Electrochemical cell with thermosetting monomer layer
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- ROBERT BOSCH GMBH
- Filing Date
- 2026-01-09
- Publication Date
- 2026-07-30
Smart Images
Figure EP2026050396_30072026_PF_FP_ABST
Abstract
Description
[0001] R.416621
[0002] - 1 -
[0003] Description
[0004] Methods for manufacturing an electrochemical cell and electrochemical cell
[0005] The invention relates to a method for manufacturing an electrochemical cell and to an electrochemical cell that can be manufactured, in particular, according to the proposed method. The electrochemical cell can, in particular, be an electrolysis cell or a fuel cell, preferably a PEM-based fuel cell.
[0006] A preferred application of the invention is electrolysis or fuel cell systems comprising at least one cell stack composed of a plurality of electrochemical cells. The stack may, for example, be a PEM or AEM electrolysis stack for hydrogen production or a PEM-based fuel cell stack.
[0007] State of the art
[0008] Electrochemical cells have a multilayered structure. The central layer is a membrane, followed by catalyst layers on both sides of the membrane to form an anode and a cathode. For this purpose, the membrane is typically coated on both sides with a catalyst material. In the case of an electrolysis cell, porous transport layers (PTLs) are arranged on both sides of the catalyst layers for the supply and removal of an electrolyte and the removal of the respective product gases. In the case of a fuel cell, gas diffusion layers (GDLs) are arranged on both sides of the catalyst layers, through which the respective reaction gases are supplied to the membrane. Monopolar or bipolar plates form the end caps of both electrolysis and fuel cells, serving to separate two stacked cells. R.416621
[0009] - 2 -
[0010] During operation of an electrochemical cell, the membrane can become damaged, for example in the form of a tear or a hole, the so-called "pin hole". In this case, there is no longer effective separation of the anode side from the cathode side, so that the gases present there, usually hydrogen and oxygen, can mix and form an explosive gas mixture. This has significant implications for the operational safety of the electrolysis or fuel cell system.
[0011] The present invention therefore aims to reduce the sensitivity of an electrochemical cell membrane to prevent damage in the form of a membrane tear or pinhole. The result is to increase the operational reliability of an electrolysis or fuel cell system.
[0012] To solve the problem, the method with the features of claim 1 and the electrochemical cell with the features of claim 7 are proposed. Advantageous embodiments of the invention can be found in the respective dependent claims.
[0013] Disclosure of the invention
[0014] A method for manufacturing an electrochemical cell, in particular an electrolysis or fuel cell, is proposed, comprising a membrane, catalyst layers arranged on both sides of the membrane to form an anode and a cathode, and porous transport or gas diffusion layers adhering to the catalyst layers. According to the invention, at least one thermosetting monomer layer is
[0015] a) into the membrane or
[0016] b) between the catalyst layers and the respective adjacent porous transport or gas diffusion layer
[0017] introduced, whereby the monomer layer is continuous or interrupted multiple times. R.416621
[0018] - 3 -
[0019] When membrane defects occur, such as a membrane tear or a pinhole, this is accompanied by a temperature increase at the affected area. This is due to the relatively high current densities generated across the membrane surface, which induce so-called hot spots. The temperature increase, in turn, leads to the hardening of the monomer layer, thus closing the tear or hole in the membrane.
[0020] The curing time for temperature-induced curing depends on the specific temperature. Generally, the curing time decreases with increasing temperature. Therefore, there is a positive correlation between crack or hole size and temperature increase, which in turn reduces the curing time.
[0021] Preferably, a monomer is chosen that remains liquid or at least viscous under normal operating conditions or temperatures and only hardens under elevated operating temperatures, such as those generated by a membrane rupture or a pin hole.
[0022] Furthermore, it is preferably preferred that an electrically non-conductive and ion- and water-permeable monomer is used to form the at least one monomer layer. This ensures that the function of the membrane is not impaired by the monomer layer. The membrane's function includes separating the anode from the cathode and transporting water and / or protons across the membrane. For example, a thermosetting epoxy or methacrylate can be used to form the at least one monomer layer.
[0023] According to a first preferred embodiment, when performing step a), the at least one monomer layer is introduced centrally into the membrane. The central arrangement requires only one monomer layer and is therefore simpler to manufacture. Furthermore, monomer can be saved.
