Fuel cell system

Abstract

This invention provides a technology suitable for a fuel cell system comprising multiple fuel cell units, which allows for maintaining the fuel cell units within an appropriate temperature range while simultaneously recovering the cooling medium used to cool the fuel cell units within a desired temperature range. [Solution] The fuel cell system 100 of this disclosure comprises a plurality of fuel cell units 10, a cooling device 20 for cooling the plurality of fuel cell units 10, and a control device 30 for controlling the cooling device 20. The cooling device 20 includes a cooling channel 21 for supplying and recovering a cooling medium in parallel to the plurality of fuel cell units 10, and a pump 22. The cooling channel 21 includes a bypass path 23 for returning the cooling medium, which is discharged from the pump 22 and supplied to the fuel cell units 10, to the upstream side of the pump 22's intake. The control device 30 controls the flow rate of the cooling medium by the pump 22 and the bypass path 23 based on the operating data of the fuel cell system 100.

Description

Technical Field

[0001] The present disclosure relates to a fuel cell system.

Background Art

[0002] Patent Document 1 discloses a cooling control device for a fuel cell that can control the flow rate of a coolant according to the output characteristics of the fuel cell.

[0003] Also, as a configuration for obtaining a high power generation amount, a fuel cell system including a plurality of fuel cells has been proposed. Patent Document 2 discloses a technique for efficiently using waste heat generated by a plurality of fuel cells in a fuel cell system including a plurality of fuel cells with a simple configuration.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] Since the cooling control device described in Patent Document 1 adjusts the flow rate of the coolant according to the output characteristics of the fuel cell, it can mitigate the temperature rise of the fuel cell due to an increase in the heat generation amount and stably cool the fuel cell. However, the cooling control device described in Patent Document 1 is not for controlling the temperature of each of a plurality of fuel cells within an appropriate range in a fuel cell system including a plurality of fuel cells. Therefore, it is difficult to appropriately control the temperature of each fuel cell in a fuel cell system including a plurality of fuel cells by the cooling control device described in Patent Document 1.

[0006] According to the technology described in Patent Document 2, in a fuel cell system comprising multiple fuel cells, excess heat generated by the multiple fuel cells can be dissipated.

[0007] However, in a fuel cell system comprising multiple fuel cells, in order to maintain the temperature of each fuel cell within a temperature range suitable for operation, and to efficiently utilize the waste heat by recovering the cooling medium used to cool the fuel cells within a desired temperature range, a wide range of control over the flow rate of the cooling medium is required. Therefore, the technology described in Patent Document 2 has room for improvement in terms of wide range of control over the flow rate of the cooling medium in a fuel cell system comprising multiple fuel cells.

[0008] This disclosure provides a technology suitable for a fuel cell system comprising multiple fuel cells, which maintains the temperature of each fuel cell within a temperature range appropriate for operation, while simultaneously recovering the cooling medium used to cool the fuel cells within a desired temperature range. [Means for solving the problem]

[0009] The first aspect of this disclosure is: Multiple fuel cell units, A cooling device for cooling the aforementioned multiple fuel cell units, A control device for controlling the cooling device, A fuel cell system equipped with, The cooling device, A cooling channel for supplying and recovering a cooling medium in parallel to the plurality of fuel cell units, A pump provided on the cooling channel and for adjusting the flow rate of the cooling medium, Includes, The cooling channel includes a bypass path that bypasses the pump for returning the cooling medium, which is discharged from the pump and supplied to the plurality of fuel cell units, to the upstream side of the pump's suction port. The control device controls the flow rate of the cooling medium in the cooling channel by the pump and the bypass path based on the operating data of the fuel cell system in order to keep the temperatures of the plurality of fuel cell units within a predetermined range. We provide fuel cell systems.

[0010] A second aspect of this disclosure is: Multiple fuel cell units, A cooling device for cooling the aforementioned multiple fuel cell units, A control device for controlling the cooling device, Equipped with, The cooling device, A cooling channel for supplying and recovering a cooling medium in parallel to the plurality of fuel cell units, A variable flow pump provided on the cooling channel and for adjusting the flow rate of the cooling medium, Includes, The control device controls the discharge amount of the variable flow pump based on the operating data of the plurality of fuel cell units in order to keep the temperatures of the plurality of fuel cell units within a predetermined range. We provide fuel cell systems. [Effects of the Invention]

[0011] The technology described herein is suitable for a fuel cell system comprising multiple fuel cells, in which the temperature of each fuel cell is maintained within a temperature range appropriate for operation, and the cooling medium used to cool the fuel cells is recovered within a desired temperature range. [Brief explanation of the drawing]

[0012] [Figure 1] Configuration diagram of the fuel cell system according to Embodiment 1 [Figure 2] Configuration diagram of the fuel cell system according to Embodiment 2 [Figure 3] Configuration diagram showing a first modified example of the fuel cell system according to Embodiment 1. [Figure 4] Configuration diagram showing a second modified example of the fuel cell system according to Embodiment 1. [Figure 5] Configuration diagram showing the third modification of the fuel cell system according to Embodiment 1 [Figure 6] Configuration diagram showing the fourth modification of the fuel cell system according to Embodiment 1 [Figure 7] Configuration diagram showing the fifth modification of the fuel cell system according to Embodiment 1 [Figure 8] Configuration diagram showing the sixth modification of the fuel cell system according to Embodiment 1 [Figure 9] Configuration diagram showing the seventh modification of the fuel cell system according to Embodiment 1 [Figure 10] Configuration diagram showing the eighth modification of the fuel cell system according to Embodiment 1

Modes for Carrying Out the Invention

[0013] (Findings etc. that are the basis of the present disclosure) As described in the above [Background Art] section, as a configuration for obtaining a high power generation amount, a fuel cell system including a plurality of fuel cells has been proposed. In such a fuel cell system, the power generation capacity of the entire system can be designed within a desired range by controlling the number of fuel cells to be provided, and the output can also be controlled as needed by controlling the number of operating fuel cells and load fluctuations of each fuel cell.

[0014] In the fuel cell system as described above, it is also possible to provide a cooling function for each fuel cell and exhaust waste heat for each fuel cell. However, when a cooling function is provided for each fuel cell, there is a problem that the configuration of each fuel cell becomes complicated and the installation space also increases. Therefore, for example, as described in Patent Document 2, a cooling device capable of cooling a plurality of fuel cells is used.

[0015] On the other hand, in order to generate electricity efficiently while suppressing the degradation of fuel cells, it is necessary to maintain the fuel cells within an appropriate temperature range. Since the heat output of a fuel cell changes depending on the amount of electricity generated, when multiple fuel cells are installed and their operating conditions (i.e., the amount of electricity generated) differ, maintaining each fuel cell within an appropriate temperature range becomes extremely complex in terms of cooling control, particularly the flow rate control of the cooling medium. Furthermore, since the temperature of the cooling medium, such as cooling water, can also change depending on the climate and other environmental factors, the flow rate control of the cooling medium becomes even more complex when its temperature is taken into consideration.

[0016] Furthermore, in order to effectively utilize the waste heat from fuel cells, it is also necessary to recover the cooling medium used to cool the fuel cells within a desired temperature range.

[0017] In light of these circumstances, the inventors have conducted further studies and have discovered a new technology that enables control over a wide range of the flow rate of the cooling medium in order to achieve the complex cooling control of fuel cells described above, that is, to maintain the temperature of each fuel cell within a temperature range appropriate for operation, and to recover the cooling medium used to cool the fuel cells within a desired temperature range.

[0018] Furthermore, the term "fuel cell" as used above refers to a "fuel cell unit" which includes a fuel cell stack and auxiliary equipment for operating the fuel cell stack.

