Electrochemical cell

Abstract

The utility model relates to an electrochemical cell (1), especially an electrolytic cell. The electrochemical cell (1) comprises a catalyst-coated membrane (100), diffusion layers (5, 6) arranged on both sides of the catalyst-coated membrane and a sealing frame (40). The sealing frame (40) is arranged around the catalyst-coated membrane (100) and the diffusion layers (5, 6). The sealing frame (40) has a step (45), wherein the catalyst-coated membrane (100) is placed on the step (45). The catalyst-coated membrane (100) is positioned within the sealing frame (40) by means of at least one positioning pin (50) arranged at the step (45).

Description

Technical Field

[0001] This utility model relates to an electrochemical battery. Background Technology

[0002] Electrochemical cells (e.g., fuel cells or electrolyzers) having membrane electrode assemblies and bipolar plates arranged on both sides are known in the prior art, for example from EP3969640B1. This electrochemical cell includes a catalyst-coated membrane, diffusion layers arranged on both sides of the catalyst-coated membrane, and a sealing frame. The sealing frame is arranged around the catalyst-coated membrane and diffusion layers. The sealing frame has steps on which the catalyst-coated membrane is placed.

[0003] The sealing scheme for this type of electrochemical battery (especially in terms of sealing function, positioning accuracy and operability) is a subject of continuous improvement. Utility Model Content

[0004] This utility model relates to an electrochemical cell, and more particularly to an electrolytic cell. The electrochemical cell includes a catalyst-coated film, diffusion layers arranged on both sides of the catalyst-coated film, and a sealing frame. The sealing frame is arranged around the catalyst-coated film and the diffusion layers. The sealing frame has steps, on which the catalyst-coated film is placed. The catalyst-coated film is positioned within the sealing frame by means of at least one locating pin arranged at the step.

[0005] This improves the positioning accuracy of the catalyst coating relative to the sealing frame, and consequently relative to the rest of the electrochemical cell. Furthermore, the operability of the catalyst coating during assembly is also improved when it is fixed within the sealing frame.

[0006] Advantageously, the locating pin works in conjunction with a recess constructed in the catalyst coating film. For this purpose, the locating pin can be implemented as a column, and the recess as a hole. If the locating pin extends through the recess, it engages with the catalyst coating film in the xy plane, thereby locking the catalyst coating film in a shape-locking manner within the xy plane.

[0007] In a preferred extended embodiment, the catalyst-coated membrane includes a membrane and electrode layers arranged on both sides of the membrane. The electrode layers are arranged on the membrane only by means of an active surface, which is defined by the inner periphery of a sealing frame. Therefore, the electrode layers can be positioned with extremely high precision relative to the sealing frame, and thus relative to the active surface, by means of locating pins. Therefore, this invention is particularly suitable for non-fully coated membranes, i.e., for cases where the area of ​​the electrode layer is smaller than the area of ​​the membrane.

[0008] In a favorable extension, at least two locating pins each interact with a recess. These two locating pins are essentially cylindrical. These two recesses are essentially elliptical in shape. The elliptical direction of the first recess... It is implemented orthogonally to the elliptical direction of the second concave cavity. Therefore, the positioning of the catalyst coating film in the xy plane can achieve extremely narrow tolerances.

[0009] For example, the elliptical direction of the first recess extends along the x-direction, while the elliptical direction of the second recess extends along the y-direction. Here, the locating pin in the first recess is used to fix the catalyst coating film in the y-direction; while the locating pin in the second recess is used to fix the catalyst coating film in the x-direction. The elliptical directions compensate for tolerances in directions where positioning is not required.

[0010] In an advantageous embodiment, the locating pin is locked to the sealing frame material, for example by adhesive or welding.

[0011] In a preferred extension, one of the diffusion layers is also positioned within the sealing frame by means of a locating pin. This diffusion layer is the larger of the two diffusion layers and is also indirectly placed on the steps of the sealing frame. In the case of an electrolytic cell, this diffusion layer is preferably an anode-side diffusion layer. Therefore, the locating pin is used for positioning both the catalyst coating film and the diffusion layer. It is particularly advantageous here that the diffusion layer has a flow structure toward the catalyst coating film. Thus, the flow structure can achieve extremely high-precision alignment with respect to the catalyst coating film (especially its corresponding electrode layer).

[0012] In an advantageous embodiment, the electrochemical cell is an electrolytic cell, particularly preferably a PEM electrolytic cell. PEM membranes (Proton Exchange Membranes) are relatively thin and difficult to handle. However, their operability is improved when they are securely arranged in a sealed frame, especially when subsequent assembly is further stabilized by a diffusion layer. Attached Figure Description

[0013] Embodiments of this utility model are shown in the accompanying drawings and described in detail below. They show:

[0014] Figure 1 A schematic cross-section of an electrochemical cell in the prior art, showing only the key areas.

