# US 2019/0245228 A1 · Explosion-protected fuel cell system and method for deactivating a fuel cell system

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- Number: US 2019/0245228 A1
- Document ID: US20190245228A1
- Status: Published application
- Kind: A1
- Application number: 16/321,735
- Filed: 2017-07-27
- Published: 2019-08-08
- Earliest claimed: 2016-07-29
- Assignees: Proton Motor Fuel Cell GmbH
- Applicants: Proton Motor Fuel Cell GmbH
- Inventors: ACHIM LANZINGER
- Web page: https://patentgrep.com/patent/US20190245228A1

## CPC

- H01M 8/04955: Shut-off or shut-down of fuel cells
- H01M 8/04089: of gaseous reactants
- H01M 8/04201: {Reactant storage and supply, e.g. means for feeding, pipes}
- H01M 8/04231: {Purging of the reactants}
- H01M 8/04753: {of fuel cell reactants}
- H01M 2008/1095: {Fuel cells with polymeric electrolytes}
- H01M 2250/20: Fuel cells in motive systems, e.g. vehicle, ship, plane
- Y02E 60/32: Hydrogen storage
- Y02E 60/50: 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

## Abstract

The invention relates to a fuel cell system having lines for feeding hydrogen from a high-pressure hydrogen reservoir into a fuel cell assembly. The lines have a high-pressure region, a medium-pressure region, and a fuel cell operating-pressure region. The lines of the medium-pressure region are pressure-relieved upon deactivation of the fuel cell system in order to avoid hydrogen diffusing out during standstill periods of the fuel cell system, and to thus avoid the formation of explosive hydrogen/air mixtures. The invention also relates to a tank module, which is configured for pressure relieving, to a method of deactivating and re-activating the fuel cell system, to the use of a 3/2-way valve for pressure-relieving the medium-pressure region of the hydrogen lines of a fuel cell system, and to a motor vehicle having a fuel cell system or tank module.

## Claims

### Claim at position 1

1-16. (canceled)

### Claim 17

A fuel cell system, comprising:
a fuel cell assembly,
a hydrogen feed line for feeding hydrogen to the fuel cell assembly,
a pressure reducer in the hydrogen feed line,
a high-pressure hydrogen reservoir,
a hydrogen line for feeding hydrogen from the high-pressure hydrogen reservoir into a hydrogen supply line for the fuel cell assembly, which connects the hydrogen line and the hydrogen feed line with each other,
a pressure reducer in the hydrogen line for reducing the hydrogen pressure,
a 3/2-way valve in the hydrogen line downstream of the pressure reducer or in the hydrogen supply line, and
a hydrogen pressure relief line connected to the 3/2-way valve,
wherein the 3/2-way valve, in a first switching position, allows the flow of gas from the high-pressure hydrogen reservoir into the hydrogen supply line, and in a second switching position, allows the flow of gas from the hydrogen supply line into the hydrogen pressure relief line.

### Claim 18 (depends on 17)

The fuel cell system of claim 17, wherein the fuel cell system comprises a shut-off valve in the hydrogen feed line upstream of the pressure reducer and/or the high-pressure hydrogen reservoir comprises a main shut-off valve.

### Claim 19 (depends on 17)

The fuel cell system of claim 17, wherein the opening cross-section of the 3/2-way valve is dimensioned small enough, or wherein the hydrogen pressure relief line has a throttle location with such a small opening cross-section provided therein that always only so small amounts of hydrogen can escape that the lower explosive limit of hydrogen in air is not reached at the outlet of the hydrogen pressure relief line.

### Claim 20 (depends on 17)

The fuel cell system of claim 17, further comprising a check valve having an opening pressure of less than 10 kPa (100 mbar) in the hydrogen pressure relief line.

### Claim 21 (depends on 17)

The fuel cell system of claim 17, wherein the fuel cell system is designed so that, by disconnection of an electrical load from the fuel cell system or by detection of an emergency situation, switching of the 3/2-way valve from the first switching position to the second switching position is triggered and/or, by activation of the fuel cell assembly, switching of the 3/2-way valve from the second switching position to the first switching position is triggered.

