Fuel battery system
The fuel cell system optimizes gas flow rates to maintain efficient power generation during grid outages, reducing surplus power and enhancing energy efficiency without additional power-consuming devices.
Patent Information
- Application Number
- JP2024030358
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2024-02-29
- Publication Date
- 2025-09-10
AI Technical Summary
Existing fuel cell systems face inefficiencies during power outages in grid power supply, leading to the generation of surplus power which is typically consumed by additional devices like heaters, reducing overall energy efficiency.
A fuel cell system that adjusts the flow rates of hydrogen-containing and oxidant gases, as well as a heat medium, using controllers to maintain optimal operation during power outages, thereby reducing surplus power generation.
Enhances energy efficiency by minimizing surplus power generation during grid power outages without the need for additional power-consuming devices, ensuring stable power generation and effective utilization of hydrogen-containing gas.
Smart Images
Figure 2025132652000001_ABST
Abstract
Description
[Technical Field]
[0001] The present disclosure relates to fuel cell systems. [Background technology]
[0002] Patent Document 1 describes a power generation system including a fuel cell device and a control device. The fuel cell device supplies generated power to equipment that generates load fluctuations. The control device controls the generated power of the fuel cell device. When the control device determines that an instantaneous load fluctuation has occurred while performing load following operation, it maintains the generated power of the fuel cell device at a high set generated power and executes output reduction suppression control in which the surplus power is consumed by a surplus power consumption unit. An example of the surplus power consumption unit is a heater that can consume part of the generated power of the fuel cell main body. [Prior art documents] [Patent documents]
[0003] [Patent Document 1] Japanese Patent Application Publication No. 2023-131337 Summary of the Invention [Problem to be solved by the invention]
[0004] The present disclosure provides a fuel cell system that is advantageous from the viewpoint of increasing energy efficiency by reducing the generation of surplus power during a power outage in the grid power supply. [Means for solving the problem]
[0005] The present disclosure provides: a fuel cell stack; a first supply flow path for introducing a hydrogen-containing gas into the fuel cell stack; an anode off-gas flow path that guides an anode off-gas discharged from the fuel cell stack to the first supply flow path; a second supply flow path for introducing an oxidant gas into the fuel cell stack; an exhaust flow path that guides the cathode off-gas discharged from the fuel cell stack to the outside; a first controller; when a power outage occurs in the system power supply and the power generated by the fuel cell stack fluctuates in accordance with an external load, the first controller adjusts the flow rate of the hydrogen-containing gas in the first supply flow path to a first flow rate and adjusts the flow rate of the oxidant gas in the second supply flow path to a second flow rate, regardless of the power generated; A fuel cell system is provided. [Effects of the Invention]
[0006] The technology disclosed herein can provide a fuel cell system that is advantageous from the viewpoint of increasing energy efficiency by reducing the occurrence of surplus power during a power outage in the grid power supply. [Brief explanation of the drawings]
[0007] [Figure 1] FIG. 1 is a diagram showing a schematic configuration of a fuel cell system according to a first embodiment; [Figure 2] A flowchart showing an example of the operation of the fuel cell system shown in FIG. 1. [Figure 3A] Graph showing an example of the change over time in power generation in a fuel cell system when the grid power supply is interrupted [Figure 3B] Graph showing an example of time-dependent changes in the supply flow rate of hydrogen-containing gas and the consumption amount of hydrogen gas when a power outage occurs in the system power supply. [Figure 4] FIG. 10 is a diagram showing a schematic configuration of a fuel cell system according to a second embodiment. DETAILED DESCRIPTION OF THE INVENTION
[0008] (Findings that formed the basis of this disclosure) At the time the inventors conceived the present disclosure, it was common for products to be designed with a heater or the like to consume surplus power, addressing the need to consume surplus power that may be generated during a power grid outage. Under these circumstances, the inventors were inspired by the characteristics of a fuel cell system capable of supplying anode off-gas to a fuel cell stack and came up with the idea of reducing the generation of surplus power during a power grid outage. The inventors then discovered that, in order to realize this idea, it is important to adjust the flow rate of gas supplied to the fuel cell system during a power grid outage, which led to the subject matter of the present disclosure.
