WO2024082129A1

WO2024082129A1 - Energy conversion unit and energy conversion device

Info

Publication number: WO2024082129A1
Application number: PCT/CN2022/125882
Authority: WO
Inventors: Ding Li; Jianfei WEI; Zhuan JI; Xin Liu; Qingfeng Yu
Original assignee: Schaeffler Technologies AG & Co. KG
Priority date: 2022-10-18
Filing date: 2022-10-18
Publication date: 2024-04-25

Abstract

Provided is an energy conversion unit including a first plate (1), a second plate (2), an elastic frame (3) and a membrane electrode assembly (4). The first plate (1) is spaced apart from the second plate (2), the elastic frame (3) may be made of elastic material such as rubber and formed into a ring shape, and may locate between the first plate (1) and the second plate (2). The elastic frame (3) may be formed with a plurality of first sealing protrusions (32) in contact with the first plate (1) and a plurality of second sealing protrusions (33) in contact with the second plate (2). Also provided is an energy conversion device including the above energy conversion unit, which may be a water electrolysis stack or a fuel cell stack.

Description

Energy conversion unit and energy conversion device

Technical Field

The present disclosure relates to energy conversion technology, in particular to an energy conversion unit and an energy conversion device including the energy conversion unit.

Background

Energy conversion devices typically include water electrolysis stack and fuel cell stack. In the water electrolysis stack, hydrogen and oxygen can be obtained by electrolyzing water; in the fuel cell stack, electrical energy is obtained by reacting of hydrogen and oxygen. Generally, a plurality of energy conversion units is included in the water electrolysis stack or the fuel cell stack, and the energy conversion unit is a key component of the water electrolysis stack or the fuel cell stack.

FIG. 1 illustrates a schematic cross-sectional view of a part of an energy conversion unit. The energy conversion unit comprises bipolar plates (afirst plate 10 and a second plate 20) , a frame 30, a membrane electrode assembly 40, gaskets 50 and a sealing ring 60. Whether in a water electrolysis stack or in a fuel cell stack, the membrane electrode assembly 40 is located in a space surrounded by the

bipolar plates

10, 20 and the frame 30. Further, hydrogen and oxygen would exist on both sides of a proton exchange membrane of the membrane electrode assembly 40, respectively, and the sealing ring 60 is provided between the frame 30 and the proton exchange membrane of the membrane electrode assembly 40 to prevent accidental mixing of hydrogen and oxygen. In addition, in order to prevent undesired leakage of hydrogen and oxygen to outside through gaps between the frame 30 and the

bipolar plates

10, 20, sealing between the frame 30 and the

bipolar plates

10, 20 is required. In the technical solution shown in FIG. 1, the frame 30 is provided with a plurality of sealing grooves to assemble the gaskets 50, and the gaskets 50 are used to realize the sealing between the frame 30 and the

bipolar plates

10, 20. However, pressure in the energy conversion unit is high, and thus the sealing achieved by the gaskets 50 suffers a risk of failure.

Summary

The present disclosure is made based on the above-mentioned state of the art. An object of the present disclosure is to provide an energy conversion unit for achieving good sealing between the bipolar plates and the frame with a relatively simple structure, which is less likely to fail even if the pressure in the energy conversion unit is high.

Another object of the present disclosure is to provide an energy conversion device including the above energy conversion unit.

This disclosure provides an energy conversion unit for generating hydrogen and oxygen by electrolysis of water or generating electricity energy by reaction of hydrogen and oxygen, comprising:

a first plate;

a second plate configured to be spaced apart from the first plate;

an elastic frame configured to be made of elastic material and formed into a ring shape, located between the first plate and the second plate, and formed with a plurality of first sealing protrusions in contact with the first plate and a plurality of second sealing protrusions in contact with the second plate; and

a membrane electrode assembly configured to be mounted in a mounting space surrounded by the first plate, the second plate and the elastic frame.

In one optional solution, each of the first sealing protrusions extends continuously over the entire circumference in a circumferential direction of the elastic frame; and each of the second sealing protrusions extends continuously over the entire circumference in the circumferential direction of the elastic frame.

In another one optional solution, the adjacent first sealing protrusions are arranged in parallel and spaced apart from each other; and/or the adjacent second sealing protrusions are arranged in parallel and spaced apart from each other.

