JP2023177808A - fuel cell system - Google Patents

Abstract

An object of the present invention is to provide a fuel cell system in which the moisture content of gas can be set to a desired value. [Solution] A fuel cell system in which gas discharged from a tank filled with gas is passed through a device that changes the amount of water in the gas, and is supplied to the gas circulation system of the fuel cell. [Selection diagram] Figure 1

Description

The present disclosure relates to fuel cell systems.

Various studies have been conducted on fuel cells.
For example, in Patent Document 1, a solid polymer type water electrolysis device and a fuel cell are integrated, which operates without providing auxiliary equipment such as a make-up water tank other than a hydrogen gas-liquid separation tank and an oxygen gas-liquid separation tank. A charging/discharging system using a reversible cell is disclosed.

Japanese Patent Application Publication No. 2013-197079

In the conventional technology, there is a risk that the amount of humidification of the circulating gas supplied to the fuel cell may be insufficient.

The present disclosure has been made in view of the above circumstances, and its main purpose is to provide a fuel cell system that can set the moisture content of gas to a desired value.

The present disclosure provides a fuel cell system in which gas discharged from a tank filled with gas is passed through a device that changes the amount of water in the gas, and is supplied to a gas circulation system of a fuel cell.

In the present disclosure, the device may be at least one selected from the group consisting of a water supply device, a water exchanger, a water remover, a water adsorbent, and a gas-liquid separator.

In the present disclosure, the gas may be a fuel gas.

In the present disclosure, the gas circulation system may include at least one of an ejector and a circulation pump.

The present disclosure can provide a fuel cell system that can set the moisture content of gas to a desired value.

FIG. 1 is a schematic configuration diagram showing an example of a fuel cell system of the present disclosure. FIG. 2 is a schematic configuration diagram showing another example of the fuel cell system of the present disclosure. FIG. 3 is a schematic configuration diagram showing another example of the fuel cell system of the present disclosure. FIG. 4 is a schematic configuration diagram showing another example of the fuel cell system of the present disclosure.

Embodiments according to the present disclosure will be described below. Note that matters other than those specifically mentioned in this specification that are necessary for implementing the present disclosure (for example, the general configuration and manufacturing process of a fuel cell system that do not characterize the present disclosure) are It can be understood as a matter of design by a person skilled in the art based on the prior art in the field. The present disclosure can be implemented based on the content disclosed in this specification and the common general knowledge in the field.
Furthermore, the dimensional relationships (length, width, thickness, etc.) in the figures do not reflect the actual dimensional relationships.
In this specification, "~" indicating a numerical range is used to include the numerical values written before and after it as the lower limit and upper limit.
Furthermore, any combination of upper and lower limits in the numerical range can be adopted.

The present disclosure provides a fuel cell system in which gas discharged from a tank filled with gas is passed through a device that changes the amount of water in the gas, and is supplied to a gas circulation system of a fuel cell.

In the present disclosure, gas discharged from a gas-filled tank (gas tank) is passed through a device whose moisture content changes and is supplied to a gas circulation system. Thereby, the moisture content of the gas can be set to a desired value. The desirable value of the moisture content of the gas is not particularly limited, and can be set as appropriate depending on the environment in which the fuel cell is used.
In the present disclosure, equipment is arranged in which the amount of moisture in the gas changes.
The device that changes the amount of moisture in the gas may be at least one type selected from the group consisting of a water supply device, a water exchanger, a moisture remover, a water adsorbent, and a gas-liquid separator.
The arrangement position of the equipment may be upstream or downstream of the gas circulation system.

In the present disclosure, the gas may be an oxidizing gas, a fuel gas, and especially a fuel gas.
The gas for adjusting the moisture content may be the entire amount of gas that has come out of the tank, or may be a part of the gas that is obtained by branching off the gas flow path.

In this disclosure, fuel gas and oxidant gas are collectively referred to as gas. The gas supplied to the anode is a fuel gas, and the gas supplied to the cathode is an oxidant gas. The fuel gas is a gas mainly containing hydrogen, and may be hydrogen. The oxidant gas is a gas containing oxygen, and may be oxygen, air, dry air, or the like.

