Electrochemical device and method for manufacturing an electrochemical device

Description

[0001] The present invention relates to an electrochemical device comprising several electrochemical units arranged in a stacking direction, wherein each electrochemical unit comprises a bipolar plate and an electrically insulating seal, and wherein the electrochemical device comprises a clamping device for pressing the electrochemical units together in the stacking direction.

[0002] In known electrochemical devices of this type, there is an increased risk of electrical short circuits between the bipolar plates of successive electrochemical units at the outer surface of the stack formed by the electrochemical units and / or at the boundary surfaces of medium channels through which the fluid media required for the operation of the electrochemical device are supplied to the electrochemical units, because the outer and inner edge regions of the bipolar plates are freely accessible. Such an electrical short circuit can be caused, for example, by the inclusion of dirt or other foreign particles and / or by contaminated, especially non-deionized, water.

[0003] The additional application of electrically insulating layers in the outer and inner edge areas of the bipolar plates requires a high level of effort in the manufacturing process and can lead to restrictions in the process flow, especially in the manufacturing processes of the individual components of the electrochemical device, particularly when the outer contours and / or the inner contours of the bipolar plates are formed from more than one layer.

[0004] CN 104 538 654 A and US 2012 / 237847 A1 disclose electrochemical devices comprising several electrochemical units arranged in a stacking direction, each electrochemical unit comprising a bipolar plate and an electrically insulating seal, and a clamping device for pressing the electrochemical units together in the stacking direction, wherein at least one seal of at least one electrochemical unit, when pressed, projects laterally in a direction perpendicular to the stacking direction beyond a contour of the bipolar plate of the electrochemical unit.

[0005] CN 108 054 407 A discloses an electrochemical device according to the preamble of claim 1.

[0006] EP 1 633 011 A1 discloses an electrochemical device comprising several electrochemical units arranged in a stacking direction, each electrochemical unit comprising two separator plates and an electrically insulating seal, and a clamping device for pressing the electrochemical units together in the stacking direction, wherein all seals of the electrochemical units, when pressed, project laterally in a direction perpendicular to the stacking direction beyond a contour of the respective associated separator plate.

[0007] The present invention is based on the objective of creating an electrochemical device of the type mentioned above in which the risk of a short circuit between adjacent bipolar plates is reduced without excessively increasing the effort required to manufacture the electrochemical device.

[0008] This problem is solved by an electrochemical device according to claim 1.

[0009] The present invention is therefore based on the concept of using the seals, which are already required to separate the various media spaces of the electrochemical device from each other and / or from the environment of the electrochemical device, in addition to shielding the bipolar plates at least partially on their outer contours from the environment of the electrochemical device and / or on their inner contours from the medium channels penetrating the electrochemical device, in order to prevent electrically conductive elements, for example dirt or other foreign particles or contaminated, in particular non-deionized, water, from entering the area between the bipolar plates and causing a short circuit between adjacent bipolar plates.

[0010] The contour beyond which the at least one seal of at least one electrochemical unit projects laterally in a direction perpendicular to the stacking direction in the compressed state can be an outer contour or an inner contour of the bipolar plate.

[0011] The seal can extend laterally beyond the contour over part of the circumference of the relevant contour of the bipolar plate or over the entire circumference of the relevant contour of the bipolar plate.

[0012] In a particular embodiment of the invention, it is provided that at least one seal of at least one electrochemical unit, in the compressed state, protrudes beyond an outer contour of the bipolar plate of the electrochemical unit into an outer space of the electrochemical device.

[0013] Alternatively or additionally, it may be provided that at least one seal of at least one electrochemical unit, in the compressed state, protrudes beyond an inner contour of the bipolar plate of the electrochemical unit into a medium channel of the electrochemical device.

[0014] It is particularly preferred if at least one seal of at least one electrochemical unit, in the compressed state, projects both over an outer contour of the bipolar plate of the electrochemical unit into an outer space of the electrochemical device and also over an inner contour of the bipolar plate of the electrochemical unit into at least one medium channel of the electrochemical device.

[0015] Preferably, at least one seal of at least one electrochemical unit rests against a seal of an adjacent electrochemical unit in the compressed state.

[0016] At least one outer contour of at least one bipolar plate is shielded from an external space of the electrochemical device by at least one seal adjacent to the bipolar plate, preferably substantially completely and / or preferably over substantially the entire circumference of the outer contour of the bipolar plate in question.

[0017] Furthermore, it is advantageous if at least one inner contour of at least one bipolar plate is shielded from a medium channel of the electrochemical device by at least one seal adjacent to the bipolar plate, preferably substantially completely and / or preferably over substantially the entire circumference of the respective inner contour of the respective bipolar plate.

