Separator plates for electrochemical systems

Abstract

The invention relates to a separator plate for an electrochemical system. The electrochemical system may in particular be a fuel cell system, an electrochemical compressor, an electrolyzer, or a redox flow battery. An electrochemical system comprising a plurality of such separator plates is also disclosed.

Description

TECHNICAL FIELD

[0001] The present invention relates to a separator plate for an electrochemical system. The electrochemical system can in particular be a fuel cell monoblock system, an electrochemical compressor, an electrolyzer, or a redox flow battery. An electrochemical system having a plurality of such separator plates is also disclosed. BACKGROUND

[0002] Known electrochemical systems of this type generally comprise electrochemical cells in a stack, which are separated from one another by separator plates. In the context of such a stack, the separator plates are also referred to as bipolar plates. The separator plates can serve, for example, for electrical contacting of the electrodes of individual electrochemical cells, such as fuel cell monoblocks, and / or for electrical connection of adjacent cells, a series connection of cells. Typically, the separator plates are formed from two individual plates, in particular bonded plates. The individual plates can be bonded together in a material- bonded manner, for example by one or more welded joints, in particular by one or more laser-welded joints.

[0003] The separator plates or individual plates can comprise or form respective structures which are configured, for example, to supply one or more media to an electrochemical cell arranged between adjacent separator plates and / or to remove reaction products. In particular, these structures can serve to guide a cooling fluid through a gap between the individual plates of a separator plate. The structures can comprise, for example, webs and channels. The media can thus be a fuel, such as hydrogen or methanol, a reaction gas, such as air or oxygen, or a coolant. In the context of the present disclosure, the terms media and fluid are used interchangeably.

[0004] Furthermore, the separator plates generally each have at least one through-opening through which a medium can be guided to or away from an electrochemical cell or membrane electrode assembly (MEA) arranged between adjacent separator plates of the stack.

[0005] From such a through-opening, the respective fluid is guided by means of the above-mentioned structures into a respective first distribution region and from there into a flow field opposite the active region of the cell or MEA. After flowing through the active region, the fluid is fed back via a second distribution region, also referred to as a collection region, to an outlet through-opening. An example thereof can be found in DE 20 2016 107 302 U1.

[0006] It is known that a first fluid, for example a fuel, can be guided on a first outer side of a separator plate, i.e. on an outer side of a first individual plate, and a second fluid, for example a reaction gas, can be guided on a second outer side of the separator plate facing away from the first outer side, i.e. on an outer side of a second individual plate. On the other hand, a cooling fluid is generally fed into an inner space bounded by the inner sides of the individual plates. The fluid-conducting structures on the respective outer sides of the individual plates form complementary structures on their inner sides for the conduction of the cooling fluid.

[0007] However, it has been found that the performance of such electrochemical systems can still be optimized. For example, the fluid guidance between the through-openings and the flow field still occupies a considerable proportion of the surface area on the respective side of the separator plate. This part of the surface is not available as active area of the battery cell and thus does not directly contribute to its performance. SUMMARY

[0008] It is therefore an object of the present application to improve the performance of electrochemical systems having a plurality of such separator plates.

[0009] This object is solved by the subject matter of claim 1. Advantageous further embodiments are given in the dependent claims as well as in the description and the figures.

[0010] Thus, a separator plate for an electrochemical system is proposed, comprising a first individual plate and a second individual plate which are opposite each other on the inside, wherein the separator plate has at least one first through-opening for a first fluid to pass through the separator plate and at least one further through-opening for a further fluid to pass through the separator plate,

[0011] wherein the first individual plate has on its outside at least one distribution area and a flow field, and the distribution area fluidically connects the first through-opening and the flow field to each other,

[0012] wherein the first individual plate further has on its outside at least one secondary channel which extends in at least some sections along a circumferential section of the further through-opening, wherein the circumferential section is directed away from the distribution area, wherein the secondary channel opens into a first fluid channel of the flow field, and the first through-opening is also fluidically connected to the flow field via the secondary channel.

[0013] According to the present application, the secondary channel utilizes surface areas of the separator plate for fluid supply to the flow field which are outside the conventional distribution area and also outside the distribution area according to the present application. Thereby, a previously unused fluid supply path for the flow field is provided. According to the present application, it is also recognized that at least sections of the secondary channel can extend into areas of the separator plate which can be used as such additional fluid supply paths without significantly affecting other structural features or functions of the separator plate. As explained below, some existing structural features, in particular the raised rim, can even be used for fluid guidance, which limits the amount of modification work compared to prior solutions.

[0014] Compared to prior solutions, the at least partial fluid supply to the flow field by the secondary channel enables a reduction of the number of channels and / or the area of the distribution area relative to the overall plate area. This enables an increase of the size of the flow field and thus an improved performance of the electrochemical system.

[0015] A further advantage is that the secondary channel can be flowed through at least in some sections without fluid accumulating and / or stagnating therein. This fluid can for example freeze. In the prior art solutions, however, there are indeed areas with such stagnant fluid accumulations.

[0016] For example, the prior art solutions have a gap between the convex edges arranged next to each other, which is also filled with fluid from the first through opening. This fluid can flow in, but cannot flow out, and thus stagnates in the gap. The secondary channel according to the application can also comprise such an intermediate gap, but provides an outlet option via the connection to the flow field, which enables the flow through the intermediate gap.

