Electrochemical reactor and method of operating an electrochemical reactor - Patents.com

Abstract

The present invention describes and exemplifies an electrochemical reactor (1), particularly a redox flow battery, fuel cell, electrolyzer, or electrosynthesis cell, comprising a cell stack (Z) comprising a plurality of cells (2) stacked in a stacking direction (R), each separated from one another by at least one bipolar plate (3), where each cell (2) has two electrodes (5, 6) and a separator (10) disposed between the two electrodes (5, 6), and where at least one bipolar plate (3) is flexible. It is specified that an oscillator (13) for oscillating at least one bipolar plate (3) is incorporated within the bipolar plate (3) to improve mass transport and material distribution with low structural and installation costs and low material stress.

Description

[Technical Field]

[0001] The present invention relates to an electrochemical reactor, in particular a redox flow battery, fuel cell, electrolyzer or electrosynthesis cell, comprising a cell stack comprising a plurality of cells separated from one another by at least one bipolar plate and stacked in a stacking direction, each cell having two electrodes and a separator arranged between the two electrodes, and at least one bipolar plate being flexible. The present invention also relates to a method for operating the electrochemical reactor.

[0002] Electrochemical reactors are known in various configurations. In electrochemical reactors, redox reactions take place, which can be driven by an externally applied voltage difference, as is the case during charging of a redox flow battery and during operation of an electrolyzer or electrosynthesis cell. In electrolyzers, a chemical reaction in the form of electrolysis is carried out using an electric current, which produces a product, for example, in the form of hydrogen. In electrosynthesis cells, electrochemical synthesis processes are carried out by applying a voltage to the cell. For example, in electrosynthesis cells, hydrogen peroxide can be synthesized from oxygen and water, or organic base chemicals can be synthesized from carbon dioxide and water. Alternatively, the redox reactions carried out in electrochemical reactors can be used to generate a voltage. This is the case, for example, during discharge of a redox flow battery or during operation of a fuel cell.

[0003] This type of electrochemical reactor typically consists of several electrochemical cells, each performing a different redox reaction. The individual cells of a battery are often arranged in a row or stacked on top of each other, also called a cell stack. Depending on the application, the cell stack facilitates the provision of higher voltages or larger product flows of the products to be produced. Corresponding cell stacks and their uses have been known for a long time from a wide variety of applications and therefore do not need to be described in detail here.

[0004] Individual electrochemical cells are composed of half cells with electrodes separated from each other by separators. The electrodes and separators of the cells are integrated into an internal space provided by at least one cell frame. If necessary, the cells may have multiple cell frames, e.g., one cell frame per half cell of the electrochemical cell. The electrodes, the at least one cell frame, and the separator are arranged at least substantially parallel to each other. This results in a layering structure extending in the so-called stacking direction. The individual cells of the cell stack may be separated from each other by so-called bipolar plates. The anodes and cathodes of adjacent cells are regularly located on opposite sides of the bipolar plates. Furthermore, the anodes and cathodes are typically in direct conductive contact with at least one bipolar plate located between them.

[0005] Although the cell frame and the bipolar plates are typically made of different materials, in some cases, for cost and manufacturing reasons, cell frames and bipolar plates are used that comprise at least one thermoplastic material. To provide sufficient electrical conductivity of the bipolar plates, the bipolar plates often have, in addition to the thermoplastic material, an electrically conductive filler, for example in the form of particulates, such as graphite or carbon black.

[0006] The separator may contain the electrolyte required for the operation of the electrochemical reactor, whereby the separator may have an open-pore porous structure capable of holding a liquid electrolyte. However, it is also possible for the electrodes to be in contact with the electrolyte, whereby the electrolyte and electrodes of the cell are separated by a separator, for example in the form of a membrane. Separators that hold an electrolyte may be used in fuel cells, such as polymer electrolyte membranes (PEMs) or solid oxide fuel cells (SOFCs), whereas electrolytes separated by a separator, for example in the form of a membrane, may be used in redox flow batteries. In the case of redox flow batteries, the electrolyte may flow at least partially through the electrodes.

