JP2021009832A - Fuel cell system - Google Patents

Abstract

To make it possible, in the case that produced water can be frozen even when scavenging processing is performed, to notify a user of the situation.SOLUTION: When scavenging determination means determines that scavenging processing on a fuel cell by scavenging means is possible and freezing determination means determines on the basis of a first determination threshold that produced water of the fuel cell may be frozen, the scavenging means performs the scavenging processing and notification means notifies a user of a freezing determination result. When the scavenging determination means determines that the scavenging processing on the fuel cell by the scavenging means is impossible and the freezing determination means determines on the basis of a second determination threshold laxer than the first determination threshold that produced water of the fuel cell may be frozen, the scavenging means does not perform the scavenging processing and the notification means notifies a user of a freezing determination result. When the freezing determination means determines that produced water of the fuel cell may not be frozen, the notification means does not notify a user of a freezing determination result.SELECTED DRAWING: Figure 2

Description

The present invention relates to a fuel cell system.

A fuel cell system is known in which a scavenging means is driven by the electric power of a storage means to scaveng the generated water in the fuel cell (see, for example, Patent Document 1).

Japanese Unexamined Patent Publication No. 2010-108757

However, in the above fuel cell system, for example, when the amount of generated water is large, the generated water in the fuel cell may remain and freeze even if the scavenging treatment is executed. In that case, user support may be required.

The present invention has been made to solve such a problem, and provides a fuel cell system capable of notifying a user when the generated water may freeze even after scavenging treatment. The main purpose is that.

One aspect of the present invention for achieving the above object is
With a fuel cell
A scavenging means for scavenging the generated water of the fuel cell and
A scavenging determination means for determining whether or not scavenging processing by the scavenging means is possible based on the electricity storage state of the storage means for supplying electric power to the scavenging means while the power generation of the fuel cell is stopped.
A freezing determination means for determining whether or not the generated water freezes while the power generation of the fuel cell is stopped.
When the generated water is determined to be frozen by the freezing determination means, a notification means for notifying the user of the freeze determination result, and
It is a fuel cell system equipped with
When the scavenging determination means determines that the scavenging process by the scavenging means is possible, and the freeze determination means determines that the generated water freezes based on the first determination threshold value, the scavenging means determines that the generated water freezes. The processing is performed, and the notification means notifies the user of the freeze determination result.
The scavenging determination means determines that the scavenging process by the scavenging means is impossible, and the freeze determination means determines that the generated water freezes based on a second determination threshold that is looser than the first determination threshold. In this case, the scavenging means does not perform the scavenging process, and the notification means notifies the user of the freeze determination result.
When the freezing determination means determines that the generated water does not freeze, the notification means does not notify the user of the freeze determination result.
It is a fuel cell system.

According to the present invention, it is possible to provide a fuel cell system capable of notifying the user when the generated water may freeze even after the scavenging treatment.

It is a block diagram which shows the schematic system configuration of the fuel cell system which concerns on one Embodiment of this invention. It is a block diagram which shows the schematic system configuration of the control device which concerns on one Embodiment of this invention. It is a flowchart which shows the flow of the control process of the fuel cell system which concerns on one Embodiment of this invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. The fuel cell system according to the embodiment of the present invention is mounted on, for example, a fuel cell vehicle equipped with a fuel cell as an in-vehicle power source. FIG. 1 is a block diagram showing a schematic system configuration of the fuel cell system according to the present embodiment.

The fuel cell system 10 according to the first embodiment notifies the fuel cell 1, the secondary battery 2, the oxide gas flow path system 3, the fuel gas flow path system 4, the temperature sensor 5, the control device 6, and the like. It is provided with a part 7.

The fuel cell 1 is formed with a membrane electrode structure in which a solid polymer electrolyte membrane is sandwiched between an anode electrode and a cathode electrode from both sides. A pair of separators are arranged on both sides of the film electrode structure, and a flat plate-shaped unit fuel cell 11 (hereinafter, referred to as a unit cell 11) is formed. The fuel cell 1 has a stack structure in which a plurality of the unit cells 11 are stacked.

In the fuel cell 1, hydrogen gas is supplied as an anode gas (fuel gas) between the anode electrode and the separator, and air is supplied as the cathode gas (oxidizing gas) between the cathode electrode and the separator. As a result, hydrogen ions generated by the catalytic reaction at the anode electrode permeate through the solid polymer electrolyte membrane and move to the cathode electrode, causing an electrochemical reaction with oxygen in the air at the cathode electrode to generate power. Along with this power generation, water (hereinafter referred to as generated water) is generated inside the fuel cell 1. The electric power generated by the fuel cell 1 is stored in the secondary battery 2 via the DC / DC converter 8.

