Sealing layer, separator plate and electrolyzer

Abstract

The present invention relates to a sealing layer for use in an electrolyzer, a separator plate therefor and an electrolyzer. The sealing layer has at least one sealing bead, which, when installed in the stack, in plan view of the sealing layer runs around the flow field of the separator plate in a self-contained manner and has an initial bead height H0 determined before the first compression in the stack, wherein after an initial one-time compression of the sealing layer under nominal compression in the assembled, ready-to-use state of the stack and subsequent disassembly of the stack, the self-contained sealing bead has a bead height H where H≤0.3 H0.

1 . A sealing layer for use in an electrolyzer with a stack of electrochemical cells having a separator plate with a flow field,
 wherein the sealing layer has at least one sealing bead,   which, when installed in the stack, in plan view of the sealing layer runs around the flow field of the separator plate in a self-contained manner and has an initial bead height H 0  determined before a first compression in the stack,   wherein   after an initial one-time compression of the sealing layer under nominal compression in an assembled, ready-to-use state of the stack and subsequent disassembly of the stack, the self-contained sealing bead has a bead height H where H≤0.3 H 0 .   
     
     
         2 . The sealing layer according to  claim 1 , wherein the sealing layer is the separator plate, a layer other than the separator plate, or a cell frame. 
     
     
         3 . The sealing layer according to  claim 1 , wherein after the initial one-time compression of the sealing layer and subsequent disassembly of the stack, the self-contained sealing bead has a bead height H where 2 μm≤H≤60 μm. 
     
     
         4 . The sealing layer according to  claim 1 , wherein before the first compression of the sealing layer, the self-contained sealing bead has the initial bead height H 0  where 100 μm≤H 0 ≤500 μm. 
     
     
         5 . The sealing layer according to  claim 1 , wherein the sealing layer has a thickness DL where 100 μm≤DL≤500 μm. 
     
     
         6 . The sealing layer according to  claim 1 , wherein the self-contained sealing bead is coated, at least in sections, along its longitudinal direction and/or along its transverse direction. 
     
     
         7 . The sealing layer according to  claim 1 , wherein the sealing layer, in a region enclosed by the self-contained sealing bead, has flow channels for guiding fluid reactants. 
     
     
         8 . The sealing layer according to  claim 7 , wherein the flow channels are formed as channel beads that are separated from one another by webs that extend parallel to the channel beads, or as channel beads that are separated from one another only in sections by web sections. 
     
     
         9 . The sealing layer according to  claim 8 , wherein before the first compression of the sealing layer, the flow channels in the form of channel beads have a bead height H f , where-in the self-contained sealing bead has the initial bead height H 0  where H 0 ≤0.85 H f . 
     
     
         10 . A separator plate with at least one sealing layer according to  claim 1 . 
     
     
         11 . The separator plate according to  claim 10 , comprising two metallic layers and the sealing layer. 
     
     
         12 . The separator plate according to  claim 10 , comprising two metallic layers, wherein at least one of the two metallic layers is configured as the sealing layer. 
     
     
         13 . The separator plate according to  claim 12 , wherein both of the two metallic layers are configured as the sealing layers, wherein flow channels of each of the two metallic layers run on an outer side of the separator plate. 
     
     
         14 . The separator plate according to  claim 13 , wherein before the first compression of the separator plate, the flow channels in the form of channel beads have a total bead height H f,sum  summed over the channel beads of both metallic layers, wherein the self-contained sealing beads have a summed initial bead height H 0,sum  where H 0,sum ≤0.85 H f,sum . 
     
     
         15 . An electrolyzer comprising a stack of at least two electrochemical units, wherein each of the at least two electrochemical units has at least:
 a separator plate according to  claim 10  and a flat membrane electrode assembly arranged parallel to a main plate plane of the separator plate,   wherein at least one cell frame that extends along an outer periphery of the adjacent separator plates is arranged between each two adjacent electrochemical units.   
     
     
         16 . The electrolyzer according to  claim 15 , wherein one, several or all of the electrochemical units have a further metallic layer, which is configured as a sealing layer. 
     
     
         17 . The electrolyzer according to  claim 15 , wherein each of the at least two electrochemical units has a sealing layer and at least one further metallic layer that is different from the sealing layer, and
 a further bead is arranged in the further metallic layer, parallel to the sealing bead in the sealing layer, in such a way that in a top view of the sealing layer and the further metallic layer perpendicular to a layer extension of the sealing layer, the sealing bead and the further bead run one above the other.   
     
     
         18 . The electrolyzer according to  claim 17 , wherein in a cross-section perpendicular to a plane of the sealing layer and perpendicular to a direction of extension of the sealing bead and/or the further bead, the sealing bead and the further bead have a substantially opposite course. 
     
     
         19 . The electrolyzer according to  claim 18 , wherein in the cross-section perpendicular to the plane of the sealing layer and perpendicular to the direction of extension of the sealing bead, the sealing bead and the further bead are solid beads and are configured in such a way that their bead roofs lie directly on top of one another or face away from one another.