[0009] Therefore, the present disclosure provides a fuel cell system that is advantageous from the viewpoint of increasing energy efficiency by reducing the occurrence of surplus power when the grid power supply is out of power.
[0010] Hereinafter, embodiments will be described in detail with reference to the drawings. However, unnecessary detailed description may be omitted. For example, detailed description of already well-known matters or redundant description of substantially the same configuration may be omitted.
[0011] The accompanying drawings and the following description are provided to enable those skilled in the art to fully understand the present disclosure, and are not intended to limit the subject matter recited in the claims.
[0012] (Embodiment 1) Hereinafter, the first embodiment will be described with reference to FIGS. 1 to 3B.
[0013] [1-1.Configuration] FIG. 1 is a diagram schematically illustrating the configuration of a fuel cell system according to a first embodiment. As shown in FIG. 1, the fuel cell system 1a includes a fuel cell stack 10, a first supply flow path 20, an anode off-gas flow path 22, a second supply flow path 30, an exhaust flow path 33, and a first controller 50a. The fuel cell stack 10 includes an anode 11 and a cathode 12. In the fuel cell stack 10, power is generated by an electrochemical reaction between a hydrogen-containing gas and an oxidant gas. The power generated in the fuel cell stack 10 is supplied to an external load (not shown). The fuel cell stack 10 is not limited to a stack of a specific type of fuel cell. The fuel cell stack 10 may be, for example, a stack of a polymer electrolyte fuel cell, a solid oxide fuel cell, a phosphoric acid fuel cell, or a molten carbonate fuel cell.
[0014] The fuel cell system 1a is, for example, connected to a power grid and is able to acquire information relating to power outages in the power grid.
[0015] The first supply flow path 20 is a flow path that introduces the hydrogen-containing gas to the fuel cell stack 10. The first supply flow path 20 is connected, for example, to a supply source (not shown) that stores high-pressure hydrogen-containing gas. The first supply flow path 20 is provided with, for example, a pressure reducing valve 27 and a governor 28. The hydrogen-containing gas supplied from the supply source passes through the pressure reducing valve 27 and the governor 28, thereby adjusting the pressure of the hydrogen-containing gas to a pressure suitable for supply to the anode 11 of the fuel cell stack 10. For example, the first supply flow path 20 is provided with a pressure gauge 29 near the outlet of the governor 28. The pressure gauge 29 measures the pressure of the hydrogen-containing gas that has passed through the governor 28.
[0016] For example, a humidifier (not shown) is provided in the first supply flow path 20. In the humidifier, the hydrogen-containing gas is humidified by water circulating through the fuel cell system 1a.
[0017] The anode off-gas flow path 22 is a flow path that guides the anode off-gas to the first supply flow path 20. The anode off-gas is a gas that is discharged from the anode 11 of the fuel cell stack 10. The anode off-gas may mainly contain unreacted hydrogen gas and water vapor.
[0018] 1, for example, a heat exchanger 24 and a gas-liquid separator 25 are disposed in the anode off-gas flow path 22. The anode off-gas is cooled by passing through the heat exchanger 24, and water vapor contained in the anode off-gas is condensed to produce liquid water.
[0019] The gas-liquid separator 25 separates the liquid water contained in the anode off-gas that has passed through the heat exchanger 24 from the gas containing hydrogen gas. The liquid water separated by the gas-liquid separator 25 is stored, for example, in a tank 62 and is used to cool the fuel cell stack 10, humidify the hydrogen-containing gas, and humidify the oxidant gas.
[0020] The outlet of the anode off-gas flow channel 22 is connected to the first supply flow channel 20. The gas containing hydrogen gas separated in the gas-liquid separator 25 passes through the outlet of the anode off-gas flow channel 22, joins with the flow of hydrogen-containing gas supplied from a supply source, and is supplied toward the anode 11.