The gas circulation system may include at least one of an ejector and a circulation pump, and usually further includes a gas circulation flow path, a gas-liquid separator, an exhaust drain valve, etc. Good too. The exhaust drain valve may be arranged downstream of the FC in the circulation flow path.
When the gas circulation system has an ejector and supplies gas to the ejector or upstream of the ejector, an increase in the gas density and an increase in the gas circulation flow rate have the effect of further increasing the amount of gas humidification.

The tank and the gas circulation system may be connected through a gas supply channel.
A first pressure regulating valve that regulates the pressure of gas supplied from the tank may be disposed in the gas supply channel.
The gas supply channel has a second pressure regulating valve downstream of the first pressure regulating valve, branches from downstream of the first pressure regulating valve and upstream of the second pressure regulating valve, and merges downstream of the second pressure regulating valve and upstream of the FC. It may have a first gas branch flow path.
The gas circulation flow path may merge with the gas supply flow path downstream of the gas supply flow path, or may merge with the gas supply flow path via an ejector. The flow path to the FC that merges with the gas supply flow path of the gas circulation flow path may be both a gas circulation flow path and a gas supply flow path.
The gas circulation flow path may have a gas exhaust flow path that branches at an exhaust and drain valve.
The gas exhaust flow path may have a second gas branch flow path that joins the gas supply flow path downstream of the second pressure regulating valve and upstream of the FC.
The device that changes the amount of water in the gas may be placed on the gas supply flow path, may be placed on the first gas branch flow path, or may be placed on the second gas branch flow path. . In the first gas branch flow path, a third pressure regulating valve may be disposed upstream of the water supply device. The second gas branch flow path may have an orifice disposed downstream of the water supply device.

The fuel cell system of the present disclosure may include a control section.
The control unit controls the operations of the first to third pressure regulating valves, circulation pump, exhaust drainage valve, etc. in the fuel cell system. Physically, the control unit includes, for example, a CPU, a ROM that stores control programs and control data processed by the CPU, a RAM that is mainly used as various work areas for control processing, and an input/output interface. and has. These elements are connected to each other via a bus.

A fuel cell (FC) may have only one single cell, or may be a fuel cell stack, which is a laminate in which a plurality of single cells are stacked.
In this disclosure, both single cells and fuel cell stacks may be referred to as fuel cells.
The number of stacked single cells is not particularly limited, and may be, for example, from 2 to several hundreds.

A single cell of a fuel cell includes at least a membrane electrode gas diffusion layer assembly.
The membrane electrode gas diffusion layer assembly includes an anode gas diffusion layer, an anode catalyst layer, an electrolyte membrane, a cathode catalyst layer, and a cathode gas diffusion layer in this order.

The cathode (oxidant electrode) includes a cathode catalyst layer and a cathode side gas diffusion layer.
The anode (fuel electrode) includes an anode catalyst layer and an anode side gas diffusion layer.
The cathode catalyst layer and the anode catalyst layer are collectively referred to as a catalyst layer. Examples of the anode catalyst and cathode catalyst include Pt (platinum) and Ru (ruthenium), and examples of the carrier supporting the catalyst include carbon materials such as carbon.

The cathode side gas diffusion layer and the anode side gas diffusion layer are collectively referred to as a gas diffusion layer.
The gas diffusion layer may be a conductive member or the like having gas permeability.
Examples of the conductive member include carbon porous bodies such as carbon cloth and carbon paper, and metal porous bodies such as metal mesh and foamed metal.

The electrolyte membrane may be a solid polymer electrolyte membrane. Examples of solid polymer electrolyte membranes include fluorine-based electrolyte membranes such as perfluorosulfonic acid thin films containing water, hydrocarbon-based electrolyte membranes, and the like. The electrolyte membrane may be, for example, a Nafion membrane (manufactured by DuPont).

