Battery frame, electrochemical cell and electrochemical flow reactor

Abstract

The invention relates to a cell frame (4) for an electrochemical flow reactor (1), in particular a redox flow cell, the cell frame (4) comprising at least one cell interior (5) in a surrounding manner, the cell frame (4) having at least one flow channel (13, 14) connected to the at least one cell interior (5), at least one flow channel (13, 14) for supplying a fluid to the battery interior (5) and / or for discharging a fluid from the battery interior (5), the at least one flow channel (13, 14) having at least one deflection (17) comprising an arc (18) for deflecting the flowing fluid, in particular at least approximately 90 DEG, wherein the flow channel (13, 14) has an inlet region (19), a deflection region (20), a vortex region (21) and an outlet region (22) in the flow direction of the fluid in sequence, and wherein the flow directions (R1, R2) of the fluid in the inlet region (19) and the outlet region (22) are oriented at least substantially opposite one another. In order to avoid undesired high pressure losses along the flow channel, it is provided that the flow cross-section (QW) of the flow channel (13, 14) in the vortex region (21) is larger than the flow cross-sections (QE, QA) in the inlet region (19) and in the outlet region (22).

Description

Technical Field

[0001] The present invention relates to a cell frame for an electrochemical flow reactor, in particular a redox flow battery, wherein the cell frame circumferentially encompasses at least one cell interior, wherein the cell frame has at least one flow channel connected to the at least one cell interior for conveying a fluid into the cell interior and / or discharging a fluid from the cell interior.

[0002] The at least one flow channel has at least one deflection portion comprising an arc for deflecting the flowing fluid, in particular by at least approximately 90 degrees, wherein the flow channel comprises an inlet region, a deflection region, a vortex region, and an outlet region in sequence along the flow direction of the fluid, and wherein the flow directions of the fluid in the inlet region and the outlet region are oriented at least substantially opposite to one another. Furthermore, the present invention relates to an electrochemical cell for a flow reactor, in particular a redox flow battery, comprising at least one such cell frame, and to an electrochemical flow reactor, in particular a redox flow battery, comprising such a cell. Background Art

[0003] Various designs of electrochemical cells are known, and some are also referred to as electrochemical reactors because the electrochemical reaction takes place within them. Depending on their application, electrochemical cells can be designed, for example, as galvanic cells in the form of electrochemical power sources, which provide usable electrical energy via chemical reactions at various electrodes. Alternatively, however, electrochemical cells can also be used to produce specific products by applying an external voltage. In this case, storage cells, like galvanic cells, alternately serve as power sources and as energy storage devices.

[0004] The present invention can be used for all types of electrochemical cells through which at least one fluid flows. In this context, cells are also referred to as electrochemical flow reactors. Such electrochemical flow reactors are, for example, fuel cells, electrolysis cells, electrosynthesis cells, and redox flow batteries.

[0005] A fuel cell is passed through a working fluid, which can be a liquid or gaseous medium. This working fluid flows through an anode chamber and a cathode chamber, which are separated by a separator. The anode chamber and cathode chamber are typically provided by a cell frame, which closes the cell interior to the outside in the plane of the cell frame. Contrary to its common name, a fuel cell is typically constructed as a battery pack with multiple electrochemical cells stacked one on top of the other. An electrolyzer comprises a series of electrolysis cells, which can also be integrated into a battery pack. With the help of an electric current, a chemical reaction in the form of electrolysis occurs in each electrochemical cell to produce a product, such as hydrogen. An electrosynthesis cell is constructed similarly to an electrochemical cell in an electrolyzer. However, the fundamental difference is that the eductants are not separated electrochemically. Rather, a synthesis reaction occurs. Depending on the desired reaction and therefore the corresponding eductants and products, the cell interior of the corresponding electrochemical cell half-cell, separated by a separator, is passed through by a liquid or gaseous medium. In this case, the battery interiors are also typically provided essentially by the battery frame, which closes the individual battery interiors to the outside in the plane of the battery frame.

[0006] In batteries, such as redox flow batteries, redox reactions carried out in electrochemical reactors can be used to generate voltage. However, redox flow batteries can also be recharged by applying an external voltage, so redox flow batteries are essentially storage batteries. Redox flow batteries themselves are already known and have various embodiments. These embodiments are described, for example, in EP 0 051 766 A1 and US 2004 / 0170893 A1. A key advantage of redox flow batteries is their flexible scalability of power and capacity, allowing them to store very large amounts of energy even with lower performance, and vice versa. Energy is stored in an electrolyte, which can be stored in an external tank. The electrolyte typically contains metal ions in different oxidation states. To extract electrical energy from the electrolyte or to recharge it, the electrolyte is pumped through a so-called electrochemical cell. The structure of a redox flow battery is generally less well-known than that of the other electrochemical reactors mentioned above, although the structures of different electrochemical reactors are essentially similar. Therefore, the structure of a redox flow battery will be discussed in detail below as an example.