[0017] The through openings can be configured according to the prior art solutions. The first through opening and the further through opening and optionally the still further through opening can be positioned between the closest distribution area and the outer edge of the partition plate. The first through opening and the further through opening and optionally the still further through opening can be arranged in succession, preferably at a distance from each other, transverse to the main flow axis. In a known manner, the first through opening and the further through opening and optionally the still further through opening can be of different sizes, in particular with respect to their surface area, and / or their center of gravity can be positioned at different positions along the main flow axis.

[0018] According to a variant described in more detail below, there are three through openings, which are positioned between the distribution area and the outer edge of the partition plate in the manner described above. For example, viewed transverse to the main flow axis, the first through opening and the further through opening can accommodate the still further through opening therebetween.

[0019] The partition plate, in particular the first individual plate thereof, can have distribution areas on both sides of the flow field, whereby, when viewed along the main flow axis, between each distribution area and the outer edge of the partition plate closest to this distribution area, an arrangement of a through opening as disclosed herein together with a secondary channel as preferably disclosed herein can be provided.

[0020] The further through opening can in particular be a through opening for fluid guided on the outer side of the second individual plate. The second individual plate can also have at least one distribution area and a flow field on its outer side, and the distribution area connects the further through opening and the flow field in a fluid-conducting manner.

[0021] The first individual plate can form a cathode plate and / or can carry oxygen or air as a first fluid on its outer side. The second individual plate can form an anode plate and / or can carry hydrogen as a second fluid on its outer side. Alternatively, however, it is also possible to design the first individual plate as an anode plate and / or to carry hydrogen as a first fluid on its outer side. The second individual plate can then be designed as a cathode plate and / or can carry oxygen or air as a second fluid on its outer side.

[0022] The further through-opening can be a through-opening for a fluid guided between the inner sides of the individual plates opposite one another. This is typically a cooling fluid, wherein the inner sides opposite one another delimit a cooling fluid distribution structure.

[0023] The secondary channel can be connected in fluid-conducting fashion to the first through-opening, for example by means of a channel comprised or connected by a sealing rim surrounding the through-opening. In particular, the secondary channel cannot be connected in fluid-conducting fashion to the first through-opening via a detour of the distribution area. For example, fluid discharged from the first through-opening can branch off into the secondary channel and the distribution area.

[0024] If the flow direction is reversed, the first through-opening can be fed simultaneously from the secondary channel on the one hand and from the distribution area on the other hand. The volume proportion of the fluid into or out of the secondary channel can be smaller than the volume proportion of the corresponding distribution area. In particular, the volume fraction of the secondary channel can be less than 10%, in particular less than 8%, preferably less than 5% of the volume fraction carried by the distribution area.

[0025] The secondary channel can extend in a direction pointing away from the distribution area starting from its connection in fluid-conducting fashion with the first through-opening. In particular, the secondary channel can extend in the direction of the outer edge of the separation plate. Alternatively or additionally, the secondary channel can extend in the direction of the side of the first through-opening facing away from the distribution area.

[0026] The secondary channel can run at an angle, in particular substantially transversely, with respect to the main flow axis at least in some sections. It can extend along an optional further through-opening. In particular, it can run between a circumferential section of the further through-opening facing away from the distribution area and the outer edge of the separation plate closest to the further through-opening, and in the direction of the further through-opening. This indicates that the first through-opening and the further through-opening are preferably located close to different longitudinal sides of the separation plate. These longitudinal sides can extend along and in particular parallel to the main flow axis of the flow field.

[0027] The flow field can have a large number of fluid channels in a known manner. These fluid channels can run next to one another, in particular in straight lines and parallel to one another and / or in the same way in a wave shape next to one another. The fluid channels preferably run along a main flow axis of the flow field. This main flow axis can run parallel to a symmetry axis and / or longitudinal axis of the flow field, or form such an axis.

[0028] For example, the flow field can be characterized, for example, by the fact that all the webs and channels it comprises are straight and run parallel to one another and parallel to the main flow direction of the cooling fluid through the flow field. Alternatively, the webs and channels can also be wave-shaped and run next to one another in the same wave shape and along the main flow axis.

[0029] Additionally or alternatively, the flow field can be characterized by the fact that it is located within the MEA reinforcing rim and in particular is surrounded and / or framed by it at least in some sections. The MEA reinforcing rim is preferably, however, not opposite the flow field itself, but opposite the actual active area of the MEA, in particular in the form of its electrolyte membrane. By way of example, reference is made to DE 202020106459 U1 and in particular to Figure 3 B, which shows an MEA with a reinforcing rim that frames the active area of the MEA. It can be different, however, in terms of the more shallowly shaped region assigned to the flow field, in which the MEA reinforcing rim overlaps the GDL.

[0030] According to a further development, a first fluid channel of the flow field is fed with fluid only from the secondary channel and in particular not from a fluid channel of the distribution region. If the flow direction is reversed, this first fluid channel can feed fluid only to the secondary channel and not to any fluid channel of the distribution region. In terms of the structural aspect, this means that the first fluid channel of the flow field can only be connected in a fluid-conducting manner to / opens into the secondary channel and not simultaneously to a fluid channel of the distribution region. This allows the distribution region not to be designed for supplying fluid to the first channel, thus saving space.

