KR20190130823A - Fuel cell system using hydrogen storage alloy - Google Patents

Abstract

According to the present invention, a fuel cell system can supply hydrogen gas with the low content of carbon monoxide as a raw material to a fuel cell as the hydrogen gas passes through a purification unit using hydrogen storage alloy, thereby preventing degradation of electrode activity cause by carbon monoxide. In addition, the fuel cell system is miniaturized and becomes light to minimize the amount of emission gas, thereby being useful for supplying power in sealed conditions such as a submarine or the like.

Description

Fuel cell system using hydrogen storage alloy {FUEL CELL SYSTEM USING HYDROGEN STORAGE ALLOY}

The present invention relates to a fuel cell system. More specifically, the present invention relates to a fuel cell system used to supply power in closed conditions such as submarines.

In general, a fuel cell is a power generation device that converts chemical energy of hydrogen and oxygen in air directly into electrical energy. Such fuel cells are alkaline fuel cells (FCCs), phosphoric acid fuel cells (PAFCs), molten carbonate fuel cells (MCFCs), depending on the type of electrolyte used. It may be classified into a polymer electrolyte fuel cell (PEMFC).

Among these, the polymer electrolyte fuel cell (PEMFC) is also called a hydrogen ion exchange membrane fuel cell (Photon Exchange Membrane Fuel Cell) in that it uses hydrogen gas as a direct fuel, and can operate at a relatively low temperature compared to other fuel cells. Since the density is large, it has the advantage that it can be miniaturized and lightweight. However, in order to commercialize a polymer electrolyte fuel cell (PEMFC), a stable supply of hydrogen is the most important technical problem to be preempted.

As an alternative to this technical problem, a direct methanol fuel cell (DMFC) is known which uses methanol instead of hydrogen directly as a fuel (see Korean Patent Publication No. 2007-0036502). As another alternative, ethanol, methanol, liquefied petroleum gas (LPG), gasoline, etc. may be used to generate hydrogen gas through a reformer and use it in a fuel cell. There is a problem that carbon dioxide and carbon monoxide are included together.

Since carbon monoxide is a major cause of deterioration of electrode activity in a fuel cell, it is necessary to reduce the carbon monoxide content in hydrogen gas to about 10 ppm or less before being used as fuel of a fuel cell. In particular, fuel cells are also mounted in diesel submarines that must be stealthily underwater because air is not needed for combustion. Fuel cells used in such submarines are required to further reduce the content of carbon monoxide in hydrogen gas.

In addition, when the fuel cell is used in a submarine, a large amount of exhaust gas may increase the probability that the submarine is detected, and in order to discharge gas from the submarine to the outside, additional power to increase the pressure of the exhaust gas depending on the depth of submersion is required. As necessary, it is necessary to minimize the amount of exhaust gas.

Korean Unexamined Patent Publication No. 2007-0036502

Accordingly, an object of the present invention is to provide a fuel cell system capable of miniaturization and light weight, while supplying hydrogen gas having a low carbon monoxide content as a raw material, and minimizing the amount of exhaust gas.

According to the above object, the present invention provides a hydrogen supply unit for supplying hydrogen gas; An oxygen storage unit for supplying oxygen gas; A fuel cell unit including a fuel cell stack and connected to the hydrogen supply unit and the oxygen storage unit to generate electric energy by receiving hydrogen gas and oxygen gas; And a refining unit positioned between the hydrogen supply unit and the fuel cell unit, wherein the refining unit absorbs hydrogen gas supplied from the hydrogen supply unit, including a hydrogen storage alloy, to the hydrogen storage alloy and discharges it to the fuel cell unit. And a first hydrogen storage unit and a second hydrogen storage unit, wherein the first hydrogen storage unit and the second hydrogen storage unit are connected to each other in parallel to alternately perform absorption and discharge of hydrogen gas. do.

The fuel cell system according to the present invention can supply hydrogen gas having a low content of carbon monoxide as a raw material to the fuel cell while the hydrogen gas passes through the refining unit, thereby preventing deterioration of electrode activity by carbon monoxide. In addition, the fuel cell system is equipped with a reforming unit using methanol and water as a raw material can be miniaturized and lightweight, while minimizing the amount of exhaust gas by burning the gas not absorbed in the hydrogen storage unit to recycle heat to the reformer. can do. Therefore, the fuel cell system may be usefully used as a fuel cell system for supplying electric power in a closed condition such as a submarine.