### Claim 22

A tank module for supplying a fuel cell assembly with hydrogen, comprising:
a high-pressure hydrogen reservoir,
a hydrogen line for feeding hydrogen from the high-pressure reservoir into a hydrogen supply line for the fuel cell assembly,
a pressure reducer in the hydrogen line for reducing the hydrogen pressure,
a 3/2-way valve in the hydrogen line downstream of the pressure reducer, and
a hydrogen pressure relief line connected to the 3/2-way valve,
wherein the 3/2-way valve, in a first switching position, permits the flow of gas from the high-pressure hydrogen reservoir into the hydrogen supply line, and in a second switching position, permits the flow of gas from the hydrogen supply line into the hydrogen pressure relief line.

### Claim 23 (depends on 22)

The tank module of claim 22, wherein the high-pressure hydrogen reservoir comprises a main shut-off valve.

### Claim 24 (depends on 22)

The tank module of claim 22, wherein the opening cross-section of the 3/2-way valve is dimensioned small enough, or wherein the hydrogen pressure relief line has a throttle location with such a small opening cross-section provided therein that always only so small amounts of hydrogen can escape that the lower explosive limit of hydrogen in air is not reached at the outlet of the hydrogen pressure relief line.

### Claim 25 (depends on 22)

The tank module of claim 22, wherein the tank module is designed such that, upon deactivation of the fuel cell assembly or upon detection of an emergency situation, the 3/2-way valve is automatically switched to the second switching position thereof and/or is automatically switched to the first switching position thereof when the fuel cell assembly is put into operation.

### Claim 26 (depends on 22)

The tank module of claim 22, further comprising a check valve having an opening pressure of less than 10 kPa (100 mbar) in the hydrogen pressure relief line.

### Claim 27

A method of deactivating a fuel cell system comprising:
providing a fuel cell system comprising
a fuel cell assembly,
a hydrogen feed line for feeding hydrogen to the fuel cell assembly,
a pressure reducer in the hydrogen feed line,
a high-pressure hydrogen reservoir,
a hydrogen line for feeding hydrogen from the high-pressure hydrogen reservoir into a hydrogen supply line for the fuel cell assembly, which connects the hydrogen line and the hydrogen feed line with each other,
a pressure reducer in the hydrogen line for reducing the hydrogen pressure,
a 3/2-way valve in the hydrogen line downstream of the pressure reducer or in the hydrogen supply line, and
a hydrogen pressure relief line connected to the 3/2-way valve,
wherein the 3/2-way valve, in a first switching position, allows the flow of gas from the high-pressure hydrogen reservoir into the hydrogen supply line, and in a second switching position, allows the flow of gas from the hydrogen supply line into the hydrogen pressure relief line;
characterized in that feeding of hydrogen from the hydrogen line into the hydrogen supply line is terminated and immediately thereafter the 3/2-way valve is switched from the first switching position to the second switching position.

### Claim 28 (depends on 27)

The method of claim 27, characterized in that the termination of feeding hydrogen into the hydrogen supply line and the switching of the 3/2-way valve from the first switching position to the second switching position is triggered by disconnection of an electrical load from the fuel cell system or by detection of an emergency situation.

