Bipolar plates, indwelling samples for bipolar plates, systems, and methods for producing and testing bipolar plates

Abstract

The invention relates to a bipolar plate (2) for an electrochemical system (1), the bipolar plate (2) comprising two separators (2a, 2b) connected to each other, at least one of the separators (2a, 2b) having a plate body (21) and at least one tab (30, 31, 32, 39), the at least one tab (30, 31, 32, 39) being formed in one piece with the plate body (21) and being detachable from the plate body (21) via a predetermined breaking point (33). The invention also relates to a sample for a bipolar plate or flow plate, to a flow plate, to a system, and to a method for producing and testing a bipolar plate or flow plate.

Description

Technical Field

[0001] This document relates to a bipolar plate for an electrochemical system, to a retained sample for a bipolar plate or flow plate, to a system comprising a retained sample and a bipolar plate or flow plate, to a flow plate, to a method for producing a bipolar plate or flow plate, and to a method for testing a retained sample of a bipolar plate or flow plate. The electrochemical system may be, for example, a fuel cell system, an electrochemical compressor, a redox flow battery, a humidifier for an electrochemical system, or an electrolyzer. Background Technology

[0002] Known electrochemical systems typically comprise stacked electrochemical cells, each separated from the others by separators. Such bipolar plates can be used, for example, to indirectly electrically contact the electrodes of a single electrochemical cell (e.g., a fuel cell) and / or electrically connect adjacent cells (cells in series). Bipolar plates are typically formed from two separate separators bonded together; these can also be referred to as separators. The separators of a bipolar plate can be bonded together by material bonding, for example, through one or more weld joints, particularly through one or more laser-welded joints.

[0003] Bipolar plates and / or separators may each have or form structures such that, for example, they are configured to provide one or more media to an electrochemical cell defined by adjacent bipolar plates, and / or remove reaction products therefrom. The media may be a fuel (e.g., hydrogen or methanol) or a reactant gas (e.g., air or oxygen). Furthermore, bipolar plates and / or separators may have structures for guiding cooling media through the bipolar plates, particularly through cavities enclosed by the separators of the bipolar plates. Additionally, bipolar plates may be configured to transfer waste heat generated when electrical and / or chemical energy is converted in the electrochemical cell, and also to seal various media channels and cooling channels relative to each other and / or relative to the outside.

[0004] Furthermore, each bipolar plate typically has multiple through-holes. Through these through-holes, the dielectric and / or reaction products can be conducted into the electrochemical cell defined by the stacked adjacent bipolar plates or into the cavity formed by the separators of the bipolar plates, or they can be conducted to the outside of the cell or the cavity. Each electrochemical cell also typically includes one or more membrane electrode assemblies (MEAs). MEAs may have one or more gas diffusion layers, which are typically oriented toward the bipolar plates and formed, for example, as a metal felt or carbon felt.

[0005] The separators and flow plates can be formed from freely shaped metal sheets, such as embossed or deep-drawn stainless steel sheets. These sheets are typically about 60 μm to a maximum of 150 μm thick. Because these are very delicate yet relatively large components, bipolar plates or separators can be difficult to manipulate in certain situations. On the one hand, due to their relatively small thickness, separators or bipolar plates can be sensitive to mechanical deformation. Furthermore, contamination of uncoated or coated areas must be avoided. However, due to the diverse nature of their surfaces for many functions, separators or bipolar plates should generally only be manipulated in their largely unstructured edge areas. In practice, this is found to be not always possible, or not always done, due to the sharp edges. Therefore, people or machines that need to handle these separators or bipolar plates are not always able to transport, position, grasp, or manipulate them in a proper manner. As a result, the partitions or bipolar plates are often contaminated, for example by human fingerprints or residue from suction-lifting tools such as automated gripping systems, and / or by deformation of the partitions or bipolar plates or inaccurate positioning of the partitions or bipolar plates.

[0006] Another issue lies in quality assurance for partitions, flow plates, or bipolar plates, because traditional measurement methods can only be used on finished components in a limited range or in a destructive manner.

[0007] In addition, it is expected that, for example, in the event of a complaint, traceability of the finished bipolar plates or flow plates can be established. Summary of the Invention

[0008] The purpose of this invention is to solve at least one or more of the problems mentioned above.

[0009] This objective is achieved by means and methods according to the appended independent claims. Embodiments and advantageous developments of the invention are disclosed in the dependent claims and the following description.

[0010] According to one aspect, a bipolar plate for an electrochemical system is provided. The bipolar plate includes two separators connected to each other, at least one of the separators having a plate body and at least one tab, the at least one tab being formed as a single piece with the plate body and separable from the plate body via a predetermined break point.

[0011] A tab can perform one or more functions. In particular, a tab can simplify and / or enable the transport, traceability, and / or process monitoring of bipolar plates. To this end, the tab may specifically have functional elements designed for this purpose. The various aspects of the tab and / or these functional elements will be described in more detail in the following description.

[0012] Tabs are typically configured for transporting, positioning, holding, and / or gripping bipolar plates or bipolar plates. As a result, the bipolar plate or bipolar plate can be manipulated at the tab without the plate body being contaminated by fingerprints or residues from lifting tools, such as suction lifting tools from automated gripping systems, or mechanically deformed. Predetermined break points are typically configured so that they do not break or plastically deform under the weight of the bipolar plate or bipolar plate. On the other hand, deformation of the tab is permissible, particularly during separation. The tab may have a holding area intended to be held by a person or machine and is preferably sized accordingly. The holding area may, for example, be a flat surface portion formed on the tab. For positioning the bipolar plate or bipolar plate, it is advantageous that the tab has a locating opening for receiving a centering pin. If the tab is only used for transporting, positioning, holding, and / or gripping the bipolar plate and / or bipolar plate, separation of the tab can be performed at any suitable point in time during or at the end of the production process, or not until during or after installation.