In another one optional solution, the plurality of first sealing protrusions and the plurality of second sealing protrusions are symmetrically arranged with respect to a reference plane, which is perpendicular to a thickness direction of the energy conversion unit.

In another one optional solution, the elastic material comprises rubber or the elastic material is rubber.

In another one optional solution, the energy conversion unit further comprises an inlay, which is made of material with a rigidity or hardness greater than that of the elastic material of the elastic frame, and is embedded in the elastic frame.

In another one optional solution, the inlay is configured to be compressible in a thickness direction of the energy conversion unit.

In another one optional solution, the inlay is configured to extend continuously over the entire circumference in a circumferential direction of the elastic frame; or the inlay is configured to be arranged in sections in the circumferential direction of the elastic frame.

In another one optional solution, the inlay is Σ-shaped or wave-shaped in a cross section thereof.

In another one optional solution, the inlay comprises a first support plate, a second support plate and a connecting portion,

wherein the first support plate is in parallel to the first plate, the second support plate is in parallel to the second plate, and the first support plate and the second support plate is connected by the connecting portion, and the connecting portion extends from the first support plate to the second support plate and is bent relative to a thickness direction of the energy conversion unit.

In another one optional solution, the membrane electrode assembly comprises a first gas diffusion layer, a proton exchange membrane and a second gas diffusion layer,

wherein the first gas diffusion layer is located between the proton exchange membrane and the first plate, and the second gas diffusion layer is located between the proton exchange membrane and the second plate, wherein a part of the first gas diffusion layer and the elastic frame are integrally formed to separate the mounting space into a first part and a second part, another part of the first gas diffusion layer are located in the first part of the mounting space, and the proton exchange membrane and the second gas diffusion layer are located in the second part of the mounting space.

In another one optional solution, the first gas diffusion layer comprises a first conductor layer, wherein the first conductor layer comprises a central portion and an outer peripheral portion fixed to each other, the outer peripheral portion being located on an outer periphery of the central portion and being embedded in the elastic frame, and

the elastic frame has a support portion, wherein the support portion is overlapped with the outer peripheral portion in a thickness direction of the energy conversion unit, and the proton exchange membrane is pressed against the central portion and the support portion.

In another one optional solution, in case that the elastic material comprises rubber or the elastic material is rubber, the support portion and the outer peripheral portion are formed integrally by vulcanization molding.

In another one optional solution, the support portion has a first support surface for supporting the proton exchange membrane, and the central portion has a second support surface for supporting the proton exchange membrane, wherein before the proton exchange membrane is pressed against the central portion and the support portion, the first support surface protrudes towards the proton exchange membrane relative to the second support surface.

This disclosure further provides an energy conversion unit for generating hydrogen and oxygen by electrolysis of water or generating electricity energy by reaction of hydrogen and oxygen, comprising:

a first plate;

a second plate configured to be spaced apart from the first plate;

an elastic frame configured to be made of rubber and formed into a ring shape, located between the first plate and the second plate, and being in contact with the first plate and the second plate; and

In one optional solution, the membrane electrode assembly comprises a first gas diffusion layer, a proton exchange membrane and a second gas diffusion layer, wherein the first gas diffusion layer is located between the proton exchange membrane and the first plate, and the second gas diffusion layer is located between the proton exchange membrane and the second plate,

wherein a part of the first gas diffusion layer is integrally formed with the elastic frame to separate the mounting space into two parts.

This disclosure further provides an energy conversion device comprising at least one energy conversion unit according to any one of the above-mentioned solutions.

In one optional solution, the energy conversion device is a water electrolysis stack.

By adopting the above technical solutions, the present disclosure provides an energy conversion unit and an energy conversion device including the energy conversion unit. In the energy conversion unit, an elastic frame between bipolar plates (afirst plate and a second plate) may be made of an elastic material such as rubber and formed in a ring shape. In this way, a good sealing effect is achieved between the bipolar plates and the elastic frame with a relatively simple structure. Therefore, even if the pressure in the energy conversion unit is high, the sealing between the bipolar plates and the elastic frame is less likely to fail.