[0031] In particular, the first fluid channel can be the outermost or almost outermost fluid channel of the flow field. In particular, one embodiment provides that no more than five further fluid channels of the flow field, in particular no more than three further fluid channels, are positioned between the first fluid channel of the flow field and the outer edge of the partition plate that is nearest to it. The corresponding nearest outer edge can be a longitudinal side of the partition plate that runs along or parallel to the main flow axis.

[0032] It is advantageous to position the first fluid channel close to the edge, since the first through-opening is usually positioned close to the corresponding opposite outer edge or to the corresponding opposite longitudinal side of the partition plate. The distance between the first fluid channel of the flow field and the first through-opening is correspondingly large. The fact that this first fluid channel is fed through the secondary channel without being fed through the distribution area means that a corresponding long channel length can be avoided in the distribution area. This allows a significant space saving to be achieved.

[0033] A further advantage arises from the fact that the fluidic connection of the secondary channel to the first fluid channel of the flow field can interrupt the cooling fluid supply to any further fluid channels positioned between the first fluid channel and the outer edge of the partition plate. This number should therefore be as small as possible. Even in this case, however, the material of the individual plate allows sufficient heat to be dissipated. According to an embodiment, it is also possible to supply cooling fluid in the region of these additional fluid channels via the circumferential bead.

[0034] A further development provides that the secondary channel extends along at least one third of the circumferential length of the further through-opening. In particular, the secondary channel can completely surround the further through-opening. This is particularly advantageous, since the secondary channel can be defined using the existing structural features surrounding the through-opening, see below.

[0035] According to a variant, the secondary channel extends at least in some sections between a circumferential section of the further through-opening and the outer edge of the partition plate closest to the further through-opening, wherein the circumferential drive is directed away from the distribution area. This outer edge can correspond to a lateral side of the partition plate running transversely to the main flow axis. The further through-opening is thus surrounded by the secondary channel at least in some sections from the perspective of the distribution area. In this case, too, the secondary channel can be delimited using existing structural features.

[0036] For example, a further aspect provides that the secondary channel is at least in some sections and at least partially delimited by the circumferential bead and / or a further bead of the partition plate. Any of these beads can also serve other functions and / or can also be present in existing partition plates without a secondary channel according to the application.

[0037] It can be understood that at least partial delimitation means that at least one side and / or at least one edge of the secondary channel is formed or defined by the respective bead. A further example of a bead of the partition plate that can provide such at least partial delimitation of the channel is a sealing bead that surrounds at least one through-opening.

[0038] According to a variant, the secondary channel is at least in some sections delimited by two beads that run next to one another, wherein each bead can form an edge of the secondary channel. This can be, for example, the circumferential bead and the sealing bead, or two sealing beads, whereby the sealing beads each run around a through-opening.

[0039] The circumferential bead can extend at least in some sections between the further through-opening and the at least one outer edge of the partition plate closest thereto. In particular, it can extend along a circumferential section of the further through-opening, wherein this circumferential section preferably faces away from the distribution region.

[0040] Generally, the circumferential bead can extend along the periphery and / or the outer edge of the partition plate, in particular in a closed circumferential form.

[0041] Additionally or alternatively, the secondary channel can be at least in some sections and at least partially delimited by at least one weld seam. For example, the secondary channel can at least in some sections run on the plate surface, the weld seam that joins the two individual plates of the partition plate extending on the plate surface.

[0042] In a further development, the secondary channel also has at least one section that extends along a circumferential section of the further through-opening, wherein the circumferential section faces the distribution region, wherein at least one fluid channel opening of the distribution region opens into this section of the secondary channel and / or is connected in a fluid-conducting manner to this section. In this case, the secondary channel can be connected in a fluid-conducting manner to the first through-opening via the distribution region in addition to the opening into the channel through the sealing bead that surrounds the first through-opening, as described above. This variant also enables a reduction in the size of the distribution region, since the channel length required in the distribution region for the connection to the above-mentioned section of the secondary channel is shorter than the channel length required for the first fluid channel that feeds the flow field through the distribution region. The latter takes place by means of the secondary channel.

[0043] As indicated above, a preferred variant provides that the first through-opening is positioned adjacent to a first outer edge of the partition plate and the further through-opening is positioned adjacent to a second outer edge of the partition plate, which second outer edge is opposite the first outer edge. The first outer edge and the second outer edge can each correspond to a longitudinal side of the above-described type and / or extend along the main flow axis. Thus, the first outer edge and the second outer edge can be arranged opposite one another along an axis that is perpendicular to the main flow axis of the flow field.

[0044] According to a further embodiment, the partition plate has a second through-opening and a third through-opening as further through-openings, wherein the third through-opening is positioned according to the further through-opening of the aforementioned aspects, i.e. close to a second outer edge of the partition plate that is opposite the first outer edge. The second through-opening is preferably arranged between the first through-opening and the third through-opening, in particular perpendicular to the main flow axis.

