Electrochemical cell and electrochemical stack

Abstract

The utility model relates to an electrochemical cell and an electrochemical stack. The electrochemical unit comprises a battery frame, wherein an active area is arranged in the middle of the battery frame; the bipolar plates are respectively stacked on two side surfaces of the battery frame, each bipolar plate is divided into a conductive region and an insulating region, the conductive region is coated with a conductive coating, and in the stacking direction of the battery frame and the bipolar plates, the projection region of the conductive coating on the battery frame covers the conductive coating to cover the active region; an insulating region surrounds the conductive region and is coated with an insulating coating. The wire area of the bipolar plate does not affect the work of the water electrolysis unit, and the insulating area is arranged outside the conductive area of the bipolar plate. According to the bipolar plate, the insulation function originally borne by the battery frame is transferred to the bipolar plate, the insulation function can be achieved, the area of a conductive area on the bipolar plate is reduced, the area of a conductive coating for coating the conductive area is further reduced, and therefore the cost of the conductive coating is reduced. In addition, coating of the insulation area on the bipolar plate is easier, and the production difficulty is reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of hydrogen production by electrolyzing water, in particular to an electrochemical unit and an electrochemical stack applied to a water electrolysis unit or a fuel cell unit. Background Art

[0002] A water electrolysis stack (also known as a water electrolysis cell stack) is used to electrolyze water to produce hydrogen and oxygen, and is used in the field of hydrogen for water electrolysis stacks or all-battery new energy. The water electrolysis stack in the related technology includes a first end plate, a water electrolysis cell, and a second end plate. Each water electrolysis cell includes a cell frame, a bipolar plate (abbreviation: BPP), a sealing gasket, an O-ring, a proton exchange membrane coated with a catalyst (also known as a catalyst coated membrane, abbreviation: CCM), a titanium mesh, a titanium felt, a carbon paper, and a steel mesh.

[0003] A reaction through-hole is usually provided in the middle of the cell frame in the water electrolysis unit. The proton exchange membrane coated with a catalyst (also known as a catalyst coated membrane, abbreviation: CCM), the titanium mesh, the titanium felt, the carbon paper, the steel mesh, etc. are located in the reaction through-hole, and the area corresponding to the reaction through-hole is called the active area. Insulation is very important for the entire water electrolysis unit. In order to transfer or concentrate electrical energy to the active area at the reaction through-hole as much as possible, the resistance of the cell frame should be as large as possible at the active area, and an insulating area is usually provided around the reaction through-hole of the cell frame to avoid energy loss.

[0004] In the related technology, an insulating method for insulating the cell frame is that the cell frame is made of a polymer material, but the polymer material is expensive and has a high cost; another insulating method is that the cell frame uses a metal material, but an insulating plastic coating is applied. However, the cell frame has a non-planar structure, and the process of coating the insulating coating in the insulating area is relatively complex, with a high process difficulty and cost. Summary of the Utility Model

[0005] To overcome the problems existing in the related technology, the present disclosure provides an electrochemical unit and an electrochemical stack.

[0006] According to the first aspect of the embodiments of the present disclosure, the present disclosure provides an electrochemical unit, including: a cell frame, with an active area provided in the middle of the cell frame; bipolar plates respectively stacked on both side surfaces of the cell frame, wherein the bipolar plates are divided into a conductive area and an insulating area, the conductive area is coated with a conductive coating, and in the direction of stacking of the cell frame and the bipolar plates, the projection area of the conductive coating on the cell frame covers the active area; the insulating area surrounds the conductive area and is coated with an insulating coating.

[0007] In some embodiments, the cell frame is made of an insulating material or a conductive material.

[0008] In some embodiments, the conductive coating is made of a platinum material.

[0009] In some embodiments, the insulating coating is a parylene coating.

[0010] In some embodiments, the bipolar plate has a plate-like structure, and the surface of the bipolar plate that fits with the battery frame is a flat plane.