[0007] The electrochemical cell of a redox flow battery is usually composed of two half-cells, which are separated from each other by a separator in the form of a semi-permeable membrane and each of which has an electrolyte and an electrode. The semi-permeable membrane has the following task, namely, to separate the cathode and anode of the electrochemical cell spatially and electrically from each other. Therefore, the semi-permeable membrane must allow ions to pass through, and the ions convert the stored chemical energy into electrical energy, and vice versa. The semi-permeable membrane can be composed of, for example, microporous plastic, non-woven fabrics made of glass fiber or polyethylene, and so-called diaphragms. Redox reactions take place at the two electrodes of the electrochemical cell, wherein electrons are released by the electrolyte at one electrode and absorbed at the other electrode. The metal and / or non-metal ions of the electrolyte form redox pairs and thus generate a redox potential. As redox pairs, for example, iron-chromium, polysulfide-bromide or vanadium can be considered. These or other redox pairs can, in principle, be present in aqueous or non-aqueous solutions.

[0008] The electrodes of a battery (between which a potential difference is formed due to the redox potential) are electrically connected to each other outside the battery, for example, via an electrical consumer. Electrons outside the battery pass from one half-cell to the other, while ions of the electrolyte cross directly from one half-cell to the other through a semipermeable membrane. To recharge a redox flow battery, a potential difference can be applied to the electrodes of the half-cells, for example, using a charger (rather than an electrical consumer). This potential difference reverses the redox reaction occurring at the electrodes of the half-cells.

[0009] To construct these batteries, a cell frame is primarily used, which surrounds the battery interior. The cell frame typically does not completely surround the battery interior, but rather only along the narrow sides of the perimeter. Consequently, the cell frame extends circumferentially around the battery interior and separates two opposing side surfaces of greater area from one another, which in turn are assigned to the semipermeable membrane or electrodes. The thickness of the cell frame, formed by its edges, is typically significantly smaller than the width and height of the cell frame, which define the opposing side surfaces of greater area.

[0010] Each half-cell of an electrochemical cell includes such a cell frame, which is made of thermoplastic, for example, by injection molding. A semi-permeable membrane is arranged between the two cell frames, which separates the electrolytes of the half-cells from each other from the perspective of convective mass exchange, but allows specific ions to diffuse from one half-cell to the other half-cell. In addition, these cell chambers are each assigned electrodes so that these electrodes are in contact with the electrolyte flowing through the cell chamber. For example, the electrodes can close the cell chamber of each cell frame on the side away from the semi-permeable membrane. In this case, the cell chamber can remain essentially empty and be filled only with the electrolyte. However, each electrode can also be at least partially arranged in the cell chamber. Then, the electrodes are typically configured so that the electrolyte can partially flow through the electrodes.

[0011] In this case, electrodes with a high specific surface area are often considered, on which the corresponding electrochemical reaction can proceed correspondingly quickly and / or comprehensively. This ultimately leads to a battery with a high volumetric power ratio. However, when the electrodes extend into the battery compartment, the battery compartment is mostly closed by the electrodes on the side facing away from the semi-permeable membrane. So-called bipolar plates can also be considered as non-porous parts of the electrodes, which can be coated with catalysts or other substances, for example. Each battery frame has openings and channels through which the corresponding electrolyte can flow from the supply line into the corresponding battery compartment and from there be withdrawn again and fed to the removal line.

[0012] If the redox flow battery consists of only a single cell, a supply line for each half-cell and a purge line for each half-cell are located outside the cell frame that forms the half-cell. Each cell frame has at least two openings, at least one of which is connected to the supply line, and at least one other opening is connected to the purge line. Inside the cell frame, each opening is connected to a flow channel that opens into the cell interior. This allows electrolyte to be transported from the supply line into the cell interior via the delivery channel and electrolyte flowing through the cell interior to be discharged via the discharge channel. The flow channel can also be designed to branch.

