KR102329252B1 - High-temperature polymer electrolyte memberance fuel cell stack for optimizing stack operation - Google Patents

Abstract

A high-temperature polymer electrolyte membrane fuel cell stack for optimizing stack operation according to an embodiment includes a plurality of first cooling plates; a plurality of second cooling plates located farther from the refrigerant inlet than the plurality of first cooling plates; a first cell assembly disposed between two adjacent first cooling plates and including a first number of first cell units; and a second cell assembly disposed between two adjacent second cooling plates and including a second number of second cell units smaller than the first number.

Description

High-temperature polymer electrolyte membrane fuel cell stack for optimization of stack operation

The following description relates to a high-temperature polyelectrolyte membrane fuel cell stack for optimizing the stack operation.

Fuel cells are attracting a lot of attention as a promising future clean energy technology because of their advantages such as high efficiency, eco-friendliness, and high power density. Among them, research on high-temperature polymer electrolyte membrane fuel cells (HT-PEMFC) is being actively conducted. The high-temperature polymer electrolyte membrane fuel cell uses a polybenzimidazole (PBI)-based electrolyte membrane doped with phosphoric acid and can be operated without separate humidification. No moisture trap is required. In addition, the performance degradation of the membrane electrode assembly (MEA) due to CO poisoning caused by CO poisoning in the high-temperature polymer electrolyte membrane fuel cell is significantly reduced at an operating temperature of 150 to 180° C. Due to this phenomenon, it is possible to minimize the CO removal process in the hydrogen reforming process. In addition, a high heat temperature close to 100℃ can be obtained, so the utilization of thermal energy is high.

However, the high-temperature polymer electrolyte membrane fuel cell still requires a lot of technological development. Theoretically, it has a high electrochemical reaction rate, but the performance of the developed high-temperature polyelectrolyte membrane fuel cell is somewhat inferior to that of the low-temperature polyelectrolyte membrane fuel cell. In addition, due to the harsh operating conditions of exposure to phosphoric acid and high temperature, durability is weak and the lifespan is short.

For example, when a part of the fuel cell is damaged under high-temperature operating conditions, the refrigerant permeates into the membrane electrode assembly (MEA), thereby deteriorating the performance of the fuel cell stack. In addition, since oil used as a refrigerant of a high-temperature polyelectrolyte membrane fuel cell stack has a higher viscosity than water, the oil causes a high differential pressure in the circulation path, which also causes damage to the fuel cell. In addition, since oil used as a refrigerant of the high-temperature polymer electrolyte membrane fuel cell stack operates at a high temperature, there is a problem in that the volume of the separator is changed while circulating the refrigerant passage formed inside the separator of the fuel cell, thereby promoting damage.

In addition, the high-temperature polymer electrolyte membrane fuel cell has a problem in that temperature non-uniformity occurs in the stacking direction under high-temperature operating conditions. This temperature non-uniformity has a problem of reducing the efficiency of the fuel cell.

An object of the present embodiment is to provide a high-temperature polyelectrolyte membrane fuel cell stack capable of solving a problem of causing deterioration in performance and durability due to temperature non-uniformity in the stack.

Another object of the present embodiment is to provide a high-temperature polymer electrolyte membrane fuel cell stack capable of solving a problem in which gas leakage occurs due to loose coupling of the stack.

A high-temperature polymer electrolyte membrane fuel cell stack for optimizing stack operation according to an embodiment includes a plurality of first cooling plates; a plurality of second cooling plates located farther from the refrigerant inlet than the plurality of first cooling plates; a first cell assembly disposed between two adjacent first cooling plates and including a first number of first cell units; and a second cell assembly disposed between two adjacent second cooling plates and including a second number of second cell units smaller than the first number.

The high-temperature polymer electrolyte membrane fuel cell stack for optimizing the stack operation includes: the plurality of first and second cooling plates; and an end plate for pressing the first and second cell assemblies; a plurality of third cooling plates positioned closer to the end plate than the plurality of second cooling plates; and a third cell assembly disposed between two adjacent third cooling plates and including a third number of third cell units greater than the second number.

