KR101698826B1 - Separator for fuel cell and fuel cell having the same - Google Patents

Abstract

According to an aspect of the present invention, there is provided a separator for a fuel cell and a fuel cell stack including the same, wherein the separator for a fuel cell is improved in structure to prevent distortion due to a temperature change. A separation plate body having one gas hole; And at least one rail part provided to reinforce a reaction area of the fuel cell in the separator main body.

Description

Technical Field [0001] The present invention relates to a separator for a fuel cell and a fuel cell stack including the separator.

The present invention relates to a separator for a fuel cell and a fuel cell stack including the separator, and more particularly, to a separator for a fuel cell and a fuel cell stack including the separator.

FIG. 1 is a perspective view showing a general planar solid oxide fuel cell, and FIG. 2 is a front view showing a general planar solid oxide fuel cell stack.

1 and 2, the solid oxide fuel cell 10 includes an electrolyte 14 having oxygen ion conductivity, and an air electrode 12 and a fuel electrode 14 as electrodes disposed on both sides thereof.

When oxygen and hydrogen used as a fuel are supplied to the fuel cell 10, the oxygen ions generated through the reduction reaction of oxygen in the air electrode 12 pass through the electrolyte 14 to the fuel electrode 16, and then reacts with the hydrogen supplied to the fuel electrode 16 to form water.

At this time, electrons generated in the fuel electrode 16 are transferred to the air electrode 12 and consumed, and electrons flow to the external circuit, and electric energy is generated using the electrons.

As described above, the fuel cell 10 composed of the electrolyte 14, the air electrode 12 and the fuel electrode 16 is referred to as a unit cell 10, and the amount of electric energy produced by one unit cell 10 is very limited In order to utilize the unit cells 10 for power generation, it is inevitable to form a 'stack' structure in which several unit cells 10 are stacked.

That is, when connecting the unit cells 10 constituting the fuel cell stack 50, the fuel cell separator plate 20 is installed to electrically connect the air electrode 12 and the fuel electrode 16, .

Therefore, the air electrode 12, the electrolyte 14, the fuel electrode 16, and the separator plate 20 for fuel cells, which are the basic units repeatedly installed to constitute the fuel cell stack 50, are referred to as constituent elements of the unit cell.

These components first form one unit cell 10, and after several unit cells 10 are repeatedly stacked, the fixing plates 32 and 34 and the stack bolts 36 for joining them are arranged at the uppermost and lowermost portions Thereby forming one fuel cell stack 50. The fuel cell stack 50 shown in FIG.

However, in the fuel cell stack 50 of a large-area solid stack, a temperature profile is generated by the heat of reaction generated in the plurality of unit cells 10, The temperature difference may be generated. In addition, the stress thus issued can cause thermal bucking of the separator plate 20 for the fuel cell, thereby increasing the change of the contact surface pressure and increasing the failure probability.

That is, the deformation of the separator plate 20 for the fuel cell affects the contact loss again, and with the change of the contact surface pressure, finally, it may lead to destruction of the unit cells 10 and the stacked fuel cell stacks 50 .

In addition, when the fuel cell stack 50 is operated, internal factors such as internal defects in the component material, manufacturing tolerances, internal stress, etc., and uneven pressure, temperature, gas Stress is generated due to external factors caused by composition, etc.

If such a stress is higher than a threshold value that the unit cell 10 can withstand, at least one of the components of the unit cell 10 may be destroyed or cause a contact loss, which may cause the fuel cell to operate abnormally.

Therefore, it is necessary to improve the structure so as to withstand the stresses in the production of the unit cell 10, and improvement of the structure for preventing the distortion due to the temperature gradient is required.

On the other hand, in order to prevent deformation of the separator plate 20 for fuel cells, a technique of forming a reinforcing portion in a partition wall forming a flow path has been disclosed in Korean Patent Application No. 10-2010-0134286. However, this method has been a factor to lower the reaction efficiency due to the reduction of the flow rate as a whole because the channel area of the separation plate 20 is reduced due to the reinforcing portion.