[0019] The embodiments will be described in detail below with reference to the drawings. However, unnecessary details may be omitted. For example, detailed explanations of already well-known matters or redundant explanations of substantially identical configurations may be omitted. This is to avoid the following explanation becoming unnecessarily verbose and to facilitate understanding for those skilled in the art.

[0020] The accompanying drawings and the following description are provided to enable those skilled in the art to fully understand this disclosure and are not intended to limit the subject matter described in the claims.

[0021] (Embodiment 1) The embodiments will be described below with reference to Figure 1.

[0022] [1-1. Structure] Figure 1 is a diagram illustrating the configuration of a fuel cell system according to Embodiment 1. As shown in Figure 1, the fuel cell system 100 according to Embodiment 1 comprises a plurality of fuel cell units 10, a cooling channel 21, a pump 22, and a control device 30. The cooling device 20 for cooling the plurality of fuel cell units 10 is composed of the cooling channel 21 and the pump 22. The cooling channel 21 is a channel for supplying and recovering a cooling medium to the plurality of fuel cell units 10 in parallel. The pump 22 is provided on the cooling channel 21 and adjusts the flow rate of the cooling medium. The control device 30 controls the cooling device 20.

[0023] In Embodiment 1, the fuel cell system 100 further includes a storage tank 40. The storage tank 40 stores a cooling medium. The cooling medium is, for example, water or antifreeze. Here, we will describe an example in which water is used as the cooling medium for cooling the fuel cell unit 10.

[0024] The fuel cell system 100 may further include a pressure gauge 50 provided on the cooling channel 21 for measuring the discharge pressure of the cooling water in the pump 22.

[0025] Each of the multiple fuel cell units 10 includes a fuel cell stack 11 and auxiliary equipment (not shown) necessary to operate the fuel cell stack 11. Figure 1 shows the first fuel cell unit 101, the second fuel cell unit 102, ... the nth fuel cell unit 10. n An example is shown in which n fuel cell units 10 (where n is an integer greater than or equal to 3) are connected to each other.

[0026] Examples of fuel cells include polymer electrolyte membrane fuel cells, solid oxide fuel cells, phosphoric acid fuel cells, and molten carbonate fuel cells. Fuel gas and oxidizer gas are supplied to the fuel cell stack 11, and electricity is generated by the reaction of the fuel gas and oxidizer gas in the fuel cell stack 11. The fuel supplied to the fuel cell stack 11 is, for example, pure hydrogen. In this case, the fuel cell system 100 further includes a tank (not shown) in which pure hydrogen is stored. Hydrogen gas as fuel gas is supplied from this tank to the fuel cell stack 11. The fuel used in the fuel cell system 100 may also include hydrocarbon gases such as methane gas, propane gas, and butane gas. In this case, the fuel cell system 100 includes a reformer. Hydrogen-containing gas as fuel gas is produced from hydrocarbon gas in the reformer, and the hydrogen-containing gas is supplied to the fuel cell stack 11. Examples of fuels containing hydrocarbon gases are city gas and LPG.

[0027] The fuel cell unit 10 is connected to a load and supplies the generated power to the load. The load is installed in places such as factories, hospitals, schools, and commercial facilities.

[0028] Each of the multiple fuel cell units 10 is equipped with, for example, a throttle valve 12 that adjusts the flow rate of cooling water supplied to the fuel cell unit 10.

[0029] The fuel cell unit 10 may be a fuel cell operating at rated load, or it may be a fuel cell capable of partial load operation. If the fuel cell unit 10 is a fuel cell capable of partial load operation, it is necessary to control the flow rate of the cooling water over a wider range. Therefore, the fuel cell system 100 according to Embodiment 1 may be more effective when the fuel cell unit 10 is a fuel cell capable of partial load operation.

[0030] As described above, the cooling channel 21 is a channel for supplying and recovering cooling water to multiple fuel cell units 10 in parallel. The cooling channel 21 includes a bypass path 23 that bypasses the pump 22 to return the cooling water, which is discharged from the pump 22 and supplied to the multiple fuel cell units 10, to the upstream side of the pump 22's intake. The bypass path 23 is provided with, for example, a throttle valve 24 to adjust the flow rate of the cooling water on the bypass path 23.

[0031] As described above, the pump 22 is installed on the cooling channel 21 and adjusts the flow rate of the cooling water. As shown in Figure 1, there may be multiple pumps 22, in which case the multiple pumps 22 are connected in parallel to each other.

[0032] Pump 22 may be a constant flow pump or a variable flow pump. As will be described later, according to the fuel cell system 100 of Embodiment 1, a wide range of cooling water control is possible regardless of the type of pump used. Therefore, even when an inexpensive constant flow pump is used, the flow rate of the cooling water can be controlled over a wide range. When a variable flow pump is used, the flow rate of the cooling water can be controlled over an even wider range and with greater precision.

[0033] As described above, the control device 30 controls the cooling device 20. Based on the operating data of the fuel cell system 100, the control device 30 controls the flow rate of cooling water in the cooling channel 21 by pump 22 and bypass path 23 in order to keep the temperatures of the multiple fuel cell units 10 within a predetermined range. For example, the control device 30 controls pump 22 and throttle valve 24 on bypass path 23.

[0034] The control device 30 may further control the operation of multiple fuel cell units 10. For example, the control device 30 may control the throttle valve 12 that adjusts the flow rate of cooling water supplied to the fuel cell unit 10 according to the amount of power generated by the fuel cell unit 10, or according to whether the fuel cell unit 10 is in the initial stage of operation or not.

[0035] The operating data of the fuel cell system 100 mentioned above includes, for example, the discharge pressure of the cooling water in the pump 22, the opening degree of the throttle valve 12 provided in each of the multiple fuel cell units 10, and the amount of power generated by each of the multiple fuel cell units 10.

[0036] The control device 30 may, for example, control the opening degree of the throttle valve 24 provided in the bypass path 23 based on at least one selected from the group consisting of the discharge pressure of the cooling water in the pump 22, the opening degree of the throttle valve 12 provided in each of the multiple fuel cell units 10, and the amount of power generated by each of the multiple fuel cell units 10.

[0037] Furthermore, if multiple pumps 22 are provided, the control device 30 may, for example, control the number of operating pumps 22 based on at least one selected from the group consisting of the discharge pressure of the cooling water in the pumps 22, the opening degree of the throttle valves 12 provided in each of the multiple fuel cell units 10, and the power generation amount of each of the multiple fuel cell units 10. In this case, the control device 30 may also further control the opening degree of the throttle valve 24 provided in the bypass path 23 based on at least one selected from the group consisting of the discharge pressure of the cooling water in the pumps 22, the opening degree of the throttle valves 12 provided in each of the multiple fuel cell units 10, and the power generation amount of each of the multiple fuel cell units 10.

[0038] The control device 30 is, for example, a computer equipped with a memory device that stores a program necessary for operating the fuel cell system 100, and a processor that reads the program from the memory device and executes it.

[0039] Cooling water in the storage tank 40 is supplied from the storage tank 40 to the cooling channel and then supplied in parallel to the multiple fuel cell units 10 via the pump 22. The cooling water's temperature rises due to the heat generated in each fuel cell unit 10 and it returns to the storage tank 40. The heated cooling water in the storage tank 40 may be used, for example, as hot water for hot water supply. The temperature of the cooling water in the storage tank 40 may be adjusted, for example, by introducing tap water.

[0040] [1-2. Operation] An example of the operation of the fuel cell system 100 will be described.