In at least one optional solution, one side surface of the elastic frame is formed with a plurality of first sealing protrusions that are in contact with the first plate and the other side surface of the elastic frame is formed with a plurality of second sealing protrusions that are in contact with the second plate. In this way, by arranging a plurality of first sealing protrusions and a plurality of second sealing protrusions on the elastic frame, a larger contact area and more sealing locations can be easily realized between the plurality of sealing protrusions and the bipolar plates, so that the sealing between the bipolar plates and the elastic frame is less likely to fail, even if the pressure in the energy conversion unit is high.

Brief Introduction of the Drawings

FIG. 1 is a schematic partial cross-sectional view illustrating an energy conversion unit.

FIG. 2 is a schematic partial cross-sectional view illustrating an energy conversion unit according to a first example of the present disclosure.

FIG. 3 is a schematic partial cross-sectional view illustrating an energy conversion unit according to a second example of the present disclosure.

FIG. 4A is a schematic partial cross-sectional view illustrating an energy conversion unit according to a third example of the present disclosure.

FIG. 4B is a schematic cross-sectional view illustrating a combination of an elastic frame and a first conductor layer of the energy conversion unit in FIG. 4A.

FIG. 4C is a schematic stereogram view illustrating the combination of the elastic frame and the first conductor layer of the energy conversion unit in FIG. 4A.

FIG. 4D is a schematic cross-sectional view illustrating a part of the combination in FIGs. 4B and 4C.

FIG. 5 is a schematic stereogram view illustrating an energy conversion device according to an example of the present disclosure.

List of Reference Signs

10 first plate; 20 second plate; 30 frame; 40 membrane electrode assembly; 50 gasket; 60 sealing ring;

1 first plate;

2 second plate;

3 elastic frame; 31 frame body; 32 first sealing protrusion; 33 second sealing protrusion; 34 supporting portion; 34s first supporting surface;

4 membrane electrode assembly; 41 first gas diffusion layer; 411 first conductor layer; 4111 central portion; 4111s second support surface; 4112 outer peripheral portion; 412 first porous layer; 42 proton exchange membrane; 43 second gas diffusion layer; 431 second conductor layer; 432 second porous layer;

5 frame; 51 first support plate; 52 second support plate; 53 connecting portion;

6 sealing ring;

T thickness direction;

L reference plane;

C energy conversion unit;

E end plate;

B connector.

Detailed Embodiments

Examples of the present disclosure will be described in details below with reference to the accompanying drawings. It should be understood that these specific descriptions are only used to teach those skilled in the art how to implement the present disclosure, but not used to exhaust all possibilities of the present disclosure, or to limit the scope of the present disclosure.

In the present disclosure, unless otherwise specified, a thickness direction refers to the thickness direction of the energy conversion unit. "One side in the thickness direction" refers to a lower side in FIGs. 2, 3, 4A, 4B, and 4D, and "the other side in the thickness direction" refers to an upper side in FIGs. 2, 3, 4A, 4B, and 4D.

In the present disclosure, a "ring shape" does not refer to a circular ring shape in particular, but may be other ring shapes such as a rectangular ring shape.

The structure of the energy conversion unit according to the first example of the present disclosure will be described below with reference to the accompanying drawings.

(Energy conversion unit according to the first example of the present disclosure)

The energy conversion unit according to the first example of the present disclosure may be used to generate hydrogen and oxygen by electrolyzing water. As shown in FIG. 2, the energy conversion unit C comprises bipolar plates (afirst plate 1 and a second plate 2) , an elastic frame 3, a membrane electrode assembly 4 and a sealing ring 6 assembled together.

In the present example, the first plate 1 may be made of a conductive material such as a carbonaceous material, a metal material, or a composite material.

In the present example, the second plate 2 may be made of a conductive material such as a carbonaceous material, a metal material, or a composite material. As shown in FIG. 2, the second plate 2 and the first plate 1 are arranged parallel to each other and spaced apart in the thickness direction T.

It could be understood that the outer peripheral portions of the first plate 1 and the second plate 2 (for example, the left portions in FIG. 2) may be flat. In addition, for example, center portions of the first plate 1 and the second plate 2 may be formed with a plurality of grooves.

In the present example, the elastic frame 3 may be made of an elastic material such as rubber and formed in a ring shape. As shown in FIG. 2, the elastic frame 3 is located between the first plate 1 and the second plate 2 in the thickness direction T and achieves contact sealing with the first plate 1 and the second plate 2. Specifically, the elastic frame 3 comprises a frame body 31, a plurality of first sealing protrusions 32 and a plurality of second sealing protrusions 33 formed as one piece. The plurality of first sealing protrusions 32 are formed on the surface of the frame body 31 on one side in the thickness direction T, and the plurality of second sealing protrusions 33 are formed on the surface of the frame body 31 on the other side in the thickness direction T.

