JP4781655B2 - Fuel cell system and control method of fuel cell system - Google Patents

Description

  The present invention relates to a fuel cell system and a control method for the fuel cell system. In particular, the present invention relates to a fuel cell system including a fuel cell that consumes hydrogen produced by a reformer and generates electric power, and a control method for the fuel cell system.

In a distributed power source using a fuel cell, a fuel reforming type fuel cell system is known. A fuel reforming type fuel cell system includes a reformer that generates hydrogen by reforming kerosene, city gas, propane gas, and the like, and supplies the hydrogen generated by the reformer to the fuel cell (for example, a patent) Reference 1).
JP 2001-185182 A

  By the way, when supplying the hydrogen produced by the reformer to the fuel cell, the fuel cell discharges off-gas containing unused hydrogen and carbon monoxide having a low purity of about 10% to 20%. In the conventional fuel cell system, the off gas discharged from the fuel cell is burned by the reformer.

  However, when producing hydrogen to be supplied to a fuel cell dispersed in a plurality of units in a centralized reformer in a collective housing, etc., it is necessary to provide a pipe for leading offgas from the fuel cell to the centralized reformer. It was a waste of equipment. Further, conventionally, there has been a problem that hydrogen contained in off-gas cannot be reused for power generation.

  In order to solve the above-described problems, in the first embodiment of the present invention, a reformer that generates hydrogen, and a fuel cell that generates electric power using the hydrogen generated by the reformer and discharges off-gas containing unused hydrogen. And a hydrogen storage part that stores hydrogen contained in the off-gas when cooled, releases high-purity hydrogen when heated, and supplies it to the fuel cell, and is disposed in the immediate vicinity of the hydrogen storage part and the fuel cell. , A cold water pipe that cools the hydrogen storage part with at least a part of the cooling water supplied to the fuel cell, and hot water that is arranged in the immediate vicinity of the fuel cell and the hydrogen storage part and heats the hydrogen storage part with heat absorbed from the fuel cell A fuel cell system is provided. Therefore, it is possible to effectively use the unused hydrogen contained in the off-gas discharged from the fuel cell, and to make the hydrogen storage unit function using the cooling water and exhaust heat of the fuel cell.

  The hydrogen storage unit is disposed in the immediate vicinity of the cold water pipe, and is disposed in the immediate vicinity of the first hydrogen storage unit cooled by the cold water pipe and storing hydrogen and the hot water pipe, and is heated by the hot water pipe. And a second hydrogen storage unit that releases hydrogen. Thereby, the hydrogen storage part can perform storage and discharge | release of hydrogen simultaneously in parallel.

  By exchanging the first hydrogen storage unit arranged in the immediate vicinity of the cold water pipe and the second hydrogen storage unit arranged in the immediate vicinity of the hot water pipe, each of the first and second hydrogen storage units You may further provide the unit exchange part which switches whether hydrogen is occluded or discharge | releases hydrogen. Thereby, it is possible to switch the hydrogen storage unit between storing and releasing hydrogen with a minimum piping configuration.

  The unit exchange unit replaces the first hydrogen storage unit and the second hydrogen storage unit when the hydrogen release amount per unit time from the second hydrogen storage unit falls below a predetermined standard. Also good. As a result, the switching operation in which hydrogen is stored in the hydrogen storage unit having a reduced hydrogen release amount and hydrogen is released in the other hydrogen storage unit can be executed at an appropriate timing. Therefore, high-purity hydrogen can be stably released and replenished to the fuel cell.

  The unit replacement unit may replace the first hydrogen storage unit and the second hydrogen storage unit when the weight increment of the first hydrogen storage unit reaches a predetermined reference. As a result, the switching operation of causing the hydrogen storage unit whose hydrogen storage amount is approaching the limit to release hydrogen and allowing the other hydrogen storage unit to store hydrogen can be executed at an appropriate timing. Therefore, unused hydrogen contained in the off gas can be stably stored.

