Electrochemical device

Abstract

In order to create an electrochemical device comprising a plurality of electrochemical units that follow one another along a stacking direction and each comprise a sealing arrangement, wherein each sealing arrangement comprises at least one coolant duct seal surrounding a coolant duct and at least one reactant duct seal surrounding a reactant duct, wherein the coolant duct seal and the reactant duct seal are formed at least partially from an elastomer material, a thermoplastic material and / or a thermosetting material, wherein permeation of low-molecular compounds from the coolant through the sealing arrangement into at least one reactant duct of the electrochemical device is reduced or entirely prevented, the invention proposes that the coolant duct seal and the reactant duct seal are separated from one another by an interruption region or are formed integrally with one another via a thinning region, wherein a maximum extent of the thinning region along the stacking direction of the electrochemical device is less than 25% of a maximum extent of the coolant duct seal and / or of a maximum extent of the reactant duct seal along the stacking direction of the electrochemical device.

Description

[0001] Electrochemical device

[0002] The present invention relates to an electrochemical device comprising a plurality of electrochemical units arranged successively along a stacking direction, wherein the electrochemical units each comprise a sealing arrangement, wherein the sealing arrangement each comprises at least one coolant channel seal surrounding a coolant channel and at least one reactant channel seal surrounding a reactant channel, and wherein the coolant channel seal and the reactant channel seal are formed at least partially from an elastomer material, a thermoplastic material and / or a thermoset material.

[0003] Such electrochemical devices are known in particular in the form of fuel cell devices, in particular polymer electrolyte membrane fuel cell devices.

[0004] The reactants of a fuel cell device are the cathode gas, in particular an oxidizer, and the anode gas, which contains hydrogen as fuel gas.

[0005] In the area of ​​the channels that supply the coolant and reactants of the electrochemical device to the electrochemical units or that discharge the coolant and spent reactants from the electrochemical units of the electrochemical device (these areas are also referred to as "manifolds"), the aforementioned polymeric sealing materials come into contact with both the reactants and the coolant. This direct contact with the reactants and the coolant can cause both physical and chemical changes to the polymeric sealing materials. An important physical mechanism at play here is the swelling of polymer material due to the diffusion of low-molecular-weight compounds into the polymer matrix of an elastomer material, a thermoplastic material, or a thermoset material.In particular, the coolant contains such low-molecular compounds, which can lead to swelling of the polymer materials mentioned.

[0006] Due to the swellability of the polymer material of the sealing arrangement, the coolant is able to diffuse into the material of the sealing arrangement, overcome the sealing barrier and finally penetrate into the reactant supply of the electrochemical device.

[0007] Penetration of the coolant into the reactant channels results in contamination of the reactants and thus possible failure of the electrochemical device.

[0008] In addition, the penetration of the coolant into the polymer matrix of the sealing arrangement material leads to a reorientation of polymer chains, which expands the polymer matrix in such a way that further swelling and thus permeation of the coolant into the reactant channels is additionally promoted.

[0009] The present invention is based on the object of creating an electrochemical device of the type mentioned above, in which permeation of low-molecular compounds from the coolant through the sealing arrangement into at least one reactant channel of the electrochemical device is reduced or completely prevented.

[0010] This object is achieved according to the invention in an electrochemical device having the features of the preamble of claim 1 in that the coolant channel seal and the reactant channel seal are separated from one another by an interruption region or are formed integrally with one another via a thinning region, wherein a maximum extent h of the thinning region along the stacking direction of the electrochemical device is less than 25% of a maximum extent H of the coolant channel seal along the stacking direction of the electrochemical device and / or a maximum extent H of the reactant channel seal along the stacking direction of the electrochemical device.

[0011] It is advantageous if the thinning area is made of the same material as the coolant channel seal and the reactant channel seal.

[0012] The thinning region is preferably formed as a single piece with the coolant channel seal and the reactant channel seal.

[0013] Preferably, the maximum dimensions of the thinning region, the coolant channel seal and the reactant channel seal along the stacking direction are compared with each other in a relaxed initial state of these seals before the electrochemical units of the electrochemical device are clamped against each other along the stacking direction.

[0014] The present invention is based on the concept that the geometry of the sealing arrangement is structurally interrupted or thinned in the area between the sealing lips of the coolant channel seal on the one hand and the reactant channel seal on the other. These measures prevent or at least impede permeation of the coolant through the sealing arrangement into the at least one reactant channel of the electrochemical device.

[0015] The space between the coolant channel seal and the reactant channel seal, which are structurally separated from each other, or the sealing gap created by the thinning of the area of ​​the sealing arrangement between the coolant channel seal and the reactant channel seal is used as a drainage channel to drain the coolant to the outside of the respective electrochemical unit and thus to the outside of the electrochemical device.