[0021] 1, the fuel cell system 1a further includes, for example, a measuring device 26. The measuring device 26 is disposed in the anode offgas flow path 22 and measures the flow rate of hydrogen gas in the anode offgas flow path 22. The measuring device 26 is disposed, for example, downstream of the gas-liquid separator 25 in the anode offgas flow path 22. The measuring device 26 includes, for example, a gas flow meter and a hydrogen gas sensor. In this case, the flow rate of hydrogen gas in the anode offgas flow path 22 is calculated based on the flow rate of the anode offgas measured by the gas flow meter and the hydrogen gas concentration in the anode offgas measured by the hydrogen gas sensor. The flow rate of the hydrogen-containing gas supplied from the supply source is adjusted to a desired range based on the flow rate of hydrogen gas measured by the measuring device 26.
[0022] The second supply flow path 30 is a flow path that introduces the oxidant gas to the fuel cell stack 10. For example, a blower 32 is disposed in the second supply flow path 30. The oxidant gas is, for example, air. For example, a humidifier 35 is disposed in the second supply flow path 30. The oxidant gas is humidified by passing through the humidifier 35 and is then supplied to the fuel cell stack 10.
[0023] The discharge flow path 33 is a flow path that guides the cathode off-gas to the outside of the fuel cell system 1a. The cathode off-gas is gas discharged from the cathode 12 of the fuel cell stack 10. The cathode off-gas may contain unreacted oxidant gas and water vapor. The cathode off-gas may also contain product water, which is water produced by the reaction between hydrogen gas and oxidant gas in the fuel cell stack 10. In the discharge flow path 33, the water vapor contained in the cathode off-gas condenses to produce liquid water. The product water may also exist as liquid water. This liquid water is stored, for example, in a tank 62. A gas-liquid separator may be disposed in the discharge flow path 33, and the liquid water separated in the gas-liquid separator is stored in the tank 62.
[0024] As shown in FIG. 1, the fuel cell system 1a further includes a heat transfer medium flow path 40 and a cooling water flow path 60. The cooling water flow path 60 is a flow path for cooling water for the fuel cell stack 10. Liquid water stored in a tank 62 is used as cooling water for the fuel cell stack 10. A pump 64 is disposed in the cooling water flow path 60, and operation of the pump 64 supplies the cooling water stored in the tank 62 to the fuel cell stack 10. The cooling water passes through the fuel cell stack 10, thereby cooling the fuel cell stack 10 and maintaining the temperature of the fuel cell stack 10 within a desired range.
[0025] The humidifier 35 is disposed, for example, in the cooling water flow path 60, and the cooling water that has passed through the fuel cell stack 10 is supplied to the humidifier 35. As a result, the oxidant gas is humidified in the humidifier 35.
[0026] The fuel cell system 1a includes, for example, a heat exchanger 45, in which heat is exchanged between the coolant in the coolant flow path 60 and the heat medium in the heat medium flow path 40, thereby cooling the coolant. The heat exchanger 45 is supplied with the coolant that has passed through the humidifier 35. The coolant that has passed through the heat exchanger 45 is returned to the tank 62. The heat medium in the heat medium flow path 40 is, for example, water.
[0027] For example, a flow control valve 42 is arranged in the heat medium passage 40. The flow rate of the heat medium in the heat medium passage 40 is adjusted by adjusting the opening degree of the flow control valve 42. For example, a heat exchanger 24 is arranged in the heat medium passage 40. In the heat exchanger 24, heat is exchanged between the anode off-gas and the heat medium. The heat exchanger 24 is arranged, for example, upstream of the heat exchanger 45 in the flow of the heat medium in the heat medium passage 40.
[0028] The first controller 50 a adjusts the flow rate of the hydrogen-containing gas in the first supply passage 20 and the flow rate of the oxidizing gas in the second supply passage 30 .
[0029] The fuel cell system 1a includes, for example, a second controller 50b. The second controller 50b adjusts the flow rate of the heat medium in the heat medium passage 40.
