Bipolar plate and electrochemical unit

Abstract

In order to provide a bipolar plate (100) for an electrochemical unit which achieves optimized supply and discharge of a fluid medium to and from a membrane electrode unit, it is proposed that this bipolar plate comprises at least one plate body (102), on which a plurality of flow channels are provided that form at least one flow field (104) for a fluid medium, at least one medium inlet (106) for supplying the fluid medium and / or at least one medium outlet (108) for discharging the fluid medium is formed, and at least one sealing ridge (110) is provided which delimits the flow field (104), the at least one medium inlet (106) and / or the at least one medium outlet (108) in at least some portions and has a first ridge side wall (118) and a second ridge side wall (120), wherein at least one of the ridge side walls (118, 120) has different angles of inclination (N) at least in some portions with respect to a main plane of extent (122) of the plate body (102) and / or the ridge side walls (118, 120) have angles of inclination (N) which differ from each other at least in some portions.

Description

[0001] Bipolar plate and electrochemical unit

[0002] The present invention relates to a bipolar plate for an electrochemical unit and an electrochemical unit.

[0003] The core of a fuel cell consists of membrane electrode assemblies (MEAs), which are separated on the cathode and anode sides by bipolar plates. These bipolar plates have a channel structure that creates a flow field, through which reaction media are supplied to the MEAs and reaction products are removed. To prevent the escape of reaction media and products, the reaction space formed between the bipolar plates can be sealed by welding the cathode-side and anode-side bipolar plates together or by providing a gasket between them. Sealing between the bipolar plates can also be achieved by sealing ribs, so-called sealing beads, formed from the plate bodies. Within a fuel cell stack, uneven forces can act on such sealing ribs, which can lead to leakage currents and consequently to a reduction in fuel cell performance.

[0004] The present invention is based on the objective of providing a bipolar plate that enables optimized supply and discharge of a fluid medium to and from a membrane electrode assembly. Furthermore, the invention aims to provide an electrochemical unit with optimized performance potential.

[0005] This problem is solved by a bipolar plate for an electrochemical unit, comprising at least one plate body on which a plurality of flow channels are provided, which form at least one flow field for a fluid medium, at least one media inlet for supplying and / or at least one media outlet for removing the fluid medium is formed, at least one sealing rib is provided which delimits the flow field, the at least one media inlet and / or the at least one media outlet at least section by section and which has a first rib side wall and a second rib side wall, wherein at least one of the rib side walls has different angles of inclination at least section by section with respect to a principal extension plane of the plate body and / or the rib side walls have angles of inclination that differ from each other at least section by section.

[0006] The bipolar plate can preferably be formed from one layer of the plate body or from several layers of the plate body.

[0007] In particular, at least one of the plate bodies can be made of metal.

[0008] The at least one plate body can be provided with a coating, in particular with a conductive and / or corrosion-resistant coating, for example the at least one plate body can be coated with gold, titanium, titanium nitride, carbon, chromium nitride and / or a ceramic material.

[0009] The flow channels forming the flow field for the fluid medium are preferably formed on the at least one plate body, in particular formed from it, molded onto it or introduced into it.

[0010] At least one sealing rib is formed to limit the flow field, at least section by section, to an edge region of the bipolar plate, i.e., to an outside, and / or to the media supply and media discharge of the bipolar plate, which are also referred to as manifolds or headers.

[0011] Advantageously, at least one sealing rib extends fully along the edge area of ​​the bipolar plate and / or fully around the media supply and / or media discharge.

[0012] The at least one sealing ridge can thereby form a seal or boundary for the flow field to the edge area of ​​the bipolar plate and / or to the media supply and / or media discharge.

[0013] In an assembled state of the fuel cell unit, the at least one sealing rib can thus form a seal of the flow field to the outside and / or to the media supply and / or media discharge by bearing in a sealing manner against a membrane-electrode unit between adjacent bipolar plates. For this purpose, the at least one sealing rib is preferably indirectly pressed against the adjacent bipolar plate when several such bipolar plates are stacked on top of each other in the assembled state of the fuel cell unit.

[0014] The sealing rib could be an edge rib of the bipolar plate.

[0015] Preferably, the at least one sealing rib is formed as a groove, in particular as a sealing groove, on the plate body.

[0016] Preferably, the at least one sealing rib can be formed from the at least one plate body, molded onto the at least one plate body or incorporated into the at least one plate body.

[0017] In particular, the at least one sealing rib is integrally formed from the at least one plate body.

[0018] Preferably, the first side wall of the web and / or the second side wall of the web has different angles of inclination, at least in sections.

[0019] Consequently, the first and / or second web side wall may have one or more sections which are inclined at a shallower and / or steeper angle of inclination with respect to one or more other sections of the respective web side wall and the main extension plane of the plate body.

[0020] Alternatively or additionally, the first side wall of the web and the second side wall of the web have different angles of inclination, at least in sections.

