KR20100022362A - A fuel cell with insulated manifold - Google Patents

Abstract

PURPOSE: A fuel cell including insulated coolant manifold is provided to prevent the attach of a cation and an electron from cooling water flowing inside a fuel cell stack and to reduce manufacturing costs by simplifying the structure of the fuel cell. CONSTITUTION: A fuel cell including insulated coolant manifold comprises: a fuel cell stack(20) transferring electricity generated from a film-electrode assembly through a separator(24); a fuel supply device supplying reactive gas to the fuel cell stack; and a cooling device to absorb the heat generated from the fuel cell stack. The cooling device comprises the following: a cooling water tank; a pump supplying cooling water to the inside of the fuel cell stack; a cooling water manifold(72) with an electrically insulated inner part flowing the cooling water to the inside of the separator while connected to a cooling water pipe(70); an un-insulated cooling water channel(74) absorbing the heat from the separator while connected to the cooling water manifold; and a heat exchanger receiving the heat absorbed by the cooling water while installed on the cooling water pipe.

Description

A fuel cell with insulated manifold

The present invention relates to a fuel cell stack having an insulated cooling water manifold. The present invention relates to a fuel cell stack having an insulated coolant manifold that prevents adhesion of cations and electrons to the coolant that flows inside the fuel cell stack by insulating the branch pipe.

A fuel cell is an energy conversion device that converts chemical energy of a fuel directly into electrical energy by a chemical reaction. Unlike a general battery, a fuel cell generates electricity as long as fuel is supplied without recharging. As a power generation system, electric energy is obtained through an electrochemical reaction of hydrogen extracted from fuel such as natural gas / gasoline / methanol and oxygen supplied through air.

Such a fuel cell generally comprises a configuration including a fuel cell stack, a fuel supply device, and a cooling device as shown in FIG. 1. The fuel cell stack includes a membrane-electrode assembly as shown in FIG. The electricity generated from the membrane-electrode assembly is installed by installing a separator (also referred to as a biopolar plate) between a plurality of fuel cell cells configured in the form of MEA: Membrane-Electrode Assembly. It is transmitted through the separation plate, and end plates (end plates) are installed at both ends of the fuel cell stack to fasten the end plate or pressurize the air pressure so that all the components of the fuel cell stack are integrally fastened. Herein, the membrane-electrode assembly smoothly diffuses an anode (anode) through which hydrogen is supplied and is oxidized, a cathode (cathode) through which oxygen is reduced, and hydrogen / oxygen to each anode / reduction electrode. It is made of a configuration including a gas diffusion layer and an electrolyte membrane positioned between the anode and the reduction electrode.

In addition, the separator is in contact with the anode and the cathode of the neighboring fuel cell cells, each side of the separator is formed with a hydrogen channel for supplying hydrogen to the anode, the other side of the separator as a cathode An oxygen channel is formed for supplying oxygen. A device for supplying hydrogen and oxygen to the hydrogen channel and the oxygen channel of the separator is a fuel supply device.

On the other hand, the separation plate also receives the reaction heat generated during the oxidation-reduction reaction of hydrogen and oxygen, the cooling device is a device for cooling the separation plate in order to prevent the temperature rise of the fuel cell stack by the reaction heat.

As such, the fuel supply device is a device for supplying a reactor such as hydrogen / oxygen to the fuel cell stack. The fuel supply device supplies hydrogen to the fuel cell stack through a fuel tank, a pump and a reformer, and introduces a pump that introduces air from the outside. Oxygen is supplied to the fuel cell stack.

The cooling device is a device for absorbing heat generated from the fuel cell stack and includes a cooling water tank, a pump, a cooling water manifold, a cooling water channel, and a heat exchanger.

Here, the cooling water manifold is formed through each of the upper and lower ends of the plurality of separator plates constituting the fuel cell stack, and is connected to the cooling water pipe to allow the coolant to flow into and out of the separator plate. It is formed to traverse and communicates with the cooling water manifold, and receives the cooling water to absorb the heat transferred to the separator plate.