[0013] Multiple electrochemical cells of the same type are combined to form a redox flow battery, as needed. To achieve this, the cells are typically stacked one on top of the other, resulting in the battery stack being referred to as a cell stack or battery pack. The electrolyte typically flows through the individual cells in parallel, while the cells are typically connected electrically one after the other. Consequently, the cells are typically hydraulically connected in parallel and electrically connected in series. In this case, the electrolyte's state of charge is the same in each half-cell of the stack. To distribute the electrolyte to the corresponding half-cells in the stack and to collectively remove the electrolyte from each half-cell, the half-cells are interconnected by supply and purge lines. Because each half-cell or each cell compartment of the battery has a different electrolyte flowing through it, the two electrolytes must be separated from each other as they pass through the stack. Therefore, two separate supply lines and two separate purge lines are typically provided along the stack. Each of these channels is typically formed partially by the cell frame itself, which has four openings for this purpose. These openings extend along the stack, arranged one after the other and separated from each other by sealing material as needed, forming the supply and purge lines.

[0014] In many cases, the flow channels for conveying fluids into and out of the battery interior are at least partially arranged in a meandering shape within the associated battery compartment. Here, the battery frame can have the flow channels as closed channels, thus completely comprising the flow channels, or it can also have only open channels that are closed by at least one other component when the battery frame is connected to other components of the battery. However, this distinction is not crucial here, so it will not always be discussed in detail below. This is intended to facilitate understanding and avoid unnecessary repetition.

[0015] Most winding circulation channels have multiple arcs, which are used to reverse the circulation direction. The circulation direction is usually reversed 180° here. However, this precise circulation reversal is not important here. Alternatively or additionally, a deflection portion can be used to make the circulation direction turn approximately at a right angle, that is, approximately at 90°. In order to turn and / or reverse the circulation direction, the deflection portion of the circulation channel has an arc. This applies to situations where the circulation direction turns approximately 90°, the circulating fluid reverses approximately 180° to the opposite direction, or the circulation direction turns within an angular range between the two. These deflections can be divided into different sections along the circulation direction, and these sections can be directly connected to each other, but this is not mandatory. In the inlet area, the fluid is transported to the deflection area with the original circulation direction, where the actual deflection of the circulation direction is achieved, and the deflection area includes an arc for this purpose. From the arc or deflection area, the flow reaches the vortex area, where the reversal of the circulation direction can have ended, but this is not necessary. In this vortex area, vortexing of the flow usually occurs. In the outlet region, the deflection of the flow direction is at least substantially completed, so that the deflected flow direction in the outlet region points in another direction, optionally at least substantially in the opposite direction to the original flow direction in the inlet region.

[0016] The meandering design of the flow channel allows the deliberately lengthened path of the flow channel (in order to increase the resistance through the fluid line and thereby reduce the short-circuit current between the hydraulically connected half-cells in the battery pack) to be positioned in the battery frame in a very space-saving manner. However, this has the disadvantage that relatively high and undesirable pressure losses must be tolerated, partially along the flow channel. Summary of the Invention

[0017] The object of the present invention is therefore to design and improve a cell frame, an electrochemical cell and an electrochemical flow reactor of the type mentioned at the outset and explained in detail above, in each case, in such a way that undesirably high pressure losses along the flow channels are avoided.

[0018] This object is achieved in a cell frame according to the preamble of claim 1 in that the flow cross section of the flow channel in the eddy flow region is larger than the flow cross section in the inlet region and in the outlet region.

[0019] Furthermore, the object is achieved according to claim 12 by an electrochemical cell for a flow reactor, in particular a redox flow battery, which comprises at least one cell frame according to any one of claims 1 to 11 .

[0020] Furthermore, the aforementioned object is achieved according to claim 14 by an electrochemical flow reactor, in particular a redox flow battery, which has at least one cell according to claim 12 or 13 .

[0021] The present invention recognizes that when the flow cross section of the circulation channel in the vortex area is constructed to be larger than not only the flow cross section in the inlet area but also than the flow cross section in the outlet area, the pressure loss generated by the deflection in the tortuous circulation channel can be reduced. The flow cross sections in the inlet area and in the outlet area are preferably constructed at least substantially identically. Here, the flow cross section is selected so that the tortuous circulation channel does not require too much space and at the same time does not generate too high a pressure loss. Usually, a small flow cross section can be provided here because the pressure loss is mainly generated by the deflection of the flow direction in the deflection portion of the circulation channel. However, in order to reduce this pressure loss, it is not necessary to increase the flow cross section in the deflection area. On the one hand, this requires more structural space, and on the other hand, due to the change in cross section, the flow is first braked and then accelerated, which itself may increase the pressure loss of the flow. Nevertheless, the present invention recognizes that targeted expansion of the circulation channel can help reduce the pressure loss without significantly increasing the space requirement of the circulation channel.