[0016] Preferably, the sealing arrangement in the manifold region of the electrochemical device is interrupted between the reactant channels at both the inlet and the outlet to the manifold of the coolant circuit.

[0017] By interrupting or thinning the sealing arrangement in the manifold area of ​​the electrochemical device, cross-contamination of the reactants of the electrochemical device by the coolant due to permeation of the coolant through the sealing arrangement is prevented or at least made more difficult.

[0018] In a preferred embodiment of the invention, it is provided that the maximum extent h of the thinning region along the stacking direction of the electrochemical device is less than 10% of the maximum extent H of the coolant channel seal along the stacking direction of the electrochemical device and / or less than 10% of the maximum extent H of the reactant channel seal along the stacking direction of the electrochemical device.

[0019] The at least one thinning region or interruption region of the sealing arrangement is preferably arranged between a sealing lip of the coolant channel seal and a sealing lip of the reactant channel seal.

[0020] It is particularly advantageous if the at least one thinned-out region or interrupted region of the sealing arrangement is arranged between the sealing lip of the coolant channel seal closest to the reactant channel seal and the sealing lip of the reactant channel seal closest to the coolant channel seal. Due to the structural interruption or thinning of the sealing arrangement between the coolant channel seal and each reactant channel seal, the problem can arise that the sealing arrangement becomes problematic during handling, particularly during assembly of the electrochemical device, because the coolant channel seal and the reactant channel seals are very flexible if they are not connected to one another by a sufficiently strong connecting region.This can result in the sealing arrangement having to be laboriously positioned and maintained in shape during assembly of the electrochemical device.

[0021] In a particular embodiment of the invention, it is therefore provided that the sealing arrangement comprises a frame to which at least one coolant channel seal and / or at least one reactant channel seal of the sealing arrangement is connected, wherein the frame is formed from a different frame than the coolant channel seal and is formed from a different material than the reactant channel seal.

[0022] Preferably, the frame is formed from a material which has a higher flexural stability than the material from which the coolant channel seal and the reactant channel seal are formed.

[0023] For example, it can be provided that the frame comprises a polyphenylene sulfide material and / or a polyphthalamide material.

[0024] Furthermore, to increase the flexural rigidity of the frame, it is advantageous if the frame material contains at least 10% by weight of glass fibers.

[0025] Preferably, the material of the frame contains at least 20% by weight, in particular at least 30% by weight, particularly preferably at least 40% by weight, for example at least 50% by weight, of glass fibers. In a preferred embodiment of the invention, the frame is not in contact with the coolant and / or not in contact with any of the reactants of the electrochemical device during normal operation of the electrochemical device.

[0026] It is particularly advantageous if, during normal operation of the electrochemical device, the frame is not in contact with the coolant or with any of the reactants (anode gas or cathode gas) of the electrochemical device.

[0027] In this case, the frame does not have to meet the high resistance requirements with regard to the coolant and the reactants, which the material from which the coolant channel seal and the reactant channel seals of the sealing arrangement are formed must meet.

[0028] The frame should preferably be manufactured without distortion.

[0029] The frame is connected to the coolant channel seal and to the at least one reactant channel seal preferably by material connection, by frictional connection and / or by positive connection.

[0030] For example, it can be provided that the frame is manufactured separately before the coolant channel seal and the reactant channel seals and is placed in an injection mold, in which the coolant channel seal and the reactant channel seals are then formed from an injection-moldable material and are integrally connected to the frame, in particular injection-molded onto the frame.

[0031] In order to avoid permeation of coolant molecules through the frame into the at least one reactant channel, it is preferably provided that the solubility of the coolant in the material of the frame at a temperature of 20°C is less than one mass percent, in particular less than one per mille by mass. Furthermore, in order to avoid permeation of coolant molecules through the frame into the at least one reactant channel, it is advantageous if the diffusion coefficient of the coolant in the material of the frame at a temperature of 20°C is less than 1 ■ 10' 12 m 2 / s.

[0032] In a preferred embodiment of the invention, it is provided that the frame comprises at least one spacer region which extends into a space between a coolant channel seal and a reactant channel seal of the sealing arrangement or into a space between two reactant channel seals of the sealing arrangement.

[0033] This at least one spacer area further increases the mechanical stability of the sealing arrangement.

[0034] In addition, the risk of short circuits between bipolar plates adjacent to the sealing arrangement is reduced over the operating life of the electrochemical device in the area between the coolant channel seal and the reactant channel seal of the sealing arrangement or in the area between the two reactant channel seals of the sealing arrangement.

[0035] Preferably, the at least one spacer region extends to a flow field seal of the sealing arrangement, which extends around a flow field of a bipolar plate of the electrochemical unit.