[0021] Consequently, the first and second web sidewalls can each have one or more sections which are inclined at a shallower and / or steeper angle of inclination with respect to one or more sections of the other web sidewall and the main extension plane of the plate body.

[0022] Within the scope of this description and the claims, the inclination angle of the web sidewalls is understood to be an angle formed between the respective web sidewall and the principal extension plane of the plate body of the bipolar plate. The inclination angle is defined by an angle formed on a side of the respective web sidewall closest to the web and the principal extension plane of the plate body.

[0023] By having the first and / or second web sidewall have different angles of inclination at least in sections and / or by having the first and second web sidewall have different angles of inclination at least in sections, a sealing web can be formed which is provided with increased or decreased stiffness at least in sections and / or with increased or decreased elasticity at least in sections.

[0024] In this way, a sealing bridge can be designed with different properties in different bridge sections. For example, the properties of such a sealing bridge can be individually adapted in the area of ​​a curve, in the area of ​​a feedthrough, in the area of ​​a transition, or the like, so that in an assembly configuration in which a large number of bipolar plates are joined to form a fuel cell stack, an effective seal between the bipolar plates and an outside and / or to the media supply and / or to the media discharge can be achieved, thus reducing the risk of leakage.

[0025] By reducing or eliminating leakage flows, the escape of the fluid medium can be prevented, thus making a larger quantity of the fluid medium available as a reaction medium for the fuel cell reaction or as a cooling medium for the fuel cell process. Consequently, an electrochemical cell with such a bipolar plate can achieve optimized performance potential.

[0026] A further development of the bipolar plate can provide that at least one of the web sidewalls is inclined at different angles along a direction of extension of the sealing web and / or that the web sidewalls are inclined at different angles of inclination at least in sections along the direction of extension of the sealing web. Consequently, the first and / or second web sidewall can have one or more sections along the direction of extension of the sealing web that are inclined at a shallower and / or steeper angle of inclination relative to one or more other sections of the respective web sidewall with respect to the main plane of extension of the plate body.

[0027] Along the extension direction of the sealing web, the inclination angle of the first and / or second web side wall can be either uniform or change in steps.

[0028] In other words, the angle of inclination of the first and / or second web side wall can be uniformly or gradually becoming shallower and / or steeper along the extension direction of the sealing web.

[0029] It may be provided that the angle of inclination of the first and / or second web side wall is inclined uniformly or stepwise from a steeper angle of inclination to a shallower angle of inclination along the extension direction of the sealing web, or vice versa.

[0030] If the first web side wall and the second web side wall are inclined at different angles of inclination at least in sections along the extension direction of the sealing web, one of the web side walls can be inclined at a shallower angle of inclination or at a steeper angle of inclination than the other web side wall, at least in sections.

[0031] In a preferred embodiment of the bipolar plate, the inclination angles of the first web side wall and / or the second web side wall along the extension direction of the sealing web can exhibit a gradient that alternates between becoming shallower and steeper.

[0032] This means that the angles of inclination of the first and / or second web sidewalls along the direction of the sealing web can be uniformly or stepwise becoming shallower and steeper at multiple points. The shallower or steeper angle of inclination of the first and / or second web sidewalls can be formed within a defined section of the sealing web in order to achieve a corresponding stiffness and / or elasticity of the sealing web, depending on a required property characteristic.

[0033] Advantageously, the angles of inclination of the first web side wall and / or the second web side wall can be designed to become continuously shallower and steeper along the extension direction of the sealing web.

[0034] Preferably, the first web side wall and / or the second web side wall can have a cyclically flattening and steepening slope along the extension direction of the sealing web.

[0035] Within the scope of this description and the claims, a cyclically flattening and steepening angle of inclination of the first web side wall and / or second web side wall is understood to mean that the angle of inclination of the respective web side wall along the extension direction of the sealing web can be formed both in a constantly repeating inclination profile becoming steeper and flatter, and in a non-constant but regularly repeating inclination profile becoming steeper and flatter.

[0036] The angles of inclination of the first and / or second side wall of the sealing web, which become steeper and shallower in a constantly repeating inclination profile along the extension direction of the sealing web, can preferably be a periodic inclination profile of an alternatingly steeper and shallower angle of inclination.

[0037] An advantageous embodiment of the bipolar plate can provide that the inclination angles of the first web side wall and the inclination angles of the second web side wall along the extension direction of the sealing web have an inclination profile that is at least partially in phase with each other.

[0038] Alternatively or additionally, the inclination angles of the first web side wall and the inclination angles of the second web side wall along the extension direction of the sealing web can have an inclination profile that is phase-shifted relative to each other, at least in sections.

[0039] In particular, if the inclination angles of the first web side wall and / or the inclination angles of the second web side wall are formed in a periodically constant repeating inclination profile that becomes steeper and shallower, the periodic inclination profile of the inclination angles of the first web side wall and the second web side wall can be at least sectionally in phase with each other and / or at least sectionally out of phase with each other.

[0040] Preferably, the bipolar plate can be provided with at least one cycle of alternatingly shallow and steepening inclination angles of the first rib side wall and / or the second rib side wall along a length of the at least one sealing rib.