[0045] In this context, it can also be provided that the secondary channel extends at least in some sections along a circumferential section of each of the second through-opening and the third through-opening, wherein the circumferential section faces away from the distribution region.

[0046] In a further embodiment, the distribution area has at least one, preferably a plurality of channels which are bounded on both sides by webs. At least one channel and preferably all or at least a majority of the channels have a length which is at least 5 times, preferably at least 10 times, in particular at least 20 times the width of the respective channel, the width being measured between the height maxima of the webs bounding the channel. The channels can thus be elongated fluid-conducting structures.

[0047] When the term flow field is used herein, this term can refer to the actual flow field as well as to an overlap area which closes the flow field in the direction of the distribution area. In this overlap area, the cooling fluid channels can be formed less high compared to the actual flow field, thereby leaving enough space for the overlap of the GDL and the MEA reinforcement edge which will be explained below.

[0048] The height and the height maximum of the web can be measured orthogonally to the surface plane of the separator plate, in particular of the first individual plate. In a known manner, the flat surface plane of the respective individual plate can be defined, for example, by the edges of the individual plate or by the flat areas of the individual plate which are not deformed due to the embossing or deep-drawing process to form the web channel structure or the embossed edge as described herein. In one aspect, the surface plane can run in the neutral fiber of the respective section of the plate; in another aspect, the surface of the relevant section of the plate can also be considered as the surface plane. However, when using the latter approach, it has to be ensured that only the material thickness of the one separator plate of the two plates considered is taken into account or similar factors.

[0049] The present application also relates to an electrochemical system comprising a plurality of separator plates according to any aspect described herein. BRIEF DESCRIPTION OF DRAWINGS

[0050] The present application is explained below with reference to the accompanying schematic drawings. In all drawings, like reference signs can be used to refer to similar or functionally similar features.

[0051] Figure 1 A perspective view of an electrochemical system having a large number of stacked separator plates and membrane electrode units arranged therebetween is shown.

[0052] Figure 2 A perspective view of two separator plates of a system similar to Figure 1 , wherein a membrane electrode assembly (MEA) is arranged between the separator plates.

[0053] Figure 3 is a schematic simplified representation of the fluid guidance within a separator plate according to an example of the prior art.

[0054] Figure 4 is another schematic simplified representation of the fluid flow within a separator plate according to an example of the prior art.

[0055] Figure 5 is a schematic simplified representation of fluid guiding within a separator plate according to a first embodiment of the present application.

[0056] Figure 6 is a schematic simplified representation of fluid guiding within a separator plate according to a second embodiment of the present application. DETAILED DESCRIPTION

[0057] Figure 1 An electrochemical system 1 of the type presented here is shown, which has a plurality of identical metal separator plates 2 (or bipolar plates). These metal separator plates are arranged in a stack 6 and are stacked along a z-direction 7. The separator plates 2 of the stack 6 are clamped between two end plates 3, 4. The z-direction 7 is also referred to as stack direction. In the present example, the system 1 is a fuel cell monoblock stack. Each two adjacent separator plates 2 of the stack 6 enclose an electrochemical cell monoblock therebetween, which is for example used to convert chemical energy into electrical energy. To form the electrochemical cell monoblocks of the system 1, membrane electrode units (MEA) 10 are arranged between adjacent separator plates 2 of the stack 6 (see below Figure 2 ). The MEAs each contain at least one membrane, for example an electrolyte membrane. In addition, gas diffusion layers (GDL) can be arranged on one or both surfaces of the MEA.

[0058] In alternative embodiments, the system 1 can likewise be designed as an electrolyzer, a compressor or a redox flow battery. In these electrochemical systems, separator plates can likewise be used. The structure of these separator plates can correspond to the structure of the separator plates 2 described in detail herein, although in an electrolyzer, electrochemical compressor or redox flow battery, the media fed onto and / or through the separator plates can differ from the media used for a fuel cell monoblock system.

[0059] The z-axis 7 forms, together with the x-axis 8 and the y-axis 9, a right-handed Cartesian coordinate system. The separator plates 2 each define a plate plane, whereby the plate planes of the separator plates 2 are each aligned parallel to the x-y plane and thus perpendicular to the stack direction (z-axis 7). The end plate 4 comprises a plurality of media connections 5 via which media can be supplied to the system 1 and via which media can be discharged from the system 1. These media that can be supplied to and discharged from the system 1 can for example include a fuel such as molecular hydrogen or methanol, a reaction gas such as air or oxygen, a reaction product such as water vapor or depleted fuel, or a cooling fluid such as water and / or ethylene glycol.

[0060] Figure 2 A perspective view of two adjacent separator plates 2 or bipolar plates is shown, which can be Figure 1The separator plate 2 corresponds to one example of the prior art. However, the properties and features explained below in relation thereto can also be applied or be envisaged for the separator plate 2 of the application disclosed herein, unless otherwise stated or apparent.