[0015] Figure 2 A schematic cross-section of another electrochemical cell with a sealed frame in the prior art, showing only the key areas.

[0016] Figure 3 A schematic cross-section of the electrochemical cell according to the present invention is shown, wherein only key areas are shown.

[0017] Figure 4 A schematic top view of the electrochemical cell according to the present invention, wherein only key areas are shown. Detailed Implementation

[0018] Figure 1 A schematic cross-section of an electrochemical cell 1 (in the form of an electrolytic cell) known in the prior art is shown, wherein only key areas are shown. The electrolytic cell 1 has an electrolyte 2 (e.g., a membrane, especially a polymer electrolyte membrane), and therefore the electrolytic cell 1 is preferably implemented as a PEM electrolytic cell. Viewed along the stacking direction z, a cathode chamber 1a is constructed on one side of the membrane 2, and an anode chamber 1b is constructed on the other side.

[0019] In cathode chamber 1a, an electrode layer 3, a diffusion layer 5, and a distribution plate 7 are arranged outward from membrane 2 (i.e., along the normal z direction). Correspondingly, in anode chamber 1b, an electrode layer 4, a diffusion layer 6, and a distribution plate 8 are arranged outward from membrane 2.

[0020] The combination of membrane 2 and the two electrode layers 3 and 4 constitutes the catalyst-coated membrane 100. Alternatively, membrane 2 may be coated with only one of the two electrode layers 3 and 4; in this case, the other electrode layer 3 and 4 is arranged on the membrane-side surface of the associated diffusion layers 5 and 6.

[0021] The catalyst-coated membrane 100 and the two diffusion layers 5 and 6 constitute the membrane electrode unit 10. The diffusion layers 5 and 6 may also have a multilayer structure.

[0022] The distribution plates 7 and 8 have channels 11 for conveying and discharging media (e.g., hydrogen in cathode chamber 1a and water in anode chamber 1b) to and from the diffusion layers 5 and 6. The diffusion layers 5 and 6 may be composed, for example, of fiber felt and / or porous metal layers.

[0023] The distribution plates 7 and 8 have channels 11, and therefore correspondingly have tabs 12 for the boundary channels 11. The lower sides of these tabs 12 form contact surfaces 7a and 8a of the respective distribution plates 7 and 8, which are opposite to the corresponding contact surfaces 5a and 6a of the diffusion layers 5 and 6 below.

[0024] The cathode-side distribution plate 7 of the electrochemical cell 1 and the anode-side distribution plate 8 of the adjacent electrochemical cell can be fixedly connected (e.g., by welding) at their connection surface 20b to form a bipolar plate 20. The distribution plates 7 and 8 can also be implemented integrally, thus eliminating the need for a second distribution plate 8. In this case, the distribution plate 7 can also be implemented without the channel 11; in this case, the bipolar plate 20 is a flat distribution plate 7, and the actual dielectric distribution takes place entirely within the diffusion layers 5 and 6.

[0025] Figure 2A cross-section of an electrochemical cell 1 (in the form of an electrolytic cell) known from EP3969640B1 is shown, with only key areas shown. The electrolytic cell 1 is surrounded at its periphery by a sealing frame 40. A seal 41 is arranged within a recess 42 constructed in the sealing frame 40 and works in conjunction with a catalyst-coated film 100 to functionally seal the cathode chamber 1a relative to the anode chamber 1b.

[0026] The sealing frame 40 has a step 45 with a support surface for placing the catalyst-coated film 100. A recess 42 is arranged in this support surface. The step 45 results in the sealing frame 40 having windows of different sizes for the cathode-side diffusion layer 5 and the anode-side diffusion layer 6; preferably, the window for the anode-side diffusion layer 6 is configured to be larger. The sealing frame 40 defines the active surface 120 of the electrochemical cell 1 through its smaller window, i.e., the surface where the two electrode layers 3, 4 are almost freely contactable with ions or reaction fluids; in other words, within tolerance, the active surface 120 corresponds to the area of ​​the smaller diffusion layer 5, or also to the minimum inner periphery 49 of the sealing frame 40.

[0027] Reasonably, the dimensions of the catalyst coating 100 should be selected such that it reliably extends beyond the seal 41 under all tolerance conditions, as... Figure 2 As shown. Next, the first gas diffusion layer 6 is placed on the catalyst coating film 100 from above. The dimensions of the anode-side diffusion layer 6 should be selected such that it can extend beyond the surface surrounded by the seal 41, so that it can transmit the sealing force to the seal 41 as a contact pair with respect to the catalyst coating film 100. In other words, the anode-side diffusion layer 6 is indirectly placed on the step 45 of the sealing frame 40.