[0041] The control device 30 controls the flow rate of cooling water in the cooling channel 21 by pump 22 and bypass path 23 based on operating data of the fuel cell system 100 in order to keep the temperatures of the multiple fuel cell units 10 within a predetermined range.

[0042] Specifically, the flow rate of cooling water in the cooling passage 21 is controlled to an appropriate range by controlling the pump 22 and the bypass path 23 based on, for example, at least one selected from the group consisting of the discharge pressure of the cooling water in the pump 22, the opening degree of the throttle valve 12 provided in each of the multiple fuel cell units 10, and the power generation amount of each of the multiple fuel cell units 10. Control of the pump 22 refers to, for example, the number of pumps operating if the pump 22 is a constant flow pump, or the number of pumps operating and the discharge amount of each pump 22 if the pump 22 is a variable flow pump. Control of the bypass path 23 refers to, for example, the opening and closing of the throttle valve 24 on the bypass path 23. By increasing the number of pumps operating, increasing the discharge amount of the pumps 22 if they are variable flow pumps, or lowering the opening degree of the throttle valve 24 on the bypass path 23, the flow rate of cooling water in the cooling passage 21 can be increased to a desired value. By reducing the number of operating pumps 22, reducing the discharge rate of pumps 22 if they are variable flow pumps, or increasing the opening degree of the throttle valve 24 on the bypass path 23, the flow rate of cooling water in the cooling passage 21 can be reduced to a desired value.

[0043] As described above, in the fuel cell system 100 according to Embodiment 1, by combining the control of the pump 22 and the control of the bypass path 23, the flow rate of the cooling water can be controlled to a desired value according to the operating conditions of the fuel cell system 100.

[0044] Furthermore, the control device 30 can obtain information on the discharge pressure of the cooling water in the pump 22 from the pressure gauge 50. In addition, the control device 30 can obtain information on the opening degree of the throttle valve 12 of the fuel cell unit 10, and information on the amount of power generated by each fuel cell unit 10, from each fuel cell unit 10.

[0045] For example, let's assume that fuel cell system 100 is a fuel cell system operated under the following conditions. • Hot water temperature from the fuel cell unit during fuel cell system operation: 50°C to 60°C • Inlet water temperature to the fuel cell unit during fuel cell system operation: 5°C to 45°C • Heat output per fuel cell unit: 8485W / unit at rated operation, 12000W / unit at maximum operation

[0046] In a fuel cell system under the above conditions, the cooling water flow rate is lowest at 2.7 L / min when supplying cooling water to a fuel cell unit at an inlet temperature of 5°C and an outlet temperature of 50°C during rated operation, and highest at 11.5 L / min when supplying cooling water to a fuel cell unit at an inlet temperature of 45°C and an outlet temperature of 60°C during maximum heat output. In other words, the cooling water flow rate in the cooling channel needs to be controlled within a range of 2.7 L / min to 11.5 L / min per fuel cell unit. Since multiple fuel cell units are installed, a wider range of flow rate control is required. For example, if 10 fuel cell units are installed, the flow rate needs to be controlled within a range of 2.7 L / min to 115 L / min.

[0047] Furthermore, when the fuel cell unit is operated at partial load (e.g., 4kW), the cooling water flow rate needs to be reduced even further, requiring even broader flow rate control.

[0048] According to the fuel cell system 100 of Embodiment 1, the flow rate can be controlled even in a very wide flow rate range of 2.7 L / min to 115 L / min by controlling the pump 22 and the bypass path 23 described above. As a result, according to the fuel cell system 100 of Embodiment 1, the temperature of each of the multiple fuel cell units can be maintained within a temperature range suitable for operation, and the cooling water used to cool the fuel cell units can be recovered within a desired temperature range.

[0049] A more specific example of a fuel cell system 100 according to Embodiment 1 that can be operated under the following conditions is shown. • Hot water temperature from the fuel cell unit during fuel cell system operation: 50°C to 60°C • Inlet water temperature to the fuel cell unit during fuel cell system operation: 5°C to 45°C • Heat output per fuel cell unit: 8485W / unit at rated operation, 12000W / unit at maximum operation

[0050] Here, the fuel cell unit 10 is a fuel cell unit capable of partial load operation between 0kW and 10kW, and the amount of waste heat generated at 10kW is 12,000W per unit. The number of fuel cell units 10 installed in the fuel cell system 100 is 10. The pump 22 is a constant flow pump with a capacity of 60L / min. The opening degree of the throttle valve 12 inside the fuel cell unit 10 is controlled so that the temperature inside the fuel cell unit 10 remains within a certain range according to the amount of power generated inside the fuel cell unit 10. The control of the number of pumps 22 in operation and the opening degree of the throttle valve 24 in the bypass path 23 is as follows (a) to (c). (a) Control based on the discharge pressure of pump 22: Feedback control of the number of pumps 22 in operation and the opening degree of the throttle valve 24 so that the discharge pressure of pump 22 is 200 kPa. (b) Control based on the opening degree of the throttle valve 12 of the fuel cell unit 10: The flow rate in the fuel cell unit 10 is calculated, and the number of pumps 22 in operation and the opening degree of the throttle valve 24 are calculated. (c) Control based on the amount of power generated by the fuel cell unit 10: The required flow rate is calculated from the amount of power generated and the inlet temperature of the cooling water to the fuel cell unit 10, and the number of pumps 22 to operate and the opening degree of the throttle valve 24 are calculated.

[0051] Table 1A below shows an example of a fuel cell system 100 when one of the ten fuel cell units 10 is used for power generation. Table 1B shows an example of a fuel cell system 100 when seven of the ten fuel cell units 10 are used for power generation. Table 1C shows an example of a fuel cell system 100 when all ten fuel cell units 10 are used for power generation. In Tables 1A to 1C, "FC" stands for "fuel cell unit".

[0052] [Table 1A]

[0053] [Table 1B]

[0054] [Table 1C]

[0055] In any of the fuel cell systems described in Examples 1 to 9 above, the temperature of the cooling water at the outlet of the fuel cell unit 10 can be kept within the range of 50°C to 60°C.

[0056] [1-3. Effects, etc.] As described above, in Embodiment 1, the fuel cell system 100 comprises a plurality of fuel cell units 10, a cooling device 20 for cooling the plurality of fuel cell units 10, and a control device 30 for controlling the cooling device 20. The cooling device 20 includes a cooling channel 21 for supplying and recovering a cooling medium in parallel to the plurality of fuel cell units 10, and a pump 22 provided on the cooling channel 21 for adjusting the flow rate of the cooling medium. The cooling channel 21 includes a bypass path 23 that bypasses the pump 22 to return the cooling medium, which is discharged from the pump 22 and supplied to the plurality of fuel cell units 10, to the upstream side of the suction port 22a of the pump 22. The control device 30 controls the flow rate of the cooling medium in the cooling channel 21 by the pump 22 and the bypass path 23 based on the operating data of the fuel cell system 100 in order to keep the temperature of the plurality of fuel cell units 10 within a predetermined range.

[0057] This allows the fuel cell system 100 to control the flow rate of the cooling medium over a wide range. Therefore, the fuel cell system 100 is suitable for maintaining the temperature of each fuel cell unit 10 within an operating temperature range, while also recovering the cooling medium used to cool the fuel cell units 10 within a desired temperature range.

[0058] As in Embodiment 1, each of the multiple fuel cell units 10 may be equipped with a throttle valve 11 that adjusts the flow rate of the cooling medium supplied to the fuel cell unit 10.

[0059] This makes it easier to maintain the temperature of the fuel cell unit 10 within an appropriate range, thereby extending the lifespan of the fuel cell unit.