In addition, in the prior art, a rigid reinforcing structure is applied to prevent deformation that partially occurs in a portion having weak stiffness due to failure in being supported by a gasket or the like in a separator plate 20 for a fuel cell. 0071681. However, this type of structure reinforces the strength of a part of the region of the separator plate 20 for the fuel cell, so that it is impossible to reinforce the strength of the region where the reaction actually takes place. Particularly, There is a structural limitation in that it is not possible to prevent deformation such as distortion of the optical fibers 20.

It is an object of the present invention to provide a separator for a fuel cell and a fuel cell stack including the separator, the structure of which is improved so as to prevent a distortion due to a temperature change in a central portion of a region where a main reaction occurs in a fuel cell .

According to one aspect of the present invention, a separator plate for a fuel cell includes: a separator plate body having at least one gas hole; And at least one rail part extending from each of the ridges facing each other for preventing deformation at the center part, the reinforcing part being provided to reinforce the reaction area of the fuel cell reaction gas in the separator plate body, The rail portion includes a concave / convex portion convexly formed on one side of the separator main body, and the concave / convex portion is formed by stamping the separator main body.

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The rail portion may be formed on at least a part of a virtual line connecting vertexes opposite to each other with respect to the center of the separator plate body.

The rail portion may be formed on at least a part of an imaginary line connecting surfaces of the separator main body facing each other with respect to the center.

A fuel cell stack according to an aspect of the present invention includes: a unit cell including the above-described separator plate for a fuel cell; And a coupling unit coupling at least one unit cell stacked in a stack form.

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Here, the rail portion may be formed on at least a part of a virtual line connecting vertexes opposite to each other with respect to the center of the separator plate body.

The rail portion may be formed on at least a part of an imaginary line connecting surfaces of the separator main body facing each other with respect to the center.

The flow path plate may further include a flow path plate provided in a region other than the rail portion protruding from the reaction region of the separator for fuel cells, the flow path plate having a gas channel for guiding the circulation of the reaction gas for fuel cells.

According to an embodiment of the present invention, strength can be reinforced by the rails provided inside the separator plate for a fuel cell, warping due to temperature changes can be prevented, contact failure, breakage and the like can be prevented, Durability and reliability can be improved

In addition, the present embodiment can prevent abnormal operation of the fuel cell stack, improve the overall performance, and reduce the overall height of the separator plate for a fuel cell and the fuel cell stack to which the separator plate is applied.

1 is a perspective view showing a general planar solid oxide fuel cell.
2 is a front view of a typical planar solid oxide fuel cell stack.
3A and 3B are perspective views illustrating a separator plate for a fuel cell according to an embodiment of the present invention.
4A and 4B are plan views of a separator plate for a fuel cell according to an embodiment of the present invention.
5 is a sectional view taken along the line I-I in Fig.
6A and 6B are exploded perspective views illustrating a separator plate for a fuel cell according to another embodiment of the present invention.
7 is a sectional view of a separator plate for a fuel cell according to another embodiment of the present invention.
8 is a plan view of a separator plate for a fuel cell according to another embodiment of the present invention.

Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings. The embodiments of the present invention can be modified into various other forms, and the scope of the present invention is not limited to the embodiments described below. The shape and the size of the elements in the drawings may be exaggerated for clarity and the same elements are denoted by the same reference numerals in the drawings.

In this embodiment, the fuel cell is a power generation system that converts the chemical energy of the fuel into electrical energy. For example, fuel (for example, hydrogen gas) is supplied to the fuel electrode on the anode side, For example, air), and converts them into electric energy using the chemical energy generated during the reaction. Such a reaction process is represented by the following formula (1) or (2).