  The cold water pipe and the hot water pipe have independent pipes that pass in the immediate vicinity of the two hydrogen storage units, and the fuel cell system further includes an independent pipe that passes in the immediate vicinity of the two hydrogen storage units. A water supply switching unit may be provided that switches between whether the first and second hydrogen storage units store hydrogen or releases hydrogen by switching between cooling water and warm water. Thereby, it is possible to easily switch between hydrogen storage and hydrogen release in each of the hydrogen storage units without moving the hydrogen storage unit.

  When the amount of hydrogen released per unit time from the second hydrogen storage unit falls below a predetermined standard, the water supply switching unit supplies cooling water to the pipe passing through the immediate vicinity of the second hydrogen storage unit. The flow of water in the cold water pipe and the hot water pipe may be switched so that the hot water is supplied to the pipe that is supplied and passes in the immediate vicinity of the first hydrogen storage unit. As a result, the switching operation in which hydrogen is stored in the hydrogen storage unit having a reduced hydrogen release amount and hydrogen is released in the other hydrogen storage unit can be executed at an appropriate timing. Therefore, high-purity hydrogen can be stably released and replenished to the fuel cell.

  The water supply switching unit supplies hot water to a pipe passing through the immediate vicinity of the first hydrogen storage unit when the weight increment of the first hydrogen storage unit reaches a predetermined reference, and the second hydrogen storage unit The flow of water in the cold water pipe and the hot water pipe may be switched so that the cooling water is supplied to the pipe passing through the immediate vicinity of the storage unit. As a result, the switching operation of causing the hydrogen storage unit whose hydrogen storage amount is approaching the limit to release hydrogen and allowing the other hydrogen storage unit to store hydrogen can be executed at an appropriate timing. Therefore, unused hydrogen contained in the off gas can be stably stored.

  When heating the hot water storage tank that is connected to the hot water piping and stores the hot water that has passed through the immediate vicinity of the hydrogen storage section, and the water supplied to the outside from the hot water storage tank, the off gas discharged after the hydrogen storage section absorbs hydrogen You may further provide the hot water heater to burn. As a result, the off-gas discharged from the hydrogen storage unit can be burned in the water heater without leading to the reformer.

  According to a second aspect of the present invention, there is provided a control method for a fuel cell system comprising a reformer, a fuel cell, and a hydrogen storage unit, wherein the reformer generates hydrogen, and the fuel cell includes: Cooling water supplied to the fuel cell by the step of generating off-gas including unused hydrogen generated by the hydrogen generated by the reformer, and the cold water piping arranged in the immediate vicinity of the hydrogen storage unit and the fuel cell A step of cooling at least a portion of the hydrogen storage unit, and a first hydrogen storage unit disposed in the immediate vicinity of the cold water pipe among the plurality of independent hydrogen storage units of the hydrogen storage unit is provided in the cold water pipe. An occlusion step for occlusion of hydrogen contained in the off-gas by being cooled; and a step of heating the hydrogen occlusion unit with heat absorbed by the fuel cell and a hot water pipe arranged in the immediate vicinity of the fuel cell and the hydrogen occlusion unit; A discharge step in which a second hydrogen storage unit disposed in the immediate vicinity of the hot water pipe among the plurality of hydrogen storage units releases the high-purity hydrogen by being heated by the hot water pipe and supplies it to the fuel cell. And switching the first hydrogen storage unit and the second hydrogen storage unit to switch between storing hydrogen and releasing hydrogen in each of the first and second hydrogen storage units. A control method is provided.