The frame body 31 may be solid and may be formed in a rectangular ring shape, and the frame body 31 continuously extends in the circumferential direction of the elastic frame 3. As a result, a mounting space is formed and surrounded by the first plate 1, the second plate 2 and the elastic frame 3 (the frame body 31) .

The plurality of first sealing protrusions 32 protrude toward the first plate 1 with respect to the surface of the frame body 31 on the one side in the thickness direction T, and the plurality of first sealing protrusions 32 are in contact with the first plate 1. Each of the first sealing protrusions 32 may extend continuously over the entire circumference in the circumferential direction of the elastic frame 3. That is, the first sealing protrusion 32 may be a sealing strip extending along the circumferential direction of the elastic frame 3. The adjacent first sealing protrusions 32 may be arranged in parallel and spaced apart from each other. In the cross-sectional view shown in FIG. 2, each of the first sealing protrusions 32 has an arc-shaped outer contour. After the first sealing protrusions 32 are pressed into contact with the first plate 1, the top ends of the first sealing protrusions 32 are pressed flat by the first plate 1 due to the characteristic of the elastic material, so that there are sufficiently large contact areas between the first sealing protrusions 32 with flattened top ends and the first plate 1. In this way, the sealing effect between the first sealing protrusions 32 (elastic frame 3) and the first plate 1 is improved. The hydrogen and oxygen generated at the membrane electrode assembly 4 can be enclosed in the mounting space surrounded by the first plate 1, the second plate 2 and the elastic frame 3.

The plurality of second sealing protrusions 33 protrude toward the second plate 2 with respect to the surface of the frame body 31 on the other side in the thickness direction T, and the plurality of second sealing protrusions 33 are in contact with the second plate 2. Each of the second sealing protrusions 33 may extend continuously over the entire circumference in the circumferential direction of the elastic frame 3. That is, the second sealing protrusion 33 may be a sealing strip extending along the circumferential direction of the elastic frame 3. The adjacent second sealing protrusions 33 may be arranged in parallel and spaced apart from each other. In the sectional view shown in FIG. 2, each of the second sealing protrusion 33 has an arc-shaped outer contour. After the second sealing protrusions 33 are pressed into contact with the second plate 2, the top ends of the second sealing protrusions 33 are pressed flat by the second plate 2 due to the characteristic of the elastic material, so that there are sufficiently large contact areas between the second sealing protrusion 33 with flattened top ends and the second plate 2. In this way, the sealing effect between the second sealing protrusions 33 (elastic frame 3) and the second plate 2 is improved. The hydrogen and oxygen generated at the membrane electrode assembly 4 can be enclosed in the mounting space surrounded by the first plate 1, the second plate 2 and the elastic frame 3.

Further, in this example, in order to make the elastic frame 3 deform in the substantially same extent and the stress is basically equal on both sides of the elastic frame 3 in the thickness direction T under the state of contact sealing between the first plate 1, the second plate 2 and the elastic frame 3, there is a reference plane L perpendicular to the thickness direction T of the energy conversion unit C (the dotted line in FIG. 2 indicates the position of the reference plane L in the cross-sectional view) , the plurality of first sealing protrusions 32 and the plurality of second sealing protrusions 33 may be arranged symmetrically with respect to the reference plane L. That is, for the first sealing protrusions 32 and the second sealing protrusions 33, the number and the size are the same, the shapes are symmetrical, and the arrangement positions are corresponding. It could be understood that the reference plane L coincides with the central plane of the frame body 31 in the thickness direction T.

In this example, as shown in FIG. 2, the membrane electrode assembly 4 is mounted in the mounting space surrounded by the first plate 1, the second plate 2 and the elastic frame 3 (frame body 31) . The membrane electrode assembly 4 may comprise a first gas diffusion layer 41, a proton exchange membrane (both surfaces of which may be directly coated with catalyst) 42 and a second gas diffusion layer 43. The first gas diffusion layer 41 is located between the proton exchange membrane 42 and the first plate 1, and the second gas diffusion layer 43 is located between the proton exchange membrane 42 and the second plate 2. The first gas diffusion layer 41 may comprise a first conductor layer 411 and a first porous layer 412, wherein the first conductor layer 411 is located between the first porous layer 412 and the proton exchange membrane 42. In this example, the first conductor layer 411 may be a Ti (titanium) -felt, and the first porous layer 412 may be a Ti-web.