As a technology related to a fuel cell including a cooling device as described above, Republic of Korea Patent Publication No. 10-0599715 "Fuel cell system, stack, and separator", Registration No. 10-0820519 "Fuel cell stack cooling device ", Published Patent Publication No. 10-2004-0005139," Separation plate for fuel cell stack "and the like have been devised.

However, in the “fuel cell system, the stack, and the separator” and the “fuel cell stack cooling device”, the coolant manifold and the coolant channel formed inside the fuel cell stack are not electrically insulated, and move through the separator plate. Electrons were attached to the cooling water, or cations formed in the membrane-electrode assembly were attached to the cooling water.

As described above, when ions are attached to the coolant, electricity is generated to short-circuit the fuel cell stack, or electricity generated from the membrane-electrode assembly flows into the coolant and the power generation efficiency of the fuel cell is lowered. An ion eliminator for removal was installed in the cooling unit of the fuel cell. However, such an ion remover is installed on the cooling water duct in which the cooling water is circulated, and as the pressure of the circulating coolant decreases, the power of the pump has to be increased to circulate the cooling water at a predetermined flow rate. There was a problem of increased consumption.

In addition, the ion remover is provided with a filter for removing the ions from the cooling water, such a filter is a consumable that must be replaced at any time after a certain period of time, the cost and time required for maintenance work for the operation of the fuel cell. There was this.

In addition, the conventional fuel cell as described above has a limitation in miniaturizing the fuel cell as the ion remover must be additionally provided.

On the other hand, the "split plate for fuel cell stack" is a coating layer made of an insulating material on the inner surface of the coolant channel 74 formed in the separator as shown in (b) of FIG. A technique of forming and electrically insulating 742 is disclosed.

However, the separator plate where the coolant channel formed across the upper and lower portions of the separator is located is a region where electrons generated in the membrane-electrode assembly move, and the electrons move through the coolant channel. Since the potential difference does not occur on both sides of the coolant channel as formed in one separator plate, electrons are attached to the coolant in the coolant channel.

In fact, the current flow through the cooling water occurs in the cooling water manifold formed in the upper and lower portions of the separator. That is, as described above, both ends of the cooling water flow path flowing through the center of the separation plate have no potential difference, while a potential difference occurs between the separation plates disposed at both ends of the membrane electrode assembly and another separation plate, so that electrons or cations are used as cooling water between the separation plates. This sticking phenomenon occurred. Accordingly, electricity generation through the cooling water is generated, thereby reducing the power generation efficiency of the fuel cell, and ions in the cooling water are attached to the separator to form salts or cause corrosion.

As described above, the "split plate for fuel cell stack" had the same problem as the conventional fuel cell because it could not prevent the conduction phenomenon or prevent the ions from adhering to the cooling water passage.

Therefore, the present invention improves such a problem of the prior art, by insulating the cooling water manifolds formed at the upper and lower ends of the separator plate through which the potential difference actually occurs due to the structure of the fuel cell stack to allow the positive and negative electrons to flow into the cooling water. It is an object of the present invention to provide a fuel cell having a new type of insulated coolant manifold which can prevent the adhesion of cations and electrons to the coolant that flows through the inside.

According to a feature of the present invention for achieving the above object, by installing a separator between a plurality of fuel cells (cell) in the form of membrane-electrode assembly (MEA) (Meabrane-Electrode Assembly) (MEA) A fuel cell stack for allowing electricity generated from an electrode assembly to be transferred through the separator plate, a fuel supply device for supplying a reactant such as hydrogen / oxygen to the fuel cell stack, and heat generated from the fuel cell stack A fuel cell comprising a cooling device for absorbing water, the cooling device comprising: a cooling water tank in which cooling water is stored; A pump installed on the cooling water pipe formed between the cooling water tank and the fuel cell stack to allow the cooling water to be supplied into the fuel cell stack; A cooling water manifold formed through upper and lower ends of the plurality of separation plates constituting the fuel cell stack, connected to the cooling water pipe, and flowing coolant into and out of the separation plate, the inner surface of which is electrically insulated; A cooling water channel formed in the separator to cross the upper and lower portions of the separating plate, communicating with the cooling water manifold tube, receiving cooling water, absorbing heat transferred to the separating plate, and not being electrically insulated; The heat exchanger is installed on the cooling water pipe and receives heat from the cooling water absorbing heat through the cooling water channel.