The single cell may be provided with two separators that sandwich both sides of the membrane electrode gas diffusion layer assembly, if necessary. One of the two separators is an anode side separator and the other is a cathode side separator. In this disclosure, the anode side separator and the cathode side separator are collectively referred to as separators.
The separator may have holes constituting a manifold such as supply holes and discharge holes for allowing fluids such as reaction gas and refrigerant to flow in the stacking direction of the unit cells. As the refrigerant, for example, a mixed solution of ethylene glycol and water can be used to prevent freezing at low temperatures.
Examples of the supply hole include a fuel gas supply hole, an oxidant gas supply hole, a refrigerant supply hole, and the like.
Examples of the exhaust hole include a fuel gas exhaust hole, an oxidant gas exhaust hole, and a refrigerant exhaust hole.
The separator may have a reactive gas flow path on the surface in contact with the gas diffusion layer. Further, the separator may have a coolant flow path for keeping the temperature of the fuel cell constant on the surface opposite to the surface in contact with the gas diffusion layer.
The separator may be a gas-impermeable conductive member or the like. The conductive member may be, for example, dense carbon made gas impermeable by compressing carbon, or a press-formed metal (eg, iron, aluminum, stainless steel, etc.) plate. Further, the separator may have a current collecting function.

FIG. 1 is a schematic configuration diagram showing an example of a fuel cell system of the present disclosure.
Specifically, FIG. 1 is a schematic configuration diagram showing an example of the fuel cell system of the present disclosure, in order from the top: (1) a gas circulation system includes a circulation pump, and the amount of water in the gas changes; When a water supply device is provided upstream of the gas circulation system as a device, (2) a circulation pump is provided as the gas circulation system, and a water exchanger is provided upstream of the gas circulation system as a device that changes the amount of water in the gas. (3) A case is shown in which a circulation pump is provided as a gas circulation system, and a water adsorbent is provided upstream of the gas circulation system as a device that changes the amount of water in the gas.
In Figure 1, (1) to (3) in common, the gas circulation system is provided with a circulation pump, a gas-liquid separator, and an exhaust drain valve, and the gas coming out of the tank is branched from the upstream of the gas circulation system. A portion of the gas whose flow rate is controlled by the pressure regulating valve passes through a device that changes the amount of water in the gas, thereby changing the amount of water in the gas.
In the case of the water exchanger (2), the water exchanger may recover moisture contained in the gas discharged from the exhaust and drain valve, and supply the moisture to the gas passing upstream of the gas circulation system.
In the case of water adsorbent (3), a separate system is prepared to supply moisture to the water adsorbent, the water supplied from the separate system is adsorbed to the water adsorbent, and the water adsorbed by the water adsorbent is circulated through gas circulation. It may also be fed to the gas passing upstream of the system.
The tank and the gas circulation passage of the gas circulation system are connected by a gas supply passage.
A first pressure regulating valve that regulates the pressure of gas supplied from the tank is arranged in the gas supply flow path.
The gas supply channel has a second pressure regulating valve downstream of the first pressure regulating valve adjacent to the tank, branches from downstream of the first pressure regulating valve and upstream of the second pressure regulating valve, and branches downstream of the second pressure regulating valve and FC. It has a first gas branch flow path that joins upstream of the gas flow path.
The gas circulation flow path has a gas exhaust flow path that branches at an exhaust and drain valve.
The gas supplied from the tank in FIG. 1 may be an oxidant gas or a fuel gas.
Although FIG. 1 only shows a system for one of the fuel gas and oxidant gas for convenience, the fuel cell system of the present disclosure usually also has a system for the other gas, and is further cooled. It may have a system.
That is, the fuel cell system of the present disclosure may include a fuel gas system, an oxidant gas system, and a cooling system. The fuel gas system supplies fuel gas to the anode of the fuel cell, the oxidizing gas system supplies oxidizing gas to the cathode of the fuel cell, and the cooling system supplies refrigerant to the fuel cell to control the temperature of the fuel cell. Adjust.

