JP2020149933A - Fuel cell system and temperature adjusting method thereof - Google Patents

Abstract

To provide a fuel cell system and a temperature adjusting method thereof that reduces the temperature drop of the fuel cell stack while suppressing the complexity of the system.SOLUTION: A fuel cell system 10 includes a fuel cell stack 12 and a refrigerant pipe 52 connected to an end plate 30a of the fuel cell stack 12 and circulating refrigerant. The refrigerant pipe 52 includes a refrigerant supply pipe 52a that supplies refrigerant to the fuel cell stack 12, and a refrigerant discharge pipe 52b that discharges the refrigerant from the fuel cell stack 12. A structure 60 is provided near each end plate 30a of the refrigerant supply pipe 52a and the refrigerant discharge pipe 52b. In the temperature adjusting method of the fuel cell stack 12, the heat retention state of the fuel cell stack 12 is maintained by putting the refrigerant in the flow suppression state or the distribution blocking state by the structure 60.SELECTED DRAWING: Figure 2

Description

The present invention relates to a fuel cell system having a cooling pipe for flowing a refrigerant through the fuel cell stack, and a method for adjusting the temperature of the fuel cell stack.

The fuel cell system generates electricity in the fuel cell stack by circulating (supplying and discharging) anode gas and cathode gas through a reaction gas pipe connected to the fuel cell stack. Further, as shown in Patent Document 1, the fuel cell system adjusts the temperature of the fuel cell stack during power generation by circulating the refrigerant through a refrigerant pipe connected to the fuel cell stack.

Japanese Unexamined Patent Publication No. 2006-147315

By the way, when the temperature of the fuel cell stack drops sharply after the power generation is stopped, the energy required for starting the fuel cell stack becomes large when the operation is restarted at an early stage thereafter. Further, the fuel cell stack deteriorates and shortens its life when there are many opportunities for a sudden temperature drop. Therefore, the fuel cell system disclosed in Patent Document 1 is provided with a heat storage device for heating the refrigerant to keep the fuel cell stack warm when power generation is stopped.

However, in the configuration provided with the heat storage device as in the fuel cell system disclosed in Patent Document 1, the system becomes complicated, and inconveniences 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 technology, and is a fuel cell capable of reducing the temperature drop of the fuel cell stack due to the flow of the refrigerant after the power generation is stopped while suppressing the complexity of the system. It is an object of the present invention to provide a method for adjusting the temperature of a system and a fuel cell stack.

In order to achieve the above object, the first aspect of the present invention is a fuel cell system including a fuel cell stack and a refrigerant pipe connected to an end plate of the fuel cell stack to allow a refrigerant to flow. The refrigerant pipe includes a refrigerant supply pipe that supplies the refrigerant to the fuel cell stack and a refrigerant discharge pipe that discharges the refrigerant from the fuel cell stack, and each of the refrigerant supply pipe and the refrigerant discharge pipe. A structure for suppressing or blocking the flow of the refrigerant is provided near the end plate.

Further, in order to achieve the above object, the second aspect of the present invention is 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, wherein the refrigerant pipe is the fuel. Each of the refrigerant supply pipe and the refrigerant discharge pipe includes a refrigerant supply pipe for supplying the refrigerant to the battery 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 near the end plate, and when the fuel cell stack is generating power, the pump is driven and the refrigerant is circulated through the structure to cool the fuel cell stack. When the power generation of the fuel cell stack is stopped, the driving of the pump is stopped, and the structure keeps the refrigerant in a flow suppressing state or a flow blocking state to maintain the heat retention state of the fuel cell stack.

By providing the structure in the vicinity of the end plate of the refrigerant pipe, the above fuel cell system can suppress or prevent the flow of the refrigerant in the refrigerant pipe when the operation of the fuel cell stack is stopped. That is, in the fuel cell system, the discharge of the heated refrigerant from the fuel cell stack or the supply of the low temperature refrigerant to the fuel cell stack is suppressed by the structure, so that it is possible to reduce the temperature drop of the fuel cell stack. It becomes. The life of a fuel cell stack can be extended by reducing the chances of a sudden temperature drop. Moreover, since the structure is easily provided in the refrigerant pipe without complicating the system, the system can be miniaturized and the manufacturing cost can be reduced.