[0013] At least one tab may be disposed at various suitable points on the bipolar plate. The tab or tab plane typically extends in or parallel to the plate surface defined by the plate body. Alternatively, the tab may be oriented at least partially at an angle to the plate plane. In one embodiment, the tab is arranged on the outer edge of the plate body. The tab may be configured, for example, as a hanger projecting laterally from the plate body. The bipolar plate may have at least one through opening serving as a fluid passage. The tab may be arranged, for example, on the inner edge of such a through opening. The common edge of the tab and the edge of the plate body preferably occupies only a portion of the length of the edge of the plate body in question, such as at most one-third or half the length of the inner edge of the through opening, or at most one-twentieth the length of the circumferential outer edge of the plate body, or at most one-eighth the length of an outer edge of the plate body, i.e., a side edge.

[0014] The predetermined break point is typically designed to allow for defined separation of the tab along that break point. Defined separation largely prevents damage to the bipolar plate and / or the tab after separation. It can be provided that a reinforcing structure, extending at least partially along the predetermined break point, is arranged along the predetermined break point in a defined manner for separating the tab, preferably on at least one side of the predetermined break point, and preferably on both sides of the predetermined break point. Furthermore, or alternatively, the tab may have at least one further reinforcing structure for reinforcing the tab. In this case, the corresponding reinforcing structure can be configured as a convex structure, a convex edge, or a group of raised protrusions. A convex edge can be configured, for example, as a semi-convex edge or a full convex edge. Additionally, domes or small blocks can be provided as raised protrusion structures, for example, arranged in at least one row.

[0015] The predetermined fracture point may, for example, include at least one notch and / or at least one perforation. A plurality of spaced notches and / or perforations arranged in a row may also be provided. In the context of this document, a perforation is configured as a through opening, while a notch is configured as a partially penetrating weakened portion of the material. The predetermined fracture point is typically configured as a predetermined fracture line and may extend, for example, in an arc or a straight line along a longitudinal direction, or may be formed by an arcuate portion and / or a straight portion arranged adjacent to each other in a row.

[0016] Optionally, the tab has a first code associated with a corresponding separator and / or bipolar plate. In this case, the first code of the tab can be used as an identification feature of the corresponding bipolar plate. Typically, the separator and / or bipolar plate has a second code corresponding to the first code on the tab. Thus, the corresponding codes (i.e., the first code and / or the second code) enable traceability of the bipolar plate, particularly after its production. In some embodiments, the corresponding codes include inscriptions and / or patterns. The pattern can then be constructed as a barcode, a 2D code such as a data matrix code or a QR code, a color pattern, a stamped pattern, and / or an embossed pattern. The corresponding codes can also include chips, such as RFID chips. For example, batches of the plate material used can be tracked in this way.

[0017] Optionally, the tab may have at least one process monitoring area. This at least one process monitoring area may be arranged on one side, particularly on a flat surface of the tab, or on both sides of the tab. Components (elements) that can be inspected during and / or after bipolar plate production and thus can monitor certain process parameters may be included in or applied to the process monitoring area of ​​the tab. Components included in or applied to the process monitoring area are typically present in the same, representative, or at least similar form on the separator or bipolar plate body, so test results from the process monitoring area can be transferred to the separator or bipolar plate; this is particularly true because the tab and the rest of the plate body are made from the same material from the same batch. For example, the tab can be tested directly after the production of the relevant bipolar plate and before it is installed in the electrochemical system. This prevents low-quality bipolar plates from being installed in the system. The process monitoring area may, for example, have a coating, surface treatment, and / or structure.

[0018] At least one process monitoring area may have a coating, preferably a sealing coating, adhesive coating, conductive coating, or anti-corrosion coating. This coating may include coatings applied by screen printing, coatings applied by a knife, spray coatings, coatings applied by PVD (physical vapor deposition), coatings applied by CVD (chemical vapor deposition), and / or coatings applied by slab printing. Furthermore, the process monitoring area may include a perforated structure or a strip-shaped structure, such as a raised edge structure or a channel structure. The strip-shaped structure is preferably formed in the tab by raising, deep drawing, or hydroforming. Additionally, the process monitoring area may have a laser structure, which is generated by means of a laser, or a molten structure, which is generated by melting the tab material. Furthermore, the process monitoring area may be treated with solvents, cleaning agents, or plasma.

[0019] In addition to explicit elements incorporated into or applied to a surface, or as an alternative, tabs can also be used to inspect the sheet metal material itself. In this case, at least a portion of the process monitoring area can remain untreated and uncoated for testing the sheet metal material.

[0020] In particular, by means of tabs, at least some or even all of the processing steps can be replicated on the same sheet material under the same processing conditions.

[0021] As described above, only one partition may have a tab. However, it is also possible to arrange two partitions, each having at least one of the aforementioned tabs. The tabs may be arranged at different locations on the respective partitions. Optionally, the tabs may at least partially or completely overlap in a direction perpendicular to the plane of the bipolar plate. Sometimes, the tabs of the partitions may contact each other, for example, in the contact area. To check the quality of the connection between the two partitions, separable overlapping tabs may also be connected to each other. After separating the tabs, the connection of the tabs can then provide information and conclusions about the connection between the two partitions. In one possible embodiment, the tabs are connected to each other by means of material bonding. This material bonding may be particularly provided in a process monitoring area for this purpose. Possible material bonding portions include welded joints, brazed joints, and / or adhesive bonding portions.

[0022] Each of the baffles or flow plates is preferably made of a metal plate, with metals such as stainless steel and / or titanium being suitable for the metal plate. The tabs and the plate body of at least one baffle are made of the same base material. However, the surface structure of the tabs may locally differ from the surface structure of the plate body; see the description above regarding the process monitoring area.

[0023] Although the tabs formed on the outer edge of the separator or bipolar plate can theoretically remain on the outer edge during fuel cell system operation, the tabs formed on the inner edge of the through opening of the separator or bipolar plate must be separated no later than before the fuel cell system is commissioned.

[0024] According to another aspect, a retained sample of a bipolar plate for an electrochemical system is provided. The retained sample includes a tab with a first fracture edge, which can be separated from the bipolar plate via a predetermined fracture point. In other words, the predetermined fracture point extends along the first fracture edge. The tab has a process monitoring area and / or a first code associated with the bipolar plate and / or its separator. The bipolar plate may specifically correspond to the bipolar plate mentioned above, with the tab separated from the bipolar plate and used as the retained sample. This retained sample enables post-production traceability of the bipolar plate. In particular, if the finished bipolar plate has already been delivered to or installed at the customer's site, the retained sample can be used for alternative representative analysis of the bipolar plate components at the manufacturer. Therefore, the bipolar plate does not need to be returned to the manufacturer.

