Electrode support structure and electrolyzer for hydrogen production by water electrolysis

Abstract

This invention provides an electrode support structure and an electrolyzer for hydrogen production via water electrolysis. The electrode support structure includes a support plate body, a first support portion, and a second support portion. The support plate body has a first surface and a second surface arranged opposite to each other along its thickness direction; and a plurality of through-holes and arrayed first and second forming holes. The first support portion includes a plurality of first support units located on the first surface, the plurality of first support units being located above the plurality of first forming holes and corresponding to each other; the upper surface of the first support unit has a mounting plane. The second support portion includes a plurality of second support units located on the second surface, the plurality of second support units being located below the plurality of second forming holes and corresponding to each other; the second support units are arched structures. This invention features a simple design, convenient installation, reduced production costs, controllable finished product quality, and is suitable for large-scale manufacturing.

Description

Technical Field

[0001] This utility model relates to the field of water electrolysis for hydrogen production technology, and in particular to an electrode support structure and an electrolyzer for water electrolysis for hydrogen production. Background Technology

[0002] Hydrogen production through water electrolysis is a process that generates hydrogen and oxygen by electrolyzing water, and it is widely used in energy storage, fuel cells, and other fields. With the continuous expansion of renewable energy hydrogen production, electrolyzers are developing towards larger sizes and higher current densities. Under this trend, the performance of the electrode support structure has an increasingly significant impact on the uniformity of current distribution, bubble removal efficiency, and mechanical stability. Depending on the electrolysis technology, the support structure needs to adapt to alkaline environments (such as alkaline electrolyzers) or strongly acidic environments (such as proton exchange membrane electrolyzers) and meet differentiated mechanical and electrical conductivity requirements.

[0003] In water electrolysis for hydrogen production, traditional electrode support structures are mainly divided into stretched mesh and elastic mesh, but these structures have many problems in practical applications. Stretched mesh is prone to mechanical damage to the diaphragm in the electrolyzer, affecting the cell's sealing and safety. This damage not only reduces the electrolyzer's service life but may also lead to electrolyte leakage, affecting electrolyte distribution and hydrogen evolution efficiency, thus reducing overall hydrogen production. Elastic mesh, under long-term exposure to electrolyte, air bubble erosion, or mechanical stress, will experience rebound attenuation and failure. This results in uneven electrode spacing, affecting current distribution and electrolysis efficiency. Uneven current distribution reduces the efficiency of the electrolysis reaction, increases energy consumption, and reduces hydrogen production efficiency. Therefore, this invention provides an electrode support structure and electrolyzer for water electrolysis for hydrogen production. Utility Model Content

[0004] The main purpose of this invention is to provide an electrode support structure and an electrolyzer for hydrogen production by water electrolysis, which solves the technical problems of uneven current distribution and low hydrogen production efficiency.

[0005] To achieve the above objectives, this utility model provides an electrode support structure for hydrogen production by water electrolysis, the electrode support structure comprising: a support plate body, a first support portion, and a second support portion.

[0006] The support plate body has a first surface and a second surface that are arranged opposite to each other along its own thickness direction; and a plurality of through-holes and arrayed first and second forming holes.

[0007] The first support portion includes a plurality of first support units located on the first surface. The plurality of first support units are located above the plurality of first forming holes and are arranged in a one-to-one correspondence. The upper surface of the first support unit has a mounting plane.

[0008] The second support portion includes a plurality of second support units located on the second surface. The plurality of second support units are located below the plurality of second forming holes and are arranged in a one-to-one correspondence. The second support unit is an arched structure.

[0009] In some embodiments, the first support unit and the second support unit are arranged in a multi-row array.

[0010] In some rows, there are N first support units between any two adjacent second support units.

[0011] Where N is an integer, ranging from 4 to 6.

[0012] In some embodiments, the second support units in different rows are arranged in an alternating or parallel manner.

[0013] In some embodiments, the cross-sectional shape of the first support unit along the height direction is trapezoidal or rectangular.

[0014] The second support unit is V-shaped or U-shaped, and the connection between the second support unit and the first surface is an arc-shaped transition.