The end plate may include: an upper end plate including the refrigerant inlet; and a lower end plate disposed opposite to the upper end plate, wherein the first cell assembly is located closer to the upper end plate than the second cell assembly, and the third cell assembly comprises: It may be located closer to the lower end plate.

The first cell assembly may include a plurality of first cell units each having a membrane electrode assembly; and a first dummy cell including a thermocouple therein and stacked in parallel with the plurality of cell units.

The first dummy cell may be disposed between two first cell units disposed in the middle among the plurality of first cell units.

The second cell assembly may include a plurality of second cell units each having a membrane electrode assembly; and a second dummy cell including a thermocouple therein and stacked in parallel with the plurality of cell units.

The first cell assembly may include a plurality of first cell units each having a membrane electrode assembly; and a heat insulating member surrounding the plurality of first cell units.

Further comprising a refrigerant hose for introducing a refrigerant into each of the plurality of first cooling plates and the plurality of second cooling plates, at least a portion of the heat insulating member, may be disposed between the plurality of first cell units and the refrigerant hose have.

A high-temperature polymer electrolyte membrane fuel cell stack for optimizing stack operation according to an embodiment includes a plurality of first cooling plates; a first cell assembly disposed between two adjacent first cooling plates and including a first number of first cell units; an end plate for pressing the plurality of first cooling plates and the first cell assembly; and a surface pressure measuring device disposed on one surface of the end plate to measure the force of the end plate pressing the plurality of first cooling plates and the first cell assembly.

The high-temperature polymer electrolyte membrane fuel cell stack for optimizing the stack operation includes: a clamping bar for fastening the end plate; and a relief spring disposed at the end of the clamping bar to apply pressure to the end plate, wherein the pressure gauge may be disposed between the relief spring and the end plate.

A plurality of the relief springs may be disposed along the edge of the end plate, and the surface pressure measuring device may be disposed under the plurality of relief springs, respectively.

According to an embodiment, by making the temperature in the stack uniform, it is possible to solve the problem of performance and durability degradation caused by temperature non-uniformity.

In addition, the internal temperature of the membrane electrode assembly (MEA) can be measured during actual operation by utilizing the dummy cells in the stack.

In addition, by preventing heat from being transferred to the refrigerant hose through the heat insulating material disposed between the stack and the refrigerant hose, it is possible to reduce the temperature non-uniformity phenomenon in the stack.

In addition, according to an embodiment, it is possible to prevent gas leakage by checking whether the stack is normally fastened through a plurality of surface pressure gauges disposed on the end plate.

1 is a front view of a high-temperature polymer electrolyte membrane fuel cell stack according to an embodiment.
2 is a front view of a high-temperature polymer electrolyte membrane fuel cell stack according to an embodiment.
3 is a partially exploded perspective view of a high-temperature polymer electrolyte membrane fuel cell stack according to an embodiment.
4 is a cross-sectional view of a high-temperature polymer electrolyte membrane fuel cell stack according to an embodiment.
5 is a plan view of a dummy cell according to an exemplary embodiment.
6 is a side view of a dummy cell according to an exemplary embodiment.
7 is a plan view of an end plate according to an embodiment.

Hereinafter, embodiments will be described in detail with reference to exemplary drawings. In adding reference numerals to the components of each drawing, it should be noted that the same components are given the same reference numerals as much as possible even though they are indicated on different drawings. In addition, in the description of the embodiment, if it is determined that a detailed description of a related known configuration or function interferes with the understanding of the embodiment, the detailed description thereof will be omitted.

In addition, in describing the components of the embodiment, terms such as first, second, A, B, (a), (b), etc. may be used. These terms are only for distinguishing the components from other components, and the essence, order, or order of the components are not limited by the terms. When it is described that a component is “connected”, “coupled” or “connected” to another component, the component may be directly connected or connected to the other component, but another component is between each component. It will be understood that may also be "connected", "coupled" or "connected".