[0061] Figure 2 It is also shown a known membrane electrode assembly (MEA) 10 arranged between these adjacent separator plates 2, wherein Figure 2 The MEA 10 is largely obscured by the separator plate 2 facing the observer in. The separator plate 2 is formed by two separate plates 2a, 2b joined with a material bond, wherein in Figure 2 only the separate plate 2a facing the observer is visible in, which obscures the other separate plate 2b. The separate plates 2a, 2b can each be made of a metal sheet, for example of a stainless steel sheet. For example, the separate plates 2a, 2b can be welded together, for example by laser welding, or only connected when stacked. In particular, Figure 2 The design of the fluid guiding structures on the outer side of the separate plate 2a facing the observer in can be different from the structures according to the application in the other figures below.

[0062] The separate plates 2a, 2b have through openings which are aligned with each other, forming through openings 11a-11c of the separator plate 2. When a plurality of separator plates 2 are stacked, the through openings 11a to 11c form lines extending through the stack 6 along the stacking direction 7 (see Figure 1 ). Typically, each line formed by the through openings 11a to 11c is in fluid communication with one of the ports 5 in the end plate 4 of the system 1. For example, a cooling fluid can be introduced into or discharged from the stack 6 via a fluid line formed by the through openings 11a. On the other hand, the lines formed by the through openings 11b, 11c can be designed to supply fuel and reaction gases to the electrochemical cells of a fuel cell monoblock stack of the system 1 and can also be designed to discharge reaction products from the stack 6.

[0063] In order to seal the through openings 11a to 11c from the interior of the stack 6 and from the surroundings, the separate plate 2a facing the observer has a sealing arrangement in the form of sealing beads 12a to 12c. These sealing beads are each arranged around and completely surround the through openings 11a to 11c. The second separate plate 2b also has corresponding sealing beads 12a to 12c to seal the through openings 11a to 11c on the rear side of the separator plate 2 facing away from the observer in Figure 2 Alternative sealing systems, for example elastomer seals, can also be used.

[0064] At the abutment of the electrochemically active area 18 of the MEA, the observer- facing individual plate 2a has on its observer-facing outer side a flow field 17a with structures for guiding a reaction medium along the outer side of the individual plate 2a. These structures are shown in Figure 2 Fig. 3 in the form of a multitude of webs and channels running between and bounded by the webs. On the outer side of the observer-facing separator plate 2, the observer-facing individual plate 2a also has two distribution areas 20a. The distribution areas 20a each comprise structures configured to distribute the medium introduced into one of the distribution areas 20a onto the active area 18 by means of the flow field 17a from a first one of the two through-openings 1 1 b, or configured to collect or concentrate the medium flowing from the active area 18 or from the flow field 17a to a second one of the through-openings 1 1 b. In the latter case, the collecting distribution area 20a can also be referred to as a collecting area. The fluid- guiding structures of the distribution areas 20a are also shown in Figure 2 Fig. 3 by webs and channels running between and bounded by the webs.

[0065] Without being shown separately in Figure 2 Fig. 3, the cooling fluid distribution structure 19 formed and / or enclosed between the individual plates 2a, 2b also has distribution areas 20c which overlap with the distribution areas 20a, 20b of the individual plates 2a, 2b. This cooling fluid distribution structure 19 is fluidically connected to a flow field 17c which overlaps with and / or is enclosed between the flow fields 17a, 17b of the outer sides of the individual plates 2a, 2b, or which comprises this flow field 17c. The web-channel structure on the outer sides of the individual plates 2a, 2b forms a complementary-shaped web-channel structure on the respective inner side and thus a complementary-shaped web-channel structure of the cooling fluid distribution structure 19.

[0066] Via the channels 13b in the sealing rims 12b, via the distribution structures of the distribution areas 20, and via the flow fields 17a of the observer-facing individual plates 2a of the Figure 2 two through-openings 1 1 b and / or the lines formed by the through-openings 1 1 b of the plate stack of the system 1 are fluidically connected to each other. This individual plate 2a is a second individual plate 2a in the sense of the present disclosure. The fluid guided along the outer side of this individual plate 2a is preferably hydrogen, and thus the through-openings 1 1 b are preferably hydrogen through-openings 1 1 b. This is evident in particular from the smallest cross-section of the hydrogen through-openings 1 1 b compared to the other through-openings 1 1 a, 1 1 c.

[0067] In a similar manner, two through-openings 1 1 c and / or the lines formed by the through-openings 1 1 c through the plate stack of the system 1 are fluidically connected to each other via the corresponding rim channels 13c, via the corresponding distribution structures, and via the flow fields 17b of the observer-facing individual plates 2b facing away from the observer. Figure 2The corresponding flow fields on the outer sides of the observers are fluidically connected to each other in a similar manner. This single plate 2b is a second single plate 2b in the sense of the present disclosure. The fluid guided along the outer sides of this single plate 2b is preferably air or oxygen, thus the through-openings 11c are preferably air or oxygen through-openings 11c. This can in particular be derived from the larger cross-section of the air or oxygen through-openings 11c compared to the other through-openings 11a, 11b.

[0068] The through-openings 11a and / or the lines formed by the through-openings 11a, which pass through the stack of plates of the system 1, are on the other hand each fluidically connected to each other via a chamber enclosed or wrapped by the single plates 2a, 2b, which forms a cooling fluid distribution structure 19. This is for example achieved by the channels 13a. This cavity or cooling fluid distribution structure 19 serves for guiding a cooling fluid through the separator plates 2, in particular for cooling the electrochemically active areas 18 of the MEA. Thus, the through-openings 11a are cooling fluid through-openings, which is in particular evident from their average cross-sectional dimension compared to the other through-openings 11b, 11c.

