JP-7857332-B2 - Fuel cell system

JP7857332B2JP 7857332 B2JP7857332 B2JP 7857332B2JP-7857332-B2

Inventors

石川一紗
竹越聖也

Assignees

本田技研工業株式会社

Dates

Publication Date: 20260512
Application Date: 20240319

Claims (6)

A fuel cell stack that generates electricity using the anode gas in the anode channel and the cathode gas in the cathode channel, an anode supply channel for supplying the anode gas to the anode channel, A cathode supply channel for supplying the cathode gas to the cathode channel, An anode discharge channel through which the anode discharge fluid discharged from the anode channel flows, A cathode discharge channel through which the cathode discharge fluid discharged from the cathode channel flows, A fluid confluence section that combines the anode discharge fluid that has flowed through the anode discharge channel and the cathode discharge fluid that has flowed through the cathode discharge channel, A discharge pipe that guides the combined fluids that merged at the aforementioned fluid confluence to the outside, an anode discharge valve that controls the flow of the anode discharge fluid toward the fluid confluence, A fuel cell system comprising a control unit that controls the opening and closing of the anode discharge valve, The control unit, The hydrogen concentration of the aforementioned combined fluid is obtained, When the amount of power generated by the fuel cell stack is below a predetermined power generation threshold, the anode discharge valve is controlled to repeatedly open and close for a predetermined opening time determined so that the hydrogen concentration does not reach a predetermined specified value . A fuel cell system characterized by the following features.
In the fuel cell system according to claim 1, The control unit, The hydrogen concentration of the anode discharge fluid is further obtained, and when the hydrogen concentration of the anode discharge fluid is below a predetermined concentration threshold and the amount of power generated by the fuel cell stack is below the power generation threshold, the opening and closing operation of the anode discharge valve is controlled so as to repeat the opening operation, which is performed by opening for a certain opening time based on the hydrogen concentration of the combined fluid and closing for a shorter closing time than the opening time. A fuel cell system characterized by the following features.
In the fuel cell system according to claim 1, The control unit, The hydrogen concentration of the anode discharge fluid is further obtained, and if the hydrogen concentration of the anode discharge fluid is below a predetermined concentration threshold and the amount of power generated by the fuel cell stack exceeds the power generation threshold, the anode discharge valve is opened. A fuel cell system characterized by the following features.
In the fuel cell system according to any one of claims 1 to 3, The control unit, The hydrogen concentration at the outlet of the discharge pipe is obtained as the hydrogen concentration of the combined fluid, and the flow velocity of the combined fluid at the outlet of the discharge pipe is further obtained. The opening time of the anode discharge valve is determined based on the flow velocity and hydrogen concentration at the outlet. A fuel cell system characterized by the following features.
In the fuel cell system according to any one of claims 1 to 3, The control unit, The hydrogen concentration of the combined fluid at the outlet of the discharge pipe is obtained. The opening time of the anode discharge valve is determined based on the shape of the discharge pipe and the hydrogen concentration at the outlet. A fuel cell system characterized by the following features.
In the fuel cell system according to any one of claims 1 to 3, The control unit, The hydrogen concentration of the combined fluid at the outlet of the discharge pipe is obtained. The opening time is determined to be shorter than the time it takes for the hydrogen concentration at the outlet to rise to the specified value after the anode discharge valve is opened. A fuel cell system characterized by the following features.

Description

This invention relates to a fuel cell system. In fuel cell systems, when the anode off gas, which contains hydrogen, nitrogen, and water, is discharged to the outside (into the atmosphere), the gas to be discharged is diluted using air (nitrogen, oxygen, etc.) drawn in from the outside. Therefore, if a large amount of air is required for dilution, the power consumption of the air supply compressor and other equipment increases. To address this, systems have been proposed that achieve both improved fuel efficiency and maintenance of hydrogen concentration (see Patent Document 1). Japanese Patent Publication No. 2023-132388 A schematic diagram of a fuel cell system according to an embodiment of the present invention.A schematic diagram showing the relationship between valve opening and closing timing and hydrogen concentration in the combined gas.A flowchart illustrating an example of valve control processing performed by the control unit based on a program. Embodiments of the invention will be described below with reference to the drawings. <Fuel cell system configuration> Figure 1 is a schematic diagram of the fuel cell system 10 according to the present invention. The fuel cell system 10 is mounted on a vehicle (fuel cell vehicle). Separately, the fuel cell system 10 can also be mounted on, for example, ships, aircraft, robots, etc. The fuel cell system 10 includes a fuel cell stack 12, a hydrogen tank 14, an anode system 16, a cathode system 18, and a cooling system 20. The fuel cell system 10 also includes a control device 94. The output (power) of the fuel cell stack 12 is supplied to a load (not shown) such as a motor. The fuel cell stack 12 has multiple power generation cells 22 stacked in one direction. Each power generation cell 22 has an electrolyte membrane/electrode structure 24 (also simply called the electrode structure 24) and a pair of separators 26, 28. The pair of separators 26, 28 sandwich the electrode structure 24. The electrode structure 24 comprises a solid polymer electrolyte membrane 30 (also simply called the electrolyte membrane 30), an anode electrode 32, and a cathode electrode 34. The electrolyte membrane 30 is, for example, a thin film of perfluorosulfonic acid containing water. The anode electrode 32 and the cathode electrode 34 sandwich the electrolyte membrane 30. The anode electrode 32 and the cathode electrode 34 have a gas diffusion layer made of carbon paper or the like. An electrode catalyst layer is formed by uniformly coating the surface of the gas diffusion layer with porous carbon particles. A platinum alloy is supported on the surface of the porous carbon particles. The electrode catalyst layer is formed on both sides of the electrolyte membrane 30. On the surface of the separator 26 facing the electrode structure 24, an anode channel 36 is formed. The anode channel 36 is connected to the anode supply channel 40 via the anode inlet 17A. The anode channel 36 is connected to the anode discharge channel 42 via the first anode outlet 17B. Furthermore, the anode channel 36 is connected to the second drain channel 48 via the second anode outlet 17C. The second anode outlet 17C is located lower than the first anode outlet 17B. On the surface of the separator 28 facing the electrode structure 24, a cathode channel 38 is formed. The cathode channel 38 is connected to the cathode supply channel 62 via the cathode inlet 19A. The cathode channel 38 is connected to the cathode discharge channel 64 via the cathode outlet 19B. Anode gas (hydrogen) is supplied to the anode electrode 32. At the anode electrode 32, hydrogen ions and electrons are generated from hydrogen molecules through a catalytic electrode reaction. The hydrogen ions permeate the electrolyte membrane 30 and move to the cathode electrode 34. The electrons move in the following order: the negative electrode terminal (not shown) of the fuel cell stack 12, the load such as a motor, the positive electrode terminal (not shown) of the fuel cell stack 12, and finally to the cathode electrode 34. At the cathode electrode 34, water is produced by the reaction of hydrogen ions and electrons with oxygen contained in the supplied air, due to the action of the catalyst. The anode system 16 has components for supplying anode gas to the anode electrode 32 and components for discharging anode off-gas from the anode electrode 32. The anode system 16 has an anode supply channel 40, an anode discharge channel 42, a circulation channel 44, a first drain channel 46, and a second drain channel 48. The anode system 16 also has an injector 50, an ejector 52, a gas-liquid separator 54, a first drain valve 56, and a second drain valve 58. The anode discharge channel 42, the first drain channel 46, and the second drain channel 48 are sometimes collectively referred to as the anode discharge channel. Furthermore, the first drain valve 56 and the second drain valve 58 are sometimes collectively referred to as the drain valve. The anode supply