The fuel cell 1 and the secondary battery 2 can supply electric power to the air compressor 32, the circulation pump 48, and various valves, which will be described later. The secondary battery 2 is a specific example of the power storage means. The secondary battery 2 is, for example, a lithium ion battery. The secondary battery 2 may be composed of a nickel hydrogen battery or the like.

The oxidation gas flow path system 3 includes an oxidation gas pipe 31, an air compressor 32, an oxidation gas on-off valve 33, a cathode off gas pipe 34, and a regulator 35. The oxidation gas flow path system 3 includes a flow path on the cathode side in the fuel cell 1.

The air compressor 32 is connected to the fuel cell 1 via an oxidation gas pipe 31. The air compressor 32 and the circulation pump 48 described later are specific examples of the scavenging means. The air compressor 32 compresses the air taken in from the outside in response to the control signal from the control device 6 and supplies it to the fuel cell 1 as an oxidation gas.

The oxidation gas on-off valve 33 is provided between the air compressor 32 and the fuel cell 1. The oxidation gas on-off valve 33 opens and closes according to the flow of the supply air in the oxidation gas pipe 31. Specifically, the oxide gas on-off valve 33 is normally in a closed state, and is opened when air having a predetermined pressure is supplied from the air compressor 32 to the oxidation gas pipe 31.

The cathode off gas pipe 34 discharges the cathode off gas discharged from the cathode of the fuel cell 1 to the outside of the fuel cell system 10. The regulator 35 adjusts the pressure of the cathode off gas (back pressure on the cathode side of the fuel cell 1) in the cathode off gas pipe 34 in response to the control signal from the control device 6.

The fuel gas flow path system 4 includes a fuel gas pipe 40, a hydrogen tank 41, a fuel gas on-off valve 42, a regulator 43, an injector 44, an exhaust / drain valve 45, an anode off-gas pipe 46, and a circulation pipe 47. , A circulation pump 48, and a gas-liquid separator 49.

The fuel gas flow path system 4 includes a flow path on the anode side in the fuel cell 1. In the following, the fuel gas pipe 40 is composed of a downstream side of the injector 44, a flow path on the anode side in the fuel cell 1, an anode off-gas pipe 46, a circulation pipe 47, and a gas-liquid separator 49. The flow path is referred to as a circulation flow path 9. The circulation flow path 9 is a flow path for circulating the anode off gas of the fuel cell 1 to the fuel cell 1.

The hydrogen tank 41 is connected to the anode of the fuel cell 1 via the fuel gas pipe 40, and supplies the hydrogen filled therein to the fuel cell 1. The fuel gas on-off valve 42, the regulator 43, and the injector 44 are provided in the fuel gas pipe 40 from the upstream side, that is, the side close to the hydrogen tank 41 in this order.

The fuel gas on-off valve 42 opens and closes in response to a control signal from the control device 6 to control the inflow of hydrogen from the hydrogen tank 41 to the upstream side of the injector 44. When the fuel cell system 10 is stopped, the fuel gas on-off valve 42 is closed. The regulator 43 adjusts the hydrogen pressure on the upstream side of the injector 44 in response to the control signal from the control device 6.

The injector 44 is an electromagnetically driven on-off valve in which the valve body is electromagnetically driven according to the drive cycle and valve opening time set by the control device 6. The control device 6 controls the amount of hydrogen supplied to the fuel cell 1 by controlling the drive cycle and valve opening time of the injector 44.

The anode off-gas pipe 46 is a pipe that connects the outlet of the anode of the fuel cell 1 and the gas-liquid separator 49. The anode off-gas pipe 46 guides the anode-off gas containing fuel gas, nitrogen gas, etc., which has not been used in the power generation reaction, to the gas-liquid separator 49.

The gas-liquid separator 49 is connected between the anode off-gas pipe 46 and the circulation pipe 47 of the circulation flow path 9. The gas-liquid separator 49 separates the generated water from the anode off gas in the circulation flow path 9 and stores it.

The circulation pipe 47 is connected downstream from the injector 44 of the fuel gas pipe 40. The circulation pipe 47 is provided with a circulation pump 48 that is driven in response to a control signal from the control device 6. The circulation pump 48 sends the anode-off gas from which the generated water is separated by the gas-liquid separator 49 to the fuel gas pipe 40. As described above, in the fuel cell system 10, the anode off gas containing hydrogen is circulated and supplied to the fuel cell 1 again to improve the efficiency of hydrogen utilization.