[0025] According to another aspect, a system is provided comprising the aforementioned retained sample and an associated bipolar plate for an electrochemical system. The bipolar plate includes two separators connected to each other, and the bipolar plate has a second fracture edge having a shape complementary to the first fracture edge. The first and / or second fracture edges may each have an edge geometry characterized by the type of separation used (laser, power surge, cutting, etc.).

[0026] The above-described application is applied not only to the multiple identical bipolar plates used in a fuel cell stack, but also to the respective flow plates of the last pair of separators in the stack, also known as unipolar plates. At least one of the flow plates in this pair of separators may have some different characteristics compared to the separators described above, but may also have at least one tab for the various uses mentioned above.

[0027] According to another aspect, a flow plate for an electrochemical system is proposed, the flow plate having a plate body and at least one tab formed as a single piece with the plate body and separable from the plate body via a predetermined break point.

[0028] Although the bipolar plate described above has two septa connected to each other, the flow plate mentioned herein does not necessarily have two plates connected to each other. In particular, the flow plate can be constructed as a single-layer plate, especially a single-layer septa. The features described above for the (related) predetermined break points, tabs, and / or retained samples disclosed for connection with the bipolar plate and / or septa, as long as they are suitable for use in a single-layer plate, can also be combined with the flow plate. Therefore, the aforementioned retained samples and the aforementioned system can also be used and claimed with the flow plate. The flow plate can be constructed, for example, as a single-layer plate, a bipolar plate, a humidifier plate, and / or a septa. The flow plate can be made of, for example, metal or plastic.

[0029] An electrochemical system is also proposed, comprising multiple stacked bipolar plates and / or flow plates of the aforementioned type. This electrochemical system can be, for example, a fuel cell system, an electrochemical compressor, a redox flow battery, a humidifier for another electrochemical system, or an electrolyzer.

[0030] A method for manufacturing bipolar plates is also proposed. This method includes the following steps:

[0031] -Provide the board,

[0032] - Form a first partition, which has a plate body and at least one tab formed as a single piece with the plate body.

[0033] - A material weakening section is introduced into the first partition to form a predetermined fracture point, through which the tab can be separated from the main body of the partition.

[0034] - Provide a second partition.

[0035] - A bipolar plate is formed by connecting the first partition to the second partition.

[0036] The method may then include additional steps:

[0037] - Separate the protrusion from the first partition along the predetermined break point.

[0038] The aforementioned retained sample can be obtained by separating the tabs. The tabs can be separated by applying energy, such as heat, particularly by means of laser radiation, electric surge, or inductance. For this purpose, a suitable energy source can be used, that is, in particular a laser source, current source, or inductor source. One advantage of the above steps is that sharp edges and burrs can be avoided, which often occurs in the case of mechanical separation. Alternatively, the tabs can also be separated mechanically or chemically. Typically, the tabs are not separated from their respective septa until the two septa are already joined.

[0039] A method for producing a retained sample of a flow plate for use in an electrochemical system is also provided. The method includes the following steps:

[0040] -Provide the board,

[0041] - Forming a flow plate having a plate body and at least one tab formed as a single piece with the plate body.

[0042] - A material weakening section is introduced into the flow plate to form a predetermined fracture point, through which the tab can be separated from the plate body.

[0043] Subsequently, the tabs can be separated from the flow plate along a predetermined break point, particularly in the manner described above.

[0044] The flow field is typically integrally formed within the flow plate, for example, through methods such as punching, hydroforming, and / or deep drawing. This flow field usually comprises multiple channels and / or webs designed to guide fluid along the flow plate. Typically, the tabs are not separated from the flow plate until the flow field has been established.

[0045] This separation can be performed after all production steps in the manufacturing process of the flow plate, separator, and / or bipolar plate have been completed. However, it is also possible for the separation step to be performed after some of the production steps have been completed. Although in principle it is possible to separate the tabs from a row of plates (separators, flow plates, and / or bipolar plates) while these plates are still connected together in the strip material, it is preferred that the separation occurs when these plates are already in the form of individual plates, that is, when the plates have been separated from the strip material.

[0046] These methods are particularly suitable for producing the bipolar plates, flow plates, and / or retained samples described above. The characteristics described only relating to the bipolar plates, flow plates, and / or retained samples may also be required for use in this method, and vice versa.

[0047] A method for testing indwelling samples of bipolar plates or flow plates is also proposed. The bipolar plate includes two separators connected to each other, at least one of which has a plate body and at least one tab, the tab being formed as a single piece with the plate body and separable from the plate body via a predetermined fracture point. The flow plate includes a plate body and at least one tab, the tab being formed as a single piece with the plate body and separable from the plate body via a predetermined fracture point.

[0048] The tab is attached to the plate body during the production of the bipolar plate or flow plate, and subsequently separated from the plate body. Specifically, the tab can be attached to the bipolar plate or flow plate throughout the entire production process.

[0049] Furthermore, the separated protrusions are designed to serve as a sample retention medium for bipolar plates or flow plates. The method includes the following steps:

[0050] - Test at least one material property or one processing parameter of the retained sample.

[0051] In further steps, conclusions can be drawn about the properties of the bipolar or flow plate, particularly its surface, based on the retained sample. It should be noted that the separation and testing steps can be performed directly one after the other, thus both steps can be completed within, for example, a day, an hour, or less. However, the testing step can also be performed later, for example, at the manufacturer's location, while the bipolar or flow plate is at the buyer's or customer's location. Therefore, any complaints can be tracked and evaluated. Traceable coding (see the first coding mentioned above) can further facilitate time-shift analysis of the retained sample.

[0052] In general, a retained sample can provide a specimen of a bipolar plate or flow plate that has undergone the same processing steps as the bipolar plate or flow plate. Therefore, the performance of the bipolar plate or flow plate can be tested based on the retained sample without testing the bipolar plate or flow plate itself. The tabs can be tested non-destructively. Alternatively, destructive testing of the tabs can also be provided. In the case of destructive testing, the advantage of testing the retained sample is that it does not require breaking or damaging the bipolar plate or flow plate. This also applies to flow plates or separators before the two separators are assembled into a bipolar plate.