On the other hand, fuel cells can be classified into low-temperature type and high-temperature type according to operating temperature and electrolyte type, and PEMFC (Proton Exchange Membrane Fuel Cell) Cell), SOFC (Solid Oxide Fuel Cell), and SOEC (solid oxide electrolysis cell) using SOFC reverse reaction are typically used.

Fuel cells can continuously generate electricity in the process of continuously injecting fuel (hydrogen) and oxidizer. In case of fuel, it is necessary to increase the utilization rate in consideration of power generation efficiency and economical efficiency so that commercial value can be increased.

For example, the solid oxide fuel cell 10 of the present embodiment may include an electrolyte 14 having oxygen ion conductivity and an air electrode 12 and a fuel electrode 16 as electrodes disposed on both sides thereof. The fuel cell comprising the electrolyte 14, the air electrode 12 and the fuel electrode 16 is referred to as a unit cell 10, and the unit cell 10 is provided between the air electrode 12 and the fuel electrode 16, The oxidant or the fuel as the reaction gas can be circulated and reacted to generate energy.

In this embodiment, a plurality of unit cells 10 may be stacked and stacked in a stack to form a fuel cell stack in order to increase the production of electric energy.

At this time, in order to prevent mixing of the reaction gas by electrically connecting the air electrode 12 and the fuel electrode 16 in each unit cell 10 of the fuel cell stack 50, the improved fuel cell separator plate 110 ) Can be installed.

FIGS. 3A and 3B are perspective views illustrating a separation plate for a fuel cell according to an embodiment of the present invention, and FIGS. 4A and 4B are plan views of a separation plate for a fuel cell according to an embodiment of the present invention. 5 is a cross-sectional view taken along the line I-I in Fig.

The number of the unit cells 10 stacked in the fuel cell stack 50 may vary depending on the area of the unit cells 10, the structure of the unit cells, and the like. For example, 5 to 20 unit cells 10 may be stacked have.

Meanwhile, in this embodiment, the separator plate 110 for a fuel cell is provided as a flat plate and may include a separator plate body 112 made of a metal having electrical conductivity.

Also, the separator plate body 112 may be provided with at least one gas hole 114, 116. These gas holes 114 and 116 can pass through a fuel or an oxidant used as a reaction gas for a fuel cell.

At this time, the separator plate 110 for a fuel cell may be provided in various forms according to a position and a direction in which the fuel and the oxidizer are supplied. For example, the separator 110 for a fuel cell includes a co-flow system in which gas holes 114 and 116 for supplying and discharging a fuel and a reactant gas as an oxidant are arranged in the same direction, A count-flow system in which gas holes 114 and 116 to which a reaction gas is supplied and discharged are disposed in opposite directions to each other and gas holes 114 and 116 through which a reaction gas as a fuel and an oxidant are supplied and discharged, And a cross-flow system disposed at right angles to each other. In addition, the fuel cell and the oxidizer can be provided in various forms circulating the fuel and the oxidant. 10) can be determined.

In the present embodiment, the reaction heat may be generated in the fuel cell stack 50 as the fuel and the reactive gas, which is the oxidizer, react with each other in the unit cell 10, A temperature profile may be generated.

In addition, stress may be generated due to the temperature deviation of the unit cells 10 during operation of the fuel cell stack 50, and such a stress change causes deformation such as thermal buckling in the separator plate 110 for the fuel cell .

In particular, in the fuel cell separator 110, deformation stress may concentrate at the central portion of the reaction zone where the main reaction of the reaction gases occurs, and thus, deformation such as thermal distortion may occur.

Deformation such as thermal distortion of the fuel cell separator 110 can be made thicker or minimized by using a material having a higher strength.

However, if the thickness of the separator 110 for the fuel cell is increased, the overall height of the fuel cell stack 50 is increased and the cost is increased. Therefore, if possible, the thickness of the separator 110 for a fuel cell may be reduced . A method of minimizing the temperature gradient in the fuel cell stack 50 is also possible in order to minimize deformation such as thermal distortion of the separator plate 110 for a fuel cell.