It is explanatory drawing which shows schematic the whole structure of the fuel cell system which concerns on one Embodiment of this invention. It is explanatory drawing which shows schematic structure of a fuel cell stack and a cooling device. FIG. 3A is a cross-sectional view showing a state in which the flow of the refrigerant is suppressed by the valve body provided in the refrigerant pipe. FIG. 3B is a sectional view taken along line IIIB-IIIB of FIG. 3A. FIG. 3C is a cross-sectional view showing a flow state of the refrigerant by the valve body provided in the refrigerant pipe. FIG. 3D is a sectional view taken along line IIID-IIID of FIG. 3C. FIG. 4A is a cross-sectional view showing a state in which the flow of the refrigerant is cut off by the lead valve according to the first modification. FIG. 4B is a sectional view taken along line IVB-IVB of FIG. 4A. FIG. 4C is a cross-sectional view showing a flow state of the refrigerant by the lead 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 state in which the flow of the refrigerant is cut off by the cutoff valve according to the second modification. FIG. 5B is a cross-sectional view showing a flow state of the refrigerant by the shutoff valve of FIG. 5A. It is explanatory drawing which shows schematicly about the whole structure of the fuel cell system which concerns on 3rd modification. It is explanatory drawing which shows typically the fuel cell stack of the fuel cell system which concerns on 4th modification and the peripheral part thereof.

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

As shown in FIG. 1, the fuel cell system 10 according to the 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 vehicle (vehicle 11).

The fuel cell stack 12 generates electricity based on the anode gas (fuel gas such as hydrogen) supplied from the anode gas system device 14 and the cathode gas (oxidizer gas such as air) supplied from the cathode gas system device 16. Do. Further, the cooling device 18 supplies the refrigerant (cooling water or the like) to the fuel cell stack 12 at the time of power generation of the fuel cell stack 12, and discharges the refrigerant from the fuel cell stack 12 to cool the fuel cell stack 12 (cooling water). Temperature adjustment).

As shown in FIG. 2, the fuel cell stack 12 has a plurality of power generation cells 22 that generate power by an electrochemical reaction between an anode gas and a cathode gas. The plurality of power generation cells 22 are configured in a laminated body 24 in which the fuel cell stack 12 is mounted on the vehicle 11 and laminated along the vehicle width direction with the electrode surface in a standing posture. Terminal plates 26a and 26b, insulating plates 28a and 28b, and end plates 30a and 30b are laminated in this order on both ends of the laminated body 24 in the stacking direction. The plurality of power generation cells 22 may be stacked in the front-rear direction or the gravity direction of the vehicle 11.

The power generation cell 22 is composed of an electrolyte membrane / electrode structure 32 (hereinafter referred to as “MEA32”) and two separators 34 sandwiching the MEA32. The separators 34 of the adjacent power generation cells 22 are joined to each other to form an integral joining separator.

The MEA 32 of the power generation cell 22 includes an electrolyte membrane 36 (for example, a solid polymer electrolyte membrane (cation exchange membrane)), an anode electrode 38 provided on one surface of the electrolyte membrane 36, and the other surface of the electrolyte membrane 36. It has a cathode electrode 40 provided in. The two separators 34 form an anode gas flow path 38a for flowing the anode gas and a cathode gas flow path 40a for flowing the cathode gas on each of the surfaces facing the MEA 32. Further, a refrigerant flow path 42 for flowing the refrigerant is formed on the surface where the two separators 34 face each other.

Further, the laminated body 24 has a plurality of communication holes (anode gas communication hole 44, cathode gas communication hole 46, refrigerant communication hole 48) for individually flowing the anode gas, the cathode gas and the refrigerant along the stacking direction of the power generation cell 22. ) Is provided. In the laminate 24, the anode gas communication hole 44 communicates with the anode gas flow path 38a, the cathode gas communication hole 46 communicates with the cathode gas flow path 40a, and the refrigerant communication hole 48 communicates with the refrigerant flow path 42. ..