  According to a third aspect of the present invention, there is provided a control method for a fuel cell system comprising a reformer, a fuel cell, and a hydrogen storage unit, wherein the reformer generates hydrogen, and the fuel cell includes: Cooling water supplied to the fuel cell by the step of generating off-gas including unused hydrogen generated by the hydrogen generated by the reformer, and the cold water piping arranged in the immediate vicinity of the hydrogen storage unit and the fuel cell A step of cooling at least a portion of the hydrogen storage unit, and a first hydrogen storage unit disposed in the immediate vicinity of the cold water pipe among the plurality of independent hydrogen storage units of the hydrogen storage unit is provided in the cold water pipe. An occlusion step for occlusion of hydrogen contained in the off-gas by being cooled; and a step of heating the hydrogen occlusion unit with heat absorbed by the fuel cell and a hot water pipe arranged in the immediate vicinity of the fuel cell and the hydrogen occlusion unit; A discharge step in which a second hydrogen storage unit disposed in the immediate vicinity of the hot water pipe among the plurality of hydrogen storage units releases the high-purity hydrogen by being heated by the hot water pipe and supplies it to the fuel cell. Then, hot water is supplied to the hot water pipe that passes in the immediate vicinity of the first hydrogen storage unit, and the first hydrogen storage unit is heated to release high-purity hydrogen to the fuel cell. And a step of causing the second hydrogen storage unit to store hydrogen contained in the offgas by supplying cold water to a cold water pipe passing through the immediate vicinity of the second hydrogen storage unit and cooling the second hydrogen storage unit. A control method is provided.

  The above summary of the invention does not enumerate all the necessary features of the present invention, and sub-combinations of these feature groups can also be the invention.

  Hereinafter, the present invention will be described through embodiments of the invention. However, the following embodiments do not limit the invention according to the scope of claims, and all combinations of features described in the embodiments are included. It is not necessarily essential for the solution of the invention.

  The fuel cell system of this embodiment extracts high-purity hydrogen by passing off-gas generated by the fuel cell through a hydrogen storage unit. Then, high-purity hydrogen is released from the hydrogen storage unit and supplied again to the fuel cell. In this case, hydrogen is occluded by cooling the hydrogen occlusion unit using cold water for cooling the fuel cell. Further, the stored hydrogen is released by heating the hydrogen storage unit using the exhaust heat generated from the fuel cell.

  FIG. 1 shows a first embodiment of a fuel cell system 100. The fuel cell system 100 includes a centralized reformer 10, a fuel cell 60, a hydrogen storage unit 70, a cold water pipe 52, and a hot water pipe 54. The central reformer 10 reforms kerosene, city gas, propane gas, and the like to produce hydrogen. The reformed hydrogen supply pipe 12 supplies the hydrogen produced by the centralized reformer 10 to the fuel cell 60. The fuel cell 60 generates power using the hydrogen generated by the centralized reformer 10 and discharges off-gas containing unused hydrogen. The fuel cell 60 is, for example, a polymer electrolyte fuel cell (PEFC). The first off-gas pipe 62 supplies the off-gas discharged from the fuel cell 60 to the hydrogen storage unit 70.

  The hydrogen occlusion unit 70 is, for example, a hydrogen occlusion alloy, occludes hydrogen contained in the off-gas when cooled, releases high-purity hydrogen when heated, and supplies the hydrogen to the fuel cell 60. The hydrogen storage alloy is made of, for example, a Ti—Cr—V alloy. Since the hydrogen storage alloy selectively adsorbs hydrogen, the purity of hydrogen can be increased. The cold water pipe 52 is arranged in the immediate vicinity of the hydrogen storage unit 70 and the fuel cell 60, and cools the hydrogen storage unit 70 with at least a part of the cooling water supplied to the fuel cell 60. The hot water pipe 54 is disposed in the immediate vicinity of the fuel cell 60 and the hydrogen storage unit 70, and heats the hydrogen storage unit 70 with heat absorbed from the fuel cell 60. According to such a configuration, the fuel cell system 100 can effectively use unused hydrogen contained in the offgas discharged from the fuel cell 60. This eliminates the need for piping that guides the off-gas generated by the fuel cell 60 to the centralized reformer 10. In addition, the hydrogen storage unit 70 can be made to function using the cooling water and exhaust heat of the fuel cell 60.