[0036] This flow field of the bipolar plate can be, for example, an anode gas flow field or a cathode flow field.

[0037] Preferably, the frame comprises at least two spacer regions, each extending into a gap between the coolant channel seal and a reactant channel seal of the sealing arrangement. In a particularly preferred embodiment of the invention, the frame extends completely around a coolant channel seal and / or around a reactant channel seal and / or around at least two reactant channel seals of the sealing arrangement.

[0038] Since the frame has only a low solubility for the coolant and a low diffusion coefficient for the coolant, this ensures that permeation of coolant from the coolant channel into the flow fields of the electrochemical unit, in particular into an anode gas flow field or a cathode gas flow field, is excluded or at least reduced.

[0039] It is particularly advantageous if the frame of the sealing arrangement extends completely around the coolant channel seal and all reactant channel seals, each individually, in a closed ring shape.

[0040] In addition, it can be provided that the frame extends around at least one flow field seal of the sealing arrangement.

[0041] The flow field seal in question may in particular extend around a cathode gas flow field of the electrochemical unit or around an anode gas flow field of the electrochemical unit.

[0042] If the sealing arrangement comprises at least one flow field seal which extends around a flow field of a bipolar plate of the electrochemical unit, it is advantageous if the coolant channel seal and / or at least one reactant channel seal of the sealing arrangement is separated from the flow field seal by an interruption region and / or if the coolant channel seal and / or at least one reactant channel seal of the sealing arrangement is integrally connected to the flow field seal of the sealing arrangement via a thinning region.Preferably, the sealing arrangement comprises a flow field seal which extends around a flow field of a bipolar plate of the electrochemical unit, wherein the flow field seal is integrally connected to the coolant channel seal and to the at least one of the at least one reactant channel seal via a connection region which is formed from the same polymer material as the flow field seal, the coolant channel seal and at least one of the at least one reactant channel seal.

[0043] The connection region is preferably formed in one piece with the flow field seal, with the coolant channel seal and with at least one of the at least one reactant channel seal.

[0044] The electrochemical device according to the invention is preferably designed as a fuel cell device, in particular a polymer electrolyte membrane fuel cell device.

[0045] Further features and advantages of the invention are the subject of the following description and the drawings illustrating exemplary embodiments. The drawings show:

[0046] Fig. 1 shows a schematic cross section through a sealing arrangement of an electrochemical unit of an electrochemical device comprising a plurality of electrochemical units arranged successively along a stacking direction, wherein the sealing arrangement comprises a coolant channel seal surrounding a coolant channel and a reactant channel seal surrounding a reactant channel, wherein the coolant channel seal and the reactant channel seal are formed at least partially from a polymer material and wherein the coolant channel seal and the reactant channel seal are formed integrally with one another, so that coolant molecules can pass from the coolant channel into the reactant channel by permeation through the polymer material of the coolant channel seal and the reactant channel seal;

[0047] Fig. 2 shows a schematic cross-section through the sealing arrangement and the adjacent bipolar plates from Fig. 1, wherein the material of the coolant channel seal and the material of the reactant channel seal have swollen during operation of the electrochemical device due to the penetration of the coolant, which further promotes the permeation of the coolant into the reactant channel;

[0048] Fig. 3 is a schematic plan view of an end region of a sealing arrangement of an electrochemical unit of an electrochemical device comprising a plurality of electrochemical units arranged successively along a stacking direction, wherein the end region of the sealing arrangement comprises a coolant channel seal, two reactant channel seals and a section of a flow field seal, viewed in the direction of the stacking direction of the electrochemical device;

[0049] Fig. 4 is a schematic cross-sectional view of the coolant channel seal and the reactant channel seal of the seal assembly of Fig. 3, wherein the coolant channel seal and the reactant channel seal are separated from each other by an interruption region to prevent permeation of coolant through the seal assembly from the coolant channel to the reactant channel, taken along line 4-4 in Fig. 3;

[0050] Fig. 5 shows a schematic cross section corresponding to Fig. 4 through the coolant channel seal and the reactant channel seal of the sealing arrangement from Fig. 3 in an alternative embodiment in which the coolant channel seal and the reactant channel seal are formed integrally with one another over a thinned-out region;

[0051] Fig. 6 is a schematic plan view of an end region of a further embodiment of a sealing arrangement of an electrochemical unit of an electrochemical device comprising a plurality of electrochemical units arranged successively along a stacking direction, wherein the sealing arrangement comprises a frame to which the coolant channel seal and the reactant channel seals of the end region of the sealing arrangement are connected, wherein the frame is formed from a material in which the coolant dissolves less well and / or in which the coolant diffuses more slowly than in the material of the coolant channel seal and / or in the material of the reactant channel seal;

[0052] Fig. 7 is a schematic plan view corresponding to Fig. 6 of an end region of a further embodiment of a sealing arrangement, wherein the frame comprises two spacer regions which extend into a space between the coolant channel seal and the first reactant channel seal and into a space between the coolant channel seal and the second reactant channel seal, respectively; and

[0053] Fig. 8 is a schematic plan view corresponding to Figs. 6 and 7 of the end region of a further embodiment of a sealing arrangement, wherein the frame extends completely around the coolant channel seal and around both reactant channel seals and / or a flow field seal extending around a flow field of a bipolar plate adjacent to the sealing arrangement is connected to the frame.