[0069] Figure 3 A partial area of the separator plate 2 from Figure 2 is shown, more precisely a partial area of its first single plate 2b is shown, which is masked in Figure 2 . This partial area corresponds to an end area comprising three through-openings 11a to 11c. The positioning of these through-openings 11a to 11c can be clearly seen, which is rotated by 90° compared to Figure 2 .

[0070] All of the following Figures 3 to 6 relate to such sub-areas. However, it is to be understood that the opposite end areas, respectively comprising three further through-openings 11a to 11c, can also be configured in the same manner and have similar fluid guidance, as shown in the respective figures. There, however, the flow direction is generally reversed (see Figure 2 for an explanation).

[0071] Figure 3 The view of Figure 3 is particularly schematic, showing the fluid guidance by superimposing the distribution areas 20a, 20b. Thus, this view corresponds to an orthogonal projection of these fluid guidances onto a common plane or a view through the separator plate 2. The matters explained below with respect to may also be provided in the solution disclosed here, unless indicated otherwise or apparent.

[0072] Figure 3The three through openings 11a to 11c and their channels 13a to 13c passing through the circumferential sealing flanges 12a to 12c are shown again; the sealing flanges 12a to 12c are not shown separately. The fluid guided by the through openings 11a to 11c into the structure of the partition plate 2 is indicated by arrows of different types.

[0073] Furthermore, the differently arranged shaded lines indicate the extensions of distribution regions 20a and 20b formed on the outer sides of the individual plates 2a and 2b. Distribution regions 20a and 20b connect the shown through openings 11c and 11b to their respective flow fields 17a and 17b via fluid conduction. Cooling fluid from the through opening 11a flows along the inner sides of two of these distribution regions 20a and 20b in the direction of the flow field 17c used for cooling fluid. This flow field 17c surrounds the flow fields 17a and 17b; in other words, it is surrounded by their inner sides.

[0074] It can be seen that the assigned regions 20a and 20b overlap each other in the cross-shaded area.

[0075] exist Figure 3 In the flow fields 17a to 17c, the corresponding fluids are guided vertically, and for example, in a straight line along the main flow axis S. The flow fields 17a to 17c along... Figure 3 Each of the widths, moving from left to right, has a series of elongated fluid channels, not shown individually.

[0076] The through openings 11a to 11c are distributed laterally along the main flow axis S. As an example, they and / or their respective centers of gravity (not shown separately) are offset from each other along the main flow axis S.

[0077] The through opening 11c forms the first through opening in the sense of this disclosure. The through opening 11a forms the second through opening in the sense of this disclosure. The through opening 11b forms the third through opening in the sense of this disclosure.

[0078] As can be seen, the first through opening 11c is located near the first outer edge 30 of the partition plate 2, which extends along the main flow axis S and thus corresponds to the longitudinal side of the partition plate 2. In particular, when viewed along an axis (not shown) that travels transversely to the main flow axis S, the second outer edge 32 of the partition plate 2 is opposite to this. Therefore, this second outer edge 32 also corresponds to the longitudinal side of the partition plate 2.

[0079] The third outer edge 34 of the partition plate 2 is also shown, which travels transversely to the main flow axis S and thus corresponds to the transverse side. A fourth outer edge forming another transverse side is shown in... Figure 3 Not shown in the image.

[0080] If the fluid to be discharged from the first through opening 11c is to reach a fluid channel in the flow field 17b close to the second outer edge 32 and thus far away from the through opening 11c, a correspondingly long fluid channel has to be formed in the distribution area 20b. This relatively long fluid channel requires a relatively large space on the outer side of the second individual plate 2b.

[0081] This relationship is shown by Figure 4 Further explanation, Figure 4 A more detailed view of the outer side of the second individual plate 2b of the partition plate 2 according to the prior art example is shown. In this case, the individual fluid channels 36b of the distribution area 20b are indicated with white arrows, each fluid channel 36b being delimited by two adjacent webs 38b. Figure 4 Only selected fluid channels 36b and webs 38b are labeled with the respective reference numerals in the Figure 4 It can be seen that the length of the fluid channels 36b increases if the fluid channels 36b are required to feed fluid to the fluid channels 40b of the flow field 17b at an increasingly greater distance from the through opening 11c. Thus, in

[0082] Figure 4 Further areas 42 of the second individual plate 2b outside the distribution area 20b are also shown, which areas absorb fluid from the through opening 11c. These areas 42, or rather the fluid contained therein, are Figure 4 Selected areas of these areas 42 are labeled with the respective reference numerals in the

[0083] The areas 42 are delimited by the circumferential peripheral rim 44 and the sealing rim 12a to 12c surrounding the through openings 11a to 11c. In particular, the areas 42 completely surround the first through opening 11c and the third through opening 11b, follow the circumferential portion of the further through opening 11a facing away from the distribution area 20b, and in each case extend in the intermediate space between two of the through openings 11a, 11b, 11c.