  The hydrogen storage unit 70 includes a plurality of hydrogen storage units 72a and 72b. The hydrogen storage unit 72a is disposed in the immediate vicinity of the cold water pipe 52 and is cooled by the cold water pipe 52 to store hydrogen. The hydrogen storage unit 72b is disposed in the immediate vicinity of the hot water pipe 54 and is heated by the hot water pipe 54 to release hydrogen. Thereby, the hydrogen storage part 70 can perform storage and discharge | release of hydrogen simultaneously in parallel.

  The fuel cell system 100 further includes a unit replacement unit 80. The unit exchanging unit 80 switches between hydrogen storage unit 72a and hydrogen storage unit 72b, thereby switching between hydrogen storage unit 72a and hydrogen storage unit 72b. Thereby, it is possible to switch between hydrogen storage units 72a and 72b storing or releasing hydrogen with a minimum piping configuration. Further, the hydrogen storage unit 70 may include three or more hydrogen storage units. For example, a hydrogen storage unit that stores hydrogen to a full capacity or a hydrogen storage unit that has released most of hydrogen may be provided as a spare hydrogen storage unit.

  The fuel cell system 100 further includes a hot water tank 90, a second offgas pipe 66, and a water heater 92. The hot water tank 90 is connected to the hot water pipe 54 and stores hot water that has passed through the immediate vicinity of the hydrogen storage unit 70. The second off-gas pipe 66 supplies to the water heater 92 off-gas such as carbon monoxide discharged after the hydrogen storage unit 70 stores hydrogen. When heating water supplied from the hot water tank 90 to the outside, the water heater 92 mixes and burns off-gas discharged from the hydrogen storage unit 70 with fuel. As a result, the off-gas discharged from the hydrogen storage unit 70 can be burned by the water heater 92 without being led to the centralized reformer 10. The hot water storage tank 90 is provided with a cold water pipe 56 that discharges the cold water in the lower part and guides it to the cold water pipe 52. Thereby, the hot water of the hot water tank 90 can be efficiently heated.

  When the hydrogen release amount per unit time from the hydrogen storage unit 72b heated by the hot water pipe 54 falls below a predetermined standard, the unit replacement unit 80 is configured to store the hydrogen storage unit 72a and the hydrogen storage unit 72b. Replace. As a result, the switching operation in which hydrogen is stored in the hydrogen storage unit 72b whose hydrogen release amount has decreased and hydrogen is released in the other hydrogen storage unit 72a can be executed at an appropriate timing. Thereby, the hydrogen storage part 70 can discharge | release the high purity hydrogen stably and can replenish the fuel cell 60. FIG.

  The fuel cell system 100 shown in FIG. 1 has occupied portions 50a, 50b, 50c... For each dwelling unit. The occupied portion 50 includes a fuel cell 60, a hydrogen storage unit 70, a unit replacement unit 80, a hot water tank 90, and a water heater 92. However, the form of the fuel cell system 100 is not limited to such a configuration. For example, the fuel cell system 100 may share one hydrogen storage unit 70 among a plurality of dwelling units. Such an example is shown in FIG.

  FIG. 2 shows a second embodiment of the fuel cell system 100. The fuel cell system 100 of the present embodiment is different from the first embodiment shown in FIG. 1 in that a plurality of dwelling units share a set of hydrogen storage units 70. For example, the same configuration as the occupied portion 50a shown in FIG. 1 is installed in one house on each floor of the apartment house, and the fuel cell 60 installed in another dwelling unit on the same floor is connected via the first off-gas pipe 62. The off-gas is recovered in the hydrogen storage unit 70.