[0015] In some embodiments, the height of the first support unit is 0.8 to 1.0 mm, the length is 4 to 6 mm, and the width is 1 to 2 mm; the spacing between the arrays of the first support units is 1.5 to 3.5 mm.

[0016] In some embodiments, the arched structure of the second support unit includes an arch height of 2.4 to 2.6 mm and an arch width of 2.5 to 8 mm.

[0017] In some embodiments, the spacing between the support points of the second support unit is greater than the length of the first support unit.

[0018] The first support unit and the second support unit are arranged in an array along the same direction.

[0019] In some embodiments, the electrode support structure is a one-piece molded structure.

[0020] The dimensional tolerance of the electrode support structure is ±0.05mm.

[0021] In some embodiments, the thickness of the support plate body is 0.2 to 0.5 mm.

[0022] This utility model also provides an electrolyzer for producing hydrogen by electrolysis of water, including electrodes, a diaphragm, an electrode plate, and the aforementioned electrode support structure for producing hydrogen by electrolysis of water. The electrodes, the electrode support structure for producing hydrogen by electrolysis of water, and the electrode plate are sequentially arranged on both sides of the diaphragm, and the electrodes are attached to the sides of the diaphragm.

[0023] Compared with the prior art, the beneficial effects of this utility model are:

[0024] The above-described utility model provides an electrode support structure and an electrolyzer for hydrogen production via water electrolysis. The electrode support structure includes a support plate body, a first support portion, and a second support portion. The support plate body has a first surface and a second surface, providing a double-layer structure that can withstand greater pressure and has better resistance to deformation. The first support portion includes multiple first support units located on the first surface. The upper surface of each first support unit has a mounting plane, which increases the effective contact area and contact stability between the electrode and the electrode support structure, reduces contact resistance, and improves current conduction efficiency, thereby increasing electrolysis efficiency. The second support portion includes multiple arrayed second support units. Each second support unit has an arched structure with a rebound effect. Elastic deformation ensures a tight fit between the electrode and the diaphragm and absorbs thermal expansion stress during temperature fluctuations, allowing it to better disperse the point of force application when subjected to external forces, avoiding structural damage caused by localized stress concentration. This utility model's electrode support structure significantly improves the contact stability between the electrode and the support structure, enhances structural strength and durability, optimizes the flow field distribution inside the electrolyzer, and thus improves the overall performance of the electrolyzer. Meanwhile, its ease of installation reduces production costs, making it highly practical and economical, and solving technical problems such as uneven current distribution and low hydrogen production efficiency. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0026] Figure 1 This is a schematic diagram of the first surface in the electrode support structure for hydrogen production by water electrolysis of this utility model;

[0027] Figure 2 This is a schematic diagram of the second surface in the electrode support structure for hydrogen production by water electrolysis of this invention.

[0028] The reference numerals in the attached figures are as follows: 10, electrode support structure; 11, support plate body; 12, first support part; 13, second support part; 21, first surface; 22, second surface; 31, first forming hole; 32, second forming hole; 33, first support unit; 34, second support unit.

[0029] The implementation, functional features, and advantages of this utility model will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0030] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0031] Furthermore, in this utility model, descriptions involving "first," "second," etc., are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features.

[0032] Furthermore, the technical solutions of the various embodiments of this utility model can be combined with each other, but only if they are based on the ability of a person skilled in the art to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by this utility model.

[0033] The embodiments of this utility model provide an electrode support structure and an electrolyzer for hydrogen production by water electrolysis, which solves the technical problems of uneven current distribution and low hydrogen production efficiency.

[0034] A water beam structure for hot rolling furnace solves the technical problem of excessive temperature difference in different parts of slab causing black marks on the water beam that affect product quality.

[0035] in, Figure 1 This is a schematic diagram of the first surface in the electrode support structure for hydrogen production by water electrolysis of this utility model; Figure 2 This is a schematic diagram of the second surface in the electrode support structure for hydrogen production by water electrolysis of this invention.

[0036] To understand the electrode support structure for hydrogen production via water electrolysis, see [link to relevant documentation]. Figure 1 and Figure 2This utility model provides an electrode support structure for hydrogen production by water electrolysis. The electrode support structure 10 includes: a support plate body 11, a first support part 12, and a second support part 13.

