Fuel cell system

Abstract

A fuel cell system is provided with a stack unit including a fuel cell stack, and a hydrogen tank module. The hydrogen tank module includes: a plurality of hydrogen tanks each provided with a valve; a temperature sensor for measuring the temperature of hydrogen gas supplied from each hydrogen tank to the stack unit; and a control device that switches the supply state of hydrogen gas from each hydrogen tank to the stack unit by controlling the valve of each hydrogen tank. The control device selectively uses one of the plurality of hydrogen tanks as an on-site supply tank for supplying hydrogen gas to the stack unit, and switches the on-site supply tank to another hydrogen tank when the hydrogen gas temperature measured by the temperature sensor becomes equal to or less than a reference temperature.

Description

Technical Field

[0001] The present disclosure relates to fuel cell systems. Background Art

[0002] Conventionally, a fuel cell system that supplies hydrogen from a plurality of hydrogen tanks to a fuel cell stack is known (for example, Japanese Patent Application Laid-Open No. 2018-113154).

[0003] However, the inventors of the present disclosure have found that if the valves of multiple hydrogen tanks are opened and closed at the same time, the internal temperature of all hydrogen tanks decreases as hydrogen is consumed. In addition, the inventors of the present disclosure have found that there is a possibility that the parts used by the hydrogen supply object are overcooled by hydrogen and a defect occurs in the parts. Therefore, it is desirable to supply hydrogen without overcooling the parts of the hydrogen supply object. Summary of the invention

[0004] (1) According to one aspect of the present disclosure, there is provided a fuel cell system including: a cell stack unit including a fuel cell group; and a hydrogen tank module.

[0005] The hydrogen tank module comprises: a plurality of hydrogen tanks, each of which is provided with a valve; a temperature sensor for measuring the temperature of the hydrogen gas supplied from each hydrogen tank to the battery stack unit; and a control device for switching the supply state of the hydrogen gas from each hydrogen tank to the battery stack unit by controlling the valve of each hydrogen tank.

[0006] The control device selectively uses one of the plurality of hydrogen tanks as a current supply tank for supplying the hydrogen gas to the battery stack unit, and switches the current supply tank to another hydrogen tank when the hydrogen gas temperature measured by the temperature sensor becomes lower than a reference temperature.

[0007] According to this fuel cell system, when the temperature of hydrogen gas supplied to the cell stack unit becomes equal to or lower than the reference temperature, the current supply tank is switched, so that it is possible to suppress the hydrogen gas from excessively cooling the components of the cell stack unit.

[0008] (2) It can also be constructed as follows: on the basis of the above-mentioned fuel cell system, the above-mentioned multiple hydrogen tanks are arranged in parallel with respect to the hydrogen flow outlet of the above-mentioned hydrogen tank module, and each hydrogen tank is provided with an internal tank temperature sensor for measuring the temperature inside each hydrogen tank as the above-mentioned temperature sensor, and the above-mentioned control device selects one from the above-mentioned multiple hydrogen tanks in the order of the internal tank temperature from high to low as the above-mentioned current supply tank for use in sequence.

[0009] According to this fuel cell system, when a plurality of hydrogen tanks are provided in parallel, the tanks are used in descending order of internal temperature as the current supply tanks, thereby suppressing frequent switching of the current supply tanks.

[0010] (3) It can also be configured as follows: based on the above-mentioned fuel cell system, the above-mentioned multiple hydrogen tanks are arranged in series relative to the hydrogen flow outlet of the above-mentioned hydrogen tank module, and the above-mentioned control device selects one of the above-mentioned multiple hydrogen tanks in order from near to far from the above-mentioned hydrogen flow outlet as the above-mentioned current supply tank to be used in sequence.

[0011] According to this fuel cell system, when a plurality of hydrogen tanks are arranged in series, they are used as current supply tanks in order from closest to the hydrogen outlet, thereby suppressing a rapid drop in hydrogen gas temperature and preventing frequent switching of current supply tanks.

