# US 12,224,465 B2 · Voltage detection system and method of fuel cell stack

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- Number: US 12,224,465 B2
- Document ID: US12224465B2
- Status: Granted
- Kind: B2
- Application number: 17/677,758
- Filed: 2022-02-22
- Published: 2022-08-25
- Granted: 2025-02-11
- Earliest claimed: 2021-02-22
- Assignees: Hyundai Kefico Corporation
- Applicants: Hyundai Kefico Corporation
- Inventors: Sung Ho Kim; Ji Hye Park
- Web page: https://patentgrep.com/patent/US12224465B2

## CPC

- H01M 8/04559: {of fuel cell stacks}
- G01R 19/165: Indicating that current or voltage is either above or below a predetermined value or within or outside a predetermined range of values
- H01M 8/04679: {of fuel cell stacks}
- 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
- G01R: MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES (indicating correct tuning of resonant circuits H03J3/12)
- Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION

## Abstract

Disclosed is a voltage detection system of a fuel cell stack, which includes: a stack detection unit comparing input voltage and reference voltage when voltage of a fuel cell stack is input, and outputting a comparison result; and a determination unit determining whether negative voltage is generated in the fuel cell stack based on output voltage of the stack detection unit and a reference duty used for generation of the reference voltage.

## Claims

### Claim 1

A voltage detection system of a fuel cell stack, comprising:
a stack detection unit comparing an input voltage and a reference voltage when a voltage of a fuel cell stack is input and outputting a comparison result; and
a determination unit determining whether negative voltage is generated in the fuel cell stack based on an output voltage of the stack detection unit and a reference duty used for generation of the reference voltage.

### Claim 2 (depends on 1)

The voltage detection system of claim 1, wherein the stack detection unit comprises
an oscillation unit outputting the reference voltage by considering the reference duty,
a comparison unit comparing the reference voltage and the input voltage, and
an adjustment unit adjusting a voltage level for a comparison result of the comparison unit.

### Claim 3 (depends on 2)

The voltage detection system of claim 2, wherein the oscillation unit generates the reference voltage based on a positive voltage source and a negative voltage source.

### Claim 4 (depends on 3)

The voltage detection system of claim 3, wherein the oscillation unit generates the reference voltage of a triangular wave or sine wave form having a predetermined cycle according to the reference duty.

### Claim 5 (depends on 2)

The voltage detection system of claim 2, wherein the comparison unit outputs a comparison result of a high level when the input voltage is greater than the reference voltage, and outputs a comparison result of a low level when the input voltage is less than the reference voltage.

### Claim 6 (depends on 1)

The voltage detection system of claim 1, wherein the determination unit determines that the negative voltage is generated in the fuel cell stack when a duty of the output voltage is less than the reference duty.

### Claim 7

A method of detecting voltage of a fuel cell stack, comprising:
receiving voltage of a fuel cell stack;
comparing an input voltage and a reference voltage; and
determining whether negative voltage is generated in the fuel cell stack based on a comparison result of the comparison step and a reference duty used for generation of the reference voltage.

### Claim 8 (depends on 7)

The method of claim 7, further comprising:
outputting the reference voltage by considering a positive voltage source, a negative voltage source, and the reference duty before the input step.

### Claim 9 (depends on 7)

The method of claim 7, wherein in the comparing the input voltage and the reference voltage, a comparison result of a high level is output when the input voltage is greater than the reference voltage, and a comparison result of a low level is output when the input voltage is less than the reference voltage.

### Claim 10 (depends on 7)

The method of claim 7, wherein in the determining whether negative voltage is generated, it is determined that the negative voltage is generated in the fuel cell stack when a duty of the comparison result is less than the reference duty.

### Claim 11 (depends on 7)

The voltage detection method of claim 7, further comprising:
an adjustment step of adjusting a voltage level of the comparison result.