[0030] Each of the first controller 50a and the second controller 50b includes, for example, a microcomputer, a memory, an input / output interface, etc. The memory of the first controller 50a stores a control program for adjusting the flow rate of the hydrogen-containing gas in the first supply passage 20 and the flow rate of the oxidant gas in the second supply passage 30. The memory of the second controller 50b stores a control program for adjusting the flow rate of the heat medium in the heat medium passage 40. The control program is read and executed by the microcomputer. As a result, the first controller 50a controls devices such as pumps, valves, blowers, fans, and governors. The second controller 50b controls devices such as the flow control valve 42.
[0031] [1-2. Operation] The operation of the fuel cell system 1a configured as above will now be described.
[0032] FIG. 2 is a flowchart showing an example of operation of the fuel cell system shown in FIG. 1. As described above, the fuel cell system 1a is connected to a grid power supply. As shown in FIG. 2, in step S101, the fuel cell system 1a acquires information about a power outage of the grid power supply and determines that the grid power supply has experienced a power outage, and then performs the process shown in step S102. In step S102, the first controller 50a adjusts the flow rate of the hydrogen-containing gas in the first supply flow path 20 to a first flow rate F1 and adjusts the flow rate of the oxidant gas in the second supply flow path 30 to a second flow rate F2. In step S102, for example, the flow rate of the hydrogen-containing gas in the first supply flow path 20 downstream of the junction of the first supply flow path 20 and the anode off-gas flow path 22 is adjusted to the first flow rate F1. In addition, the fuel cell stack 10 generates power in accordance with an external load. FIG. 3A is a graph showing an example of the change over time in the power generated in the fuel cell system 1a when the grid power supply is experiencing a power outage. As shown in FIG. 3A, in step S102, the power generated by the fuel cell stack 10 fluctuates in accordance with the external load. For example, when the external load decreases, the AC power of the inverter (not shown) connected to the fuel cell stack 10 decreases, and the DC power also decreases accordingly. As a result, the power generated by the fuel cell stack 10 fluctuates in accordance with the external load.
[0033] The first controller 50a, for example, controls a pump (not shown) for supplying the hydrogen-containing gas to adjust the flow rate of the hydrogen-containing gas in the first supply passage 20 to a first flow rate F1. The first flow rate F1 is not limited to a specific value. For example, the first flow rate F1 is a flow rate of the hydrogen-containing gas corresponding to the rated operation of the fuel cell system 1a. The first flow rate F1 may be a flow rate of the hydrogen-containing gas corresponding to the maximum power generation output of the fuel cell stack 10. The rated output of the fuel cell system 1a and the maximum power generation output of the fuel cell stack 10 may be the same.
[0034] FIG. 3B is a graph showing an example of the time variation of the supply flow rate of the hydrogen-containing gas and the consumption rate of hydrogen gas when the system power supply experiences a power outage. In FIG. 3B, the solid line graph indicates the supply flow rate of the hydrogen-containing gas, and the dashed line graph indicates the consumption rate of hydrogen gas. Because the flow rate of the hydrogen-containing gas in the first supply flow path 20 is adjusted to the first flow rate F1, as shown in FIG. 3B, the supply flow rate of the hydrogen-containing gas to the fuel cell stack 10 is constant at F1. Because the power generated by the fuel cell stack 10 fluctuates in accordance with the external load, the consumption rate of the hydrogen gas in the fuel cell stack 10 also fluctuates in accordance with the external load. An amount of water corresponding to the consumption rate of the hydrogen gas in the fuel cell stack 10 is generated. In this way, the flow rate of the hydrogen-containing gas in the first supply flow path 20 is adjusted to the first flow rate F1 regardless of the power generated by the fuel cell stack 10.