[0012] Features, advantages, and technical and industrial significance of exemplary embodiments of the present invention are described below with reference to the accompanying drawings, in which like reference numerals represent like elements. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 is a conceptual diagram showing the structure of a fuel cell system;

[0014] Figure 2 is an explanatory diagram showing the structure of the hydrogen tank module in the first embodiment;

[0015] Figure 3 is a timing chart showing an example of valve control of the hydrogen tank module in the first embodiment;

[0016] Figure 4 is an explanatory diagram showing the structure of a hydrogen tank module in the second embodiment;

[0017] Figure 5 is a timing chart showing an example of valve control of the hydrogen tank module in the second embodiment;

[0018] Figure 6 It is an explanatory diagram showing the structure of a hydrogen tank module in the third embodiment. DETAILED DESCRIPTION

[0019] Figure 1 1 is a conceptual diagram showing the structure of the fuel cell system 10. The fuel cell system 10 comprises: an anode gas supply system including a hydrogen tank module 100; a battery stack unit 200 including a fuel cell group 210; and a cathode gas supply system including an air compressor 300. The fuel cell group 210 generates electricity through a fuel cell reaction of hydrogen supplied as an anode gas and oxygen supplied as a cathode gas. In addition, the anode gas supply system may also be configured to have an ejector and an anode exhaust gas circulation system. In addition, the cathode gas supply system may also be configured to have various valves and flow distribution pipes.

[0020] Figure 21 is an explanatory diagram showing the structure of the hydrogen tank module 100 in the first embodiment. The hydrogen tank module 100 includes a hydrogen inlet 111, a hydrogen outlet 112, an inflow side connection portion 121, an outflow side connection portion 122, a decompression unit 130, a plurality of hydrogen tanks 140, and a control device 150. A valve unit 160 is provided in each hydrogen tank 140.

[0021] The hydrogen inlet 111 is connected to the inlet side connection part 121 through the inlet pipe 171. The inlet side connection part 121 is a branch connection part including a plurality of branch ports, and each branch port is connected to the gas inlet of each valve unit 160 via a connecting pipe 172. The outflow side connection part 122 is a collective connection part including a plurality of inlets, and each inlet is connected to the gas outlet of each valve unit 160 via a connecting pipe 173. The outflow side connection part 122 is connected to the hydrogen outlet 112 through an outflow pipe 174. A decompression unit 130 is provided in the middle of the outflow pipe 174. The decompression unit 130 includes a decompression valve, which decompresses the pressure of the hydrogen gas supplied to the hydrogen outlet 112 to a preset set pressure.

[0022] In the first embodiment, a plurality of hydrogen tanks 140 are connected in parallel with respect to the hydrogen flow outlet 112 of the hydrogen tank module 100. Generally speaking, the hydrogen tank module 100 is configured to include N hydrogen tanks 140. N is an integer greater than 2, and in the first embodiment, N=4. Hereinafter, in order to distinguish the four hydrogen tanks 140 included in the hydrogen tank module 100, they are respectively referred to as "tank #1", "tank #2", "tank #3", and "tank #4".

[0023] The valve unit 160 has an inflow pipe 161, an outflow pipe 162, and a common pipe 163. The inflow pipe 161 is connected to the gas inlet of the valve unit 160. The outflow pipe 162 is connected to the gas outlet of the valve unit 160. The common pipe 163 is connected to the inflow pipe 161 and the outflow pipe 162, and is connected to the inside of the hydrogen tank 140 via the joint of the hydrogen tank 140. A check valve and a filter are respectively provided in the inflow pipe 161 and the outflow pipe 162. A solenoid valve 165 is provided in the common pipe 163, and an on-off valve 164 is provided in the outflow pipe 162.

[0024] The on-off valve 164 is a manual valve for maintenance, and is always maintained in an open state when the hydrogen tank module 100 is in use. The solenoid valve 165 is switched between an open state and a closed state by the control device 150 when the hydrogen tank module 100 is in use. When the solenoid valve 165 is in an open state, the hydrogen in the hydrogen tank 140 flows out to the outside via the common pipe 163 and the outflow pipe 162. When the solenoid valve 165 is in a closed state, the outflow of hydrogen in the hydrogen tank 140 stops. Among them, if hydrogen is supplied to the gas inlet of the valve unit 160 when the solenoid valve 165 is in a closed state, hydrogen is introduced to the downstream side via the inflow pipe 161 and the outflow pipe 162. The latter characteristic is utilized in the series configuration of the second embodiment described later.