The anode gas supplied to the laminate 24 flows through the anode gas communication hole 44 (anode gas inlet communication hole 44a) and flows into the anode gas flow path 38a. The anode off gas used for power generation in the anode electrode 38 flows into the anode gas communication hole 44 (anode gas outlet communication hole 44b) from the anode gas flow path 38a and is discharged from the laminate 24.

The cathode gas supplied to the laminate 24 flows through the cathode gas communication hole 46 (cathode gas inlet communication hole 46a) and flows into the cathode gas flow path 40a. The cathode off gas used for power generation in the cathode electrode 40 flows into the cathode gas communication hole 46 (cathode gas outlet communication hole 46b) from the cathode gas flow path 40a and is discharged from the laminate 24.

The refrigerant supplied to the laminated body 24 flows through the refrigerant communication hole 48 (refrigerant inlet communication hole 48a) and flows into the refrigerant flow path 42. The refrigerant that has cooled the power generation cell 22 flows into the refrigerant communication hole 48 (refrigerant outlet communication hole 48b) from the refrigerant flow path 42 and is discharged from the laminated body 24.

A reaction 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 laminated body 24. The reaction gas pipe 50 includes an anode gas supply pipe 50a communicating with the anode gas inlet communication hole 44a, an anode gas discharge pipe 50b communicating with the anode gas outlet communication hole 44b, and a cathode gas supply pipe 50c communicating with the cathode gas inlet communication hole 46a. And the cathode gas discharge pipe 50d communicating with the cathode gas outlet communication hole 46b. The refrigerant pipe 52 has a refrigerant supply pipe 52a communicating with the refrigerant inlet communication hole 48a and a refrigerant discharge pipe 52b communicating with the refrigerant outlet communication hole 48b.

Further, the fuel cell stack 12 includes a stack case 54 that accommodates the entire laminated body 24 including the end plates 30a and 30b in the space portion 54a. The stack case 54 may be formed in a tubular body that surrounds the laminated body 24 of the power generation cell 22 that is orthogonal to the stacking direction, and the end portions of the tubular body may be closed by end plates 30a and 30b.

The above reaction gas pipe 50 (anode gas supply pipe 50a, anode gas discharge pipe 50b, cathode gas supply pipe 50c, cathode gas discharge pipe 50d) and refrigerant pipe 52 (hydrogen supply pipe 52a, refrigerant discharge) connected to the end plate 30a. The pipe 52b) penetrates the wall portion 55 on one end side of the stack case 54 and is exposed to the outside of the stack case 54. Packing or the like may be provided at the through portion of the pipe of the stack case 54.

As shown in FIGS. 1 and 2, the cooling device 18 of the fuel cell system 10 forms a circulation circuit for circulating the refrigerant between the fuel cell stack 12 and the fuel cell stack 12 by the refrigerant pipe 52, the radiator 56, and the pump 58. ing. Specifically, the refrigerant supply pipe 52a extends between the laminated body 24 (end plate 30a) and the radiator 56, and is provided with a pump 58 at an intermediate position thereof. The refrigerant discharge pipe 52b extends between the laminated body 24 (end plate 30a) and the radiator 56.

The 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 gravity direction. Therefore, when the refrigerant pipe 52 (refrigerant supply pipe 52a, refrigerant discharge pipe 52b) is exposed from the wall portion 55 of the stack case 54, the refrigerant pipe 52 is curved at a position close to the wall portion 55 and extends forward and downward. .. The material constituting the refrigerant pipe 52 is not particularly limited, and either a metal material or a resin material may be applied.

The radiator 56 is composed of, for example, an internal pipe (not shown) in which the refrigerant flows through the refrigerant pipe 52 and a radiator fan 56a, and cools the refrigerant in the internal pipe by cooling air accompanying the rotation of the radiator fan 56a. To do. Needless to say, the configuration and installation position of the radiator 56 are not particularly limited.

The operation of the pump 58 is controlled by the control device 20, and the refrigerant in the refrigerant supply pipe 52a is circulated to supply the refrigerant to the fuel cell stack 12. As a result, the refrigerant of the fuel cell stack 12 also flows out to the refrigerant discharge pipe 52b and flows to the radiator 56 based on the flow. The cooling device 18 may include a pump 58 in the refrigerant discharge pipe 52b instead of the refrigerant supply pipe 52a, or may provide a pump 58 in each of the refrigerant supply pipe 52a and the refrigerant discharge pipe 52b.

