KR20230069721A - Electrochemical hydrogen compressor - Google Patents

Abstract

An electrochemical hydrogen compressor according to an aspect of the present invention includes a membrane-electrode assembly including a cathode and an anode, an anode-side separator disposed on the anode side and supplying hydrogen to the anode, and disposed on the cathode side, a pair of end plates respectively disposed on both ends of the cathode-side separator, the anode-side separator, and the cathode-side separator, the membrane-electrode assembly, the anode-side separator, and the cathode-side separator for discharging hydrogen from the cathode; It includes a gasket positioned between the separator plates to prevent hydrogen from leaking, and the gasket may have a ring shape including an inner circumferential surface having irregularities.

Description

Electrochemical hydrogen compressor {ELECTROCHEMICAL HYDROGEN COMPRESSOR}

The present invention relates to an electrochemical hydrogen compressor.

A hydrogen car generates its own electricity through a chemical reaction between hydrogen and oxygen and is configured to drive by driving a motor. Therefore, a hydrogen car has a hydrogen tank (H2　Tank) in which hydrogen (H2) is stored, a stack (FC STACK: Fuel Cell Stack) that generates electricity through the oxidation-reduction reaction of hydrogen and oxygen (O2), and a system for draining the generated water. It has a structure including a battery for storing electricity generated in the stack, a controller for converting and controlling the generated electricity, a motor for generating driving force, and the like, as well as various devices for the stack.

Among them, a stack refers to a fuel cell body in which tens or hundreds of cells are stacked in series, and has a structure in which a plurality of cells are stacked between end plates, and the inside of each cell is partitioned with an electrolyte membrane, and one side is The other side of the anode is provided with a cathode. A separator is disposed between each cell to limit the flow path of hydrogen and oxygen, and the separator is made of a conductor to move electrons during a redox reaction.

A hydrogen charger is needed to supply hydrogen to a hydrogen car. The hydrogen charger includes a hydrogen tank for storing hydrogen and a supply device for supplying hydrogen to a hydrogen vehicle. In addition, the hydrogen charger may include a hydrogen compressor for compressing hydrogen.

As such a hydrogen compressor for a hydrogen charger, various conventional mechanical fluid compressors can be used. The mechanical hydrogen compressor includes a member that moves by receiving a driving force. Therefore, when the mechanical hydrogen compressor is operated, there is a problem of vibration of the moving member and noise caused by it. In addition, such mechanical hydrogen compressors are expensive, and there are problems such as wear and tear on moving parts. Accordingly, an electrochemical hydrogen compressor having less noise and vibration than a mechanical hydrogen compressor and being advantageous in terms of maintenance can be utilized.

However, electrochemical hydrogen compressors are operated at higher pressures than mechanical hydrogen compressors. If the same circular gaskets as fuel cells are used, the gaskets are deformed, sealing is not performed smoothly and hydrogen gas leaks. There is a problem with

Republic of Korea Patent No. 10-1916892 Republic of Korea Patent No. 10-1918354

In order to solve the above problem, an object of the present invention is to provide an electrochemical hydrogen compressor capable of reducing external deformation by dispersing stress generated inside a gasket.

An electrochemical hydrogen compressor according to an aspect of the present invention includes a membrane-electrode assembly including a cathode and an anode, an anode-side separator disposed on the anode side and supplying hydrogen to the anode, and disposed on the cathode side, a pair of end plates respectively disposed on both ends of the cathode-side separator, the anode-side separator, and the cathode-side separator, the membrane-electrode assembly, the anode-side separator, and the cathode-side separator for discharging hydrogen from the cathode; It includes a gasket positioned between the separator plates to prevent hydrogen from leaking, and the gasket may have a ring shape including an inner circumferential surface having irregularities.

The inner circumferential surface includes a protrusion protruding toward the center of the gasket and a groove connected to the protrusion and recessed in an opposite direction to the protrusion, and the protrusion and the groove may be repeatedly disposed at equal intervals.

The protruding portion and the groove portion may have a semicircular shape.

A radius of the protruding portion and the groove portion may be 0.3 mm to 0.5 mm.

The protrusion and the groove may have the same radius.

In the gasket, the first thickness, which is the maximum thickness of the gasket, may be 10 to 20 times the radius.