[0037] The support plate body 11 has a first surface 21 and a second surface 22 that are disposed opposite to each other along its own thickness direction; and a plurality of through holes 31 and second forming holes 32 arranged in an array.

[0038] See Figure 1 and Figure 2 In some embodiments, the support plate body has a first surface and a second surface symmetrical along the thickness direction. The first surface has a plurality of first forming holes, and the second surface has a plurality of second forming holes. This is used to optimize electrolyte flow and uniform electrode force, and to reduce resistance.

[0039] The first support portion 12 includes a plurality of first support units 33 located on the first surface 21. The plurality of first support units 33 are located above the plurality of first forming holes 31 and are arranged in a one-to-one correspondence. The upper surface of the first support unit 33 has a mounting plane.

[0040] For a better understanding of the structure of the first support section, please refer to [link / reference]. Figure 1 In some embodiments, each first support unit corresponds to a first forming hole and is located directly above the first forming hole, forming a one-to-one array arrangement. The upper surfaces of the plurality of first support units have mounting planes for directly contacting the electrode sheets, providing a stress-free contact interface. This ensures uniform force distribution, stable contact, and avoids localized overload. The planes can form a large-area uniform contact with the electrode sheets or diaphragms, avoiding excessively high or low local pressure, reducing contact resistance, and improving current conduction efficiency. It can also withstand higher current densities, extending the service life of the electrode sheets and diaphragms.

[0041] The second support portion 13 includes a plurality of second support units 34 located on the second surface 22. The plurality of second support units 34 are located below the plurality of second forming holes 32 and are arranged in a one-to-one correspondence. The second support unit 34 has an arched structure.

[0042] To understand the structure of the second support section, see [link / reference]. Figure 2 In some embodiments, each second support unit is located directly below a second forming hole, and the projection of its outer contour in the thickness direction completely covers the second forming hole, forming a one-to-one array. See also Figure 2 The arched top faces the second forming hole, and the arched base connects to the second surface to form a semi-enclosed cavity, which serves as both an electrolyte buffer chamber and an elastic support. The electrolyte flows through the semi-enclosed cavity, reducing turbulence and ensuring smoother flow. It also prevents gas stagnation, allowing bubbles to escape quickly and reducing concentration polarization. Simultaneously, it reduces pressure drop, decreases energy consumption, and improves electrolysis efficiency.

[0043] See Figure 2 In some embodiments, the second support unit is an arched structure. The arched structure is resilient; it undergoes elastic deformation under pressure, absorbing energy through changes in the curvature of the arch's apex and returning to its original shape after pressure release, providing continuous resilience. This deformation ensures a tight fit between the electrode plates and the diaphragm and absorbs thermal expansion stress during temperature fluctuations. The arched structure distributes localized concentrated loads along the arched curve to the support points on both sides. During frequent start-ups and shutdowns of the electrolytic cell or power fluctuations, the elastic deformation capability of the arched structure can alleviate repetitive stress.

[0044] The aforementioned utility model provides an electrode support structure for hydrogen production via water electrolysis, comprising a support plate body, a first support portion, and a second support portion. The support plate body has a first surface and a second surface, providing a double-layer structure capable of withstanding greater pressure and exhibiting greater resistance to deformation. The first support portion includes multiple first support units located on the first surface. The upper surface of each first support unit has a mounting plane, which increases the effective contact area and contact stability between the electrode and the electrode support structure, reduces contact resistance, and improves current conduction efficiency, thereby enhancing electrolysis efficiency. The second support portion includes multiple second support units arranged in an array. Each second support unit has an arched structure with a rebound effect. Elastic deformation ensures a tight fit between the electrode and the diaphragm and absorbs thermal expansion stress during temperature fluctuations, allowing it to better disperse the point of force application when subjected to external forces, avoiding structural damage caused by localized stress concentration.

[0045] See Figure 1 and Figure 2 In some embodiments, the first support unit 33 and the second support unit 34 are arranged in a multi-row array.

[0046] In some rows, there are N first support units 33 between any two adjacent second support units 34.