[0028] To better position the catalyst coating film 100 within the sealing frame 40, according to this invention, at least one positioning pin is arranged on the sealing frame 40. Figure 3 A cross-section of the electrochemical cell 1 (in the form of an electrolytic cell) according to the present invention is shown, wherein only the key areas are shown.

[0029] The catalyst-coated film 100 is placed on the step 45 of the sealing frame 40 and clamped between the anode-side diffusion layer 6 and the step 45. A locating pin 50 is arranged at the step 45 and penetrates the catalyst-coated film 100 through a recess 110 constructed within it. Therefore, the locating pin 50 and the catalyst-coated film 100 form an engagement (i.e., a form-locking connection) in the recess 110 within the xy-plane, thereby positioning the catalyst-coated film 100 within tolerances in the xy-plane. The locating pin 50 can be fixedly connected to the sealing frame 40 (e.g., by adhesive or welding) or assembled with the sealing frame.

[0030] Figure 4 A top view of the electrochemical cell 1 according to the present invention is shown, wherein only key areas are shown. Figure 4 In the illustrated embodiment, the catalyst-coated film 100 is positioned relative to the sealing frame 40 by means of five positioning pins 50 arranged on the sealing frame 40. These positioning pins 50 are configured at the steps 45 of the sealing frame 40. Thus, the active surface 120 of the catalyst-coated film 100 can also be oriented relative to the sealing frame 40. Particularly advantageously, the electrode layers 3 and 4 do not cover the entire surface of the film 2, but only the active surface 120. Therefore, the electrode layers 3 and 4 are preferably configured to extend only to the inner periphery 49 of the sealing frame 40, which surrounds the smaller of the two diffusion layers 5. Similarly, the electrode layers 3 and 4 can also be applied to the diffusion layers 5 and 6, but only within the area of ​​the smaller of the two diffusion layers 5 and 6.

[0031] By providing positioning pins 50 at the step 45 of the sealing frame 40, the catalyst coating film 100 can be oriented relative to the sealing frame 40, and further relative to the active surface 120 of the electrochemical cell 1, by means of the recesses 110 corresponding to the positioning pins 50. The positioning pins 50 can be arranged in any number at any position on the step 45. The positioning pins 50 can be, for example, cylindrical or conical. The positioning pins 50 are fixedly connected to the sealing frame 40.

[0032] The positioning pins 50 can also be used to position other components of the electrochemical cell 1, such as the corresponding diffusion layer 6 or any stabilizing film used for the stabilizing film 2.

Claims

1. An electrochemical cell (1) having a catalyst-coated membrane (100), diffusion layers (5, 6) arranged on both sides of the catalyst-coated membrane and a sealing frame (40), wherein, The sealing frame (40) is arranged around the catalyst coating film (100) and the diffusion layers (5, 6), wherein the sealing frame (40) has a step (45), and the catalyst coating film (100) is placed on the step (45). The catalyst coating film (100) is positioned within the sealing frame (40) by means of at least one positioning pin (50) arranged at the step (45).

2. The electrochemical battery (1) according to claim 1, characterized in that, The positioning pin (50) works in conjunction with the recess (110) constructed in the catalyst coating film (100).

3. The electrochemical battery (1) according to claim 1 or 2, characterized in that, The catalyst coating film (100) includes a film (2) and electrode layers (3, 4) arranged on both sides of the film, wherein the electrode layers (3, 4) are arranged on the film (2) only by means of an active surface (120), wherein the active surface (120) is defined by the inner periphery (49) of the sealing frame (40).

4. The electrochemical battery (1) according to claim 1 or 2, characterized in that, At least two locating pins (50) work together with a recess (110), wherein the two locating pins (50) are cylindrical, and the two recesses are elliptical, wherein the elliptical direction of the first recess (110a) is orthogonal to the elliptical direction of the second recess (110b).

5. The electrochemical battery (1) according to claim 1 or 2, characterized in that, The positioning pin (50) is materially locked to the sealing frame (40).

6. The electrochemical battery (1) according to claim 1 or 2, characterized in that, One of the diffusion layers (6) is also positioned within the sealing frame (40) by means of the locating pin (50).

7. The electrochemical battery (1) according to claim 6, characterized in that, The diffusion layer (6) has a flow structure toward the catalyst coating film (100).

8. The electrochemical battery (1) according to claim 1 or 2, characterized in that, The electrochemical cell (1) is an electrolytic cell.

9. The electrochemical battery (1) according to claim 8, characterized in that, The electrochemical cell (1) is a PEM electrolytic cell.

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