The exhaust / drain valve 45 is provided at the lower part of the gas-liquid separator 49. The exhaust / drain valve 45 drains the generated water stored in the gas-liquid separator 49 and exhausts the anode off gas in the gas-liquid separator 49. During the operation of the fuel cell system 10, the exhaust / drain valve 45 is normally closed and opens / closes in response to a control signal from the control device 6. In the present embodiment, the exhaust drain valve 45 is connected to the cathode off gas pipe 34, and the generated water and the anode off gas discharged by the exhaust drain valve 45 are discharged to the outside through the cathode off gas pipe 34.

The temperature sensor 5 is provided in, for example, the fuel cell 1 and detects the temperature inside the fuel cell 1. The temperature sensor 5 may be provided in the oxidation gas flow path system 3 or the fuel gas flow path system 4. The temperature sensor 5 transmits the detected temperature in the fuel cell 1 to the control device 6.

By the way, the generated water generated during the operation of the fuel cell system 10 may remain inside the fuel cell 1. When the temperature of the fuel cell 1 drops below the freezing point after the operation of the fuel cell 1 is completed, the generated water remaining inside the fuel cell 1, for example, in the pores of the catalyst layer or the gas diffusion layer in the single cell freezes. As a result, the flow of reaction gas and off-gas at the next start is hindered.

On the other hand, the control device 6 according to the present embodiment controls the air compressor 32, the fuel gas on-off valve 42, the exhaust drain valve 45, the circulation pump 48, and the like while the power generation of the fuel cell 1 is suspended, and the fuel cell. A scavenging process is performed to sweep the generated water in 1. In this scavenging process, at the same time as the generated water in the fuel cell 1, the generated water remaining in each pipe and each valve adjacent to the fuel cell 1 is also scavenged.

The control device 6 includes, for example, a CPU (Central Processing Unit) 6a that performs control processing, arithmetic processing, and the like, a ROM (Read Only Memory) and a RAM (Random Access Memory) that store a control program, an arithmetic program, and the like executed by the CPU 6a. ), And an interface unit (I / F) 6c that inputs and outputs signals to and from the outside, etc., and the hardware is configured around the microcomputer. The CPU 6a, the memory 6b, and the interface unit 6c are connected to each other via a data bus or the like.

FIG. 2 is a block diagram showing a schematic system configuration of the control device according to the present embodiment. The control device 6 according to the present embodiment includes a control unit 61 that performs control processing, an SOC detection unit 62 that detects the amount of stored electricity, and a freeze determination unit that determines whether or not the generated water in the fuel cell 1 freezes. It has 63 and a scavenging determination unit 64 for determining whether or not the scavenging process described above is possible.

As described above, the control unit 61 controls the air compressor 32, the regulator 35, the fuel gas on-off valve 42, the regulator 43, the injector 44, the exhaust drain valve 45, the circulation pump 48, and the like to control the power generation by the fuel cell 1. To execute. Further, the control unit 61 controls the air compressor 32 and the like to execute the scavenging process while the power generation of the fuel cell system 10 is stopped. The scavenging process in this embodiment is performed while the power generation of the fuel cell system 10 is stopped. Therefore, power is supplied from the secondary battery 2 to the control unit 61, the air compressor 32, and the like.

The SOC detection unit 62 is connected to the secondary battery 2. The SOC detection unit 62 detects the stored amount (SOC: State Of Charge) [%] of the secondary battery 2 and transmits it to the scavenging determination unit 64. The amount of electricity stored refers to, for example, the ratio of the remaining charge to the current charge capacity of the secondary battery 2. The SOC detection unit 62 detects the temperature of the secondary battery 2, the output voltage value, and the output current value, and detects the amount of electricity stored based on these detected values.

The freeze determination unit 63 may freeze the generated water in the fuel cell 1 while the power generation of the fuel cell 1 is stopped, based on the temperature in the fuel cell 1 from the temperature sensor 5 and the weather information. Judge whether or not. Meteorological information includes information that predicts changes in temperature, humidity, weather, and the like. The freezing determination unit 63 is a specific example of the freezing determination means. The freezing determination unit 63 estimates the temperature change of the generated water in the fuel cell 1, and when it is determined that the estimated temperature of the generated water (average value, etc.) is equal to or less than the determination threshold value, the generated water in the fuel cell 1 is frozen. Then, it may be determined.

Further, the freeze determination unit 63 determines whether or not the generated water in the fuel cell 1 freezes after a predetermined time based on the temperature, weather information, GPS (Global Positioning System) information, atmospheric pressure information, and the like in the fuel cell 1. May be determined with higher accuracy.