  FIG. 3 shows a third embodiment of the fuel cell system 100. Only the configuration different from that of the first embodiment shown in FIG. 1 will be described below. The same components as those in the first embodiment are denoted by the same reference numerals and description thereof is omitted. The fuel cell system 100 of the present embodiment includes independent pipes (52a, 52b, 54a, 54b) that pass through the two hydrogen storage units 72a, 72b in the cold water pipe 52 and the hot water pipe 54, respectively. The fuel cell system 100 of the present embodiment further includes a supply switching unit (82a, 82b, 82c). The supply switching units 82a and 82b switch whether to supply cooling water or hot water to independent pipes (52a, 52b, 54a, 54b) that pass through the two hydrogen storage units 72a, 72b. Accordingly, the supply switching units 82a and 82b switch between the hydrogen storage units 72a and 72b that store hydrogen or release hydrogen.

  The supply switching unit 82c supplies the off-gas discharged from the fuel cell 60 to the hydrogen storage unit 72 that stores hydrogen, that is, the hydrogen storage unit 72 that is supplied with cold water by the supply switching unit 82a. For example, when the supply switching unit 82a supplies cold water to the hydrogen storage unit 72a, the supply switching unit 82c supplies the off gas discharged from the fuel cell 60 to the hydrogen storage unit 72a. In the present embodiment, second off-gas pipes 66a and 66b are provided in the hydrogen storage units 72a and 72b, respectively. The second off-gas pipes 66a and 66b supply the hot water heater 92 with off-gas such as carbon monoxide discharged after the hydrogen storage units 72a and 72b store hydrogen.

  In the present embodiment, high-purity hydrogen pipes 64 a and 64 b are provided in each of the hydrogen storage units 72. The high purity hydrogen pipes 64a and 64b supply the high purity hydrogen released from the hydrogen storage unit 72 to which hot water is supplied by the supply switching unit 82b to the fuel cell 60 again. According to the configuration of this embodiment, the fuel cell system 100 can easily switch between hydrogen storage units 72 and hydrogen storage units 72 without moving the hydrogen storage units 72.

  In addition, the occupied part 50 of a present Example contains structures other than the centralized reformer 10 among the above-mentioned structures. However, the form of the fuel cell system 100 is not limited to such a configuration. For example, the fuel cell system 100 may share one hydrogen storage unit 70 among a plurality of dwelling units. Such an example is shown in FIG.

  FIG. 4 shows a fourth embodiment of the fuel cell system 100. In the present embodiment, the same components as those in the third embodiment are denoted by the same reference numerals, and the description thereof is omitted. The fuel cell system 100 of this embodiment differs from the third embodiment shown in FIG. 3 in that a plurality of dwelling units share a set of hydrogen storage units 70. For example, the same configuration as the occupied portion 50 shown in FIG. 3 is installed in one unit on each floor of the apartment house, and hydrogen is supplied from the fuel cell 60 installed in another dwelling unit on the same floor via the supply switching unit 82c. The off gas is collected in the storage unit 70.

  FIG. 5 shows a fifth embodiment of the fuel cell system 100. In the present embodiment, the same components as those in the first embodiment are denoted by the same reference numerals and description thereof is omitted. The fuel cell system 100 of the present example is different from the first embodiment in that a hydrogen storage unit 70 is provided between the centralized reformer 10 and a plurality of fuel cells 60. The hydrogen storage unit 70 of this embodiment stores the reformed hydrogen produced by the centralized reformer 10 in one hydrogen storage unit 72a, and releases high-purity hydrogen from the other hydrogen storage unit 72b so that each door The fuel cell 60 is supplied. The unit exchanging unit 80 replaces the hydrogen storage unit 72a disposed in the immediate vicinity of the cold water pipe 52 with the hydrogen storage unit 72b disposed in the immediate vicinity of the hot water pipe 54, whereby each of the hydrogen storage units 72a and 72b. Switch between storing hydrogen and releasing hydrogen. The fuel cell system 100 of this embodiment has an advantage that almost no off-gas is generated because high-purity hydrogen is supplied to the fuel cell 60.