[0060] As in Embodiment 1, the bypass path 23 may include a throttle valve 24 for adjusting the flow rate of the cooling medium on the bypass path 23.

[0061] This makes it easier to control the flow rate of the cooling medium, allowing for control of the flow rate even when an inexpensive constant-flow pump is used as the pump.

[0062] As in Embodiment 1, each of the multiple fuel cell units 10 is equipped with a throttle valve 11 that adjusts the flow rate of the cooling medium supplied to the fuel cell unit 10, and the control device 30 may control the opening degree of a throttle valve 24 provided in the bypass path 23 based on at least one selected from the group consisting of the discharge pressure of the cooling medium in the pump 22, the opening degree of the throttle valve 11 provided in each of the multiple fuel cell units 10, and the power generation amount of each of the multiple fuel cell units 10.

[0063] This makes it easier to control the flow rate of the cooling medium, allowing for control of the flow rate even when an inexpensive constant-flow pump is used as the pump.

[0064] As in Embodiment 1, multiple pumps 22 are provided, and the multiple pumps 22 may be connected in parallel to one another.

[0065] This allows for a wider flow rate range for the cooling medium, making it possible to control the flow rate of the cooling medium even when, for example, an inexpensive constant-flow pump is used.

[0066] Even when multiple pumps 22 are provided and connected in parallel to each other, as in Embodiment 1, each of the multiple fuel cell units 10 may be equipped with a throttle valve 11 that adjusts the flow rate of the cooling medium supplied to the fuel cell unit 10. In this case, the control device 30 may control the number of operating pumps 22 based on at least one selected from the group consisting of the discharge pressure of the cooling medium in the pumps 22, the opening degree of the throttle valve 11 provided in each of the multiple fuel cell units 10, and the power generation amount of each of the multiple fuel cell units 10.

[0067] This allows for a wider flow rate range for the cooling medium, making it possible to control the flow rate of the cooling medium even when, for example, an inexpensive constant-flow pump is used.

[0068] Even when multiple pumps 22 are provided and connected in parallel to each other, as in Embodiment 1, each of the multiple fuel cell units 10 may be equipped with a throttle valve 11 that adjusts the flow rate of the cooling medium supplied to the fuel cell unit 10. In this case, the control device 30 may control the number of operating pumps 22 based on at least one selected from the group consisting of the discharge pressure of the cooling medium in the pumps 22, the opening degree of the throttle valve 11 provided in each of the multiple fuel cell units 10, and the power generation amount of each of the multiple fuel cell units 10. Furthermore, in this case, the bypass path 23 may be equipped with a throttle valve 24 that adjusts the flow rate of the cooling medium on the bypass path 23, and the control device 30 may control the opening degree of the throttle valve 24 provided in the bypass path 23 based on at least one selected from the group consisting of the discharge pressure of the cooling medium in the pumps 22, the opening degree of the throttle valve 11 provided in each of the multiple fuel cell units 10, and the power generation amount of each of the multiple fuel cell units 10.

[0069] This allows for precise control of the cooling medium flow rate, enabling flow rate control across a wide range of power output.

[0070] (Embodiment 2) The embodiments will be described below with reference to Figure 2.

[0071] [2-1. Structure] Figure 2 is a diagram illustrating the configuration of a fuel cell system according to Embodiment 2. As shown in Figure 2, the fuel cell system 200 according to Embodiment 2 comprises a plurality of fuel cell units 210, a cooling channel 221, a variable flow pump 222, and a control device 230. The cooling device 220 for cooling the plurality of fuel cell units 210 is composed of the cooling channel 221 and the variable flow pump 222. The cooling channel 221 is a channel for supplying and recovering a cooling medium to the plurality of fuel cell units 210 in parallel. The variable flow pump 222 is provided on the cooling channel 221 and adjusts the flow rate of the cooling medium. The control device 230 controls the cooling device 220.

[0072] In Embodiment 2, the fuel cell system 200 further includes a storage tank 240. The storage tank 240 stores a cooling medium. The cooling medium is, for example, water or antifreeze. Here, we will describe an example in which water is used as the cooling medium for cooling the fuel cell unit 210.

[0073] The fuel cell system 200 may further include a pressure gauge 250 provided on the cooling channel 221 for measuring the discharge pressure of the cooling water in the variable flow pump 222.

[0074] Each of the multiple fuel cell units 210 includes a fuel cell stack 211 and auxiliary equipment (not shown) necessary to operate the fuel cell stack 211. Figure 2 shows the first fuel cell unit 2101, the second fuel cell unit 2102, ... the nth fuel cell unit 210. n An example is shown in which n fuel cell units 210 (where n is an integer greater than or equal to 3) are connected to each other.

[0075] Examples of fuel cells include polymer electrolyte membrane fuel cells, solid oxide fuel cells, phosphoric acid fuel cells, and molten carbonate fuel cells. Fuel gas and oxidizer gas are supplied to the fuel cell stack 211, and electricity is generated by the reaction of the fuel gas and oxidizer gas in the fuel cell stack 211. The fuel supplied to the fuel cell stack 211 is, for example, pure hydrogen. In this case, the fuel cell system 200 further includes a tank (not shown) in which pure hydrogen is stored. Hydrogen gas as fuel gas is supplied from this tank to the fuel cell stack 211. The fuel used in the fuel cell system 200 may also include hydrocarbon gases such as methane gas, propane gas, and butane gas. In this case, the fuel cell system 200 includes a reformer. In the reformer, hydrogen-containing gas as fuel gas is produced from the hydrocarbon gas, and the hydrogen-containing gas is supplied to the fuel cell stack 211. Examples of fuels containing hydrocarbon gases are city gas and LPG.

[0076] The fuel cell unit 210 is connected to a load and supplies the generated power to the load. The load is installed in places such as factories, hospitals, schools, and commercial facilities.

[0077] Each of the multiple fuel cell units 210 is equipped with, for example, a throttle valve 212 that adjusts the flow rate of cooling water supplied to the fuel cell unit 210.

[0078] The fuel cell unit 210 may be a fuel cell operating at rated load, or a fuel cell capable of partial load operation. When the fuel cell unit 210 is a fuel cell capable of partial load operation, it is necessary to control the flow rate of the cooling water over a wider range. Therefore, the fuel cell system 200 according to Embodiment 1 may be more effective when the fuel cell unit 210 is a fuel cell capable of partial load operation.

[0079] As described above, the cooling channel 221 is a channel for supplying and recovering cooling water in parallel to multiple fuel cell units 210.

[0080] The cooling channel 221 may include, for example, a bypass path 223 that bypasses the variable flow pump 222 to return the cooling water, which is discharged from the variable flow pump 222 and supplied to the multiple fuel cell units 210, to the upstream side of the intake of the variable flow pump 222. The bypass path 223 may be provided with, for example, a throttle valve 224 to adjust the flow rate of the cooling water on the bypass path 223.

[0081] As described above, the variable flow pump 222 is installed on the cooling channel 221 and adjusts the flow rate of the cooling water. The variable flow pump 222 can change the flow rate within a range of, for example, 20 L / min to 120 L / min. By using the variable flow pump 222, the fuel cell system 200 according to Embodiment 2 can control the flow rate of the cooling water over a wide range and with precision. The operating amount of the variable flow pump 222 can be controlled, for example, by the frequency of the input pulse using inverter control.

[0082] As described above, the control device 230 controls the cooling device 220. The control device 230 controls the discharge rate of the variable flow pump 222 based on the operating data of the multiple fuel cell units 210 in order to keep the temperatures of the multiple fuel cell units 210 within a predetermined range.