[0041] Preferably, it may be provided that along a length of the at least one sealing web, at least two cycles of alternating shallow and steepening angles of inclination of the first web side wall and / or the second web side wall are provided.

[0042] It is further preferably provided that along a length of the at least one sealing web at least five cycles of alternating shallow and steepening angles of inclination of the first web side wall and / or the second web side wall are provided.

[0043] It may be further preferably provided that along a length of the at least one sealing web at least ten cycles of alternating shallow and steepening angles of inclination of the first web side wall and / or the second web side wall are provided.

[0044] For example, over an extension length of the at least one sealing web of about 100 mm, at least one cycle, preferably at least two cycles, more preferably at least five cycles, more preferably at least ten cycles, of alternatingly shallower and steeper angles of inclination of the first web side wall and / or the second web side wall can be provided.

[0045] Within the context of this description and the claims, the term "approximately" is to be understood as a deviation from the specified value of + / - 20%, preferably + / - 10%, more preferably + / - 5%.

[0046] Another preferred embodiment of the bipolar plate can provide that the various inclination angles of the first web side wall and / or the second web side wall with respect to the main extension plane of the plate body are inclined between a minimum inclination angle of at least 10°, preferably at least 20°, more preferably at least 30°, and / or a maximum inclination angle of at most 85°, preferably at most 80°, more preferably at most 70°.

[0047] The maximum inclination angle of the first web side wall and / or the second web side wall can be defined, for example, by an angle between the respective web side wall and the main extension plane of the plate body of approximately 65°, + / - 20°, preferably + / - 10°.

[0048] The minimum inclination angle of the first web side wall and / or the second web side wall can be defined, for example, by an angle between the respective web side wall and the main extension plane of the plate body of approximately 30°, + / - 20°, preferably + / - 10°.

[0049] A preferred embodiment of the bipolar plate can provide that an angle difference of at least 5°, preferably at least 10°, more preferably at least 15°, and more preferably at least 20°, is provided between a minimum inclination angle and a maximum inclination angle of the first web side wall and / or the second web side wall.

[0050] Advantageously, a distance of at most approximately 100 mm, preferably at most approximately 50 mm, more preferably at most approximately 25 mm, and more preferably at most approximately 10 mm, can be formed in the direction of extension of the at least one sealing web between adjacent sections of the first web side wall and / or the second web side wall with minimum and maximum angles of inclination. In other words, the change in the angle of inclination of the first web side wall and / or the second web side wall with an angle difference of at least 5°, preferably at least 10°, more preferably at least 15°, and more preferably at least 20°, between a section with minimum angle of inclination and an adjacent section with maximum angle of inclination can be formed over a length of the at least one sealing web of at most approximately 100 mm, preferably at most approximately 50 mm, more preferably at most approximately 25 mm, and more preferably at most approximately 10 mm.

[0051] Advantageously, in the bipolar plate, an angle difference of at least 5°, preferably at least 10°, more preferably at least 15°, and more preferably at least 20° can be provided between the inclination angles of the first web side wall and the second web side wall, at least in sections.

[0052] Preferably, the angle difference can be at least 5°, preferably at least 10°, more preferably at least 15°, more preferably at least 20°, between opposing sections of the first web side wall and the second web side wall.

[0053] Equally preferably, the angle difference of at least 5°, preferably at least 10°, more preferably at least 15°, more preferably at least 20°, can be formed between sections of the first web side wall and the second web side wall, which are offset from each other in the extension direction of the at least one sealing web.

[0054] A further development of the bipolar plate can also provide that at least one sealing rib has a wave-like shape at least in sections along the direction of extension.

[0055] The undulating profile of the at least one sealing rib is formed particularly in the main plane of extension of the plate body. In a top view of the bipolar plate, the at least one undulating sealing rib preferably forms a plurality of troughs and crests along its direction of extension.

[0056] In a top view of the bipolar plate, the at least one wave-shaped sealing rib can preferably have a uniform or periodic shape along the direction of extension.

[0057] Between two adjacent vertices of the at least one wave-shaped sealing rib, the sealing rib can have either a straight course or a curved course.

[0058] One advantageous approach involves the first web sidewall having a wavy base line at a transition area to a base section of the panel body, and the wavelength of the wavy profile of the sealing web differing from the wavelength of the base line. This allows for even better adaptability of the sealing web's mechanical properties.

[0059] Another advantageous option involves the second web side wall having a wavy base line at a transition area to a base section of the panel body, and the wavelength of the wavy profile of the sealing web differing from the wavelength of the base line. This allows for even better adaptability of the mechanical properties of the sealing web.

[0060] One particularly advantageous option involves the first and second web side walls having a wavy base line at a transition area to a base section of the panel body, and the wavelength of the wavy profile of the sealing web differing from the wavelength of the base line. This allows for even better adaptability of the mechanical properties of the sealing web.