In the gasket, a difference between the second thickness, which is the minimum thickness of the gasket, and the first thickness may be within 2 to 3 times the radius.

The gasket may be made of a non-metal elastic material.

As described above, the electrochemical hydrogen compressor according to one aspect of the present invention can reduce external deformation by dispersing stress generated inside the gasket, thereby increasing the sealing effect of the electrochemical hydrogen compressor gasket.

1 is a perspective view of an electrochemical hydrogen compressor according to an embodiment of the present invention.
2 is an exploded perspective view of the electrochemical hydrogen compressor of FIG. 1;
Fig. 3 is a plan view of the gasket of Fig. 1;
FIG. 4 is an enlarged view of part A of FIG. 3 .
FIG. 5 is a diagram showing stress in the circumferential direction acting on FIG. 4 .
FIG. 6 is an enlarged view of part B of FIG. 3 .
FIG. 7 is a diagram showing outer strain according to the material of the gasket of FIG. 3 .
FIG. 8 is a diagram showing outer strain according to the shape of the gasket of FIG. 3 .

Since the present invention can apply various transformations and have various embodiments, specific embodiments will be exemplified and described in detail in the detailed description. However, it should be understood that this is not intended to limit the present invention to specific embodiments, and includes all transformations, equivalents, and substitutes included in the spirit and scope of the present invention.

Terms used in the present invention are only used to describe specific embodiments, and are not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly dictates otherwise. In the present invention, terms such as 'include' or 'having' are intended to designate that there is a feature, number, step, operation, component, part, or combination thereof described in the specification, but one or more other features It should be understood that the presence or addition of numbers, steps, operations, components, parts, or combinations thereof is not precluded.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. At this time, it should be noted that in the accompanying drawings, the same components are indicated by the same reference numerals as much as possible. In addition, detailed descriptions of well-known functions and configurations that may obscure the gist of the present invention will be omitted. For the same reason, in the accompanying drawings, some components are exaggerated, omitted, or schematically illustrated.

Hereinafter, an electrochemical hydrogen compressor 10 according to an embodiment of the present invention will be described.

1 is a perspective view of an electrochemical hydrogen compressor according to an embodiment of the present invention, and FIG. 2 is an exploded perspective view of the electrochemical hydrogen compressor of FIG. 1 .

1 and 2, the electrochemical hydrogen compressor 10 according to an embodiment of the present invention includes an end plate 100, a membrane electrode assembly (MEA) 200, and a gas diffusion layer (GDL: A gas diffusion layer 300 ), a separation plate 400 , a current collector plate 500 , a gasket 600 and a coupling member 700 may be included.

Hydrogen (H ₂ ) may be provided to an anode, which is an oxidation electrode of a membrane-electrode assembly 200 described below of the electrochemical hydrogen compressor 10 . Hydrogen provided to the anode can be separated into hydrogen ions and electrons by causing an oxidation reaction due to a potential difference. The separated hydrogen ions may move to a cathode, which is a reduction electrode, through a polymer electrolyte membrane (PEM). The separated electrons can also move to the cathode through an external circuit. Hydrogen molecules may be generated by a reduction reaction of hydrogen ions at the cathode. Accordingly, hydrogen supplied to the anode moves to the cathode due to a potential difference between the anode and the cathode, and accordingly, the pressure of the hydrogen inside the cathode increases and the hydrogen can be compressed.

Compared to mechanical hydrogen compressors, the electrochemical hydrogen compressor 10 based on the above operating method can obtain high purity hydrogen free from contamination by lubricating oil (oil) for mechanical operation, and consumes less energy when compressed at high pressure. has an advantage. In addition, since there is no separate driving member, vibration and noise can be reduced and maintenance can be easy.

Compression with only one cell including the membrane-electrode assembly 200, the gas diffusion layer 300, the separator 400, the current collector 500 and the gasket 600 of the electrochemical hydrogen compressor 10 Since it cannot handle the required flow rate of hydrogen, a plurality of cells may be stacked. A plurality of cells may be sequentially stacked, and end plates 100 described below may be positioned at both ends of the plurality of cells and coupled by a coupling member 700 to provide fastening pressure to the plurality of cells to be fixed.

Here, those with ordinary knowledge in the technical field related to this embodiment know that other general-purpose components may be further included in the electrochemical hydrogen compressor 10 in addition to the components shown in FIGS. 1 and 2 I can understand.

