Fuel cell system

Patent metadata

Field	Value
Publication number	US-9905867-B2
Application number	US-201314655993-A
Country	US
Kind code	B2
Filing date	Nov 13, 2013
Priority date	Dec 28, 2012
Publication date	Feb 27, 2018
Grant date	Feb 27, 2018

Abstract

A fuel cell system sets the larger one of a stack request compressor supply flow rate calculated based on a request of a fuel cell stack and a system request compressor supply flow rate calculated based on a request by the fuel cell system as a target compressor supply flow rate and controls a compressor according to the target compressor supply flow rate. The fuel cell system also controls a bypass valve based on a stack supply flow rate and a target stack supply flow rate to be supplied to the fuel cell stack. The fuel cell system fixes the bypass valve or limits the drive of the bypass valve when the system request compressor supply flow rate is set as the target compressor supply flow rate and the stack supply flow rate becomes smaller than the target stack supply flow rate.

First claim

The invention claimed is:

1. A fuel cell system, comprising:
a cathode gas supply passage through which a cathode gas is supplied to a fuel cell stack;
a compressor provided on the cathode gas supply passage;
a bypass passage through which a part of the cathode gas discharged from the compressor is eliminated by bypassing the fuel cell stack;
a bypass valve provided on the bypass passage, the bypass valve being configured to adjust a flow rate of the cathode gas flowing through the bypass passage;
a flow rate sensor detecting a stack supply flow rate, the stack supply flow rate being a flow rate of the cathode gas supplied to the fuel cell stack; and
a programmable controller programmed to:
set a larger one of a stack request compressor supply flow rate and a system request compressor supply flow rate as a target compressor supply flow rate, the stack request compressor supply flow rate being calculated based on a request by the fuel cell stack, the system request compressor supply flow rate being calculated based on a request by the fuel cell system;
control the compressor according to the set target compressor supply flow rate;
control the bypass valve based on the stack supply flow rate and a target stack supply flow rate to be supplied to the fuel cell stack; and
fix the bypass valve or limit driving of the bypass valve when the system request compressor supply flow rate is set as the target compressor supply flow rate and the stack supply flow rate becomes smaller than the target stack supply flow rate.

2. The fuel cell system according to claim 1 , wherein the controller is further programmed to:
calculate the target stack supply flow rate based on a load on the fuel cell stack, and
calculate the stack request compressor supply flow rate based on the stack supply flow rate and the target stack supply flow rate so as to cause the stack supply flow rate to reach the target stack supply flow rate.

3. The fuel cell system according to claim 1 , wherein the controller is further programmed to:
calculate the stack request compressor supply flow rate by executing a feedback control only when the system request compressor supply flow rate is set as the target compressor supply flow rate and the stack supply flow rate is smaller than the target stack supply flow rate, time-integration of a deviation between the stack supply flow rate and the target stack supply flow rate being calculated in the feedback control.

4. The fuel cell system according to claim 1 , further comprising:
a cathode gas discharging passage through which the cathode gas and cathode off-gas flow, the cathode gas having flowed in the bypass passage, the cathode off-gas being discharged from the fuel cell stack; and
an anode gas discharging passage through which anode gas discharged from the fuel cell stack is discharged to the cathode gas discharging passage,
wherein the system request compressor supply flow rate is a target value of a compressor supply flow rate necessary for controlling hydrogen concentration within the cathode gas discharging passage to a predetermined value or less.

5. A fuel cell system, comprising:
a cathode gas supply passage through which a cathode gas is supplied to a fuel cell stack;
a compressor provided on the cathode gas supply passage;
a bypass passage through which a part of the cathode gas discharged from the compressor is eliminated by bypassing the fuel cell stack;
a bypass valve provided on the bypass passage, the bypass valve being configured to adjust a flow rate of the cathode gas flowing through the bypass passage;
a stack supply flow rate detecting means configured to detect a stack supply flow rate, the stack supply flow rate being a flow rate of the cathode gas supplied to the fuel cell stack;
a compressor control means configured to set a larger one of a stack request compressor supply flow rate and a system request compressor supply flow rate as a target compressor supply flow rate, the stack request compressor supply flow rate being calculated based on a request by the fuel cell stack, the system request compressor supply flow rate being calculated based on a request by the fuel cell system, the compressor control means being configured to control the compressor according to the set target compressor supply flow rate;
a bypass valve control means configured to control the bypass valve based on the stack supply flow rate and a target stack supply flow rate to be supplied to the fuel cell stack; and
a regulating means configured to fix the bypass valve or limit driving of the bypass valve when the system request compressor supply flow rate is set as the target compressor supply flow rate and the stack supply flow rate becomes smaller than the target stack supply flow rate.

Assignees

• Nissan Motor

Inventors

• Asai Yoshitomo
• Takeda Hiroshi

Classifications

• H01M8/04089 Primary

  of gaseous reactants · CPC title

• H01M8/04201 Primary

  Reactant storage and supply, e.g. means for feeding, pipes · CPC title

• H01M2008/1095

  Fuel cells with polymeric electrolytes · CPC title

• H01M8/04395

  of cathode reactants at the inlet or inside the fuel cell · CPC title

• H01M8/04805

  of fuel cell exhausts · CPC title