# US 12,009,500 B2 · Power net system of a fuel cell and a method for controlling same

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 12,009,500 B2
- Document ID: US12009500B2
- Status: Granted
- Kind: B2
- Application number: 17/481,172
- Filed: 2021-09-21
- Published: 2022-06-02
- Granted: 2024-06-11
- Earliest claimed: 2020-11-27
- Assignees: Hyundai Motor Company; Kia Corporation
- Applicants: Hyundai Motor Company; Kia Corporation
- Inventors: Jong Hyun Lee; Ju Han Kim
- Web page: https://patentgrep.com/patent/US12009500B2

## CPC

- B60L 1/00: Supplying electric power to auxiliary equipment of vehicles (circuit arrangements for charging batteries H02J7/00)
- H01M 16/006: {of fuel cells with rechargeable batteries}
- B60L 50/75: using propulsion power supplied by both fuel cells and batteries
- B60L 58/20: having different nominal voltages
- B60L 58/40: for controlling a combination of batteries and fuel cells
- H01M 8/04302: applied during start-up
- H01M 8/04303: applied during shut-down
- H01M 8/04589: {of fuel cell stacks}
- H01M 8/04895: {Current}
- H01M 8/0494: {of fuel cell stacks}
- H01M 8/04947: {of auxiliary devices, e.g. batteries, capacitors}
- H01M 8/04955: Shut-off or shut-down of fuel cells
- H01M 8/10: Fuel cells with solid electrolytes
- H02J 7/34: Parallel operation in networks using both storage and other DC sources, e.g. providing buffering (H02J7/14 takes precedence)
- H01M 2008/1095: {Fuel cells with polymeric electrolytes}
- H01M 2250/20: Fuel cells in motive systems, e.g. vehicle, ship, plane
- H02J 2101/30: Fuel cells
- Y02B 90/10: Applications of fuel cells in buildings
- Y02E 60/10: Energy storage using batteries
- Y02E 60/50: Fuel cells
- Y02T 10/70: Energy storage systems for electromobility, e.g. batteries
- Y02T 90/40: Application of hydrogen technology to transportation, e.g. using fuel cells
- B60L: PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES (arrangements or mounting of electrical propulsion units or of plural diverse prime-movers for mutual or common propulsion in vehicles B60K1/00, B60K6/20; arrangements or mounting of electrical gearing in vehicles B60K17/12, B60K17/14; preventing wheel slip by reducing power in rail vehicles B61C15/08; dynamo-electric machines H02K; control or regulation of electric motors H02P); SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES (electric coupling devices combined with mechanical couplings of vehicles B60D1/64; electric heating for vehicles B60H1/00); ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL (control or regulation of electric motors H02P); MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
- H01M: PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H02J: ELECTRIC POWER NETWORKS; CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- Y02B: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
- Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION

## Abstract

A power net system of a fuel cell and a method for controlling the same are provided. The power net system includes: a fuel cell to generate electric power through a reaction of a fuel gas and an oxidation gas; batteries to be charged by the electric power generated by the fuel cell or discharged to supply electric power; main lines electrically connecting the fuel cell and the batteries; main relays provided in the main lines to open or allow electrical connections between the fuel cell and the batteries; COD lines branched from the main lines between the fuel cell and the main relays and provided with a COD device to consume input electric power; COD relays provided in the COD lines to open or allow electrical connections to the COD device through the COD lines; and a controller to control the main relays or the COD relays to supply electric power charged in the batteries to the fuel cell.

## Claims

### Claim 1

A power net system of a fuel cell, the power net system comprising:
a fuel cell configured to generate electric power through a reaction of a fuel gas and an oxidation gas;
batteries configured to be charged by the electric power generated by the fuel cell or be discharged to supply electric power;
main lines electrically connecting the fuel cell and the batteries;
main relays provided in the main lines and configured to open or allow electrical connections between the fuel cell and the batteries;
COD lines branched from the main lines between the fuel cell and the main relays and provided with a COD device configured to consume input electric power and be immersed in a coolant that cools the fuel cell;
COD relays provided in the COD lines and configured to open or allow electrical connections to the COD device through the COD lines; and
a controller configured to control the main relays or the COD relays to supply electric power charged in the batteries to the fuel cell.

### Claim 2 (depends on 1)

The power net system of claim 1, wherein the main lines comprise a main positive electrode line connecting a positive electrode of the fuel cell and positive electrodes of the batteries and a main negative electrode line connecting a negative electrode of the fuel cell and negative electrodes of the batteries, and
wherein the main relays comprise a first main relay located in the main positive electrode line and a second main relay located in the main negative electrode line.