1 schematically illustrates a configuration of a fuel cell system according to an embodiment of the present invention.
2A and 2B schematically illustrate the operating principle of a fuel cell system according to an embodiment.
3a and 3b schematically show the configuration and operation principle of a multi-stage fuel cell stack.

Hereinafter, with reference to the accompanying drawings will be described in detail the configuration and operation according to the embodiment of the present invention. The following description is one of several aspects of the invention that can be claimed, and the following description may form part of the detailed description of the invention.

However, in describing the present invention, a detailed description of known configurations or functions may be omitted to clarify the present invention.

As the invention allows for various changes and numerous embodiments, particular embodiments will be illustrated in the drawings and described in detail. However, this is not intended to limit the present invention to specific embodiments, it should be understood to include all changes, equivalents, and substitutes included in the spirit and scope of the present invention.

Terms including ordinal numbers such as first and second may be used to describe various components, but the components are not limited by such terms. These terms are only used to distinguish one component from another.

When a component is referred to as being 'connected' to another component, it is to be understood that there may be a direct connection to the other component, but other components may exist in between.

In addition, when a component is referred to as 'supplying' a particular substance to another component, it is understood that there is a supply line capable of supplying the substance to the other component to supply the substance through the supply line. Can be.

The terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting of the present invention. Singular expressions include plural expressions unless the context clearly indicates otherwise.

FIG. 1 schematically shows the configuration of a fuel cell system according to an embodiment of the present invention (in FIG. 1, squares indicate each component, solid arrows indicate raw material flow, and particularly thick solid arrows indicate hydrogen gas). Dashed arrows indicate heat flow).

Referring to FIG. 1, a fuel cell system according to an embodiment of the present invention includes a hydrogen supply unit 100 supplying hydrogen gas; An oxygen storage unit 200 for supplying oxygen gas; A fuel cell unit 500 including a fuel cell stack 510 and connected to the hydrogen supply unit 100 and the oxygen storage unit 200 to receive hydrogen gas and oxygen gas to generate electrical energy; And a purification unit 300 positioned between the hydrogen supply unit 100 and the fuel cell unit 500, and the purification unit 300 is supplied from the hydrogen supply unit 100 including a hydrogen storage alloy. And a first hydrogen storage unit 310 and a second hydrogen storage unit 320 for absorbing the hydrogen gas into the hydrogen storage alloy and discharging the hydrogen gas to the fuel cell unit 500. 310 and the second hydrogen storage unit 320 are connected to each other in parallel to alternately absorb and release hydrogen gas.

Hydrogen supply

The hydrogen supply unit 100 is a water storage unit 110 for supplying water; Methanol storage unit 120 for supplying methanol; And a reforming unit 150 connected to the water storage unit 110 and the methanol storage unit 120 to generate reformed hydrogen gas from water and methanol.

The reforming unit 150 vaporizes the water supplied from the water storage unit 110 and the methanol supplied from the methanol storage unit 120 by heating to approximately 250 to 300 ° C., and then vaporizes the catalyst of vaporized methanol and water vapor. The reaction may generate a reformed gas in which H ₂ , CO, CO _2, and the like are mixed. If necessary, a water-gas shift reactor may be provided to be involved in gas generation.

Specifically, in the reforming unit 150, methanol is converted to hydrogen, carbon monoxide, formaldehyde or methyl formate on a catalyst, and a reforming reaction occurs in the presence of water to be converted into hydrogen, carbon monoxide or carbon dioxide (below) See Scheme).

CH ₃ OH-> HCHO + H ₂

HCHO + CH ₃ OH-> H ₂ (OH) OCH _3- > HCOOCH ₃ + H ₂

HCOOCH _3- > CO + CH ₃ OH (or CO ₂ + CH ₄ )

Since the gas finally discharged from the hydrogen supply unit 100 through the reaction in the reforming unit 150 contains another type of gas other than hydrogen, the purity of the hydrogen gas in the subsequent purification unit 300 is increased and The gas content must be lowered.

In particular, since the carbon monoxide contained in the hydrogen gas is the main cause of lowering the electrode activity in the fuel cell, it is necessary to reduce the subsequent purification unit 300.