Components included in one embodiment and components having a common function will be described using the same names in other embodiments. Unless otherwise stated, a description described in one embodiment may be applied to another embodiment, and a detailed description in the overlapping range will be omitted.

1 is a front view of a high-temperature polymer electrolyte membrane fuel cell stack according to an embodiment.

Referring to FIG. 1 , a high-temperature polyelectrolyte membrane fuel cell stack 10 (hereinafter, referred to as a “high-temperature PEMFC stack”) according to the embodiment includes a support assembly 11 , a first cell assembly 12a , and a second cell assembly. (12b), a plurality of cooling plates 13 and a current collector 14 for providing the generated current to the outside may be included. The plurality of cooling plates 13 includes a plurality of first cooling plates 13 disposed on an upper surface or a lower surface of each of the first cell assemblies 12a, and a plurality of first cooling plates 13 disposed on an upper surface or a lower surface of each of the second cell assemblies 12b. A plurality of second cooling plates 13 may be included. The first cooling plate and the second cooling plate do not have different configurations, and may be determined according to which one of the first cell assembly 12a and the second cell assembly 12b is disposed. For example, the cooling plate disposed on the lower surface of the first cell assembly 12a and the upper surface of the second cell assembly 12b may be referred to as a first cooling plate or a second cooling plate.

The support assembly 11 may support and press the first cell assembly 12a , the second cell assembly 12b , and the plurality of cooling plates 13 . The support assembly 11 may include an end plate 110 , a middle end plate 111 , a clamping bar 112 , a relief spring 113 , and a plurality of pressure gauges 119 .

The end plate 110 is a plate that is respectively fastened to both ends of the high-temperature PEMFC stack 10 , and may press other components disposed between the two end plates 110 . The end plate 110 may have, for example, a rectangular shape for optimal space utilization. A refrigerant inlet port (not shown) and a refrigerant outlet port (not shown) of the end plate 110 may be provided. For example, the refrigerant inlet port and the refrigerant outlet port may be provided by one or two, respectively.

The middle end plate 111 is a plate disposed in the center of the two end plates 110 , and can further improve the fixing force. The high-temperature PEMFC stack 10 has a higher degree of thermal expansion than the low-temperature PEMFC stack due to the characteristic of being operated at a high temperature. Accordingly, the risk of damage to the first cell assembly 12a and/or the second cell assembly 12b due to thermal expansion increases. In order to prevent the above problems, the thickness of the separator may be increased. On the other hand, since it is difficult to simply fix the two end plates 110 when the separation plate is thickened, by additionally inserting the middle end plate 111 in the center, the fixing force can be improved.

The clamping bar 112 is fastened between the two end plates 110 or between each end plate 110 and the middle end plate 111 , thereby forming components located between the two end plates 110 . can be fixed. The clamping bar 112 may be disposed to pass through at least a portion of the components positioned between the two end plates 110 to correctly align the components.

The relief spring 113 is provided at the end of the clamping bar 112 to apply pressure to the two end plates 110 or components located between each end plate 110 and the middle end plate 111 . can apply By adjusting the position and length of the relief spring 113, a constant pressure distribution may be applied to the first cell assembly 12a and/or the second cell assembly 12b.

The plurality of pressure gauges 119 may be disposed between the relief spring 113 and the end plate 110 . The plurality of surface pressure gauges 119 may measure the pressure applied to the internal components by the relief spring 113 . The user may determine whether the stack is normally fastened based on the pressure information measured by the plurality of surface pressure gauges 119 .

The first cell assembly 12a and the second cell assembly 12b may be disposed between the plurality of cooling plates 13, respectively, and a plurality of cell assemblies may be provided. For example, referring to FIG. 1 , nine first cell assemblies 12a are provided on the upper side of the middle end plate 111 , and nine second cell assemblies 12b are provided on the lower side of the middle end plate 111 . may be provided. The first cell assembly 12a may be disposed between two adjacent first cooling plates 13 .

