Method for manufacturing an electrochemical cell; Electrochemical cell

Abstract

The invention relates to a method for manufacturing an electrochemical cell (1) comprising a layered structure with a first electrode (2) and a second electrode (3) separated from each other by a separator (4). According to the invention, the method comprises the following steps: a) Providing at least one electrode material (5, 6) and one separator material (11), b) Placing the at least one electrode material (5, 6) onto the separator material (11) and / or placing the separator material (11) onto the at least one electrode material (5, 6), and c) Connecting the at least one electrode material (5, 6) to the separator material (11) by sewing. Furthermore, the invention relates to an electrochemical cell (1) which is configured to carry out a process or individual steps of a process

Description

[0001] The present invention relates to a method for producing an electrochemical cell with the features of the preamble of claim 1. The electrochemical cell can, in particular, be a cell for binding gases, especially carbon dioxide (CO2). Furthermore, the invention relates to an electrochemical cell that can, in particular, be produced according to a method according to the invention.

[0002] The preferred application area of ​​the invention is electrochemical systems or plants for gas separation. State of the art

[0003] Electrochemical cells used for gas separation typically consist of at least two coated electrodes that are electrically connected. At a first electrode on the cathode side, a gas, e.g., carbon dioxide, is bound from a gas mixture through chemical processes. A second electrode on the anode side provides the electrons necessary for the separation reaction. Between the two electrodes is a separator, which is saturated with an electrolyte and permeable to ions. The separator thus ensures charge balance within the electrochemical cell. Bipolar plates are adjacent to the electrodes, separating each pair of neighboring electrochemical cells. The bipolar plates have flow channels and / or chambers that supply the gas and / or electrolyte to the surface of the cathode-side and anode-side electrodes, respectively.

[0004] To increase efficiency and the amount of bound gas, practical applications involve stacking numerous electrochemical cells and connecting them electrically to form a stack. Since a large number of electrochemical cells are required for practical applications, they should be manufactured in high volumes as cost-effectively as possible. Due to the delicate structure of individual layers, the individual electrochemical cells are susceptible to damage, yet they must still exhibit consistently high quality, as even a single defective cell can lead to a leak and / or a short circuit, thus shutting down the entire stack.The manufacturing process of electrochemical cells is particularly complex because the delicate layers and / or layers must be stacked and fixed individually and in precise positions to avoid the described risk of leakage and / or short circuits.

[0005] The present invention therefore aims to optimize the production of an electrochemical cell, in particular to simplify its manufacture. Furthermore, it seeks to increase the efficiency of the electrochemical cell.

[0006] To solve the problem, a method for manufacturing an electrochemical cell with the features of claim 1 is proposed. Furthermore, an electrochemical cell with the features of claim 7 is proposed. Advantageous embodiments of the invention are described in the respective dependent claims. Disclosure of the invention

[0007] A method for manufacturing an electrochemical cell is proposed, comprising a layered structure with a first electrode and a second electrode separated from each other by a separator. According to the invention, the method comprises the following steps: a) Providing at least one electrode material and one separator material, b) Placing the at least one electrode material onto the separator material and / or placing the separator material onto the at least one electrode material, and c) Connecting the at least one electrode material to the separator material by sewing.

[0008] Sewing the at least one electrode to the separator creates a strong bond between the sewn layers and has a fixing and stiffening effect on them. In particular, the bond between the sewn at least one electrode and the separator fixes the individual layers and / or layers to one another, thus preventing relative movement of these layers and / or layers. This reduces the risk of the at least one electrode sewn to the separator slipping during assembly or operation and coming into contact with a dead electrode, which would then lead to a short circuit and consequently a shutdown of the electrochemical cell or stack.

[0009] Furthermore, stitching at least one electrode to the separator stiffens the bonded layers, simplifying their handling. The increased stiffness of the composite makes it particularly easy to grip and position. Additionally, the number of process steps is reduced, as the bonded layers are positioned in a single step. This not only improves the handling of the layers but also simplifies the manufacturing of the electrochemical cell.

[0010] Furthermore, the efficiency of the electrochemical cell can be increased by sewing the at least one electrode to the separator. Unlike conventionally manufactured electrochemical cells, where relative movement of the electrodes and the separator is prevented by a pressing force applied by the bipolar plates, in an electrochemical cell according to the invention, the pressing force of the bipolar plates is replaced by sewing. The pressing force is therefore unnecessary. Consequently, the contact areas of the bipolar plates can be reduced and / or the distances between them increased. This, in turn, results in a larger proportion of the electrode surface adjacent to the bipolar plate being in contact with the gas or electrolyte during operation, thus increasing the efficiency of the electrochemical cell.

[0011] Preferably, in a further step, the at least one electrode material and the separator material are cut to a predetermined final dimension, wherein the further step of cutting takes place before or after step c) is performed. If cutting is done before sewing, precise cuts of the layers and / or plies to be sewn can be achieved. These then only need to be placed on top of each other and sewn together. If cutting is done after sewing, further process steps can be saved, since the electrode and separator material can be sewn in strips and subsequently cut to size to produce a large number of electrode / separator units. This reduces process time and costs in the production of the electrochemical cell.