[0054] Identical or functionally equivalent elements are designated by the same reference numerals in all figures.

[0055] A sealing arrangement 100 of an electrochemical unit 102 of an electrochemical device 104, which is shown in detail in a cross-section in Fig. 1 and comprises a plurality of electrochemical units 102 arranged successively along a stacking direction 106, comprises a coolant channel seal 110 surrounding a coolant channel 108 of the electrochemical device 104 and a reactant channel seal 114 surrounding a reactant channel 112 of the electrochemical device 104.

[0056] The coolant channel 108 of the electrochemical device 104 extends along the stacking direction 106 through the electrochemical device 104.

[0057] Likewise, the reactant channel 112 of the electrochemical device 104 extends along the stacking direction 106 through the electrochemical device 104.

[0058] A reactant gas of the electrochemical device 104 is guided in the reactant channel 112, for example an anode gas (which preferably contains hydrogen) or a cathode gas (which preferably contains an oxidizing agent).

[0059] The coolant channel seal 110 and the reactant channel seal 114 seal a sealing gap 116 located between the coolant channel 108 and the reactant channel 112, which is arranged between a bipolar plate 118 of the electrochemical unit 102 and a bipolar plate 118' of a second electrochemical unit 102' following the first electrochemical unit 102 in the stacking direction 106.

[0060] Each of the bipolar plates 118, 118' is preferably formed in two layers and comprises a first bipolar plate layer 120 and a second bipolar plate layer 122, which are connected to one another by means of joining lines (not shown), preferably welding lines, in particular laser welding lines.

[0061] The coolant channel seal 110 comprises one or more, for example two, sealing lips 124, which sealingly bear against the bipolar plate 118 of the electrochemical unit 102 and extend in a closed ring around the coolant channel 108.

[0062] Furthermore, the coolant channel seal 110 comprises one or more, for example two, sealing lips 124', which sealingly bear against the bipolar plate 118' of the adjacent electrochemical unit 102 and extend in a closed ring around the coolant channel 108.

[0063] The reactant channel seal 114 comprises one or more, for example two, sealing lips 126, which sealingly bear against the bipolar plate 118 and extend in a closed ring around the reactant channel 112.

[0064] Furthermore, the reactant channel seal 114 comprises one or more, for example two, sealing lips 126', which rest against the bipolar plate 118' of the adjacent electrochemical unit 102 and extend in a closed ring around the reactant channel 112.

[0065] The coolant channel seal 110 and the reactant channel seal 114 are formed from a polymer material, preferably an elastomer material. Furthermore, the coolant channel seal 110 and the reactant channel seal 114 are formed integrally with one another, with a connecting region 128 of the sealing arrangement 100 arranged between the coolant channel seal 110 and the reactant channel seal 114 integrally connecting the coolant channel seal 110 and the reactant channel seal 114.

[0066] During operation of the electrochemical device 104, the coolant channel 108 is filled with coolant and the reactant channel 112 is filled with a reactant gas, i.e. with an anode gas or a cathode gas.

[0067] Low-molecular-weight coolant molecules 130, schematically represented by circles in Fig. 1, can permeate through the polymer material of the coolant channel seal 110 into the polymer material of the connecting region 128, from the polymer material of the connecting region 128 into the polymer material of the reactant channel seal 114, and from the polymer material of the reactant channel seal 114 into the reactant channel 112. The permeation direction of the coolant molecules 130 is indicated schematically in Fig. 1 by the arrows 132.

[0068] The permeation of the coolant molecules 130 into the polymer matrix of the polymer material of the sealing assembly 100 allows the coolant from the coolant channel 108 to first diffuse into the material of the sealing assembly 100, overcome the sealing barrier, and finally penetrate into the reactant channel 112 of the electrochemical device 104.

[0069] The penetration of the coolant into the reactant supply of the electrochemical device 104 results in contamination of the reactant gas, which can lead to failure of the electrochemical device 104. As the coolant penetrates the polymer matrix of the material of the sealing assembly 100, polymer chains of the polymer material reorient and the polymer matrix expands, causing further swelling and promoting further permeation of the coolant into the reactant channel 112.