[0047] Where N is an integer, ranging from 4 to 6.

[0048] To accommodate electrolytic cells of different shapes, the shape of the electrode support structure is adapted to the shape of the electrolytic cell. In some embodiments, the electrode support structure is circular, and the first support unit and the second support unit are arranged in a multi-row array. In some rows, there are five first support units between any two adjacent second support units.

[0049] Depending on the shape of the electrode support structure, the second support units 34 in different rows are arranged in an alternating or parallel manner. See also Figure 2 In some embodiments, the electrode support structure is circular, and the lengths of different rows are different, so the second support units are arranged in an alternating pattern in different rows.

[0050] To ensure that the electrode support structure has one layer for contact conductivity and another layer for resilience, in some embodiments, the first support unit 33 has a trapezoidal or rectangular cross-sectional shape along its height direction;

[0051] The second support unit 34 is V-shaped or U-shaped, and the connection between the second support unit 34 and the first surface 21 is an arc-shaped transition.

[0052] As a conductive contact layer, trapezoidal or rectangular shapes in some embodiments help form stable surface-to-surface contact with the electrodes, preventing conductive failure caused by fretting. By providing a larger planar contact area, contact resistance is reduced. Simultaneously, trapezoidal or rectangular shapes make it easier to ensure dimensional accuracy and surface flatness, reducing subsequent processing steps.

[0053] As an elastic rebound layer, in some embodiments, the V-shape exhibits symmetrical elastic deformation of the inclined surface under pressure, and the deformation recovers after unloading, providing rebound force. The inverted trapezoidal cross-section, wider at the top and narrower at the bottom, can create a "funnel effect," enhancing stress concentration during deformation and improving the rebound response speed. Moreover, the rounded transition between the first forming hole and the first surface avoids stress concentration at the interface between the conductive layer and the rebound layer, preventing cracks caused by repeated pressing. The rounded transition can also reduce microscopic unevenness at the contact interface, lowering contact resistance fluctuations.

[0054] In some embodiments, the height of the first support unit 33 is 0.8 to 1.0 mm, the length is 4 to 6 mm, and the width is 1 to 2 mm; the spacing between the arrays of the first support units 33 is 1.5 to 3.5 mm.

[0055] In some embodiments, the height of the first support unit is 0.8 mm, the length is 5 mm, and the width is 1 mm; the spacing between the arrays of the first support units is 2.5 mm.

[0056] In some embodiments, the arched structure of the second support unit 34 includes an arch height of 2.4 to 2.6 mm and an arch width of 2.5 to 8 mm.

[0057] In some embodiments, the arched structure of the second support unit includes an arch height of 2.5 mm and an arch width of 8 mm.

[0058] To ensure that the electrode support structure has one layer for contact conductivity and another for resilience, the first support unit and the second support unit must be used in combination. (See also...) Figure 2 In some embodiments, the spacing between the support points of the second support unit 34 is greater than the length of the first support unit 33.

[0059] The first support unit 33 and the second support unit 34 are arranged in an array along the same direction.

[0060] The arched structure spans at least one complete first support unit, preventing the formation of a suspended support. In some embodiments, the support point spacing of the second support unit is 8 mm, and the length of the first support unit is 5 mm.

[0061] Traditional electrolyzers use stretched mesh and elastic mesh as support structures. Elastic mesh requires processes such as weaving, corrugating, cutting, and edge rolling, while stretched mesh requires punching, cutting, and edge rolling. Both weaving and punching require individual weaving or punching, consuming significant time and reducing production capacity. Edge rolling is complex and leads to large dimensional deviations. Improper edge treatment during punching or cutting results in burrs or sharp edges; inaccurate weaving or stretching processes lead to uneven mesh size. Furthermore, the stretched mesh in traditional support structures, due to its slit-stretching forming, is uneven on both sides, and the slits can easily cause mechanical damage to the diaphragm in the electrolyzer, affecting its sealing and safety. The traditional stretched mesh structure and the low porosity of the elastic mesh result in high electrolyte flow resistance, affecting electrolyte distribution and hydrogen evolution efficiency, thus reducing overall hydrogen production. The elastic mesh relies on the limited resilience of the zapposphere. Under long-term exposure to electrolyte, bubble erosion, or mechanical stress, it experiences resilience decay and resilience failure, resulting in uneven electrode spacing, which affects current distribution and electrolysis efficiency.