The second gas diffusion layer 43 may comprise a second conductor layer 431 and a second porous layer 432, the second conductor layer 431 is located between the second porous layer 432 and the proton exchange membrane 42. In this example, the second conductor layer 431 may be carbon paper, and the second porous layer 432 may be steel web. In this way, oxygen can be generated on the anode side of the proton exchange membrane 42 (where the first plate 1 is located) and hydrogen can be generated on the cathode side (where the second plate 2 is located) by the water electrolysis occurring on the membrane electrode assembly 4, and the oxygen and hydrogen thus generated can flow out of the energy conversion unit C through predetermined paths to be collected.

In this example, the sealing ring 6 is located in a mounting groove formed by the frame body 31 and is located between the frame body 31 and the proton exchange membrane 42, for preventing the anode side and the cathode side of the proton exchange membrane 42 from communicating which brings the mixture of the hydrogen and oxygen.

By adopting the above technical solution, in the energy conversion unit C of the present disclosure, the sealing between the

bipolar plates

1, 2 and the elastic frame 3 can be realized with a relatively simple structure. Provision of the sealing

protrusions

32, 33, sealing parts are formed and the contact areas between the

bipolar plates

1 and 2 and the sealing

protrusions

32, 33 are large, so the sealing effect is better than the one realized by the gaskets 50 in FIG. 1, the structure of the energy conversion unit C is relatively simplified and the corresponding cost are reduced since the gaskets 50 are omitted.

The structure of the energy conversion unit C according to the second example of the present disclosure will be described below with reference to the accompanying drawings.

(Energy conversion unit according to the second example of the present disclosure)

Some aspects or features of the energy conversion unit C according to the second example of the present disclosure are the same or similar to those of the energy conversion unit C according to the first example of the present disclosure, the difference (s) from each other will be described.

As shown in FIG. 3, the energy conversion unit C according to the second example of the present disclosure further comprises an inlay 5. The inlay 5 may be made of a rigid material such as spring steel and embedded in the frame body 31 of the elastic frame 3. Herein, the rigidity or hardness of the rigid material may be higher than the rigidity or hardness of the elastic material used to make the elastic frame 3. For example, in addition to spring steel, the rigid material may also be other metals or plastics.

Specifically, the cross section of the inlay 5 is formed in a Σ-shape. The inlay 5 comprises a first support plate 51, a second support plate 52 and a connecting portion 53 formed as one piece. The first support plate 51 is parallel to the first plate 1, the second support plate 52 is parallel to the second plate 2, the first support plate 51 is closer to the first plate 1, and the second support plate 52 is closer to the second plate 2. The connecting portion 53 is formed in a curved plate shape, the connecting portion 53 is connected to the outer end edges of both the first support plate 51 and the second support plate 52, and the connecting portion 53 extends from the first support plate 51 to the second support plate 52 and is bent with respect to the thickness direction T of the energy conversion unit C. In this way, not only a better supporting effect is provided by the inlay 5, but also the ability of the inlay 5 to generate a certain elastic deformation in the thickness direction T is achieved. Further, in order to enable the inlay 5 to provide a sufficient supporting effect, in this example, the inlay 5 extends continuously over the entire circumference in the circumferential direction of the elastic frame 3. The inlay 5 can be, but does not have to be, a closed ring shape. Herein, two ends of an inlay 5 may be connected fixedly or overlapped with each other to form a ring shape, or a small gap may exist between two ends of the inlay 5.