[0007] In some cases, the separator itself may provide the electrolyte, as in the case of polymer electrolyte fuel cells or solid oxide fuel cells. In such fuel cells, the separator is divided into two sections, with hydrogen-containing gas flowing through one section and oxygen-containing gas flowing through the other section. Gas movement from one section of the separator to the other is prevented by a membrane, which allows the movement of charge carriers. In this configuration, the two sections of the separator and the entire membrane may still be considered a separator between the electrodes. The exact structure of the separator is of limited importance in the context of the present invention. In the case of polymer electrolyte fuel cells, the membrane is made of a solid polymer, while in the case of solid oxide fuel cells, a ceramic oxide electrolyte is used. However, different membranes may be used in different fuel cells, or the membrane may be omitted entirely.

[0008] However, even electrochemical reactors in the form of fuel cells cannot function without fluids. These are working fluids in the form of hydrogen- or oxygen-containing gases that flow through the separators in the anode and cathode compartments. Therefore, care must be taken with electrochemical reactors to ensure that no undesirable fluid leakage occurs during operation. In this case, it is primarily immaterial whether the fluid is an electrolyte or a working fluid.

[0009] Against this background, when manufacturing electrochemical reactors, it is important to ensure their leaktightness. This can be achieved by clamping the cell stack between two end plates. The cells and / or individual parts of the cells are pressed together, thereby providing a seal between the cells and / or individual parts of the cells. On the one hand, this is complicated, and on the other hand, the cells and / or individual parts of the cells must be able to withstand high mechanical forces. To avoid this, it has already been proposed to weld the cells and / or individual parts of the cells together to provide a smaller and more efficient cell stack.

[0010] Mass transport and uniform material distribution within the cell are also crucial to the efficiency of electrochemical reactors. For example, solid deposits or fluid and air inclusions can form within the cell, impeding the mass transport process and ultimately creating electrochemical dead zones that contribute little or nothing to the electrochemical reaction within the cell. Deposits can also adversely affect the cell's lifespan.

[0011] To avoid or eliminate such deposits, it has already been proposed to vibrate the entire cell stack. However, this approach can loosen threaded connections and joints, and expose the cell stack material to significant stress. It has also been proposed to apply vibration to the cell stack from the outside via certain components, but this is complicated in terms of construction and installation. Alternatively, vibration actuators can be integrated into the cell stack, but in this case, these actuators may come into contact with the often corrosive reaction fluids or cause significant stresses in the vibrated components.

[0012] The object underlying the present invention is therefore to construct and further develop an electrochemical reactor and method of the type mentioned at the outset and in more detail above in such a way that mass transport and mass distribution can be improved with low construction and installation costs and low material stresses.

[0013] This object is solved in an electrochemical reactor according to the general subject matter of claim 1 by incorporating within the bipolar plates an oscillator which causes the at least one bipolar plate to oscillate.

[0014] The object is further achieved, according to claim 10, by a method for operating an electrochemical reactor according to any one of claims 1 to 9, - causing at least one oscillator to oscillate at least intermittently; - oscillating at least one bipolar plate by an oscillator; It is solved by the method.

[0015] Thus, according to the present invention, a cell stack is used that includes at least one flexible bipolar plate, which can be vibrated without significant effort or excessive stress on the bipolar plate. Even when vibrations with high amplitudes are generated, the bipolar plate is not destroyed due to its flexibility. Furthermore, the bipolar plate can be easily vibrated, requiring only a low force. Furthermore, due to its flexibility, the vibrations are only transmitted to a limited extent to adjacent components, thereby protecting these components from excessive mechanical stress. In particular, the provided flexibility also allows for precise deformation of the bipolar plate, which means that deposits and air inclusions can be prevented precisely.

[0016] Of course, it is not necessary to continuously oscillate the corresponding bipolar plates, although this is possible and may be preferred. However, it is contemplated that the method oscillates at least one bipolar plate at least intermittently. For example, the oscillation of at least one bipolar plate may be excited occasionally or at regular intervals, thereby dissolving any deposits or air inclusions that have formed and flushing them from the affected half-cell. If the oscillation is at least substantially continuous, it may be possible to prevent the deposits or air pockets from forming in the first place.

[0017] Of course, a cell stack may typically have multiple bipolar plates, and it is not necessary for each of these bipolar plates to incorporate an oscillator. By incorporating oscillators into fewer bipolar plates than necessary or by not oscillating more bipolar plates than necessary, the cost and complexity of the device can be reduced. In this regard, it may be possible to oscillate different bipolar plates at different times, for example, one after the other. If individual bipolar plates cannot be oscillated, it may be useful to oscillate adjacent or closely spaced bipolar plates, thereby transmitting the oscillation of at least one bipolar plate to at least one other bipolar plate or at least one other cell.