[0084] Under the first through opening 11c is an area 42, shown with a white dashed line, to which the channel 13c leads. In addition, this area is connected in a fluid-conducting manner to the fluid channels 36b of the distribution area 20b. This area 42 extends channel-like along the outer peripheral section of the first through opening 11a facing the distribution area 20b and is thus angled with respect to the respective longitudinal axis of the fluid channels 36b of the distribution area 20b.

[0085] Fluid is distributed from this area 42 into other areas 42. However, fluid resides in these areas 42 and does not flow through these areas 42, in particular not continuously. It thus does not contribute to the performance of the electrochemical system 1 comprising the separator plate 2. The areas 42 thus form channels which do not directly contribute to the fluid supply of the flow field 17b. They also have no other separate function, at least not in terms of fluid guidance.

[0086] Figure 5 is a highly simplified schematic view of the first embodiment of the present application. This view corresponds to a view through the separator plate 2 as in Figure 3 the case. The majority of the separator plate 2 is constructed analogously to the example in Figures 2 to 4 , however, with the exception of the fluid guidance, in particular on the outside of the first separate plate 2b shown below. Due to the overlap, Figure 5 and the following Figure 6 mainly use the same reference signs as the preceding figures.

[0087] Figure 5 is also analogous to Figure 3 , as the fluid guidance is superimposed on the distribution areas 20a, 20b. This view thus again corresponds to an orthogonal projection of these fluid guidances onto a common plane or a view through the separator plate 2.

[0088] Figure 5 shows that at least the first through-opening 11c and the third through-opening 11b are completely surrounded by the secondary channel 50. Analogous to Figure 4 , the secondary channel 50 supplies fluid from the channel 13c over a section which runs between the first through-opening 11c and the distribution area 20b and feeds the distribution area 20b itself with fluid.

[0089] The secondary channel 50 runs along the second through-opening 11a transversely to the main flow axis S. The secondary channel 50 extends along a circumferential section of the second through-opening 11a which faces away from the distribution area 20b. As explained below with reference to Figure 6 , the secondary channel 50 can in turn be at least sectionally delimited by a ledge which is arranged in any way, in particular runs between both. All illustrated sections of the secondary channel 50 merge into one another without interruption and in a fluid-conducting manner.

[0090] In contrast to Figure 3 , only one section line is shown in Figure 5 which fills the entire surface of the distribution area 20b. However, the flow arrows of the fluid from the third through-opening 11b also show an extension of the further distribution area 20a.

[0091] The fluid channel 36b of the distribution area 20b, which is preferably the uppermost one or the outermost one viewed along the main flow axis S, opens to the secondary channel 50 by means of a connecting section 51. In particular, the connecting section 51 opens to the secondary channel 50 along a section of the third through-opening 1 1 b and faces the distribution area 20b.

[0092] The secondary channel 50 and the first through-opening 1 1 c are thus also connected to one another in a fluid-conducting manner via the distribution area 20b. Optionally, several fluid channels 36b of the distribution area 20b can also open to the secondary channel 50.

[0093] The connecting section 51 can be assigned to the distribution area 20b as a fluid channel extension. Alternatively, it can be understood as a section of the secondary channel 50. There can also be variants without an independent connecting section 51, for example if the fluid channels 36b of the distribution area 20b open to the secondary channel 50 substantially continuously and without a directional change.

[0094] At least some of the fluid that enters the distribution area 20b from the through-opening 1 1 c via the channel 13c thus returns from the distribution area 20 to the secondary channel 50. This fluid can fill all sections of the secondary channel 50 and in particular flow through at least some of the sections. The latter is facilitated by the fact that the secondary channel 50 is connected to an exemplary outermost fluid channel 40b of the flow field 17b in a fluid-conducting manner. This means that at least some of the incoming fluid exits from the secondary channel 50 and flows into or through the flow field 17b.

[0095] This fluid channel 40b is fed only by the secondary channel 50 and is connected only in a fluid-conducting manner to the secondary channel 50. On the other hand, there is no direct fluid-conducting connection between this fluid channel 40b and one of the fluid channels 36b of the distribution area 20b, i.e. there is no fluid channel 36b that opens to the fluid channel 40b of the flow field 17b fed by the secondary channel 50.

[0096] Finally, Figure 5 It is also shown that the cooling fluid from the second through-opening 1 1 a is guided only along the inner side of the distribution area 20b of the first individual plate 2b. The reason for this is that the connecting section 51 spans the potential flow path of the cooling fluid in the direction of the third through-opening 1 1 b. There is thus not enough flow cross section in the interior between the individual plates 2a, 2b by means of which the cooling fluid can reach the inner side of the distribution area 20a, i.e. the coolant distribution area 20c that is connected in a fluid-conducting manner to the third through-opening 1 1 b. Rather, the cooling fluid reaches this area only via the inner side of the distribution area 20b. It flows along this inner side into the areas of the distribution areas 20a, 20b that face one another (see the cross-hatched areas in Figure 3 ).

[0097] However, it has been shown that even if the cooling fluid only flows along the inner side of one of the distribution areas 20a, 20b, a sufficient cooling effect can be achieved.

[0098] Figure 6 Another embodiment of the application is shown in a view similar to Figure 4 Another embodiment of the application is shown in a view similar to Figure 5 but not additionally fed by the fluid channels 36b of the distribution area 20b.