The end plate 100 is a pair of plates respectively disposed at both ends of an anode-side separator and a cathode-side separator, which will be described later, and can provide clamping pressure to an internal cell. The end plates 100 may be positioned at both ends of the electrochemical hydrogen compressor 10 and coupled by a coupling member 700 to be described later to provide clamping pressure. That is, the plurality of membrane-electrode assemblies 200, the gas diffusion layer 300, the separator 400, the current collector plate 500, and the gasket 600 are stacked between the end plates 100, and the end plates positioned at both ends ( 100) may be fixed by the coupling member 700. Accordingly, it is possible to fix the cells by providing a constant fastening pressure to the cells in which the end plates 100 are stacked.

The end plate 100 is a flat plate having a cross-sectional area sufficient to cover a cell including the membrane-electrode assembly 200, the gas diffusion layer 300, the separator 400, the current collector plate 500, and the gasket 600. can be in the form

A plurality of through holes for coupling by the coupling member 700 may be formed on the outer side of the end plate 100 . If the size and distribution of the surface pressure acting on the plurality of stacked cells is not uniform, there may be a problem in that the efficiency of hydrogen compression decreases due to the leakage of the reactive gas and the increase in the contact resistance. Thus, the through holes formed in the end plate 100 may be formed symmetrically with respect to the center of the end plate 100 so that the end plate 100 can evenly press the cells stacked therein.

Since the end plate 100 should not be deformed despite the tightening force of the coupling member 700, it may be made of a material having sufficient rigidity, such as steel or reinforced plastic. However, the shape and material of the end plate 100 are not limited thereto and may have various shapes and materials.

The membrane-electrode assembly 200 includes a cathode (not shown) and an anode (not shown), and may cause a chemical reaction of hydrogen supplied to the anode. The membrane-electrode assembly 200 may be a film-type assembly.

The membrane-electrode assembly may have a structure in which an anode, also called an anode, and a cathode, also called a reduction electrode, are attached with a polymer electrolyte membrane interposed therebetween. The membrane-electrode assembly 200 may include a cathode-side catalyst layer (not shown) disposed on a surface corresponding to a cathode and an anode-side catalyst layer (not shown) disposed on a surface corresponding to an anode described below.

Hydrogen supplied to the anode of the membrane-electrode assembly 200 may be separated into hydrogen ions and electrons through an oxidation reaction. The separated hydrogen ions may move to the cathode and generate hydrogen molecules by a reduction reaction. Accordingly, the pressure of hydrogen existing in the cathode is increased so that the hydrogen can be compressed. However, the configuration of the membrane-electrode assembly 200 is not limited thereto and may be changed within a range that can be employed by those skilled in the art related to the present invention.

The gas diffusion layer 300 may be disposed outside the anode and cathode and may be a passage through which hydrogen, a reactant, is transferred from the passage to the electrode. The gas diffusion layer 300 may have a structure having microporous layers on porous carbon paper and cloth. The gas diffusion layer 300 may provide a passage through which hydrogen moves to the catalyst layer and serve as a current conductor between the catalyst layer and the separator 400 to be described later.

Since the gas diffusion layer 300 diffuses hydrogen into the catalyst layer and serves as a current conductor, the performance and durability of the electrochemical hydrogen compressor 10 may be affected. Accordingly, the gas diffusion layer 300 may be made of carbon paper or carbon fiber, which is a material having high gas permeability, electrical conductivity, hydrophobicity, and thermal stability. However, the structure and material of the gas diffusion layer 300 are not limited thereto and may be changed within a range that can be employed by those skilled in the art related to the present invention.

The separator 400 may include an anode-side separator 410 and a cathode-side separator 420 . The separator 400 may include a flow path (not shown) and structurally support the gas diffusion layer 300 and the membrane-electrode assembly 200 . In addition, the separator 400 may simultaneously serve as a conductor connecting the anode and cathode of the membrane-electrode assembly 200 in series.

The separator 400 can evenly distribute and supply hydrogen required for the reaction of the electrochemical hydrogen compressor 10 to the entire surface of the membrane-electrode assembly 200 . In addition, the current generated by the oxidation reaction of hydrogen at the anode can be collected and delivered.