[0022] The flow cross section of the flow channel is increased precisely in the eddy flow region of the flow channel because, due to the presence of the curved portion there, particularly on the inner side of the flow channel, an eddy flow zone is formed in the flow. This eddy flow zone reduces the flow cross section of the portion of the flow that is less eddy or not eddying, which is therefore first accelerated and then braked adjacent to the eddy flow zone. By increasing the flow cross section in the region of the eddy flow zone, a substantially constant flow cross section is provided for the portion of the flow that is less eddy or not eddying, despite the presence of the eddy flow zone. Consequently, due to the eddy flow zone in the eddy flow region of the flow channel, this portion of the flow is not braked and / or accelerated, or only slightly, which ultimately leads to a reduction in the overall pressure loss of the flow. With regard to the fluid dynamics of the flow channel and the space required for the flow channel in the battery frame, it has proven particularly advantageous if the flow cross section in the eddy flow region is at least 10%, preferably at least 20%, and in particular at least 30% larger than the flow cross section in the inlet region and / or outlet region.

[0023] The battery frame preferably has two different flow channels for conveying the relevant fluids into and out of the battery interior. It is therefore advantageous for the two flow channels to be constructed in a manner similar to that described above. However, this is not mandatory, just as the battery frame is not limited to a maximum of two such flow channels. For example, to achieve uniform distribution of the fluid within the battery interior, it is conceivable to provide multiple flow channels for conveying the fluid into the battery interior and for conveying the fluid out of the battery interior. However, alternatively or additionally, the flow channels may also branch so that the fluid can be introduced into and / or discharged from the battery interior over a wider area.

[0024] The advantages of the present invention are particularly effective for deflections in which the flowing fluid is deflected at a rate of at least approximately 90°, i.e., at at least approximately a right angle, but not exclusively. However, angles significantly less than a right angle, or 90°, are also possible. Even in this case, more or less meandering flow channels can be formed that prevent short-circuit currents.

[0025] In a particularly preferred first embodiment of the battery frame, the deflection portion, comprising an arc, for deflecting the circulating fluid is designed so that it serves to deflect the circulating fluid at approximately a right angle or at approximately 90°. This makes it possible to provide a relatively long flow channel in the battery frame in a simple manner. However, it is not necessarily important whether the deflection occurs at a right angle or only approximately at a right angle. However, for embodiments of the flow channel designed as a meander, it can be particularly preferred that the deflection portion is at least essentially designed to reverse the circulating fluid in the opposite direction. In this case, it is also preferred, but by no means mandatory, that the flow direction is actually reversed by at least essentially 180°. If this is beneficial for the design of the flow channel, a deflection portion with an angle between 90° and 180° can also be provided.

[0026] In a common center plane, the width of the flow channel in the vortex region is configured to be greater than the width of the flow channel in both the inlet region and the outlet region. The center plane intersects the inlet region, the deflection region, the vortex region, and the outlet region. It is particularly preferred that the common center plane intersect the inlet region, the deflection region, the vortex region, and the outlet region in the center region of the flow channel and / or in the centerline region of the flow channel, respectively. Therefore, the widening of the flow cross section in the vortex region compared to the inlet and outlet regions is implemented such that, in the common center plane, the flow channel is wider in the vortex region than in the inlet and outlet regions. This ultimately results in a flow channel having an overall preferred shape in terms of fluid dynamics. With respect to the fluid dynamics of the flow channel and the space required for the flow channel in the battery frame, it has proven particularly advantageous that, in the common center plane, the width of the flow channel in the vortex region is at least 10%, preferably at least 20%, and in particular at least 30% wider than the width in the inlet and / or outlet regions.

[0027] Alternatively or additionally, if the flow cross section of the flow channel in the eddy region is larger than the flow cross section in the deflection region, this contributes to reducing pressure losses through the flow channel overall. This allows the flow channel to expand slowly in a fluidically advantageous manner, which particularly preferably occurs in conjunction with the formation of eddy regions in the flow channel. This also prevents or reduces flow interruptions on the outer sides of the flow channel. The difference in the flow cross sections between the eddy region and the deflection region is preferably at least 10%, more preferably at least 15%, and in particular at least 20%.

[0028] Independently of this, in a common center plane, the width of the flow channel in the eddy region can be greater than the width of the flow channel in the deflection region. In this case, the aforementioned fluid dynamic advantages are also achieved without the flow channel itself requiring significantly more space. The difference in width between the flow channel in the eddy region and in the deflection region is preferably at least 10%, more preferably at least 15%, and in particular at least 20%.

[0029] Alternatively or additionally, the distance between the inlet and outlet regions, viewed in a common center plane transversely to the flow direction in the inlet region, can be smaller than the width of the inlet and / or outlet regions. This allows for a space-saving arrangement of meandering flow channels without necessarily resulting in excessive pressure losses. The aforementioned dimensional differences are preferably at least 10%, more preferably at least 15%, and in particular at least 20%.