The freeze determination unit 63 can acquire weather information via the Internet or the like. The freezing determination unit 63 can acquire atmospheric pressure information from the atmospheric pressure sensor of the vehicle. The GPS information includes position information in which the vehicle equipped with the fuel cell system 10 is stopped. For example, when it is determined that a vehicle is parked at home or at work based on GPS information, it is assumed that the vehicle will stop at that position for a long time. Further, for example, when it is determined that a vehicle is stopped at a hydrogen station or a convenience store based on GPS information, it is assumed that the vehicle will move immediately from that position. When the freeze determination unit 63 receives the off signal from the ignition switch, it determines that the power generation of the fuel cell 1 is stopped. The freeze determination unit 63 transmits the above-mentioned freeze determination result to the notification unit 7.

The scavenging determination unit 64 determines whether or not the scavenging process by the above-mentioned air compressor 32 or the like is possible. The scavenging determination unit 64 is a specific example of the scavenging determination means. The scavenging determination unit 64 determines whether or not the scavenging process by the above-mentioned air compressor 32 or the like is possible based on the electricity storage state of the secondary battery 2 while the power generation of the fuel cell 1 is stopped.

When the amount of electricity stored in the secondary battery 2 from the SOC detection unit 62 is less than or equal to a predetermined amount, the scavenging determination unit 64 may determine that the scavenging process by the above-mentioned air compressor 32 or the like is impossible. For example, in the memory 6b or the like, the amount of electricity stored so that the air compressor 32 and the circulation pump 48 cannot be driven is set as the predetermined amount. When the scavenging determination unit 64 determines that the secondary battery 2 is out of order based on the amount of change in the amount of electricity stored in the secondary battery 2 from the SOC detection unit 62, the scavenging process by the above-mentioned air compressor 32 or the like is not performed. It may be determined that it is possible.

When the freeze determination unit 63 determines that the generated water in the fuel cell 1 is frozen, the notification unit 7 notifies a user such as a driver of the freeze determination result. The notification unit 7 may display, for example, a display unit such as an instrument panel of a vehicle, a multi-display, or a user's smartphone indicating that the generated water of the fuel cell 1 is frozen. The notification unit 7 may notify the user that the fuel cell 1 is likely to freeze by sounding a warning sound from a speaker or the like.

The notification unit 7 may notify the user of the corresponding action together with the above-mentioned freeze determination result. For example, in order to prevent the fuel cell 1 from freezing, the notification unit 7 gives an "instruction to store the vehicle in the garage", an "instruction to cover the entire vehicle or one part of the fuel cell", and an "instruction to install a heater". , "Instruction to move to a sunny place" may be notified.

By the way, for example, when the amount of generated water is large or the temperature is particularly low, the produced water may freeze even if the above-mentioned scavenging treatment is performed. In that case, it may be necessary for the user to take appropriate measures such as storing the vehicle in the garage.

On the other hand, in the present embodiment, the scavenging determination unit 64 determines that the scavenging process by the air compressor 32 is possible, and the freezing determination unit 63 generates water in the fuel cell 1 based on the first determination threshold value. When it is determined to freeze, the control unit 61 executes a scavenging process such as the air compressor 32, and the notification unit 7 notifies the user of the determination result of freezing.

As a result, when there is a possibility that the generated water in the fuel cell 1 freezes even if the scavenging process is performed, the user can be notified of the result of the freeze determination, and the user can take countermeasures against the freeze. It can be carried out. For example, the user receives a determination result from the notification unit 7 that the vehicle is frozen, stores the vehicle in the garage, covers the entire vehicle or one part of the fuel cell, installs a heater, and puts the vehicle in a sunny place. Corresponding measures such as moving can be taken. For example, after performing the scavenging treatment, the temperature at which the generated water in the fuel cell 1 is predicted to freeze is experimentally obtained, and is set in the memory 6b as the first determination threshold value.

Further, the scavenging determination unit 64 determines that the scavenging process by the air compressor 32 is impossible, and the freezing determination unit 63 determines that the generated water in the fuel cell 1 is based on the second determination threshold value that is looser than the first determination threshold value. When it is determined that the air is frozen, the control unit 61 does not execute the scavenging process of the air compressor 32, and the notification unit 7 notifies the user of the determination result of freezing.

As a result, when there is a possibility that the generated water in the fuel cell 1 freezes without performing the scavenging process, the user can be notified of the freeze determination result, and the user responds to the freeze as described above. Actions can be taken.

Since the first determination threshold is a threshold for determining whether the generated water is still frozen even after the above-mentioned scavenging treatment is performed, it is determined whether or not the generated water is frozen without performing the above-mentioned scavenging treatment. A stricter value (lower value) is set than the second determination threshold value for performing.