FIG. 2 is a schematic configuration diagram showing another example of the fuel cell system of the present disclosure.
Specifically, FIG. 2 is a schematic configuration diagram showing an example of the fuel cell system of the present disclosure, in order from the top: (4) equipment that has an ejector as a gas circulation system and changes the amount of water in the gas; (5) When the gas circulation system includes an ejector and a water exchanger is installed upstream from the gas circulation system as a device that changes the amount of water in the gas. , (6) A case is shown in which an ejector is provided as a gas circulation system, and a water adsorbent is provided upstream of the gas circulation system as a device in which the amount of water in the gas changes.
The ejector has a nozzle on the gas inlet side and a diffuser on the gas outlet side.
In FIG. 2, the configuration is the same as that in FIG. 1 except that the gas circulation system includes an ejector instead of a circulation pump.

FIG. 3 is a schematic configuration diagram showing another example of the fuel cell system of the present disclosure.
Specifically, FIG. 3 is a schematic configuration diagram showing an example of the fuel cell system of the present disclosure, in order from the top: (7) equipment that has an ejector as a gas circulation system and changes the amount of water in the gas; (8) When a water supply device is provided upstream of the gas circulation system, and the entire amount of gas coming out of the tank passes through a device that changes the amount of moisture in the gas, (8) The gas circulation system includes an ejector, and This example shows a case in which a water supply device is provided upstream of the gas circulation system as a device in which the amount of moisture changes, and a portion of the gas discharged from the tank passes through the device in which the amount of moisture in the gas changes.
In FIG. 3, (7) is the same configuration as the configuration in FIG. 2 except that the entire amount of gas coming out of the tank passes through a device that changes the amount of moisture in the gas, and (8) is the same as the configuration in FIG. This is the same configuration as (4) in FIG.

FIG. 4 is a schematic configuration diagram showing another example of the fuel cell system of the present disclosure.
Specifically, FIG. 4 is a schematic configuration diagram showing an example of the fuel cell system of the present disclosure, in order from the top: (9) equipment having an ejector as a gas circulation system and changing the amount of water in the gas; (10) When the gas circulation system is equipped with a water supply device and the gas that has branched from the tank and passed through the water supply device joins upstream of the ejector of the gas circulation system, When a water supply device is provided as a device whose amount changes, and the gas that has branched from the tank and passed through the water supply device joins downstream of the ejector of the gas circulation system, (11) the gas circulation system includes the ejector and the gas-liquid A water supply device is provided as a device that has a separator and changes the amount of water in the gas. This shows the case where they pass through an orifice upstream of the ejector and merge.
In FIG. 4, the exhaust and drain valves are omitted for convenience. In FIG. 4, the configuration other than the above is the same as the configuration in FIG. 2 (4).
In (10), the gas supply flow path has a second pressure regulating valve downstream of the first pressure regulating valve adjacent to the tank, branches from downstream of the first pressure regulating valve and upstream of the second pressure regulating valve, and has a second pressure regulating valve adjacent to the tank. It has a first gas branch flow path that joins downstream of the pressure valve, downstream of the ejector, and upstream of the FC, a water supply device is disposed on the first gas branch flow path, and a third pressure regulating valve is arranged upstream of the water supply device. There is.
In (11), the gas exhaust flow path has a second gas branch flow path that joins the gas supply flow path downstream of the second pressure regulating valve and upstream of the ejector, and has a water supply device on the second gas branch flow path. , an orifice is located downstream of the water supply.

Claims (4)

A fuel cell system that passes gas from a tank filled with gas through a device that changes the amount of moisture in the gas and supplies it to the gas circulation system of the fuel cell. The fuel cell system according to claim 1, wherein the device is at least one selected from the group consisting of a water supply device, a water exchanger, a water remover, a water adsorbent, and a gas-liquid separator. The fuel cell system according to claim 1, wherein the gas is a fuel gas. The fuel cell system according to claim 1, wherein the gas circulation system includes at least one of an ejector and a circulation pump.