The separator 400 may have a thin flat plate shape. The separator 400 has excellent electrical and thermal conductivity, corrosion resistance, low gas permeability, etc., and may be made of stainless, titanium, or aluminum having sufficient rigidity to serve as a structural support. there is. However, the shape and material of the separator 400 are not limited thereto, and various shapes and materials may be used.

The anode-side separator 410 is disposed on the anode side to supply hydrogen to the anode. The cathode-side separator 420 is disposed on the cathode side, and may discharge hydrogen from the cathode. Positions of the anode-side separator 410 and the cathode-side separator 420 may be changed according to the structure of a cell stacked therein.

The current collector plate 500 may be positioned between the separator plate 400 and the end plate 100 to collect electricity. The current collecting plate 500 may have a plate shape including terminals for collecting electricity. The current collector 500 may be an anode-side current collector or a cathode-side current collector depending on the structure of a cell stacked therein. However, the structure and shape of the current collector 500 are not limited thereto and may be changed within a range that can be employed by those skilled in the art related to the embodiments of the present invention.

Hereinafter, a gasket 600 according to an embodiment of the present invention will be described.

3 is a plan view of the gasket of FIG. 1, FIG. 4 is an enlarged view of portion A of FIG. 3, FIG. 5 is a view showing stress in the circumferential direction acting on portion B of FIG. 4, and FIG. 6 is a view showing portion B of FIG. This is an enlarged drawing.

Referring to FIGS. 3 to 6 , the gasket 600 may include an outer circumferential surface 610 and an inner circumferential surface 620 . The gasket 600 is positioned between the membrane-electrode assembly 200 and the anode-side separator 410 and the cathode-side separator 420 to prevent leakage of hydrogen. The gasket 600 may have a ring shape surrounding the inner space 630 and including an inner circumferential surface 620 having irregularities. Since the gasket 600 has an uneven inner circumferential surface, stress applied from the inside can be dispersed. As the stress applied from the inside of the gasket 600 is dispersed, the outer deformation of the gasket 600 is reduced, thereby improving the sealing effect.

The gasket 600 may be made of a non-metal elastic material such as polytetrafluoroethylene (PTFE). When the gasket 600 is made of a metal material, the strain is small, but if a problem occurs in alignment due to the stacking of a plurality of cells, a tolerance may occur and hydrogen may leak.

In the gasket 600, the first thickness t1, which is the maximum thickness of the gasket 600, may be 10 to 20 times the radius r1 of the protrusion and the radius r2 of the groove. When the first thickness t1 is less than 10 times the radius of the protrusion r1 and the radius of the groove r2, the outer circumferential surface 610 of the gasket is not spaced a certain distance from the inner circumferential surface 620 where large deformation occurs due to internal pressure. The outer strain of the gasket 600 may increase. As the outer strain of the gasket 600 increases, the sealing effect of the gasket 600 may decrease.

When the first thickness t1 of the gasket 600 exceeds 20 times the radius of the protrusion r1 and the radius of the groove r2, the sealing effect of the gasket 600 is not greatly improved. The outside of the gasket 600 protrudes to increase the volume of the entire electrochemical hydrogen compressor 10 . In addition, the gasket 600 protruding to the outside may receive an impact from the outside, and thus the gasket 600 may be damaged.

In the gasket 600, a difference between the second thickness t2 and the first thickness t1, which is the minimum thickness of the gasket 600, may be within 2 to 3 times of the protrusion radius r1 and the groove radius r2. (See Figures 4 and 6). This is because, as will be described later, when the difference between the first thickness t1 and the second thickness t2 is large, stress in the circumferential direction is not offset and the stress dispersion effect is reduced.

Referring to FIG. 5 , stresses in the circumferential direction of the protruding portion 621 and the groove portion 622 described later are indicated by upward and downward arrows on the left and right sides of the boundary between the inner space 630 and the inner circumferential surface 620, respectively. Stresses in the circumferential direction of the protrusion 621 and the groove 622 act in opposite directions, so they can be canceled out.