The first cell assembly 12a may include a plurality of first cell units 121a, a first dummy cell 122a, and a first heat insulating member 123a.

Each of the plurality of first cell units 121a may include a membrane electrode assembly (MEA) provided therein, and two separators surrounding the membrane electrode assembly from upper and lower sides.

The first dummy cell 122a may measure the operating temperature of the membrane electrode assembly. For example, the first dummy cell 122a may include a plurality of built-in thermocouples. The first dummy cells 122a may be stacked in parallel with the plurality of first cell units 121a. The first dummy cell 122a may be formed of the same material as the separator constituting the plurality of first cell units 121a.

The first dummy cell 122a may be disposed between two first cell units 121a disposed in the middle among the plurality of first cell units 121a. For example, when there is an even number of a plurality of first cell units 121a, the first dummy cells 122a may be disposed between two first cell units 121a disposed in the middle. As another example, when an odd number of the plurality of first cell units 121a is present, the first dummy cell 122a is disposed between any two first cell units 121a among the three first cell units 121a disposed in the center. can be placed in According to this arrangement, the first dummy cell 122a can measure the real-time temperature of the membrane electrode assembly MEA while being less affected by the adjacent cooling plate 131 .

One first dummy cell 122a may be disposed in each of the plurality of first cell assemblies 12a. In this case, the temperature distribution in the stack may be measured based on the temperature information measured in each of the first dummy cells 122a.

The first heat insulating member 123a may surround the plurality of first cell units 121a and the first dummy cells 122a. The first heat insulating member 123a may reduce the amount of heat generated in the plurality of first cell units 121a transferred to the refrigerant hose 135 (refer to FIG. 4 ). Due to the first heat insulating member 123a, the temperature of the refrigerant transferred to the plurality of cooling plates 13 via the refrigerant hose 135 may be maintained relatively constant.

The second cell assembly 12b may include a plurality of second cell units 121b, a second dummy cell 122b, and a second heat insulating member 123b.

The number of the plurality of second cell units 121b of the second cell assembly 12b may be smaller than the number of the plurality of first cell units 121a of the first cell assembly 12a. For example, five first cell units 121a may be provided in one first cell assembly 12a, and four second cell units 121b may be provided in one second cell assembly 12b. have. An area of the first cell assembly 12a including four cell units is indicated by A, and an area of the second cell assembly 12b including five cell units is indicated by B. That is, the lower cooling plate ratio is higher than the upper cooling plate ratio. Here, the lower part means a part located relatively far from the refrigerant inlet through which the refrigerant is introduced from the outside, and the upper part means a part positioned relatively close to the refrigerant inlet port. Through such a structure, a temperature deviation within the stack can be reduced, and the efficiency of the fuel cell can be increased. In addition, it is possible to solve the problem of causing deterioration in performance and durability due to temperature non-uniformity.

The plurality of cooling plates 13 are for removing heat generated from the high-temperature PEMFC stack 10, and by flowing a refrigerant in an external manifold manner, the first cell assembly 12a and the second cell assembly 12b) The heat generated in it can be removed.

2 is a front view of a high-temperature polymer electrolyte membrane fuel cell stack according to an embodiment.

2, the high-temperature PEMFC stack 20 includes end plates 110 and 111, a first cell assembly 12c, a second cell assembly 12d, a third cell assembly 12e, a plurality of cooling plates, and A current collector 14 may be included. The plurality of cooling plates includes a plurality of first cooling plates disposed on an upper surface or a lower surface of each of the first cell assemblies 12c, and a plurality of second cooling plates disposed on an upper surface or a lower surface of each of the second cell assemblies 12d. and a plurality of third cooling plates disposed on an upper surface or a lower surface of each of the third cell assemblies 12e. The first cooling plate, the second cooling plate and the third cooling plate do not have different configurations, and are disposed in any one of the first cell assembly 12c, the second cell assembly 12d, and the third cell assembly 12e. It can be decided according to

The end plates 110 and 111 may include an upper end plate 110 including a refrigerant inlet, and a lower end plate 111 disposed opposite to the upper end plate 110 .