[0061] An advantageous solution involves using a cycle wavelength that differs from the wavelength of the wave-like profile of the sealing rib, based on the alternating shallow and steepening angles of inclination of the first rib sidewall. This allows for even better adaptability of the sealing rib's mechanical properties.

[0062] Another advantageous solution involves using a cycle wavelength for the cycles of alternating shallow and steepening inclination angles of the second web sidewall that differs from the wavelength of the wave-like profile of the sealing web. This allows for even better adaptability of the sealing web's mechanical properties.

[0063] A particularly advantageous solution involves differentiating the respective cycle wavelengths of the cycles with alternatingly shallow and steeper inclination angles of the first and second web side walls from the wavelength of the wave-like profile of the sealing web. This allows for even better adaptability of the mechanical properties of the sealing web.

[0064] A particularly advantageous application of the bipolar plate according to the invention is, according to a further development of the invention, an electrochemical unit comprising at least one membrane electrode unit and at least one bipolar plate, which is designed according to one of the embodiments described above.

[0065] The electrochemical unit is in particular a fuel cell unit or an electrolysis unit.

[0066] The fuel cell unit can be configured as any type of fuel cell comprising a multitude of such bipolar plates to form a fuel cell stack. For example, the fuel cell unit can be configured as a polymer electrolyte fuel cell (PMFC), alkaline fuel cell (AFC), direct methanol fuel cell (DMFC), or phosphoric acid fuel cell (PAFC).

[0067] In particular, the fuel cell unit comprises a plurality of membrane electrode assemblies stacked in a stacking direction to form a fuel cell stack, with the membrane electrode assemblies each arranged between the bipolar plates. Specifically, a bipolar plate is arranged on both the anode and cathode sides of the membrane electrode assembly.

[0068] The bipolar plates form an anode compartment on the anode side and a cathode compartment on the cathode side, through which the fluid medium (e.g. process gas) is supplied and / or removed for the fuel cell reaction.

[0069] In a fuel cell unit consisting of such bipolar plates, an optimized sealing effect can be achieved, leading to a significant reduction in leakage flows, particularly of a reaction medium or cooling medium, and thus to an optimized performance potential of the fuel cell unit. Consequently, the use of the bipolar plate can result in an improved efficiency of the fuel cell unit.

[0070] Further preferred features and / or advantages of the invention are the subject of the following description and the graphic representation of exemplary embodiments.

[0071] The drawings show:

[0072] Fig. 1 shows a schematic top view of a bipolar plate according to an embodiment as disclosed;

[0073] Fig. 2 is a schematic top view of a sealing rib of the bipolar plate according to detail II in Fig. 1;

[0074] Fig. 3 shows a schematic sectional view of the sealing web according to section III-III in

[0075] Fig. 2;

[0076] Fig. 4 shows a schematic sectional view of the sealing web according to section IV-IV in

[0077] Fig. 2;

[0078] Fig. 5 is a schematic top view of a sealing rib according to an alternative embodiment of the bipolar plate; Fig. 6 is a schematic sectional view of the sealing rib according to section Vl-Vl in

[0079] Fig. 5;

[0080] Fig. 7 shows a schematic sectional view of the sealing web according to section VII-VII in Fig. 5;

[0081] Fig. 8 shows a schematic top view of a sealing rib according to a further alternative embodiment of the bipolar plate; and

[0082] Fig. 9 shows a schematic top view of a sealing rib according to another alternative embodiment of the bipolar plate.

[0083] Fig. 1 shows a schematic top view of a bipolar plate designated as a whole by 100 according to an embodiment as disclosed for an electrochemical unit not shown in detail, in particular for a fuel cell unit or an electrolysis unit.

[0084] Such a fuel cell unit is formed by one or more fuel cell stacks, each comprising several fuel cells arranged in a stack. The fuel cell stacks are also referred to as fuel cell stacks, which comprise a plurality of such bipolar plates.

[0085] The fuel cell unit can be configured as any fuel cell unit comprising 100 bipolar plates to form the fuel cell stack, for example a polymer electrolyte fuel cell (PMFC), alkaline fuel cell (AFC), direct methanol fuel cell (DMFC) or phosphoric acid fuel cell (PAFC).

[0086] The fuel cell unit comprises a feed for supplying a fluid medium to the fuel cells, in particular a fuel, fuel mixture (fuel-exhaust gas mixture), oxidizer, and / or coolant. The exhaust gas, fuel, oxidizer, and / or coolant are discharged from the fuel cells via an exhaust port. The fuel cell unit comprises a plurality of membrane electrode assemblies (not shown in detail) arranged in a stacking direction between adjacent bipolar plates 100. That is, one bipolar plate 100 is arranged on one anode side and one cathode side of each membrane electrode assembly.

[0087] In other words, the bipolar plate 100 forms the anode side of one membrane electrode assembly and the cathode side of an adjacent membrane electrode assembly.

[0088] The bipolar plate 100 is designed to ensure a uniform distribution and supply of the fluid medium to the membrane electrode units as well as optimal drainage of the fluid medium.