[0018] The oscillator is preferably a component capable of causing oscillation of the bipolar plate. However, oscillation of the bipolar plate may nevertheless be induced, i.e., excited, from the outside. Therefore, preferably, an actuator for oscillating the oscillator in at least one bipolar plate is provided outside the actual cell stack. Because the oscillator is integrated into the bipolar plate, oscillation of the oscillator directly oscillates the bipolar plate. In this regard, no actuator is required that is externally contacting the bipolar plate and is otherwise not required for operation of the cell stack.

[0019] With regard to low material stress and avoidance of deposits, it can be particularly useful if the vibrations generated by the at least one oscillator are ultrasonic vibrations, which may have a frequency between 20 kHz and 20 GHz, although other frequencies are also possible.

[0020] In a particularly preferred embodiment of the electrochemical reactor, the oscillator is formed from at least one flexoelectric plastic, at least one hydrogel, at least one shape memory polymer, at least one piezoelectric material and / or at least one magnetostrictive material, which allows a simple and effective integration of the oscillator into the bipolar plate without significantly impairing its electrical function.

[0021] Flexoelectric plastics, such as PVDF, are dielectric plastics that polarize when mechanical loads are applied, and conversely, polarized plastics exert mechanical loads on the plastic. This allows components made of flexoelectric plastic, such as bipolar plates, to be at least partially bent or deformed by applying a voltage. In this case, the bipolar plate does not need to be made entirely of flexoelectric plastic. It may be sufficient for the flexoelectric plastic to constitute a portion of the bipolar plate. The bipolar plate may optionally contain a thermoplastic material and a conductive filler.

[0022] Gel-forming, water-binding, water-insoluble polymers are sometimes called hydrogels. Water absorption can occur physically or chemically. Hydrophilic polymer components contained in bipolar plates, such as sodium polyacrylate or polaxamer, can swell the bipolar plates with a significant volume increase, as is known from so-called superabsorbents. The volume of the bipolar plate can be changed by adding and removing water from the hydrogel. Therefore, by alternating this process at a correspondingly rapid rate, the bipolar plate can be vibrated. If necessary, the bipolar plate can contain thermoplastic materials and conductive fillers in addition to at least one hydrogel.

[0023] As shape memory polymers, polymers with a two-way memory effect, such as those known from shape memory alloys, are particularly suitable. Such shape memory polymers can be, for example, polyurethanes or block copolymers. After being regularly programmed into a specific shape at elevated temperatures, the shape memory polymer can be switched from one shape to another by changing the temperature or a magnetic field. In this case, too, the bipolar plate can be formed only partially from a shape memory polymer, so as not to impair its electrical and mechanical properties. In this case, the bipolar plate can contain, for example, a thermoplastic material and a conductive filler.

[0024] Piezoelectric materials, such as quartz, lithium niobate, gallium orthophosphate, or lead zirconate titanate, exhibit a change in electric polarization and thus the generation of a voltage when elastically deformed (direct piezoelectric effect). Conversely, materials deform when a voltage is applied (inverse piezoelectric effect). When a voltage source is applied to a bipolar plate that at least partially contains a piezoelectric material, varying the voltage can cause the bipolar plate to deform and thus vibrate. When the piezoelectric material is distributed within the bipolar plate, for example, the bipolar plate may comprise a thermoplastic material and a conductive filler.

[0025] Magnetostrictive materials exhibit a property known as magnetostriction, which causes them to deform as a result of the application of a magnetic field. A corresponding object can be elastically alternatingly lengthened (Joule magnetostriction) as a result of the alignment of the magnetic pole regions while maintaining a constant volume. A bipolar plate containing a magnetostrictive material can be vibrated by an alternating magnetic field, even if it is only partially composed of magnetostrictive material. In this case, the bipolar plate may, for example, comprise a thermoplastic material and an electrically conductive filler.

[0026] This allows one of the aforementioned materials to be distributed within the bipolar plate, however, it is also possible to contain such material within the inner space of the bipolar plate, which makes it easier to oscillate the bipolar plate without the oscillation-causing material contacting the electrodes, which may be useful for simpler and / or easier incorporation of the material into the bipolar plate.