In addition to the above devices, the cooling device 18 may be provided with various devices (not shown). For example, the device of the cooling device 18 includes an ion exchanger that removes ions contained in the refrigerant, a reserve tank that stores the refrigerant, a temperature sensor that detects the temperature of the refrigerant, and the like. Further, the extending directions of the refrigerant supply pipe 52a and the refrigerant discharge pipe 52b can be appropriately designed. A bypass pipe (not shown) that bypasses the radiator 56 may be provided between the refrigerant supply pipe 52a and the refrigerant discharge pipe 52b.

Then, the fuel cell system 10 has a structure 60 that suppresses the flow of the refrigerant in the refrigerant pipe 52 (in a distribution restrained state) 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 52b.

Further, the structure 60 is provided at a position near the end plate 30a of the fuel cell stack 12. The "near position" of the end plate 30a means that the end plate 30a is closer to the end plate 30a than the intermediate position of the refrigerant pipe 52 extending between the end plate 30a and the device (radiator 56, pump 58, etc.) of the cooling device 18. .. For example, the vicinity position is in a range of about 30 cm or less from the connection point between the end plate 30a and the refrigerant pipe 52. The structure 60 according to the present embodiment is provided at the boundary of the stack case 54, so that the structure 60 is sufficiently close to the end plate 30a.

The structure 60 according to the present embodiment is configured as a valve body 62 that does not completely shut off the flow path of the refrigerant pipe 52 (partially opens the flow path) when the flow of the refrigerant is stopped. Hereinafter, the valve body 62 and the refrigerant pipe 52 in which the valve body 62 is arranged will be described with reference to FIGS. 3A to 3D.

The refrigerant pipe 52 is configured in a divided structure of a plurality of pipes (first pipe 64, second pipe 66), and is connected between the first pipe 64 and the second pipe 66 by a relay pipe 68 to which the valve body 62 is fixed. are doing. That is, the valve body 62 and the relay pipe 68 form a pipe unit 69 for providing the valve body 62 at an intermediate position of the refrigerant pipe 52.

The pipe unit 69 is provided at a position overlapping the wall portion 55 on one end side of the stack case 54, and for example, a packing is installed between the wall portion 55 and the relay pipe 68. The relay pipe 68 may be connected to the wall portion 55 of the stack case 54. Further, the "boundary" of the stack case 54 includes a portion overlapping the wall portion 55 of the stack case 54, as well as a portion adjacent to the wall portion 55 on the outside or inside of the wall portion 55 of the stack case 54. For example, when the first pipe 64 is inside the stack case 54 and the second pipe 66 is outside the stack case 54, the relay pipe 68 is configured as a connector protruding from the stack case 54 to connect the second pipe 66. It may have been done.

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

The fixing portion 70 is formed in an annular shape and is closely fixed to the inner peripheral surface of the relay pipe 68 by an appropriate fixing means. The fixing means is not particularly limited, and means such as fusion, adhesion, and internal fitting of other fixing members may be taken. Alternatively, the relay pipe 68 and the valve body 62 may have a structure in which a locked portion (concave portion, convex portion, etc.) (not shown) is provided on one side and a locking portion locked to the locked portion is provided on the other side. ..

The opening / closing portion 72 is composed of a plurality of (three in the illustrated example) flakes 74. Each thin piece 74 projects from one end of the fixing portion 70 in an inclined manner toward the center of the relay pipe 68, so that the entire opening / closing portion 72 has a substantially conical shape. The direction in which the opening / closing portion 72 protrudes from the fixing portion 70 is the direction in which the refrigerant flows from upstream to downstream in the flow direction. Therefore, in the refrigerant supply pipe 52a, the supply side valve body 62a is arranged so that the opening / closing portion 72 protrudes toward the end plate 30a, and in the refrigerant discharge pipe 52b, the opening / closing portion 72 protrudes toward the radiator 56. The discharge side valve body 62b is arranged.

