pipe 52a and the refrigerant discharge pipe 52b can also be designed to extend in the appropriate directions. A bypass pipe, not shown, for bypassing the radiator 56 may be provided between the refrigerant supply pipe 52a and the refrigerant discharge pipe 52 b.

The fuel cell system 10 further includes a structural body 60 that suppresses the flow of the refrigerant in the refrigerant pipe 52 (suppresses the flow of the refrigerant) when the power generation of the fuel cell stack 12 is stopped. The structure 60 is provided in each of the refrigerant supply pipe 52a and the refrigerant discharge pipe 52 b.

Further, a structural body 60 is provided in the vicinity of the end plate 30a of the fuel cell stack 12. The "vicinity position" of the end plate 30a refers to a position closer to the end plate 30a than an intermediate position of the refrigerant pipe 52 extending between the end plate 30a and the components (the radiator 56, the pump 58, and the like) of the cooling device 18. For example, the vicinity position is a range of about 30cm or less from the connection point between the end plate 30a and the refrigerant pipe 52. The structural body 60 according to the present embodiment is provided at the limit of the stack case 54, and is thereby located sufficiently close to the end plate 30 a.

The structure 60 according to the present embodiment is configured as a valve body 62 that incompletely blocks (partially opens) the flow path of the refrigerant pipe 52 in a state where the flow of the refrigerant is stopped. The valve body 62 and the refrigerant pipe 52 in which the valve body 62 is disposed will be described below with reference to fig. 3A to 3D.

The refrigerant pipe 52 has a split structure of a plurality of pipes (a first pipe 64 and a second pipe 66), and the first pipe 64 and the second pipe 66 are connected by a relay pipe 68 to which the valve body 62 is fixed. That is, the valve body 62 and the relay pipe 68 constitute a pipe unit 69 for providing the valve body 62 at a middle position of the refrigerant pipe 52.

A pipe unit 69 is provided at a position overlapping the wall portion 55 at one end side of the stack case 54, and a package is provided between the wall portion 55 and the relay pipe 68, for example. The relay pipe 68 may be connected to the wall portion 55 of the stack case 54. The "boundary" of the stack case 54 includes a portion overlapping the wall portion 55 of the stack case 54, and also includes a portion adjacent to the wall portion 55 on the outer side or inner side of the wall portion 55 of the stack case 54. For example, when the first pipe 64 is present inside the stack case 54 and the second pipe 66 is present outside the stack case 54, the relay pipe 68 may be configured as a connector protruding from the stack case 54 to connect the second pipe 66.

The valve body 62 includes a fixing portion 70 fixed to the relay pipe 68 and an opening/closing portion 72 capable of opening and closing a flow path of the relay pipe 68 (refrigerant pipe 52). The fixing portion 70 and the opening/closing portion 72 are integrally formed.

The fixing portion 70 is formed in a ring shape and is fixed in close contact with the inner peripheral surface of the relay pipe 68 by an appropriate fixing method. The fixing method is not particularly limited, and a method such as welding, bonding, or fitting of another fixing member can be employed. Alternatively, the relay pipe 68 and the valve body 62 may be configured such that an engaged portion (a recess, a projection, or the like), not shown, is provided on one side and an engaging portion engaged with the engaged portion is provided on the other side.

The opening/closing portion 72 is constituted by a plurality of (three in the illustrated example) sheets 74. Each sheet 74 protrudes obliquely from one end of the fixing portion 70 toward the center of the relay pipe 68, thereby making the entire opening/closing portion 72 substantially conical. The direction in which the opening/closing portion 72 protrudes from the fixing portion 70 is the direction from the upstream to the downstream of the flow direction of the refrigerant. Therefore, the supply-side valve body 62a is disposed in the refrigerant supply pipe 52a so that the opening/closing portion 72 protrudes toward the end plate 30a, and the discharge-side valve body 62b is disposed in the refrigerant discharge pipe 52b so that the opening/closing portion 72 protrudes toward the radiator 56.

Each sheet 74 is formed in a triangular shape that divides the substantially conical shape of the opening/closing portion 72. Each thin sheet 74 is elastically deformed at the projecting end side at the base point of the fixing portion 70 based on the flow force of the refrigerant. Also, the protruding ends of the respective sheets 74 in this embodiment are separated from each other, forming a gap 76 between the protruding ends.