[0035] The first controller 50a controls, for example, the blower 32. As a result, the flow rate of the oxidant gas in the second supply passage 30 is adjusted to a second flow rate F2. The second flow rate F2 is not limited to a specific value. The second flow rate F2 is, for example, a flow rate of the oxidant gas corresponding to the rated operation of the fuel cell system 1a. The second flow rate F2 may be a flow rate of the oxidant gas corresponding to the maximum power generation power of the fuel cell stack 10. The flow rate of the oxidant gas in the second supply passage 30 is adjusted to the second flow rate F2 regardless of the power generation power of the fuel cell stack 10.
[0036] In step S102, the cooling water stored in the tank 62 continues to return to the tank 62 through the cooling water passage 60, passing through the fuel cell stack 10, the humidifier 35, and the heat exchanger 45. In other words, the cooling water circulates through the fuel cell stack 10, the humidifier 35, and the heat exchanger 45 through the cooling water passage 60. In step S102, the heat medium for cooling the cooling water of the fuel cell stack 10 continues to be supplied to the outside of the fuel cell system 1a through the heat exchanger 24, the heat exchanger 45, and the flow control valve 42 in the heat medium passage 40.
[0037] 2, in step S103, it is determined whether the power outage in the system power supply has been resolved. If the result of this determination is affirmative, the adjustment of the flow rate of the hydrogen-containing gas in the first supply flow path 20 and the flow rate of the oxidant gas in the second supply flow path 30 transitions to the normal mode, and the series of processes ends. For example, the flow rate of the hydrogen-containing gas in the first supply flow path 20 and the flow rate of the oxidant gas in the second supply flow path 30 are adjusted to vary in accordance with the external load. In this case, the power generation efficiency in the normal mode is likely to be high, and the manufacturing cost of the fuel cell system 1a is likely to be low.
[0038] If the result of the determination in step S103 is negative, then in step S105, it is determined whether the period DL during which the power generation power of the fuel cell stack 10 is equal to or less than a predetermined value is equal to or greater than a predetermined period V1. In this case, the predetermined value of the power generation power is not limited to a specific value. The predetermined value of the power generation power is, for example, 60% of the maximum power generation power of the fuel cell stack 10. In step S105, the second controller 50b acquires time-varying data on the power generation power of the fuel cell stack 10 measured by, for example, a wattmeter (not shown). Based on the time-varying data on the power generation power of the fuel cell stack 10, the second controller 50b determines whether the period DL is equal to or greater than the predetermined period V1. If the result of the determination in step S105 is positive, then the process proceeds to step S106, where the second controller 50b increases the flow rate of the heat medium in the heat medium passage 40 while continuing the process of step S102. For example, the second controller 50b controls the flow rate control valve 42 so that the opening degree of the flow rate control valve 42 increases, thereby increasing the flow rate of the heat medium in the heat medium passage 40.
[0039] For example, if the power generation capacity of the fuel cell stack 10 remains low and the period DL is equal to or greater than the predetermined period V1, the amount of water produced in the fuel cell stack 10 decreases. In addition, because the flow rate of the oxidant gas in the second supply passage 30 is adjusted to the second flow rate F2 regardless of the power generation capacity of the fuel cell stack 10, the amount of water vapor contained in the oxidant gas humidified by the humidifier 35 tends to increase. Therefore, the amount of water vapor contained in the cathode off-gas discharged to the outside of the fuel cell system 1a tends to remain high. If this condition continues, the amount of water vapor discharged to the outside of the fuel cell system 1a may continue to exceed the amount of water produced in the fuel cell stack 10, and the amount of cooling water stored in the tank 62 may decrease. In this case, it is expected that the fuel cell stack 10 may not be sufficiently cooled, making it difficult to continue generating power. On the other hand, if the flow rate of the heat medium in the heat medium passage 40 is increased when it is determined that the period DL is equal to or greater than the predetermined period V1, the temperature of the cooling water in the cooling water passage 60 may decrease. This reduces the amount of water used to humidify the oxidant gas in the humidifier 35, making it difficult for the amount of cooling water stored in the tank 62 to decrease, and allowing a sufficient amount of cooling water to be stored in the tank 62.