[0011] In some embodiments, the bipolar plate further includes an isolation region that surrounds the outside of the conductive region and is located between the conductive region and the insulating region, and the isolation region is used to isolate the conductive coating from the insulating coating.

[0012] In some embodiments, the battery frame includes a cathode surface and an anode surface, and the battery frame is provided with sealing grooves on the cathode surface and the anode surface respectively, and the sealing grooves surround the active region. Wherein, the electrochemical cell further includes a sealing gasket installed in the sealing groove.

[0013] In some embodiments, a middle hole, a support portion surrounding the middle hole, and an enclosing portion surrounding the support portion are provided in the middle of the battery frame, and the support surface of the support portion is close to the cathode surface; the electrochemical cell further includes: a titanium mesh, a titanium felt, a proton exchange membrane coated with a catalyst, a carbon paper, and a steel mesh; wherein, the titanium mesh and the titanium felt are located in the middle hole, and the proton exchange membrane coated with a catalyst, the carbon paper, and the steel mesh are located in the enclosing portion and are sequentially supported on the support surface of the support portion.

[0014] In some embodiments, the electrochemical cell is a proton exchange membrane water electrolysis cell or a proton exchange membrane fuel cell unit.

[0015] According to a second aspect of the embodiments of the present disclosure, the present disclosure provides an electrochemical stack, including: a first end plate; a second end plate; and an electrochemical cell sandwiched between the first end plate and the second end plate, wherein the electrochemical cell is formed by stacking a plurality of electrochemical cells as described in the first aspect.

[0016] The technical solutions provided by the embodiments of the present disclosure may include the following beneficial effects:

[0017] The insulating function originally borne by the battery frame is transferred to the bipolar plate, realizing the transfer of the insulating function. Since the bipolar plate increases the insulating region, the area of the conductive region on the bipolar plate is reduced, and thus the total area of the conductive coating applied is reduced. This not only reduces the usage amount of the conductive coating but also directly cuts the manufacturing cost. At the same time, compared with applying an insulating coating on the battery frame, the process of applying an insulating coating on the bipolar plate is simpler, reducing the production difficulty and improving the production efficiency. Description of the Drawings

[0018] The accompanying drawings here are incorporated into and form a part of this specification, showing embodiments consistent with the present disclosure, and are used together with the specification to explain the principles of the present disclosure.

[0019] Figure 1 is a perspective view of an electrochemical stack shown according to an exemplary embodiment;

[0020] Figure 2 is a cross-sectional view of an electrochemical cell shown according to an exemplary embodiment;

[0021] Figure 3 is a plan view of a bipolar plate shown according to an exemplary embodiment. Detailed Description of the Embodiments

[0022] Here, the exemplary embodiments will be described in detail, and the examples are shown in the accompanying drawings. When the following description refers to the accompanying drawings, unless otherwise indicated, the same numerals in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present disclosure. On the contrary, they are merely examples of devices and methods consistent with some aspects of the present disclosure as detailed in the appended claims.

[0023] To solve the above technical problems, as Figure 1 and Figure 2 shown, the present disclosure provides an electrochemical cell 100, and a plurality of electrochemical cells 100 connected in series can form an electrochemical stack.

[0024] Among them, the electrochemical cell 100 can be a proton exchange membrane water electrolysis cell (Proton Exchange Membrane Water Electrolysis, abbreviated as PEMWE). A plurality of PEMWEs stacked in series can form a water electrolysis cell, and the water electrolysis cell is clamped between a first end plate 200 and a second end plate 300 to jointly form a water electrolysis stack. The PEMWE can convert intermittent electric energy, such as the electric energy generated by wind energy, water energy, and solar energy, into hydrogen energy, and realize storage, transportation, and application.

[0025] The electrochemical cell 100 can also be a proton exchange membrane fuel cell unit (Proton Exchange Membrane Fuel Cell, abbreviated as PEMFC). A plurality of PEMFCs stacked in series form a fuel cell stack, and the fuel cell stack is clamped between a first end plate 200 and a second end plate 300 to jointly form a fuel cell stack. The PEMFC converts chemical energy into electric energy through an electrochemical reaction, and at the same time generates a small amount of heat energy to realize its functions of electric energy conversion and supply.

