# US 10,312,534 B2 · System and method for recovering performance of fuel cell

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- Number: US 10,312,534 B2
- Document ID: US10312534B2
- Status: Granted
- Kind: B2
- Application number: 13/868,391
- Filed: 2013-04-23
- Published: 2014-06-19
- Granted: 2019-06-04
- Earliest claimed: 2012-12-18
- Assignees: Hyundai Motor Company
- Applicants: Hyundai Motor Company
- Inventors: Hyun Suk Choo; Dae Keun Chun; Hwan Soo Shin; Sung Keun Lee; Jae Hyuk Lee
- Web page: https://patentgrep.com/patent/US10312534B2

## CPC

- H01M 8/04238: {Depolarisation}
- H01M 8/04228: during shut-down
- H01M 8/04303: applied during shut-down
- H01M 4/92: Metals of platinum group (H01M4/94 {, H01M4/9058} take precedence)
- H01M 2008/1095: {Fuel cells with polymeric electrolytes}
- H01M 2250/20: Fuel cells in motive systems, e.g. vehicle, ship, plane
- Y02E 60/50: Fuel cells
- Y02T 90/40: Application of hydrogen technology to transportation, e.g. using fuel cells
- H01M: PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION

## Abstract

A method for recovering performance of a degraded polymer electrolyte fuel cell stack through electrode reversal. In detail, oxide films formed on the surface of platinum of a cathode is removed through an electrode reversal process that creates a potential difference between an anode and the cathode by supplying air to the anode instead of hydrogen and supplying a fuel to the cathode instead of air, thus rapidly recovering the performance of a degraded polymer electrolyte fuel cell stack.

## Claims

### Claim 1

A method for recovering performance of a fuel cell stack, the method comprising:
creating a potential difference between an anode and a cathode by supplying air to the anode of the fuel cell stack instead of hydrogen and supplying hydrogen to the cathode instead of air for a predetermined period while maintaining an open circuit voltage of the fuel cell stack, and, at the same time, supplying coolant that is below a predetermined temperature to the fuel cell stack so that droplets are retained in the anode and the cathode; and
shutting down the fuel cell stack for a predetermined time such that a vacuum is created in the anode and the cathode by crossing over of the hydrogen and oxygen in the air between the cathode and the anode, and consuming the hydrogen and the oxygen crossed over, thereby initiate swelling in which droplets retained in the anode and the cathode move toward each other through fine pores of an electrolyte membrane due to the vacuum created in the anode and the cathode;
wherein the potential difference is created and the coolant is supplied at the same time, and
wherein the supplied coolant reduces a temperature of a membrane between the cathode and the anode.

### Claim 2 (depends on 1)

The method of claim 1, wherein the air is supplied to the anode and the fuel (hydrogen) is supplied to the cathode until a potential difference of 1.0 V is created between the anode and the cathode.

### Claim 3 (depends on 1)

The method of claim 1, wherein the potential difference is created and the coolant is supplied at the same time for 10 minutes, and then the fuel cell stack is shut down for 10 minutes.

### Claim 4 (depends on 1)

The method of claim 1, wherein creating a potential difference, supplying the coolant, and shutting down the fuel cell stack, are repeated at least three times.

### Claim 5 (depends on 1)

The method of claim 1, wherein while creating a potential difference, an overpotential applied to the oxidation of a platinum (Pt) catalyst present in the cathode and an overpotential applied to a reduction of a platinum oxide act as a driving force for an electrochemical reaction to increase a reduction rate of the platinum oxide on a surface of the cathode.

### Claim 6 (depends on 1)

The method of claim 1, wherein when the potential difference is created, a potential difference above a predetermined threshold is generated in the anode to desorb carbon monoxide impurities remaining in the anode.