[0053] It can be provided that at least one tab has at least one process monitoring area, which, along with the plate body, is respectively structured, processed, and / or coated during the production of the flow plate, separator, or bipolar plate.

[0054] The characteristics of production methods and testing methods can be combined with each other. The characteristics of bipolar plates, flow plates, retained samples, and systems can also be combined with testing methods, and vice versa. Attached Figure Description

[0055] Exemplary embodiments of the present invention will now be explained in more detail with reference to the accompanying drawings. In the drawings:

[0056] Figure 1 An electrochemical system is schematically illustrated in a three-dimensional view, comprising a plurality of separators or bipolar plates arranged in a stacked manner;

[0057] Figure 2 A three-dimensional diagram schematically illustrates the following based on Figure 1 The system has two bipolar plates, with a membrane electrode assembly (MEA) arranged between the bipolar plates;

[0058] Figure 3 A schematic plan view of a bipolar plate with multiple separable tabs is shown, which can be used in... Figure 1 In the stack;

[0059] Figure 4 A schematic plan view of a portion of a bipolar plate with multiple separable tabs is shown, which can be used in... Figure 1 In the stack.

[0060] Figure 5 The schematic diagram shows the process. Figure 4 A cross-sectional view of a portion of the bipolar plate;

[0061] Figure 6 A detailed view of the tab is schematically shown, which is connected to the bipolar plate via a predetermined break point;

[0062] Figure 7 shows three sub- Figure 7A , 7B 7C schematically shows Figure 6 A cross-sectional view of the possible predetermined fracture point;

[0063] Figure 8 A schematic plan view of a portion of a bipolar plate is shown, which has two separable tabs, one on top of the other.

[0064] Figure 9 Schematic illustration along Figure 8 The cross-section of the section line BB, and the section used for separation Figure 8 The steps for the method of creating the convex tabs on a bipolar plate;

[0065] Figure 10 A schematic plan view of a portion of a bipolar plate is shown, the bipolar plate having two separable tabs, one completely on top of the other; and

[0066] Figure 11 Schematic illustration along Figure 10 A cross-sectional view taken from the CC section line.

[0067] In the following description and figures, repeated and functionally identical features have the same reference numerals. Detailed Implementation

[0068] Figure 1 An electrochemical system 1 is shown comprising multiple identical metal bipolar plates 2 arranged in a stack 6 and stacked along a z-direction 7. The bipolar plates 2 of the stack 6 are sandwiched between two end plates 3, 4. The z-direction 7 is also referred to as the stacking direction. In this example, system 1 is a fuel cell stack. Therefore, each pair of adjacent bipolar plates 2 in the stack encloses an electrochemical cell between them, which is used, for example, to convert chemical energy into electrical energy. To form the electrochemical cell of system 1, a membrane electrode assembly (MEA) 10 is arranged between each pair of adjacent bipolar plates 2 in each case (see, for example, [link to relevant documentation]). Figure 2Each MEA typically contains at least one membrane, such as an electrolyte membrane, and electrodes. Additionally, a gas diffusion layer (GDL) may be disposed on one or both surfaces of the MEA.

[0069] In alternative embodiments, system 1 may also be configured as an electrolyzer, an electrochemical compressor, a humidifier for an electrochemical system, or a redox flow battery. Bipolar plates can also be used in these electrochemical systems. Thus, the structure of these bipolar plates can correspond to the structure of bipolar plate 2 described in detail herein, but in each case of an electrolyzer, electrochemical compressor, humidifier for an electrochemical system, or redox flow battery, the medium conducted to and / or through the bipolar plates may differ from the medium used in fuel cell systems.

[0070] The z-axis 7, x-axis 8, and y-axis 9 form a right-handed Cartesian coordinate system. Each bipolar plate 2 defines a plate plane, and each plate plane of the partition is oriented parallel to the xy plane and therefore perpendicular to the stacking direction or z-axis 7. The end plate 4 has multiple medium ports 5 through which medium can be supplied to and discharged from system 1. The medium that can be supplied to and discharged from system 1 may include, for example, fuels such as molecular hydrogen or methanol, reaction gases such as air or oxygen, reaction products such as water vapor or depleted fuel, or coolants such as water and / or ethylene glycol.

[0071] Figure 2 Show in 3D Figure 1 The system is an electrochemical system of type 1, consisting of two adjacent bipolar plates 2, 2', and a prior art known membrane electrode assembly (MEA) 10 arranged between the adjacent bipolar plates 2, 2'. Figure 2 The MEA10 is largely obscured by the bipolar plate 2 facing the observer. The bipolar plate 2 is formed by two septa 2a and 2b bonded together by a material. Figure 2 Only the first partition 2a facing the observer is visible, and the first partition obscures the second partition 2b. The partitions 2a and 2b are typically formed as separate plates, each made of sheet metal, such as stainless steel. The partitions 2a and 2b are typically joined together by material bonding, and can be welded together, for example, by laser welding.

[0072] Partitions 2a and 2b typically have through openings that are aligned with each other and form through openings 11a-11c of bipolar plate 2. When multiple bipolar plates of the same type as bipolar plate 2 are stacked, the through openings 11a-11c form conduits extending along the stacking direction 7 through the stack 6 (see...). Figure 1Typically, each line formed by the through openings 11a-11c is fluidly connected to one of the ports 5 in the end plate 4 of system 1. For example, coolant can be introduced into or discharged from the stack via the line formed by through opening 11a. Conversely, the lines formed by through openings 11b, 11c can be configured to supply fuel and reaction gases to the electrochemical cells of the fuel cell stack 6 of system 1 and to discharge reaction products from the stack. The through openings 11a-11c for medium guidance are substantially parallel to the plate plane.

[0073] To seal the through openings 11a-11c relative to the interior of the stack 6 and relative to the surrounding environment, the first partition 2a typically has a sealing arrangement in the form of sealing flanges 12a-12c, which are respectively arranged around the through openings 11a-11c and, in each case, completely surround the through openings 11a-11c. On the back side of the bipolar plate 2... Figure 2 On the rear side of the observer, the second partition 2b has corresponding sealing convex edges for sealing the through openings 11a-11c (not shown).