[0024] According to a second preferred embodiment, when performing step a), the at least one monomer layer is introduced into an edge region of the membrane. The edge region of the membrane is more easily accessible, thus facilitating the introduction of the monomer layer. To the membrane R.416621
[0025] - 4 -
[0026] To provide optimal protection, a monomer layer is preferably introduced into both edge regions of the membrane in this case. As a further development measure, it is therefore proposed that a first monomer layer be introduced into an anode-side edge region and a second monomer layer into a cathode-side edge region of the membrane.
[0027] According to a third preferred embodiment, when performing step b), the porous transport or gas diffusion layers are each coated with a thermosetting monomer. This embodiment is particularly easy to implement, thus reducing manufacturing effort and costs.
[0028] Ideally, the monomer layer is made as thin as possible to avoid excessively increasing the membrane thickness, as this would have disadvantages such as increased resistance. Therefore, it is preferred that the at least one monomer layer has a thickness of less than 50%, preferably less than 25%, of the membrane thickness, and furthermore preferably in the range of 1 to 20 pm.
[0029] Furthermore, an electrochemical cell, in particular an electrolysis or fuel cell, is proposed. The electrochemical cell comprises a membrane, catalyst layers arranged on both sides of the membrane to form an anode and a cathode, and porous transport or gas diffusion layers adhering to the catalyst layers. According to the invention, at least one thermosetting monomer layer is included.
[0030] a) into the membrane or
[0031] b) between the catalyst layers and the respective adjacent porous transport or gas diffusion layer
[0032] introduced, whereby the monomer layer is continuous or interrupted multiple times.
[0033] The proposed electrochemical cell is less susceptible to membrane defects such as cracks or holes, thus ensuring safe media separation within the cell. In particular, the reaction or product gases, hydrogen and oxygen, remain separate, preventing the formation of an explosive gas mixture. R.416621
[0034] - 5 -
[0035] This increases the operational reliability of the cell or of a stack containing the cell in an electrolysis or fuel cell system.
[0036] The proposed electrochemical cell can in particular be manufactured according to the previously described inventive method, so that the associated advantages can be achieved.
[0037] The at least one monomer layer is preferably formed from an electrically non-conductive and ion- and water-permeable monomer. This ensures that the at least one monomer layer does not impair the function of the membrane. The at least one monomer layer can, for example, be formed from a thermosetting epoxy or methacrylate.
[0038] Preferably, in case a), the at least one monomer layer is placed centrally in the membrane. With a central arrangement, the number of monomer layers can be reduced to one. This saves material. Furthermore, the thickness of the membrane changes only slightly.
[0039] Alternatively, it is proposed that in case a), the at least one monomer layer is introduced into an edge region of the membrane. The edge region facilitates insertion, as it is easily accessible. Preferably, in this case, a first monomer layer is introduced into an anode-side edge region and a second monomer layer into a cathode-side edge region of the membrane. The membrane is thus optimally protected.
[0040] Furthermore, it is proposed that in case b), the porous transport or gas diffusion layers are each coated with a thermosetting monomer. This further simplifies the production of the at least one monomer layer.
[0041] The at least one monomer layer preferably has a thickness that is less than 50%, preferably less than 25%, of the membrane thickness, and furthermore preferably in the range of 1 to 20 pm. When the at least one monomer layer is introduced into the membrane, this prevents excessive R.416621.
[0042] - 6 -
[0043] Increasing the membrane thickness can be avoided. Furthermore, material can be saved regardless of the application method.
[0044] Preferred embodiments of the invention and their advantages are explained in more detail below with reference to the accompanying drawings. These show:
[0045] Fig. 1 shows a schematic cross-section through a first electrochemical cell according to the invention,
[0046] Fig. 2 shows a schematic cross-section through a second electrochemical cell according to the invention,
[0047] Fig. 3 shows a schematic cross-section through a third electrochemical cell according to the invention and
[0048] Fig. 4 shows a schematic cross-section through a fourth electrochemical cell according to the invention.
[0049] Detailed description of the drawings
[0050] Figure 1 shows an electrochemical cell 1, for example, an electrolysis or fuel cell. The cell 1 has a membrane 2 and catalyst layers 3 arranged on both sides of the membrane 2 to form an anode and a cathode. Figure 1 does not differentiate further between the anode and the cathode. The catalyst layers 3 and the porous transport or gas diffusion layers 4 adjacent to the catalyst layers 3 are each enclosed on both sides of the membrane 2 by a frame 6.
[0051] Figure 1 shows a monomer layer 5 inserted centrally into the membrane 2, which in this case is continuous. The monomer layer 5 is formed from a thermosetting monomer that remains liquid at normal operating temperatures and only hardens upon an increase in temperature, such as occurs in the case of a crack or hole in the membrane 2. The crack or hole is then closed by the hardening monomer.