[0062] Because the manufacturing process of traditional electrode support structures is complex, it not only consumes a lot of time and reduces production capacity, but may also lead to process defects such as large dimensional deviations, improper edge treatment resulting in burrs or sharp edges, and uneven mesh. Therefore, in some embodiments, the electrode support structure 10 is a one-piece molded structure.

[0063] The dimensional tolerance of the electrode support structure 10 is ±0.05mm.

[0064] In some embodiments, the electrode support structure 10 is formed by mold pressing, and the object of the mold pressing includes the first surface 21 and the second surface 22 of the support plate body 11.

[0065] To meet the requirements of use in different corrosive environments, in some embodiments, the electrode support structure can be made of titanium, nickel, stainless steel, or coated metal plates. It is used in various electrolytic hydrogen production systems such as alkaline water electrolysis (ALK) and proton exchange membrane water electrolysis (PEM).

[0066] To ensure controllable quality of the electrode support structure, in some embodiments, it is formed in a single press using a precision mold. The mold is integrally pressed, with the male mold forming the first support unit and the female mold forming the second support unit, with a dimensional tolerance of ±0.05mm. This method can improve the mechanical strength, gas venting efficiency, and stability of the electrode support structure during electrolysis. It can also avoid the errors and residual stress caused by traditional cutting / welding, ensuring the dimensional consistency and array uniformity of the electrode support structure, while reducing manufacturing costs, reducing subsequent processing steps, making it suitable for mass production, and improving the stability and versatility of the finished product.

[0067] To ensure the strength and corrosion resistance of the support plate, in some embodiments, the thickness of the support plate body 11 is 0.2–0.5 mm. The material is N6 pure nickel sheet.

[0068] The electrode support structure design described above for water electrolysis to produce hydrogen significantly improves the contact stability between the electrode and the support structure, enhances structural strength and durability, and optimizes the flow field distribution inside the electrolyzer, thereby improving the overall performance of the electrolyzer. Simultaneously, its ease of installation reduces production costs, making it highly practical and economical, and solving the technical problems of uneven current distribution and low hydrogen production efficiency.

[0069] This utility model also provides an electrolyzer for producing hydrogen by electrolysis of water, including electrodes, a diaphragm, an electrode plate, and the aforementioned electrode support structure for producing hydrogen by electrolysis of water. The electrodes, the electrode support structure for producing hydrogen by electrolysis of water, and the electrode plate are sequentially arranged on both sides of the diaphragm, and the electrodes are attached to the sides of the diaphragm.

[0070] In some embodiments, the main components of the electrolyzer for hydrogen production by water electrolysis have a symmetrical structure. The electrode and diaphragm are bonded together to ensure efficient ion conduction and reduce contact resistance. The electrode support structure, located between the electrode and the electrode plate, provides mechanical support and optimizes electrolyte flow, reducing mechanical stress on the electrode and diaphragm and extending diaphragm life. The electrode plate, acting as a conductive and fluid distribution component, can uniformly distribute the electrolyte and gaseous products.

[0071] The above-described utility model provides an electrode support structure and an electrolyzer for hydrogen production via water electrolysis. The electrode support structure includes a support plate body, a first support portion, and a second support portion. The support plate body has a first surface and a second surface, providing a double-layer structure that can withstand greater pressure and has better resistance to deformation. The first support portion includes multiple first support units located on the first surface. The upper surface of each first support unit has a mounting plane, which increases the effective contact area and contact stability between the electrode and the electrode support structure, reduces contact resistance, and improves current conduction efficiency, thereby increasing electrolysis efficiency. The second support portion includes multiple second support units arranged in an array. Each second support unit has an arched structure with a rebound effect. Elastic deformation ensures a tight fit between the electrode and the diaphragm and absorbs thermal expansion stress during temperature fluctuations, allowing it to better disperse the point of force application when subjected to external forces and avoid structural damage caused by localized stress concentration.