[0074] In the electrochemically active region 18, the first separator 2a faces its orientation Figure 2 A flow field 17 is present on the front side of the observer, which has a structure for guiding the reaction medium along the front side of the partition 2a. Figure 2 In this structure, these structures are defined by multiple webs and channels extending between and defined by these webs. The electrochemically active region 18 may have at least one coating in certain areas, such as in the web regions or throughout the entire surface. Specifically, a corrosion-reducing coating may be provided throughout the entire surface, and / or a conductivity-enhancing coating 130 may be provided in at least certain areas. At bipolar plates 2, 2' facing... Figure 2 On the observer's front side, each of the first partitions 2a additionally has a distribution or collection area 20. This distribution or collection area 20 includes structures configured to distribute and / or collect or aggregate media on the active region 18, the distributed media being media already introduced into the distribution or collection area 20 from the first of the two through openings 11b, and / or the collected or aggregated media being media flowing from the active region 18 to the second of the through openings 11b. Figure 2 In this context, the distribution structure of the distribution or collection area 20 is also defined by webs and channels extending between the webs and defined by the webs. Generally speaking, elements 17, 18, and 20 can therefore be understood as raised structures for medium conduction.

[0075] The sealing flanges 12a-12c typically have passages 13a-13c, which are configured as partial protrusions of the flanges. Passage 13a is formed on the underside of the upper partition 2a (facing the observer) and on the upper side of the lower partition 2b (facing away from the observer), while passage 13b is formed in the upper partition 2a and passage 13c is formed in the lower partition 2b. For example, passage 13a allows coolant to pass between the through opening 11a and the distribution area, allowing the coolant to reach and be guided out of the distribution area between the partitions. Furthermore, passage 13b allows hydrogen to pass between the through opening 11b and the distribution area 20 on the upper side of the upper partition 2a; these passages 13b are characterized by perforations facing the distribution area and extending at an angle to the plate plane. Therefore, hydrogen gas flows, for example, from the through opening 11b through the passage 13b to the distribution area on the upper side of the upper partition 2a, or in the opposite direction. The passage 13c allows air to pass, for example, between the through opening 11c and the distribution area, so that the air reaches the distribution area on the lower side of the lower partition 2b and is guided out therefrom. The associated perforations are not visible here.

[0076] The first baffle 2a typically also has an additional sealing arrangement in the form of a peripheral protrusion 12d, which extends around the flow field 17 of the active region 18, the distribution or collection region 20, and the through openings 11b, 11c, and seals these with respect to the through openings 11a, i.e., with respect to the coolant circuit and with respect to the surrounding environment of the system 1. The second baffle 2b each includes a corresponding peripheral protrusion. The structure of the active region 18, the distribution or collection structure of the distribution or collection region 20, and the sealing protrusions 12a-12d are each formed integrally with the baffle 2a, and integrally formed in the baffle 2a, for example by a embossing process, hydroforming process, or deep drawing process. The same applies to the corresponding distribution structure and sealing protrusion of the second baffle 2b. A predominantly unstructured outer edge region 22 is obtained in each baffle 2a, 2b outside the area enclosed by the peripheral protrusion 12b.

[0077] At least some of the aforementioned sealing protrusions may be at least partially coated on at least one of their surfaces, for example, at least partially coated at the top of the protrusion. Polymer-based coatings that improve micro-sealing are suitable for this purpose. Pretreatment, such as a cleaning step or surface treatment, may be performed before coating application.

[0078] As an alternative to the aforementioned sealing protrusion integrally formed with the partition, other sealing elements may be used, such as sealing profiles inserted into surface recesses or sealing profiles 120 coated on the surface, such as... Figure 10 and 11As shown. Each of the partitions 2a and 2b is typically formed of sheet metal with a thickness between 60 μm and 150 μm. Due to the relatively small thickness of individual plates 2a and 2b, and also due to their relatively large dimensions in the Y and X directions, plates 2a and 2b are relatively easily mechanically deformed and damaged. However, due to numerous functional areas, such as the flow field 17, active region 18, distribution or collection region 20, through openings 11a-11c, and convex edge arrangements 12a-12d, plates 2a and 2b should only be manipulated within their largely unstructured edge regions 22 to avoid contamination. Therefore, in general, plates 2a and 2b may be difficult to manipulate; this applies to both manual manipulation and manipulation using an automated gripping system.

[0079] Figure 3 A schematic plan view of a bipolar plate 2 composed of separators 2a and 2b is shown, which can be used in a stack 6 of an electrochemical system 1. Figure 3 Only the first partition 2a is visible, as it completely covers the second partition 2b. (With) Figure 2 Compared to the plates 2', 2a, and 2b shown, the partition 2a includes a plate body 21 and at least one additional tab 30, 31. The tabs 30, 31 are formed as one piece with the plate body 21 and can be separated from the plate body 21 via a predetermined break point 33.

[0080] exist Figures 3-11 In an exemplary embodiment, tabs 30 and 31 extend parallel to the plate plane defined by the plate body 21. In an alternative embodiment, tabs 30 and 31 may also be arranged at an angle to the plate plane. Tabs 30 and 31 may be arranged at different locations on the bipolar plate. For example, tab 30 is arranged on the outer edge of the bipolar plate 2 and protrudes laterally from the plate body 21, resulting in relatively more space for tab 30 and relatively easy separation and manipulation of tab 30. Tab 31 is arranged on the inner edge of the through opening 11c. Therefore, material from a metal plate that would otherwise be discarded during the production of the through opening 11c can be used to produce tab 31 in the through opening 11c.

[0081] Figure 5 and Figures 7A-7C A cross-section through various predetermined fracture points 33 is shown. Each predetermined fracture point 33 has a width b measured perpendicular to its longitudinal extension direction. Therefore, the predetermined fracture point 33 may have a notch 34, which is, for example, V-shaped and has an opening angle α. Figure 7A ) or U-shaped with a maximum width b ( Figure 7BThe notch 34 is designed here as a material weakening section with a maximum depth t, and the residual thickness of the material is formed by the difference between the thickness d of the tab 30 and the depth t of the notch 34. The predetermined break point 33 may alternatively or additionally also have a plurality of through holes 35 with a diameter of b. Figure 7C The predetermined fracture point 33 can be formed, for example, by engraving, punching, laser radiation, or using electric current combustion. Figure 3 , Figure 4 , Figure 6 , Figure 8 and Figure 10 As shown, the predetermined break point 33 can lead to the widened cut between the tab 30 and the plate body 21. The predetermined break point 33 can extend along the plate plane in a predominantly arcuate manner.