[0027] To ensure that the bipolar plate oscillates easily and reliably, it is recommended to connect the oscillator to an activation device. The oscillator itself can therefore be passive, and can be activated via an activation device. Depending on the oscillator, this can be achieved simply by the activation device generating periodic voltage, pressure, and / or temperature changes in the oscillator.

[0028] If necessary, a simple yet effective bipolar plate can be provided by forming the oscillator with at least one internal fluid volume filled with fluid within the bipolar plate. The corresponding fluid volume is variable due to the elasticity of the bipolar plate itself. The corresponding fluid volume is also connected via at least one supply line to a fluid source that can periodically supply and discharge fluid. The supply and discharge of fluid causes the fluid volume within the bipolar plate, and thus the bipolar plate itself, to expand, and then the fluid volume and thus the bipolar plate to contract again. In this way, oscillation of the bipolar plate can be generated.

[0029] For the sake of simplicity and reliability, the oscillator may be provided between at least two electrically connected bipolar plate portions. Therefore, the oscillator can be integrated into the bipolar plate as a separate component or part. It may be particularly advantageous if the at least two bipolar plate portions form a bipolar pad, the oscillator being accommodated in the inner space of the bipolar pad. Thus, the oscillator is accommodated between bipolar plate portions that are electrically connected to each other and each electrically contact one adjacent electrode.

[0030] In principle, it is preferred that at least one bipolar plate, bipolar plate portion, and / or bipolar pad is formed at least primarily from a thermoplastic material and an electrically conductive filler. This allows for simple and cost-effective production of the bipolar plate and high elasticity. This high elasticity supports good vibration behavior of the bipolar plate. Therefore, production is particularly simple and cost-effective when the thermoplastic material is formed at least primarily from polyethylene and / or polypropylene. Alternatively or additionally, for the same reasons, the filler may be formed at least primarily from a carbon-containing material, such as graphite, carbon black, or carbon nanotubes.

[0031] It may be particularly practical and functional if at least one oscillator is an integral component of the bipolar plate, bipolar plate portion, and / or bipolar pad. Therefore, even if no oscillation occurs, the oscillator is not omitted and the functionality of the bipolar plate, bipolar plate portion, and / or bipolar pad is not impaired. This is even more true when the oscillator is incorporated as a dispersed phase within a continuous phase containing a thermoplastic material. As a result, a sufficiently uniform and material-free deformation or oscillation of the bipolar plate can be achieved. Furthermore, a conductive filler may also be incorporated as a dispersed phase within the continuous phase of at least one thermoplastic material.

[0032] To extend the life of the at least one bipolar plate, a bipolar plate having high elasticity may be used. Furthermore, to protect the at least one bipolar plate or cell stack, it is useful for the bipolar plate to be subjected to low-frequency or high-frequency vibrations. Furthermore, to keep material stresses low, excessively high vibration amplitudes are not desirable. However, a certain amplitude may be required to prevent or reduce deposits and / or air inclusions.

[0033] To construct a cell stack that will withstand at least periodic vibrations, it may be useful if at least one separator and / or two electrodes of a cell are housed within a cavity in at least one cell frame, so that the cell stack can be easily stacked, which makes the cell stack more resistant overall.

[0034] In a first particularly preferred embodiment of the method, it is assumed that at least one bipolar plate is formed in the form of a variable-volume bipolar pad. In this case, the volume of the bipolar plate can be changed by supplying and discharging fluid to and from the bipolar plate. This can result in oscillation of the bipolar plate. However, alternatively or additionally, supplying fluid to the bipolar plate can push electrolyte out of at least one half-cell and / or discharging fluid from the bipolar plate can draw electrolyte into at least one half-cell. In other words, changing the volume of at least one bipolar plate can generate a flow of electrolyte within the cell stack. This flow can even transport electrolyte through the cell stack, if desired. If desired, a pump and / or a pressure gradient can be provided to support the flow of electrolyte through the cell stack. However, such a pressure gradient and / or such a pump can be omitted, if desired. In this case, for example, the transport of at least one electrolyte through at least one half-cell may be exclusively influenced by the supply of fluid into and the discharge of fluid from at least one bipolar plate.

[0035] To reduce the electrical resistance in the cell stack, it may be recommended that at least one electrode of the electrochemical reactor is in exclusive contact with at least one thermoplastic resin and / or filler of the bipolar plate, in which case the oscillator may be provided in an area of ​​the bipolar plate facing away from the at least one electrode.