[0018] In a particular embodiment of the invention, it is provided that the seal, in the uncompressed state, does not project laterally beyond the contour of the bipolar plate in a direction perpendicular to the stacking direction, either over a part of the circumference of the relevant contour of the respective bipolar plate or over the entire circumference of the relevant contour of the respective bipolar plate.

[0019] The seal rests with at least one contact area against two adjacent bipolar plates of the electrochemical device.

[0020] In a particular embodiment of the invention, the contact area is asymmetrically shaped in the uncompressed state with respect to a longitudinal plane of the seal, which runs parallel to the stacking direction and parallel to a longitudinal direction of the seal through a crest of the contact area. Such an asymmetrical shape of the contact area can promote the tendency of the contact area, during the compression of the electrochemical units of the electrochemical device, to move towards and / or beyond the outer or inner contour of an adjacent bipolar plate.

[0021] The seal can include an insulating area which, in the compressed state, rests against an insulating area of ​​another seal of the electrochemical device.

[0022] The seal may have one or more wedge-shaped areas.

[0023] In a preferred embodiment of the invention, it is provided that the outer surfaces of the seals of the electrochemical device form a closed outer sealing surface on an outer side of the electrochemical device when pressed.

[0024] In particular, it may be provided that the outer sealing surface surrounds the electrochemical device along its entire circumference.

[0025] Furthermore, it is advantageous if the inner surfaces of the seals of the electrochemical device, when compressed, form a closed inner sealing surface on an inner side of the electrochemical device adjacent to a medium channel of the electrochemical device.

[0026] It is particularly advantageous if such a closed inner sealing surface surrounds the relevant medium channel along its entire circumference.

[0027] The present invention further relates to a method for manufacturing an electrochemical device, which comprises the following: Formation of a stack comprising several successive electrochemical units along a stacking direction, each electrochemical unit comprising a bipolar plate and an electrically insulating seal; and clamping of the stack of electrochemical units by means of a clamping device.

[0028] The present invention is based on the further objective of providing a method of the aforementioned type by which an electrochemical device is produced in which the risk of a short circuit between adjacent bipolar plates in the stack of electrochemical units is reduced, without excessively increasing the effort required to produce the electrochemical device.

[0029] This problem is solved by a method according to claim 12.

[0030] In particular, it may be provided that at least one seal of at least one electrochemical unit does not (yet) protrude laterally beyond the relevant contour of the bipolar plate in a direction perpendicular to the stacking direction in the unpressed state.

[0031] The inventive method for producing an electrochemical device is particularly suitable for producing an electrochemical device according to the invention.

[0032] Specific embodiments of the inventive method for producing an electrochemical device have already been explained above in connection with specific embodiments of the inventive electrochemical device.

[0033] The electrochemical device according to the invention can in particular be a fuel cell device, an electrolyzer or a battery stack.

[0034] A fluid medium required for the operation of the electrochemical device, for example an anode gas, a cathode gas or a cooling medium, can be supplied to or removed from the electrochemical units of the electrochemical device via a medium channel of the electrochemical device.

[0035] The medium channel preferably extends substantially parallel to the stacking direction of the electrochemical device.

[0036] According to the invention, at least one seal is designed such that, after the assembly of the stack of electrochemical units and after the clamping of the stack along the stacking direction, it projects laterally over at least one bipolar plate adjacent to the seal in a projection direction perpendicular to the stacking direction of the stack.

[0037] The seals of the electrochemical device can be designed in particular such that, in the compressed state of the electrochemical device, they completely enclose the outer surfaces of the stack, so that no bipolar plates of the electrochemical device are visible from the outside of the electrochemical device.

[0038] The overhang of the seal in the overhang direction perpendicular to the stacking direction, extending laterally beyond at least one adjacent bipolar plate, can already exist before the stack of electrochemical units is clamped, or it can only be generated during the clamping of the stack of electrochemical units by a movement of at least one part of the seal.

[0039] In the pressed state of the electrochemical units, the outer contours and / or the inner contours of the bipolar plates are reliably isolated from each other and from external influences, so that short circuits between the bipolar plates are structurally excluded.

[0040] In particular, it prevents the bipolar plates from being contacted on their outer circumference by electrically conductive foreign particles and / or by electrically conductive, especially non-deionized, water, thus preventing the formation of short circuits.

[0041] The contours of the bipolar plates protected by the seals can be located both in the area of ​​the outer surfaces of the stack of electrochemical units and in the area of ​​inner surfaces of the stack of electrochemical units, in particular in the area of ​​the inner surfaces of the stack facing a medium channel of the electrochemical device.

[0042] If it is intended that the seal moves along the stacking direction in a direction perpendicular to the stacking direction during the compression of the stack of electrochemical units, so that the overhang of the seal over an adjacent bipolar plate is only reached during the compression of the stack, this can be advantageous for assembling the stack of electrochemical units, since in this case it is possible to guide the electrochemical units to each other via the outer edges of the bipolar plates when stacking them on top of each other.

