JP-2026074550-A - Fuel cell system
Abstract
[Problem] To suppress deterioration of the fuel cell due to oxidation by adjusting the concentration of fuel gas supplied from the ejector to the fuel cell, even if the pressure of the fuel gas supplied to the ejector decreases. [Solution] The fuel cell system 1 comprises an FC stack 11, a hydrogen gas supply passage 31, a hydrogen off-gas circulation passage 33, an ejector 54, an exhaust drain valve 57, a hydrogen gas pressure sensor 16, and a control device 20. The control device 20 variably controls the time ratio of the open time and closed time per control cycle of the exhaust drain valve 57, controlling the number of opening and closing operations of the exhaust drain valve 57 per unit time by keeping the open time constant and variably controlling the closed time. The control device 20 controls the number of opening and closing operations of the exhaust drain valve 57 according to the pressure measurement value of the pressure sensor 16 in order to adjust the concentration of hydrogen gas in the hydrogen off-gas circulated to the hydrogen gas supply passage 31 via the hydrogen off-gas circulation passage 33. [Selection Diagram] Figure 1
Inventors
- 浅沼 大作
Assignees
- 愛三工業株式会社
Dates
- Publication Date
- 20260507
- Application Date
- 20241021
Claims (4)
- In a fuel cell system equipped with a fuel cell that generates electricity by receiving fuel gas and oxidizer gas, A fuel gas supply passage for supplying the fuel gas to the fuel cell, A fuel off-gas discharge passage for discharging fuel off-gas from the fuel cell to the outside, A fuel off-gas circulation passage that circulates at least a portion of the fuel off-gas from the fuel off-gas discharge passage to the fuel gas supply passage, A fuel gas supply means is arranged in the fuel gas supply passage and for supplying the fuel gas, An ejector is located downstream of the fuel gas supply means in the fuel gas supply passage and mixes the fuel gas supplied by the fuel gas supply means with the fuel off gas circulating in the fuel off gas circulation passage and discharges it; An exhaust drain valve is provided in the fuel off-gas discharge passage for discharging the fuel off-gas to the outside, A pressure sensor is provided in the fuel gas supply passage for measuring the pressure of the fuel gas upstream of the ejector. The system includes a control device for controlling the exhaust drain valve, The control device controls the time ratio of the open time to the closed time per control cycle of the exhaust and drain valve in a variable manner, and is configured to control the number of opening and closing operations of the exhaust and drain valve per unit time by keeping the open time constant and controlling the closed time in a variable manner. The fuel cell system is characterized in that the control device controls the number of times the exhaust drain valve is opened and closed according to the pressure measurement value of the pressure sensor in order to adjust the concentration of the fuel gas in the fuel off-gas that is circulated to the fuel gas supply passage via the fuel off-gas circulation passage.
- In the fuel cell system according to claim 1, The fuel cell further comprises an ammeter for measuring the output current, The fuel cell system is characterized in that, in addition to controlling according to the pressure measurement value, the control device controls the number of times the exhaust drain valve is opened and closed according to the current measurement value of the ammeter in order to adjust the concentration of the fuel gas in the fuel off-gas.
- In the fuel cell system according to claim 2, The control device is characterized in that it controls the closing time of the exhaust drain valve per control cycle to be shorter as the current measurement value increases.
- In the fuel cell system according to any one of claims 1 to 3, The control device is characterized in that it controls the closing time of the exhaust drain valve per control cycle to be longer as the pressure measurement value increases.
