US-12626940-B2 - Fuel cell system

Abstract

A fuel cell system includes a first battery, a second battery having a second battery voltage larger than the first battery voltage, and a step-down device for stepping down a voltage of the second battery. When the voltage supplied from the first battery to the control device is equal to or lower than the voltage threshold value, the control device supplies electric power to the bypass valve from the step-down device to perform opening degree learning for the bypass valve.

Inventors

• Sho AKABORI
• Shuto MANIWA
• Tomoyuki Inoue

Assignees

• HONDA MOTOR CO., LTD.

Dates

Publication Date

20260512

Application Date

20230328

Priority Date

20220330

Claims (3)

1. 1 . A fuel cell system comprising: a bypass channel connected to an oxygen-containing gas supply flow path through which an oxygen-containing gas to be supplied to a fuel cell stack flows and an oxygen-containing gas discharge flow path through which the oxygen-containing gas discharged from the fuel cell stack flows; a bypass valve disposed in the bypass channel; a first battery having a first battery voltage; a second battery having a second battery voltage higher than the first battery voltage; a step-down device configured to step down a voltage from the second battery; a switching unit configured to switch between the first battery and the step-down device to supply power to the bypass valve; and a control device including one or more processors that execute computer-executable instructions stored in a memory, wherein the one or more processors execute the computer-executable instructions to cause the control device to: control the switching unit to supply electric power to the bypass valve from the step-down device and detect a difference between a designated opening degree for the bypass valve and an output opening degree indicated by an opening degree signal output from the bypass valve by controlling an opening degree of the bypass valve, in a case where the voltage supplied from the first battery to the control device is equal to or lower than the predetermined voltage threshold.
2. 2 . The fuel cell system according to claim 1 , wherein the one or more processors cause the control device to: control the switching unit in a case where the voltage at a time when the control device is activated by electric power supplied from the first battery is equal to or lower than the predetermined voltage threshold.
3. 3 . A fuel cell system comprising: a bypass channel connected to an oxygen-containing gas supply flow path through which an oxygen-containing gas to be supplied to a fuel cell stack flows and an oxygen-containing gas discharge flow path through which the oxygen-containing gas discharged from the fuel cell stack flows; a bypass valve disposed in the bypass channel; a first battery having a first battery voltage; a second battery having a second battery voltage higher than the first battery voltage; a step-down device configured to step down a voltage from the second battery; a switching unit configured to switch between the first battery and the step-down device to supply power to the bypass valve; a compressor configured to supply the oxygen-containing gas to the fuel cell stack; and a control device including one or more processors that execute computer-executable instructions stored in a memory, wherein the one or more processors execute the computer-executable instructions to cause the control device to: control the switching unit to supply electric power to the bypass valve from the step-down device and control an opening degree of the bypass valve, in a case where the voltage supplied from the first battery to the control device is equal to or lower than the predetermined voltage threshold, and start electric power supply to the compressor after completion of the control of the opening degree.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This application is based upon and claims the benefit of priority from Japanese Patent Application No. 2022-055973 filed on Mar. 30, 2022, the contents of which are incorporated herein by reference. BACKGROUND OF THE INVENTION Field of the Invention The present invention relates to a fuel cell system to be mounted on a moving object or the like. Description of the Related Art In recent years, fuel cell stacks have attracted attention in various fields. For example, there is a fuel cell vehicle equipped with a fuel cell stack. A fuel cell vehicle is powered by an electric motor running on electricity generated by electrochemical reactions in the fuel cells. In a fuel cell vehicle, only water is discharged. Therefore, the fuel cell vehicle is more environmentally friendly in comparison with gasoline-powered vehicles or the like that emit CO2, NOx, SOx, and the like. The fuel cell stack may be mounted on other moving objects such as ships, aircrafts, robots and so on, in addition to automobiles. JP 2009-152131 A discloses a fuel cell system which operates a fuel cell stack. The fuel cell system disclosed in JP 2009-152131 A includes an oxygen-containing gas flow path through which an oxygen-containing gas to be supplied to the fuel cell stack flows, an oxygen-containing off-gas flow path through which an oxygen-containing off-gas discharged from the fuel cell stack flows, and a bypass channel for guiding a part of the oxygen-containing gas flowing through the oxygen-containing gas flow path to a discharge passage while bypassing the fuel cell stack. For a bypass valve provided in the bypass passage, opening degree learning (origin learning) is performed at a timing for returning the opening degree of the bypass valve to 0 during warm-up operation immediately after system activation. SUMMARY OF THE INVENTION However, in the fuel cell system disclosed in JP 2009-152131 A, if there is an instruction to open the bypass valve while the opening degree learning (origin learning) is being performed, the opening degree learning is forcibly terminated. Therefore, there is a concern that the origin learning is not completed. That is, it has been a problem to complete the opening degree learning without prolonging the time until the power generation by the fuel cell stack is started. An object of the present invention is to solve the above-described problem. To achieve the above-mentioned object, an aspect of the present invention is to provide a fuel cell system including: a bypass channel connected to an oxygen-containing gas supply flow path through which an oxygen-containing gas to be supplied to a fuel cell stack flows and an oxygen-containing gas discharge flow path through which the oxygen-containing gas discharged from the fuel cell stack flows; a bypass valve disposed in the bypass channel; a first battery having a first battery voltage; a second battery having a second battery voltage higher than the first battery voltage; a step-down device configured to step down a voltage supplied from the second battery; a switching unit configured to switch between the first battery and the step-down device to supply power to the bypass valve; and a control device including one or more processors that execute computer-executable instructions stored in a memory, wherein the one or more processors execute the computer-executable instructions to cause the control device to: control the switching unit to supply electric power to the bypass valve from the step-down device and control an opening degree of the bypass valve, in a case where the voltage supplied from the first battery to the control device is equal to or lower than the predetermined voltage threshold. According to the aspect of the present invention, it is possible to complete the opening degree learning for the bypass valve even when degradation of the first battery progresses. As a result, the opening degree learning can be completed without prolonging the time until the power generation by the fuel cell stack is started. The above and other objects, features and advantages of the present invention will become more apparent from the following description when taken in conjunction with the accompanying drawings in which a preferred embodiment of the present invention is shown by way of illustrative example. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic diagram showing a configuration of a fuel cell system according to an embodiment; and FIG. 2 is a flowchart showing a procedure of an activation control processing of the fuel cell system by the control device. DETAILED DESCRIPTION OF THE INVENTION FIG. 1 is a schematic diagram showing a configuration of a fuel cell system 10 according to an embodiment. The fuel cell system 10 may be mounted on a moving object such as a vehicle, a ship, an aircraft, a robot or the like. In the present embodiment, the fuel cell system 10 is mounted on a vehicle. The fuel cell system 10