KR20060004269A - Humidifier integrated fuel cell separator - Google Patents

Abstract

The present invention relates to a fuel cell separator plate integrated with a humidifier, and in particular, the fuel cell unit and the membrane humidifier are formed in one separator plate, so that a separate external humidifier is not required for humidifying the reactor body, Since the membrane humidifying unit is also unnecessary, the humidifier unit integrated fuel cell separation plate capable of reducing the space and weight occupied by an external humidifier or a separate membrane humidifying unit, reducing the associated cost and volume, and increasing the heat recovery rate.

Description

Humidifying unit integrated fuel cell separator {Separator including humidifying plate for fuel cell}

1 is a schematic view showing a separator of a conventional fuel cell stack.

Figure 2 is a schematic diagram showing that the humidifier is installed on the separator of Figure 1;

Figure 3 is a schematic diagram showing another conventional humidifier for fuel cells.

Figure 4 is a schematic view showing a humidifying unit integrated fuel cell separator in accordance with a preferred embodiment of the present invention.

<Explanation of symbols for the main parts of the drawings>

100: separator 110: fuel cell unit

130: membrane humidifier 150: humidification membrane

170: dividing wall 200: oxidizing gas flow path

300: oxidant outlet 350: oxidant inlet

400: fuel gas outlet 450: fuel gas inlet

500: cooling water inlet 550: cooling water outlet

The present invention relates to a humidifying unit integrated fuel cell separator, and more particularly, to a humidifying unit integrated fuel cell separator in which a fuel cell unit and a membrane humidifying unit are formed together in one separator.

In general, a fuel cell is a energy converter that converts chemical energy into electrical energy by an electrochemical reaction between hydrogen as a fuel and oxygen in the air as an oxidant. Fuel cells are classified into alkali type (AFC), phosphoric acid type (PAFC), molten carbonate (MCFC), solid oxide (SOFC) and polymer electrolyte fuel cell (PEMFC) according to the operating temperature and the type of electrolyte. Among these fuel cells, polymer electrolyte fuel cells (PEMFCs) use polymers as electrolytes, and thus, there is no risk of corrosion or electrolyte evaporation due to electrolytes, and high current density is obtained per unit area. Compared with other fuel cells, the output characteristics are much higher, the operating temperature is lower, as well as fast start-up and response characteristics. The membrane-electrode assembly (MEA) for PEMFC is formed by bonding an electrode composed of a catalyst and a gas diffusion layer and an ion conductive polymer electrolyte membrane. Since the electrolyte membrane of the polymer electrolyte fuel cell must contain a certain amount of water to increase the ion conductivity and increase the output, an external humidifier or a membrane humidifier can be used to supply the reactors with 70 to 90 degrees of heat and 80% relative humidity. Consists of.

The separator (or bipolar plate) of the fuel cell supplies humidified reactants to the MEA of the PEMFC, drains the water generated, and transports electrons generated during the electrochemical reaction from the anode to the cathode. Do it.                         

In general, a separator having such a role is manufactured by forming a cooling water flow path for controlling an operating temperature of a fuel cell stack between an anode side separator plate on which a fuel gas flow path is formed and a cathode side separator plate on which an oxidant gas flow path is formed, and combining the same. . Graphite or metal is typically used as a material of the separator.

On the other hand, as a structure of a fuel cell stack including a plurality of separator plates, it is shown in the publication of Korean Laid-Open Patent Publication No. 2003-0018078, shown in FIG. According to this publication, the fuel cell assembly has a structure in which unit cells for generating electricity are stacked, and each unit cell includes a gas diffusion layer, a separator plate, an electrode film, and the like. In addition, each unit cell is separately supplied with hydrogen, which is a fuel gas, oxygen, which is an oxidant, and cooling water for cooling, and a hydrogen and oxygen flow path having a groove shape through which hydrogen and oxygen can flow to the separator 25 is provided on one side and the same. It is formed in the other surface, and the cooling water flow path is formed in the inside. In FIG. 1, only one surface of the separator is illustrated, so only the hydrogen flow path 251a is illustrated. In this separation plate, inlet holes 253a, 253b and 253c and outlet holes 255a, 255b and 255c of hydrogen and oxygen and cooling water are formed. The fuel cell stack is formed by stacking these separators, and thus, hydrogen and oxygen of the stacked separators, the inlet holes 253a, 253b and 253c of the coolant and the outlet holes 255a, 255b and 255c. And inlet and outlet passages of oxygen and cooling water.