[0070] The swelling of the polymer material of the sealing arrangement 100 due to the permeation of coolant molecules 130 into the polymer matrix of the sealing arrangement 100 is shown schematically in Fig. 2.

[0071] In order to avoid the problems caused by cross-contamination of the reactant gas by diffusing in the coolant, the second embodiment of a sealing arrangement 100 of an electrochemical unit 102 of an electrochemical device 104 shown in Figs. 3 and 4 provides that the coolant channel seal 110 of the sealing arrangement 100 is separated from the adjacent reactant channel seal 114 by an interruption region 134 (see Fig. 4).

[0072] According to Fig. 3, which shows a schematic plan view of an end region of the sealing assembly 100, the end region of the sealing assembly 100 comprises a coolant channel seal 110 and two reactant channel seals 114, namely a cathode gas channel seal 136 and an anode gas channel seal 138, and a portion of a flow field seal 140.

[0073] The coolant channel seal 110 extends around a coolant channel 108 of the electrochemical device 104, wherein the coolant channel 108 extends through a coolant passage opening 142 of a bipolar plate 118 along the stacking direction 106. The cathode gas channel seal 136 extends around a cathode gas channel 144 of the electrochemical device 104, wherein the cathode gas channel 144 extends along the stacking direction 106 through a cathode gas passage opening 146 in the bipolar plate 118.

[0074] The anode gas channel seal 138 extends around an anode gas channel 148 of the electrochemical device 104, wherein the anode gas channel 148 extends along the stacking direction 106 through an anode gas passage opening 150 in the bipolar plate 118.

[0075] The flow field seal 140 of the sealing arrangement 100 extends in a closed ring around a flow field 152 which is formed on the bipolar plate 118.

[0076] The flow field 152 may, for example, be an anode gas flow field or a cathode gas flow field.

[0077] The flow field seal 140 is preferably formed from the same polymer material, in particular from an elastomer material, as the coolant channel seal 110, the cathode gas channel seal 136 and the anode gas channel seal 138 of the seal assembly 100.

[0078] In the embodiment illustrated in Figs. 3 and 4, the flow field seal 140 is integrally connected to the coolant channel seal 110, the cathode gas channel seal 136, and the anode gas channel seal 138 via a connection region 154, which is also formed from the same polymer material as the flow field seal 140, the coolant channel seal 110, the cathode gas channel seal 136, and the anode gas channel seal 138. Preferably, the flow field seal 140, the coolant channel seal 110, the cathode gas channel seal 136, and the anode gas channel seal 138 are formed integrally with one another via the connection region 154.

[0079] In the embodiment shown in the drawing, the coolant channel 108 is arranged between the cathode gas channel 144 and the anode gas channel 148 of the electrochemical device 104.

[0080] In principle, however, each of the media channels can assume any position in the end region of the electrochemical unit 102; in particular, the coolant channel 108 can also be arranged in a corner of the electrochemical unit 102, in which case only one of the reactant channels 112 is arranged adjacent to the coolant channel 108.

[0081] As can be seen from the partial cross-section through the sealing arrangement 100 in Fig. 4, which shows the region of the sealing arrangement 100 between the coolant channel 108 and the cathode gas channel 144, the coolant channel seal 110 and the cathode gas channel seal 136 are structurally separated from one another in the interruption region 134.

[0082] Due to this interruption of the diffusion path, permeation of the coolant from the coolant channel 108 through the coolant channel seal 110 and the cathode gas channel seal 136 into the cathode gas channel 144 is no longer possible.

[0083] As can be seen from the top view in Fig. 3, the interruption region 134, which is formed between the coolant channel seal 110 and the cathode gas channel seal 136, extends to an outer edge 156 of the sealing arrangement 100. The interruption region 134 thus serves as a drainage for discharging the coolant diffused through the coolant channel seal 110 to the outside of the electrochemical unit 102 and thus of the electrochemical device 104. Due to this drainage effect, the concentration of the coolant in the interruption region 134 decreases so greatly that essentially no more coolant diffuses into the cathode gas channel seal 136 and from there into the cathode gas channel 144.

[0084] This means that the cathode gas is not contaminated by the coolant.

[0085] A corresponding interruption region 134 is provided between the coolant channel seal 110 on the one hand and the anode gas channel seal 138 on the other hand.

[0086] In addition, such interruption regions 134 are also provided between the coolant channel seal 110 and one of the reactant channel seals 114 in the further end region of the electrochemical unit 102 opposite the end region of Fig. 3. Regardless of which of the media channels is used to supply medium to the electrochemical unit 102 and which of the media channels is used to remove medium from the electrochemical unit 102, contamination of the reactant gases by the coolant is thus prevented, both from the coolant channel 108 supplying the coolant to the electrochemical unit 102 and from the coolant channel 108 removing the coolant from the electrochemical unit 102.