In the fuel cell having the insulated coolant manifold according to the present invention, the inner surface of the coolant manifold is characterized in that it is any one selected from those coated with a liquid insulating material and those with a plasma surface treatment. .

According to the fuel cell having the insulated coolant manifold according to the present invention, the adhesion of cations and electrons to the coolant flowing through the fuel cell stack is prevented, thereby eliminating components such as an ion remover provided separately. The chiller can be configured. As a result, the configuration of the fuel cell can be simplified, and the fuel cell can be miniaturized while the manufacturing cost of the fuel cell is reduced. In addition, there is no need to use consumables such as filters to remove ions, thereby reducing the maintenance cost of the fuel cell.

In addition, since the pressure drop of the ion remover does not occur during the operation of the pump for circulating the coolant during the operation of the fuel cell, the power consumption of the pump is reduced, thereby reducing the operating cost.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to FIGS. 3 and 5. On the other hand, in the drawings and detailed description showing and referring to the configuration and operation easily understood by those skilled in the art from a fuel cell having a common insulated coolant manifold, or omitted. In particular, in the drawings and detailed description of the drawings, detailed descriptions and illustrations of specific technical configurations and operations of elements not directly related to technical features of the present invention are omitted, and only the technical configurations related to the present invention are briefly shown or described. It was.

3 is a block diagram showing a fuel cell according to a preferred embodiment of the present invention, Figure 4 (a) is a view showing the configuration of a fuel cell stack of a fuel cell according to a preferred embodiment of the present invention; 4B is a view illustrating a state in which the coolant manifold is electrically insulated in a fuel cell stack forming a fuel cell according to an exemplary embodiment of the present invention, and FIG. 5 is a preferred embodiment of the present invention. Cross-sectional view of a separator plate electrically insulating the coolant manifold in the fuel cell stack constituting the fuel cell according to the present invention.

A fuel cell having an insulated coolant manifold according to the present invention has a structure including a plurality of fuel cells and a separator configured in the form of a membrane-electrode assembly (MEA). The fuel cell stack is characterized in that the cooling water manifold which is in communication with the cooling water channels formed in each of the separator plates to inject and cool the cooling water is insulated.

Such a fuel cell having an insulated coolant manifold according to the present invention differs from the prior art insulated from a coolant channel formed inside a separator plate in which a potential difference does not occur. By insulating the cooling water manifolds formed at the upper and lower ends of the separator plate through which the cations and the electrons are introduced, cations and electrons are prevented from adhering to the cooling water flowing in the fuel cell stack.

Accordingly, it is possible to configure the cooling device of the fuel cell without a component such as an ion remover separately provided, which simplifies the configuration of the fuel cell and eliminates the use of consumables such as a filter for removing ions. In addition, the pressure drop of the ion eliminator does not occur, thereby reducing the power consumption during the pump operation for cooling water circulation.

The fuel cell 100 having the insulated coolant manifold according to the preferred embodiment of the present invention includes a fuel cell stack 20, a fuel supply device 40, and a cooling device 60 as shown in FIG. 3.

The fuel cell stack 20 includes a plurality of membrane-electrode assemblies 22 having a configuration including an anode electrode / reduction electrode / electrolyte membrane as shown in FIG. 4A, and hydrogen / oxygen oxide / reduction electrode. Gas diffusion layers 222 and 224 and the plurality of separators 24 provided between the membrane-electrode assembly 22 and upper and lower ends of the membrane-electrode assembly 22 to be diffused smoothly. -Installed to be in contact with the gasket 28 and the separators 24 located at both ends of the fuel cell stack 20 to prevent the reactor body such as hydrogen and oxygen supplied to the electrode assembly 22 from leaking to the outside. And the current collector plate 30 which integrates electricity generated from the fuel cell stack 20 to be supplied to the outside, and is installed at both ends of the fuel cell stack 20 and fastened to each other to form the fuel cell stack 20. The end plate 26 to fasten the components integrally It consists of a configuration that includes.