[0043] The seal of each electrochemical unit of the electrochemical device can be a single piece or consist of two or more sealing parts.

[0044] Movement of the seal perpendicular to the stacking direction during the compression of the stack of electrochemical units can be achieved by the geometric shape of the seal or by the geometric shape of one or more of the bipolar plates adjacent to the seal.

[0045] The material properties and / or the geometry of the seal or at least one of the bipolar plates adjacent to the seal can be influenced in such a way that the coefficients of friction between the seal and the at least one adjacent bipolar plate are selectively reduced or increased locally, in such a way that the movement of the seal during the compression of the stack of electrochemical units perpendicular to the stack direction is promoted.

[0046] In particular, it may be provided that the seal and / or at least one of the bipolar plates adjacent to the seal are treated by plasma treatment, by treatment with a primer and / or by treatment with a lubricant in such a way that the coefficient of friction between the seal and the at least one adjacent bipolar plate is locally changed.

[0047] Alternatively or additionally, the coefficient of friction between the seal and the at least one adjacent bipolar plate can be achieved by geometrically structuring the seal and / or the bipolar plate in question and / or by deliberately creating a smooth surface on the seal and / or on the at least one bipolar plate.

[0048] The seal is made of an elastomer material.

[0049] The seal can be manufactured, for example, by an injection molding process, by a pattern printing process, in particular a screen printing process, or by a bead application process.

[0050] The seal can be attached to an adjacent bipolar plate, a gas diffusion layer, a component of a membrane electrode arrangement of the electrochemical unit and / or another support element.

[0051] The bipolar plates can be made from one or more metallic materials.

[0052] Each bipolar plate can be single-layered or multi-layered.

[0053] The electrochemical units of the electrochemical device preferably comprise a polymer electrolyte membrane (PEM).

[0054] It is particularly advantageous if the seals of the electrochemical device enclose the outer contours of the bipolar plates of the electrochemical device, at least after the stack of electrochemical units has been compressed, in such a way that electrical insulation protection is ensured.

[0055] The seal can be inserted into the electrochemical unit as a separate component or be materially bonded to the bipolar plate of the electrochemical unit, or to a component of the membrane electrode assembly (MEA), or to a porous gas diffusion layer of the electrochemical unit.

[0056] Further advantages and features of the invention are the subject of the following description and the graphic representation of exemplary embodiments.

[0057] The drawings show: Fig. 1 is a schematic representation of an electrochemical device comprising several electrochemical units arranged in a stacking direction and a clamping device for pressing the electrochemical units together along the stacking direction, wherein each electrochemical unit comprises a bipolar plate and an electrically insulating seal, and wherein the seals of the electrochemical units, when pressed, project laterally beyond a contour of the bipolar plates of the electrochemical units in a direction perpendicular to the stacking direction; Fig. 2 is a schematic top view of one of the bipolar plates of the electrochemical device. Fig. 1 ; Fig. 3 shows a partial cross-section through the electrochemical device made of Fig. 1 in the area of ​​an outer contour or an inner contour of the bipolar plates, in a compressed state of the seals after clamping the electrochemical units by means of the clamping device; Fig. 4 one of the Fig. 3 corresponding partial cross-section through the electrochemical device made of Fig. 1 in the area of ​​an outer contour or an inner contour of the bipolar plates, in an uncompressed state of the seals, before pressing the electrochemical units by means of the clamping device; Fig. 5 a partial cross-section through a second embodiment of the electrochemical device, in which the seals comprise a wedge-shaped area, in a compressed state of the seals, after pressing the electrochemical units by means of the clamping device; Fig. 6 a partial cross-section through a third embodiment of the electrochemical device, in which the seals do not project laterally beyond an outer contour or an inner contour of the bipolar plates in the uncompressed state, in the uncompressed state of the seals, before pressing the electrochemical units by means of the clamping device; Fig.Fig. 7 a partial cross-section through a fourth embodiment of the electrochemical device, in which the seals each comprise a wedge-shaped area, a symmetrically designed contact area and an insulating area, in an uncompressed state of the seals, before the electrochemical units are compressed by means of the clamping device; Fig. 8 a partial cross-section through a fifth embodiment of the electrochemical device, in which the seals have a wedge-shaped area, an asymmetrical contact area and an insulating area, in an uncompressed state of the seals, before the electrochemical units are compressed by means of the clamping device; Fig.Fig. 9 a partial cross-section through a sixth embodiment of the electrochemical device, in which the seals have a wedge-shaped region, in an uncompressed state of the seals, before the electrochemical units are compressed by means of the clamping device; and Fig. 10 a partial cross-section through a seventh embodiment of the electrochemical device, in which the seals have a wedge-shaped region and a contact area which is asymmetrical with respect to a plane oriented parallel to the stacking direction, in an uncompressed state of the seals, before the electrochemical units are compressed by means of the clamping device.

