Fuel Cell System Having Maximum Cell Voltage Constraint

Patent metadata

Field	Value
Publication number	US-2023253588-A1
Application number	US-202217668416-A
Country	US
Kind code	A1
Filing date	Feb 10, 2022
Priority date	Feb 10, 2022
Publication date	Aug 10, 2023
Grant date	—

Abstract

A system, such as for a fuel cell electric vehicle, includes a fuel cell stack (FCS) and a controller. The FCS is configured to provide, such as for vehicle propulsion, a stack power commensurate with a stack power request. The stack power is a product of a stack current of the FCS and a stack voltage of the FCS. The controller is configured to, upon the stack voltage meeting a predetermined threshold, control the FCS to increase the stack current to cause the FCS to provide an increased stack power commensurate with an increased stack power request.

First claim

What is claimed is:

1 . A system comprising:
a fuel cell stack (FCS) configured to provide a stack power commensurate with a stack power request, the stack power being a product of a stack current and a stack voltage of the FCS; and a controller configured to, upon the stack voltage meeting a predetermined threshold, control the FCS to increase the stack current to cause the FCS to provide an increased stack power commensurate with an increased stack power request.

2 . The system of claim 1 wherein:
a characteristic of the FCS is that the stack voltage inversely depends on the stack current, whereby the stack voltage is decreased less than the predetermined threshold upon the controller controlling the FCS to increase the stack current.

3 . The system of claim 1 wherein:
the FCS is comprised of a number of fuel cells connected in series, the stack voltage is a summation of voltages of the fuel cells, and a maximum cell voltage is either the largest voltage of the voltages of the fuel cells or the stack voltage divided by the number of fuel cells; and
the stack voltage is considered to meet the predetermined threshold upon the maximum cell voltage meeting a predetermined maximum voltage.

4 . The system of claim 3 wherein:
a characteristic of each fuel cell is that the voltage of the fuel cell inversely depends on the stack current, whereby the voltages of the fuel cells are decreased less than the predetermined maximum voltage upon the controller controlling the FCS to increase the stack current.

5 . The system of claim 1 wherein:
the controller is further configured to, upon the stack power commensurate with the stack power request being lower than a calculated minimum power, control the FCS to increase the stack current to cause the FCS to provide the increased stack power commensurate with the increased stack power request.

6 . The system of claim 5 wherein:
the controller is further configured to set the calculated minimum power dependent on an operating condition of the FCS.

7 . The system of claim 6 wherein:
the controller is further configured to use a gradient calculation in setting the calculated minimum power.

8 . The system of claim 1 wherein:
the controller is further configured to, while the stack voltage is less than the predetermined threshold, control the FCS to cause the FCS to provide the stack power commensurate with the stack power request.

9 . The system of claim 1 wherein:
stack power provided by the FCS is for use in propelling a vehicle.

10 . A vehicle comprising:
a fuel cell system (FCS) configured to provide a stack power for vehicle propulsion, the stack power being a product of a stack current and a stack voltage of the FCS; a controller configured to, in response to a stack power request, adjust the stack current to a desired amount corresponding to the stack power request to cause the FCS to provide a stack power commensurate with the stack power request; and wherein the controller is further configured to, upon the stack voltage meeting a predetermined threshold, increase the stack power request to an increased stack power request and adjust the stack current to an increased desired amount corresponding to the increased stack power request to cause the FCS to provide an increased stack power commensurate with the increased stack power request.

11 . The vehicle of claim 10 wherein:
a characteristic of the FCS is that the stack voltage inversely depends on the stack current, whereby the stack voltage is decreased less than the predetermined threshold upon the controller adjusting the stack current to the increased desired amount corresponding to the increased stack power request.

12 . The vehicle of claim 11 wherein:
the FCS includes a fuel cell stack comprised of a number of fuel cells connected in series, the stack voltage is a summation of voltages of the fuel cells, and a maximum cell voltage is either the largest voltage of the voltages of the fuel cells or the stack voltage divided by the number of fuel cells; and
the stack voltage is considered to meet the predetermined threshold upon the maximum cell voltage meeting a predetermined maximum voltage.

13 . The vehicle of claim 12 wherein:
a characteristic of each fuel cell is that the voltage of the fuel cell inversely depends on the stack current, whereby the voltages of the fuel cells are decreased less than the predetermined maximum voltage upon the controller controlling the FCS to increase the stack current.

14 . The vehicle of claim 12 wherein:
the controller is further configured to, upon a stack power commensurate with a stack power request being lower than a calculated minimum power, increase the stack power request to the increased stack power request and adjust the stack current to the increased desired amount corresponding to the increased stack power request to cause the FCS to provide the increased stack power commensurate with the increased stack power request.

15 . The vehicle of claim 14 wherein:
the controller is further configured to set the calculated minimum power dependent on an operating condition of the FCS.

16 . The vehicle of claim 10 further comprising:
a traction battery configured to provide a battery power for vehicle propulsion.

17 . A method for use with a fuel cell stack (FCS) configured to provide a stack power, the stack power being a product of a stack current and a stack voltage of the FCS, the method comprising:
in response to a stack power request, adjusting the stack current to a desired amount corresponding to the stack power request to cause the FCS to provide a stack power commensurate with the stack power request; and upon either the stack voltage meeting a predetermined threshold or the stack power being lower than a calculated minimum power, increasing the stack power request to an increased stack power request and adjusting the stack current to an increased desired amount corresponding to the increased stack power request to cause the FCS to provide an increased stack power commensurate with the increased stack power request.

18 . The method of claim 17 further comprising:
adjusting the calculated minimum power dependent on an operating condition of the FCS.

19 . The method of claim 18 wherein:
adjusting the calculated minimum power dependent on an operating condition of the FCS involves use of a gradient calculation.

20 . The method of claim 17 wherein:
stack power provided by the FCS is for use in propelling a vehicle.

Assignees

• Ford Global Tech Llc

Inventors

• Qiu Zeng
• Johri Rajit
• Sanderson Jr William F
• Wang Hao

Classifications

• B60L50/75 Primary

  using propulsion power supplied by both fuel cells and batteries · CPC title

• B60L58/30

  for monitoring or controlling fuel cells · CPC title

• B60L58/40

  for controlling a combination of batteries and fuel cells · CPC title

• H01M8/04932 Primary

  of the individual fuel cell · CPC title

• H01M8/04992

  characterised by the implementation of mathematical or computational algorithms, e.g. feedback control loops, fuzzy logic, neural networks or artificial intelligence · CPC title