The energy conversion unit C according to the second example of the present disclosure has the same technical effect as the energy conversion unit C according to the first example of the present disclosure. Further, the material of the frame 30 of the energy conversion unit as shown in FIG. 1 is poly ether ether Ketone (PEEK) . The creep performance of PEEK is not good, the compression deformation of PEEK is very high once the energy conversion unit works for a long time, the frame 30 will lose elasticity and cannot provide sufficient force for the gaskets 50, resulting in sealing failure. In contrast, in the second example of the present disclosure, the elastic frame 3 may be made of elastic material, for example rubber. It has better elastic property and creep resistance in rubber than in poly ether ether Ketone, but with lower cost. Moreover, since the inlay 5 is provided in the frame body 31 of the elastic frame 3, excessive compression of the elastic frame 3 can be avoided, thereby preventing the sealing performance of the elastic frame 3 from being affected, and it can also improve the creep performance of the elastic frame 3 by the inlay 5.

The structure of the energy conversion unit C according to the third example of the present disclosure will be described below with reference to the accompanying drawings.

(Energy conversion unit according to the third example of the present disclosure)

Some aspects or features of the energy conversion unit C according to the third example of the present disclosure are the same or similar to some aspects or features of the energy conversion unit C according to the first example of the present disclosure, the difference (s) from each other will be described.

As shown in FIG. 4A, the first conductor layer 411 of the first gas diffusion layer 41 comprises a central portion 4111 and an outer peripheral portion 4112 formed as one piece. The outer peripheral portion 4112 is located on the outer periphery of the central portion 4111 and is entirely embedded in the elastic frame 3, and the outer peripheral portion 4112 is the part of the first gas diffusion layer 41 that is integrally formed with the elastic frame 3. The thickness of the outer peripheral portion 4112 may be smaller than that of the central portion 4111, thereby forming a step structure at the connection portion of the outer peripheral portion 4112 and the central portion 4111. With the above structure, the mounting space surrounded by the first plate 1, the second plate 2 and the elastic frame 3 is divided into a first part and a second part, and the first porous layer 412 of the first gas diffusion layer 41 is the another part which is located on one side of the first conductor layer 411 in the thickness direction T and is accommodated in the first part of the mounting space. The proton exchange membrane 42 and the second gas diffusion layer 43 are located on the other side of the first conductor layer 411 in the thickness direction T and are accommodated in the second part of the mounting space.

Further, as shown in FIGs. 4A to 4D, the elastic frame 3 has a support portion 34 overlapped with the outer peripheral portion 4112 in the thickness direction T, and the support portion 34 has a first support surface 34s. The central portion 4111 of the first conductor layer 411 has a second support surface 4111s. The proton exchange membrane 42 is supported by the first support surface 34s and the second support surface 4111s, and the proton exchange membrane 42 is pressed against the first support surface 34s and the second support surface 4111s. Also, in a state where the proton exchange membrane 42 is not pressed against the first support surface 34s of the support portion 34 and the second support surface 4111s of the central portion 4111, the first support surface 34s of the support portion 34 protrudes toward the proton exchange membrane 42 with respect to the second support surface 4111s of the central portion 4111. In this way, since the support portion 34 is made of an elastic material, in a state where the proton exchange membrane 42 is pressed against the first support surface 34s of the support portion 34 and the second support surface 4111s of the central portion 4111, a good sealing effect between the support portion 34 and the proton exchange membrane 42 is achieved by the force generated from the deformation of the support portion 34 under pressure. Thereby, the two sides of the proton exchange membrane 42 in the thickness direction T can be prevented from communicating with each other. Furthermore, in the present example, the sealing ring 6 described in the first and second examples is omitted, thereby reducing the number of parts, simplifying the structure of the energy conversion unit C and reducing the cost.

The structure of the energy conversion device according to an example of the present disclosure will be described below with reference to the accompanying drawings.

(Energy conversion device according to an example of the present disclosure)

As shown in FIG. 5, an energy conversion device according to an example of the present disclosure comprises two end plates E, a plurality of connectors B, and a plurality of energy conversion units C described above. The plurality of energy conversion units C are stacked on each other. The two end plates E are located at both sides of the combination formed by the plurality of energy conversion units C, and the entire energy conversion device can be assembled through the plurality of connectors B. In this example, the energy conversion device may be a water electrolysis stack.