[0058] Identical or functionally equivalent elements are designated with the same reference symbols in all figures.

[0059] One in the Fig. 1 bis 4 The electrochemical device shown, designated as a whole by 100, is designed, for example, as a fuel cell device or as an electrolyzer.

[0060] The electrochemical device 100 comprises a stack 102, which includes several electrochemical units 104 that follow one another along a stacking direction 106.

[0061] Each of the electrochemical units 104 comprises a bipolar plate 108 and an electrically insulating seal 110 as well as an (not shown) electrochemically active unit in which an electrochemical reaction takes place between electrochemically reactive species which originate from the fluid reaction media supplied to the electrochemical device 100, in particular an anode gas and a cathode gas.

[0062] In the Fig. 1 In the pressed state shown, the electrochemical units 104 of the electrochemical device 100 are clamped along the stacking direction 106 by means of a clamping device 112, which comprises end plates 114, between which the stack 102 of electrochemical units 104 is arranged.

[0063] The end plates 114 can be braced against each other in any way, for example by means of tie rods.

[0064] Each of the bipolar plates 108 shows how best to Fig. 2 As can be seen, an outer contour 116 and several inner contours 118 surround a medium passage opening 120 of the bipolar plate 108.

[0065] Each of the medium passage openings 120 forms a component of a respective assigned medium channel 122, which penetrates the stack 102 of electrochemical units 104 parallel to the stack direction 106.

[0066] The medium channels 122 serve to supply fluid media to the electrochemical units 104 or to remove fluid media from the electrochemical units 104.

[0067] In particular, it may be provided that each of the medium channels 122 is designed as an anode gas supply channel 124, as a cathode gas supply channel 126, as a cooling medium supply channel 128, as an anode gas discharge channel 130, as a cathode gas discharge channel 132 or as a cooling medium discharge channel 134.

[0068] Each bipolar plate 108 has a flow field for each of these fluid media, through which the fluid medium can flow from the respective associated supply channel to the respective associated discharge channel, along a flow direction that is essentially perpendicular to the stacking direction 106.

[0069] In particular, the bipolar plate 108 can have an anode gas flow field through which the anode gas can flow from the anode gas supply channel 124 to the anode gas discharge channel 130.

[0070] Furthermore, the bipolar plate 108 can have a cathode gas flow field through which the cathode gas can flow from the cathode gas supply channel 126 to the cathode gas discharge channel 132.

[0071] Furthermore, the bipolar plate 108 can have a cooling medium flow field through which the cooling medium can flow from the cooling medium supply channel 128 to the cooling medium discharge channel 134.

[0072] How best to Fig. 1 As can be seen, the bipolar plates 108 of the electrochemical units 104 are electrically isolated from each other by the electrically insulating seals 110 arranged between each pair of bipolar plates 108, so that no short circuit occurs in the electrochemical device 100.

[0073] In the Fig. 1 In the depicted compressed state of the electrochemical units 104, the seals 110 protrude laterally beyond the outer contour 116 of the bipolar plate 108 of the same electrochemical unit 104 in a direction 136 perpendicular to the stacking direction 106.

[0074] In principle, it can be provided that the seals 110 each project over only a part of their circumference beyond the outer contour 116 of the respective associated bipolar plate 108 in the projection direction 136; preferably, however, it is provided that the seals 110 project over their entire circumference and over the entire circumference of the outer contour 116 of the respective associated bipolar plate 108 in the projection direction 136 beyond the respective associated bipolar plate 108.

[0075] The seals 110, with their insulating areas 138 projecting beyond the respective associated bipolar plate 108, abut the seals 110 above and below them in the stacking direction 106, so that the outer surfaces 140 of the seals 110 together form a closed outer sealing surface 142 on the outside of the electrochemical device 100.

[0076] Through this closed outer sealing surface 142, the outer contours 116 of the bipolar plates 108 of the electrochemical units 104 are completely shielded from an outer space 144 of the electrochemical device 100, so that no conductive elements, in particular no dirt, no foreign particles and / or no contaminated, for example non-deionized, water, can contact the bipolar plates 108 from the outer space 144 of the electrochemical device 100.

[0077] A short circuit between two bipolar plates 108 following one another in the stacking direction 106 due to contamination by such electrically conductive elements from the outside space 144 of the electrochemical device 100 is thereby excluded.