### Claim 3 (depends on 2)

The power net system of claim 2, wherein the COD lines comprise a positive electrode COD line branched from the main positive electrode line on a side, which is close to the fuel cell with respect to the first main relay, and a negative electrode COD line branched from the main negative electrode line on a side, which is close to the fuel cell with respect to the second main relay, and the COD device is connected to the positive electrode COD line and the negative electrode COD line to consume the electric power.

### Claim 4 (depends on 3)

The power net system of claim 3, further comprising:
a first COD relay provided in the positive electrode COD line or the negative electrode COD line to open or allow an electrical connection.

### Claim 5 (depends on 4)

The power net system of claim 4, wherein at least one of the main positive electrode line or the main negative electrode line is provided with a diode that allows flows of currents only in one direction, and
wherein the power net system further comprises:
an EHP line electrically connecting the diode and the fuel cell in the main positive electrode line or the main negative electrode line and the first COD relay and the COD device in the positive electrode COD line or the negative electrode COD line; and
a second COD relay provided in the EHP line to open or allow an electrical connection.

### Claim 6 (depends on 3)

The power net system of claim 3, wherein the COD device maintains a state in which the positive electrode COD line and the negative electrode COD line are electrically connected to each other and the consumed electric power is controlled through switching control, and
wherein the controller varies the electric power consumed in the COD device by switching the COD device.

### Claim 7 (depends on 1)

The power net system of claim 1, wherein the main lines comprise a main positive electrode line connecting a positive electrode of the fuel and positive electrodes of the batteries and a main negative electrode line connecting a negative electrode of the fuel cell and negative electrodes of the batteries, and
wherein the power net system further comprises:
a current sensor located in the main positive electrode line or the main negative electrode line on a side, which is closer to the fuel cell, and configured to sense a current that is output from the fuel cell or input to the fuel cell.

### Claim 8 (depends on 7)

The power net system of claim 7, wherein the COD lines comprise a positive electrode COD line branched from the main positive electrode line on a side, which is close to the fuel cell with respect to the first main relay, and a negative electrode COD line branched from the main negative line on a side, which is close to the fuel cell with respect to the second main relay, and
wherein the power net system further comprises:
an EHP line connecting the main positive electrode line and the negative electrode COD line when the current sensor is located in the main positive electrode line, or connecting the main negative electrode line and the positive COD line when the current sensor is located in the main negative line.

### Claim 9 (depends on 1)

A method for controlling the power net system of the fuel cell of claim 1, the method comprising:
stopping generation of electric power by the fuel cell;
supplying the electric power stored in the batteries to the fuel cell such that a fuel of a cathode flows to an anode; and
generating electric power through a reaction of the fuel gas and the oxidation gas in the fuel cell.

### Claim 10 (depends on 9)

The method of claim 9, further comprising:
performing a shutdown control of, when the generation of the electric power by the fuel cell is stopped through a start-off of the fuel cell in the stopping of generation of electric power by the fuel cell, decreasing the voltage of the fuel cell, after the generation of the electric power by the fuel cell is stopped,
wherein the performing of the shutdown control comprises:
opening the connections between the fuel cell and the batteries by opening the main relays after the electric power is consumed by the COD device in connection states of the COD relays.

### Claim 11 (depends on 9)

The method of claim 9, wherein the performing of the shutdown control comprises:
sequentially opening the main positive electrode line connecting the positive electrode of the fuel cell and the positive electrodes of the batteries and the main negative electrode line connecting the negative electrode of the fuel cell and the negative electrodes of the batteries.

### Claim 12 (depends on 9)

The method of claim 9, further comprising:
determining whether generation of electric power by the fuel cell is required through a start-on of the fuel cell or a release of an FC stop mode of the fuel cell, before hydrogen flows from the cathode to the anode,
wherein the flowing of the hydrogen from the cathode to the anode comprises:
supplying the electric power stored in the batteries to the fuel cell when generation of electric power by the fuel cell is required.

### Claim 13 (depends on 9)

The method of claim 9, wherein the flowing of the hydrogen from the cathode to the anode comprises:
discharging the batteries by controlling a bidirectional converter located between the fuel cell and the batteries and supplying the electric power discharged from the batteries to the fuel cell via the COD lines.

### Claim 14 (depends on 9)

The method of claim 9, wherein the flowing of the hydrogen from the cathode to the anode comprises:
closing the positive COD line electrically connecting a side of the main positive line connecting the positive electrode of the fuel cell and the positive electrodes of the batteries, which is close to the batteries, and the positive electrode of the COD device, and closing the EHP line electrically connecting a side of the main positive electrode line, which is close to the fuel cell, and the negative electrode of the COD device.

### Claim 15 (depends on 14)

The method of claim 14, wherein the flowing of the hydrogen from the cathode to the anode comprises:
changing the electric power consumed in the COD device through a switching control of the COD device that maintains a state in which the positive electrode COD line and the negative electrode COD line are electrically connected to each other.