[0030] If the spacing between the inlet and outlet regions (as viewed transversely to the flow direction in the inlet region) in a common center plane is greater than the spacing between the inlet and eddy regions (also as viewed transversely to the flow direction in the inlet region), the space required for the flow channel can be reduced. Contrary to expectations, the flow cross section in the eddy region can be increased by sacrificing the corresponding spacing between the inlet and eddy regions without thereby compromising the overall reduction in pressure losses. The difference in the spacings is preferably at least 10%, more preferably at least 15%, and in particular at least 20%.

[0031] Furthermore, a good compromise between pressure loss and the space required for the flow channel can be achieved if the inner radius of the deflection region, viewed in a common center plane and transversely to the flow direction in the inlet region, is greater than the distance between the inlet region and the eddy region. A larger inner radius reduces the tendency for flow interruption and the subsequent formation of wider eddy regions. Contrary to expectations, the return of the eddy region to the inlet region does not compromise this, but can advantageously serve to reduce the overall space required for the flow channel. The corresponding inner radius is preferably at least 10%, more preferably at least 15%, and in particular at least 20% greater than the corresponding distance.

[0032] Alternatively or additionally, the inner radius of the deflection region, viewed in a common center plane transversely to the flow direction in the inlet region, can be larger than the distance between the inlet region and the outlet region. In this case, the aforementioned fluid dynamic advantages are also achieved without requiring significantly more space in the flow channel itself. The respective inner radius is preferably at least 10%, more preferably at least 15%, and in particular at least 20% larger than the respective distance.

[0033] Alternatively or additionally, a flow channel that is fluidically advantageous and simultaneously requires minimal space can be achieved if, within a common center plane, the width of the deflection in the deflection region (viewed transversely to the flow direction in the inlet region) is greater than its width at the level of the outlet region. The greater width in the deflection region primarily serves to reduce pressure losses, while the smaller spacing between the inlet and outlet regions contributes to a smaller space requirement, without these two measures excessively interfering with each other. This can be exploited even more comprehensively if, within a common center plane, the width of the deflection in the deflection region (viewed transversely to the flow direction in the inlet region) is greater than its width at the level of the eddy flow region. Thus, the eddy flow region can not only contribute to reducing pressure losses but also to reducing the space requirement of the flow channel. The respective width differences are preferably at least 10%, more preferably at least 15%, and in particular at least 20%.

[0034] If, in a common center plane, the width of the deflection at the level of the eddy flow region (viewed transversely to the flow direction in the inlet region) is greater than the width at the level of the outlet region, this can result in a flow with lower pressure losses. At the same time, however, the flow channel can be designed such that the space required for the flow channel remains small. The respective width differences are preferably at least 10%, more preferably at least 15%, and in particular at least 20%.

[0035] If the width of the eddy flow region, transversely to the flow direction in the inlet region, in the common center plane is greater than one and a half times the width of the inlet region and / or outlet region, the space requirement of the flow channel can also be kept small without unduly affecting the pressure losses in the flow channel. Depending on the requirements, the space requirement is then only slightly greater than in the case of a standard deflection with a constant flow cross section.

[0036] In a particularly preferred first embodiment of the electrochemical cell, at least one cell frame according to any one of claims 1 to 11 is provided for each half-cell. In this way, the aforementioned advantages can be utilized to a particularly high degree, in particular in two half-cells of the electrochemical cell.

[0037] In a particularly preferred first embodiment of the electrochemical flow reactor, a battery is provided consisting of electrochemical cells according to claim 12 or 13. Overall, this results in an electrochemical flow reactor having a high power density and efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] The invention is explained in more detail below with the aid of the accompanying drawings which show only one exemplary embodiment.

[0039] It shows:

[0040] Figures 1A-1B The electrochemical flow reactor according to the invention in the form of a redox flow battery is shown in longitudinal section,

[0041] Figure 2 The cell frame of the electrochemical flow reactor according to the invention according to FIG. 1 is shown in a top view, and

[0042] Figure 3 Shown in top view Figure 2 The turning portion of the flow channel of the battery frame. DETAILED DESCRIPTION