[0036] It is particularly useful if at least one bipolar plate is subjected to low or high frequency oscillation to reduce deposits and / or air inclusions in the cell, which may alternate between phases with low frequency oscillation, high frequency oscillation and / or no oscillation.

[0037] The invention will now be explained in more detail with the aid of drawings which show merely exemplary embodiments. [Brief explanation of the drawings]

[0038] [Figure 1] 1 is a schematic cross-sectional view of one cell stack of an electrochemical reactor according to the present invention, taken along a direction transverse to the stacking direction of cells. [Figure 2] FIG. 2 is a perspective view of a bipolar plate for use in the electrochemical reactor according to FIG. 1. [Figure 3] 2 is a perspective cross-sectional view of an alternative bipolar plate for use in the electrochemical reactor according to FIG. 1; FIG. [Figure 4] 2 is a schematic perspective view of a bipolar plate for use in the electrochemical reactor according to FIG. 1; FIG.

[0039] 1 shows an electrochemical reactor 1 in the form of a redox flow battery with a bipolar structure in cross section from the side. The electrochemical reactor 1 thus comprises a stack (cell stack Z) of individual cells 2 arranged next to each other in a stacking direction R. Between the individual cells 2, a respective bipolar plate 3 is provided, which is located on one side against the negative electrode 5 of the cell 2 and on the other side against the positive electrode 6 of the adjacent cell 2. At the two opposite ends of the electrochemical reactor 1, end plates 7, 8 are provided, each equipped with an internal, electrically conductive arrester plate 9, through which voltage can be extracted from or applied to the electrochemical reactor 1. This is not shown in detail.

[0040] Each cell 2 comprises two electrodes 5, 6, which are separated from each other by a separator 10 disposed between them. In the illustrated electrochemical reactor 1, the two electrodes 5, 6 are in contact with respective electrolytes 11, 12. The electrodes 5, 6 are housed in respective cell frames 12 and are in direct contact with adjacent bipolar plates 3. The cell frames 12 may be fastened together via external fastening devices. However, if necessary, the cell frames 12 can also be welded together across the bipolar plates 3.

[0041] The bipolar plate 3 is connected to an external activation device configured to oscillate an oscillator integrated in the bipolar plate 3. Various designs of the bipolar plate 3 are possible, some of which are described below as examples.

[0042] FIG. 2 shows a bipolar plate 3 in which an oscillator 13 is housed in a matrix of thermoplastic material 14. The thermoplastic material 14 forms a continuous phase in which a filler 15, such as graphite or carbon black, and the oscillator 13 are incorporated as dispersed phases. In this case, the bipolar plate 3 can be set to oscillate or even vibrate by applying a variable external voltage via an external activation device 16 in the form of a voltage source. The oscillation of the bipolar plate 3 is then transmitted to other parts of the cell stack Z. In the case of a redox flow battery, the oscillation is also transmitted to the electrolytes 11, 12, among others. The oscillator 13 is preferably, but not necessarily, made of flexoelectric plastic or piezoelectric material. Alternatively or additionally, the oscillator 13 can be integrated into the bipolar plate 3 as a layer or in the form of a strip. In this case, the remaining part of the bipolar plate 3 can be formed from a mixture of the thermoplastic material 14 and the conductive filler 15.

[0043] 3 shows a bipolar plate 3 with two outer bipolar plate sections 17, which enclose an inner space between them that can be used as a fluid volume 18 for holding a fluid 19 or hydrogel. The fluid volume 18 is connected to an outer activation device 16. The activation device 16 includes a supply line 20 and a pump unit 21 for periodically supplying and expelling fluid 19 into and from the fluid volume 18 of the bipolar plate 3, which is configured as a bipolar pad 22. The oscillator 13 of the bipolar plate 3 is housed in the fluid volume 18. The bipolar plate sections 17 are electrically conductively connected to one another on the one hand, and indirectly connected to one another via the fluid 19 or hydrogel on the other hand.