Purification Department

The purification unit 300 is located between the hydrogen supply unit 100 and the fuel cell unit 500.

The purification unit 300, including a hydrogen storage alloy, absorbs the hydrogen gas supplied from the hydrogen supply unit 100 to the hydrogen storage alloy and discharges the hydrogen gas to the fuel cell unit 500. ) And a second hydrogen storage unit 320.

Hydrogen storage alloys are alloys that can absorb hydrogen in a special state such as high pressure or low temperature to form metal hydride, and then release hydrogen by pressure or heat change to return to its original state. Hydrogen atoms penetrate into small spaces between the metal atoms that make up the hydrogen storage alloy. Rare earth metals (lanthanum, titanium, magnesium, etc.) that absorb hydrogen well and bind strongly, and transition metals that do not absorb hydrogen well (iron) , Nickel and the like) are appropriately combined to produce a hydrogen storage alloy that absorbs and releases hydrogen. Examples of the hydrogen storage alloy include an alloy of Mg ₂ Ni-based, FeTi-based, ZrMn ₂ -based, and LaNi ₅ based.

The gas supplied to the first hydrogen storage unit 310 and the second hydrogen storage unit 320 through the reaction in the reforming unit 150 in the hydrogen supply unit 100 contains carbon monoxide and carbon dioxide in addition to hydrogen gas. Since the first hydrogen storage unit 310 and the second hydrogen storage unit 320 absorb only hydrogen by a hydrogen storage alloy, hydrogen gas having high purity can be discharged to the fuel cell unit 500 thereafter. have.

In particular, since the hydrogen storage alloys of the first hydrogen storage unit 310 and the second hydrogen storage unit 320 do not absorb carbon monoxide gas, the hydrogen gas released after the absorption may have a very low carbon monoxide content.

For example, the hydrogen gas discharged from the first hydrogen storage 310 and the second hydrogen storage 320 may have a carbon monoxide content of 10 ppm or less. In addition, the hydrogen gas discharged from the first hydrogen storage 310 and the second hydrogen storage 320 may have a purity of 99.99% or more. More specifically, the hydrogen gas discharged from the first hydrogen storage unit and the second hydrogen storage unit may have a carbon monoxide content of 1 ppm or less and a purity of 99.999% or more.

Meanwhile, the hydrogen storage alloys of the first hydrogen storage unit 310 and the second hydrogen storage unit 320 require a predetermined time for absorbing and releasing hydrogen, respectively.

Accordingly, the first hydrogen storage unit 310 and the second hydrogen storage unit 320 are connected to each other in parallel to alternately absorb and release hydrogen gas.

In detail, the first hydrogen storage unit 310 and the second hydrogen storage unit 320 are operated at the same time, while the first hydrogen storage unit 310 and the second hydrogen storage unit 320 are connected to the hydrogen supply unit 100. The first mode (or hydrogen absorption mode) in which hydrogen supplied from is absorbed and the second mode (or hydrogen release mode) in which absorbed hydrogen is released are configured to operate alternately. For example, the first mode of the first hydrogen storage unit 310 and the second mode of the second hydrogen storage unit 320 may occur simultaneously, and the second mode and the second mode of the first hydrogen storage unit 310 may occur. The first mode of hydrogen storage 320 may occur simultaneously.

2A and 2B schematically illustrate the operating principle of a fuel cell system according to an embodiment (in Figs. 2A and 2B, thick arrows indicate hydrogen gas flow, white valves indicate open valves, and black valves). Represents a closed valve).

In detail, the first hydrogen storage unit 310 may receive hydrogen gas from the hydrogen supply unit 100 through a supply line provided with the first valve 301. At this time, when the first hydrogen storage unit 310 is operated in the first mode, the first valve 301 is opened to supply hydrogen to the first hydrogen storage unit 310 through the supply line, thereby storing the first hydrogen. Hydrogen may be absorbed inside the portion 310. In this case, carbon monoxide, carbon dioxide, and the like other than hydrogen may be passed through the first hydrogen storage 310 without being absorbed in the gas supplied from the hydrogen supply unit 100. In addition, when excess hydrogen is supplied, a portion of the first hydrogen storage unit 310 may pass through without being absorbed. As such, the gas that is not absorbed by the first hydrogen storage unit 310 may be recycled to the heat supply unit 400. On the contrary, when the first hydrogen storage unit 310 is operated in the second mode, hydrogen absorbed inside the first hydrogen storage unit 210 may be gradually released to the fuel cell unit 300.