[0087] A third embodiment of a sealing arrangement 100 of an electrochemical unit 102 of an electrochemical device 102 shown in Fig. 5 differs from the second embodiment shown in Figs. 3 and 4 in that the connection between the coolant channel seal 108 and the reactant channel seal 114, for example the cathode gas channel seal 136, is not completely interrupted, but instead the coolant channel seal 110 is formed integrally with the reactant channel seal 114, for example with the cathode gas channel seal 136, via a thinned-out region 158. In this case, a maximum extent h of the thinning region 158 along the stacking direction 106 is less than 25% of a maximum extent H of the coolant channel seal 110 and / or less than 25% of a maximum extent H of the reactant channel seal 114 along the stacking direction 106 of the electrochemical device 104.

[0088] It is particularly favorable if the maximum extent h of the thinning region 158 along the stacking direction 106 is less than 10% of the maximum extent H of the coolant channel seal 110 and less than 10% of the maximum extent H of the reactant channel seal 114 along the stacking direction 106.

[0089] This significant reduction in the permeable cross-section of the thinned-out region 158 compared to the cross-section of the connecting region 128 of the first embodiment of a sealing arrangement 100 shown in Fig. 1 also ensures that a large proportion of the coolant diffused into the coolant channel seal 110 does not diffuse into the reactant channel seal 114, but is discharged via the drainage channels 160 located above or below the thinned-out region 158 along the stacking direction 106. The drainage channels 160, like the interruption region 134 of the first embodiment of a sealing arrangement 100 shown in Fig.3 and 4, at the outer edge 156 of the sealing arrangement 100, so that the coolant is drained through these drainage channels 160 from the area between the coolant channel seal 110 and the reactant channel seal 114 and is thereby prevented from diffusing into the reactant channel seal 114.

[0090] Preferably, the thinned-out region 158 is formed from the same material as the coolant channel seal 110 and the reactant channel seal 114. It is particularly advantageous if the thinned-out region 158 is formed integrally with the coolant channel seal 110 and the reactant channel seal 114.

[0091] Otherwise, the third embodiment of a sealing arrangement 100 of an electrochemical unit 102 of an electrochemical device 104 shown in Fig. 5 corresponds in terms of structure, function and method of manufacture to the second embodiment shown in Figs. 3 and 4, to the above description of which reference is made in this respect.

[0092] In the second embodiment of a sealing arrangement 100 shown in Figs. 3 and 4, the problem may arise that the sealing arrangement 100 becomes problematic in handling, in particular during assembly of the electrochemical device 104, because the coolant channel seal 110 and the reactant channel seals 114 are very flexible if they are not connected to one another by a sufficiently strong connecting region 128, which means that the sealing arrangement 100 must be laboriously positioned and held in shape during assembly of the electrochemical device 104.

[0093] A fourth embodiment of a sealing arrangement 100 of an electrochemical unit 102 of an electrochemical device 104, shown in Fig. 6, therefore differs from the second embodiment shown in Figs. 3 and 4 in that the sealing arrangement 100 additionally comprises a frame 162, to which the coolant channel seal 110 and both reactant channel seals 114 of each end region of the sealing arrangement 100 are connected. The frame 162 is formed from a material that has greater flexural stability than the material from which the coolant channel seal 110 and the reactant channel seals 114 are formed.

[0094] Preferably, the frame 162 is formed from a plastic material reinforced with fibers, particularly glass fibers. The frame 162 can preferably be manufactured without distortion.

[0095] The frame 162 may comprise, for example, a polyphthalamide and / or a polyphenylene sulfide.

[0096] Furthermore, the material of the frame preferably contains at least

[0097] 10% by weight of glass fibers, in particular at least 20% by weight of glass fibers, particularly preferably at least 30% by weight of glass fibers, for example at least 40% by weight of glass fibers, in a particularly preferred embodiment at least 50% by weight of glass fibers.

[0098] As can be seen from Fig. 6, the frame 162 extends at the outer edge of the sealing assembly 100 around the flow field seal 140, around the cathode gas channel seal 136, around the coolant channel seal 100 and around the anode gas channel seal 138, in each case in both end regions of the sealing assembly 100.

[0099] Therefore, during normal operation of the electrochemical device 104, the frame 162 does not come into contact with the coolant and does not come into contact with any of the reactants (anode gas or cathode gas) of the electrochemical device 104.

[0100] The frame 162 therefore does not have to meet the high resistance requirements with respect to the coolant, the anode gas and the cathode gas, which the material from which the coolant channel seal 110, the anode gas channel seal 138 and the cathode gas channel seal 136 are formed must meet.