[0089] The bipolar plate 100 can be formed from a plate body 102 or from several plate bodies 102, on which a flow field 104 for the fluid medium is formed.

[0090] Preferably the plate body 102 is made of metal.

[0091] The surface of the plate body 102 may be provided with a coating, in particular with a conductive and / or corrosion-resistant coating.

[0092] For example, the plate body 102 can be coated with gold, titanium, titanium nitride, carbon, chromium nitride and / or a ceramic material.

[0093] The flow field 104 is formed by a multitude of flow channels, not shown in detail, through which the fluid medium can flow.

[0094] The flow channels are preferably formed from the plate body 102; in particular, they are formed from, molded onto, or incorporated into the plate body 102. For supplying and discharging the fluid medium, one or more media inlets 106 and one or more media outlets 108 are formed on the plate body 102.

[0095] The media inlets 106 and media outlets 108 are also referred to as manifolds or headers and form channels running in the stacking direction (perpendicular to the image plane) through the stacked bipolar plates 100 for supplying and removing the fluid medium to and from the flow field 104.

[0096] A sealing rib 110 is formed on the plate body 102, which limits the flow field 104 at least sectionally to an edge region 112 of the bipolar plate 100.

[0097] This sealing rib 110 can form an edge rib of the bipolar plate 100.

[0098] The sealing rib 110 forms a fluid boundary of the flow field 104 to the edge region 112 of the bipolar plate 100.

[0099] In other words, the sealing rib 110 forms a boundary device to an outside.

[0100] Preferably the sealing rib 110 is designed as a groove, in particular a sealing groove.

[0101] Preferably the sealing rib 110 extends fully along the edge region 112 of the bipolar plate 100 and surrounds the flow field 104 as well as the media inlets 106 and media outlets 108.

[0102] In addition, further sealing webs 110 are formed on the plate body 102, each surrounding the media inlets 106 and the media outlets 108.

[0103] These additional sealing ribs 110 are provided to limit the media inlets 106 and the media outlets 108 to each other, to the flow field 104 and / or to the edge area 112 of the bipolar plate 100.

[0104] Although the following explanations are based on the sealing bridge 110, which surrounds the flow field 104 as well as the media inlets 106 and media outlets 108, the further sealing bridges 110, which each surround the media inlets 106 and the media outlets 108, can be designed equivalently.

[0105] Preferably the sealing webs 110 are formed from the plate body 102, in particular formed from it, molded onto it or inserted into it.

[0106] The sealing ribs 110 are preferably each designed as a groove, in particular a sealing groove on the plate body 102.

[0107] Such a groove is in particular formed from, molded onto or incorporated into the plate body 102.

[0108] In particular, such a groove is integrally formed from the plate body 102.

[0109] In the assembled state of the fuel cell unit, a plurality of bipolar plates 100 are stacked on top of each other, so that adjacent bipolar plates 100 are at least partially supported against each other via the sealing webs 110, preferably indirectly.

[0110] In this case, the sealing ribs 110 of adjacent bipolar plates 100 can be designed to be mirror-symmetrical to each other.

[0111] The sealing ribs 110 can form sealing sections 114 on their upper sides, which, in the assembled state of the fuel cell unit, preferably indirectly abut an adjacent bipolar plate 100 in a sealing manner.

[0112] The sealing webs 110, which limit the media inlets 106 and the media outlets 108, have flow passages 116, which are referred to as flow ports.

[0113] In the embodiment of the bipolar plate 100 shown in Fig. 1, the sealing rib 110 has a substantially straight course along its direction of extension E. Fig. 2 shows a schematic top view of the sealing rib 110 of the bipolar plate 100 according to Detail II in Fig. 1, and Figs. 3 and 4 each show schematic sectional views of the sealing rib 110 according to Section III-III and Section IV-IV in Fig. 2.

[0114] As shown in particular in the sectional views of the sealing web 110 according to Figs. 3 and 4, the sealing web 110 is formed by the top surface 114 as well as a first web side wall 118 and a second web side wall 120, which extend along the direction of extension E of the sealing web 110.

[0115] Preferably the top surface 114, the first web side wall 118 and the second web side wall 120 are formed from the plate body 102, in particular integrally formed.

[0116] The first web side wall 118 and the second web side wall 120 form opposite side walls of the sealing web 110 along the extension direction E of the sealing web 110.

[0117] In other words, the side walls of the web 118, 120 form lateral boundaries of the sealing web 110.

[0118] The first web side wall 118 and the second web side wall 120 have different angles of inclination along the extension direction E of the sealing web 110 with respect to a main extension plane 122 of the plate body 102.

[0119] Due to the different inclination angles of the first web side wall 118 and the second web side wall 120 along the extension direction E of the sealing web 110, a wavy base line 124 of the first and second web side walls 118, 120 results in Figs. 1 and 2.