[0083] The control device 230 may further control the operation of multiple fuel cell units 210. For example, the control device 230 may control a throttle valve 212 that adjusts the flow rate of cooling water supplied to the fuel cell units 210 according to the amount of power generated by the fuel cell units 210, or according to whether the fuel cell units 210 are in the initial stages of operation or not.

[0084] The operating data of the multiple fuel cell units 210 mentioned above includes, for example, the opening degree of the throttle valve 212 provided in each of the multiple fuel cell units 210, and the power generation amount of each of the multiple fuel cell units 210. Therefore, the control device 230 may control the discharge amount of the variable flow pump 222 based on at least one selected from the group consisting of the opening degree of the throttle valve 212 provided in each of the multiple fuel cell units 210 and the power generation amount of each of the multiple fuel cell units 210, in order to keep the temperatures of the multiple fuel cell units 210 within a predetermined range.

[0085] If the cooling channel 221 is provided with a bypass path 223 and a throttle valve 224, the control device 230 may, for example, control the throttle valve 224. In this case, the control device 230 may, for example, control the opening degree of the throttle valve 224 provided in the bypass path 223 based on at least one selected from the group consisting of the discharge pressure of the cooling water in the variable flow pump 222, the opening degree of the throttle valve 212 provided in each of the multiple fuel cell units 210, and the power generation amount of each of the multiple fuel cell units 210.

[0086] The control device 230 is, for example, a computer equipped with a memory device that stores a program necessary for operating the fuel cell system 200, and a processor that reads the program from the memory device and executes it.

[0087] Cooling water in the storage tank 240 is supplied from the storage tank 240 to the cooling channel and then supplied in parallel to multiple fuel cell units 210 via the variable flow pump 222. The cooling water's temperature rises due to the heat generated in each fuel cell unit 210 and it returns to the storage tank 240. The heated cooling water in the storage tank 240 may be used, for example, as hot water for hot water supply. The temperature of the cooling water in the storage tank 240 may be adjusted, for example, by introducing tap water.

[0088] [2-2. Operation] An example of the operation of the fuel cell system 200 will be described.

[0089] The control device 230 controls the discharge rate of the variable flow pump 222 based on the operating data of the multiple fuel cell units 210 in order to keep the temperatures of the multiple fuel cell units 210 within a predetermined range.

[0090] Specifically, the flow rate of cooling water in the cooling channel 21 is controlled to an appropriate range by controlling the discharge rate of the variable flow pump 222 based on, for example, at least one selected from the group consisting of the opening degree of the throttle valve 212 provided in each of the multiple fuel cell units 210 and the power generation amount of each of the multiple fuel cell units 210. By increasing the discharge rate of the variable flow pump 222, the flow rate of cooling water in the cooling channel 221 can be increased to a desired value. By decreasing the discharge rate of the variable flow pump 222, the flow rate of cooling water in the cooling channel 221 can be reduced to a desired value.

[0091] The fuel cell system 200 according to Embodiment 2 can control the flow rate of the cooling water to a desired value according to the operating status of the fuel cell system 100 by controlling the discharge amount of the variable flow pump 222 based on the operating data of a plurality of fuel cell units 210, as described above.

[0092] If a bypass path 223 and a throttle valve 224 are provided in the cooling passage 221, the throttle valve 224 may be controlled. In this case, the control device 230 may, for example, control the opening degree of the throttle valve 224 provided in the bypass path 223 based on at least one selected from the group consisting of the discharge pressure of the cooling water in the variable flow pump 222, the opening degree of the throttle valve 212 provided in each of the multiple fuel cell units 210, and the power generation amount of each of the multiple fuel cell units 210. By lowering the opening degree of the throttle valve 224 on the bypass path 223, the flow rate of the cooling water in the cooling passage 221 can be increased to a desired value. By increasing the opening degree of the throttle valve 224 on the bypass path 223, the flow rate of the cooling water in the cooling passage 221 can be reduced to a desired value.

[0093] As described above, in the fuel cell system 200 according to Embodiment 2, by combining the control of the discharge amount of the variable flow pump 222 with the control of the throttle valve 224 provided in the bypass path 223, the flow rate of the cooling water can be precisely controlled to a desired value according to the operating conditions of the fuel cell system 200.

[0094] Furthermore, the control device 230 can obtain information on the discharge pressure of the cooling water in the variable flow pump 222 from the pressure gauge 50. In addition, the control device 230 can obtain information on the opening degree of the throttle valve 212 of the fuel cell unit 210, and information on the power generation amount of each fuel cell unit 210 from each fuel cell unit 210.

[0095] For example, let's assume that fuel cell system 200 is a fuel cell system operated under the following conditions. • Hot water temperature from the fuel cell unit during fuel cell system operation: 50°C to 60°C • Inlet water temperature to the fuel cell unit during fuel cell system operation: 5°C to 45°C • Heat output per fuel cell unit: 8485W / unit at rated operation, 12000W / unit at maximum operation

[0096] In a fuel cell system under the above conditions, the cooling water flow rate is lowest at 2.7 L / min when supplying cooling water to a fuel cell unit at an inlet temperature of 5°C and an outlet temperature of 50°C during rated operation, and highest at 11.5 L / min when supplying cooling water to a fuel cell unit at an inlet temperature of 45°C and an outlet temperature of 60°C during maximum heat output. In other words, the cooling water flow rate in the cooling channel needs to be controlled within a range of 2.7 L / min to 11.5 L / min per fuel cell unit. Since multiple fuel cell units are installed, a wider range of flow rate control is required. For example, if 10 fuel cell units are installed, the flow rate needs to be controlled within a range of 2.7 L / min to 115 L / min.

[0097] Furthermore, when the fuel cell unit is operated at partial load (e.g., 4kW), the cooling water flow rate needs to be reduced even further, requiring even broader flow rate control.

[0098] According to the fuel cell system 200 of Embodiment 2, by controlling the discharge rate of the variable flow pump 222 and, if necessary, controlling the throttle valve 224 of the bypass path 223, the flow rate can be controlled even in the very wide flow rate range of 2.7 L / min to 115 L / min. As a result, according to the fuel cell system 200 of Embodiment 2, the temperature of each of the multiple fuel cell units can be maintained within a temperature range suitable for operation, and the cooling water used to cool the fuel cell units can be recovered within a desired temperature range.

[0099] A more specific example of a fuel cell system 200 according to Embodiment 2 that can be operated under the following conditions is shown. • Hot water temperature from the fuel cell unit during fuel cell system operation: 50°C to 60°C • Inlet water temperature to the fuel cell unit during fuel cell system operation: 5°C to 45°C • Heat output per fuel cell unit: 8485W / unit at rated operation, 12000W / unit at maximum operation

[0100] Here, the fuel cell unit 210 is a fuel cell unit capable of partial load operation between 0kW and 10kW, and the amount of waste heat generated at 10kW is assumed to be 12,000W per unit. The number of fuel cell units 10 installed in the fuel cell system 200 is assumed to be 10. The pump 222 is a variable flow pump with a flow rate of 20L / min to 120L / min. The opening degree of the throttle valve 212 in the fuel cell unit 210 is controlled so that the temperature inside the fuel cell unit 10 remains within a certain range according to the amount of power generated inside the fuel cell unit 10. The control of the number of variable flow pumps 222 in operation and the opening degree of the throttle valve 224 in the bypass path 223 is as follows (a) to (c). (a) Control based on the discharge pressure of pump 222: Feedback control of the operating volume of pump 222 and the opening degree of throttle valve 224 so that the discharge pressure of pump 222 is 200 kPa. (b) Control based on the opening degree of the throttle valve 212 of the fuel cell unit 210: Calculate the flow rate in the fuel cell unit 210 and calculate the operating amount of the pump 222 and the opening degree of the throttle valve 24. (c) Control based on the power generation amount of the fuel cell unit 210: The required flow rate is calculated from the power generation amount and the inlet temperature of the cooling water to the fuel cell unit 210, and the operating amount of the pump 222 and the opening degree of the throttle valve 224 are calculated.