[0101] The frame 162 is connected to the coolant channel seal 110 and the reactant channel seals 114 by a material connection, a frictional connection, and / or a form fit. In particular, it can be provided that the frame 162 is manufactured separately from the coolant channel seal 110 and the reactant channel seals 114 and is inserted into an injection mold, in which the coolant channel seal 110 and the reactant channel seals 114 are then formed from an injection-moldable material and are materially connected to the frame 162, in particular by injection molding onto the frame 162.

[0102] In order to avoid permeation of coolant molecules 130 through the frame 162 into the reactant channels 112, it is preferably provided that the solubility of the coolant in the material of the frame 162 at a temperature of 20° C is less than one mass percent, in particular less than one mass per mille.

[0103] Furthermore, it is advantageous if the diffusion coefficient of the coolant in the material of the frame 162 at a temperature of 20° C is less than 1 ■ 10' 12 m 2 / s.

[0104] As can be seen from Fig. 6, the interruption regions 134 between the coolant channel seal 110 on the one hand and the reactant channel seals 114 on the other hand extend in this embodiment through the connection region 154 of the flow field seal 140 up to the flow field seal 140, so that in this embodiment the coolant channel seal 110 and the two reactant channel seals 114 are each connected to the flow field seal 140 by separate connection regions 154a, 154b and 154c.

[0105] Otherwise, the fourth embodiment of a sealing arrangement 100 of an electrochemical unit 102 of an electrochemical device 104 shown in Fig. 6 corresponds in terms of structure, function, and method of manufacture to the second embodiment shown in Figs. 3 and 4, to the above description of which reference is made in this regard. A fifth embodiment of a sealing arrangement 100 of an electrochemical unit 102 of an electrochemical device 104 shown in detail in Fig. 7 differs from the fourth embodiment shown in Fig. 6 in that the frame 162 comprises two spacer regions 164 in each end region of the sealing arrangement 100, each of which extends into a space between the coolant channel seal 110 and an adjacent reactant channel seal 114.

[0106] Preferably, each of the spacer regions 164 extends to the flow field seal 140, which extends around a flow field 152 of the bipolar plate 118.

[0107] The spacer regions 164 further increase the mechanical stability of the sealing arrangement 100.

[0108] In addition, the risk of short circuits between the two bipolar plates 118 and 118' adjacent to the sealing arrangement 100 is reduced over the course of the operating time of the electrochemical device 104 in the area between the coolant channel seal 110 and each of the reactant channel seals 114.

[0109] In this case, the material of the frame 162 should have a very small diffusion coefficient for the coolant and a very low solubility of the coolant in the material of the frame 162 in order to prevent the coolant from permeating through the spacer regions 164 of the frame 162 from the coolant channel 108 into the reactant channels 112.

[0110] Otherwise, the fifth embodiment of a sealing arrangement 100 of an electrochemical unit 102 of an electrochemical device 104 shown in Fig. 7 corresponds in terms of structure, function and method of manufacture to the fourth embodiment shown in Fig. 6, to the above description of which reference is made in this regard. A sixth embodiment of a sealing arrangement 100 of an electrochemical unit 102 of an electrochemical device 104, shown in sections in Fig. 8, differs from the fifth embodiment shown in Fig. 7 in that the connection regions 154a, 154b and 154c, via which the coolant channel seal 110 and the reactant channel seals 114 are connected to the flow field seal 140 in the fifth embodiment shown in Fig. 7, are replaced by components of the frame 162, so that in the embodiment shown in Fig.8, the frame 162 extends completely around the coolant channel seal 110, completely around the cathode gas channel seal 136 and completely around the anode gas channel seal 138.

[0111] Since the frame 162 has only a low solubility for the coolant and a low diffusion coefficient for the coolant, this ensures that permeation from the coolant channel 108 into the flow field 152, which may in particular be an anode gas flow field or a cathode gas flow field of the bipolar plate 118, is excluded or at least reduced.

[0112] Otherwise, the sixth embodiment of a sealing arrangement 100 of an electrochemical unit 102 of an electrochemical device 104 shown in Fig. 8 corresponds in terms of structure, function and method of manufacture to the fifth embodiment shown in Fig. 7, to the above description of which reference is made in this respect.

Claims

Patent claims 1. An electrochemical device comprising a plurality of electrochemical units (102) arranged one after the other along a stacking direction (106), each comprising a sealing arrangement (100), wherein the sealing arrangement (100) comprises at least one coolant channel seal (110) surrounding a coolant channel (108) and at least one reactant channel seal (114) surrounding a reactant channel (112), wherein the coolant channel seal (110) and the reactant channel seal (114) are formed at least partially from an elastomer material, a thermoplastic material and / or a thermoset material, characterized in that the coolant channel seal (110) and the reactant channel seal (114) are separated from one another by an interruption region (134) or are formed integrally with one another via a thinning region (158),wherein a maximum extent (h) of the thinning region (158) along the stacking direction (106) of the electrochemical device (104) is less than 25% of a maximum extent (H) of the coolant channel seal (110) and / or a maximum extent (H) of the reactant channel seal (114) along the stacking direction (106) of the electrochemical device (104).