Each slice 74 is formed in a triangular shape obtained by dividing the substantially conical shape of the opening / closing portion 72. Each slice 74 is elastically deformed on the protruding end side to the base point of the fixing portion 70 based on the flow force of the refrigerant. Further, the protruding ends of the thin sections 74 in the present embodiment are separated from each other, and a gap 76 is formed between the protruding ends.

Each of the above-mentioned flakes 74 stops the flow of the refrigerant when the power generation of the fuel cell stack 12 is stopped, so that the refrigerant hardly passes close to each other. However, the communication of the flow path is maintained by slightly flowing the refrigerant from the gap 76 (the flow of the refrigerant is suppressed). Further, each of the flakes 74 operates so as to close the gap 76 when the refrigerant flows in the direction opposite to that at the time of distribution. Further, each of the flakes 74 is largely separated from each other during power generation (during the flow of the refrigerant) of the fuel cell stack 12, so that an appropriate amount of the refrigerant flows.

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

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

As shown in FIG. 1, in the fuel cell system 10, under the control of the control device 20, the anode gas system device 14 supplies the anode gas to the fuel cell stack 12, and the cathode system device supplies the cathode gas to the fuel cell stack 12. Supply. In the fuel cell stack 12, as shown in FIG. 2, 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. Each power generation cell 22 generates power. Further, the fuel cell system 10 discharges the anode off gas during power generation from the fuel cell stack 12 to the anode gas system device 14, and discharges the cathode off gas during power generation from the fuel cell stack 12 to the cathode gas system device 16.

Then, when the fuel cell stack 12 generates electricity, the fuel cell system 10 appropriately drives the pump 58 under the control of the control device 20 to circulate the refrigerant between the fuel cell stack 12 and the cooling device 18 to circulate the fuel cell. Cool the stack 12. That is, the cooling device 18 supplies the refrigerant to the fuel cell stack 12 through the flow path of the refrigerant supply pipe 52a. In the supply side valve body 62a provided in the refrigerant supply pipe 52a, the opening / closing portion 72 (plurality of thin pieces 74) is greatly opened with the flow force of the refrigerant toward the laminated body 24 to allow the refrigerant to flow smoothly (FIG. FIG. See 3C and FIG. 3D).

In the fuel cell stack 12, the refrigerant supplied from the refrigerant supply pipe 52a cools each power generation cell 22 by passing through the refrigerant flow path 42 between the adjacent separators 34. Then, the fuel cell system 10 discharges the heated refrigerant from the fuel cell stack 12 to the radiator 56 through the flow path of the refrigerant discharge pipe 52b. At this time, in the discharge side valve body 62b provided in the refrigerant discharge pipe 52b, the opening / closing portion 72 (plurality of thin pieces 74) opens widely with the flow force of the refrigerant toward the radiator 56 to allow the refrigerant to flow smoothly. .. Then, the radiator 56 cools the refrigerant under the drive of the radiator fan 56a.

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. When the pump 58 of the cooling device 18 is stopped, the refrigerant does not circulate. However, since the refrigerant discharge pipe 52b extends downward from the stack case 54, the refrigerant in the fuel cell stack 12 tends to actively flow downward due to gravity. Further, for example, the flow of the refrigerant circulating in the refrigerant pipe 52 continues at the initial stage of stopping the pump 58.

The valve body 62 (structure 60) provided in the refrigerant pipe 52 suppresses the flow of the refrigerant against the movement of the refrigerant when the power generation is stopped (see FIGS. 3A and 3B). Specifically, the supply-side valve body 62a of the refrigerant supply pipe 52a suppresses the movement of the refrigerant cooled by the cooling device 18 (radiator 56, pump 58, refrigerant pipe 52) to the fuel cell stack 12. On the contrary, the discharge side valve body 62b of the refrigerant discharge pipe 52b suppresses the movement of the warmed refrigerant in the fuel cell stack 12 to the outside. Therefore, the fuel cell system 10 can reduce the sudden temperature drop of the fuel cell stack 12 at the initial stage of power generation stoppage and keep the fuel cell stack 12 warm.