### Claim 29

A method of activating and deactivating a fuel cell system comprising:
providing a fuel cell system comprising
a fuel cell assembly,
a hydrogen feed line for feeding hydrogen to the fuel cell assembly,
a pressure reducer in the hydrogen feed line,
a high-pressure hydrogen reservoir,
a hydrogen line for feeding hydrogen from the high-pressure hydrogen reservoir into a hydrogen supply line for the fuel cell assembly, which connects the hydrogen line and the hydrogen feed line with each other,
a pressure reducer in the hydrogen line for reducing the hydrogen pressure,
a 3/2-way valve in the hydrogen line downstream of the pressure reducer or in the hydrogen supply line, and
a hydrogen pressure relief line connected to the 3/2-way valve,
wherein the 3/2-way valve, in a first switching position, allows the flow of gas from the high-pressure hydrogen reservoir into the hydrogen supply line, and in a second switching position, allows the flow of gas from the hydrogen supply line into the hydrogen pressure relief line;
characterized in that feeding of hydrogen from the hydrogen line into the hydrogen supply line is terminated and immediately thereafter the 3/2-way valve is switched from the first switching position to the second switching position; and,
characterized in that hydrogen is provided for being fed from the hydrogen line into the hydrogen supply line, and thereafter the 3/2-way valve is switched from the second switching position to the first switching position.

### Claim 30

Use of a 3/2-way valve for pressure-relieving the hydrogen supply line and, optionally, part of the hydrogen feed line of a fuel cell system, comprising:
providing a fuel cell system comprising
a fuel cell assembly,
a hydrogen feed line for feeding hydrogen to the fuel cell assembly,
a pressure reducer in the hydrogen feed line,
a high-pressure hydrogen reservoir,
a hydrogen line for feeding hydrogen from the high-pressure hydrogen reservoir into a hydrogen supply line for the fuel cell assembly, which connects the hydrogen line and the hydrogen feed line with each other,
a pressure reducer in the hydrogen line for reducing the hydrogen pressure,
a 3/2-way valve in the hydrogen line downstream of the pressure reducer or in the hydrogen supply line, and
a hydrogen pressure relief line connected to the 3/2-way valve,
wherein the 3/2-way valve, in a first switching position, allows the flow of gas from the high-pressure hydrogen reservoir into the hydrogen supply line, and in a second switching position, allows the flow of gas from the hydrogen supply line into the hydrogen pressure relief line;
wherein switching of the 3/2-way valve from the first switching position to the second switching position causes hydrogen to be released from the hydrogen supply line and, optionally, from said part of the hydrogen feed line into the atmosphere.

### Claim 31 (depends on 30)

The use of claim 30, wherein the opening cross-section of the 3/2-way valve is dimensioned small enough that always only so small amounts of hydrogen can escape that the lower explosive limit of hydrogen in air is not reached at the outlet of the hydrogen pressure relief line.

### Claim 32

A motor vehicle comprising:
a fuel cell system comprising
a fuel cell assembly,
a hydrogen feed line for feeding hydrogen to the fuel cell assembly,
a pressure reducer in the hydrogen feed line,
a high-pressure hydrogen reservoir,
a hydrogen line for feeding hydrogen from the high-pressure hydrogen reservoir into a hydrogen supply line for the fuel cell assembly, which connects the hydrogen line and the hydrogen feed line with each other,
a pressure reducer in the hydrogen line for reducing the hydrogen pressure,
a 3/2-way valve in the hydrogen line downstream of the pressure reducer or in the hydrogen supply line, and
a hydrogen pressure relief line connected to the 3/2-way valve,
wherein the 3/2-way valve, in a first switching position, allows the flow of gas from the high-pressure hydrogen reservoir into the hydrogen supply line, and in a second switching position, allows the flow of gas from the hydrogen supply line into the hydrogen pressure relief line; or
a tank module that supplies the fuel cell assembly with hydrogen, the tank module comprising
a high-pressure hydrogen reservoir,
a hydrogen line for feeding hydrogen from the high-pressure reservoir into a hydrogen supply line for the fuel cell assembly,
a pressure reducer in the hydrogen line for reducing the hydrogen pressure,
a 3/2-way valve in the hydrogen line downstream of the pressure reducer, and
a hydrogen pressure relief line connected to the 3/2-way valve,
wherein the 3/2-way valve, in a first switching position, permits the flow of gas from the high-pressure hydrogen reservoir into the hydrogen supply line, and in a second switching position, permits the flow of gas from the hydrogen supply line into the hydrogen pressure relief line.