[0072] The electrode support structure design of this utility model for hydrogen production by water electrolysis significantly improves the contact stability between the electrode and the support structure, enhances the structural strength and durability, optimizes the flow field distribution inside the electrolyzer, thereby improving the overall performance of the electrolyzer and solving the technical problems of uneven current distribution and low hydrogen production efficiency.

[0073] Furthermore, the electrode support structure of this novel water electrolysis hydrogen production method is simple in design, easy to install, reduces production costs, ensures controllable finished product quality, and reduces subsequent processing steps, making it suitable for large-scale manufacturing. It possesses high practicality and economic efficiency, and is applicable to various electrolysis hydrogen production systems such as alkaline water electrolysis (ALK) and proton exchange membrane water electrolysis (PEM).

[0074] The above technical solutions of this utility model are merely preferred embodiments and do not limit the patent scope of this utility model. All equivalent structural transformations made under the technical concept of this utility model using the contents of this utility model specification and drawings, or direct / indirect applications in other related technical fields, are included in the patent protection scope of this utility model.

Claims

1. An electrode support structure for hydrogen production by electrolysis of water, characterized by, The electrode support structure (10) includes: The support plate body (11) has a first surface (21) and a second surface (22) disposed opposite to each other along its own thickness direction; and a plurality of through-holes and arrayed first forming holes (31) and second forming holes (32); The first support part (12) includes a plurality of first support units (33) located on the first surface (21), the plurality of first support units (33) being located above the plurality of first forming holes (31) and being arranged in a one-to-one correspondence; the upper surface of the first support unit (33) has a mounting plane; The second support part (13) includes a plurality of second support units (34) located on the second surface (22). The plurality of second support units (34) are located below the plurality of second forming holes (32) and are arranged in a corresponding manner. The second support unit (34) has an arched structure.

2. The electrode support structure for hydrogen production by electrolysis of water according to claim 1, characterized by, The first support unit (33) and the second support unit (34) are arranged in a multi-row array; In some rows, there are N first support units (33) between any two adjacent second support units (34); Where N is an integer, ranging from 4 to 6.

3. The electrode support structure for hydrogen production by water electrolysis according to claim 2, characterized by, The second support units (34) in different rows are arranged in an alternating or parallel manner.

4. The electrode support structure for hydrogen production by water electrolysis according to claim 1, characterized by, The first support unit (33) has a trapezoidal or rectangular cross-section along the height direction; The second support unit (34) is V-shaped or U-shaped, and the connection between the second support unit (34) and the first surface (21) is an arc-shaped transition.

5. The electrode support structure for hydrogen production by water electrolysis according to claim 1, characterized by, The height of the first support unit (33) is 0.8-1.0 mm, the length is 4-6 mm, and the width is 1-2 mm; the spacing of the array of the first support units (33) is 1.5-3.5 mm.

6. The electrode support structure for hydrogen production by water electrolysis according to claim 1, characterized by, The arched structure of the second support unit (34) includes: the height of the arch is 2.4 to 2.6 mm and the width of the arch is 2.5 to 8 mm.

7. The electrode support structure for hydrogen production by water electrolysis according to claim 1, characterized by, The spacing between the support points of the second support unit (34) is greater than the length of the first support unit (33); The first support unit (33) and the second support unit (34) are arranged in an array along the same direction.

8. The electrode support structure for hydrogen production by water electrolysis according to claim 1, characterized by, The electrode support structure (10) is an integrally formed structure; The dimensional tolerance of the electrode support structure (10) is ±0.05mm.

9. The electrode support structure for hydrogen production by water electrolysis according to claim 1, characterized by, The thickness of the support plate body (11) is 0.2 to 0.5 mm.

10. An electrolyzer for hydrogen production by electrolysis of water, characterized in that, The device includes an electrode, a diaphragm, an electrode plate, and an electrode support structure for producing hydrogen by electrolysis of water as described in any one of claims 1 to 9. The electrode, the electrode support structure (10) for producing hydrogen by electrolysis of water, and the electrode plate are sequentially arranged on both sides of the diaphragm, and the electrode is attached to the side of the diaphragm.

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