[0043] exist Figure 1A and Figure 1B, an electrochemical flow reactor 1 in the form of a redox flow battery is shown in longitudinal section. The reactor comprises a cell stack or group containing a plurality of electrochemical cells 2. The electrochemical flow reactor 1 includes three cells 2, each of which has two half-cells 3 with corresponding electrolytes. Each half-cell 3 has a cell frame 4, which includes a cell interior 5 through which the electrolyte stored in a storage container can be passed. An electrode 6 at least partially engages the cell interior 5 and, in addition, closes and seals the cell interior 5 on one side. The electrolytes flowing through the cell interior 5 are different from one another. Each cell interior 5 is closed on the side facing away from the electrode 6, at the cell frame 4 of the second half-cell 3 of the same electrochemical cell 2, by a semipermeable membrane 7 disposed between the cell frames 4 of the two half-cells 3. This prevents convective transfer of the two different electrolytes of the two half-cells 3 into the cell interior 5 of the cell frame 4 of the other half-cell 3. However, ions can be transferred from one electrolyte to another by diffusion through a semipermeable membrane 7, thereby enabling charge transport. Electrons are released or absorbed by the electrolyte redox pairs at the electrodes 6 of the half-cell 3 of one cell 2 through a redox reaction. The released electrons can flow from one electrode 6 of one cell 2 to the other via electrical connections provided outside the flow reactor 1, optionally with electrical consumers. Which reactions occur at which electrodes 6 depends on whether the electrochemical flow reactor is being charged or discharged.

[0044] In the illustrated electrochemical flow reactor 1, the electrodes 6 lie flat on the outer sides 8 of the cell frames 4. Thus, in the areas where they abut against the outer sides 8 of the cell frames 4, the electrodes 6 form frame surfaces that function as sealing surfaces 9. A sealing material 10 is located between the mutually facing outer sides 8 of the cell frames 4 of a cell 2, in which the diaphragm 7 is sealed. The sealing material 10 abuts flat against the outer sides 8 of the adjacent cell frames 4 and thus forms frame surfaces that function as sealing surfaces 9.

[0045] Four channels extend along the electrochemical flow reactor 1. Two of the channels are supply lines 11, which are used to transport two electrolytes to the cell inner chamber 5 of the cell frame 4. The other two channels are purge lines 12, which are used to remove electrolytes from the cell inner chamber 5 of the cell frame 4. Figure 1A1 and 2. A supply line 11 and a purge line 12 are shown in each figure. A flow channel 13 as a transport channel branches out from the supply line 11 to each half cell 3 of each battery 2, through which the electrolyte can be transported to the corresponding cell interior 5 of the half cell 3. A flow channel 14 as a discharge channel is provided on the opposite section of the corresponding cell frame 4, through which the electrolyte can be discharged from the cell interior 5 to the purge line 12. Figure 1A A supply line 11 (not shown) and a purge line 12 (also not shown) enable the second electrolyte to flow through the other cell interior 5 of the other half-cell 3 via flow channels 13 , 14 of the same type.

[0046] exist Figure 2 , a top view of the battery frame 4 is shown. Four openings 15 are provided at the corners of the battery frame 4, wherein each opening 15 forms part of a supply line 11 or a purge line 12. The flow channels 13 for transporting the electrolyte and the flow channels 14 for discharging the electrolyte are embedded as recesses or open channels in the outer side 8 of the frame shell 16 of the battery frame 4 that surrounds the battery inner chamber 5. These flow channels 13, 14 are closed into pipelines that are closed on the circumferential side when assembled into the electrochemical flow reactor 1. In the electrochemical flow reactor 1 shown, this is achieved, for example and in part, by means of a sealing material 10 and an electrode 6. However, the flow channels 13, 14 can also be provided in the battery frame as closed channels, or be closed by other components of the electrochemical flow reactor 1.

[0047] These flow channels 13, 14 are Figure 2 1 is shown only very schematically and, in the illustrated embodiment, is branched so that the electrolyte can be supplied in a dispersed manner to the cell interior 5 via a flow channel 13 and discharged in a dispersed manner via another flow channel 14. However, this is not essential. Therefore, flow channels 13, 14 running separately from the supply line 11 can also be provided.

[0048] The flow channels 13, 14 are designed in a meandering manner with a plurality of deflections 17, wherein one deflection 17 is at Figure 3, which is shown in detail as an example. The deflection portion 17 includes an arc portion 18, which is used to at least substantially reverse the original flow direction R1 of the liquid flow in the flow channels 13, 14 into the opposite flow direction R2 after passing through the arc portion 18. The deflection portion 17 is divided into four different sections, which are arranged in sequence along the flow directions R1, R2 of the fluid (in this embodiment, the electrolyte). In the inlet area 19, the fluid is conveyed along the original flow direction R1 to the deflection area 20, so that the flow direction R1 of the circulating fluid is actually deflected. Therefore, in the deflection area 20, the liquid flow is deflected and leaves the deflection area 20 in a flow direction that is at least partially opposite to the original flow direction R1. Due to this deflection, eddy flow zones are formed in the liquid flow, especially on the inner sides of the flow channels 13, 14, and these eddy flow zones are at least substantially present in the eddy flow area 21. After the eddy zone has at least largely subsided, the outlet region 22 connects to the eddy zone 21. In this outlet region, the redirected flow direction R2 is at least substantially directed opposite to the original flow direction R1. The flow direction R2 can be redirected 180°. However, a precise reversal of the flow direction is not necessary. In the illustrated and, to this extent, preferred embodiment, it is sufficient for the flow to flow back approximately in the direction from which it originally flowed. This is how the meandering design of the flow channels 13 and 14 is achieved.

