Wet state control method for fuel cell system and wet state control device for the same

Patent metadata

Field	Value
Publication number	US-10305127-B2
Application number	US-201616084345-A
Country	US
Kind code	B2
Filing date	Dec 8, 2016
Priority date	Mar 15, 2016
Publication date	May 28, 2019
Grant date	May 28, 2019

Abstract

Provided is a wet state control method for a fuel cell system in which cathode gas is supplied to a fuel cell while the cathode gas partially bypasses the fuel cell, the wet state control method being for controlling a wet state of the fuel cell by adjusting wet control parameters including a bypass valve opening degree, a cathode gas pressure, and a cathode gas flow rate. When the fuel cell is controlled to a wet side, at least either one of the cathode gas flow rate and the cathode gas pressure is adjusted in priority to adjustment of the bypass valve opening degree.

First claim

The invention claimed is:

1. A wet state control method for a fuel cell system in which cathode gas is supplied to a fuel cell while the cathode gas partially bypasses the fuel cell, the wet state control method being for controlling a wet state of the fuel cell by adjusting wet control parameters,
wherein the wet control parameters include at least a bypass valve opening degree, a cathode gas pressure, and a cathode gas flow rate, and
the method comprising:
controlling the fuel cell to a wet side such that at least either one of the cathode gas flow rate and the cathode gas pressure is adjusted in priority to adjustment of the bypass valve opening degree.

2. The wet state control method for the fuel cell system, according to claim 1 , the method comprising:
controlling the fuel cell to a dry side such that the bypass valve opening degree is adjusted in priority to adjustment of at least either one of the cathode gas flow rate and the cathode gas pressure.

3. A wet state control method for a fuel cell system in which cathode gas is supplied to a fuel cell while the cathode gas partially bypasses the fuel cell, the wet state control method being for controlling a wet state of the fuel cell by adjusting wet control parameters so that the wet state of the fuel cell approaches a target wet state,
wherein the wet control parameters include at least a bypass valve opening degree, a cathode gas pressure, and a cathode gas flow rate, and
the method comprising:
controlling the fuel cell to a wet side such that:
at least either one of decreasing of the cathode gas flow rate and increasing of the cathode gas pressure is performed; and
the bypass valve opening degree is increased so as to supplement the control on the fuel cell to the wet side by the at least either one of the decreasing of the cathode gas flow rate and the increasing of the cathode gas pressure.

4. The wet state control method for the fuel cell system, according to claim 3 , the method comprising:
controlling the fuel cell to the wet side such that:
a wet control request target flow rate of the cathode gas is calculated based on a minimum value of the cathode gas pressure and a minimum value of the bypass valve opening degree;
a wet control request target pressure of the cathode gas is calculated based on a detection value of the cathode gas flow rate and the minimum value of the bypass valve opening degree;
a target value of the bypass valve opening degree is calculated based on a detection value of the cathode gas pressure and the detection value of the cathode gas flow rate; and
the cathode gas flow rate, the cathode gas pressure, and the bypass valve opening degree are adjusted to approach the wet control request target flow rate, the wet control request target pressure, and the target value of the bypass valve opening degree, respectively.

5. The wet state control method for the fuel cell system, according to claim 3 , the method comprising:
controlling the fuel cell to a dry side such that:
an operation to decrease the bypass valve opening degree is performed; and
at least either one of increasing of the cathode gas flow rate and decreasing of the cathode gas pressure is performed so as to supplement the operation to decrease the bypass valve opening degree.

6. The wet state control method for the fuel cell system, according to claim 5 , the method comprising:
controlling the fuel cell to the dry side such that:
a target value of the bypass valve opening degree is calculated based on a minimum value of the cathode gas pressure and a minimum value of the cathode gas flow rate;
a wet control request target pressure of the cathode gas is calculated based on a detection value of the bypass valve opening degree and the minimum value of the cathode gas flow rate;
a wet control request target flow rate of the cathode gas is calculated based on the detection value of the bypass valve opening degree and a detection value of the cathode gas pressure; and
the bypass valve opening degree, the cathode gas pressure, and the cathode gas flow rate are adjusted to approach the target value of the bypass valve opening degree, the wet control request target pressure, and the wet control request target flow rate, respectively.

7. The wet state control method for the fuel cell system, according to claim 3 , the method comprising:
restricting the cathode gas pressure so that the cathode gas pressure does not exceed a pressure upper limit.

8. The wet state control method for the fuel cell system, according to claim 7 , the method comprising:
calculating the pressure upper limit based on at least one of a request load, a temperature of the fuel cell, and a target wet state.

9. The wet state control method for the fuel cell system according to claim 3 , the method comprising:
adjusting the cathode gas flow rate so as that the cathode gas flow rate does not become lower than a flow rate lower limit as a lower limit of the cathode gas flow rate.

10. The wet state control method for the fuel cell system, according to claim 9 , the method comprising:
setting the flow rate lower limit so that a request of a fuel cell supply flow rate is satisfied, the fuel cell supply flow rate being a flow rate of the cathode gas supplied to the fuel cell.

11. The wet state control method for the fuel cell system, according to claim 9 , the method comprising:
setting the flow rate lower limit so that local water clogging in the fuel cell is able to be prevented.

12. A wet state control device for a fuel cell system, the wet state control device comprising:
a fuel cell;
a cathode gas supply device configured to supply cathode gas to a cathode system including the fuel cell;
a bypass passage via which the cathode gas supplied from the cathode gas supply device to the fuel cell partially bypasses the fuel cell;
a bypass valve provided in the bypass passage;
a bypass valve opening degree adjusting device configured to adjust an opening degree of the bypass valve;
a cathode gas pressure adjusting device configured to adjust a cathode gas pressure;
a cathode gas flow rate adjusting device configured to adjust a cathode gas flow rate supplied from the cathode gas supply device to the cathode system;
a wet-state acquisition device configured to acquire a wet state of the fuel cell;
a bypass valve opening degree acquisition device configured to acquire an opening degree of the bypass valve;
a cathode gas pressure acquiring portion configured to acquire the cathode gas pressure;
a cathode gas flow rate acquiring portion configured to acquire the cathode gas flow rate; and
a priority setting portion configured to set priorities of adjustment of the bypass valve opening degree by the bypass valve opening degree adjusting device, adjustment of the cathode gas pressure by the cathode gas pressure adjusting device, and adjustment of the cathode gas flow rate by the cathode gas flow rate adjusting device, wherein
when the fuel cell is controlled to a wet side, the priority setting portion sets the priorities such that at least one of the adjustment of the cathode gas pressure by the cathode gas pressure adjusting device and the adjustment of the cathode gas flow rate by the cathode gas flow rate adjusting device is performed in priority to the adjustment of the bypass valve opening degree by the bypass valve opening degree adjusting device.

13. The wet state control device for the fuel cell system, according to claim 12 , wherein
when the fuel cell is controlled to a dry side, the priority setting portion sets the priorities such that adjustment of a bypass flow rate by the bypass valve openin

Assignees

• Nissan Motor

Inventors

• Chikugo Hayato
• Tomita Yousuke
• Aoki Tetsuya

Classifications

• H01M8/04828 Primary

  Humidity; Water content · CPC title

• H01M8/04768

  of the coolant · CPC title

• H01M8/04783

  Pressure differences, e.g. between anode and cathode · CPC title

• H01M8/04738

  of auxiliary devices, e.g. reformer, compressor, burner · CPC title

• H01M8/04753

  of fuel cell reactants · CPC title