[0052] As an alternative to the embodiment of Figure 1, the monomer layer 5 can also be placed in at least one edge region of the R.416621, as shown by way of example in Figure 2.
[0053] - 7 -
[0054] Membrane 2 is inserted. In this case, a monomer layer 5 made of a thermosetting monomer is inserted into each of the two edge regions of membrane 2. The double layer increases the protection of membrane 2. The edge-side arrangement of the monomer layers 5 facilitates their production.
[0055] The at least one monomer layer 5 need not necessarily be continuous, but can also be interrupted multiple times. This embodiment is illustrated by way of example in Figures 3 and 4, where Figure 3 shows a central arrangement of the monomer layer 5 and Figure 4 shows an edge arrangement of two monomer layers 5.
[0056] Not shown is the variant in which at least one monomer layer 5 is introduced between the catalyst layers 3 and the respective adjacent porous transport or gas diffusion layer 4. In this case, the introduction of the monomer layer 5 can be achieved by coating the porous transport or gas diffusion layer 4 with a thermosetting monomer.
Claims
R.416621 - 8 - Claims 1. Method for producing an electrochemical cell (1), in particular an electrolysis or fuel cell, comprising a membrane (2), catalyst layers (3) arranged on both sides of the membrane (2) to form an anode and a cathode, and porous transport or gas diffusion layers (4) adjoining the catalyst layers (3), characterized in that at least one heat-curing monomer layer (5) c) into the membrane (2) or d) between the catalyst layers (3) and the respective adjacent porous transport or gas diffusion layer (4) is introduced, whereby the monomer layer (5) is made continuous or interrupted multiple times.
2. Method according to claim 1 , characterized in that an electrically non-conductive and ion- and water-permeable monomer, for example a thermosetting epoxy or methacrylate, is used to form the at least one monomer layer (5).
3. Method according to claim 1 or 2, characterized in that, when step a) is carried out, the at least one monomer layer (5) is inserted centrally into the membrane (2).
4. Method according to claim 1 or 2, characterized in that, in the execution of step a), the at least one monomer layer (5) is introduced into an edge region of the membrane (2), wherein preferably a first monomer layer (5) is introduced into an anode-side edge region and a second monomer layer (5) is introduced into a cathode-side edge region of the membrane (2). R.416621 - 9 - 5. Method according to claim 1 or 2, characterized in that, when carrying out step b), the porous transport or gas diffusion layers (4) are each coated with a thermosetting monomer.
6. Method according to any one of the preceding claims, characterized in that the at least one monomer layer (5) is made in a thickness (d) that is less than 50%, preferably less than 25%, of the membrane thickness, and further preferably in the range of 1 to 20 pm.
7. Electrochemical cell (1), in particular electrolysis or fuel cell, comprising a membrane (2), catalyst layers (3) arranged on both sides of the membrane (2) to form an anode and a cathode, and porous transport or gas diffusion layers (4) adjoining the catalyst layers (3), characterized in that at least one heat-curing monomer layer (5) a) into the membrane (2) or b) between the catalyst layers (3) and the respective adjacent porous transport or gas diffusion layer (4) is introduced, wherein the monomer layer (5) is continuous or interrupted multiple times.
8. Electrochemical cell (1) according to claim 7, characterized in that the at least one monomer layer (5) is formed from an electrically non-conductive and ion- and water-permeable monomer, for example from a thermosetting epoxy or methacrylate.
9. Electrochemical cell (1) according to claim 7 or 8, characterized in that, in case a), the at least one monomer layer (5) is inserted centrally into the membrane (2). R.416621 - 10 - 10. Electrochemical cell (1) according to claim 7 or 8, characterized in that in case a) the at least one monomer layer (5) is introduced into an edge region of the membrane (2), wherein preferably a first monomer layer (5) is introduced into an anode-side edge region and a second monomer layer (5) is introduced into a cathode-side edge region of the membrane (2).
11. Electrochemical cell (1) according to claim 7 or 8, characterized in that in case b) the porous transport or gas diffusion layers (4) are each coated with a thermosetting monomer.
12. Electrochemical cell (1 ) according to one of claims 7 to 11 , characterized in that the at least one monomer layer (5) has a thickness (d) which is less than 50%, preferably less than 25%, of the membrane thickness, further preferably in the range of 1 to 20 pm.