[0101] Table 2A below shows an example of a fuel cell system 200 when one of the ten fuel cell units 210 is used for power generation. Table 2B shows an example of a fuel cell system 200 when seven of the ten fuel cell units 210 are used for power generation. Table 2C shows an example of a fuel cell system 200 when all ten fuel cell units 210 are used for power generation. In Tables 2A to 2C, "FC" stands for "fuel cell unit".

[0102] [Table 2A]

[0103] [Table 2B]

[0104] [Table 2C]

[0105] In any of the fuel cell systems 200 in the above examples 11 to 15, the temperature of the cooling water at the outlet of the fuel cell unit 210 can be kept within the range of 50°C to 60°C.

[0106] [2-3. Effects, etc.] As described above, in Embodiment 2, the fuel cell system 200 comprises a plurality of fuel cell units 210, a cooling device 220 for cooling the plurality of fuel cell units 210, and a control device 230 for controlling the cooling device 220. The cooling device 220 includes a cooling channel 221 for supplying and recovering a cooling medium in parallel to the plurality of fuel cell units 210, and a variable flow pump 222 provided on the cooling channel 221 for adjusting the flow rate of the cooling medium. The control device 230 controls the discharge amount of the variable flow pump 222 based on the operating data of the plurality of fuel cell units 210 in order to keep the temperature of the plurality of fuel cell units 10 within a predetermined range.

[0107] This allows the fuel cell system 200 to control the flow rate of the cooling medium over a wide range. Therefore, the fuel cell system 200 is suitable for maintaining the temperature of each fuel cell unit 210 within an operating temperature range, while also recovering the cooling medium used to cool the fuel cell units 210 within a desired temperature range.

[0108] As in Embodiment 2, each of the multiple fuel cell units 210 may be equipped with a throttle valve 211 that adjusts the flow rate of the cooling medium supplied to the fuel cell unit 210.

[0109] This makes it easier to maintain the temperature of the fuel cell unit 210 within an appropriate range, thereby extending the lifespan of the fuel cell unit.

[0110] As in Embodiment 2, the control device 230 may control the discharge amount of the variable flow pump 222 based on at least one selected from the group consisting of the opening degree of the throttle valve 212 provided in each of the fuel cell units 210 and the power generation amount of each of the fuel cell units 210, in order to keep the temperatures of the multiple fuel cell units 210 within a predetermined range.

[0111] This allows for precise control of the cooling medium flow rate, enabling flow rate control across a wide range of power output.

[0112] (Other embodiments) As described above, Embodiments 1 and 2 have been explained as examples of the technology disclosed in this application. However, the technology in this disclosure is not limited thereto and can also be applied to embodiments that have been modified, replaced, added, omitted, etc.

[0113] In the fuel cell systems of Embodiment 1 and Embodiment 2, the cooling water whose temperature has risen due to the heat generated in each fuel cell unit is returned to the storage tank and used, for example, as hot water for hot water supply. However, the cooled water whose temperature has risen may be cooled by a cooling tower and reused as cooling water. Also, in the fuel cell systems of Embodiment 1 and Embodiment 2, the temperature of the cooling water in the storage tank is adjusted by introducing tap water, but the temperature of the cooling water in the storage tank may be adjusted using a cooling tower. In other words, the fuel cell systems of Embodiment 1 and Embodiment 2 may be equipped with a cooling tower.

[0114] Below, a modified example of the fuel cell system of Embodiment 1, a fuel cell system equipped with a cooling tower, will be described.

[0115] Figure 3 is a configuration diagram showing a first modified example of the fuel cell system according to Embodiment 1. As shown in Figure 3, the fuel cell system 101 of the first modified example has a configuration in which a cooling tower 41 is provided instead of a storage tank 40 in the fuel cell system 100 shown in Figure 1. In this fuel cell system 101, the cooling water whose temperature has risen due to the heat generated in the fuel cell unit 10 is directly transported to the cooling tower 41 and cooled.

[0116] Figure 4 is a configuration diagram showing a second modified example of the fuel cell system according to Embodiment 1. As shown in Figure 4, the fuel cell system 102 of the second modified example is provided with a cooling tower 41 instead of a storage tank 40 in the fuel cell system 100 shown in Figure 1. Furthermore, in the fuel cell system 102 of the second modified example, a bypass path 25 is provided instead of a bypass path 23 as a bypass path that bypasses the pump 22. The bypass path 25 is provided with, for example, a throttle valve 26 that adjusts the flow rate of cooling water on the bypass path 25. The bypass path 25 is a path for returning the cooling water, which has been discharged from the pump 22 and supplied to the multiple fuel cell units 10, to the path for transporting the cooling water to the cooling tower 41, which is upstream of the intake port of the pump 22 and has had its temperature raised by the heat generated in the fuel cell units 10. Based on the operating data of the fuel cell system 102, the flow rate of cooling water in the cooling channel 21 is controlled by the pump 22 and the bypass path 25. The control device 30 controls, for example, the opening and closing of the pump 22 and the throttle valve 26 on the bypass path 25. By passing the surplus flow rate of cooling water for cooling each fuel cell unit 10 through the bypass path 25, the flow rate of cooling water to the cooling tower 41 can be increased, thereby ensuring cooling efficiency.

[0117] Figure 5 is a configuration diagram showing a third modified example of the fuel cell system according to Embodiment 1. As shown in Figure 5, the fuel cell system 103 of the third modified example has a configuration in which a cooling tower 41 is further provided in addition to the fuel cell system 100 shown in Figure 1. In this fuel cell system 103, the cooling water whose temperature has risen due to the heat generated in the fuel cell unit 10 is used for heat utilization in the storage tank 40 and then transported to the cooling tower 41 to be cooled.

[0118] Figure 6 is a configuration diagram showing a fourth modified example of the fuel cell system according to Embodiment 1. As shown in Figure 6, the fuel cell system 104 of the fourth modified example has a configuration in which a cooling tower 41 is further provided in addition to the fuel cell system 100 shown in Figure 1. In this fuel cell system 104, the cooling water whose temperature has risen due to the heat generated in the fuel cell unit 10 is used for heat utilization in the storage tank 40 and then transported to the cooling tower 41 to be cooled. Furthermore, in the fuel cell system 104 of the fourth modified example, a bypass path 25 is provided instead of the bypass path 23 as a bypass path that bypasses the pump 22. The bypass path 25 is provided with, for example, a throttle valve 26 to adjust the flow rate of the cooling water on the bypass path 25. The bypass path 25 is a path for returning the cooling water, which has been discharged from the pump 22 and supplied to the multiple fuel cell units 10, to the path for transporting the cooling water, which is upstream of the intake port of the pump 22 and whose temperature has risen due to the heat generated in the fuel cell unit 10, to the path for transporting the cooling water to the cooling tower 41. Based on the operating data of the fuel cell system 104, the pump 22 and the bypass path 25 control the flow rate of cooling water in the cooling channel 21. The control device 30 controls, for example, the opening and closing of the pump 22 and the throttle valve 26 on the bypass path 25. By passing the surplus flow rate of cooling water for cooling each fuel cell unit 10 through the bypass path 25, the flow rate of cooling water to the cooling tower 41 can be increased to ensure cooling efficiency.