[0078] Furthermore, it may be provided that in the Fig. 1 In the compressed state of the electrochemical units 104 shown, the seals 110 project laterally in the overhang direction 136 perpendicular to the stacking direction 106 beyond at least one of the inner contours 118, which each surround a medium passage opening 120 of a medium channel 122 of the electrochemical device 100, of the bipolar plate 108 of the same electrochemical unit 104.

[0079] Both the outer contours 116 of the bipolar plates 108 and the inner contours 118 of the bipolar plates 108 thus form contours 119 of the bipolar plates 108, over which the seals 110 can project laterally in a projection direction 136 perpendicular to the stacking direction 106 when pressed.

[0080] In principle, it can be provided that the seals 110 each project over only a part of their circumference beyond the respective inner contour 118 of the respective associated bipolar plate 108 in the projection direction 136; preferably, however, it is provided that the seals 110 project over their entire inner circumference and over the entire circumference of the respective inner contour 118 of the respective associated bipolar plate 108 in the projection direction 136 beyond the respective associated bipolar plate 108.

[0081] The seals 110 also lie with insulating areas 138 projecting beyond the respective associated bipolar plate 108 against the seals 110 above and below them in the stacking direction 106, so that the inner surfaces 140' of the seals 110 together form a closed inner sealing surface 142' on the inside of the electrochemical device 100 and on the outer circumference of the respective associated medium channel 122.

[0082] Through this closed inner sealing surface 142', the inner contours 118 of the bipolar plates 108 of the electrochemical units 104 are completely shielded from the respective associated medium channel 122, so that no conductive elements, in particular no dirt, no foreign particles and / or no contaminated, for example non-deionized, water, can contact the bipolar plates 108 from the interior 144' of the respective associated medium channel 122.

[0083] A short circuit between two bipolar plates 108 following one another in the stacking direction 106 due to contamination by such electrically conductive elements from the interior 144' of a medium channel 122 of the electrochemical device 100 is thereby excluded.

[0084] As from Fig. 4 As can be seen, which shows a partial cross-section through the electrochemical device 100 in the area of ​​an outer contour 116 or in the area of ​​an inner contour 118 of the bipolar plates 108, the bipolar plates 108 can each have a groove 146 in the area in which the seals 110 seal against the bipolar plates 108.

[0085] The seals 110 each have one or more contact areas 148 with which the seals 110 each bear against an adjacent bipolar plate 108 or against several adjacent bipolar plates 108.

[0086] For example, each seal 110 can have a first contact area 150 with which the seal abuts the bead of the bipolar plate 108 of the same electrochemical unit 104, and a second contact area 152 with which the seal 110 abuts the bipolar plate 108 of the same electrochemical unit 104 and, on a sealing surface opposite this bipolar plate 108, a bipolar plate 108 of an adjacent electrochemical unit 104.

[0087] An insulating area 138 of the seal 110 adjoins the contact area 148 or the contact areas 148 of the seal 110, which is arranged on the side of the contact area 148 or the contact areas 148 of the seals 110 facing the outer space 144 of the electrochemical device 100 or the interior 144' of a medium channel 122 of the electrochemical device 100.

[0088] On the side of the contact area 148 or contact areas 148 facing away from the insulation area 138, a connection area 156 of the seal 110 is arranged, via which the seal 110 can be connected, for example, to the (not shown) electrochemically active unit of the respective electrochemical unit 104 and / or to a gas diffusion layer of the electrochemical unit 104.

[0089] As from Fig. 4 As can be seen, which represents the unpressed state of the seals 110 before the electrochemical units 104 are pressed by means of the clamping device 112, the seals 110 with their insulating areas 138 already protrude laterally in the overhang direction 136 into the outer space 144 or into the interior space 144' of a medium channel 122 of the electrochemical device 100 in the unpressed state of the seals 110 beyond the outer contours 116 or the inner contours 118 of the bipolar plates 108.

[0090] However, the insulation areas 138 of the seals 110 touch in the Fig. 4 The unpressed state of the seals 110 shown is not yet shown.

[0091] In the Fig. 3 In the pressed state of the seals 110 shown, after pressing the electrochemical units 104 by means of the clamping device 112, the seals 110 contact each other, so that the closed outer sealing surface 142 is formed on the outside of the electrochemical device 100 or the closed inner sealing surface 142' is formed on a medium channel 122 of the electrochemical device 100.

[0092] One in Fig. 5 The second embodiment of an electrochemical device 100 shown differs from the one described in the Fig. 1 bis 4 The first embodiment shown is distinguished by the fact that the seals 110 have only one contact area 148 which abuts two adjacent bipolar plates 108, and a wedge-shaped area 158 of the seals 110 is arranged on the side of the contact area 148 facing away from the insulation area 138.

[0093] In this wedge-shaped area 158, the thickness of the respective seals 110 increases, that is, their extension along the stacking direction 106, with decreasing distance from the insulation area 138.