[0049] exist Figure 3 In the deflection 17 of the flow channels 13, 14 shown in FIG, the flow cross section QW of the flow channels 13, 14 in the eddy region 21 is greater not only than the flow cross section QE in the inlet region 19 but also than the flow cross section QA in the outlet region 22. In the common center plane ME, the width BW of the flow channels 13, 14 in the eddy region 21 is greater not only than the width BE of the flow channels 13, 14 in the inlet region 19 but also than the width BA of the flow channels 13, 14 in the outlet region 22.

[0050] Here, the common center plane ME intersects the inlet region 19, the deflection region 20, the eddy region 21, and the outlet region 22, more precisely, in the center region of the flow channels 13, 14 and / or in the region of the center line ML of the flow channels 13, 14. Furthermore, the flow cross section QW of the flow channels 13, 14 in the eddy region 21 is designed to be larger than the flow cross section QU in the deflection region 20.

[0051] As viewed in a direction transverse to the flow direction R1 in the inlet region 19, in a common center plane ME, the width BW of the flow channels 13, 14 in the eddy region 21 is greater than the corresponding width BU of the flow channels 13, 14 in the deflection region 20. Furthermore, as viewed in a direction transverse to the flow direction R1 in the inlet region 19, in the common center plane ME, the spacing A1 between the inlet region 19 and the outlet region 22 is smaller than the widths BE, BA, of the inlet region 19 and the outlet region 22. As viewed in the common center plane ME, also transverse to the flow direction R1 in the inlet region 19, the spacing A1 between the inlet region 19 and the outlet region 22 is greater than the corresponding spacing A2 between the inlet region 19 and the eddy region 21.

[0052] Furthermore, when the respective distances A1, A2 are measured transversely to the flow direction R1 in the inlet region 19 along the common center plane ME, the inner radius IR of the deflection region 20 in the common center plane ME is greater than the distance A2 between the inlet region 19 and the eddy region 21, and greater than the distance A1 between the inlet region 19 and the outlet region 22. Measured in the same direction, the widths B1, B2 of the deflection portion 17 in the deflection region 20 and the eddy region 21, respectively, are greater than the width B3 of the deflection portion 17 at the level of the outlet region 22, and the width B1 of the deflection portion 17 in the deflection region 20 transversely to the flow direction R1 in the inlet region 19 is greater than the width B2 of the deflection portion at the level of the eddy region 21. Furthermore, as viewed in the common center plane ME transversely to the flow direction R1 in the inlet region 19, the width BW of the eddy region 21 is greater than one and a half times the widths BE, BA of the inlet region 19 and / or the outlet region 22.

