Electrochemical cell and electrochemical device

Abstract

An electrochemical cell and an electrochemical device. The electrochemical cell comprises an electrochemical cell frame (1), a membrane electrode (2), and a sealing member (3). The membrane electrode (2) is arranged in an accommodating space on the inner peripheral side of the electrochemical cell frame (1); and the sealing member (3) is arranged between the electrochemical cell frame (1) and the membrane electrode (2). The membrane electrode (2) comprises at least one stacked unit arranged in a stacked manner, and a gap is formed between the at least one stacked unit and the electrochemical cell frame (1). The sealing member (3) comprises a lip portion (32), and the lip portion (32) extends into the gap in the thickness direction of the electrochemical cell. The sealing member is provided with the lip portion, so that the sealing member can be used for sealing and can also provide a compression connection for the stacked unit and the electrochemical cell frame. The sealing member has good sealing performance, so that the components of the membrane electrode are better stacked, and the sealing member is easy to manufacture and has low costs.

Description

Electrochemical units and electrochemical devices Technical Field

[0001] This invention relates to the field of sealing technology for electrochemical devices. Specifically, this invention relates to an electrochemical unit and an electrochemical device. Background Technology

[0002] Electrochemical devices can include, but are not limited to, batteries. For example, in proton exchange membrane electrolyzers (PEMWE) and proton exchange membrane fuel cells (PEMFC), electrochemical devices include electrochemical unit groups, which consist of multiple electrochemical units stacked together. Each electrochemical unit includes an electrochemical unit frame and its internal membrane electrode assembly (MEA). For example, in a water electrolyzer, ultrapure water is introduced as the initial material at the anode side of the MEA, and the ultrapure water is dissociated into hydrogen and oxygen within the proton exchange membrane (PEM). Specifically, the ultrapure water is dissociated into oxygen at the anode, and protons recombine to form hydrogen at the cathode side after passing through the proton exchange membrane. The electrochemical unit frame is disposed on the outer periphery of the MEA for assembling, fixing, and sealing the MEA.

[0003] The membrane electrode assembly (MEA) comprises a porous transport layer (PTL) and a proton exchange layer (PEM), with the catalyst coated onto the PEM to form a catalyst-coated membrane (CCM). When placing the PTL, if the size of the porous transport layer is larger than the size of the space within the electrochemical unit frame, the PTL cannot be placed within that space. Therefore, in related technologies, the size of the PTL is smaller than the size of the space, resulting in a gap between the PTL and the electrochemical unit frame. This gap easily leads to slippage of the CCM within the MEA, potentially causing damage to the seal due to large sliding displacement. This, in turn, can damage the proton exchange layer within the MEA, ultimately leading to seal failure and leakage. Therefore, it is necessary to address these issues. Summary of the Invention

[0004] To address the above technical problems, the present invention provides an electrochemical unit and an electrochemical device, wherein the electrochemical device may be, but is not limited to, PEMWE and PEMFC.

[0005] In a first aspect, embodiments of the present invention provide an electrochemical unit, including an electrochemical unit frame, a membrane electrode, and a sealing member. The membrane electrode is disposed within a receiving space in the electrochemical unit frame. The sealing member is disposed between the electrochemical unit frame and the membrane electrode. The membrane electrode includes a PTL, a CCM, and a PEM stacked together, with a gap between the PTL and the electrochemical unit frame. The sealing member includes a lip extending along the thickness direction of the electrochemical unit into the gap.

[0006] According to an optional embodiment of the present invention, a flow channel is provided on one side of the electrochemical unit frame in the thickness direction, and the extension of the lip in the thickness direction does not enter the flow channel.

[0007] According to an optional embodiment of the present invention, the electrochemical unit frame includes a support platform extending toward the inner peripheral side, and the outer peripheral portion of the membrane electrode is disposed on the support platform. The seal includes a body portion disposed between the support platform and the outer peripheral portion of the membrane electrode, and the lip is formed by extending along the thickness direction from the inner peripheral edge of the body portion.

[0008] According to an optional embodiment of the invention, the seal is formed on the support platform by a vulcanization process.

[0009] According to an optional embodiment of the invention, the thickness of the main body is variable.