[0094] In this embodiment, the wedge-shaped area 158, the contact area 148 and the insulation area 138 of the seals 110 are essentially symmetrical to a central plane 160 of the seals 110, which, in the assembled state of the electrochemical device 100, runs perpendicular to the stacking direction 106 through the respective seal 110 at half the height of the respective seal 110.

[0095] Fig. 5 shows the seals 110 in the unpressed state, before pressing the electrochemical units 104 by means of the clamping device 112.

[0096] Out of Fig. 5 It can be seen that in this embodiment the seals 110 already project laterally beyond the outer contour 116 or beyond the inner contour 118 of the bipolar plates 108 along the overhang direction 136 in the unpressed state and that the insulation areas 138 already touch in the unpressed state of the seals 110.

[0097] By pressing the electrochemical units 104 together using the clamping device 112, the contact areas 148 and the insulation areas 138 arranged thereon are moved even further into the outer space 144 of the electrochemical device 100 or into the interior 144' of the medium channel 122.

[0098] Moreover, the in Fig. 5 The second embodiment of an electrochemical device 100, as illustrated, differs in terms of structure, function and method of manufacture from that described in the Fig. 1 bis 4 the first embodiment shown, to the foregoing description of which reference is made.

[0099] One in Fig. 6 The third embodiment of an electrochemical device 100, shown in partial detail, differs from the one in Fig. 5 the second embodiment shown, in that the seals 110 are in the Fig. 6 The seals 110 are shown in their unpressed state before the electrochemical units 104 are pressed using the clamping device 112, and do not yet protrude laterally in the overhang direction 136 beyond the outer contour 116 or the inner contour 118 of the bipolar plates 108.

[0100] During the compression of the electrochemical units 104, however, the seals 110 move in the overhang direction 136 so far that the overhang of the seals 110 is reached over the outer contour 116 or over the inner contour 118 of the bipolar plates 108 during the compression of the stack 102 of electrochemical units 104.

[0101] In the (not shown) compressed state of the seals 110, the insulation areas 138 of successive seals 110 along the stacking direction 106 are in contact with each other, so that in this embodiment a closed outer sealing surface 142 or a closed inner sealing surface 142' is formed.

[0102] Furthermore, in this embodiment, the insulation areas 138 of the seals 110 are made so thick in the stacking direction 106 that, after the compression of the electrochemical units 104 by means of the clamping device 112, they have contact with both bipolar plates 108 adjacent to the respective seal 110.

[0103] Moreover, the in Fig. 6 The third embodiment of an electrochemical device 100, as illustrated, is comparable in terms of structure, function and method of manufacture to the one described in Fig. 5 the second embodiment shown, to the foregoing description of which reference is made.

[0104] One in Fig. 7 The fourth embodiment of an electrochemical device 100, shown in partial detail, differs from the one in Fig. 6 The third embodiment shown is distinguished in that the seals 110 in this embodiment have two wedge-shaped areas 158 and 158', between which a contact area 148 of the respective seal 110 is arranged, which is formed essentially symmetrically to a longitudinal plane 162 of the seal 110. The longitudinal plane 162 extends parallel to the outer surface 140 or 140' of the respective seal 110 and parallel to the stacking direction 106 as well as through the crests 163 of the contact area 148, with which the contact area 148 abuts one of the adjacent bipolar plates 108.

[0105] In the second wedge-shaped area 158' of the seal 110, the thickness of the seal 110, i.e. its extent along the stacking direction 106, decreases with decreasing distance from the insulation area 138 of the seal 110.

[0106] In this embodiment, the insulating area 138 of the seal 110 is designed such that, after the assembly of the stack 102 but before the compression of the electrochemical units 104 by means of the clamping device 112, it does not come into contact with the adjacent bipolar plates 108.

[0107] However, when the electrochemical units are pressed together, the insulation area 138 is moved beyond the outer contour 116 or the inner contour 118 of the bipolar plates 108 by the movement of the insulation area 138 caused by the volume displacement of the contact area 148 and the wedge-shaped areas 158 and 158'.

[0108] In the pressed state of the seals 110, the insulating areas 138 of seals 110 following one another in the stacking direction 106 contact each other, and a closed outer sealing surface 142 or a closed inner sealing surface 142' is formed, which shields the bipolar plates 108 from the outer space 144 of the electrochemical device 100 or from the inner space 144' of a medium channel 122 of the electrochemical device 100.

[0109] In this case, the outer edges of the bipolar plates 108 are preferably completely enclosed by the sealing material of the seals 110.

[0110] Moreover, the in Fig. 7 The fourth embodiment of an electrochemical device 100, as illustrated, is comparable in terms of structure, function and method of manufacture to the one described in Fig. 6 the third embodiment shown, to the foregoing description of which reference is made.