[0099] It is shown that in the vicinity of the longitudinal side of the separation plate 2 remote from the first through opening 11c, the secondary channel 50 extends in the direction of the flow field 17b and opens there to one of the fluid channels 40b of this flow field 17b. As in Figure 5 this fluid channel 40b is only directly connected to the secondary channel 50 and does not open to any fluid channel 36b of the distribution area 20b.

[0100] Even if this is not clearly visible from the schematic views of the figures of the present description, this can for example result in a reduced number of fluid channels in the distribution area 20b and / or a reduced size of the distribution area 20b along the main flow axis S compared to Figure 4

[0101] Figure 6 It is also schematically indicated that the width extension of the flow field 17b by the blocks 100, 102 according to another alternative embodiment. It is shown that the fluid channels 40b do not necessarily have to be only the outermost fluid channels 40b, but further fluid channels 40b can also extend between their nearest outer edge or nearest longitudinal side of the separation plate 2. This is shown in Figure 6 by the smaller blocks 102.

[0102] Inside the large blocks 100, cooling can also reliably be provided by the internal cooling fluid distribution structure 19. In the case of the blocks 102, this is not necessarily the case due to their limited size. However, if the flow field on at least the second individual plate 2a outer side is fully connected to and supplied by the distribution area 20a there, i.e. the secondary channel 50 does not similarly merge into one of the fluid channels 40a of the flow field 17a, this can also be achieved at least in the overlap region.​

Claims

1. Separator plate (2) for an electrochemical system (1), comprising a first individual plate (2a) and a second individual plate (2b), the inner sides of the first individual plate (2a) and the second individual plate (2b) facing each other, wherein the separator plate (2) having at least one first through-opening (11c) for passing a first fluid through the separator plate (2) and at least one further through-opening (11b) for passing a further fluid through the separator plate (2), wherein the first individual plate (2b) has at least one distribution area (20b) and a flow field (17b) on its outer side, and the distribution area (20b) fluidically connects the first through-opening (11c) and the flow field (17b) to each other, wherein the first individual plate (2b) further has at least one secondary channel (50) on its outer side, the secondary channel (50) extending in at least some sections along a circumferential section of the further through-opening (11b), wherein the circumferential section faces away from the distribution area (20b), wherein the secondary channel (50) opens into a first fluid channel (40b) of the flow field (17b), and the first through-opening (11c) is also fluidically connected to the flow field (17b) via the secondary channel (50).

2. Separator plate (2) according to claim 1, characterized in that the first fluid channel (40b) of the flow field (17b) is fed with fluid only from the secondary channel (50), and in particular not from a fluid channel (36b) of the distribution area (20b).

3. Separator plate (2) according to claim 1 or 2, characterized in that no more than five further fluid channels (40b) of the flow field (17b), in particular no more than three further fluid channels (40b), are positioned between the first fluid channel (40b) of the flow field (17b) and the outer edge (32) of the separator plate (2b) most adjacent thereto.

4. Separator plate (2) according to any of the preceding claims, characterized in that the secondary channel (50) extends along at least one third of the circumferential length of the further through-opening (11b), in particular wherein the secondary channel (50) completely surrounds the further through-opening (11b).

5. Separator plate (2) according to any of the preceding claims, characterized in that the secondary channel (50) is at least in some sections and at least partially bounded by a peripheral ledge (44) and / or another ledge (12a-12c) of the separator plate (2), wherein the peripheral ledge (44) extends in at least some sections between the further through-opening (11a, 11b) and at least one outer edge of the separator plate (2) most adjacent thereto.

6. Separator plate (2) according to any of the preceding claims, characterized in that The secondary channel (50) further comprises at least one section extending along a circumferential section of the further through opening (11a, 11b), wherein the circumferential section faces the distribution area (20b), wherein at least one fluid channel (36b) of the distribution area (20b) opens to and / or is fluidically connected to this section of the secondary channel (50).

7. The partition plate (2) according to any one of the preceding claims, characterized in that The first through opening (11c) is positioned adjacent to a first outer edge (30) of the partition plate (2), and the further through openings (11a, 11b) are positioned adjacent to a second outer edge (32) of the partition plate (2), the second outer edge (32) being opposite to the first outer edge (30).

8. The partition plate (2) according to any one of the preceding claims, characterized in that having a second through opening (11a) and a third through opening (11b) as further through openings, wherein the third through opening (11b) is positioned according to the further through opening of claim 7, and the second through opening (11a) is arranged between the first through opening (11c) and the third through opening (11b).

9. The partition plate (2) according to claim 8, characterized in that The secondary channel (50) extends at least in sections along a circumferential section of each of the second through opening (11a) and the third through opening (11b), wherein each circumferential section faces away from the distribution area (20b).

10. The partition plate (2) according to any one of the preceding claims, characterized in that The distribution area (20b) has at least one channel (36b) which is bounded on both sides by a web (38b), and preferably a plurality of channels (36b), which are each bounded on both sides by a web (38b), wherein the at least one channel (36b) has a length which is at least 5 times, preferably at least 10 times, in particular at least 20 times, as great as a width of the channel (36b), the width being measured between the height maxima of the webs (38b) which bound the channel (36b).

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