  FIG. 6 shows a sixth embodiment of the fuel cell system 100. In the present embodiment, the same components as those in the third embodiment are denoted by the same reference numerals, and the description thereof is omitted. The fuel cell system 100 of the present example differs from the third embodiment in that a hydrogen storage unit 70 is provided between the centralized reformer 10 and a plurality of fuel cells 60. The hydrogen storage unit 70 of this embodiment stores the reformed hydrogen produced by the centralized reformer 10 in one hydrogen storage unit 72a, and releases high-purity hydrogen from the other hydrogen storage unit 72b so that each door The fuel cell 60 is supplied. The supply switching units 82a and 82b switch whether to supply cooling water or hot water to independent pipes (52a, 52b, 54a, 54b) that pass through the two hydrogen storage units 72a, 72b. Accordingly, the supply switching units 82a and 82b switch between the hydrogen storage units 72a and 72b that store hydrogen or release hydrogen. The fuel cell system 100 of this embodiment has an advantage that almost no off-gas is generated because high-purity hydrogen is supplied to the fuel cell 60.

  FIG. 7 is a flowchart showing an operation example of the fuel cell system 100 shown in FIGS. 1 to 4. The control method of the fuel cell system 100 includes a step in which the centralized reformer 10 generates hydrogen (S100), and the fuel cell 60 generates electric power using the hydrogen generated by the centralized reformer 10, and unused hydrogen. A step (S102) of discharging off-gas containing hydrogen, and the hydrogen occlusion unit 70 at least a part of the cooling water supplied to the fuel cell 60 by the cold water pipe 52 disposed in the immediate vicinity of the hydrogen occlusion unit 70 and the fuel cell 60. And the hydrogen storage unit 72 a disposed in the immediate vicinity of the cold water pipe 52 among the plurality of independent hydrogen storage units 72 included in the hydrogen storage unit 70 is cooled to the cold water pipe 52. Thus, an occlusion step (S106) for occlusion of hydrogen contained in the off-gas, and a hot water pipe 54 disposed in the immediate vicinity of the fuel cell 60 and the hydrogen occlusion unit 70 The step of heating the hydrogen storage unit 70 with the heat absorbed from the pond 60 (S108), and the hydrogen storage unit 72b disposed in the immediate vicinity of the hot water pipe 54 among the plurality of hydrogen storage units 72 is connected to the hot water pipe 54. A discharge step (S110) for releasing high-purity hydrogen by heating and supplying it to the fuel cell 60, and a switching step for switching between hydrogen storage or hydrogen release in each of the hydrogen storage units 72a and 72b ( S112).

  FIG. 8 shows details of the switching step (S112) in FIG. The fuel cell system 100 determines whether or not the hydrogen release amount per unit time from the hydrogen storage unit 72b being heated in the hot water pipe 54 is equal to or greater than a predetermined reference value (S200). The reference value in step 200 is a reference value indicating that the amount of hydrogen stored in the hydrogen storage unit 70 is small. For example, the state in which the hydrogen release amount per unit time by the hydrogen storage unit 72 decreases by about 20% from 10% at the peak time is set as the reference value in step 200. When the hydrogen release amount is equal to or greater than the reference value (S200: Yes), it is next determined whether or not the weight increment of the hydrogen storage unit 72a being cooled in the cold water pipe 56 is equal to or less than a predetermined reference value ( S202). The reference value in step 202 is a reference value indicating that the amount of hydrogen stored in the hydrogen storage unit 70 is close to the limit. For example, a weight increment of the hydrogen storage unit 72 in a state where the hydrogen storage unit 72 stores the maximum amount of hydrogen (hereinafter referred to as a maximum weight increment) is previously investigated based on experiments or theoretical calculations. A state in which the weight increment of the hydrogen storage unit 72 during cooling reaches 80% to 90% of the maximum weight increment is set as the reference value in Step 202. When the weight increment is equal to or less than the reference value (S202: Yes), this flow ends. On the other hand, in step 200, when the hydrogen release amount per unit time from the hydrogen storage unit 72b being heated in the hot water pipe 54 is lower than a predetermined reference value (S200: No), or in step 202 When the weight increment of the hydrogen storage unit 72a being cooled by the cold water pipe 56 exceeds a predetermined reference value (S202: No), each of the hydrogen storage units 72a and 72b stores hydrogen or stores hydrogen. Whether to release is switched (S204).