[0025] The valve unit 160 also has an in-tank temperature sensor 166 for measuring the temperature of the hydrogen gas in the interior of the hydrogen tank 140. The temperature measured by the in-tank temperature sensor 166 is referred to as the "in-tank temperature". The in-tank temperature sensor 166 is used as a temperature sensor for measuring the temperature of the hydrogen gas supplied from each hydrogen tank 140 to the battery stack unit 200. In addition, instead of providing the in-tank temperature sensor 166 in each hydrogen tank 140, a temperature sensor may be provided, for example, in the middle of the outflow pipe 174 to measure the temperature of the hydrogen gas supplied to the battery stack unit 200.

[0026] Pressure sensors 121p and 122p for measuring the pressure of hydrogen gas are provided at the inflow-side connection portion 121 and the outflow-side connection portion 122, respectively. A pressure sensor for measuring the pressure of hydrogen gas before and after decompression may also be provided at the decompression unit 130. However, some of these pressure sensors may be omitted.

[0027] The control device 150 uses the hydrogen temperature measured by the tank temperature sensor 166 to control the operation of the hydrogen tank module 100. Specifically, the control device 150 switches the supply state of hydrogen from each hydrogen tank 140 to the battery stack unit 200 by controlling the opening and closing of the solenoid valve 165 of the valve unit 160 provided in each hydrogen tank 140. In addition, unless otherwise specified, the term "valve" in this disclosure refers to the solenoid valve 165.

[0028] The hydrogen tank 140 used in this embodiment is a so-called Type 4 tank, which is a high-pressure hydrogen container for FCV with an operating pressure of 70 MPa or less. If hydrogen is continuously supplied to the battery stack unit 200 from such a hydrogen tank 140, there is a possibility that the temperature of the supplied hydrogen will drop to around minus 40°C. On the other hand, for the components used in the battery stack unit 200, there are many components whose lower limit of operating temperature is in the range of minus 30°C to minus 10°C, and if they are exposed to hydrogen at a lower temperature than this, adverse conditions may occur. Therefore, in the first embodiment, the control device 150 performs valve control of the hydrogen tank module 100 so that the temperature of the hydrogen supplied from the hydrogen tank 140 is in a range higher than the lower limit of the operating temperature of the components of the battery stack unit 200.

[0029] Figure 3 : is a timing chart showing an example of valve control of the hydrogen tank module 100 in the first embodiment. Figure 3 , the hydrogen supply pressure Psup, the hydrogen supply temperature Tsup, and the open / closed states of the solenoid valves 165 of the four tanks #1 to #4 are shown. The hydrogen supply pressure Psup is the pressure of the hydrogen gas supplied from each hydrogen tank 140 to the decompression unit 130. The hydrogen supply temperature Tsup is the temperature of the hydrogen gas supplied from each hydrogen tank 140 to the decompression unit 130. In one embodiment, the tank internal temperature of each hydrogen tank 140 measured by the tank internal temperature sensor 166 may be used as the hydrogen supply temperature Tsup.

[0030] In the first embodiment, the control device 150 selects one of the multiple hydrogen tanks 140 in descending order of the internal temperature of the tank and sequentially uses it as a current supply tank. The "current supply tank" refers to a hydrogen tank that is supplying hydrogen to the battery stack unit 200. Figure 3 In the example of FIG. 1 , it is assumed that the tank internal temperatures are high in the order of tanks #1 to #4. It is preferable to use a value measured at the time of startup of the fuel cell system 10 as the tank internal temperature.

[0031] exist Figure 3 During the period from time t1 to t2, tank #1 with the highest temperature inside is selected and used among tanks #1 to #4 as the current supply tank. During this period, the solenoid valve 165 of tank #1 is open, and the solenoid valves 165 of other tanks #2 to #4 are closed. The supply hydrogen pressure Psup decreases monotonically from the initial pressure of tank #1. At time t2, the supply hydrogen temperature Tsup drops below a preset reference temperature Tref. The reference temperature Tref is preferably set to a value higher than the highest value Tlim among the lower limits of the operating temperatures of the multiple components cooled by hydrogen gas among the multiple components of the battery stack unit 200.