In this way, if the scavenging process can be performed, the user is notified based on the expected freezing possibility, which is lower than the case where the scavenging process cannot be performed. This allows the user to recognize that the produced water can freeze only when it is really needed. Therefore, for example, it becomes easy to notify the user of a countermeasure such as parking the vehicle in a place where it is difficult to freeze.

Further, when the freezing determination unit 63 determines that the generated water in the fuel cell 1 does not freeze, the notification unit 7 determines that the water is frozen regardless of whether the scavenging process of the air compressor 32 or the like is executed or not executed. Do not notify the user of the result. In this case, since there is a high possibility that the generated water in the fuel cell 1 will not freeze, the notification unit 7 does not need to notify the user of the freeze determination result as described above.

FIG. 3 is a flowchart showing a flow of control processing of the fuel cell system according to the present embodiment. The scavenging determination unit 64 determines whether or not the power generation of the fuel cell 1 is stopped (step S101). When the scavenging determination unit 64 determines that the power generation of the fuel cell 1 is stopped (YES in step S101), whether or not the scavenging process by the above-mentioned air compressor 32 or the like is possible based on the electricity storage state of the secondary battery 2. (Step S102).

When the scavenging determination unit 64 determines that the scavenging process by the air compressor 32 or the like is possible (YES in step S102), the freeze determination unit 63 freezes the generated water in the fuel cell 1 based on the first determination threshold value. Whether or not it is determined (step S103).

When the freezing determination unit 63 determines that the generated water in the fuel cell 1 freezes (YES in step S103), the control unit 61 controls the air compressor 32 and the like to execute the scavenging process (step S104), which will be described later. (Step S106). On the other hand, when the freezing determination unit 63 determines that the generated water in the fuel cell 1 does not freeze (NO in step S103), this process ends.

When the scavenging determination unit 64 determines that the scavenging process by the air compressor 32 is impossible (NO in step S102), the freeze determination unit 63 freezes the generated water in the fuel cell 1 based on the second determination threshold value. Whether or not it is determined (step S105).

When the freezing determination unit 63 determines that the generated water in the fuel cell 1 is frozen (YES in step S105), the process proceeds to the process described later (step S106). On the other hand, when the freezing determination unit 63 determines that the generated water in the fuel cell 1 does not freeze (NO in step S105), this process ends.
The notification unit 7 notifies the response action together with the freeze determination result (step S106).

Although some embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other embodiments, and various omissions, replacements, and changes can be made without departing from the gist of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are also included in the scope of the invention described in the claims and the equivalent scope thereof.

1 Fuel cell, 2 Secondary battery, 3 Oxidation gas flow path system, 4 Fuel gas flow path system, 5 Temperature sensor, 6 Control device, 7 Notification unit, 8 DC / DC converter, 9 Circulation flow path, 10 Fuel cell system , 31 Oxidized gas piping, 32 Air pump, 33 Oxidized gas on-off valve, 34 Cathode-off gas piping, 35 Regulator, 40 Fuel gas piping, 41 Hydrogen tank, 42 Fuel gas on-off valve, 43 Regulator, 44 Injector, 45 Exhaust drain valve, 46 Anodic off-gas piping, 47 Circulation piping, 48 Circulation pump, 49 Gas-liquid separator, 61 Control unit, 62 SOC detection unit, 63 Freezing determination unit, 64 Sweep determination unit

Claims (1)

With a fuel cell
A scavenging means for scavenging the generated water of the fuel cell and
A scavenging determination means for determining whether or not scavenging processing by the scavenging means is possible based on the electricity storage state of the storage means for supplying electric power to the scavenging means while the power generation of the fuel cell is stopped.
A freezing determination means for determining whether or not the generated water freezes while the power generation of the fuel cell is stopped.
When the generated water is determined to be frozen by the freezing determination means, a notification means for notifying the user of the freeze determination result, and
It is a fuel cell system equipped with
When the scavenging determination means determines that the scavenging process by the scavenging means is possible, and the freeze determination means determines that the generated water freezes based on the first determination threshold value, the scavenging means determines that the generated water freezes. The processing is performed, and the notification means notifies the user of the freeze determination result.
The scavenging determination means determines that the scavenging process by the scavenging means is impossible, and the freeze determination means determines that the generated water freezes based on a second determination threshold that is looser than the first determination threshold. In this case, the scavenging means does not perform the scavenging process, and the notification means notifies the user of the freeze determination result.
When the freezing determination means determines that the generated water does not freeze, the notification means does not notify the user of the freeze determination result.
Fuel cell system.

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