The first cell assembly 12c may be located closer to the upper end plate 110 than the second cell assembly 12d. The third cell assembly 12e may be located closer to the lower end plate 111 than the second cell assembly 12d. Since the first cell assembly 12c and the third cell assembly 12e are located close to the end plate, respectively, heat is absorbed by the end plate to maintain a relatively proper temperature. On the other hand, since the second cell assembly 12d is located far from the end plate, it is relatively difficult to maintain an appropriate temperature. Accordingly, the second cell assembly 12d may include a smaller number of cell units than the first cell assembly 12c and the third cell assembly 12e. For example, the first cell assembly 12c may include five cell units, the second cell assembly 12d may include four cell units, and the third cell assembly 12e may include five cell units.

Through such a structure, it is possible to reduce the temperature variation in the stack and increase the efficiency of the fuel cell. In addition, it is possible to solve the problem of causing deterioration in performance and durability due to temperature non-uniformity.

3 is a partially exploded perspective view of a high-temperature polyelectrolyte membrane fuel cell stack according to an embodiment, and FIG. 4 is a cross-sectional view of a high-temperature polyelectrolyte membrane fuel cell stack according to an embodiment.

3 and 4, a cell assembly disposed between two cooling plates 131 and 132 is shown. The cell assembly may include a plurality of cell units 121 , a dummy cell 122 , and a heat insulating member 123 .

The cooling plate 131 attached to the upper surface of the cell assembly includes inlet and discharge holes for hydrogen and oxygen, holes through which a plurality of clamping bars 112 (refer to FIG. 1 ) pass, and holes 131a and 131b through which refrigerant hoses pass. ) is provided. Similarly, the cooling plate 132 attached to the lower surface of the cell assembly includes an inlet and discharge hole for hydrogen and oxygen, a hole through which a plurality of clamping bars 112 (refer to FIG. 1 ) pass, and a hole 132a through which a refrigerant hose passes. , 132b) is provided.

Most of the heat emitted from the plurality of cell units 121 and the dummy cells 122 and transferred to the refrigerant hose 135 may be blocked by the heat insulating member 123 .

5 is a plan view of a dummy cell according to an exemplary embodiment, and FIG. 6 is a side view of the dummy cell according to an exemplary embodiment.

5 and 6 , the dummy cell 122 may include a dummy cell body 1221 , a dummy cell hole 1222 , and a plurality of thermocouples TC1 , TC2 , and TC3 .

The dummy cell body 1221 may have a shape corresponding to the cell unit 121 (refer to FIG. 1 ). For example, the dummy cell body 1221 may overlap the cell unit 121 based on the stacking direction of the stack. For example, when the cell unit 121 has a rectangular bottom surface, the dummy cell body 1221 may also have the same rectangular bottom surface.

The dummy cell hole 1222 may communicate with the hydrogen inlet and outlet and the oxygen inlet and outlet provided in the cell unit 121 (refer to FIG. 1 ), respectively.

The plurality of thermocouples TC1 , TC2 , and TC3 may be inserted into the dummy cell body 1221 in a direction perpendicular to the stacking direction of the stack. It should be noted that only one of the plurality of thermocouples TC1, TC2, and TC3 may be provided. The plurality of thermocouples TC1, TC2, and TC3 may be inserted at different depths to measure temperatures at different positions. For example, the first thermocouple TC1 may measure the temperature of the relatively edge portion, the third thermocouple TC3 may measure the temperature of the central portion, and the second thermocouple TC2 may measure the temperature of the first thermocouple TC1. and a temperature between the third thermocouple TC3 may be measured. In particular, in the case of the third thermocouple TC3, the temperature of the center of the unit in which the reaction of the membrane electrode assembly MEA occurs most actively may be measured.

7 is a plan view of an end plate according to an embodiment.