However, there is a limit in minimizing the temperature gradient in the fuel cell stack 50, and as the temperature gradient is increased as the stack 50 of fuel cells is provided in a large-area high-stack structure, There is a limitation in minimizing the temperature gradient only by thickening the material or using a material having a higher strength.

The improved separator plate 110 for a fuel cell in the present embodiment is provided with at least one separator plate 112 for increasing the strength in order to prevent deformation such as thermal distortion occurring in the separator plate for a fuel cell during operation of the fuel cell stack The rail 120 may be formed.

The rail 120 may be formed on at least one surface of the separator main body 112. In addition, the rail 120 may include a concavo-convex portion convexly formed on the separator main body 112 in one direction.

In this embodiment, the concavo-convex portion can be formed by stamping the separator main body 112.

In general, the separating plate main body 112 is provided in the form of a rectangular flat plate. In this embodiment, the rail part 120 is a virtual line connecting the faces opposed to each other with respect to the center of the separating plate body 112, ) May be formed at least in part of the char.

3A and 4A, the rail 120 may be formed in the transverse and longitudinal directions of the separator plate body 112 except for the central region, and may be formed only in a part of the imaginary line region It may be formed intermittently in the form of a dotted line.

As shown in FIGS. 3B and 4B, the rail 120 'has a central portion of about ten (10) charities, which is a virtual line connecting surfaces facing each other with respect to the center of the separator plate body 112 And may be formed so as to be continuously connected to each other.

The separator plate 110 for the fuel cell further includes a gas channel 118 which forms a flow path for guiding the circulation of the reaction gas supplied and discharged through the gas holes 114 and 116 in the reaction region of the separator plate body 112 May be formed.

Preferably, such a gas channel 118 can circulate through the interrupted portion of the rail 120. Such a gas channel 120 may be formed in various forms such that the reaction gas, which is a fuel or an oxidant, can flow uniformly even with the exception of the embodiments disclosed in the specification of the present invention.

Also, in this embodiment, the projected height of the rail 120 may be equal to or less than the height of the gas channel 118, and may be less than about 2 mm, for example.

When the separator plate 120 for a fuel cell configured as described above is used, the deformation displacement against the twist can be greatly reduced as compared with the conventional separator plate for a fuel cell.

For example, in the case of a separator for a fuel cell having a length and a length of 25 cm and a thickness of 1 mm, a distortion of about 3 mm is generated due to a temperature variation occurring in the unit cell of the fuel cell stack. In the case of the separator plate 110 for a fuel cell in which the length and the length are 25 cm and the thickness is 1 mm and the reamer 120 is formed as in the embodiment, It can be seen that a warping change of about 1 mm occurs due to a temperature variation or the like.

The fuel cell stack 50 including the unit cells 10 to which the separator 110 for a fuel cell according to the present embodiment is applied is not limited to thermal buckling of the separator plate 110 due to temperature variations, Deformation can be suppressed, and consequently, the change in the contact surface pressure of the unit cell 10 and the probability of failure can be reduced.

In addition, when the fuel cell stack 50 is operated, internal factors such as internal defects in component materials, manufacturing tolerances, internal stresses, and the like are caused by the uneven pressure, temperature, gas composition, Stress may occur due to external factors.

If the stress generated during the operation of the fuel cell stack 50 is higher than the threshold value that can be tolerated by the unit cell 10, the unit cell 10 may be destroyed or contact loss may be caused, The unit cell 10 to which the separator plate 120 for fuel cells according to the present embodiment is applied can be suppressed from being warped and the stress resistance can be enhanced and the fuel due to the contact loss and gas leakage It is possible to reduce operational errors of the battery, thereby increasing the durability and reliability of the fuel cell stack 50.