Similarly, the second hydrogen storage unit 320 may receive hydrogen gas from the hydrogen supply unit 100 through a supply line provided with the second valve 302. At this time, when the second hydrogen storage unit 320 is operated in the first mode, the second valve 302 is opened to supply hydrogen to the second hydrogen storage unit 320 through the supply line, thereby storing the second hydrogen. Hydrogen may be absorbed in the portion 320. In this case, carbon monoxide, carbon dioxide, and the like other than hydrogen may be passed through the second hydrogen storage unit 320 without being absorbed in the gas supplied from the hydrogen supply unit 100. In addition, when excess hydrogen is supplied, part of the second hydrogen storage unit 320 may pass through without being absorbed. As such, the gas that is not absorbed in the second hydrogen storage unit 320 may be recycled to the heat supply unit 400. On the contrary, when the second hydrogen storage unit 320 is operated in the second mode, hydrogen absorbed in the second hydrogen storage unit 220 may be gradually released to the fuel cell unit 300.

Meanwhile, in the present exemplary embodiment, the case in which the purification unit 300 includes two hydrogen storage units, for example, the first hydrogen storage unit 310 and the second hydrogen storage unit 320, has been described. It is not limited to this. For example, in consideration of the operating time of the fuel cell unit 500, the purification unit 300 may be configured of three or more hydrogen storage units connected in parallel.

In addition, although not shown, in order to determine the time when the hydrogen supply unit 100 supplies hydrogen to the first hydrogen storage unit 310 or the second hydrogen storage unit 320, the first hydrogen storage unit 310 and the first Inside the hydrogen storage unit 220 may be a hydrogen residual sensor and a temperature sensor.

The hydrogen remaining amount sensor may detect the remaining amount of hydrogen in the first hydrogen storage unit 310 and the second hydrogen storage unit 320 and transmit the detected hydrogen remaining amount to the controller in real time. In addition, the temperature sensor may sense the internal temperatures of the first hydrogen storage unit 310 and the second hydrogen storage unit 320 and transmit the detected temperature to the controller in real time. Accordingly, the controller controls the first hydrogen storage unit 310 and the second hydrogen storage unit from the hydrogen supply unit 100 based on the remaining hydrogen and the internal temperature of the first hydrogen storage unit 310 and the second hydrogen storage unit 320. When hydrogen is supplied to the hydrogen storage unit 320 and when the hydrogen absorbed by the first hydrogen storage unit 310 and the second hydrogen storage unit 320 is discharged to the fuel cell unit 500 may be determined.

Fuel cell

The fuel cell unit 500 includes a fuel cell stack 510 and is connected to the hydrogen supply unit 100 and the oxygen storage unit 200 to receive hydrogen gas and oxygen gas to generate electrical energy.

The fuel cell stack may be a stack of a polymer electrolyte fuel cell (PEMFC).

For example, the fuel cell stack may have a structure in which a plurality of fuel cell cells including an anode electrode, a cathode electrode facing the anode electrode, and an electrolyte membrane interposed between the anode electrode and the cathode electrode are stacked.

In detail, the anode electrode may use hydrogen supplied from the hydrogen supply unit 100, and the cathode electrode may use oxygen supplied from the oxygen storage unit 200. At this time, an oxidation reaction such as the following Equation (1) occurs at the anode, and a reduction reaction such as the following Equation (2) occurs at the cathode. In addition, the total reaction of the fuel cell unit 500 is as shown in Equation (3) below.

^{_{H 2 → 2 H + + 2e}} - (1)

^{_{1/2 O 2 + 2 H + +}} 2e - → H 2 O (2)

H ₂ + 1/2 O ₂ → H ₂ O (3)

As an example, the fuel cell stack 510 may be configured in one stage. In this case, when the first 100% hydrogen gas and oxygen gas are supplied, after generating electrical energy in the fuel cell stack, approximately 10-20% of the hydrogen gas and oxygen gas may be unused and released. Such unused gas is not preferable because it requires a separate process to be discharged in a closed space such as a submarine. Therefore, by recycling the unused gas in the fuel cell stack to the heat supply unit, it is possible to minimize the amount of exhaust gas even when using the fuel cell stack of the first stage.