[0111] One in Fig. 8 The fifth embodiment of an electrochemical device 100, shown in partial detail, differs from the one in Fig. 7 The fourth embodiment shown is characterized by the fact that the second wedge-shaped area 158' of the seals 110 is omitted and the contact area 148 of the sealing elements 110 is asymmetrical with respect to the longitudinal plane 162 of the seals 110 running through the domes 163 of the contact area 148.

[0112] In particular, the contact area 148 is designed such that its flank 164 facing the insulation area 138 forms a smaller angle with the stacking direction 106 than its flank 166 facing away from the insulation area 138.

[0113] In particular, it can be provided that the flank 164 of the contact area 148 facing the insulation area 138 is oriented essentially parallel to the stacking direction 106.

[0114] This asymmetrical design of the contact area 148 of the seals 110 promotes movement of the sealing material from the area between the bipolar plates 108 out into the outer space 144 of the electrochemical device 100 or into the interior 144' of the medium channel 122 when the electrochemical units 104 are pressed together by means of the clamping device 112.

[0115] Moreover, the in Fig. 8 The fifth embodiment of the electrochemical device 100, as illustrated, differs in its construction, function, and method of manufacture from that shown in Fig. 7 the fourth embodiment shown, to the foregoing description of which reference is made.

[0116] One in Fig. 9 The sixth embodiment of an electrochemical device 100, shown in partial detail, differs from the one in Fig. 8 The fifth embodiment is characterized in that the seals 110 do not have a separate insulating area 138 in addition to the contact area 148, which is arranged on a side of the contact area 148 facing the outer space 144 or the inner space 144' of the medium channel 122, but instead the contact area 148 itself also assumes the function of an insulating area 138, with which the seals 110, in the pressed state of the seals 110, after the electrochemical units 104 have been pressed by means of the clamping device 112, abut each other in order to form a closed outer sealing surface 142 or a closed inner sealing surface 142'.

[0117] The contact area 148 is dimensioned such that, during the pressing of the electrochemical units 104, it moves completely or at least partially beyond the outer contour 116 or beyond the inner contour 118 of the bipolar plates 108 along the overhang direction 136.

[0118] In the Fig. 9 In the unpressed state of the seals 110 shown, the contact area 148 lies completely against the two adjacent bipolar plates 108.

[0119] Moreover, the in Fig. 9 The sixth embodiment of the electrochemical device 100 shown here, with regard to its structure, function and method of manufacture, is comparable to the one described in Fig. 8 the fifth embodiment shown, to the foregoing description of which reference is made.

[0120] One in Fig. 10 The seventh embodiment of an electrochemical device 100, shown in partial detail, differs from the one in Fig. 9 The sixth embodiment shown is characterized by the fact that the seals 110 are asymmetrical with respect to the central plane 160 of the respective seal 110, which runs perpendicular to the stacking direction 106 through the respective seal 110 at half the height of the respective seal 110.

[0121] In particular, it can be provided that the contact area 148, which also takes on the function of an insulating area 138, the wedge-shaped area 158 and the connection area 156 are in, preferably planar, contact with the bipolar plate 108 of the same electrochemical unit 104.

[0122] The seals 110 are preferably materially bonded to the bipolar plate 108 of the respective electrochemical unit 104.

[0123] In particular, it may be provided that the seals are produced by an injection molding process, a pattern printing process, in particular a screen printing process, or by a dispenser application process. in situ are generated on the respective assigned bipolar plate 18.

[0124] The bipolar plates 108 can each be formed in one piece or comprise several, preferably two or more, layers of bipolar plates.

[0125] The contact area 148 of the seals 110 is designed such that, during the compression of the electrochemical units 104 by means of the clamping device 112, it moves along the overhang direction 136 over the outer contour 116 or the inner contour 118 of the bipolar plates 108 into the outer space 144 of the electrochemical device 100 or into the interior 144' of the medium channel 122.

[0126] Moreover, the in Fig. 10 The seventh embodiment of the electrochemical device 100, as illustrated, is comparable in terms of structure, function and method of manufacture to the one described in Fig. 9the sixth embodiment shown, to whose preceding description reference is made.

[0127] The seals 110 described above can each be connected to a bipolar plate 108 or to several bipolar plates 108, to a gas diffusion layer or to several gas diffusion layers, to a part of an electrochemically active unit, in particular a membrane electrode arrangement, and / or to another support element.

[0128] The seals 110 are made of an elastomer material.

[0129] The bipolar plates 108 are preferably made of a metallic material.

[0130] The bipolar plates 108 can each be formed in one piece and comprise only a single bipolar plate layer, or they can comprise several, in particular two or more, bipolar plate layers.