Referring to FIG. 7 , a plurality of relief springs 113 may be disposed along the edge of the end plate 110 , for example, ten. For example, when the end plate 110 has a rectangular shape, four relief springs 113 may be arranged along the long side and three along the short side. That is, ten relief springs 113 may be disposed.

A plurality of pressure gauges 119 may be disposed under each relief spring 113 . For example, when a plurality of relief springs 113 are disposed along the edge of the end plate 110 , the plurality of surface pressure gauges 119 may measure the pressure applied to the end plate 110 evenly. For example, when there are 10 relief springs 113 , 10 of the plurality of surface pressure gauges 119 may also be disposed. For example, when the pressure of the upper left side is measured to be relatively low, the user may implement a normal fastening by tightening the relief spring 113 on the upper left side more rigidly.

As described above, although the embodiments have been described with reference to the limited drawings, various modifications and variations are possible from the above description by those of ordinary skill in the art. For example, the described techniques are performed in an order different from the described method, and/or the described components of structures, devices, etc. are combined or combined in a different form than the described method, or other components or equivalents are used. Appropriate results can be achieved even if substituted or substituted by

Claims (4)

a plurality of first cooling plates;
a plurality of second cooling plates located farther from the refrigerant inlet than the plurality of first cooling plates;
one first cell unit disposed between two adjacent first cooling plates and disposed between a first number of first cell units and two first cell units disposed in the middle among the first number of first cell units a first cell assembly including one dummy cell;
a second cell assembly disposed between two adjacent second cooling plates, the second cell assembly including a second number of second cell units less than the first number; and
and a refrigerant hose passing through the plurality of first cooling plates and the plurality of second cooling plates and introducing the refrigerant into each of the plurality of first cooling plates and the plurality of second cooling plates,
A plurality of first cell units are provided between a first cooling plate of any one of the two adjacent first cooling plates and the first dummy cell, and a first one of the other of the two adjacent first cooling plates is provided. A plurality of first cell units are provided between the cooling plate and the first dummy cell,
The first dummy cell includes a dummy cell body and a plurality of thermocouples inserted into the dummy cell body in a direction perpendicular to a stacking direction of the plurality of first cooling plates,
The first cell assembly,
a plurality of first cell units each having a membrane electrode assembly; and
Surrounding the plurality of first cell units, a second direction perpendicular to the first direction without overlapping with the plurality of first cell units based on a first direction that is a stacking direction of the plurality of first cell units As a reference, overlapping the plurality of first cell units and disposed between the plurality of first cell units and the refrigerant hose, heat generated in the plurality of first cell units is directed toward the refrigerant hose in the second direction an insulating member that reduces the amount delivered;
The refrigerant hose is spaced apart from the plurality of first cell units in the second direction,
The heat insulating member is in close contact with the side surfaces of the plurality of first cell units, and is spaced apart from the refrigerant hose in the second direction based on the high temperature polymer electrolyte membrane fuel cell stack for optimizing stack operation.
The method of claim 1,
the plurality of first and second cooling plates, and an end plate for pressing the first and second cell assemblies;
a plurality of third cooling plates positioned closer to the end plate than the plurality of second cooling plates; and
High-temperature polyelectrolyte membrane fuel cell for optimizing stack operation, further comprising a third cell assembly disposed between two adjacent third cooling plates and including a third number of third cell units greater than the second number stack.
3. The method of claim 2,
The end plate is
an upper end plate including the refrigerant inlet; and
and a lower end plate disposed on the opposite side of the upper end plate,
The first cell assembly is located closer to the upper end plate than the second cell assembly,
wherein the third cell assembly is located closer to the lower end plate than the second cell assembly.
The method of claim 1,
The second cell assembly,
a plurality of second cell units each having a membrane electrode assembly; and
A high-temperature polymer electrolyte membrane fuel cell stack for optimizing stack operation, comprising a thermocouple therein, and a second dummy cell stacked in parallel with the plurality of cell units.

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