[0032] At time t2, the control device 150 switches the current supply tank from tank #1 to tank #2, and corresponding to the switching action, the supply hydrogen pressure Psup rises to approximately the initial pressure of tank #2. In addition, the supply hydrogen temperature Tsup also rises slightly at time t2, and then decreases again. During the period from time t2 to t3, the solenoid valve 165 of tank #2 is open, and the solenoid valves 165 of other tanks #1, #3, and #4 are closed. Among them, the solenoid valve 165 of tank #1, which was originally used as the current supply tank, can also be maintained open. This is because, during the period from time t2 to t3, the pressure of tank #2 is higher than that of tank #1, so even if the solenoid valve 165 of tank #1 becomes open, in fact, only tank #2 functions as the current supply tank. In addition, since a check valve is provided in the outflow pipe 162 of the valve unit 160, there is no worry that hydrogen will flow into tank #1 even if the solenoid valve 165 of tank #1 becomes open. The supply hydrogen pressure Psup decreases monotonically again from time t2. At time t3, the supply hydrogen temperature Tsup drops to or below the reference temperature Tref.

[0033] During the period from time t3 to time t4, tank #3 is used as the current supply tank. During the period from time t4 to time t5, tank #4 is used as the current supply tank. The operation during the above period is almost the same as the operation during the period from time t2 to time t3, so the description is omitted.

[0034] As described above, in the first embodiment, when the temperature of the hydrogen gas supplied to the battery stack unit 200 becomes equal to or lower than the reference temperature Tref, the current supply tank is switched. Therefore, it is possible to suppress the hydrogen gas from excessively cooling the components of the battery stack unit 200 .

[0035] Furthermore, in the first embodiment, one of the multiple hydrogen tanks 140 is selected in the order of the temperature inside the tank from high to low to be used in sequence as a current supply tank. However, the order of selection is not limited thereto, and any one of the multiple hydrogen tanks 140 may be selected as the current supply tank. Among them, in the case where multiple hydrogen tanks 140 are arranged in parallel, they are used as current supply tanks in the order of the temperature inside the tank from high to low, thereby suppressing the frequent switching of the current supply tanks. In addition, it is inferred that the higher the temperature inside the tank, the more hydrogen remaining, so if they are used as current supply tanks in the order of the temperature inside the tank from high to low, multiple hydrogen tanks 140 can be used without bias.

[0036] Figure 41 is an explanatory diagram showing the internal structure of the hydrogen tank module 100 in the second embodiment. The structure of the fuel cell system 10 in the second embodiment is the same as that in the first embodiment. The difference between the second embodiment and the first embodiment is that the multiple hydrogen tanks 140 of the hydrogen tank module 100 are arranged in series with respect to the hydrogen flow outlet 112. That is, tank #1 is connected to tank #2 via a connecting pipe 175. Similarly, tank #2 is connected to tank #3 via a connecting pipe 176, and tank #3 is connected to tank #4 via a connecting pipe 177.

[0037] Figure 5 1 is a timing chart showing an example of valve control of the hydrogen tank module 100 in the second embodiment. In the second embodiment, the control device 150 selects one of the multiple hydrogen tanks 140 in order from near to far from the hydrogen flow outlet 112 as a current supply tank to be used in sequence. "Closer to the hydrogen flow outlet 112" means being arranged further downstream in the series hydrogen flow path. Figure 4 In the example, the tanks are arranged in the order of tanks #4, #3, #2, and #1, from near to far from the hydrogen flow outlet 112.

[0038] exist Figure 5 During the period from time t11 to t12, tank #4, which is closest to the hydrogen outlet 112, is selected and used as the current supply tank. During this period, the solenoid valve 165 of tank #4 is open, and the solenoid valves 165 of the other tanks #1 to #3 are closed. The changes in the supply hydrogen pressure Psup and the supply hydrogen temperature Tsup are related to Figure 3 The example of the first embodiment shown is almost the same.

[0039] During the period from time t12 to t13, tank #3 is used as the current supply tank. During the period from time t13 to t14, tank #2 is used as the current supply tank. During the period from time t14 to t15, tank #1 is used as the current supply tank.

[0040] In the above second embodiment, similar to the first embodiment, the current supply tank is switched when the temperature of the hydrogen gas supplied to the battery stack unit 200 becomes below the reference temperature Tref. Therefore, it is possible to prevent the hydrogen gas from excessively cooling the components of the battery stack unit 200. In addition, in the second embodiment, when a plurality of hydrogen tanks 140 are arranged in series, they are used as current supply tanks in the order from near to far from the hydrogen outflow port 112. As a result, it is possible to prevent a rapid drop in the temperature of the hydrogen gas, and to prevent frequent switching of the current supply tank. In addition, the order of selection of the hydrogen tanks 140 in the second embodiment is not limited thereto, and any one of the plurality of hydrogen tanks 140 may be selected as the current supply tank.