Examples according to the present disclosure have been described in details above, and supplementary descriptions are provided below.

i. The example of the energy conversion device of the present disclosure is not limited to the water electrolysis stack described in the above detailed description, but may also be a fuel cell stack. In a fuel cell stack, hydrogen and oxygen are provided to react, so as to generate electricity energy and produce water. In addition, the number of energy conversion units in the energy conversion device according to the present disclosure can be adjusted as required, as long as at least one energy conversion unit is included.

ii. In the above example, it is explained that each of the sealing

protrusions

32, 33 extends continuously in the circumferential direction of the elastic frame 3, but the present disclosure is not limited thereto. In an optional solution, a plurality of first sealing protrusions 32 are arranged in a manner of intersecting with each other to form a grid shape as a whole, so that at least a part of the first sealing protrusions 32 does not have to be continuous on the entire circumference in the circumferential direction of the elastic frame 3, even the first sealing protrusions 32 do not have to extend in the circumferential direction of the elastic frame 3. The second sealing protrusions 32 may also be arranged in a similar manner.

In the above second example, it was explained that the inlay 5 is configured to extend continuously in the circumferential direction of the elastic frame 3, but the present disclosure is not limited thereto. The inlay 5 may be configured to be arranged in sections in the circumferential direction of the elastic frame 3, but the interval between two adjacent sections may be set small, so that the inlay 5 can indeed achieve the effects described in the above examples.

Further, in other optional solutions, the inlay 5 can adopt other shapes, as long as the inlay 5 can not only provide a certain support function but also have a structure that can be elastically compressed in the thickness direction T (that is, the inlay 5 is configured to be able to be compressed in the thickness direction T to generate elastic deformation) . For example, the inlay 5 may be configured to have a wavy cross-sectional shape including a plurality of crests protruding toward the first plate 2 and a plurality of troughs protruding toward the second plate 3. It could be understood that the wave shape can not only provide a certain supporting effect to the elastic frame 3, but also can produce elastic deformation under the force in the thickness direction T.

iii. In the energy conversion unit shown in FIG. 1, there is a gap between the frame 30 and the conductor layer of the membrane electrode assembly 40. When the force applied to the proton exchange membrane of the membrane electrode assembly 40 is large, the proton exchange membrane may break at this gap. For example, in a water electrolysis stack, the pressure on the hydrogen side (upper side in Figure 1) is significantly higher (the pressure difference may be several MPa) than the pressure on the oxygen side (lower side in Figure 1) , the proton exchange membrane (maybe only a few hundred microns thick) would be compressed into this gap, deforming greatly and possibly broken. As such, mixing of hydrogen and oxygen through the break may result, which is undesirable. By adopting the solution of the above-mentioned third example, the first conductor layer 411 of the membrane electrode assembly 4 in the energy conversion unit C of the present disclosure is integrated with the elastic frame 3, thus the above-mentioned gap is removed from the structure, thus eliminating the risk that the proton exchange membrane 42 will be damaged due to the presence of the gap.

iv. It could be understood that in the case where the elastic frame 3 is made of rubber, the elastic frame 3 can be formed integrally with the first conductor layer 411 by vulcanization molding, namely the support portion 34 and the outer peripheral portion 4112 can be formed integrally by vulcanization molding. During the vulcanization molding process, an adhesive may be coated on the surface of the first conductor layer 411 to improve the bonding strength between the elastic frame 3 and the first conductor layer 411. Furthermore, it is possible to further prevent the hydrogen and the oxygen from being mixed via the gap between the elastic frame 3 and the first conductor layer 411.

v. In an optional solution, in the case that the elastic frame 3 is made of rubber, there are not any

elastic protrusion

32, 33 described in the above examples on the surfaces of the frame body 31 of the elastic frame 3 on both sides in the thickness direction T, but the surfaces of the frame body 31 of the elastic frame 3 on both sides in the thickness direction T can be in direct contact with the first plate 1 and the second plate 2 to achieve sealing.

Claims

An energy conversion unit for generating hydrogen and oxygen by electrolysis of water or generating electricity energy by reaction of hydrogen and oxygen, comprising:

a first plate (1) ;

a second plate (2) configured to be spaced apart from the first plate (1) ;

an elastic frame (3) configured to be made of elastic material and formed into a ring shape, located between the first plate (1) and the second plate (2) , and formed with a plurality of first sealing protrusions (32) in contact with the first plate (1) and a plurality of second sealing protrusions (33) in contact with the second plate (2) ; and

a membrane electrode assembly (4) configured to be mounted in a mounting space surrounded by the first plate (1) , the second plate (2) and the elastic frame (3) .
The energy conversion unit according to claim 1, wherein