The separator plate 110 for a fuel cell according to the present embodiment can suppress distortion and reinforce stress due to the structure of the rail 120, thereby improving the design flexibility of the separator plate 110 for fuel cells, It is also possible to provide convenience of manufacturing together.

Although the gas channel 118 is formed integrally with the separator plate 112 in the present embodiment, the shape and position of the gas channel 118 are not limited, It may be provided separately from the separator plate body 112 as shown in Fig.

6A and 6B are exploded perspective views illustrating a separator plate for a fuel cell according to another embodiment of the present invention, and FIG. 7 is a cross-sectional view of a separator plate for a fuel cell according to another embodiment of the present invention.

For example, the separator plate 210 for a fuel cell includes a separator plate body 212, and the separator plate body 212 may be provided with gas holes 214 and 216 through which a fuel or a reactive gas, have.

 The fuel cell separator plate 210 may further include a flow field plate 230 or 230 'provided in an area other than the rails 220 and 220' protruding into the reaction area of the separator plate body 212.

The flow plates 230 and 230 'may be formed with gas channels 232 and 232', which are used as channels for guiding the circulation of the fuel or the oxidant, which is a reaction gas for the fuel cell.

As described above, the gas channels 232 and 232 'can be formed in the flow path plates 230 and 230' coupled to the separation plate main body 212, and the fuel gas or the oxidant, which is a reaction gas for the fuel cell, Can be modified into various forms.

The shape of the rail portions 120 and 220 is not limited, and the rail portions 120 and 220 may be integrally formed with the rail portions 120 and 220, 220 may be formed in various shapes to prevent thermal deformation of the separator plates 212, 222.

8 is a plan view of a separator plate for a fuel cell according to another embodiment of the present invention.

8, the fuel cell separator plate 310 includes a separator plate body 312. The separator plate body 312 is provided with gas holes 314, 316 May be formed.

The rail portions 320 and 320 'may be formed on at least a part of the diagonal direction, that is, the' X 'line, which is a virtual line connecting vertexes opposite to each other with respect to the center of the separator plate body 312.

That is, as shown in FIG. 8A, the rail 320 may be formed in the separating plate body 312 except for the central region, or may be formed only in a part of the virtual line region, that is, It is possible.

8B, the rails 320 'may be formed continuously in the diagonal direction on the separator plate body 312, so that the center portions arranged in the respective diagonal directions may be continuously formed Do.

It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims and their equivalents. It will be clear to those who have knowledge.

10: Unit cell 50: Fuel cell stack
110: separator plate for fuel cell 112: separator plate body
114, 116: gas hole 118: gas channel
120: Le Mans

Claims (9)

A separation plate body having at least one gas hole; And
And at least one rail extending from each of the ridges facing each other for preventing deformation at the central portion, the ridges being provided to reinforce the reaction gas reactive region of the fuel cell in the separator plate main body,
Wherein the rail portion includes a concavo-convex portion convexly formed on one side of the separator plate body,
Wherein the concavoconvex portion is formed by stamping the separator plate main body. delete delete [2] The apparatus of claim 1,
And at least a part of imaginary lines connecting vertexes opposite to each other with respect to the center in the separator plate main body. [2] The apparatus of claim 1,
Wherein at least a part of the imaginary line connecting the surfaces facing each other with respect to the center is formed on the separator plate body. A unit cell comprising a separator for a fuel cell according to claim 1; And
A coupling unit for coupling at least one unit cell stacked in a stack form;
And a fuel cell stack. 7. The apparatus of claim 6,
Wherein at least a part of a virtual line connecting vertexes opposite to each other with respect to a center of the separator plate body is formed. 7. The apparatus of claim 6,
Wherein at least a part of the imaginary line connecting the surfaces facing each other with respect to the center in the separator plate main body is formed. The method of claim 6,
Further comprising a flow path plate provided in a region other than a rail portion protruding from a reaction region of the separator for fuel cells and having a gas channel for guiding the circulation of the reaction gas for fuel cells.

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