When the power generation of the fuel cell stack 12 is stopped, the flow of the coolant is stopped, and the above-described respective sheets 74 approach each other and the coolant hardly passes therethrough. However, the flow path is maintained in communication (the refrigerant is prevented from flowing) by slightly flowing the refrigerant through the gap 76. When the refrigerant flows in the opposite direction to the flow direction, the respective thin pieces 74 operate to close the gaps 76. During power generation of the fuel cell stack 12 (during circulation of the refrigerant), the sheets 74 are largely separated from each other, and an appropriate amount of the refrigerant flows.

The valve body 62 may be made of a rubber material (resin material) that can be elastically deformed appropriately by the circulation of the refrigerant by the pump 58. The rubber material is not particularly limited, but examples thereof include a thermosetting elastomer such as urethane rubber, silicone rubber, and fluororubber, a thermoplastic elastomer, and other elastomers.

The fuel cell system 10 according to the present embodiment is basically configured as described above, and the operation thereof will be described below.

As shown in fig. 1, the fuel cell system 10 supplies an anode gas from the anode gas system device 14 to the fuel cell stack 12 and supplies a cathode gas from the cathode system device to the fuel cell stack 12 under the control of the control device 20. As shown in fig. 2, in the fuel cell stack 12, the anode gas is supplied to the anode electrode 38 of each power generation cell 22, while the cathode gas is supplied to the cathode electrode 40 of each power generation cell 22, whereby each power generation cell 22 generates power. The fuel cell system 10 discharges anode off-gas during power generation from the fuel cell stack 12 to the anode gas system device 14, and discharges cathode off-gas during power generation from the fuel cell stack 12 to the cathode gas system device 16.

When the fuel cell stack 12 generates power, the fuel cell system 10 appropriately drives the pump 58 under the control of the controller 20 to circulate the coolant between the fuel cell stack 12 and the cooling device 18, thereby cooling the fuel cell stack 12. That is, the cooling device 18 supplies the coolant to the fuel cell stack 12 through the flow path of the coolant supply pipe 52 a. The supply-side valve element 62a provided in the refrigerant supply pipe 52a has a large opening of the opening/closing portion 72 (the plurality of thin pieces 74) and allows the refrigerant to flow smoothly in accordance with the flow force of the refrigerant toward the stacked body 24 (see fig. 3C and 3D).

In the fuel cell stack 12, the coolant supplied from the coolant supply pipe 52a passes through the coolant flow path 42 between the separators 34 that are adjacent to each other and engaged with each other, thereby cooling each power generation cell 22. The fuel cell system 10 discharges the heated coolant from the fuel cell stack 12 to the radiator 56 through the flow path of the coolant discharge pipe 52 b. At this time, the discharge-side valve element 62b provided in the refrigerant discharge pipe 52b opens the opening/closing portion 72 (the plurality of thin pieces 74) large in accordance with the flow force of the refrigerant toward the radiator 56, thereby allowing the refrigerant to flow smoothly. The radiator 56 is driven by a radiator fan 56a to cool the refrigerant.

The fuel cell system 10 stops the operations of the anode gas system device 14, the cathode gas system device 16, and the cooling device 18 when the power generation of the fuel cell stack 12 is stopped. The pump 58 of the cooling device 18 is stopped, and thus the refrigerant is not circulated. However, the refrigerant discharge pipe 52b extends downward from the stack case 54, and thus the refrigerant of the fuel cell stack 12 actively flows downward due to gravity. Then, for example, at the initial stage of the stop of the pump 58, the refrigerant circulating in the refrigerant pipe 52 continues to flow.

In response to such operation of the refrigerant during the stop of power generation, the valve element 62 (structure 60) provided in the refrigerant pipe 52 suppresses the flow of the refrigerant (see fig. 3A and 3B). Specifically, the supply-side valve body 62a of the refrigerant supply pipe 52a suppresses the refrigerant cooled by the cooling device 18 (the radiator 56, the pump 58, and the refrigerant pipe 52) from moving to the fuel cell stack 12. Conversely, the discharge-side valve body 62b of the refrigerant discharge pipe 52b suppresses the refrigerant warmed in the fuel cell stack 12 from moving to the outside. Accordingly, the fuel cell system 10 can reduce the rapid temperature drop of the fuel cell stack 12 at the initial stage of the power generation stop, and can keep the temperature of the fuel cell stack 12 at a constant level.