[0012] Furthermore, preferably in step c), an electrically non-conductive yarn material is used for sewing. An electrically non-conductive yarn material is advantageous because it ensures the necessary electrical separation of the two electrodes. Otherwise, there would be a risk of a short circuit during operation of the electrochemical cell. Preferably, a yarn material from the polyamide group, for example nylon, or a yarn material made of Dyneema or aramid is used. The described yarn materials are all electrically non-conductive and generally available.

[0013] Furthermore, preferably, in step c) a thread tension of no more than 15 g is applied during joining by sewing. Sewing results in a pre-compaction of the electrode material, which reduces the surface pressure applied by the bipolar plate. However, sufficient surface pressure is necessary for contacting the electrode. If the surface pressure or contact is insufficient, the ohmic losses increase, meaning that electrical energy is lost. This can be counteracted by selecting the lowest possible thread tension.

[0014] Advantageously, in step c), a yarn material with a thread count of at least 70 m / g is used. This means that a comparatively thin yarn material is used, which nevertheless must be sufficiently tensile-strength. A thin yarn material only minimally reduces the functional surface area of ​​the at least one electrode and the separator, so this does not affect the efficiency of the electrochemical cell. Furthermore, sewing with thinner threads is technically easier, as they can penetrate the electrode and / or separator material more easily.

[0015] In a further development of the invention, at least one linear seam is formed in step c). Linear seams are particularly easy to implement technically. Preferably, several parallel and / or intersecting linear seams or seam sections are formed. The formation of several parallel and / or intersecting linear seams or seam sections allows the seams or seam sections to be distributed across the surface, so that the sewn layers and / or plies are drawn together across the surface by the yarn material. Ideally, the spacing of the seams or seam sections is regularly chosen to ensure a uniform distribution of force.

[0016] Furthermore, an electrochemical cell, in particular an electrochemical cell for binding carbon dioxide (CO2), is proposed, comprising a layered structure with a first electrode and a second electrode separated from each other by a separator. According to the invention, the first electrode and / or the second electrode is / are connected to the separator by at least one seam.

[0017] The proposed electrochemical cell can be manufactured, in particular, according to the previously described method of the invention, resulting in the same advantages for the electrochemical cell, especially the fixation of the stitched layers and / or layers to one another and thus a strong bond that is easier to handle during cell manufacturing. Furthermore, pressing the contact surfaces of the bipolar plates can be omitted, which allows the contact areas of the bipolar plates to be reduced and / or the distances between them to be increased. This increases the functional surface area of ​​the respective adjacent electrodes and thus the efficiency of the electrochemical cell.

[0018] Preferably, the at least one seam or at least one seam segment is linear and / or is located in an edge region of the at least one electrode. Linear seams are technically easy to implement. By fixing the layers and / or layers in at least one edge region, they can be positioned precisely relative to each other and held in this position. Furthermore, the seam prevents fraying in the edge region. Advantageously, therefore, the at least one seam or at least one seam segment is located in a circumferential edge region of the at least one electrode.

[0019] Preferably, several linear seams or seam sections are arranged parallel and / or intersecting each other. These multiple seams or seam sections can form a regular pattern extending over the entire surface of the assembly consisting of at least one electrode and the separator, ensuring optimal fixation between them. This regular pattern also results in a uniform distribution of the force applied by the yarn material, which pulls the stitched layers and / or plies together.

[0020] Preferably, at least one seam is made of an electrically non-conductive yarn material, preferably a yarn material from the polyamide group, for example nylon, or a yarn material made of Dyneema or aramid. An electrically non-conductive yarn material prevents short circuits and thus ensures the functionality of the electrochemical cell. The materials described are also generally available.

[0021] In a preferred embodiment of the invention, the at least one seam is produced from a yarn material with a thread thickness of at least 70 m / g. Sewing with a thin yarn material is technically easy to implement. Furthermore, thin threads result in only a slight reduction of the functional surface area of ​​the at least one electrode and the separator, so that the yarn material has no effect on the efficiency of the electrochemical cell.

[0022] Preferred embodiments of the invention are described in more detail below with reference to the figures. These show: Fig. 1 a schematic cross-section through several superimposed electrochemical cells according to a preferred embodiment of the invention and Fig. 2 a schematic cross-section through several layers and / or layers of an electrochemical cell according to the invention sewn together. Detailed description of the drawings

[0023] Fig. Figure 1 shows a schematic cross-section through several superimposed electrochemical cells 1 according to the invention for binding carbon dioxide (CO2). Each electrochemical cell 1 has several layers and / or layers which are arranged in a stacked configuration. These include, in particular, a first electrode 2 on the cathode side made of an electrode material 5, a second electrode 3 on the anode side made of an electrode material 6, and a separator 4 made of a separator material 11 arranged between the electrodes 2 and 3. A bipolar plate 9, which is electrically conductive and in contact with the electrodes 2 and 3, is also arranged between two electrochemical cells 1. The bipolar plate 9 has a region projecting laterally beyond the electrodes 2 and 3. A sealing element 10 is arranged in this region to electrically insulate two superimposed bipolar plates 9 from each other.The first cathode-side electrode 2 is in contact with a gas via a surface 12 during operation. It is capable of binding the gas through an electrochemical reaction. The second anode-side electrode 3 is capable of providing electrons for gas deposition. The separator 4, arranged between electrodes 2 and 3, is permeable to ions and ensures charge balance in the electrochemical cell 1.