Description
The technology disclosed in this specification relates to a fuel cell system comprising a fuel cell that generates electricity by receiving a fuel gas and an oxidizer gas. Conventionally, a known technology of this type is, for example, the "fuel cell system" described in Patent Document 1 below. This system comprises a fuel cell, a fuel gas supply passage for supplying fuel gas to the fuel cell, an injector provided in the fuel gas supply passage, an ejector provided in the fuel gas supply passage and between the injector and the fuel cell, and a fuel off-gas circulation passage for circulating fuel off-gas discharged from the fuel cell to the ejector. The ejector generates negative pressure using the fuel gas injected from the injector, uses this negative pressure to draw in fuel off-gas from the fuel off-gas circulation passage, mixes the fuel off-gas with the fuel gas, and discharges and supplies it to the fuel cell. Japanese Patent Publication No. 2022-121309 A schematic diagram illustrating a fuel cell system according to one embodiment.A time chart showing the opening and closing operation of an exhaust drain valve according to one embodiment.A time chart showing the opening and closing operation of an exhaust drain valve according to one embodiment.A graph showing the relationship between the hydrogen concentration and hydrogen pressure of hydrogen absorbed into and released from a hydrogen alloy canister, and the canister temperature, according to one embodiment.A flowchart illustrating the details of hydrogen off-gas circulation amount control according to one embodiment.A closing time map showing the relationship between the closing time and the inlet gas pressure and FC current, according to one embodiment. The following describes in detail, with reference to the drawings, one embodiment of a fuel cell system implemented in an electric vehicle. [Regarding the configuration of the fuel cell system] Figure 1 shows a schematic configuration diagram of the fuel cell system 1 according to this embodiment. As shown in Figure 1, the fuel cell system 1 of this embodiment comprises an FC stack 11, a battery 12, and an inverter 13 (or motor). Furthermore, in this embodiment, the fuel cell system 1 has the above-mentioned devices 11 to 13 connected in parallel, resulting in a simple DC-DC converter-less system without a DC-DC converter. Here, a DC-DC converter is a device that converts DC (direct current) to DC (direct current), and is a device that converts the voltage used in the system to DC. This fuel cell system 1 further comprises a hydrogen system 21 and an air system 22. In this embodiment, the fuel gas is hydrogen gas, and the oxidizer gas is air. The FC stack 11 generates electricity by receiving hydrogen gas from the hydrogen system 21 and air from the air system 22. The FC stack 11 corresponds to an example of the "fuel cell" in this disclosed technology. The electricity generated by the FC stack 11 is supplied to the battery 12 and the inverter 13. The battery 12 is connected to the FC stack 11 via first wirings 14a and 14b. The power generated by the FC stack 11 charges the battery 12 via the first wirings 14a and 14b. The battery 12 is connected to the inverter 13 via first wirings 14a and 14b and second wirings 15a and 15b. Second wiring 15a is connected to first wiring 14a. Second wiring 15b is connected to first wiring 14b. The power charged in the battery 12 is supplied to the inverter 13 via first wirings 14a and 14b and second wirings 15a and 15b. The inverter 13 is driven by power supplied from the FC stack 11 and/or the battery 12 via first wirings 14a and 14b and second wirings 15a and 15b. An ammeter 17 is provided on the first wiring 14a, immediately adjacent to the output port of the FC stack 11, for measuring the FC current IFC, which is the "output current" of the FC stack 11. A first wiring harness 14a between the FC stack 11 and the inverter 13 is provided with an FC relay 18 for switching the connection and disconnection of the wiring harness 14a. Similarly, a battery relay 19 is provided with a first wiring harness 14a between the battery 12 and the inverter 13 for switching the connection and disconnection of the wiring harness 14a. The FC relay 18 is positioned in the first wiring harness 14a between the connection point C1 between the first wiring harness 14a and the second wiring harness 15a and the ammeter 17. The battery relay 19 is positioned in the first wiring harness 14a between the connection point C1 between the first wiring harness 14a and the second wiring harness 15a and the battery 12. Here, each relay 18 and 19 is a component that receives an electrical signal from an external source and switches the electrical circuit on/off or on/off, and has a well-known configuration. The hydrogen system 21 is installed on the anode side of the FC stack 11. This hydrogen system 21 includes a hydrogen gas supply passage 31, an exhaust drainage passage 32, a hydrogen off-