[0082] To facilitate easier separation of the tab along the predetermined break point 33 without damaging the bipolar plate 2, at least one reinforcing structure 36, 37, 12c can be provided, extending along the predetermined break point 33. Figure 3 In the protrusion 30, a reinforcing structure 36 is provided on the main body 21 of the plate, and Figure 4 , Figure 6 and Figure 8 The tab 30 has reinforcing structures 36 and 37 on both sides of the plate body 21 and the tab 30 at the predetermined fracture point 33. Figure 3 and Figure 4 In the tab 31, the protruding edge 12c through the opening 11c forms a reinforcing structure. The tabs 30 and 31 may have at least one reinforcing structure 38 for strengthening them. The reinforcing structures 36, 37, and 38 may be designed as raised or recessed structures, such as protruding edges (see...). Figures 3-9 ), small pieces or domes (see Figure 10 ).

[0083] Lugs 30 and 31 can, for example, facilitate the manipulation of the bipolar plate 2 or individual septa 2a and 2b. Typically, lugs 30 and 31 are configured for transporting, positioning, holding, and / or gripping the bipolar plate 2 or individual septa 2a and 2b. For instance, lugs 30 and 31 have a substantially flat or structured holding area 43 where lugs 30 and 31 can be manipulated and held without contaminating or mechanically deforming the plate body 21 of the septa 2a and 2b. This is in… Figure 4 , Figure 6 and Figure 8The fingerprint is used as a symbol. The holding area 43 can also be held by a suction lifting tool, other lifting tools, or a suction cup. As a further measure for transport, holding, positioning, and gripping, the tabs 30, 31 may have positioning openings 45 for receiving the centering pin of the centering device or for checking the relative position of the two partitions 2a, 2b of the bipolar plate 2. Preferably, the predetermined break point 33 is configured such that it will not break or plastically deform under the weight of the bipolar plate 2.

[0084] The tabs 30 and 31 can be designed as samples to be retained. For this purpose, the tabs 30 and 31 are separated from and stored on the bipolar plate 2. Separation along a predetermined break point 33 results in fracture edges appearing on both one side of the tabs 30 and 31 and one side of the bipolar plate. Therefore, the tabs 30 and 31, separated from the bipolar plate 2 and designed as samples to be retained, have a first fracture edge whose shape is complementary to the second fracture edge of the bipolar plate 2. Designing the tabs 30 and 31 as samples to be retained allows for the traceability of the bipolar plate 2. In particular, a system consisting of the retained samples 30 and 31 and the bipolar plate 2 can be formed for quality control.

[0085] To simplify traceability, the tabs 30 and 31 may have a first code 41, which is associated with the bipolar plate 2 (see [link]). Figure 4 , Figure 6 and Figure 10 Furthermore, the bipolar plate 2 may have a second code 42, which is associated with the tabs 30 and 31 and corresponds to the first code 41. Figure 4 and Figure 10 In an exemplary embodiment, the corresponding codes 41 and 42 are constructed as inscriptions, particularly numerical codes, but they may also be alternatively or additionally constructed as patterns, such as barcodes, particularly as... Figure 6 The data matrix code or 2D code of QR code can be constructed as a colored pattern, perforated pattern and / or embossed pattern. The corresponding codes 41, 42 may also include chips, such as RFID.

[0086] exist Figure 4 , Figure 6 and Figure 10 In the embodiments, the tabs 30, 31 include at least one process monitoring area 44. As an example, multiple process monitoring areas 44 may be provided on one or both sides of the tabs 30, 31. At least one surface treatment portion 141 (which here has a slight ablation effect), coatings 121, 131 (on... Figure 10 and 11In the example, the applied sealing element is also considered as a sealing coating 121) and / or structure that can be applied to or included in the process monitoring area 44, and can also be applied to at least a portion of the bipolar plate 2, i.e., as a surface treatment section 140, as a contoured sealing coating 120, and as a conductive coating 130. Suitable coatings include, for example, sealing coatings 120, 121 (here, a sealing contour), adhesive coatings, conductive coatings 130, 131, or anti-corrosion coatings. At least one coating 121, 131 can be a coating applied by screen printing, a coating applied by a knife, a spray coating, a coating applied by PVD (physical vapor deposition), a coating applied by CVD (chemical vapor deposition), and / or a coating applied by pad printing. Such coatings are typically applied to the bipolar plate 2 or the separators 2a, 2b. Suitable structures include, for example, raised structures, laser structures, and / or fused structures. Suitable surface treatments are treatments of the raised surface using solvents, cleaning agents, or plasma. Figure 10 Reference numeral 44 is omitted in the figures; elements 111 (laser weld), 121 (sealing coating, sealing profile), 131 (conductive coating) and 141 (pretreatment section) each represent process monitoring areas for similar elements in the board body, which are indicated thereby by reference numerals 110 (laser weld), 120 (sealing coating, sealing profile), 130 (conductive coating) and 140 (pretreatment section).

[0087] In addition to being incorporated into or applied to specific elements in the process monitoring area 44, or as an alternative, the process monitoring area 44 can also be used to inspect the sheet metal material of the partitions 2a, 2b. In this case, at least a portion of the process monitoring area 44 can remain unstructured, untreated, and uncoated for testing the sheet metal material.

[0088] With the help of the process monitoring area 44, subsequent indirect analysis of the bipolar plate 2 can be performed without removing the bipolar plate 2 already installed in the electrochemical system 1. Therefore, both non-destructive and destructive analysis of the tabs 30 and 31 are possible.

[0089] The base materials of the tabs 30, 31, and 32 are the same as those of the main body 21. However, the surface structure of the tabs, especially the surface structure of the process monitoring area 44, may have local differences from the surface structure of the main body 21.