[0120] The undulating base line 124 of the first and second web side walls 118, 120 forms a transition zone from the respective web side walls 118, 120 into a base section 126 of the plate body 102, which preferably lies in the main extension plane 122 of the plate body 102. Due to the different inclination angles of the first and second web side walls 118, 120, these have a plurality of sections along the extension direction E of the sealing web 110, which are inclined at different angles of inclination N, i.e., at shallower and steeper angles of inclination N, with respect to the main extension plane 122 of the plate body 102.

[0121] The inclination angles N of the first and second web side wall 118, 120 change along the extension direction E of the sealing web 110 between a maximum inclination angle 128 and a minimum inclination angle 130.

[0122] The sectional view of the sealing web 110 shown in Fig. 3 according to section III-III in Fig. 2 shows a section of the sealing web 110 in which the web side walls 118, 120 are inclined at the maximum angle of inclination 128.

[0123] The sectional view of the sealing web 110 shown in Fig. 4 according to section IV-IV in Fig. 2 shows a section of the sealing web 110 in which the web side walls 118, 120 are inclined at the minimum angle of inclination 130.

[0124] In the sections of the sealing web 110 between the maximum angle of inclination 128 and the minimum angle of inclination 130, the angle of inclination N of the first and second web side wall 118, 120 along the extension direction E of the sealing web 110 can have both a uniformly and a stepwise increasing angle of inclination N, i.e. increasing angle of inclination N, or a flatter angle of inclination N, i.e. decreasing angle of inclination N.

[0125] The minimum inclination angle 130 can be an angle of at least 10°, preferably at least 20°, more preferably at least 30°, with respect to the principal extension plane 122 of the plate body 102.

[0126] For example, the minimum inclination angle 130 can be an angle of approximately 30°, ± 20°, preferably ± 10°, with respect to the principal extension plane 122 of the plate body 102. The maximum inclination angle 128 can be an angle of at most 85°, preferably at most 80°, more preferably at most 70°, with respect to the principal extension plane 122 of the plate body 102.

[0127] For example, the maximum inclination angle 128 can be an angle of about 65°, + / - 20°, preferably + / - 10°, with respect to the principal extension plane 122 of the plate body 102.

[0128] An angle difference 132 between the maximum inclination angle 128 and the minimum inclination angle 130 can be at least 5°, preferably at least 10°, more preferably at least 15°, more preferably at least 20°.

[0129] In other words, the inclination angles N of the first web side wall 118 and inclination angles N of the second web side wall 120 can diverge from each other along the extension direction E of the sealing web 110 with an angle difference 132 of at least 5°, preferably at least 10°, more preferably at least 15°, more preferably at least 20°.

[0130] As shown by the wavy base line 124 in Fig. 2 and by the two sectional views according to Figs. 3 and 4, the first web side wall 118 and the second web side wall 120 have alternatingly shallower and steeper angles of inclination N along the extension direction E of the sealing web 110.

[0131] This means that the inclination angles N of the first and second web side wall 118, 120 along the extension direction E of the sealing web 110 are preferably formed in a uniformly or stepwise flatter and steeper manner.

[0132] Preferably, the inclination angles N of the first and second web side wall 118, 120 along the extension direction E of the sealing web 110 are cyclically, in particular periodically, becoming shallower and steeper.

[0133] In other words, the first and second web sidewalls 118, 120 are inclined along the extension direction E of the sealing web 110 in a constantly repeating inclination profile with increasingly steep and shallower angles of inclination N. It is particularly provided that the angles of inclination N of the first web sidewall 118 and the angles of inclination N of the second web sidewall 120 along the extension direction E of the sealing web 110, i.e., the inclination profile of the web sidewalls 118, 120, are in phase with each other.

[0134] In other words, opposing sections of the first web side wall 118 and the second web side wall 120 are inclined at essentially the same angles of inclination N, as shown in the sectional views according to Figs. 3 and 4.

[0135] This means that sections of the first web side wall 118 and the second web side wall 120, which are inclined at the same angles N, are each opposite each other.

[0136] Thus, the minimum inclination angles 130 of the first web side wall 118 are opposite to the minimum inclination angles 130 of the second web side wall 120, and the maximum inclination angles 128 of the first web side wall 118 are opposite to the maximum inclination angles 128 of the second web side wall 120.

[0137] The inclination angles N of the first web side wall 118 and inclination angles N of the second web side wall 120 therefore exhibit a periodically phase-matched inclination profile.

[0138] The phase-coherent inclination profile of the angles of inclination N of the first web side wall 118 and the angle of inclination N of the second web side wall 120 along a length E of the sealing web 110 exhibits a multitude of periodic cycles. This means an inclination profile with a multitude of periodically alternating, shallower and steeper angles of inclination of the first web side wall 118 and the second web side wall 120.

[0139] Preferably, the phase-coherent inclination profile of the inclination angle N of the first web side wall 118 and the inclination angle N of the second web side wall 120 over a length E of the sealing web 110 exhibits at least one cycle, preferably at least two cycles, more preferably at least five cycles, and more preferably at least ten cycles, of alternatingly shallow and steepening inclination angles N of the first web side wall 118 and the second web side wall 120. For example, the inclination profile of the first web side wall 118 and the second web side wall 120 over a length of the sealing web 110 of approximately 100 mm can exhibit at least one cycle, preferably at least two cycles, more preferably at least five cycles, and more preferably at least ten cycles, of alternatingly shallow and steepening inclination angles.