 In the fuel cell stack thus constructed, the humidification of hydrogen, which supplies moisture to hydrogen injected during operation, is essential to maintain the ion conductivity of the electrolyte membrane. To this end, as shown in FIG. 2, a plurality of fine passages 257 are formed between the coolant inlet hole 253c constituting the coolant inlet passage of the fuel cell assembly and the hydrogen inlet hole 253a constituting the hydrogen inlet passage. The coolant passing through the coolant inlet passage through the fine passage 257 can be sucked into the hydrogen inlet passage and sprayed.

On the other hand, as a humidifier for fuel cells, it is presented in the publication of Korean Laid-Open Patent Publication No. 2002-0032874. According to this publication, as shown in FIG. 3, a hydrogen flow path is formed on an inner side surface to supply hydrogen, and an air flow path is formed on an inner side surface to supply air. A third separator plate 40, a second separator plate 30 disposed inside the first separator plate 20 and the third separator plate 40, and having a hydrogen flow path and an air flow path separately formed on both sides thereof; The water flow path plate 50 located between 20, 30, and 40, and the water flow path is processed on both sides to supply water from both sides, and the separation plates 20, 30, and 40 on both sides of the water flow path plate 50. Air exchanger 60 located between the ion exchange membrane 60 and the components 20, 30, 40, 50, and 60 in the stacked state as described above, and airtightly maintaining the air, hydrogen, and water passing through the respective flow paths. It consists of a fastening plate (10, 12) for pressing and fastening the components (20, 30, 40, 50, 60) on the inside have.

However, the structure of the fuel cell stack of the above-described configuration has the following problems.

In order to supply the moisture, the membrane humidifying part using the ion exchange membrane of the same type as a separate fuel cell stack in the stack, as described in the publication of 2002-0032874, can increase the output efficiency. The two structures occupy a large volume of the entire fuel cell stack, are constrained by installation space, and are expensive.

On the other hand, even in the publication of Publication No. 2003-0018078, which has a structure in which a fine passage is formed between the cooling water inlet hole and the hydrogen inlet hole to humidify using the cooling water, the humidification is performed using the fine passage, so that sufficient humidification of hydrogen is achieved. There is a problem that is not made and the heat recovery rate of the fuel cell is low.

The present invention has been made to solve the above-described problem, and not only does not require a separate external humidifier for the reactor humidification, but also requires a separate membrane humidifier in the stack, an external humidifier or a separate membrane humidifier in the stack occupies The purpose of the present invention is to provide a humidification unit integrated fuel cell separation plate capable of reducing space and weight, reducing ancillary cost and volume, and increasing heat recovery rate.

In the fuel cell separator of the present invention, a fuel cell separator and a fuel humidifier are provided with a fuel cell separator and a membrane humidifier with a humidifier unit integrated fuel cell separator. Humidification film for is formed.

In addition, it is preferable that a separation wall for separating the fuel cell part and the membrane humidifying part is further formed on the separation plate.

In addition, an oxidant flow path and a fuel gas flow path are formed on one side and the other surface of the separation plate so that the oxidant and the fuel gas flow, respectively, and a cooling water flow path is formed inside the separation plate.

According to this structure, since sufficient humidification can be performed through a membrane humidification part, heat recovery rate can be improved.

In addition, the space and weight occupied by an external humidifier or a separate membrane humidifier in the stack can be reduced, and the associated cost and volume can be reduced.

Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

For reference, among the configurations of the present invention to be described below, the same configuration as the prior art will be referred to the above-described prior art, and a detailed description thereof will be omitted.

Figure 4 is a schematic diagram showing a humidifying unit integrated fuel cell separator in accordance with a preferred embodiment of the present invention.

As shown in FIG. 4, in the fuel cell separator of the humidifying unit integrated fuel cell separator of the present embodiment, the fuel cell unit 110 and the membrane humidifier 130 are formed in the separator plate 100. The membrane-electrode assembly (MEA) is placed in the fuel cell unit 110, and the membrane humidifying unit 130 includes various types of humidification membranes 150 including an ion exchange membrane for humidifying the reactor. ) Is formed.

On the side of the membrane humidifier 130, a fuel gas inlet 450 through which fuel gas is supplied, a coolant outlet 550 through which coolant is discharged, and an oxidant outlet 300 through which oxidant is discharged are disposed. On the branch 110 side, a fuel gas outlet 400 through which fuel gas is discharged, a coolant inlet 500 through which coolant is supplied, and an oxidant inlet 350 through which oxidant gas is supplied are disposed.