[0024] The various layers and / or layers of an electrochemical cell must be precisely positioned and secured against slippage during stacking. Conventionally, this securing is achieved by pressing the layers and / or layers together. The pressing force is applied via the intervening bipolar plates 9. Before and during pressing, an undesired displacement of a layer and / or layer can occur. To prevent this, in an electrochemical cell 1 according to the invention, at least one electrode 2, 3 and the separator 4 are connected to each other by at least one seam 8.

[0025] Fig. Figure 2 shows an enlarged cross-section through two electrodes 2, 3 and a separator 4 arranged between them of an electrochemical cell 1 according to the invention, which are sewn together. The at least one seam 8 is made of a thin, electrically non-conductive yarn material 7, for example Dyneema, aramid, nylon or a yarn material 7 from the polyamide group. The at least one seam 8 or at least a seam segment of the seam runs linearly.

[0026] The production of the in the Fig.The arrangement shown in Figure 2 comprises the provision of electrode material 5, 6 and a separator material 11. The separator material 11 is placed on top of a first electrode material 6. Subsequently, a second electrode material 5 is placed on top of the separator material 11. The stack is then sewn together using a thread material 7, forming a seam 8 connecting the electrodes 2, 3 and the separator 4. The electrode material 5, 6 and the separator material 11 can be cut to size either before stacking the materials 5, 6, 11 or after sewing them together.

[0027] Sewing the at least one electrode 2, 3 to the separator 4 creates a bond that facilitates the handling of these layers and / or layers during the manufacturing process. This simplifies the manufacturing process of the electrochemical cell 1. In particular, sewing the at least one electrode 2, 3 to the separator 4 reduces the number of process steps in the production of the electrochemical cell 1. If both electrodes 2, 3 are sewn together, the number of process steps is even halved. Furthermore, sewing the at least one electrode 2, 3 to the separator 4 prevents relative movement between them, thus minimizing the risk of short circuits during operation.

Claims

[1] Method for producing an electrochemical cell (1) comprising a layered and / or layered structure with a first electrode (2) and a second electrode (3) separated from each other by a separator (4), characterized by the following steps: a) Providing at least one electrode material (5, 6) and one separator material (11), b) Placing the at least one electrode material (5, 6) onto the separator material (11) and / or placing the separator material (11) onto the at least one electrode material (5, 6), and c) Connecting the at least one electrode material (5, 6) to the separator material (11) by sewing. [2] Method according to claim 1, characterized by , that in a further step the at least one electrode material (5, 6) and the separator material (11) are cut to a predetermined final dimension, wherein the further step of cutting takes place before or after step c). [3] Method according to claim 1 or 2, characterized by , that in step c) an electrically non-conductive yarn material (7) is used for sewing, preferably a yarn material (7) from the group of polyamides, for example nylon, or a yarn material (7) made of Dyneema or aramid. [4] Method according to any one of the preceding claims, characterized by , that in step c) a yarn material (7) with a thread thickness of at least 70 m / g is used. [5] Method according to any one of the preceding claims, characterized by , that in step c) at least one linearly extending seam (8), preferably several parallel and / or intersecting, linearly extending seams (8) or seam sections, is or are formed. [6] Method according to any one of the preceding claims, characterized by , that in step c) when joining by sewing a thread tension of a maximum of 15 g is applied. [7] Electrochemical cell (1), in particular electrochemical cell (1) for binding carbon dioxide (CO2), comprising a layered and / or layered structure with a first electrode (2) and a second electrode (3) which are separated from each other by a separator (4), characterized by that the first electrode (2) and / or the second electrode (3) is / are connected to the separator (4) by at least one seam (8). [8] Electrochemical cell (1) according to claim 7, characterized by , that the at least one seam (8) or at least one seam section is linear and / or is located in an edge region of the at least one electrode (2, 3). [9] Electrochemical cell (1) according to claim 7 or 8, characterized by , that several linear seams (8) or seam sections are arranged parallel and / or intersecting each other. [10] Electrochemical cell (1) according to any one of claims 7 to 9, characterized by, that the at least one seam (8) is made of an electrically non-conductive yarn material (7), preferably a yarn material (7) from the group of polyamides, for example nylon, or a yarn material (7) made of Dyneema or aramid. [11] Electrochemical cell (1) according to any one of claims 7 to 10, characterized by , that at least one seam (8) is made from a yarn material (7) with a thread thickness of at least 70 m / g.

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