2. Electrochemical device according to claim 1, characterized in that the maximum extent (h) of the thinning region (158) along the stacking direction (106) of the electrochemical device (104) is less than 10% of the maximum extent (H) of the coolant channel seal (110) along the stacking direction (106) of the electrochemical Device (104) and / or is less than 10% of the maximum extension (H) of the reactant channel seal (114) along the stacking direction (106) of the electrochemical device (104).

3. Electrochemical device according to one of claims 1 or 2, characterized in that the at least one thinned region (158) or interrupted region (134) of the sealing arrangement (100) is arranged between a sealing lip (124, 124') of the coolant channel seal (110) and a sealing lip (126, 126') of the reactant channel seal (114).

4. Electrochemical device according to one of claims 1 to 3, characterized in that the sealing arrangement (100) comprises a frame (162) to which at least one coolant channel seal (110) and / or at least one reactant channel seal (114) of the sealing arrangement (100) is connected, wherein the frame (162) is formed from a different material than the coolant channel seal (110) and is formed from a different material than the reactant channel seal (114).

5. Electrochemical device according to claim 4, characterized in that the frame (162) comprises a polyphenylene sulfide material and / or a polyphthalamide material.

6. Electrochemical device according to one of claims 4 or 5, characterized in that the material of the frame (162) contains at least 10% by weight of glass fibers.

7. Electrochemical device according to one of claims 4 to 6, characterized in that the frame (162) is not in contact with the coolant and / or not in contact with one of the reactants of the electrochemical device (104) during normal operation of the electrochemical device (104).

8. Electrochemical device according to one of claims 4 to 7, characterized in that the frame (162) is connected to at least one coolant channel seal (110) and / or to at least one reactant channel seal (114) of the sealing arrangement (100) by material connection, by frictional connection and / or by positive connection.

9. Electrochemical device according to one of claims 4 to 8, characterized in that the solubility of the coolant in the material of the frame (162) at a temperature of 20°C is less than 1 mass percent.

10. Electrochemical device according to one of claims 4 to 9, characterized in that the diffusion coefficient of the coolant in the material of the frame (162) at a temperature of 20° C is less than 1 ■ 10' 12 m 2 / s.

11. Electrochemical device according to one of claims 4 to 10, characterized in that the frame (162) comprises at least one spacer region (164) which extends into a space between a coolant channel seal (110) and a reactant channel seal (114) of the sealing arrangement (100) or into a space between two reactant channel seals (114) of the sealing arrangement (100).

12. Electrochemical device according to claim 11, characterized in that the at least one spacer region (164) extends to a flow field seal (140) of the sealing arrangement (100), which extends around a flow field (152) of a bipolar plate (118) of the electrochemical unit (102).

13. Electrochemical device according to one of claims 4 to 12, characterized in that the frame (162) extends completely around a coolant channel seal (110) and / or around a reactant channel seal (114) and / or around at least two reactant channel seals (114) of the sealing arrangement (100).

14. Electrochemical device according to one of claims 4 to 13, characterized in that the frame (162) extends around at least one flow field seal (140) of the sealing arrangement (100).

15. Electrochemical device according to one of claims 1 to 14, characterized in that the sealing arrangement (100) comprises at least one flow field seal (140) which extends around a flow field (152) of a bipolar plate (118) of the electrochemical unit (102), wherein the coolant channel seal (110) and / or at least one reactant channel seal (114) of the sealing arrangement (100) is separated from the flow field seal (140) by an interruption region (134) and / or the coolant channel seal (110) and / or at least one reactant channel seal (114) of the sealing arrangement (100) is integrally connected to the flow field seal (140) of the sealing arrangement (100) via a thinning region (158).

16. Electrochemical device according to one of claims 1 to 15, characterized in that a flow field seal (140) which extends around a flow field (152) of a bipolar plate (118) of the electrochemical unit (112) has a connection region (154) which is formed from the same polymer material as the flow field seal (140), the coolant channel seal (110) and at least one of the at least one Reactant channel seal (114) integrally connected to the coolant channel seal (110) and the at least one of the at least one reactant channel seal (114).

17. Electrochemical device according to one of claims 1 to 16, characterized in that the thinning region (158) is formed from the same material as the coolant channel seal (110) and the reactant channel seal (114).

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