[0119] Figure 7 is a configuration diagram showing a fifth modified example of the fuel cell system according to Embodiment 1. As shown in Figure 7, the fuel cell system 105 of the fifth modified example has a configuration in which a heat exchanger 42 is provided instead of a storage tank 40 in the fuel cell system 100 shown in Figure 1. In this case, the cooling water whose temperature has risen due to the heat generated in each fuel cell unit 10 is cooled by heat exchange with the secondary side cooling medium in the heat exchanger 42. The secondary side cooling medium is transported to the cooling tower 41 by a pump 43 and cooled.

[0120] Figure 8 is a configuration diagram showing a sixth modified example of the fuel cell system according to Embodiment 1. As shown in Figure 8, the fuel cell system 106 of the sixth modified example has a configuration in which a heat exchanger 42 is provided instead of a storage tank 40 in the fuel cell system 100 shown in Figure 1. In this case, the cooling water whose temperature has risen due to the heat generated in each fuel cell unit 10 is cooled by heat exchange with the secondary cooling medium in the heat exchanger 42. The secondary cooling medium is transported to a cooling tower 41 by a pump 43 and cooled. Furthermore, in the fuel cell system 106 of the sixth modified example, a bypass path 25 is provided instead of a bypass path 23 as a bypass path that bypasses the pump 22. The bypass path 25 is provided with, for example, a throttle valve 26 to adjust the flow rate of the cooling water on the bypass path 25. The bypass path 25 is a path for returning the cooling water, which has been discharged from the pump 22 and supplied to the multiple fuel cell units 10, to the path for transporting the cooling water, which has risen in temperature due to the heat generated in the fuel cell units 10, to the path upstream of the suction port of the pump 22 and is located in the path for transporting the cooling water to the heat exchanger 42. Based on the operating data of the fuel cell system 106, the pump 22 and bypass path 25 control the flow rate of cooling water in the cooling channel 21. The control device 30 controls, for example, the opening and closing of the pump 22 and the throttle valve 26 on the bypass path 25. By passing the surplus flow rate of cooling water for cooling each fuel cell unit 10 through the bypass path 25, the flow rate for heat exchange with the secondary cooling medium in the heat exchanger 42 can be increased, thereby improving the cooling efficiency.

[0121] Figure 9 is a configuration diagram showing a seventh modified example of the fuel cell system according to Embodiment 1. As shown in Figure 9, the fuel cell system 107 of the seventh modified example has a configuration in which a heat exchanger 42 is further provided in addition to the fuel cell system 100 shown in Figure 1. In this case, the cooling water whose temperature has risen due to the heat generated in each fuel cell unit 10 is used for heat utilization in the storage tank 40, and then cooled by heat exchange with the secondary side cooling medium in the heat exchanger 42. The secondary side cooling medium is transported to the cooling tower 41 by a pump 43 and cooled.

[0122] Figure 10 is a configuration diagram showing an eighth modified example of the fuel cell system according to Embodiment 1. As shown in Figure 10, the fuel cell system 108 of the eighth modified example has a configuration in which a heat exchanger 42 is further provided in the fuel cell system 100 shown in Figure 1. In this case, the cooling water whose temperature has risen due to the heat generated in each fuel cell unit 10 is used for heat utilization in the storage tank 40, and then cooled by heat exchange with the secondary side cooling medium in the heat exchanger 42. The secondary side cooling medium is transported to the cooling tower 41 by a pump 43 and cooled. Furthermore, in the fuel cell system 108 of the eighth modified example, a bypass path 25 is provided instead of the bypass path 23 as a bypass path that bypasses the pump 22. The bypass path 25 is provided with, for example, a throttle valve 26 that adjusts the flow rate of the cooling water on the bypass path 25. The bypass path 25 is a path for returning the cooling water, which is discharged from the pump 22 and supplied to the multiple fuel cell units 10, to the path for transporting the cooling water, which has been heated by the heat generated in the fuel cell units 10 and is located upstream of the pump 22's intake, to the path for transporting the cooling water to the heat exchanger 42. Based on the operating data of the fuel cell system 108, the pump 22 and the bypass path 25 control the flow rate of the cooling water in the cooling channel 21. The control device 30 controls, for example, the opening and closing of the throttle valve 26 on the pump 22 and the bypass path 25. By passing the surplus flow rate of cooling water for cooling each fuel cell unit 10 through the bypass path 25, the flow rate for heat exchange with the secondary cooling medium in the heat exchanger 42 can be increased, thereby improving the cooling efficiency.

[0123] The fuel cell systems of Embodiments 1 and 2 may be applied as systems that supply power in conjunction with solar power generation equipment, battery storage equipment, and commercial power sources. In this case, since the fuel cell systems of Embodiments 1 and 2 are used, for example, as a means of power generation to compensate for a shortage in power generation from solar power generation equipment, the operating conditions of the multiple fuel cell units vary, and more precise cooling is required for each fuel cell unit. Therefore, when the fuel cell systems of Embodiments 1 and 2 are applied as systems that supply power in conjunction with solar power generation equipment, battery storage equipment, and commercial power sources, the fuel cell systems of Embodiments 1 and 2 may be more effective.

[0124] (Note) Based on the above description of embodiments, the following technologies are disclosed.

[0125] (Technology 1) Multiple fuel cell units, A cooling device for cooling the aforementioned multiple fuel cell units, A control device for controlling the cooling device, A fuel cell system equipped with, The cooling device, A cooling channel for supplying and recovering a cooling medium in parallel to the plurality of fuel cell units, A pump provided on the cooling channel and for adjusting the flow rate of the cooling medium, Includes, The cooling channel includes a bypass path that bypasses the pump for returning the cooling medium, which is discharged from the pump and supplied to the plurality of fuel cell units, to the upstream side of the pump's suction port. The control device controls the flow rate of the cooling medium in the cooling channel by the pump and the bypass path based on the operating data of the fuel cell system in order to keep the temperatures of the plurality of fuel cell units within a predetermined range. Fuel cell system.

[0126] According to the fuel cell system of Technology 1, the temperature of each fuel cell unit can be maintained within a temperature range suitable for operation, while the cooling medium used to cool the fuel cell unit can be recovered within a desired temperature range.

[0127] (Technology 2) Each of the plurality of fuel cell units is equipped with a throttle valve that adjusts the flow rate of the cooling medium supplied to the fuel cell unit. The fuel cell system described in Technology 1.

[0128] According to the fuel cell system of Technology 2, it becomes easier to maintain the temperature of the fuel cell unit within an appropriate range, thus enabling a longer lifespan for the fuel cell unit.

[0129] (Technology 3) The bypass path includes a throttle valve for adjusting the flow rate of the cooling medium on the bypass path. A fuel cell system as described in Technology 1 or 2.

[0130] According to the fuel cell system of Technology 3, the flow rate of the cooling medium becomes easier to control, and the flow rate of the cooling medium can be controlled even when an inexpensive constant flow pump is used as the pump.

[0131] (Technology 4) Each of the plurality of fuel cell units is equipped with a throttle valve that adjusts the flow rate of the cooling medium supplied to the fuel cell unit. The control device controls the opening degree of the throttle valve provided in the bypass path based on at least one selected from the group consisting of the discharge pressure of the cooling medium in the pump, the opening degree of the throttle valve provided in each of the plurality of fuel cell units, and the power generation amount of each of the plurality of fuel cell units. The fuel cell system described in Technology 3.

[0132] According to the fuel cell system of Technology 4, the flow rate of the cooling medium becomes easier to control, and the flow rate of the cooling medium can be controlled even when an inexpensive constant flow pump is used as the pump.