Here, electricity generated from the membrane-electrode assembly 22 is transferred through the separator 24.

The fuel supply device 40 is a device for supplying a reactant such as hydrogen / oxygen to the fuel cell stack 20, and includes a fuel tank 42 and a fuel tank 42 in which fuel such as natural gas / gasoline / methanol is stored. A pump 44 for discharging fuel from the fuel cell, a reformer 46 for extracting hydrogen gas from a fuel such as natural gas / gasoline / methanol, and hydrogen gas extracted from the reformer 46. Hydrogen is transferred to the membrane-electrode assembly 22 through the hydrogen gas pipe 50 which is supplied to the hydrogen channel 242 formed in the separator 24. At the same time, the fuel supply device 40 supplies a pump 48 that sucks outside air and air that includes oxygen sucked from the pump 48 to an oxygen channel 244 formed in the separator 24. Oxygen is transferred to the membrane-electrode assembly 22 through the gas pipe 52.

The cooling device 60 is a device for absorbing heat generated from the fuel cell stack 20. The cooling device 60 according to a preferred embodiment of the present invention includes a coolant tank 62, a pump 64, and a coolant. It consists of a branch pipe 72, a coolant channel 74, and a heat exchanger 68.

The coolant tank 62 is a container in which the coolant is stored, and the pump 64 is installed on the coolant pipe line 70 formed between the coolant tank 62 and the fuel cell stack 20 so that the coolant is in the fuel cell stack 20. To be fed into the.

Cooling water manifold 72 is formed by passing through the upper and lower ends of the plurality of separation plates 24 constituting the fuel cell stack 20, the holes having a predetermined size formed in the upper and lower ends of the separation plate 24, respectively. (24) are connected to each other while communicating with each other to form a single pipeline. The cooling water manifold 72 is connected to the cooling water pipe 70 and the cooling water channel 74 to introduce the cooling water into the separator plate 24 or discharge the cooling water in the separator plate 24 to the outside.

Here, the cooling water manifold 72 according to the present invention is formed with a coating layer 722 made of an insulating material on the inner surface as shown in Figure 4 (b) and Figure 5 to electrically insulate the cooling water manifold 72 By the treatment, electrons and cations are prevented from adhering to the cooling water flowing through the cooling water manifold 72.

Teflon is preferably used as the insulating material forming the coating layer 722. Teflon has excellent electrical insulation properties and is a chemically very stable polymer compound having excellent chemical inertness, heat resistance, and non-tackiness. This is because the cooling water manifold 72 is prevented from being corroded by hydrogen, oxygen or ions supplied to the fuel cell stack 20.

In this way, the coolant manifold 72 is preferably insulated by an insulating material having electrical insulation and corrosion resistance.

On the other hand, the coating layer 722 on the inner surface of the coolant manifold 72 is assembled to the coolant manifold 72 in which the liquid insulating material is formed inside the separator 24 before assembling and integrally coupling the fuel cell stack 20. The coating plate may be formed, or may be formed by dipping a portion of the separator plate 24 in which the cooling water manifold 72 is formed in a container in which a predetermined amount of the insulating material is contained in the liquid phase. When the coating layer 722 is permanently attached to the inner surface of the cooling water manifold 72, the insulating material is plasma-treated.

The coolant channel 74 is formed to cross the upper and lower portions of the separator plate 24 in the separator plate 24. The coolant channel 74 communicates with the coolant manifold 72 to receive the coolant and to supply the coolant to the entire area of the separator plate 24. Flowing over will absorb heat transferred to the separator 24.

Here, the cooling water channel 74 according to the present invention is not electrically insulated unlike the Patent Publication No. 10-2004-0005139 "dividing plate for the fuel cell stack".

As described above, the fuel cell 100 according to the present invention is electrically insulated only in the coolant manifold 72 and does not have a separate insulator in the coolant channel 74. In this case, electrons are attached to the coolant. This is because is generated in the cooling water manifold 72 formed in the upper and lower portions of the separation plate 24.