  In the case of the fuel cell system 100 including the unit replacement unit 80 shown in FIGS. 1 and 2, in step 204, the unit replacement unit 80 replaces the hydrogen storage unit 72a and the hydrogen storage unit 72b. On the other hand, in the case of the fuel cell system 100 including the supply switching unit 82 shown in FIGS. 3 and 4, in step 204, the supply switching unit 82 is an independent pipe that passes through the two hydrogen storage units 72 a and 72 b. Switch between cooling water and hot water. As a result, the fuel cell system 100 can easily execute the switching operation of causing the hydrogen storage unit 72 having a reduced hydrogen release amount to store hydrogen and causing the other hydrogen storage unit 72 to release hydrogen. Furthermore, since the switching operation is executed based on the determination result of whether or not the hydrogen release amount per unit time from the hydrogen storage unit 72 during heating is equal to or higher than the reference value, the hydrogen storage unit 70 stores the high purity hydrogen. The fuel cell 60 can be stably discharged. Further, since the switching operation is executed based on the determination result of whether or not the weight increment of the hydrogen storage unit 72 is equal to or less than the reference value, the hydrogen storage unit 70 uses the unused hydrogen contained in the off-gas discharged from the fuel cell 60. Can be stored stably.

  As is clear from the above description, according to the fuel cell system 100 of the present embodiment, a pipe that guides the off-gas discharged from the fuel cell 60 to the centralized reformer 10 is unnecessary. In addition, the fuel excellent in energy saving that effectively uses the unused hydrogen contained in the off-gas discharged from the fuel cell 60 and functions the hydrogen storage unit 70 using the cooling water and exhaust heat of the fuel cell 60. A battery system 100 can be provided.

  As mentioned above, although this invention was demonstrated using embodiment, the technical scope of this invention is not limited to the range as described in the said embodiment. It will be apparent to those skilled in the art that various modifications or improvements can be added to the above-described embodiment. It is apparent from the scope of the claims that the embodiments added with such changes or improvements can be included in the technical scope of the present invention.

1 is a block diagram showing a first embodiment of a fuel cell system 100. FIG. 3 is a block diagram showing a second embodiment of the fuel cell system 100. FIG. 6 is a block diagram showing a third embodiment of the fuel cell system 100. FIG. 6 is a block diagram showing a fourth embodiment of the fuel cell system 100. FIG. 6 is a block diagram showing a fifth embodiment of the fuel cell system 100. FIG. 7 is a block diagram showing a sixth embodiment of the fuel cell system 100. FIG. 4 is a flowchart showing an operation example of the fuel cell system 100. FIG. It is a flowchart which shows the detail of step 112 of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Centralized reformer 12 Reformed hydrogen supply pipe 50 Occupied part 52, 56 Cold water pipe 54 Hot water pipe 60 Fuel cell 62 First off gas pipe 64 High purity hydrogen pipe 66 Second off gas pipe 70 Hydrogen storage part 72 Hydrogen Storage Unit 80 Unit Replacement Unit 82 Supply Switching Unit 90 Hot Water Tank 92 Hot Water Heater 100 Fuel Cell System

Claims (9)