[0133] (Technology 5) Multiple pumps are provided, The aforementioned multiple pumps are connected to each other in parallel. A fuel cell system as described in any one of the technical items 1 to 4.

[0134] According to the fuel cell system of Technology 5, the flow rate range of the cooling medium can be widened, so the flow rate of the cooling medium can be controlled even when, for example, an inexpensive constant flow pump is used as the pump.

[0135] (Technology 6) Each of the plurality of fuel cell units is equipped with a throttle valve that adjusts the flow rate of the cooling medium supplied to the fuel cell unit. The control device controls the number of operating pumps based on at least one selected from the group consisting of the discharge pressure of the cooling medium in the pumps, the opening degree of the throttle valve provided in each of the fuel cell units, and the power generation amount of each of the fuel cell units. The fuel cell system described in Technology 5.

[0136] According to the fuel cell system of Technology 6, the flow rate of the cooling medium can be precisely controlled, allowing for flow rate control over a wide range of power output.

[0137] (Technology 7) The bypass path is equipped with a throttle valve that adjusts the flow rate of the cooling medium on the bypass path. The control device controls the opening degree of the throttle valve provided in the bypass path based on at least one selected from the group consisting of the discharge pressure of the cooling medium in the pump, the opening degree of the throttle valve provided in each of the plurality of fuel cell units, and the power generation amount of each of the plurality of fuel cell units. The fuel cell system described in Technology 6.

[0138] According to the fuel cell system of Technology 7, the flow rate of the cooling medium can be precisely controlled, allowing for flow rate control over a wide range of power output.

[0139] (Technology 8) Multiple fuel cell units, A cooling device for cooling the aforementioned multiple fuel cell units, A control device for controlling the cooling device, Equipped with, The cooling device, A cooling channel for supplying and recovering a cooling medium in parallel to the plurality of fuel cell units, A variable flow pump provided on the cooling channel and for adjusting the flow rate of the cooling medium, Includes, The control device controls the discharge amount of the variable flow pump based on the operating data of the plurality of fuel cell units in order to keep the temperatures of the plurality of fuel cell units within a predetermined range. Fuel cell system.

[0140] According to the fuel cell system of Technology 8, the temperature of each fuel cell unit can be maintained within a temperature range suitable for operation, while the cooling medium used to cool the fuel cell unit can be recovered within a desired temperature range.

[0141] (Technology 9) Each of the plurality of fuel cell units is equipped with a throttle valve that adjusts the flow rate of the cooling medium supplied to the fuel cell unit. The fuel cell system described in Technology 8.

[0142] According to the fuel cell system of Technology 9, it becomes easier to maintain the temperature of the fuel cell unit within an appropriate range, thus enabling a longer lifespan for the fuel cell unit.

[0143] (Technology 10) The control device controls the discharge amount of the variable flow pump based on at least one selected from the group consisting of the opening degree of the throttle valve provided in each of the fuel cell units and the power generation amount of each of the fuel cell units, in order to keep the temperature of the plurality of fuel cell units within a predetermined range. The fuel cell system described in Technical 9.

[0144] According to the fuel cell system of Technology 10, the flow rate of the cooling medium can be precisely controlled, allowing for flow rate control over a wide range of power output. [Industrial applicability]

[0145] The technology disclosed herein allows for the optimization of cooling for each fuel cell unit in a fuel cell system comprising multiple fuel cell units, making it applicable to systems where extending the lifespan of fuel cell units and improving thermal efficiency are required. Furthermore, the fuel cell system disclosed herein is applicable to solar power generation facilities, fuel cell storage facilities, and systems that supply power in conjunction with commercial power sources. The technology disclosed herein is applicable to environmental protection initiatives such as RE100 (Renewable Energy 100%). [Explanation of Symbols]

[0146] 100, 101, 102, 103, 104, 105, 106, 107, 108, 200 Fuel cell systems 10,210 fuel cell units 11,211 fuel cell stacks 12,212 throttle valves 20,220 Cooling equipment 21,221 Cooling channels 22 pumps 222 Variable flow pump 23, 25, 223 Bypass Route 24, 26, 224 throttle valve 30,230 control devices 40,240 storage tanks 41 Cooling Tower 42 Heat exchanger 43 pumps 50,250 pressure gauge

Claims

1. Multiple fuel cell units, A cooling device for cooling the aforementioned multiple fuel cell units, A control device for controlling the cooling device, A fuel cell system equipped with, The cooling device, A cooling channel for supplying and recovering a cooling medium in parallel to the plurality of fuel cell units, A pump provided on the cooling channel and for adjusting the flow rate of the cooling medium, Includes, The cooling channel includes a bypass path that bypasses the pump for returning the cooling medium, which is discharged from the pump and supplied to the plurality of fuel cell units, to the upstream side of the pump's suction port. The control device controls the flow rate of the cooling medium in the cooling channel by the pump and the bypass path based on the operating data of the fuel cell system in order to keep the temperatures of the plurality of fuel cell units within a predetermined range. Fuel cell system.

2. Each of the plurality of fuel cell units is equipped with a throttle valve that adjusts the flow rate of the cooling medium supplied to the fuel cell unit. The fuel cell system according to claim 1.

3. The bypass path includes a throttle valve for adjusting the flow rate of the cooling medium on the bypass path. The fuel cell system according to claim 1.

4. Each of the plurality of fuel cell units is equipped with a throttle valve that adjusts the flow rate of the cooling medium supplied to the fuel cell unit. The control device controls the opening degree of the throttle valve provided in the bypass path based on at least one selected from the group consisting of the discharge pressure of the cooling medium in the pump, the opening degree of the throttle valve provided in each of the plurality of fuel cell units, and the power generation amount of each of the plurality of fuel cell units. The fuel cell system according to claim 3.

5. Multiple pumps are provided, The aforementioned multiple pumps are connected to each other in parallel. The fuel cell system according to claim 1.

6. Each of the plurality of fuel cell units is equipped with a throttle valve that adjusts the flow rate of the cooling medium supplied to the fuel cell unit. The control device controls the number of operating pumps based on at least one selected from the group consisting of the discharge pressure of the cooling medium in the pumps, the opening degree of the throttle valve provided in each of the fuel cell units, and the power generation amount of each of the fuel cell units. The fuel cell system according to claim 5.

7. The bypass path is equipped with a throttle valve that adjusts the flow rate of the cooling medium on the bypass path. The control device controls the opening degree of the throttle valve provided in the bypass path based on at least one selected from the group consisting of the discharge pressure of the cooling medium in the pump, the opening degree of the throttle valve provided in each of the plurality of fuel cell units, and the power generation amount of each of the plurality of fuel cell units. The fuel cell system according to claim 6.

8. Multiple fuel cell units, A cooling device for cooling the aforementioned multiple fuel cell units, A control device for controlling the cooling device, Equipped with, The cooling device, A cooling channel for supplying and recovering a cooling medium in parallel to the plurality of fuel cell units, A variable flow pump provided on the cooling channel and for adjusting the flow rate of the cooling medium, Includes, The control device controls the discharge amount of the variable flow pump based on the operating data of the plurality of fuel cell units in order to keep the temperatures of the plurality of fuel cell units within a predetermined range. Fuel cell system.

9. Each of the plurality of fuel cell units is equipped with a throttle valve that adjusts the flow rate of the cooling medium supplied to the fuel cell unit. The fuel cell system according to claim 8.

10. The control device controls the discharge amount of the variable flow pump based on at least one selected from the group consisting of the opening degree of the throttle valve provided in each of the fuel cell units and the power generation amount of each of the fuel cell units, in order to keep the temperature of the plurality of fuel cell units within a predetermined range. The fuel cell system according to claim 9.

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