[0140] Fig. 5 shows a schematic top view of a sealing rib 110 according to an alternative embodiment of the bipolar plate 100.

[0141] The following section describes only the differences between the alternative embodiments of the bipolar plate 100 described above and the embodiment described above, and features that are not further described are to be understood as corresponding to the embodiment described above.

[0142] As in the previously described embodiment of the bipolar plate 100, the inclination angles N of the first and second web side wall 118, 120 along the extension direction E of the sealing web 110 are also cyclically, in particular periodically, becoming shallower and steeper in this alternative embodiment of the bipolar plate 100.

[0143] This means that the first and second side walls of the web 118, 120 are inclined along the extension direction E of the sealing web 110 in a constantly repeating inclination profile at increasingly steep and shallower angles of inclination N.

[0144] However, in this alternative embodiment of the bipolar plate 100, the inclination angles N of the first web side wall 118 and the inclination angles N of the second web side wall 120 are phase-shifted relative to each other along the extension direction E of the sealing web 110.

[0145] In other words, opposing sections of the first web side wall 118 and the second web side wall 120 are inclined at different angles N, as shown in the sectional views of Figs. 6 and 7 according to sections V1-V1 and V7-V7 in Fig. 5. The minimum angles of inclination 130 of the first web side wall 118 are opposite the maximum angles of inclination 128 of the second web side wall 120, and vice versa.

[0146] Thus, the inclination angles N of the first web side wall 118 and inclination angles N of the second web side wall 120 exhibit a periodically phase-shifted inclination profile.

[0147] It is preferably provided that at least between the opposing maximum and minimum inclination angles 128, 130 of the web side walls 118, 120 an angle difference of at least 5°, preferably at least 10°, further preferably at least 15°, further preferably at least 20°, is formed.

[0148] Alternatively, the inclination angles N of the first web side wall 118 and the inclination angles N of the second web side wall 120 along the extension direction E of the sealing web 110 can also be phase-shifted relative to each other by any other phase shift.

[0149] In the sections of the sealing web 110 between the maximum and minimum inclination angles 128, 130, the inclination angle N of the first and second web side wall 118, 120 along the extension direction E of the sealing web 110 can have both a uniformly and a stepwise increasing inclination angle N, i.e., increasing inclination angle N, or a flatter inclination angle N, i.e., decreasing inclination angle N.

[0150] Figures 8 and 9 each show further alternative embodiments of the bipolar plate 100, in which the sealing rib 110 has a wave-like profile along the extension direction E, wherein this wave-like profile of the sealing rib 110 is formed in the main extension plane 122 of the plate body 102, i.e. in the image plane of Figures 8 and 9.

[0151] Alternatively, the sealing rib 110 can also have any other curved, angular, zigzag, or similar shape. The sealing rib 110 can have such a wavy, curved, angular, zigzag, or similar shape either over its entire length or only in sections.

[0152] In the wave-shaped sealing rib 110 according to the embodiment in Fig. 8, the inclination angles N of the first rib side wall 118 and the inclination angles N of the second rib side wall 120 along the extension direction E of the sealing rib 110 are in phase with each other, as previously described with regard to the embodiment of the bipolar plate 100 according to Fig. 2.

[0153] This means that, in the embodiment of the bipolar plate 100 according to Fig. 8, opposing sections of the first web side wall 118 and the second web side wall 120 are inclined at essentially the same angles of inclination N, as is shown in the sectional views according to Figs. 3 and 4. Deviations arise only because the undulating shape of the sealing web 110 also influences the angles of inclination N.

[0154] Thus, preferably the locally minimum inclination angles 130 of the first web side wall 118 are approximately opposite to the locally minimum inclination angles 130 of the second web side wall 120, and the locally maximum inclination angles 128 of the first web side wall 118 are approximately opposite to the locally maximum inclination angles 128 of the second web side wall 120.

[0155] The inclination angles N of the first web side wall 118 and inclination angles N of the second web side wall 120 therefore exhibit a periodically approximately phase-matched inclination profile.

[0156] In the corrugated sealing rib 110 according to the embodiment shown in Fig. 9, the angles of inclination N of the first rib side wall 118 and the angles of inclination N of the second rib side wall 120 are phase-shifted relative to each other along the extension direction E of the sealing rib 110, as previously described with regard to the embodiment of the bipolar plate 100 according to Fig. 5. That is, in the embodiment of the bipolar plate 100 according to Fig. 9, opposing sections of the first rib side wall 118 and the second rib side wall 120 are inclined at different angles of inclination N, as is shown in the sectional views according to Figs. 6 and 7. The only deviations are that the corrugated shape of the sealing rib 110 also influences the angles of inclination N.