A reformer that produces hydrogen;
A fuel cell that generates electric power from hydrogen generated by the reformer and discharges offgas containing unused hydrogen;
A hydrogen occlusion unit that occludes hydrogen contained in the off-gas by being cooled and releases high-purity hydrogen by being heated to supply the fuel cell;
A cold water pipe that is arranged in the immediate vicinity of the hydrogen storage unit and the fuel cell and cools the hydrogen storage unit with at least a part of cooling water supplied to the fuel cell;
A hot water pipe which is arranged in the immediate vicinity of the fuel cell and the hydrogen storage unit and heats the hydrogen storage unit with heat absorbed from the fuel cell;
A hot water storage tank connected to the hot water piping and storing hot water that has passed through the immediate vicinity of the hydrogen storage unit;
A fuel cell system comprising: a water heater that burns off-gas discharged after the hydrogen storage unit absorbs hydrogen when water supplied to the outside from the hot water tank is heated. The hydrogen storage part is
A first hydrogen storage unit which is arranged in the immediate vicinity of the cold water pipe and is cooled by the cold water pipe and occludes hydrogen;
2. The fuel cell system according to claim 1, further comprising a second hydrogen storage unit that is disposed in the immediate vicinity of the hot water pipe and is heated by the hot water pipe to release hydrogen. By replacing the first hydrogen storage unit disposed in the immediate vicinity of the cold water pipe and the second hydrogen storage unit disposed in the immediate vicinity of the hot water pipe, the first hydrogen storage unit and 3. The fuel cell system according to claim 2, further comprising a unit exchanging unit that switches whether each of the second hydrogen storage units stores hydrogen or releases hydrogen. 4.   The unit exchanging unit is configured such that when the amount of hydrogen released per unit time from the second hydrogen storage unit falls below a predetermined reference, the first hydrogen storage unit and the second hydrogen storage unit The fuel cell system according to claim 3, wherein the fuel cell system is replaced.   The unit replacement unit replaces the first hydrogen storage unit and the second hydrogen storage unit when the weight increment of the first hydrogen storage unit reaches a predetermined reference. 4. The fuel cell system according to 3. The cold water pipe and the hot water pipe have independent pipes that pass through the respective vicinity of the first hydrogen storage unit and the second hydrogen storage unit,
The fuel cell system further includes
The first hydrogen storage unit is switched by switching between supplying cooling water and hot water to the independent pipes that pass through the first hydrogen storage unit and the second hydrogen storage unit. 3. The fuel cell system according to claim 2, further comprising: a water supply switching unit that switches between each of the second hydrogen storage units storing hydrogen or releasing hydrogen.   The water supply switching unit, with respect to the pipe that passes closest to the second hydrogen storage unit, when a hydrogen release amount per unit time from the second hydrogen storage unit falls below a predetermined reference The cooling water is supplied, and the flow of water in the cold water pipe and the hot water pipe is switched so that hot water is supplied to the pipe passing through the immediate vicinity of the first hydrogen storage unit. The fuel cell system described in 1.   The water supply switching unit supplies hot water to the pipe passing through the immediate vicinity of the first hydrogen storage unit when the weight increment of the first hydrogen storage unit reaches a predetermined reference. 7. The fuel cell system according to claim 6, wherein the flow of water in the cold water pipe and the hot water pipe is switched so that the cooling water is supplied to the pipe passing immediately adjacent to the second hydrogen storage unit. . A control method for a fuel cell system comprising a reformer, a fuel cell, and a hydrogen storage unit,
The reformer produces hydrogen;
The fuel cell generates power with hydrogen generated by the reformer and discharges off-gas containing unused hydrogen;
A step of cooling the hydrogen storage unit with at least a part of cooling water supplied to the fuel cell by a cold water pipe arranged in the immediate vicinity of the hydrogen storage unit and the fuel cell;
The hydrogen storage unit stores the hydrogen contained in the off-gas by being cooled by the cold water pipe; and
A hot water pipe arranged in the immediate vicinity of the fuel cell and the hydrogen storage unit, heating the hydrogen storage unit with heat absorbed from the fuel cell;
A discharge step in which the hydrogen storage unit discharges high-purity hydrogen by being heated by the hot water pipe and supplies the hydrogen to the fuel cell;
A hot water tank connected to the hot water pipe stores hot water that has passed through the immediate vicinity of the hydrogen storage unit; and
Wherein the case of heating the water supplied to the outside from the hot water tank, the off-gas the hydrogen storage portion is discharged after absorbing hydrogen, and a step of burning in the water heater, the control method of the fuel cell system.

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