[0010] According to an optional embodiment of the present invention, the main body has a wavy surface with varying heights on the side opposite to the support platform 12 in the thickness direction.

[0011] According to an optional embodiment of the invention, the seal 3 is made of a superelastic material.

[0012] According to an optional embodiment of the invention, the seal is made of rubber material.

[0013] According to an optional embodiment of the present invention, the at least one stacked unit includes a porous transport layer and a proton exchange layer, the porous transport layer having a gap with the electrochemical unit frame, and the lip extending into the gap along the thickness direction of the electrochemical unit.

[0014] Embodiments of the present invention also provide an electrochemical device, comprising: an electrochemical unit group and two end plates. The electrochemical unit group includes a plurality of electrochemical units as described in any one of the above embodiments, stacked together. The two end plates are respectively disposed at both ends of the stacking direction of the electrochemical unit group.

[0015] By incorporating a lip into the seal, it serves both as a seal and as a compression connection for the PTL and electrochemical unit frame. This seal provides excellent sealing performance, allowing for better stacking of the membrane electrode components, and is easy to manufacture and cost-effective.

[0016] Furthermore, by setting the surface of the main body on the side away from the support platform in the thickness direction to a wave-like shape with varying heights, the high pressure resistance of the seal can be improved, and the seal can achieve self-sealing. That is, in the thickness direction, the greater the pressure on the seal, the better the sealing effect. Attached Figure Description

[0017] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments of the present invention will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 shows a decomposition and explosion diagram of an electrochemical device according to an embodiment of the present invention;

[0019] Figure 2 shows a partial cross-sectional view of an electrochemical unit according to an embodiment of the present invention;

[0020] Figure 3 shows a partial perspective view of a portion of the structure of an electrochemical unit according to an embodiment of the present invention;

[0021] Figure 4 shows a partial perspective view of a portion of the structure in an electrochemical unit according to an embodiment of the present invention; and

[0022] Figure 5 shows a partial perspective view of a seal according to an embodiment of the present invention. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of the embodiments of this disclosure clearer, the technical solutions of the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the described embodiments of this invention are within the scope of protection of this invention.

[0024] Figure 1 shows an exploded view of an electrochemical device according to an embodiment of the present invention; Figure 2 shows a schematic diagram of an electrochemical unit 100 according to an embodiment of the present invention. The electrochemical device can be a fuel cell, a water electrolysis cell, or other types of battery, and is not limited thereto. Referring to Figures 1 and 2, for example in a proton exchange membrane water electrolysis cell (PEMWE) and a proton exchange membrane fuel cell (PEMFC), the electrochemical device includes an electrochemical unit group 1000 and two end plates 2000 respectively disposed at both ends of the stacking direction of the electrochemical unit group 1000. The electrochemical unit group 1000 can be referred to as an electrolyzer in a PEMWE and as a stack in a PEMFC.

[0025] The electrochemical unit group 1000 includes a plurality of electrochemical units 100 stacked together. Each electrochemical unit 100 includes an electrochemical unit frame 1 and a membrane electrode 2 disposed in a receiving space on the inner periphery of the electrochemical unit frame 1. The membrane electrode 2 includes at least one stacked unit. For example, in a proton exchange membrane battery, the stacked unit may include a porous transport layer (PTL) 21 and a proton exchange layer (PEM), wherein the membrane assembly after coating the PEM with a catalyst forms a catalyst coated membrane (CCM). The electrochemical unit frame 1 is used to mount and fix the membrane electrode 2. The electrochemical unit frame 1 is provided with manifold openings and flow channels 11 communicating between the manifold openings and the receiving space inside the electrochemical unit frame 1. When the plurality of electrochemical units 100 are stacked together, the plurality of manifold openings of the plurality of electrochemical units 100 communicate in the thickness direction to form a manifold. The flow channel 11 more specifically communicates between the manifold and the PTL 21 of the membrane electrode 2 within the receiving space. A sealing element 3 is required between the electrochemical unit frame 1 and the membrane electrode 2, particularly between the electrochemical unit frame 1 and the PTL 21, to prevent hydrogen and oxygen from leaking into other layers of the membrane electrode 2. This invention provides an electrochemical unit frame 1 with a sealing element that offers better sealing and assembly performance.