[0040] If the determination result in step S105 is negative, the flow rate of the heat medium in the heat medium passage 40 is not changed, and the process of step S102 is continued.
[0041] (Embodiment 2) The second embodiment will be described below with reference to FIG.
[0042] [2-1.Configuration] 4 is a diagram schematically illustrating the configuration of a fuel cell system 1b according to embodiment 2. Except for the parts that will be particularly described, the fuel cell system 1b has the same configuration as the fuel cell system 1a. The above description of the fuel cell system 1a also applies to the fuel cell system 1b, unless technically inconsistent.
[0043] The fuel cell system 1b includes a plurality of fuel cell stacks 10. The plurality of fuel cell stacks 10 are, for example, electrically connected in series. The first supply flow path 20 is configured to guide a hydrogen-containing gas to the plurality of fuel cell stacks 10. The anode off-gas flow path 22 is configured to join anode off-gases discharged from the plurality of fuel cell stacks 10 and guide the joined gas to the first supply flow path 20. The second supply flow path 30 is configured to guide an oxidant gas to the plurality of fuel cell stacks 10. The discharge flow path 33 is configured to guide cathode off-gases discharged from the plurality of fuel cell stacks 10 to the outside.
[0044] [2-2. Operation] In the fuel cell system 1b, when it is determined that the grid power supply has experienced a power outage, the first controller 50a adjusts the flow rate of the hydrogen-containing gas in the first supply flow path 20 and the flow rate of the oxidant gas in the second supply flow path 30, similar to step S102 in FIG. 2 . As a result, the flow rate of the hydrogen-containing gas in the first supply flow path 20 is adjusted to a first flow rate F1, and the flow rate of the oxidant gas in the second supply flow path 30 is adjusted to a second flow rate F2. In addition, the multiple fuel cell stacks 10 generate power in accordance with an external load. In this case, the first flow rate F1 may be a flow rate of the hydrogen-containing gas corresponding to the rated operation of the fuel cell system 1a, or may be a flow rate of the hydrogen-containing gas corresponding to the maximum power generation power of the multiple fuel cell stacks 10. The second flow rate F2 may be a flow rate of the oxidant gas corresponding to the rated operation of the fuel cell system 1a, or may be a flow rate of the oxidant gas corresponding to the maximum power generation power of the multiple fuel cell stacks 10. The rated output of the fuel cell system 1a and the maximum power generation output of the multiple fuel cell stacks 10 may be the same.
[0045] (Other embodiments) As described above, Embodiments 1 and 2 have been described as examples of the technology disclosed in the present application. However, the technology in the present disclosure is not limited to these and can be applied to embodiments in which modifications, substitutions, additions, omissions, etc. are made. Furthermore, it is also possible to combine the components described in Embodiments 1 and 2 above to create new embodiments.
[0046] Therefore, other embodiments will be exemplified below.
[0047] The heat medium passage 40 may be provided with a heat exchanger other than the heat exchanger 24 and the heat exchanger 45. For example, the heat medium passage 40 may be provided with a heat exchanger for exchanging heat between the cathode off-gas in the discharge passage 33 and the heat medium.
[0048] The anode off-gas flow path may be connected to a flow path for purging the gas separated in the gas-liquid separator 25, and a purge valve may be disposed in the flow path. In this case, the purged gas may be mixed with the cathode off-gas and discharged to the outside of the fuel cell system 1a or 1b.
[0049] In each embodiment, each flow path may be formed by at least one pipe, and each flow path may be provided with necessary devices such as valves and sensors.
[0050] (Addendum) The above description of the embodiments discloses the following techniques.
[0051] (Technology 1) a fuel cell stack; a first supply flow path for introducing a hydrogen-containing gas into the fuel cell stack; an anode off-gas flow path that guides an anode off-gas discharged from the fuel cell stack to the first supply flow path; a second supply flow path for introducing an oxidant gas into the fuel cell stack; an exhaust flow path that guides the cathode off-gas discharged from the fuel cell stack to the outside; a first controller; when a power outage occurs in the system power supply and the power generated by the fuel cell stack fluctuates in accordance with an external load, the first controller adjusts the flow rate of the hydrogen-containing gas in the first supply flow path to a first flow rate and adjusts the flow rate of the oxidant gas in the second supply flow path to a second flow rate, regardless of the power generated; Fuel cell system.
