Controlling cathode stoichiometry in fuel cells

Patent metadata

Field	Value
Publication number	US-12388098-B2
Application number	US-202217676390-A
Country	US
Kind code	B2
Filing date	Feb 21, 2022
Priority date	Feb 21, 2022
Publication date	Aug 12, 2025
Grant date	Aug 12, 2025

Abstract

Systems and methods for managing cathode stoichiometry of an electrochemical cell are disclosed. A system may include a fuel cell, a compressor for supplying air to the fuel cell and an oxygen sensor proximate to or downstream of an outlet of a cathode chamber of the fuel cell. An operation speed of the compressor or flow rate of the air may be adjusted by, for example, a controller after receiving data from the sensor regarding the amount of residual oxygen. For example, the operation speed/flow rate may be increased or decreased to achieve a cathode stoichiometry of about 1.00.

First claim

What is claimed is:

1. A power system comprising:
a fuel cell defining (i) a cathode chamber housing a cathode, and (ii) an anode chamber housing an anode, the fuel cell having an electrolyte between the cathode and anode, and defining an inlet and an outlet providing fluid communication to the cathode chamber;
a compressor configured to provide an oxidant to the cathode chamber of the fuel cell; and
a first oxidant sensor disposed proximate to or downstream from the outlet; and
a second oxidant sensor disposed proximate to or upstream from the inlet, wherein the first oxidant sensor and second oxidant sensor are a same type of sensor.

2. The power system of claim 1 , wherein the oxidant is oxygen, and the first oxidant sensor is configured to detect a residual amount of oxygen in an exhaust gas of the fuel cell.

3. The power system of claim 1 , wherein the first oxidant sensor is a first universal exhaust gas oxygen sensor.

4. The power system of claim 1 , further comprising a controller configured to receive data from the first oxidant sensor and control the compressor based on the data.

5. The power system of claim 4 , wherein the controller is configured to increase an operation speed of the compressor when a residual amount of oxidant defined by the data is below a first threshold amount.

6. The power system of claim 5 , wherein the controller is configured to decrease the operation speed of the compressor when the residual amount of oxidant is above a second threshold amount.

7. A vehicle power system comprising:
fuel cell having a cathode passage adjacent to a cathode, the cathode passage defining an inlet and an outlet, the cathode passage being in fluid communication with an air intake system via the inlet and an exhaust system via the outlet, the air intake system including an airflow inducing device configured to provide an airflow during operation and the exhaust system including a first oxygen sensor configured to sense a residual amount of oxygen, a second oxygen sensor configured sense an amount of oxygen provided to the fuel cell, and a bypass valve in fluid communication with the air intake system and exhaust system and configured to provide airflow to the exhaust system without passing the airflow through the fuel cell, the first oxygen sensor and second oxygen sensor being the same type of sensor; and
a controller configured to initiate a command to supply oxygen to the fuel cell such that
responsive to the residual amount of oxygen being within a predetermined range, an operation speed of the airflow inducing device is maintained, and
responsive to the residual amount of oxygen being outside the predetermined range, the operation speed of the airflow inducing device is adjusted.

8. The vehicle power system of claim 7 , wherein the airflow inducing device is a compressor.

9. The vehicle power system of claim 8 , wherein the controller is further configured to initiate the command such that, responsive to the residual amount of oxygen being greater than the predetermined range, the operation speed of the compressor is decreased.

10. The vehicle power system of claim 9 , wherein the controller is further configured to initiate the command such that, responsive to the residual amount of oxygen being less than the predetermined range, the operation speed of the compressor is increased.

11. The vehicle power system of claim 10 , wherein the predetermined range is configured to maintain a cathode stoichiometry of 1.0 to 2.0.

12. The vehicle power system of claim 11 , wherein the predetermined range is configured to maintain the cathode stoichiometry to 1.1 to 1.9.

13. The vehicle power system of claim 12 , wherein the predetermined range is configured to maintain the cathode stoichiometry to 1.2 to 1.8.

14. A method of controlling operation of an electrochemical cell comprising:
performing a hydrogen purge or initiating a hydrogen-protective-state; and
providing an oxidant to a fuel cell, the fuel cell including an inlet and an outlet, wherein the oxidant is provided at a flow rate such that
responsive to a residual amount of oxidant in a fuel cell exhaust being more than a lower threshold amount, the flow rate is at least maintained, and
responsive to the residual amount of oxidant being less than the lower threshold amount, the flow rate is increased,
wherein the residual amount of oxidant is determined by a first sensor disposed proximate the inlet and a second sensor disposed proximate the outlet, the first and second sensors being a same type of sensor.

15. The method of claim 14 , wherein responsive to the residual amount of oxidant being more than an upper threshold amount, the flow rate is decreased.

16. The method of claim 15 , wherein the flow rate is increased and decreased by controlling an operation speed of a compressor.

17. The method of claim 15 , wherein the lower and upper threshold amounts are configured to maintain a cathode stoichiometry of 0.95 to 1.05.

18. The method of claim 14 , further comprising, responsive to the residual amount of oxidant being different than an anticipated amount, alerting a user to that operation of the electrochemical cell is abnormal.

19. The power system of claim 1 , wherein the first oxidant sensor and second oxidant sensor are both universal exhaust gas oxygen (UEGO) sensors.

Assignees

• Ford Global Tech Llc

Inventors

• Pryor Martin Dale
• Ford Patrick J
• Mathie Craig Michael

Classifications

• H01M8/04425

  at auxiliary devices, e.g. reformers, compressors, burners · CPC title

• H01M2250/20

  Fuel cells in motive systems, e.g. vehicle, ship, plane · CPC title

• H01M8/04671

  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

• Y02E60/50

  Fuel cells · CPC title