In particular, the valve body 62 located at the wall portion 55 (position near the end plate 30a) of the stack case 54 suppresses the flow of the cooled refrigerant in the refrigerant pipe 52, so that the heat retention of the fuel cell stack 12 is more effective. Can be done Further, the valve body 62 of the refrigerant supply pipe 52a is used when the refrigerant in the fuel cell stack 12 flows backward (when the refrigerant tries to flow out to the downwardly inclined refrigerant supply pipe 52a) while the power generation is stopped. By closing the opening / closing portion 72 of the valve body 62, the outflow of the refrigerant can be prevented. Alternatively, the valve body 62 of the refrigerant discharge pipe 52b also causes the inflow of the refrigerant by closing the opening / closing portion 72 when the radiator 56 is in a high position and the refrigerant flows backward, for example, when the vehicle 11 stops on a slope or the like. Can be prevented.

The present invention is not limited to the above embodiment, and various modifications can be made according to the gist of the invention. For example, a plurality of valve bodies 62 may be provided in the refrigerant supply pipe 52a and the refrigerant discharge pipe 52b. Further, the valve body 62 is not limited to the configuration in which the opening / closing portion 72 forms the gap 76 (refrigerant flow restrained state) as described above when the power generation is stopped, and completely shuts off the flow path of the refrigerant pipe 52 (refrigerant). It may be configured (to form a distribution blocking state).

Further, the structure 60 (valve body 62) is not limited to the above configuration, and various configurations can be applied. For example, the opening / closing portion 72 of the valve body 62 may have a configuration in which four or more flakes 74 are elastically deformed, or a configuration in which a pair of membranes are separated from each other and close to each other (so-called duck bill valve). Further, the valve body 62 may have a series of conical membranes, and the membrane may be greatly opened by the flow force of the refrigerant. Alternatively, the structure 60 may be fitted with a disc valve or the like in which the opening / closing portion 72 does not protrude.

Further, as in the first modification shown in FIGS. 4A to 4D, the structure 60 is formed in a conical shape, and the hard portion 82 having one or more mouth portions 82a on its inclined surface and the hard portion 82 are one. The lead valve 80 may have a soft portion 84 to which the portion is fixed and covers the mouth portion 82a so as to be openable and closable. The hard portion 82 has the same function as the fixing portion 70 in FIG. 3 which is fixed to the inner surface of the refrigerant pipe 52. The soft portion 84 closes the mouth portion 82a (forms a state in which the flow of the refrigerant is blocked) when the refrigerant has no flow force, while the soft portion 84 is deformed by the flow force of the refrigerant to open the mouth portion 82a and flow the refrigerant. Let me. As a result, the same effect as that of the valve body 62 can be obtained.

Similar to the valve body 62, the lead valve 80 may have a configuration in which a gap 76 (flow restrained state) is formed between the mouth portion 82a and the soft portion 84 when the refrigerant has no fluidity. Further, FIGS. 4A to 4D (and FIGS. 5A to 5B) show a configuration in which the lead valve 80 (cutoff valve 92) is directly installed in the refrigerant pipe 52, but the lead valve 80 is similar to the valve body 62. Of course, the relay pipe 68 can be applied and installed in the refrigerant pipe 52.

Further, as in the second modification shown in FIGS. 5A and 5B, the structure 60 may be a ball valve 92a (cutoff valve 92) driven by the actuator 90. The ball valve 92a includes a sphere 94 that is rotatable in the flow path of the refrigerant pipe 52 and has a through hole 94a. The actuator 90 rotates the sphere 94 under the control of the control device 20 to prevent the through hole 94a from facing the flow path, thereby putting the flow path in the flow blocking state (or the flow suppressing state) and making the through hole 94a face the flow path. By letting it communicate, it becomes a state of communication.

The control device 20 switches between shutting off and communicating with the flow path according to the temperature of the refrigerant in the refrigerant pipe 52, the temperature of the fuel cell stack 12, the temperature of the ambient environment of the fuel cell system 10, the power generation state of the fuel cell, and the like. As an example, when the temperature of the fuel cell stack 12 is high, the control device 20 allows the refrigerant to flow without interrupting the refrigerant pipe 52 immediately after the power generation is stopped, and when the temperature of the fuel cell stack 12 becomes equal to or lower than a predetermined value. The refrigerant pipe 52 can be cut off.