[0044] 4 shows a bipolar plate 3 with two outer bipolar plate sections 17, between which strips 23 are housed in the bipolar plate 3 with piezoelectric material 24, magnetostrictive material or shape memory polymer. The strips 23 are connected to an outer activation device 16, which applies a varying voltage, a varying magnetic field or a varying temperature to the strips 23, thereby causing the bipolar plate 3 to oscillate. [Explanation of symbols]

[0045] 1. Electrochemical reactor 2 cells 3 Bipolar Plates 5 electrodes 6 electrodes 7 End Plate 8 End Plate 9 Arrester plate 10 Separator 11 Electrolytes 12 Cell Frame 13 Oscillators 14 Plastic 15 Filler 16 Activator 17 Bipolar plate part 18 Volume for fluid 19 Fluid 20 Supply pipeline 21 Pump unit 22 Bipolar Pads 23 Strip 24 Piezoelectric Materials R Stacking direction Z Cell Stack

Claims

1. An electrochemical reactor (1), in particular a redox flow battery, fuel cell, electrolyzer or electrosynthesis cell, comprising a cell stack (Z) comprising a plurality of cells (2) stacked in a stacking direction (R), each separated from each other by at least one bipolar plate (3), each cell (2) having two electrodes (5, 6) and a separator (10) arranged between the two electrodes (5, 6), wherein the at least one bipolar plate (3) is configured to be flexible, Electrochemical reactor (1), characterized in that an oscillator (13) for oscillating said at least one bipolar plate (3) is integrated in said bipolar plate (3).

2. 2. The electrochemical reactor according to claim 1, characterized in that the oscillator (13) is formed by at least one flexoelectric plastic, at least one hydrogel, at least one shape memory polymer, at least one piezoelectric material and / or at least one magnetostrictive material.

3. 3. The electrochemical reactor according to claim 1 or 2, characterized in that the oscillator (13) is connected to an activation device (16), preferably configured to periodically vary the voltage, periodically vary the pressure and / or periodically vary the temperature of the oscillator (13).

4. 4. The electrochemical reactor according to claim 1, wherein the oscillator (13) is formed by at least one internal fluid volume (18) of the bipolar plate (3) filled with a fluid (19), the fluid volume (18) being connected via at least one supply line (20) to a fluid source for cyclically supplying and discharging the fluid (19).

5. 5. The electrochemical reactor according to claim 1, wherein the oscillator (13) is arranged between at least two electrically conductively interconnected bipolar plate portions (17), preferably forming a bipolar pad (22) in an inner space of which the oscillator (13) is housed.

6. 6. The electrochemical reactor according to claim 1, wherein the at least one bipolar plate (3), the bipolar plate portion (17) and / or the bipolar pad (22) are formed at least mainly from a thermoplastic material (14) and an electrically conductive filler (15), preferably wherein the thermoplastic material (14) comprises at least mainly polyethylene and / or polypropylene and / or the filler (15) comprises at least mainly a carbon-containing material, such as graphite, carbon black or carbon nanotubes.

7. 7. The electrochemical reactor according to claim 1, wherein at least one oscillator (13) is an integral part of the bipolar plate (3), the bipolar plate portion (17) and / or the bipolar pad (22), preferably the oscillator (13) is contained as a dispersed phase in a continuous phase comprising a thermoplastic material (24) and a filler (15).

8. 8. The electrochemical reactor according to claim 1, wherein the separator (10) and / or the two electrodes (5, 6) of at least one of the cells (2) are housed in a cavity of at least one cell frame.

9. A method for operating an electrochemical reactor (1) according to any one of claims 1 to 8, comprising: - oscillating at least one of said oscillators (13) at least intermittently; - said oscillator (13) causes said at least one bipolar plate (3) to oscillate; method.

10. - said at least one bipolar plate (3) is made in the form of a variable volume bipolar pad (22); - changing the volume of said bipolar plates (3) by supplying and expelling a fluid (19) to said bipolar plates (3); - by supplying a fluid (19) to push the electrolyte (11) out of at least one half-cell and / or by expelling a fluid (19) to draw the electrolyte (11) into at least one half-cell, 10. The method of claim 9.

11. 11. The method according to claim 10, wherein the transport of at least one electrolyte (11) through the at least one half-cell is exclusively influenced by the supply of a fluid (19) into the at least one bipolar plate (3) and the discharge of a fluid (19) from the at least one bipolar plate (3).

12. The method according to any one of claims 9 to 11, wherein the at least one electrolyte (11) of the electrochemical reactor (1) is exclusively in contact with the at least one thermoplastic material (14) and / or filler (15) of the bipolar plate (3).

13. - Method according to any one of claims 9 to 12, wherein said at least one bipolar plate (3) is subjected to low-frequency or high-frequency oscillations.

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