On the other hand, the oxidizing gas passage 200 and the fuel gas passage (not shown) are formed on one side and the other side, respectively, so that the oxidant (oxygen or air) and fuel gas (hydrogen) can flow in the separating plate 100. It is preferable that a cooling water flow path (not shown) is formed in the.

Here, since it is shown in detail in the prior art, since only one surface of the separator 100 is shown in FIG. 4 of the present invention, only the oxidizing gas flow path 200 is shown.

The operation of this embodiment having the above-described configuration will be described below.

The dried oxidizer gas is supplied to the cathode of the fuel cell unit 110 in which the MEA is located through the oxidant inlet unit 350 so that a part of the oxidizer gas participates in the electrochemical reaction such as hydrogen ions and electrons moving from the anode. In this case, the unreacted oxidizing gas is supplied to the membrane humidifier 130 through the oxidizing gas flow path 200 while absorbing the reaction heat and water.

In this way, the unreacted oxidizing gas is supplied to the humidifying membrane 150 from the membrane humidifying unit 130 with heat and moisture, and then discharged through the oxidant outlet 350.

On the other hand, the fuel gas flow path is formed in a similar shape to the other surface of the oxidizing gas flow path 200, the dry fuel gas is supplied through the fuel gas inlet 450, the cathode while passing through the membrane humidifier 130 Heat and moisture are supplied by the humidifying membrane 150 of the membrane humidifying unit 130 which is supplied with moisture and heat from the hydrated oxidizing gas.

In this way, the fuel gas is supplied with heat and moisture and is supplied to the anode of the fuel cell unit 110 through the fuel gas flow path.

Part of the supplied fuel gas participates in the electrochemical reaction, and the remaining unreacted gas is discharged through the fuel gas outlet 400.

At this time, the coolant does not pass directly through the fuel cell unit 110, but is supplied through the coolant inlet 500 and discharged to the coolant outlet 550.

In this way, the fuel cell unit 110 and the membrane humidifier 130 are integrated into one separator plate 100 to supply heat and moisture generated from the cathode to the membrane humidifier 130 by unreacted oxidizing gas. The humidifying membrane 150 of the membrane humidifying unit 130 has a structure for supplying such heat and moisture to the anode fuel gas, thereby improving heat recovery and improving performance and efficiency of the fuel cell.

In addition, compared with the conventional fuel cell having an external humidifier, the membrane humidifying unit 600 is integrated in the MEA, thereby reducing the cost and volume of the fuel cell, thereby reducing the production cost.

Here, it is preferable that the separation plate 100 further includes a separation wall 170 for separating the fuel cell unit 110 and the membrane humidifying unit 130.

As such, the separation wall 170 is further formed on the separation plate 100 so that water flowing between the stacked separation plates 100 flows only toward the membrane humidifying unit 130 without flowing into the fuel cell unit 110. In this way, the humidification of the reactant may be achieved through the humidification membrane 150.

As described above, although described with reference to a preferred embodiment of the present invention, those skilled in the art will be able to vary the invention without departing from the spirit and scope of the invention described in the claims below. It may be modified or modified.

According to the humidification unit integrated fuel cell separator of the present invention as described above, there are the following effects.

The fuel cell unit and the membrane humidifying unit are formed together in one separator plate, and heat and moisture generated from the cathode are supplied to the membrane humidifying unit by an unreacted oxidizing gas, and the membrane for humidifying the membrane humidifying unit transfers the heat and moisture to the anode fuel gas. By having a supply structure, the heat recovery rate can be increased, and thus the performance and efficiency of the fuel cell can be improved.

In addition, compared with the conventional fuel cell having an external humidifier, since the membrane humidifying unit is integrated in the membrane-electrode-gasket assembly, the cost and volume of the fuel cell can be reduced, and the production cost is reduced.

Furthermore, the separation plate may further include a separation wall for separating the fuel cell unit and the membrane humidifying unit, such that water flowing between the stacked separation plates may flow only toward the membrane humidifying unit without flowing into the fuel cell unit.

Claims (3)

In the fuel cell separator, The separator of one sheet is formed with a fuel cell unit and a membrane humidifying unit, Humidification unit integrated fuel cell separator, characterized in that the membrane humidification unit is formed with a humidification membrane for humidifying the reactor. The method of claim 1, And a separator wall for separating the fuel cell unit and the membrane humidifier from the separator plate. The method according to claim 1 or 2, An oxidant flow path and a fuel gas flow path are formed on one side and the other surface of the separation plate so that an oxidant and a fuel gas flow, respectively, and a cooling water flow path is formed inside the separation plate.

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