In this case, as the difference between the stress in the circumferential direction of the protrusion 621 and the stress in the circumferential direction of the groove 622 is smaller, the stress is offset, so that deformation of the gasket 600 can be prevented. The stress in the circumferential direction is proportional to the product of the internal pressure and the radius of curvature, and is inversely proportional to the thickness of the gasket 600 . Since the internal pressure and curvature radius of the protrusion 621 and the groove 622 are the same, when the difference between the first thickness t1 and the second thickness t2 is small, the stress of the protrusion 621 and the groove 622 in the circumferential direction size difference can be small. Therefore, it may be preferable that the difference between the first thickness t1 and the second thickness t2 is within three times the radius r1 of the protrusion and the radius r2 of the groove. However, the difference between the first thickness t1 and the second thickness t2 is at least twice the radius of the protrusion r1 and the radius of the groove r2, so the difference between the first thickness t1 and the second thickness t2 may be within 2 to 3 times of the protrusion radius r1 and the groove radius r2.

Referring to FIGS. 3 to 6 , the inner circumferential surface 620 may include a protrusion 621 and a groove 622 . The inner circumferential surface 620 may have a concavo-convex shape in which protrusions 621 and grooves 622 are repeatedly arranged at regular intervals. Stress applied from the inside, in particular, stress in the circumferential direction may be dispersed by the uneven shape of the inner circumferential surface 620 .

The protrusion 621 may protrude toward the center of the gasket 600 . The protrusion 621 may protrude in a semicircular shape. The protrusion radius r1 may be 0.3 mm to 0.5 mm (see FIG. 4). If the radius r1 of the protrusion is less than 0.3 mm, it may be difficult to manufacture the gasket 600, and the shape of the inner circumferential surface 620 may not be uniform if precise processing is not performed. Accordingly, a place where stress is concentrated on the inner circumferential surface 620 may occur, and accordingly, the gasket 600 may be deformed and hydrogen may leak.

When the protrusion radius r1 exceeds 0.5 mm, the difference between the first thickness t1 and the second thickness t2 increases so that the stress of the inner circumferential surface 620 is not evenly offset, reducing the stress distribution effect. (See Figures 4 and 6). Therefore, the protrusion radius r1 may be 0.3 to 0.5 mm, preferably 0.4 mm.

The groove 622 is connected to the protrusion 621 and may be recessed in the opposite direction of the protrusion 621 . The groove 622 may be recessed in a semicircular shape. The groove radius r2 may be 0.3 mm to 0.5 mm (see FIG. 4). If the groove radius r2 is less than 0.3 mm, it may be difficult to manufacture the gasket 600, and if precise processing is not performed, the shape of the inner circumferential surface 620 may not be uniform. Accordingly, a place where stress is concentrated on the inner circumferential surface 620 may occur, and accordingly, the gasket 600 may be deformed and hydrogen may leak.

When the groove radius r2 exceeds 0.5 mm, the difference between the first thickness t1 and the second thickness t2 increases so that the stress of the inner circumferential surface 620 is not evenly offset, reducing the stress distribution effect. (See Figures 4 and 6). Accordingly, the groove radius r2 may be 0.3 mm to 0.5 mm, preferably 0.4 mm.

The protrusion radius r1 and the groove radius r2 may be the same. If the radius r1 of the protrusion and the radius r2 of the groove are not the same, a place where stress is concentrated may occur on the inner circumferential surface 620 and accordingly, the gasket 600 may be deformed and hydrogen may leak.

Hereinafter, the sealing effect of the gasket 600 according to an embodiment of the present invention will be described.

FIG. 7 is a diagram showing the outer strain according to the material of the gasket of FIG. 3 , and FIG. 8 is a diagram showing the outer strain according to the shape of the gasket of FIG. 3 .

Referring to FIG. 7 , when a pressure of 100 bar is applied to the gasket 600, FIG. 7(a) is a view showing strain distribution of the metal gasket. FIG. 7(b) is a diagram showing strain distribution of a Teflon (PTFE) gasket when a pressure of 100 bar is applied to the gasket 600. In the case of both the metal gasket and the Teflon gasket, it can be seen that the strain on the inner circumferential surface is the largest and the strain decreases toward the outer circumferential surface.

However, in the case of the metal gasket, since the elastic modulus is high and the Poisson's ratio is low, resistance to external force is high, so it can be confirmed that the deformation rate of the gasket 600 is small. In contrast, in the case of the Teflon gasket, since the elastic modulus is small and the Poisson's ratio is high, it can be confirmed that the resistance to external force is small and the deformation rate of the gasket 600 is large. Referring to the enlarged view of FIG. 7 (b), deformation occurs up to the vicinity of the outer periphery of the gasket 600, and wrinkles may occur because the strain is not uniform. Accordingly, the sealing effect of the gasket 600 is reduced, and there may be room for hydrogen to leak.