[0090] The tabs 30 and 31 may be provided in only one of the two partitions 2a and 2b. However, it is also possible that both partitions 2a and 2b have tabs 30 and 31. For example, Figure 8Two tabs 30 and 32 are shown. Tab 30 is part of partition 2a, and tab 32 is part of partition 2b. Tab 32 may have the same characteristics as tab 30; however, tabs 30 and 32 may also have different features. For example, each tab may be equipped with different functional elements, such as a code 41, a process monitoring area 44, a holding area 43, and / or a positioning opening 45. Figure 8 and Figure 9 As shown, tabs 30 and 32 are arranged at different positions on the respective partitions 2a and 2b. Tabs 30 and 32 can be arranged such that they partially overlap in a direction perpendicular to the plane of the bipolar plate 2 (z-direction). Tabs 30 and 32 can be selectively welded together in the contact area, or otherwise connected to each other by material bonding. The welding positions 111 used for this purpose can, for example, be located in their respective process monitoring areas 44, so that the quality or defects of the welding positions can be inspected later, thus confirming the quality or defects of the welding positions 110 of the plate body. Furthermore, in such cases, i.e., the double-layer tabs 39 separated from the bipolar plate as... Figure 10 and 11 As shown in the unseparated state, the plate bodies of the partitions can be checked via the positioning elements 45 in each of these layers to see if they are also in the correct position relative to each other, or are already in the correct position to be connected. If the edges of the positioning elements 45 of the two tabs 30, 32 are flush, the two partitions 2a, 2b are in the optimal position relative to each other, and the corresponding positioning elements 45 are advantageously provided in at least two pairs of tabs.

[0091] A method for producing bipolar plate 2 is also proposed. This method includes the following steps:

[0092] -Provide the board,

[0093] - A first partition 2a is formed, which has a plate body 21 and at least one tab 30, 31 formed as a single piece with the plate body 21.

[0094] - A material weakening portion is introduced into the first partition 2a to form a predetermined fracture point 33, through which the tabs 30 and 31 can be separated from the plate body 21.

[0095] - Provide a second partition 2b,

[0096] - A bipolar plate 2 is formed by connecting a first partition 2a to a second partition 2b, the connection being made by material bonding.

[0097] Thus, the tabs 30 and 31 can be separated from the first partition 2a along a predetermined break point. This separation can be carried out under the influence of heat, such as by means of laser radiation, electrical surge, or inductance. Alternatively, the tabs 30 and 31 can be mechanically separated from the plate body 21, for example by cutting or tearing it off.

[0098] The second partition 2b can also have a corresponding tab 32. Figure 9 The arrow in the middle shows Figure 8 The tabs 30 and 32 of the bipolar plate 2 are joined together, and the material of the partially overlapping tabs 30 and 32 is bonded. Afterwards, the tabs 30 and 32 can be peeled off from the bipolar plate 2 in a counter-clockwise direction (see arrow). If the two tabs 30 and 32 (or tabs 31 and 32) are connected before separation, they form a double-layer tab 39, as shown. Figure 10 and 11 As shown in the figure; welded joint 111 is clearly shown in the figure.

[0099] In the manufacturing process, the process monitoring area 44 of the plate body 21 on one hand and the tabs 30, 31, 32, 39 on the other hand can undergo the same processing steps, especially coating, surface treatment and / or structuring, so the subsequently separated tabs 30, 31, 32, 39 can be used for, for example, quality control or quality assurance.

[0100] A method for testing retained samples 30, 31, 32, and 39 of bipolar plate 2 is also proposed. First, the tabs 30, 31, and 32 still attached to the plate body 21 and the plate body 21 are each structured, surface-treated, inscribed, coated, embossed, punched, and / or welded in the same or at least similar manner. Subsequently, the retained samples 30, 31, 32, and 39 are separated from the plate body 21. The method includes at least the following steps:

[0101] - Test at least one material property or one processing parameter of the retained samples 30, 31, 32, and 39.

[0102] The process monitoring areas 44 of tabs 30, 31, 32, and 39 are particularly suitable for testing. Since the process monitoring areas 44 undergo the same processing steps as the main body 21, the characteristics of the bipolar plate 2 can be tested using retained samples 30, 31, 32, and 39 without having to test the bipolar plate 2 itself. Figure 10 In the example, the sealing element 121, conductive coating 131, weld 111 and surface pretreatment part 141 are applied to or incorporated into the plate body 21, the tab 30 of the upper partition 2a and the tab 32 of the lower partition 2b.

[0103] For example, destructive tests can be performed on the retained samples 30, 31, 32, and 39 without damaging the bipolar plate 2 itself. Of course, non-destructive tests can also be performed.

[0104] The characteristics of the above method can be combined with the characteristics of bipolar plate 2 and separators 2a and 2b, and vice versa.

[0105] The features described above and shown in the figures, disclosed as relating to the predetermined break point 33, tabs 30, 31, and / or the retention samples 30, 31, in connection with the double-layer bipolar plate 2 and the separators 2a, 2b, can also be combined with a single-layer flow plate (not shown), provided they are adaptable for use in a single-layer flow plate. Therefore, the aforementioned retention samples 30, 31 and the aforementioned system can also be used with and claimed with a flow plate. The flow plate can be constructed, for example, as a monopolar plate, bipolar plate, humidifier plate, and / or separator, and can be made, for example, of metal or plastic.

[0106] List of reference numerals in the attached diagram:

[0107] 1. Electrochemical System

[0108] 2 Bipolar plates

[0109] 2' bipolar plate

[0110] 2a partition

[0111] 2b partition

[0112] 3 end plates

[0113] 4 end plates

[0114] 5. Media Port

[0115] 6 stacking

[0116] 7 Z direction

[0117] 8 X direction

[0118] 9 Y direction

[0119] 10 Membrane Electrode Assembly

[0120] 11a-11d Through opening

[0121] 12 Convex edge arrangement

[0122] 12' Convex Edge Arrangement

[0123] 12a-12d Convex edge arrangement

[0124] 13a-13c pathway

[0125] 17 Flow Field

[0126] 18 Electrochemical active regions

[0127] 20. Allocation and / or collection areas

[0128] 21-panel main body

[0129] 22 Unstructured external regions

[0130] 30 Separable tabs, optionally also for sample retention.

[0131] 31 Separable tabs, optionally also for sample retention.

[0132] 32 Separable tabs, optionally also for sample retention.