[0026] According to embodiments of the present invention, an electrochemical unit 100 is provided, which is applied in an electrochemical device, particularly in PEMWE and PEMFC.

[0027] Figure 3 shows a partial perspective view of a portion of the structure of the electrochemical unit 100 according to an embodiment of the present invention; Figure 4 shows a partial perspective view of another view of a portion of the structure of the electrochemical unit 100 according to an embodiment of the present invention; and Figure 5 shows a partial perspective view of the seal 3 according to an embodiment of the present invention. Referring to Figures 2 to 5, the electrochemical unit 100 includes an electrochemical unit frame 1, a membrane electrode 2, and a seal 3. The membrane electrode 2 is disposed in a receiving space on the inner periphery of the electrochemical unit frame 1; the seal 3 is disposed between the electrochemical unit frame 1 and the membrane electrode 2. The membrane electrode 2 includes at least one stacked unit, with a gap between the at least one stacked unit and the electrochemical unit frame 1; the seal 3 includes a lip 32 extending along the thickness direction of the electrochemical unit 100 into the gap.

[0028] As shown in Figures 2 to 4, taking a proton exchange membrane battery as an example, the stacked unit of the membrane electrode 2 may include PTL 21 and PEM. There is a gap between PTL 21 and the electrochemical unit frame 1, and the lip 32 extends into the gap along the thickness direction of the electrochemical unit.

[0029] When placing the PTL 21, if the size of the PTL 21 is larger than the size of the containment space within the electrochemical unit frame 1, the porous transport layer 21 cannot be placed within that containment space. Therefore, the size of the PTL 21 needs to be slightly smaller than the size of the containment space, so that there is a gap between the PTL 21 and the electrochemical unit frame 1.

[0030] By providing a lip 32 to the seal 3, which extends along the thickness direction within the gap, the sealing contact area between the seal 3 and the PTL 21 is increased, thereby improving the sealing performance of the seal 3. Simultaneously, the seal 3 possesses a certain degree of elastic deformation capability. By pressing the PTL against the seal 3, particularly the lip 32, the PTL 21 can accommodate certain tolerances, and the PTL 21 can be more easily installed and secured.

[0031] According to some optional embodiments, a flow channel 11 is provided on one side of the electrochemical unit frame 1 in the thickness direction, and the extension of the lip 32 in the thickness direction does not enter the flow channel 11.

[0032] As shown in Figures 2 to 4, the lip 32 extends beyond the inner peripheral side of the electrochemical unit frame 1 in the thickness direction within the gap, that is, it will not extend into the flow channel 11, so as to avoid the lip 32 obstructing the flow within the flow channel.

[0033] According to some optional embodiments, as shown in Figures 2 to 4, the electrochemical unit frame 1 includes a support platform 12 extending toward the inner peripheral side, and the outer peripheral portion of the membrane electrode 2 is disposed on the support platform 12. The seal 3 includes a main body 31 disposed between the support platform 12 and the outer peripheral portion of the membrane electrode 2, and a lip 32 is formed by extending along the thickness direction from the inner peripheral edge of the main body 31.

[0034] By providing a support platform 12, a portion of the outer periphery of the membrane electrode 2 can be mounted on the support platform 12, making the membrane electrode 2 more stable after installation with the electrochemical unit frame 1. In the thickness direction, the main body 31 is disposed between the support platform 12 and the outer periphery of the membrane electrode 2, providing a seal between them; while the lip 32 provides a seal between the inner periphery of the electrochemical unit frame 1 and the outer periphery of the PTL 21. The extension direction of the lip 32 is perpendicular to the extension direction of the main body 31, making the cross-section of the sealing element 3 L-shaped, wrapping around a portion of the surface on one side of the thickness direction and a portion of the surface on the inner periphery of the electrochemical unit frame 1, resulting in a better sealing effect.

[0035] According to some alternative embodiments, the seal 3 is made of a hyperelastic material. For example, the seal 3 is made of a rubber material with elastic deformation and is formed on the support platform 12 by a vulcanization process.

[0036] According to some optional embodiments, as shown in Figures 2 to 5, the thickness of the main body 31 is varied. More specifically, the main body 31 has a wavy surface with varying heights on the side facing away from the support platform 12 in the thickness direction, that is, on the side facing the outer peripheral portion of the membrane electrode 2.

