Bipolar plate for an electrochemical system and corresponding electrochemical system comprising such a bipolar plate

Patent metadata

Field	Value
Publication number	US-2025038222-A1
Application number	US-202418785881-A
Country	US
Kind code	A1
Filing date	Jul 26, 2024
Priority date	Jul 28, 2023
Publication date	Jan 30, 2025
Grant date	—

Abstract

The present disclosure relates to a bipolar plate for an electrochemical system, having a first separator plate and a second separator plate that are arranged one on top of the other, wherein the first separator plate has, on a side facing away from the second separator plate, a first electrochemically active surface for conducting a first fluid; the second separator plate has, on a side facing away from the first separator plate, a second electrochemically active surface for conducting a second fluid; wherein the first electrochemically active surface and the second electrochemically active surface overlap each other and form an active region of the bipolar plate in an overlapping region, wherein the separator plates are joined together in the active region by a weld pattern with inhomogeneously distributed welds.

First claim

1 . A bipolar plate for an electrochemical system, having a first separator plate and a second separator plate that are arranged one on top of the other, wherein
the first separator plate has, on a side facing away from the second separator plate, a first electrochemically active surface for conducting a first fluid; the second separator plate has, on a side facing away from the first separator plate, a second electrochemically active surface for conducting a second fluid;
wherein the first electrochemically active surface and the second electrochemically active surface overlap each other and form an active region of the bipolar plate in an overlapping region,
wherein the first separator plate and the second separator plate are joined together in the active region by a weld pattern with inhomogeneously distributed welds.

2 . The bipolar plate according to claim 1 , wherein a distance between adjacent welds in a first region of the weld pattern is greater than in a second region of the weld pattern.

3 . The bipolar plate according to claim 1 , wherein the first electrochemically active surface comprises a first region and a second region,
wherein the welds are distributed such that an areal density of the welds in the first region, F1, is smaller than an areal density of the welds in the second region, F2.

4 . The bipolar plate according to claim 3 , wherein a ratio, F1/F2, between the areal density of the welds in the first region, F1, and the areal density of the welds in the second region, F2, is less than 0.9.

5 . The bipolar plate according to claim 3 , wherein a surface proportion of the first region and/or the second region in each case amounts to at least 5% of a total area of the active region and/or wherein the first region and the second region have the same area.

6 . The bipolar plate according to claim 1 , wherein the first electrochemically active surface comprises a first region, a second region and a third region, wherein the second region is arranged between the first region and the third region with respect to a flow direction of a fluid,
wherein the weld pattern is configured such that areal densities of the welds in the said regions of the first electrochemically active surface deviate from one another by more than 5%.

7 . The bipolar plate according to claim 6 , wherein only the second region, or the second region and the first region, or the second region and the third region have welds.

8 . The bipolar plate according to claim 1 , wherein the welds are arranged in an area of channels for conducting the first fluid and/or in an area of channels for conducting the second fluid.

9 . The bipolar plate according to claim 1 , wherein the welds of the weld pattern are spaced from an outer edge of the active region, wherein a distance between each weld and the outer edge is greater than 2 mm.

10 . The bipolar plate according to claim 1 , wherein the welds of the weld pattern are spaced apart from an outer edge of the active region, wherein at least 1 channel is arranged between each weld and the outer edge.

11 . The bipolar plate according to claim 1 , wherein the first electrochemically active surface is at least partly surrounded by a first sealing element of the first separator plate and the welds are spaced apart from the first sealing element, wherein a minimum distance between each weld and the first sealing element is greater than 5 mm.

12 . The bipolar plate according to claim 1 , wherein the bipolar plate is adapted to be operated at a particular operating point of a fuel cell, wherein the particular operating point comprises a particular concentration gradient of the first fluid along the first electrochemically active surface,
wherein the weld pattern is adapted to the concentration gradient of the first fluid, so that a first areal density of the welds in regions of the active region of comparatively low concentration of the first fluid is comparatively large and a second areal density of the welds in regions of the active region of comparatively high concentration of the first fluid is comparatively small.

13 . The bipolar plate according to claim 1 , wherein the first separator plate comprises a first inlet port for letting in the first fluid and a first outlet port for discharging the first fluid,
wherein the first inlet port is fluidically connected to the first electrochemically active surface via a first inlet region and the first outlet port is fluidically connected to the first electrochemically active surface via a first outlet region such that the first fluid can be passed successively through the first inlet region, the first electrochemically active surface and the first outlet region, wherein the first separator plate and the second separator plate are connected to one another by further welds, which are arranged in the first inlet region and/or in the first outlet region.

14 . The bipolar plate according to claim 1 , designed such that a flow direction of the first fluid is opposite to a flow direction of the second fluid, wherein an areal density of the welds in the second electrochemically active surface decreases with the flow direction of the second fluid and the areal density of the welds in the second electrochemically active surface increases with the flow direction of the first fluid.

15 . The bipolar plate according to claim 1 , configured such that a flow direction of the first fluid is parallel to a flow direction of the second fluid, wherein an areal density of the welds in the second electrochemically active surface increases with the flow direction of the first fluid and the flow direction of the second fluid.

16 . The bipolar plate according to claim 1 , wherein the first separator plate is a cathode plate and the second separator plate is an anode plate, wherein the first fluid is oxygen or air and/or the second fluid is hydrogen, methanol or another proton donor.

17 . The bipolar plate according to claim 1 , wherein within a channel, at least in sections, a length of the welds and/or a distance between welds being closest to one another is between 0.05 mm and 3 mm.

18 . The bipolar plate according to claim 1 , wherein in sections, at the most four channels are situated between two welds being closest to one another on a line extending orthogonal or traverse to a main extension direction of a channel.

19 . An arrangement for the electrochemical system having the bipolar plate according to claim 1 and at least one membrane electrode assembly (MEA) with a frame-shaped reinforcing edge, the MEA and the bipolar plate being arranged one on top of the other in a stacking direction and the active region of the bipolar plate being enclosed in orthogonal projection in a common plane by the frame-shaped reinforcing edge of the MEA.

20 . The arrangement according to claim 19 , wherein the weld pattern of the bipolar plate is spaced from the frame-shaped reinforcing edge in a direction perpendicular to the stacking direction by at least 2 mm.

Assignees

• Reinz Dichtungs Gmbh

Inventors

• Gaugler Bernd
• Luksch Christian
• Oruc Ahmet
• Speidel André
• Wenzel Stephan

Classifications

• H01M8/0202

  Collectors; Separators, e.g. bipolar separators; Interconnectors · CPC title

• H01M8/0297

  Arrangements for joining electrodes, reservoir layers, heat exchange units or bipolar separators to each other (H01M8/0271 takes precedence) · CPC title

• H01M8/0258 Primary

  characterised by the configuration of channels, e.g. by the flow field of the reactant or coolant · CPC title

• H01M8/0204

  Non-porous and characterised by the material · CPC title

• H01M8/1004 Primary

  characterised by membrane-electrode assemblies [MEA] (H01M8/12 takes precedence) · CPC title