[0053] Description of Reference Numerals

[0054] 1 Flow reactor

[0055] 2 batteries

[0056] 3 half-cells

[0057] 4 battery frame

[0058] 5Battery compartment

[0059] 6 electrodes

[0060] 7Semi-permeable membrane

[0061] 8 outside

[0062] 9 Sealing surface

[0063] 10 Sealing materials

[0064] 11 Supply pipeline

[0065] 12 Clear the pipeline

[0066] 13 circulation channels

[0067] 14 circulation channels

[0068] 15 openings

[0069] 16 frame housing

[0070] 17 Steering

[0071] 18 arc

[0072] 19 Entrance Area

[0073] 20 Turning area

[0074] 21 Eddy current area

[0075] 22Exit Area

[0076] A1-A2 spacing

[0077] B1-B3 Width of the turning section

[0078] Width of BA outlet area

[0079] Width of BE entrance area

[0080] Width of BU turning area

[0081] BW eddy current width

[0082] IR inner radius

[0083] ME center plane

[0084] Flow cross section in the QA outlet area

[0085] Flow cross section in the QE inlet area

[0086] Flow cross section in the QU turning area

[0087] Flow cross section in the QW vortex region

[0088] R1 original flow direction

[0089] R2 turns the flow direction

Claims

1. A cell frame (4) for an electrochemical flow reactor (1), in particular a redox flow battery, wherein: The battery frame (4) circumferentially comprises at least one battery interior (5), wherein the battery frame (4) has at least one flow channel (13, 14) connected to the at least one battery interior (5) for conveying a fluid into the battery interior (5) and / or for discharging a fluid from the battery interior (5), wherein at least one flow channel (13, 14) has at least one deflection portion (17) comprising an arc (18) for deflecting the flowing fluid, in particular by at least approximately 90 degrees, wherein the flow channel (13, 14) has, in sequence along the flow direction of the fluid, an inlet region (19), a deflection region (20), a vortex region (21) and an outlet region (22), and wherein the flow directions (R1, R2) of the fluid in the inlet region (19) and the outlet region (22) are oriented at least substantially opposite to one another. It is characterized in that The flow cross section (QW) of the flow channel (13, 14) in the eddy flow region (21) is larger than the flow cross sections (QE, QA) in the inlet region (19) and in the outlet region (22).

2. The battery frame according to claim 1, characterized in that A deflection portion (17) comprising an arc portion (18) is provided for deflecting the flowing fluid approximately at a right angle, preferably at least substantially for reversing the flowing fluid into the opposite direction.

3. The battery frame according to claim 1 or 2, characterized in that: In a common center plane (ME), the width (BW) of the flow channels (13, 14) in the eddy region (21) is greater than the width (BA, BE) of the flow channels (13, 14) in the inlet region (19) and the outlet region (22), and / or the flow cross section (QW) of the flow channels (13, 14) in the eddy region (21) is greater than the flow cross section (QU) in the deflection region (20).

4. The battery frame according to any one of claims 1 to 3, characterized in that: In a common center plane (ME), a width (BW) of the flow channels (13, 14) in the eddy region (21) transverse to the flow direction (R1) in the inlet region (19) is greater than a width (BU) of the flow channels (13, 14) in the deflection region (20) transverse to the flow direction (R1) in the inlet region (19).

5. The battery frame according to any one of claims 1 to 4, characterized in that: In a common center plane (ME), a distance (A1) between the inlet region (19) and the outlet region (22) transverse to the flow direction (R1) in the inlet region (19) is smaller than the widths (BA, BE) of the inlet region (19) and the outlet region (22), respectively, transverse to the flow direction (R1) in the inlet region (19).

6. The battery frame according to any one of claims 1 to 5, characterized in that: In a common center plane (ME), a distance (A1) between the inlet region (19) and the outlet region (22) transversely to the flow direction (R1) in the inlet region (19) is greater than a distance (A2) between the inlet region (19) and the eddy region (21) transversely to the flow direction (R1) in the inlet region (19).

7. The battery frame according to any one of claims 1 to 6, characterized in that: In the common center plane (ME), the inner radius of the deflection region (20) is greater than the distance (A2) between the inlet region (19) and the eddy flow region (21) transversely to the flow direction (R1) in the inlet region (19).

8. The battery frame according to any one of claims 1 to 7, characterized in that: In the common center plane (ME), the inner radius of the deflection region (20) is greater than the distance (A1) between the inlet region (19) and the outlet region (22) transversely to the flow direction in the inlet region (19).

9. The battery frame according to any one of claims 1 to 8, characterized in that: In the common center plane (ME), the width (B1) of the turning portion in the turning area (20) transverse to the flow direction (R1) in the inlet area (19) is greater than the width at the level of the outlet area (22), and preferably, in the common center plane (ME), the width (B1) of the turning portion in the turning area (20) transverse to the flow direction (R1) in the inlet area (19) is greater than the width at the level of the vortex area (21).

10. The battery frame according to any one of claims 1 to 9, characterized in that: In the common center plane (ME), the width (B2) of the turning portion at the level of the vortex region (21) transverse to the flow direction (R1) in the inlet region (19) is greater than the width (B3) of the turning portion at the level of the outlet region (22) transverse to the flow direction (R1) in the inlet region (19).

11. The battery frame according to any one of claims 1 to 10, characterized in that: In the common center plane (ME), the width (B2) of the eddy region (21) transversely to the flow direction (R1) in the inlet region (19) is greater than one and a half times the width (BE, BA) of the inlet region (19) and / or the outlet region (22) transversely to the flow direction (R1) in the inlet region (19).

12. An electrochemical cell (2) for a flow reactor (1), in particular a redox flow battery, comprising at least one cell frame (4) according to any one of claims 1 to 11.

13. The electrochemical cell according to claim 12, characterized in that At least one cell frame (4) according to any one of claims 1 to 11 is provided for each half cell (3).

14. An electrochemical flow reactor (1), in particular a redox flow battery, comprising at least one cell (2) according to claim 12 or 13.

15. The electrochemical flow reactor according to claim 14, characterized in that A battery of electrochemical cells (2) according to claim 12 or 13 is provided.

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