Claims

1. Electrochemical device, comprising a plurality of electrochemical units (104), which succeed one another along a stack direction (106), wherein each electrochemical unit (104) comprises a bipolar plate (108) and an electrically insulating seal (110), and a clamping device (112) for pressing together the electrochemical units (104) along the stack direction (106), wherein at least one seal (110) of at least one electrochemical unit (104), in the pressed state, protrudes laterally beyond a contour (119) of the bipolar plate (108) of the electrochemical unit (104) in a direction of protrusion (136) directed perpendicularly to the stack direction (106), and wherein at least one outer contour (116) of at least one bipolar plate (108) is shielded from an outside space (144) of the electrochemical device (100) by at least one seal (110) adjacent to the bipolar plate (108), characterized in that the at least one seal (110) is made of an elastomer material, and in that the seal (110), in the unpressed state and / or in the pressed state, abuts with at least one contact region (148) against two adjacent bipolar plates (108) of the electrochemical device (100).

2. Electrochemical device in accordance with Claim 1, characterized in that at least one seal (110) of at least one electrochemical unit (104), in the pressed state, protrudes beyond an outer contour (116) of the bipolar plate (108) of the electrochemical unit (104) into an outside space (144) of the electrochemical device (100).

3. Electrochemical device in accordance with either of Claims 1 or 2, characterized in that at least one seal (110) of at least one electrochemical unit (104), in the pressed state, protrudes beyond an inner contour (118) of the bipolar plate (108) of the electrochemical unit (104) into a medium channel (122) of the electrochemical device (100).

4. Electrochemical device in accordance with any one of Claims 1 to 3, characterized in that at least one seal (110) of at least one electrochemical unit (104), in the pressed state, abuts against a seal (110) of an adjacent electrochemical unit (104).

5. Electrochemical device in accordance with any one of Claims 1 to 4, characterized in that at least one inner contour (118) of at least one bipolar plate (108) is shielded from a medium channel (122) of the electrochemical device (100) by at least one seal (110) adjacent to the bipolar plate (108).

6. Electrochemical device in accordance with any one of Claims 1 to 5, characterized in that the seal (110), in the unpressed state, does not protrude laterally beyond the contour (119) of the bipolar plate (108) in a direction of protrusion (136) directed perpendicularly to the stack direction (106).

7. Electrochemical device in accordance with any one of Claims 1 to 6, characterized in that the contact region (148), in the unpressed state, is of asymmetrical configuration in relation to a longitudinal plane (162) of the seal (110), which extends in parallel to the stack direction (106) and in parallel to a longitudinal direction of the seal (110) through a crest (163) of the contact region (148).

8. Electrochemical device in accordance with any one of Claims 1 to 7, characterized in that the seal (110) comprises an insulating region (138), which, in the pressed state, abuts against an insulating region (138) of a further seal (110) of the electrochemical device (100).

9. Electrochemical device in accordance with any one of Claims 1 to 8, characterized in that the seal (110) has at least one wedge-shaped region (158, 158').

10. Electrochemical device in accordance with any one of Claims 1 to 9, characterized in that the outer faces (140) of the seals (110) of the electrochemical device (100), in the pressed state, form a closed outer sealing face (142) on an outer side of the electrochemical device (100).

11. Electrochemical device in accordance with any one of Claims 1 to 10, characterized in that the inner faces (140') of the seals (110) of the electrochemical device (100), in the pressed state, form a closed inner sealing face (142') on an inner side of the electrochemical device (100) adjoining a medium channel (122) of the electrochemical device (100).

12. Method for producing an electrochemical device (100), comprising the following: - forming a stack (102), which comprises a plurality of electrochemical units (104) succeeding one another along a stack direction (106), wherein each electrochemical unit (104) comprises a bipolar plate (108) and an electrically insulating seal (110); and - clamping the stack (102) of electrochemical units (104) by means of a clamping device (112); wherein at least one seal (110) of at least one electrochemical unit (104), in the pressed state, protrudes laterally beyond a contour (119) of the bipolar plate (108) of the electrochemical unit (104) in a direction of protrusion (136) directed perpendicularly to the stack direction (106), and wherein at least one outer contour (116) of at least one bipolar plate (108) is shielded from an outside space (144) of the electrochemical device (100) by at least one seal (110) adjacent to the bipolar plate (108), characterized in that the at least one seal (110) is made of an elastomer material, and in that the seal (110), in the unpressed state and / or in the pressed state, abuts with at least one contact region (148) against two adjacent bipolar plates (108) of the electrochemical device (100).

13. Method in accordance with Claim 12, characterized in that at least one seal (110) of at least one electrochemical unit (104), in the unpressed state, does not protrude laterally beyond the contour (119) of the bipolar plate (108) in a direction of protrusion (136) directed perpendicularly to the stack direction (106).