As another example, the fuel cell stack 510 may be a multi-stage fuel cell stack. This multi-stage fuel cell stack is suitable for confined spaces, such as submarines, because the amount of gas released is minimized. Specifically, the multi-stage fuel cell stack 510 may be a fuel cell stack of two to ten stages, in which unused hydrogen gas may be discharged in an amount of 0.5% or less of the supplied hydrogen gas.

3a and 3b schematically show the configuration and operation principle of a multi-stage fuel cell stack.

Referring to FIG. 3A, in the fuel cell stack 510, a plurality of fuel cell stacks 511, 512, and 513 may be connected in series to improve a consumption rate. At this time, the first 100% of fuel (hydrogen gas and oxygen gas) is supplied to the first fuel cell stack 511 to generate electrical energy, and then releases 10 to 20% of unused fuel, and the unused fuel is the second fuel cell. After supplying the stack 512 to generate the electrical energy and discharge the unused fuel of 1 ~ 4% compared to the first, after the unused fuel is supplied to the third fuel cell stack 513 to generate the electrical energy Less than 0.5% of unused fuel can be emitted.

Referring to FIG. 3B, according to another specific example, the fuel cell stack 510 may improve consumption rate through a plurality of reactions in one fuel cell stack 510. At this time, the first 100% of fuel (hydrogen gas and oxygen gas) is supplied to the fuel cell stack 510, generates electrical energy in one step, and then releases 20-40% of unused fuel compared to the first, and then supplies electricity in two steps. After generating energy, it releases 5 ~ 15% of unused fuel compared to the first time, and generates electric energy in 3 stages, then releases 1 ~ 5% of unused fuel compared to the first time, and generates electric energy in 4 stages Less than 0.5% of unused fuel can be released.

Oxygen storage

The oxygen storage unit 200 stores therein oxygen for supplying to a cathode (oxygen electrode) of the fuel cell stack 510.

The oxygen storage unit 200 may include a tank for storing liquid oxygen. Under normal conditions, oxygen in the atmosphere can be used as an oxygen source of a fuel cell, but it is preferable to use liquid oxygen because the atmosphere cannot be used under closed conditions such as a submarine.

Heat supply

In addition, the fuel cell system is connected to the methanol storage unit 120 and the oxygen storage unit 200, and adds a heat supply unit 400 for supplying heat to the reforming unit 150 by burning methanol and oxygen gas. It can be included as.

In addition, the heat supply unit 400, the first hydrogen storage unit 310, and the second hydrogen storage unit 320 are connected to each other to form the first hydrogen storage unit 310 and the second hydrogen storage unit 320. Gas not absorbed in the hydrogen storage alloy may be recycled to the heat supply unit 400.

Specifically, since the gas that is not absorbed by the first hydrogen storage unit 310 and the second hydrogen storage unit 320 includes hydrogen, carbon monoxide, and carbon dioxide gas, the gas is combusted by the heat supply unit 400 and the reforming unit ( 150 may be used to supply heat. As a result, the amount of gas finally discharged from the fuel cell system can be further reduced.

In addition, although not shown, the heat supply unit 400 and the fuel cell unit 500 may be connected to recycle unused gas from the fuel cell unit 500 to the heat supply unit 400. Specifically, since the unused gas in the fuel cell unit 500 includes hydrogen gas and oxygen gas, it may be burned in the heat supply unit 400 and used to supply heat to the reforming unit 150. As a result, the amount of gas finally discharged from the fuel cell system can be further reduced.

The heat supply unit 400 may include a burner and a heat exchanger. As an example, after the gases supplied to the heat supply unit 400 are combusted in a burner, heat may be supplied to the reformer 150 through a heat exchanger.

As another example, a combustion burner may be installed around the reforming unit 150 to directly supply combustion heat to the reforming unit 150. This approach has the advantage of miniaturization since no heat exchanger is required.

Incinerator

In addition, although not shown, the fuel cell system may further include an incineration part connected to the fuel cell part 500.

The incineration unit may incinerate unused hydrogen gas emitted from the fuel cell unit 500.

As a result, the amount of gas finally discharged from the fuel cell system can be further reduced.

Control

In addition, although not shown, the fuel cell system includes at least one of the hydrogen supply unit 100, the oxygen storage unit 200, the purification unit 300, the heat supply unit 400, the fuel cell unit 500, and the incineration unit. The control unit may further include a control unit.