[0052] According to Technology 1, when the grid power supply fails, the power generated by the fuel cell stack fluctuates in accordance with the external load, making it less likely that surplus power will be generated. Regardless of the power generated, the flow rate of the hydrogen-containing gas in the first supply flow path is adjusted to a first flow rate, and the flow rate of the oxidant gas in the second supply flow path is adjusted to a second flow rate, making it easier for the fuel cell system to respond to fluctuations in the external load. The anode off-gas is guided to the first supply flow path through the anode off-gas flow path, making effective use of the hydrogen-containing gas, which tends to increase the energy efficiency of the fuel cell system. No heater or other device is required to consume surplus power.
[0053] (Technology 2) the first flow rate is a flow rate of the hydrogen-containing gas corresponding to a rated operation of the fuel cell system, the second flow rate is a flow rate of the oxidant gas corresponding to the rated operation. 10. The fuel cell system according to claim 1.
[0054] According to Technique 2, even if the external load fluctuates when the grid power supply is interrupted, the fuel cell stack can generate power within the range of power generation corresponding to the rated operation of the fuel cell system.
[0055] (Technology 3) the first flow rate is a flow rate of the hydrogen-containing gas corresponding to a maximum power generation output of the fuel cell stack, the second flow rate is a flow rate of the oxidant gas corresponding to the maximum power generation power. 10. The fuel cell system according to claim 1.
[0056] According to Technique 3, even if the external load fluctuates when the grid power supply is interrupted, the fuel cell stack can generate power within the range of power generation corresponding to the maximum power generation.
[0057] (Technology 4) The anode off-gas passage further includes a measuring device disposed in the anode off-gas passage and measuring a flow rate of hydrogen gas in the anode off-gas passage. 4. A fuel cell system according to any one of claims 1 to 3.
[0058] According to the fourth technique, when the power grid power fails, the flow rate of the hydrogen-containing gas in the first supply channel can be adjusted to the first flow rate based on the measured value of the flow rate of the hydrogen gas in the anode off-gas channel.
[0059] (Technology 5) a heat medium flow path that is a flow path of a heat medium involved in cooling the fuel cell stack; a second controller that adjusts the flow rate of the heat medium in the heat medium flow path, the second controller increases the flow rate of the heat medium in the heat medium flow path when the power grid power supply is powered out and the power generated by the fuel cell stack fluctuates in accordance with the external load, and the power generated remains equal to or lower than a predetermined value for a predetermined period of time or more. 5. A fuel cell system according to any one of claims 1 to 4.
[0060] According to Technique 5, for example, when a heat medium cools the cooling water of a fuel cell stack, the cooling water of the fuel cell stack is unlikely to run short even if the system power supply fails and the power generation of the fuel cell stack remains low.
[0061] (Technology 6) a plurality of fuel cell stacks; a first supply flow path for introducing a hydrogen-containing gas into the plurality of fuel cell stacks; an anode off-gas flow path that joins anode off-gas discharged from the plurality of fuel cell stacks and guides the anode off-gas to the first supply flow path; a second supply flow path for introducing an oxidant gas to the plurality of fuel cell stacks; an exhaust flow path that guides cathode off-gas discharged from the plurality of fuel cell stacks to the outside; a first controller; when a power outage occurs in the system power supply and the power generated by the plurality of fuel cell stacks fluctuates in accordance with an external load, the first controller adjusts the flow rate of the hydrogen-containing gas in the first supply flow path to a first flow rate and adjusts the flow rate of the oxidant gas in the second supply flow path to a second flow rate regardless of the power generated; Fuel cell system.