[0026] This disclosure takes a water electrolysis unit as an example. Each water electrolysis unit includes a cell frame 10, a bipolar plate 20 (abbreviated as BPP), a sealing gasket 30, an O-ring 90, a proton exchange membrane coated with catalyst 60 (also known as a catalyst coated membrane, abbreviated as CCM), a titanium mesh 40, a titanium felt 50, a carbon paper 70, and a steel mesh 80.

[0027] Among them, a middle hole 15, a support portion 152, and an enclosing portion 151 are provided in the middle of the cell frame 10. The middle hole 15 penetrates the cell frame 10. The support portion 152 surrounds the outer periphery of the middle hole 15 and is lower than the cathode surface 11 of the cell frame 10. The enclosing portion 151 surrounds the outer periphery of the support portion 152. Among them, the proton exchange membrane coated with catalyst 60 (CCM) is enclosed within the enclosing portion 151 and supported on the support surface of the support portion 152. Hydrogen is generated on the side of the CCM facing the enclosing portion 151, and oxygen is generated on the side of the CCM facing the support portion 152.

[0028] The cell frame 10 includes two side surfaces. The side corresponding to the side where the CCM generates hydrogen is the cathode surface 11 of the cell frame 10 (i.e., the side close to the enclosing portion 151), and the side corresponding to the side where the CCM generates oxygen is the anode surface 12 of the cell frame 10 (i.e., the side close to the support portion 152).

[0029] The carbon paper 70 and the steel mesh 80 are provided on the cathode side of the CCM and installed within the enclosing portion 151. The carbon paper 70 is arranged between the CCM and the steel mesh 80. Among them, the carbon paper 70 is the gas diffusion layer, abbreviated as GDL. The function of the GDL is to diffuse the water and hydrogen generated on the cathode side of the CCM into the pipeline. In addition, an O-ring groove is provided on the outer periphery of the support portion 152. The O-ring groove is located within the enclosing portion 151, and the O-ring 90 is installed in the O-ring groove. The O-ring 90 abuts against one side of the anode side of the CCM, thereby playing a role in support and sealing.

[0030] The titanium mesh 40 and the titanium felt 50 are located on the anode side of the CCM and installed within the middle hole 15. At the same time, the titanium felt 50 is arranged between the anode side of the CCM and the titanium mesh 40.

[0031] Furthermore, the CCM is located in the area corresponding to the middle hole 15 of the cell frame 10, that is, the active area 13 of the cell frame 10. Energy (such as intermittent electric energy) is concentrated to supply power to the active area 13, so that oxygen and hydrogen are generated in the active area 13. The cell frame 10 is respectively provided with sealing grooves 14 on the cathode surface 11 and the anode surface 12. The sealing grooves 14 surround the active area 13. Among them, the sealing gasket 30 is installed in the sealing grooves 14 to prevent the leakage and mixing of hydrogen and oxygen, and make the generated hydrogen and oxygen be transported into the corresponding manifold holes (not shown in the figure) as much as possible.

[0032] The bipolar plate 20 includes two plates, namely an anode plate and a cathode plate, and both the anode plate and the cathode plate are in a plate-like structure. The anode plate and the cathode plate are respectively disposed on the anode surface 12 and the cathode surface 11 of the battery frame 10.

[0033] Both the anode plate and the cathode plate are divided into a conductive region 21 and an insulating region 22. In the direction in which the battery frame 10 and the anode plate and the cathode plate are stacked, the projection region of the conductive region 21 on the battery frame 10 covers the active region 13 of the battery frame 10. The conductive region 21 is coated with a conductive coating, so that it can conduct electricity to provide electrical energy to the active region 13 and ensure the normal operation of the electrochemical unit 100. The insulating region 22 surrounds the periphery of the conductive region 21 and is coated with an insulating coating, avoiding unnecessary energy loss caused by the dispersion of electrical energy. It can be seen that the electrochemical unit 100 of the present disclosure transfers the insulation function originally borne by the battery frame 10 to the bipolar plate 20, realizing the transfer of the insulation function.