[0157] Thus, the locally minimum inclination angles 130 of the first web side wall 118 are approximately opposite to the locally maximum inclination angles 128 of the second web side wall 120, and the locally maximum inclination angles 128 of the first web side wall 118 are approximately opposite to the locally minimum inclination angles 130 of the second web side wall 120.

[0158] The inclination angles N of the first web side wall 118 and inclination angles N of the second web side wall 120 consequently exhibit a periodically phase-shifted inclination profile along the extension direction E of the sealing web 110, whereby the inclination angles N can also be phase-shifted relative to each other by any phase shift.

[0159] Reference symbol list 00 Bipolar plate

[0160] 102 plates body

[0161] 104 Flow field

[0162] 106 Media feed

[0163] 108 Media Discharge

[0164] 110 sealing strip

[0165] 112 Edge area

[0166] 114 Top

[0167] 116 Flow passage

[0168] 118 first side wall of the bridge

[0169] 120 second side wall of the bridge

[0170] 122 Main extent level

[0171] 124 Base line

[0172] 126 Basic section

[0173] 128 maximum tilt angle

[0174] 130 minimum tilt angle

[0175] 132 Angle difference E Direction of extension

Claims

Patent claims 1. Bipolar plate (100) for an electrochemical unit, comprising at least one plate body (102) on which: - a multitude of flow channels are provided which form at least one flow field (104) for a fluid medium, - at least one media feed (106) for feeding and / or at least one media discharge (108) for discharging the fluid medium is provided, - at least one sealing rib (110) is provided which limits the flow field (104), the at least one media inlet (106) and / or the at least one media outlet (108) at least sectionally and which has a first rib side wall (118) and a second rib side wall (120), wherein - at least one of the web side walls (118, 120) has different angles of inclination (N) at least section by section with respect to a principal extension plane (122) of the plate body (102) and / or the web side walls (118, 120) have different angles of inclination (N) at least section by section.

2. Bipolar plate according to claim 1, characterized in that at least one of the web side walls (118, 120) is inclined along a direction of extension (E) of the sealing web (110) at different angles of inclination (N) and / or the web side walls (118, 120) are inclined at least sectionally at different angles of inclination (N) along the direction of extension (E) of the sealing web (110).

3. Bipolar plate according to claim 1 or 2, characterized in that the inclination angles (N) of the first web side wall (118) and / or the second web side wall (120) along the extension direction (E) of the sealing web (110) have an alternatingly shallower and steeper inclination profile, preferably a cyclically shallower and steeper inclination profile.

4. Bipolar plate according to one of the preceding claims, characterized in that the inclination angles (N) of the first web side wall (118) and the inclination angles (N) of the second web side wall (120) along the The direction of extension (E) of the sealing web (110) shall have an inclination profile that is at least in phase with each other in sections and / or at least in phase with each other in sections.

5. Bipolar plate according to claim 3 or 4, characterized in that along an extension length of the at least one sealing rib (110) at least one cycle, preferably at least two cycles, more preferably at least five cycles, more preferably at least ten cycles, of alternatingly shallower and steeper inclination angles (N) of the first rib side wall (118) and / or the second rib side wall (120) is provided.

6. Bipolar plate according to one of the preceding claims, characterized in that the various inclination angles (N) of the first web side wall (118) and / or the second web side wall (120) with respect to the main extension plane (122) of the plate body (102) are inclined between a minimum inclination angle (130) of at least 10°, preferably at least 20°, more preferably at least 30°, and / or a maximum inclination angle (128) of at most 85°, preferably at most 80°, more preferably at most 70°.

7. Bipolar plate according to one of the preceding claims, characterized in that an angle difference (132) of at least 5°, preferably at least 10°, more preferably at least 15°, more preferably at least 20°, is provided between a minimum inclination angle (130) and a maximum inclination angle (128) of the first web side wall (118) and / or the second web side wall (120).

8. Bipolar plate according to one of the preceding claims, characterized in that an angle difference of at least 5°, preferably at least 10°, further preferably at least 15°, further preferably at least 20°, is provided at least sectionally between the inclination angles (N) of the first web side wall (118) and the second web side wall (120).

9. Bipolar plate according to one of the preceding claims, characterized in that the at least one sealing rib (110) has a wave-like profile at least section by section along the direction of extension (E).

10. Bipolar plate according to claim 9, characterized in that the first web side wall (118) and / or the second web side wall (120) have a wavy base line (124) at a transition area to a base section (126) of the plate body (102), and that a wavelength of the wavy course of the sealing web (110) differs from a wavelength of the base line (124).

11. Bipolar plate according to claim 9 or 10, characterized in that a cycle wavelength of the cycles of alternatingly shallow and steepening inclination angles (N) of the first rib side wall (118) and / or the second rib side wall (120) differs from a wavelength of the wave-like progression of the sealing rib (110).

12. Electrochemical unit comprising at least one membrane electrode unit and at least one bipolar plate (100) according to any one of claims 1 to 11.

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