each of the first sealing protrusions (32) extends continuously over the entire circumference in a circumferential direction of the elastic frame (3) ; and

each of the second sealing protrusions (33) extends continuously over the entire circumference in the circumferential direction of the elastic frame (3) .
The energy conversion unit according to claim 1, wherein

the adjacent first sealing protrusions (32) are arranged in parallel and spaced apart from each other; and/or

the adjacent second sealing protrusions (33) are arranged in parallel and spaced apart from each other.
The energy conversion unit according to any one of claims 1 to 3, wherein

the plurality of first sealing protrusions (32) and the plurality of second sealing protrusions (33) are symmetrically arranged with respect to a reference plane (L) , which is perpendicular to a thickness direction (T) of the energy conversion unit (C) .
The energy conversion unit according to any one of claims 1 to 4, wherein the elastic material comprises rubber or the elastic material is rubber.
The energy conversion unit according to any one of claims 1 to 5, further comprising an inlay (5) , which is made of material with a rigidity or hardness greater than that of the elastic material of the elastic frame (3) , and is embedded in the elastic frame (3) .
The energy conversion unit according to claim 6, wherein

the inlay (5) is configured to be compressible in a thickness direction (T) of the energy conversion unit (C) .
The energy conversion unit according to claim 6 or 7, wherein

the inlay (5) is configured to extend continuously over the entire circumference in a circumferential direction of the elastic frame (3) ; or

the inlay (5) is configured to be arranged in sections in the circumferential direction of the elastic frame (3) .
The energy conversion unit according to any one of claims 6 to 8, wherein the inlay (5) is Σ-shaped or wave-shaped in a cross section thereof.
The energy conversion unit according to any one of claims 6 to 9, wherein the inlay (5) comprises a first support plate (51) , a second support plate (52) and a connecting portion (53) ,

wherein the first support plate (51) is in parallel to the first plate (1) , the second support plate (52) is in parallel to the second plate (2) , and the first support plate (51) and the second support plate (52) is connected by the connecting portion (53) , and the connecting portion (53) extends from the first support plate (51) to the second support plate (52) and is bent relative to a thickness direction (T) of the energy conversion unit (C) .
The energy conversion unit according to any one of claims 1 to 10, wherein the membrane electrode assembly (4) comprises a first gas diffusion layer (41) , a proton exchange membrane (42) and a second gas diffusion layer (43) ,

wherein the first gas diffusion layer (41) is located between the proton exchange membrane (42) and the first plate (1) , and the second gas diffusion layer (43) is located between the proton exchange membrane (42) and the second plate (2) , wherein a part of the first gas diffusion layer (41) and the elastic frame (3) are integrally formed to separate the mounting space into a first part and a second part, another part of the first gas diffusion layer (41) are located in the first part of the mounting space, and the proton exchange membrane (42) and the second gas diffusion layer (43) are located in the second part of the mounting space.
The energy conversion unit according to claim 11, wherein

the first gas diffusion layer (41) comprises a first conductor layer (411) , wherein the first conductor layer (411) comprises a central portion (4111) and an outer peripheral portion (4112) fixed to each other, the outer peripheral portion (4112) being located on an outer periphery of the central portion (4111) and being embedded in the elastic frame (3) , and

the elastic frame (3) has a support portion (34) , wherein the support portion (34) is overlapped with the outer peripheral portion (4112) in a thickness direction (T) of the energy conversion unit (C) , and the proton exchange membrane (42) is pressed against the central portion (4111) and the support portion (34) .
The energy conversion unit according to claim 12, wherein in case that the elastic material comprises rubber or the elastic material is rubber, the support portion (34) and the outer peripheral portion (4112) are formed integrally by vulcanization molding.
The energy conversion unit according to claim 12 or 13, wherein the support portion (34) has a first support surface (34s) for supporting the proton exchange membrane (42) , and the central portion (4111) has a second support surface (4111s) for supporting the proton exchange membrane (42) , wherein before the proton exchange membrane (42) is pressed against the central portion (4111) and the support portion (34) , the first support surface (34s) protrudes towards the proton exchange membrane (42) relative to the second support surface (4111s) .
An energy conversion device comprising at least one energy conversion unit (C) according to any one of claims 1 to 14.
The energy conversion device according to claim 15, wherein the energy conversion device is a water electrolysis stack.