[0133] 33. Predetermined break point

[0134] 34 Notch

[0135] 35 perforations

[0136] 36. Strengthen the structure

[0137] 37. Strengthen the structure

[0138] 38. Strengthen the structure

[0139] 39. Retained sample or separable double-layered sheet

[0140] 41 First Code

[0141] 42 Second Code

[0142] 43. Maintaining area

[0143] 44 Process Monitoring Area

[0144] 45 Positioning opening

[0145] 110 Weld (Plate Body)

[0146] 111 Weld (Given)

[0147] 120 Sealing element (plate body)

[0148] 121 Sealing element (lamp)

[0149] 130 Conductive coating (board body)

[0150] 131 Conductive coating (embossed)

[0151] 140 Surface Pretreatment Section (Main Board)

[0152] 141 Surface pretreatment section (protrusion)

[0153] t Depth of the notch

[0154] d Thickness of the convex piece

[0155] b. Width of the predetermined break point

Claims

1. A bipolar plate (2) for an electrochemical system (1), the bipolar plate (2) comprising two separators (2a, 2b) connected to each other, at least one of the separators (2a, 2b) having a plate body (21) and at least one tab (30, 31, 32), the at least one tab (30, 31, 32) being formed as a single piece with the plate body (21) and separable from the plate body (21) via a predetermined break point (33), in, The tabs (30, 31, 32) have a first code (41) associated with each partition (2a, 2b) and / or bipolar plate (2), and the partitions (2a, 2b) and / or the bipolar plate (2) have a second code (42) corresponding to the first code (41) on the tabs (30, 31, 32).

2. The bipolar plate (2) according to claim 1, characterized in that, Includes at least one through opening (11a-11c) for fluid passage, with the tabs (30, 31, 32) arranged on the inner edge of the through opening (11a-11c) or the outer edge of the plate body (21).

3. The bipolar plate (2) according to claim 1, characterized in that, A reinforcing structure, which extends at least partially along the predetermined break point (33), is used to separate the tabs (30, 31, 32) along the predetermined break point (33) in a defined manner, the reinforcing structure being arranged on at least one side of the predetermined break point (33).

4. The bipolar plate (2) according to claim 1, characterized in that, The tabs (30, 31, 32) have at least one additional reinforcing structure for reinforcing the tabs (30, 31, 32).

5. The bipolar plate (2) according to any one of claims 3 or 4, characterized in that, The corresponding reinforcing structure is constructed as a convex structure, a convex edge, or a group of floating protrusions.

6. The bipolar plate (2) according to claim 1, characterized in that, The predetermined break point (33) includes a notch (34) and / or a perforation (35).

7. The bipolar plate (2) according to claim 1, characterized in that, The first code and the second code include inscriptions, colored patterns, perforated patterns and / or embossed patterns.

8. The bipolar plate (2) according to claim 1, characterized in that, The tabs (30, 31, 32) have at least one process monitoring area (44).

9. The bipolar plate (2) according to claim 8, characterized in that, The at least one process monitoring area (44) has a coating (121, 131), a surface treatment section (141), and / or a structure, the structure including a raised structure, a laser structure, and / or a molten structure.

10. The bipolar plate (2) according to claim 1, characterized in that, The tabs (30, 31, 32) have positioning openings (45) for receiving centering pins or for position control.

11. The bipolar plate (2) according to claim 1, characterized in that, Each of the two partitions (2a, 2b) has the tabs that overlap at least partially in a direction perpendicular to the plane of the bipolar plate (2).

12. A retained sample of a bipolar plate (2) for an electrochemical system (1), the retained sample comprising tabs (30, 31, 32, 39) having a first fracture edge, the tabs (30, 31, 32, 39) being separable from the bipolar plate (2) via a predetermined fracture point (33), the tabs (30, 31, 32, 39) having a process monitoring area (44) and / or a first code (41) associated with the bipolar plate (2) and / or the separator of the bipolar plate (2).

13. A system comprising a retained sample according to claim 12 and a bipolar plate (2) for the electrochemical system (1), the bipolar plate (2) comprising two separators (2a, 2b) connected to each other, the bipolar plate (2) having a second fracture edge having a shape complementary to the first fracture edge.

14. A method for producing a bipolar plate (2) for use in an electrochemical system (1), the method comprising the steps of: -Provide the board, - A first partition (2a) is formed, the first partition (2a) having a plate body (21) and at least one tab (30, 31, 32) formed as a single piece with the plate body (21). - A material weakening portion is introduced in the first partition (2a) to form a predetermined fracture point (33), through which the tabs (30, 31, 32) separate from the plate body. - Provide a second partition (2b). - The bipolar plate (2) is formed by connecting the first partition (2a) to the second partition (2b). The tabs (30, 31, 32) have a first code (41) associated with each partition (2a, 2b) and / or bipolar plate (2), and the partitions (2a, 2b) and / or the bipolar plate (2) have a second code (42) corresponding to the first code (41) on the tabs (30, 31, 32).

15. The method of claim 14, wherein the method comprises the additional step: - Separate the tabs (30, 31, 32) from the first partition along the predetermined break point (33).

16. A method for testing a retained sample of a bipolar plate (2), the bipolar plate (2) comprising: Two interconnected partitions (2a, 2b), at least one of which has a plate body (21) and at least one tab (30, 31, 32, 39), the at least one tab (30, 31, 32, 39) being formed as a single piece with the plate body and separable from the plate body via a predetermined break point (33), the tab (30, 31, 32, 39) being attached to the plate body (21) while the bipolar plate (2) is being manufactured, and subsequently separating from the plate body, its In the method, the tabs (30, 31, 32, 39) are designed as the retained samples of the bipolar plate (2), wherein the tabs (30, 31, 32, 39) have a first code (41) associated with each partition (2a, 2b) and / or the bipolar plate (2), and the partitions (2a, 2b) and / or the bipolar plate (2) have a second code (42) corresponding to the first code (41) on the tabs (30, 31, 32, 39), and the method includes the following steps: - Test at least one material property or a processing parameter of the tabs (30, 31, 32, 39).

17. The method according to claim 16, characterized in that, At least one of the tabs (30, 31, 32, 39) has at least one process monitoring area (44), the process monitoring area (44) and the plate body (21) being structured, processed and / or coated in the production of the bipolar plate (2).

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