In particular, the valve body 62 located at the position of the wall portion 55 (the position near the end plate 30a) of the stack case 54 suppresses the flow of the refrigerant that has been reduced in temperature in the refrigerant pipe 52, and therefore, the fuel cell stack 12 can be kept warm more effectively. Further, during the stop of power generation, when the refrigerant in the fuel cell stack 12 flows backward (when the refrigerant is about to flow out to the refrigerant supply pipe 52a inclined downward), the valve body 62 of the refrigerant supply pipe 52a can prevent the refrigerant from flowing out by closing the opening/closing portion 72 of the valve body 62. Alternatively, for example, when the vehicle 11 is stopped on a slope or the like and the radiator 56 is in a high position and the refrigerant flows backward, the valve body 62 of the refrigerant discharge pipe 52b can prevent the refrigerant from flowing in by closing the opening/closing portion 72.

The present invention is not limited to the above-described embodiments, and various modifications can be made in accordance with the gist of the present invention. For example, a plurality of valve bodies 62 may be provided in the refrigerant supply pipe 52a and the refrigerant discharge pipe 52 b. The valve element 62 is not limited to the configuration in which the opening/closing portion 72 forms the gap 76 (the circulation-restricted state of the refrigerant) when the power generation is stopped, and may be configured to completely block the flow path of the refrigerant pipe 52 (the circulation-restricted state of the refrigerant is formed).

The structure 60 (valve element 62) is not limited to the above-described structure, and various structures can be applied. For example, the opening/closing portion 72 of the valve body 62 may be configured such that four or more sheets 74 are elastically deformed, or may be configured such that a pair of films are separated from and approach each other (a so-called duckbill valve). The valve body 62 may have a series of conical films connected in series, and the films may be opened to a large extent by the flow force of the refrigerant. Alternatively, the structure 60 may be a disk valve (japanese: ディスク, etc.) in which the opening/closing part 72 does not protrude.

As in the first modification shown in fig. 4A to 4D, the structure 60 may be a reed valve 80 having a hard portion 82 and a soft portion 84, the hard portion 82 may be formed in a conical shape, one or more mouth portions 82a may be provided on an inclined surface thereof, and a part of the soft portion 84 may be fixed to the hard portion 82 and may openably cover the mouth portions 82 a. The hard portion 82 has the same function as the fixing portion 70 in fig. 3 fixed to the inner surface of the refrigerant pipe 52. The soft portion 84 closes the port portion 82a (forms a blocked state against the refrigerant) when the refrigerant has no flow force, and is deformed by the flow force of the refrigerant to open the port portion 82a and allow the refrigerant to flow therethrough. This can obtain the same effect as the valve body 62 described above.

In addition, as in the case of the valve body 62, the reed valve 80 may be configured to form the gap 76 (flow-restricted state) between the port 82a and the soft portion 84 when there is no flow force of the refrigerant. Although fig. 4A to 4D (and fig. 5A to 5B) show a configuration in which the reed valve 80 (the blocking valve 92) is provided directly on the refrigerant pipe 52, it goes without saying that the reed valve 80 can be provided on the refrigerant pipe 52 using the relay pipe 68, similarly to the valve body 62 described above.

As in the second modification shown in fig. 5A and 5B, the structure 60 may be a ball valve 92a (a shutoff valve 92) driven by the actuator 90. The ball valve 92a includes a ball 94, and the ball 94 is rotatable in the flow passage of the refrigerant pipe 52 and has a through hole 94 a. The actuator 90 rotates the spherical body 94 under the control of the control device 20, and brings the flow path into a blocked state (or a blocked state) by causing the through hole 94a to not face the flow path, and brings the through hole 94a into a communicating state by causing the through hole to face the flow path.