[0034] Among them, the conductive coating is made of platinum material. Platinum material is an expensive metal. In the related art, the entire surface of the bipolar plate 20 needs to be coated with a platinum coating, resulting in increased costs. In this embodiment, the bipolar plate 20 is divided into an insulating region 22 and a conductive region 21. Since the bipolar plate 20 increases the insulating region 22, the area of the conductive region 21 on the bipolar plate 20 is reduced, and thus the total area of the conductive coating (i.e., platinum metal) to be coated is reduced. This not only reduces the usage amount of the conductive coating but also directly cuts down the manufacturing cost.

[0035] In some embodiments, the insulating coating is a parylene coating. The use of the parylene coating not only improves the insulation effect but also reduces the material usage due to its good adhesion and thin-film characteristics, further reducing the cost and showing great potential for wide application in the field of battery manufacturing.

[0036] In this embodiment, the battery frame 10 is made of an insulating material or a conductive material. The selection types of the battery frame 10 are no longer limited to a single material, and the material selection of the battery frame 10 becomes more flexible. It can either use a more cost-effective insulating material, or a metal conductive material, or a plastic coating can be applied on the metal to achieve insulation. The insulating region 22 on the bipolar plate 20 ensures that even if the battery frame 10 uses a conductive material, the electrochemical unit 100 is still safe and reliable. This not only reduces the dependence on expensive insulating materials, simplifies the process requirements for plastic coatings, but also significantly reduces the cost and improves the overall economic efficiency.

[0037] In some embodiments, the bipolar plate 20 has a plate-like structure, and the surface of the bipolar plate 20 that fits with the battery frame 10 is a flat plane. It can be seen from this that compared with applying an insulating coating on the not-flat-enough battery frame 10, the flat bipolar plate 20 not only reduces the difficulty of applying the insulating coating, ensures the uniformity and integrity of the insulating coating, but also effectively improves the production efficiency, reduces the additional costs and time consumption brought by complex surface treatment, and creates favorable conditions for large-scale production.

[0038] As Figure 3 shown, the bipolar plate 20 further includes an isolation region 23. The isolation region 23 surrounds the outside of the conductive region 21 and is located between the conductive region 21 and the insulating region 22. The isolation region 23 is used to isolate the conductive coating from the insulating coating. No coating is applied to the isolation region 23. Further, a tape can be attached to the isolation region 23. The tape can be attached to the bipolar plate 20 in advance and then the conductive coating or the insulating coating is applied. On the one hand, it defines the scope of the conductive coating and the insulating coating, greatly simplifies the coating process when applying the conductive coating and the insulating coating, and makes the production process more efficient; on the other hand, it fundamentally eliminates the interference between the conductive coating and the insulating coating when applying them, and ensures a good transition between the two coatings.

[0039] Based on the same inventive concept, the present disclosure provides an electrochemical stack. The specific ways to achieve the functions in the electrochemical stack in the above embodiments have been described in detail in the embodiments related to the electrochemical cell 100, and will not be elaborated here.

[0040] It can be understood that "a plurality of" in the present disclosure means two or more, and other quantifiers are similar. "And / or" describes the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can mean: A exists alone, A and B exist simultaneously, and B exists alone. The character " / " generally means that the associated objects before and after are in an "or" relationship. The singular forms of "a", "the" and "said" are also intended to include the plural forms unless the context clearly indicates otherwise.

[0041] It can be further understood that terms such as "first", "second", etc. are used to describe various structures, but these structures should not be limited to these terms. These terms are only used to distinguish the same type of structures from each other, and do not represent a specific order or importance. In fact, the expressions such as "first", "second", etc. can be used interchangeably. For example, without departing from the scope of the present disclosure, the first structure can also be called the second structure, and similarly, the second structure can also be called the first structure.