[0037] By designing the surface of the main body 31 as a wave shape, the sealing element 3, especially the main body 31, is made resistant to high pressure and achieves a self-sealing function. That is, the greater the pressure in the thickness direction, the more the wave-shaped surface is compressed and deformed, and the better the sealing effect of the main body 31 will be.

[0038] According to an embodiment of the present invention, an electrochemical device is also provided. Referring to FIG1, the electrochemical device includes an electrochemical unit group 1000 and two end plates 2000. The electrochemical unit group 1000 includes a plurality of electrochemical units 100 as described in any one of the above embodiments, stacked together. The two end plates 2000 are respectively disposed at both ends of the stacking direction of the electrochemical unit group 1000.

[0039] By providing a lip 32 to the seal 3, the seal 3 can serve both as a seal and as a compression connection for the PTL and the electrochemical unit frame 1. The seal 3 has good sealing performance, allowing for better stacking of the components of the membrane electrode 2, and the seal 3 is easy to manufacture and has low cost.

[0040] Furthermore, by setting the surface of the main body 31 on the side away from the support platform 12 in the thickness direction to a wave-like shape with varying heights, the high pressure resistance of the seal 3 can be improved, and the seal 3 can achieve self-sealing. That is, in the thickness direction, the greater the pressure on the seal 3, the better the sealing effect.

[0041] While possible embodiments have been described exemplarily in the foregoing description, it should be understood that numerous variations of embodiments exist through combinations of all known and readily conceived technical features and implementation methods. Furthermore, it should be understood that the exemplary embodiments are merely examples and do not in any way limit the scope, application, or construction of the invention. The foregoing description is more intended to provide those skilled in the art with technical guidance for transforming at least one exemplary embodiment, wherein various changes, particularly regarding the function and structure of the components, can be made without departing from the scope of the claims.

Claims

1. An electrochemical unit, characterized in that, include: Electrochemical unit framework (1); Membrane electrode (2), which is disposed in the accommodating space on the inner periphery of the electrochemical unit frame (1); as well as A sealing element (3) is disposed between the electrochemical unit frame (1) and the membrane electrode (2); The membrane electrode (2) includes at least one stacked unit, which has a gap with the electrochemical unit frame (1). The seal (3) includes a lip (32) which extends into the gap along the thickness direction of the electrochemical unit.

2. The electrochemical unit according to claim 1, characterized in that, A flow channel (11) is provided on one side of the electrochemical unit frame (1) in the thickness direction, and the lip (32) does not extend into the flow channel (11) in the thickness direction.

3. The electrochemical unit according to claim 1, characterized in that, The electrochemical unit frame (1) includes a support platform (12) extending toward the inner peripheral side, and the membrane electrode (2) has an outer peripheral side portion disposed on the support platform (12); The sealing element (3) includes a main body (31) disposed between the support platform (12) and the outer peripheral portion of the membrane electrode (2), and the lip (32) is formed by extending the inner peripheral edge of the main body (31) along the thickness direction.

4. The electrochemical unit according to claim 3, characterized in that, The seal (3) is formed on the support platform (12) by a vulcanization process.

5. The electrochemical unit according to claim 3, characterized in that, The thickness of the main body (31) is variable.

6. The electrochemical unit according to claim 5, characterized in that, The main body (31) has a wavy surface with varying heights on the side away from the support platform (12) in the thickness direction.

7. The electrochemical unit according to claim 1, characterized in that, The seal (3) is made of a superelastic material.

8. The electrochemical unit according to claim 7, characterized in that, The seal (3) is made of rubber material.

9. The electrochemical unit according to claim 1, characterized in that, The at least one stacked unit includes a porous transport layer (21) and a proton exchange layer, the porous transport layer (21) having a gap with the electrochemical unit frame (1), and the lip (32) extending into the gap along the thickness direction of the electrochemical unit.

10. An electrochemical device, characterized in that, include: An electrochemical unit group (1000) comprising a plurality of electrochemical units (100) stacked as described in any one of claims 1 to 9; and Two end plates (2000) are respectively disposed at both ends of the stacking direction of the electrochemical unit group (1000).

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