The controller 20 switches the flow path between the interruption and the communication according to the temperature of the refrigerant in the refrigerant pipe 52, the temperature of the fuel cell stack 12, the temperature of the environment around the fuel cell system 10, the power generation state of the fuel cell, and the like. As an example, the control device 20 may be configured to allow the refrigerant to flow without shutting off the refrigerant pipe 52 immediately after the power generation is stopped when the temperature of the fuel cell stack 12 is high, and to shut off the refrigerant pipe 52 when the temperature of the fuel cell stack 12 is equal to or lower than a predetermined value.

The blocking valve 92 driven by the actuator 90 is not limited to the ball valve 92a, and may be, for example, a butterfly valve, a stop valve, or the like.

As in the third modification shown in fig. 6, the fuel cell system 10A may be configured to include pilot check valves 100 in the refrigerant supply pipe 52a and the refrigerant discharge pipe 52b, respectively. The check valve with pilot 100a provided in the refrigerant supply pipe 52a switches the refrigerant supply pipe 52a to open or close based on the flow path pressure of the refrigerant discharge pipe 52 b. On the other hand, the pilot check valve 100b provided in the refrigerant discharge pipe 52b opens or closes the refrigerant discharge pipe 52b based on the flow passage pressure of the refrigerant supply pipe 52 a. This allows the fuel cell system 10A to circulate the refrigerant when the channel pressure of the refrigerant pipe 52 is high, and to shut off the channel when the channel pressure is low, thereby maintaining the fuel cell stack 12 at a good temperature.

As in the fourth modification shown in fig. 7, the fuel cell system 10C may be provided with an auxiliary equipment case 110 that accommodates at least one of the components of the anode gas system device 14 and the cathode gas system device 16 at one end side of the stack case 54, and the structure 60 may be provided in the refrigerant piping 52 near the boundary of the auxiliary equipment case 110. Even if the auxiliary equipment case 110 includes the structural body 60 in this way, the fuel cell system 10C can block or suppress the flow of the refrigerant, as in the above-described embodiment. In particular, by providing the structure 60 at the boundary of the auxiliary device case 110, the refrigerant pipe 52 in the auxiliary device case 110 can be kept warm by heat released from the components and pipes of the reaction gas system.

The idea and effect of the technique that can be grasped according to the above-described embodiments are described below.

The

fuel cell systems

10, 10A to 10C include the structural body 60 at a position near the end plate 30A of the refrigerant pipe 52 (each of the refrigerant supply pipe 52a and the refrigerant discharge pipe 52b), and thereby can suppress or prevent the flow of the refrigerant in the refrigerant pipe 52 when the operation of the fuel cell stack 12 is stopped. That is, in the

fuel cell systems

10, 10A to 10C, the structure 60 suppresses the discharge of the refrigerant whose temperature has been increased from the fuel cell stack 12 or the supply of the refrigerant having a low temperature to the fuel cell stack 12, and therefore, the fuel cell stack 12 can be kept warm well. The chance of a sharp drop in the temperature of the fuel cell stack 12 is reduced, whereby the life thereof can be extended. Further, since the structure 60 can be easily installed in the refrigerant pipe 52 without complicating the system, the system can be downsized and the manufacturing cost can be reduced.

The fuel cell stack 12 includes a stack 24 in which a plurality of power generation cells 22 that generate power and end plates 30a are stacked, and a stack case 54 that houses the stack 24, and a structure 60 is provided at the boundary where the refrigerant piping 52 is exposed from the stack case 54. Thus, when the power generation of the fuel cell stack 12 is stopped, the refrigerant that has been cooled in the refrigerant pipe 52 exposed outside the stack case 54 is prevented from flowing into the stack case 54. Therefore, the fuel cell stack 12 can be kept warm more favorably.

Further, the structure 60 is provided in the relay pipe 68 provided between the plurality of pipes constituting the refrigerant pipe 52, thereby constituting the pipe unit 69. This allows the

fuel cell systems

10 and 10A to 10C to be provided with the structure 60 in the refrigerant piping 52 in a simple manner, and also allows maintenance and the like to be simplified.

The structure 60 is a valve body 62 fixed to the inner circumferential surface of the refrigerant pipe 52 and having a large opening as the refrigerant flows. Thus, the

fuel cell systems

10, 10A to 10C can simplify the structure of the structural body 60 and suppress or prevent the flow of the refrigerant through the refrigerant pipe 52.