[0041] Figure 6is an explanatory diagram showing the internal structure of the hydrogen tank module in the third embodiment. In the third embodiment, two Figure 2 The hydrogen tank modules 100 of the same structure as shown are used. The hydrogen flow outlets 112 of the two hydrogen tank modules 100a and 100b are connected to the common hydrogen flow outlet 180. Hydrogen gas is supplied to the battery stack unit 200 from the common hydrogen flow outlet 180. The eight hydrogen tanks 140 included in the two hydrogen tank modules 100a and 100b are connected in parallel with respect to the common hydrogen flow outlet 180.

[0042] The control devices 150a and 150b of the two hydrogen tank modules 100a and 100b are configured to communicate with each other and function as a control device. As in the first embodiment, the control devices 150a and 150b select one of the multiple hydrogen tanks 140 in descending order of the internal temperature of the tank to be used as the current supply tank in sequence. The valve control method in the third embodiment is the same as Figure 3 The method of the first embodiment shown is almost the same, so the description is omitted.

[0043] In the third embodiment, similarly to the first embodiment, when the temperature of the hydrogen gas supplied to the battery stack unit 200 becomes lower than the reference temperature Tref, the current supply tank is switched. Therefore, it is possible to suppress the hydrogen gas from excessively cooling the components of the battery stack unit 200. In addition, when a plurality of hydrogen tanks 140 are provided in parallel, they are used as current supply tanks in the order of the temperature inside the tank from high to low, so that it is possible to suppress frequent switching of the current supply tank.

[0044] In each of the above-described embodiments, the cell stack unit 200 is used as the hydrogen supply target of the hydrogen tank module 100. However, the present disclosure can also be applied to the case of supplying hydrogen to any supply target device other than the cell stack unit 200.

[0045] Other ways:

[0046] The present disclosure is not limited to the above-mentioned embodiments, and can be implemented in various ways without departing from the scope of the present invention. For example, the present disclosure can also be implemented in the following manner (aspect). In order to solve part or all of the problems of the present disclosure, or to achieve part or all of the effects of the present disclosure, the technical features in the above-mentioned embodiments corresponding to the technical features in the various methods described below can be appropriately replaced or combined. In addition, as long as it is not stated that the technical feature is necessary in this specification, it can be appropriately deleted.

[0047] The present disclosure may also be implemented in various forms other than a fuel cell system or a control method thereof, for example, a hydrogen tank module, a control method thereof, a computer program for executing control of a fuel cell system or a hydrogen tank module, a non-temporary non-temporary storage medium having a computer program recorded thereon, and the like.

Claims

1. A fuel cell system, wherein: The fuel cell system comprises: A battery stack unit, including a fuel cell stack; and Hydrogen tank module, The hydrogen tank module comprises: A plurality of hydrogen tanks, each provided with a valve; a temperature sensor for measuring the temperature of hydrogen gas supplied from each hydrogen tank to the battery stack unit; and a control device that switches the supply state of the hydrogen gas from each hydrogen tank to the battery stack unit by controlling the valve of each hydrogen tank, The control device selectively uses one of the plurality of hydrogen tanks as a current supply tank for supplying the hydrogen gas to the battery stack unit, and switches the current supply tank to another hydrogen tank when the hydrogen gas temperature measured by the temperature sensor becomes equal to or lower than a reference temperature.

2. The fuel cell system according to claim 1, wherein: The plurality of hydrogen tanks are arranged in parallel with respect to the hydrogen outlet of the hydrogen tank module, Each hydrogen tank is provided with an internal tank temperature sensor for measuring the temperature inside the hydrogen tank as the temperature sensor. The control device selects one of the plurality of hydrogen tanks in descending order of internal tank temperature as the current supply tank to be used sequentially.

3. The fuel cell system according to claim 1, wherein: The plurality of hydrogen tanks are arranged in series with respect to the hydrogen outlet of the hydrogen tank module, The control device selects one of the plurality of hydrogen tanks in order from closest to the hydrogen outflow port as the current supply tank for sequential use.

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