The control unit may be, for example, a small built-in computer, and may include a data processing unit including a program, a memory, a CPU, and the like.

The program of the controller is based on the values measured or analyzed from the hydrogen supply unit 100, oxygen storage unit 200, purification unit 300, heat supply unit 400, fuel cell unit 500 and incineration unit. It may include an algorithm for controlling the operation. Such a program can be stored in a memory unit such as a computer storage medium such as a flexible disk, a compact disk, a hard disk, or a magneto-optical disk (MO), and can be installed in the controller.

Effects and uses

The fuel cell system according to the embodiments of the present invention can supply hydrogen gas having a low content of carbon monoxide as a raw material to the fuel cell while the hydrogen gas passes through the refining unit, thereby preventing deterioration of electrode activity by carbon monoxide.

In addition, the fuel cell system is equipped with a reforming unit using methanol and water as a raw material can be reduced in size and weight, while minimizing the amount of exhaust gas by the fuel cell stack, to supply power in a closed condition such as a submarine It can be usefully used as a fuel cell system.

Preferably, the fuel cell system according to the present invention can be used in submarines, and thus the fuel cell system can be a fuel cell system for submarines.

Although embodiments of the present invention have been described above with reference to the accompanying drawings, those skilled in the art to which the present invention pertains may implement the present invention in other specific forms without changing the technical spirit or essential features thereof. I can understand that. For example, those skilled in the art can change the material, size, etc. of each component according to the application field, or combine or replace the embodiments in a form that is not clearly disclosed in the embodiments of the present invention, this is also the present invention It will not go beyond the scope of the. Therefore, the above-described embodiments are to be considered in all respects as illustrative and not restrictive, and such modified embodiments should be included in the technical spirit described in the claims of the present invention.

100: hydrogen supply unit, 110: water storage unit,
120: methanol storage unit, 150: reforming unit,
200: oxygen storage unit, 300: purification unit,
301, first valve, 302: second valve,
310: first hydrogen storage, 320: second hydrogen storage,
400: heat supply unit, 500: fuel cell unit,
510: fuel cell stack, 511: first fuel cell stack,
512: second fuel cell stack, 513: third fuel cell stack.

Claims (9)

A hydrogen supply unit supplying hydrogen gas;
An oxygen storage unit for supplying oxygen gas;
A fuel cell unit including a fuel cell stack and connected to the hydrogen supply unit and the oxygen storage unit to generate electric energy by receiving hydrogen gas and oxygen gas; And
A purification unit positioned between the hydrogen supply unit and the fuel cell unit,
The purification unit includes a first hydrogen storage unit and a second hydrogen storage unit which absorb a hydrogen gas supplied from the hydrogen supply unit including a hydrogen storage alloy to the hydrogen storage alloy and discharge it to the fuel cell unit. And a hydrogen storage unit and the second hydrogen storage unit are connected in parallel with each other to alternately absorb and discharge hydrogen gas.
The method of claim 1,
And a hydrogen storage alloy of the first hydrogen storage portion and the second hydrogen storage portion does not absorb carbon monoxide gas.
The method of claim 1,
And a hydrogen gas discharged from the first hydrogen storage unit and the second hydrogen storage unit has a carbon monoxide content of 10 ppm or less.
The method of claim 3, wherein
And a hydrogen gas discharged from the first hydrogen storage unit and the second hydrogen storage unit has a purity of 99.99% or more.
The method of claim 1,
And the fuel cell stack is a multi-stage fuel cell stack.
The method of claim 1,
The hydrogen supply unit
A water storage unit for supplying water;
A methanol storage unit for supplying methanol; And
And a reforming unit connected to the water storage unit and the methanol storage unit to generate reformed hydrogen gas from water and methanol.
The method of claim 6,
The fuel cell system
And a heat supply unit connected to the methanol storage unit and the oxygen storage unit and supplying heat to the reforming unit by combusting methanol and oxygen gas.
The method of claim 7, wherein
The first hydrogen storage part and the second hydrogen storage part are connected to the heat supply part,
And a gas not absorbed by the hydrogen storage alloy of the first hydrogen storage unit and the second hydrogen storage unit to the heat supply unit.
The method of claim 1,
A fuel cell system, wherein the fuel cell system is used in a submarine.

Images