That is, the portion of the separator plate 24 where the coolant channel 74 formed across the upper and lower portions of the separator plate 24 is located is a portion to which electrons generated in the membrane-electrode assembly 22 move, and electrons are cooling water. The coolant channel 74 is moved through the channel 74. As the coolant channel 74 is formed in one separator 24, a potential difference does not occur on both sides of the coolant channel 74, so that the coolant channel 74 In this case, the phenomenon in which electrons adhere to the cooling water does not actually occur.

On the other hand, a potential difference is generated between the separator 24 adjacent to each other around the membrane electrode assembly 22 and another separator 24, so that electrons or cations adhere to the cooling water.

As described above, in the fuel cell 100 according to the present invention, as only the cooling water manifolds 72 formed at the upper and lower ends of the separator 24 are insulated, they cover the upper and lower portions of the separator 24 in a large area. Compared to insulating the cooling water channels 74 distributed over, the amount of work and cost of the insulated treatment are reduced.

In addition, unlike the conventional fuel cell 100 ′ as shown in FIG. 1, the fuel cell 100 according to the present invention can prevent the adhesion of ions to the cooling water, thereby eliminating the need for the ion remover 66. The fuel cell 100 can be miniaturized.

As described above, the fuel cell having the insulated coolant manifold according to the embodiment of the present invention is shown according to the above description and the drawings, but this is only an example and is not limited to the scope of the present invention. It will be apparent to those skilled in the art that various changes and modifications can be made therein.

1 is a block diagram showing an embodiment of a conventional fuel cell;

Figure 2 (a) is a view for showing the configuration of a fuel cell stack constituting a conventional fuel cell;

Figure 2 (b) is a view for showing a state in which the coolant channel is electrically insulated in the fuel cell stack constituting a conventional fuel cell;

3 is a block diagram for showing a fuel cell according to a preferred embodiment of the present invention;

4 (a) is a view showing the configuration of a fuel cell stack of a fuel cell according to a preferred embodiment of the present invention;

Figure 4 (b) is a view for showing a state in which the coolant manifold electrically insulated in the fuel cell stack constituting the fuel cell according to an embodiment of the present invention;

5 is a cross-sectional view of a separator plate electrically insulated from a coolant manifold in a fuel cell stack forming a fuel cell according to an exemplary embodiment of the present invention.

* Description of the symbols for the main parts of the drawings *

20 fuel cell stack 22 membrane-electrode assembly

222, 224: gas diffusion layer 24: separation plate

242: hydrogen channel 244: oxygen channel

26: end plate 28: gasket

30: current collector plate 40: fuel supply device

42: fuel tank 44, 48, 64: pump

46: reformer 50: tube for hydrogen gas

52: oxygen gas pipe 60: cooling device

62 coolant tank 66 deionizer

68 heat exchanger 70 coolant pipe

72: cooling water manifold 722, 742: coating layer

74: cooling water channel 100, 100 ': fuel cell

Claims (2)

Separator is installed between a plurality of fuel cell cells in the form of membrane-electrode assembly (MEA) to transfer electricity generated from the membrane-electrode assembly through the separator. A fuel cell comprising: a fuel cell stack; a fuel supply device for supplying a reactant such as hydrogen / oxygen to the fuel cell stack; and a cooling device for absorbing heat generated from the fuel cell stack. The cooling device includes a cooling water tank in which cooling water is stored; A pump installed on the cooling water pipe formed between the cooling water tank and the fuel cell stack to allow the cooling water to be supplied into the fuel cell stack; A cooling water manifold formed through upper and lower ends of the plurality of separation plates constituting the fuel cell stack, connected to the cooling water pipe, and flowing coolant into and out of the separation plate, the inner surface of which is electrically insulated; A cooling water channel formed in the separator to cross the upper and lower portions of the separating plate, communicating with the cooling water manifold tube, receiving cooling water, absorbing heat transferred to the separating plate, and not being electrically insulated; And a heat exchanger installed on the cooling water pipe and receiving heat from the cooling water absorbing heat through the cooling water channel. The method of claim 1, The inner surface of the coolant manifold is a fuel cell having an insulated coolant manifold, characterized in that any one selected from a liquid insulating material is applied and the insulating material is plasma surface treatment.

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