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

As in the third modification shown in FIG. 6, the fuel cell system 10A may be configured to include a check valve 100 with a pilot in each of the refrigerant supply pipe 52a and the refrigerant discharge pipe 52b. The check valve 100a with a pilot provided in the refrigerant supply pipe 52a switches between opening and closing of the refrigerant supply pipe 52a based on the flow path pressure of the refrigerant discharge pipe 52b. On the other hand, the check valve 100b with a pilot provided in the refrigerant discharge pipe 52b switches between opening and closing of the refrigerant discharge pipe 52b based on the flow path pressure of the refrigerant supply pipe 52a. As a result, the fuel cell system 10A can circulate the refrigerant when the flow path pressure of the refrigerant pipe 52 is high and shut off the flow path when the flow path pressure is low, and also keeps the fuel cell stack 12 well warm. can do.

Further, as in the fourth modification shown in FIG. 7, the fuel cell system 10C is an auxiliary machine in which at least one device of the anode gas system device 14 and the cathode gas system device 16 is housed on one end side of the stack case 54. The case 110 may be provided, and the structure 60 may be provided in the refrigerant pipe 52 near the boundary of the auxiliary machine case 110. As described above, even if the auxiliary machine case 110 is provided with the structure 60, the fuel cell system 10C can block or suppress the flow of the refrigerant as in the above embodiment. In particular, by providing the structure 60 at the boundary of the auxiliary machine case 110, the refrigerant pipe 52 in the auxiliary machine case 110 can be kept warm by the heat released from the reaction gas system device or the pipe.

The technical ideas and effects that can be grasped from the above embodiments are described below.

The fuel cell systems 10 and 10A to 10C are provided with a structure 60 near the end plate 30a of the refrigerant pipes 52 (refrigerant supply pipes 52a and refrigerant discharge pipes 52b) when the operation of the fuel cell stack 12 is stopped. , The flow of the refrigerant in the refrigerant pipe 52 can be suppressed or blocked. That is, in the fuel cell systems 10, 10A to 10C, the discharge of the heated refrigerant from the fuel cell stack 12 or the supply of the low-temperature refrigerant to the fuel cell stack 12 is suppressed by the structure 60, so that the fuel cell stack 12 Can be kept warm well. The life of the fuel cell stack 12 can be extended by reducing the chance of a sudden temperature drop. Moreover, since the structure 60 is easily provided in the refrigerant pipe 52 without complicating the system, it is possible to reduce the size of the system and the manufacturing cost.

Further, the fuel cell stack 12 includes a laminated body 24 in which a plurality of power generation cells 22 for generating power and an end plate 30a are laminated, and a stack case 54 for accommodating the laminated body 24, and the structure 60 is from the stack case 54. It is provided at the boundary where the refrigerant pipe 52 is exposed. As a result, when the power generation of the fuel cell stack 12 is stopped, the low temperature refrigerant in the refrigerant pipe 52 exposed to the outside of the stack case 54 is suppressed from flowing into the stack case 54. Therefore, the fuel cell stack 12 can be kept warm even better.

Further, the structure 60 is configured in the pipe unit 69 by being provided in the relay pipe 68 installed between the plurality of pipes constituting the refrigerant pipe 52. As a result, in the fuel cell systems 10, 10A to 10C, the structure 60 can be easily installed in the refrigerant pipe 52, and maintenance and the like can be simplified.

Further, the structure 60 is a valve body 62 that is fixed to the inner peripheral surface of the refrigerant pipe 52 and opens greatly with the flow of the refrigerant. Thereby, the fuel cell systems 10, 10A to 10C can suppress or prevent the flow of the refrigerant in the refrigerant pipe 52 while further simplifying the configuration of the structure 60.

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

Further, the structure 60 is a shutoff valve 92 driven by the actuator 90. As a result, the fuel cell systems 10, 10A to 10C can control the actuator 90 to suppress or shut off the flow of the refrigerant at a desired timing.