[0042] It can be further understood that the orientation or positional relationship indicated by terms such as "upper" and "lower" is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present embodiment and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation.

[0043] Those skilled in the art will readily conceive of other embodiments of the present disclosure after considering the specification and practicing the utility model disclosed herein. This application is intended to cover any variations, uses, or adaptations of the present disclosure, which follow the general principles of the present disclosure and include known common general knowledge or conventional technical means in the technical field not disclosed by the present disclosure. The specification and embodiments are only regarded as exemplary, and the true scope and spirit of the present disclosure are pointed out by the following claims.

[0044] It should be understood that the present disclosure is not limited to the exact structures already described and shown in the drawings, and various modifications and changes can be made without departing from its scope. The scope of the present disclosure is only limited by the appended claims.

Claims

1. An electrochemical unit (100), characterized in that, Comprising: A battery frame (10), with an active area (13) provided in the middle of the battery frame (10); Bipolar plates (20), respectively stacked on both side surfaces of the battery frame (10), wherein, the bipolar plates (20) are divided into a conductive area (21) and an insulating area (22), the conductive area (21) is coated with a conductive coating, in the stacking direction of the battery frame (10) and the bipolar plates (20), the projection area of the conductive coating on the battery frame (10) covers the active area (13); the insulating area (22) surrounds the conductive area (21) and is coated with an insulating coating.

2. The electrochemical cell (100) according to claim 1, wherein, The battery frame (10) is made of an insulating material or a conductive material.

3. The electrochemical cell (100) according to claim 1, wherein, The conductive coating is made of a platinum material.

4. The electrochemical cell (100) according to claim 1, wherein, The insulating coating is a parylene coating.

5. The electrochemical cell (100) according to claim 1, wherein, The bipolar plate (20) has a plate-like structure, and the surface of the bipolar plate (20) that fits with the battery frame (10) is a flat plane.

6. The electrochemical cell (100) according to claim 1, wherein, The bipolar plate (20) further includes an isolation area (23), the isolation area (23) surrounds the outside of the conductive area (21) and is located between the conductive area (21) and the insulating area (22), and the isolation area (23) is used to isolate the conductive coating from the insulating coating.

7. The electrochemical cell (100) according to claim 1, wherein, The battery frame (10) includes a cathode surface (11) and an anode surface (12), and the battery frame (10) is respectively provided with sealing grooves (14) on the cathode surface (11) and the anode surface (12), the sealing grooves (14) surround the active area (13), wherein, the electrochemical cell (100) further includes a sealing gasket (30), and the sealing gasket (30) is installed in the sealing grooves (14).

8. The electrochemical cell (100) according to claim 7, wherein, The middle of the battery frame (10) is provided with a middle hole, a support part (152) surrounding the middle hole (15), and an enclosing part (151) surrounding the support part (152), and the support surface of the support part (152) is close to the cathode surface (11); The electrochemical cell (100) further includes: a titanium mesh (40), a titanium felt (50), a proton exchange membrane coated with a catalyst (60), a carbon paper (70), and a steel mesh (80); Wherein, the titanium mesh (40) and the titanium felt (50) are located in the middle hole (15), and the proton exchange membrane coated with catalyst (60), the carbon paper (70) and the steel mesh (80) are located in the surrounding portion (151) and are successively supported on the supporting surface of the supporting portion (152).

9. The electrochemical cell (100) according to claim 1, wherein the electrochemical cell (100) is a proton exchange membrane water electrolysis cell or a proton exchange membrane fuel cell unit.

10. An electrochemical stack, characterized in that, Comprising: a first end plate (200); a second end plate (300); and an electrochemical cell, the electrochemical cell being clamped between the first end plate (200) and the second end plate (300), wherein the electrochemical cell is formed by stacking a plurality of electrochemical cells (100) as described in any one of claims 1 to 9.

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