However, when a metal gasket is used, when a plurality of cells are laminated due to lack of elasticity, a gap is generated between the separator 400 and the membrane-electrode assembly 200 and the gasket 600 when a problem occurs in alignment. There is room for hydrogen to leak. Therefore, it is important to use a gasket made of a non-metallic elastic material with little room for a gap to occur between the separator 400 and the membrane-electrode assembly 200 and the gasket 600 even if there is a problem with alignment, and at the same time reduce strain.

Referring to FIG. 8, FIG. 8(a) is a diagram showing strain of a circular gasket when the same Teflon gasket as in FIG. 7(b) is used and a pressure of 100 bar is applied. FIG. 8(b) is a view showing the deformation rate of the concavo-convex gasket when the same Teflon gasket as in FIG. 7(b) is used and a pressure of 100 bar is applied.

In the concavo-convex gasket including the concavo-convex inner circumferential surface 620 of FIG. 8(b), as a result of stress being dispersed by the concavo-convex inner circumferential surface 620, deformation near the outer periphery of the gasket 600 is considerably reduced, and the entire gasket 600 Since the strain is uniform throughout, winkle may not occur. Therefore, in case of using the concave-convex gasket, even if the gasket 600 is made of a non-metallic elastic material, the sealing effect is reduced according to the external deformation of the gasket 600 and leakage of hydrogen can be prevented.

The coupling member 700 may include a bolt 710 and a nut 720 . The coupling member 700 may couple the end plates 100 at both ends through the through hole of the end plate 100 and provide fastening pressure. That is, a bolt 710 is inserted into the through hole of one end plate 100, and a nut 720 is inserted and coupled to the bolt 710 in the other end plate 100 to couple the end plates 100 at both ends. And tighten the nut 720 can adjust the clamping pressure. However, the coupling member 700 is not limited to the bolt 710 and the nut 720, and any configuration capable of coupling the end plates 100 at both ends may be possible.

Although one embodiment of the present invention has been described above, those skilled in the art can add, change, delete, or add components within the scope not departing from the spirit of the present invention described in the claims. The present invention can be variously modified and changed by the like, and this will also be said to be included within the scope of the present invention.

10 electrochemical hydrogen compressor
100 end plate
200 membrane-electrode assembly
300 gas diffusion layer
400 Separator
500 current collector
600 gasket
700 bonding member

Claims (8)

a membrane-electrode assembly including a cathode and an anode;
an anode-side separator disposed on the anode side to supply hydrogen to the anode;
a cathode-side separator disposed on the cathode side to discharge hydrogen from the cathode;
a pair of end plates respectively disposed on both ends of the anode-side separator and the cathode-side separator; and
a gasket disposed between the membrane-electrode assembly and the anode-side separator and the cathode-side separator to prevent hydrogen from leaking;
The gasket is a ring-shaped, electrochemical hydrogen compressor including an inner circumferential surface having irregularities. According to claim 1,
In the inner surface,
A protrusion protruding toward the center of the gasket and
An electrochemical hydrogen compressor connected to the protrusion, including a groove portion recessed in the opposite direction of the protrusion, wherein the protrusion and the groove portion are repeatedly arranged at equal intervals. According to claim 2,
The protruding portion and the groove portion are semicircular, electrochemical hydrogen compressor. According to claim 3,
The radius of the protrusion and the groove is 0.3mm ~ 0.5mm, electrochemical hydrogen compressor. According to claim 3,
The protruding portion and the groove portion have the same radius, an electrochemical hydrogen compressor. According to claim 4,
The gasket is
An electrochemical hydrogen compressor in which the first thickness, which is the maximum thickness of the gasket, is 10 to 20 times the radius. According to claim 6,
The gasket is
Electrochemical hydrogen compressor, wherein the difference between the second thickness, which is the minimum thickness of the gasket, and the first thickness is within 2 to 3 times the radius. According to claim 1,
The gasket is composed of a non-metallic elastic material, an electrochemical hydrogen compressor.

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