Another aspect of the present invention is a method for adjusting the temperature of the fuel cell stack 12 in which the refrigerant pipe 52 for circulating the refrigerant is connected to the end plate 30a, and the refrigerant pipe 52 supplies the refrigerant to the fuel cell stack 12. Refrigerant supply pipe 52a, a refrigerant discharge pipe 52b for discharging the refrigerant from the fuel cell stack 12, and a pump 58 for circulating the refrigerant, and a position near each end plate 30a of the refrigerant supply pipe 52a and the refrigerant discharge pipe 52b. Is provided with a structure 60, and when the fuel cell stack 12 is generating power, the pump 58 is driven and the refrigerant is circulated through the structure 60 to cool the fuel cell stack 12 and generate power from the fuel cell stack 12. When stopped, the drive of the pump 58 is stopped, and the structure 60 is placed in the flow suppression state or the flow prevention state to maintain the heat retention state of the fuel cell stack 12. As a result, the fuel cell systems 10 and 10A to 10C satisfactorily distribute the refrigerant when the fuel cell stack 12 generates power without complicating the system, while the fuel cell stack 12 stops the power generation of the fuel cell stack 12. It is possible to reduce the temperature drop of.

10, 10A to 10C ... Fuel cell system 12 ... Fuel cell stack 18 ... Cooling device 22 ... Power generation cell 24 ... Stacked body 30a, 30b ... End plate 52 ... Refrigerator pipe 52a ... Refrigerator supply pipe 52b ... Refrigerator discharge pipe 54 ... Stack case 55 ... Wall 60 ... Structure 62 ... Valve 68 ... Relay pipe 69 ... Pipe unit 74 ... Thin piece 80 ... Lead valve 90 ... Actuator 92 ... Shutoff valve 92a ... Ball valve 100, 100a, 100b ... Check valve with pilot

Claims (7)

With the fuel cell stack,
A fuel cell system including a refrigerant pipe connected to an end plate of the fuel cell stack and for circulating a refrigerant.
The refrigerant pipe includes a refrigerant supply pipe that supplies the refrigerant to the fuel cell stack and a refrigerant discharge pipe that discharges the refrigerant from the fuel cell stack.
A fuel cell system in which a structure for suppressing or blocking the flow of the refrigerant is provided at a position in the vicinity of the end plate of each of the refrigerant supply pipe and the refrigerant discharge pipe. In the fuel cell system according to claim 1,
The fuel cell stack includes a stack of a plurality of power generation cells for generating power and the end plates, and a stack case for accommodating the stack.
The structure is a fuel cell system provided at a boundary where the refrigerant pipe is exposed from the stack case. In the fuel cell system according to claim 1 or 2.
The structure is a fuel cell system configured in a pipe unit by being provided in a relay pipe installed between a plurality of pipes constituting the refrigerant pipe. In the fuel cell system according to any one of claims 1 to 3.
A fuel cell system in which the structure is fixed to the inner peripheral surface of the refrigerant pipe and opens widely with the flow of the refrigerant. In the fuel cell system according to any one of claims 1 to 3.
The structure is a fuel cell system that is a check valve with a pilot that opens and closes based on the flow path pressure of the refrigerant pipe. In the fuel cell system according to any one of claims 1 to 3.
The structure is a fuel cell system that is a shutoff valve driven by an actuator. It is a method of adjusting the temperature of the fuel cell stack in which the refrigerant piping for circulating the refrigerant is connected to the end plate.
The refrigerant pipe includes a refrigerant supply pipe that supplies the refrigerant to the fuel cell stack, a refrigerant discharge pipe that discharges the refrigerant from the fuel cell stack, and a pump that circulates the refrigerant.
A structure is provided in the vicinity of the end plate of each of the refrigerant supply pipe and the refrigerant discharge pipe.
At the time of power generation of the fuel cell stack, the fuel cell stack is cooled by driving the pump and circulating the refrigerant through the structure.
When the power generation of the fuel cell stack is stopped, the driving of the pump is stopped, and the structure keeps the fuel cell stack in a heat-retaining state by putting the refrigerant in a flow suppression state or a flow prevention state. Temperature adjustment method.

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