The structure 60 is a pilot check valve 100 that opens and closes based on the flow passage pressure of the refrigerant pipe 52. By providing the pilot-operated check valve 100 that opens and closes based on the flow path pressure of the refrigerant pipe 52 in this manner, the fuel cell system 10A can more reliably switch the refrigerant flow state through the refrigerant pipe 52.

The structure 60 is a shutoff valve 92 driven by the actuator 90. Thereby, the

fuel cell systems

10, 10A to 10C can control the actuator 90 and suppress or block the flow of the refrigerant at a desired timing.

In addition, another embodiment of the present invention relates to a method for adjusting the temperature of the fuel cell stack 12, wherein a refrigerant pipe 52 for circulating a refrigerant is connected to the end plate 30a of the fuel cell stack 12, the refrigerant pipe 52 includes a refrigerant supply pipe 52a for supplying the refrigerant to the fuel cell stack 12, a refrigerant discharge pipe 52b for discharging the refrigerant from the fuel cell stack 12, and a pump 58 for circulating the refrigerant, a structure 60 is provided in the vicinity of the end plate 30a of each of the refrigerant supply pipe 52a and the refrigerant discharge pipe 52b, when the fuel cell stack 12 generates power, the pump 58 is driven to set a state in which the coolant flows through the structure 60, thereby cooling the fuel cell stack 12, when the power generation of the fuel cell stack 12 is stopped, the heat retention state of the fuel cell stack 12 is maintained by stopping the driving of the pump 58 and setting the structure 60 to the flow-restricted state or the flow-blocked state. Thus, the

fuel cell systems

10 and 10A to 10C can allow the coolant to flow well when the fuel cell stack 12 generates power without complicating the systems, and can reduce the temperature drop of the fuel cell stack 12 when the power generation of the fuel cell stack 12 is stopped.

Claims

1. A fuel cell system is provided with: a fuel cell stack (12), and a refrigerant pipe (52) connected to an end plate (30A) of the fuel cell stack and through which a refrigerant flows, wherein in the fuel cell system (10, 10A to 10C),

the refrigerant piping includes a refrigerant supply piping (52a) for supplying the refrigerant to the fuel cell stack, and a refrigerant discharge piping (52b) for discharging the refrigerant from the fuel cell stack,

a structure (60) for suppressing or preventing the flow of the refrigerant is provided in the vicinity of the end plate of each of the refrigerant supply pipe and the refrigerant discharge pipe.

2. The fuel cell system according to claim 1,

the fuel cell stack includes: a laminate (24) in which a plurality of power generation cells (22) that generate power and the end plates are laminated, and a stack case (54) that houses the laminate,

the structural body is provided at a boundary where the refrigerant pipe is exposed from the stack case.

3. The fuel cell system according to claim 1 or 2,

the structure is provided in a relay pipe (68) provided between a plurality of pipes constituting the refrigerant pipe, thereby constituting a pipe unit (69).

4. The fuel cell system according to claim 1,

the structure is a valve body (62) that is fixed to the inner circumferential surface of the refrigerant pipe and has a large opening as the refrigerant flows.

5. The fuel cell system according to claim 1,

the structure is a one-way valve (100, 100a, 100b) with a pilot type that opens and closes based on the flow path pressure of the refrigerant pipe.

6. The fuel cell system according to claim 1,

the structure is a block valve (92) driven by an actuator.

7. A method for adjusting the temperature of a fuel cell stack (12) in which a refrigerant pipe (52) for circulating a refrigerant is connected to an end plate (30a) of the fuel cell stack,

the refrigerant pipe includes: a refrigerant supply pipe (52a) for supplying the refrigerant to the fuel cell stack, a refrigerant discharge pipe (52b) for discharging the refrigerant from the fuel cell stack, and a pump (58) for circulating the refrigerant,

a structural body (60) is provided in the vicinity of the end plate of each of the refrigerant supply pipe and the refrigerant discharge pipe,

driving the pump to set a state in which the coolant flows through the structure when the fuel cell stack generates power, thereby cooling the fuel cell stack,

when the power generation of the fuel cell stack is stopped, the heat retention state of the fuel cell stack is maintained by stopping the driving of the pump and setting the structure to a state in which the flow of the coolant is suppressed or a state in which the flow of the coolant is blocked.