[0062] According to Technology 6, when the grid power supply experiences a power outage, the generated power of the multiple fuel cell stacks fluctuates in accordance with the external load, making it less likely that surplus power will be generated. Additionally, the flow rate of the hydrogen-containing gas in the first supply flow path is adjusted to a first flow rate, and the flow rate of the oxidant gas in the second supply flow path is adjusted to a second flow rate, regardless of the generated power, making it easier for the fuel cell system to respond to fluctuations in the external load. Because the anode off-gas is guided to the first supply flow path through the anode off-gas flow path, the hydrogen-containing gas is effectively utilized, making it easier to increase the energy efficiency of the fuel cell system. A heater or the like is not required to consume surplus power. Additionally, because the anode off-gas discharged from the multiple fuel cell stacks is joined and guided to the first supply flow path, the flow rate of the hydrogen-containing gas supplied to the multiple fuel cell stacks is less likely to vary. [Industrial Applicability]
[0063] The techniques of the present disclosure are useful in fuel cell systems. [Explanation of symbols]
[0064] 1a, 1b Fuel cell system 10. Fuel Cell Stack 20 First supply channel 22 Anode off-gas flow path 26 Measuring instruments 30 Second supply channel 33 Discharge flow path 40 Heat transfer medium flow path 50a First Controller 50b Second controller
Claims
1. a fuel cell stack; a first supply flow path for introducing a hydrogen-containing gas into the fuel cell stack; an anode off-gas flow path that guides an anode off-gas discharged from the fuel cell stack to the first supply flow path; a second supply flow path for introducing an oxidant gas into the fuel cell stack; an exhaust flow path that guides the cathode off-gas discharged from the fuel cell stack to the outside; a first controller; when a power outage occurs in the system power supply and the power generated by the fuel cell stack fluctuates in accordance with an external load, the first controller adjusts the flow rate of the hydrogen-containing gas in the first supply flow path to a first flow rate and adjusts the flow rate of the oxidant gas in the second supply flow path to a second flow rate, regardless of the power generated; Fuel cell system.
2. the first flow rate is a flow rate of the hydrogen-containing gas corresponding to a rated operation of the fuel cell system, the second flow rate is a flow rate of the oxidant gas corresponding to the rated operation. The fuel cell system according to claim 1 .
3. the first flow rate is a flow rate of the hydrogen-containing gas corresponding to a maximum power generation output of the fuel cell stack, the second flow rate is a flow rate of the oxidant gas corresponding to the maximum power generation power. The fuel cell system according to claim 1 .
4. The anode off-gas passage further includes a measuring device disposed in the anode off-gas passage and measuring a flow rate of hydrogen gas in the anode off-gas passage. The fuel cell system according to claim 1 .
5. a heat medium flow path that is a flow path of a heat medium involved in cooling the fuel cell stack; a second controller that adjusts the flow rate of the heat medium in the heat medium flow path, the second controller increases the flow rate of the heat medium in the heat medium flow path when the power grid power supply is powered out and the power generated by the fuel cell stack fluctuates in accordance with the external load, and the power generated remains equal to or lower than a predetermined value for a predetermined period of time or more. The fuel cell system according to claim 1 .
6. a plurality of fuel cell stacks; a first supply flow path for introducing a hydrogen-containing gas into the plurality of fuel cell stacks; an anode off-gas flow path that joins anode off-gas discharged from the plurality of fuel cell stacks and guides the anode off-gas to the first supply flow path; a second supply flow path for introducing an oxidant gas to the plurality of fuel cell stacks; an exhaust flow path that guides cathode off-gas discharged from the plurality of fuel cell stacks to the outside; a first controller; when a power outage occurs in the system power supply and the power generated by the plurality of fuel cell stacks fluctuates in accordance with an external load, the first controller adjusts the flow rate of the hydrogen-containing gas in the first supply flow path to a first flow rate and adjusts the flow rate of the oxidant gas in the second supply flow path to a second flow rate regardless of the power generated; Fuel cell system.
Citation Information
Patent Citations
Power generation system
JP2023131337A