Method for sealing an electrolytic cell and sealed electrolytic cell

Abstract

The present invention relates to a method for sealing an electrolytic cell comprising an anode half-cell (2) and a cathode half-cell (3) formed by at least two cell elements (4, 5) and a sheet-like separator (6) separating the half-cells (2, 3) from one another, the method comprising the steps of providing the two cell elements (4, 5) and the sheet-like separator (6), interposing the separator (6) between the two cell elements (4, 5) and sealing the separator (6) on each side and the two cell elements in the rim regions (9, 10) of each of the cell elements (4, 5). The present invention further relates to a sealed electrolysis cell obtainable by this method, comprising interposing a layer of a sealant (7, 8) between the cell elements (4, 5) and the interposed separator (6), and sealing the electrolysis cell (1), wherein a force (F) is applied to the cell elements (4, 5) compressing the rim areas (9, 10), the sealant (7, 8) being an electrically insulating material, and during the sealing step the state of the sealant is changed from a liquid state to a solid state creating an adhesive bond between the cell elements (4, 5) and the interposed separator (6) by the sealant (7, 8), the force (F) being relaxed after the sealant has solidified.

Description

Technical Field

[0001] The present invention relates to a method for sealing an electrolytic cell as described in the preamble of claim 1 and a sealed electrolytic cell as described in the preamble of claim 7.

Background Art

[0002] Bipolar electrolytic cells for the large-scale production of hydrogen and / or chlorine (i.e., in the megawatt range) can be classified into two main design categories, namely filter press designs and single element designs.

[0003] In conventional filter press electrolytic cells, to seal all the electrolytic cells at once, a stack of multiple elements is formed in a cell rack by interposing sheet-like separators and gaskets between adjacent elements and compressing the entire stack. In a filter press designed electrolytic cell, each cell element forms an anode half-cell of one electrolytic cell and a cathode half-cell of an adjacent electrolytic cell in the stack. The sealing force for all cells is provided by tie rods extending along the stack.

[0004] In a single element designed electrolytic cell, each electrolytic cell is a separately sealed unit. Each electrolytic cell comprises two cell elements in the form of half-shells, and the two cell elements are bolted in the rim regions of the two cell elements with a separator and a gasket interposed therebetween. Thus, each cell element forms one half-cell of the electrolytic cell, and the half-cells are separated by a separator. The sealing force for sealing the electrolytic cell is provided by a plurality of bolts distributed circumferentially along the rim region of the cell element.

[0005] In both design options, the separator can be an ion-exchange membrane or a porous diaphragm, depending on the intended purpose of the electrolytic cell. Furthermore, in both design options, short circuits between the two cell elements forming each electrolytic cell should be reliably prevented; therefore, in addition to the gasket, at least one layer of electrical insulating material is usually interposed in the rim region before sealing.

[0006] U.S. Patent Application Publication No. 2011 / 0259735 provides examples of filter press and single-element designs for bipolar electrolytic cells.

[0007] Known types of bipolar electrolytic cells have the disadvantage of requiring considerable effort to assemble in order to seal the cells. In filter press electrolytic cells, the sealing force for all cells is provided by the same set of tie rods, but sealing the cell stack is complex and time-consuming because all separators, gaskets, and insulating layers must be precisely positioned at once. Single-element electrolytic cells require numerous bolted connections for each element to safely prevent leakage during operation. Furthermore, the spatial requirements of the structural elements necessary to provide the sealing force reduce the space available for the cell volume, and in single-element designs in particular, conventional sealing structures set a lower limit on the thickness of each element. [Prior art documents] [Patent Documents]

[0008] [Patent Document 1] U.S. Patent Application Publication No. 2011 / 0259735 [Overview of the Initiative] [Problems that the invention aims to solve]

[0009] The object of the present invention is to provide a method for sealing an electrolytic cell and a sealed electrolytic cell that requires less assembly effort and reduces the spatial requirements of the sealing structure. [Means for solving the problem]

[0010] This objective is achieved by a method for sealing an electrolytic cell according to the features of claim 1, and a sealed electrolytic cell having the features of claim 7.

[0011] This specification provides a method for sealing an electrolytic cell comprising an anode half-cell and a cathode half-cell formed by at least two cell elements, and a sheet-like separator separating the half-cells from each other, the method being as follows: Steps to provide two cell elements and a sheet-like separator, - The steps of interposing a separator between two cell elements and interposing a layer of sealing material between each surface of the separator and the two cell elements in the rim region of each cell element. - A step of sealing an electrolytic cell, wherein a force is applied to the cell element to compress the rim region. Includes.

[0012] According to the present invention, the encapsulant is an electrical insulating material, and during the encapsulation step, the state of the encapsulant is changed from a liquid state to a solid state, creating an adhesive bond between the cell element and the interposed separator. The force is relieved after the encapsulant has solidified.

[0013] By sealing electrolytic cells using adhesive bonding of cell elements, the need to place and fasten bolts is eliminated, thus simplifying cell assembly. Furthermore, the electrical insulating properties of the adhesive allow for the elimination of a separate insulating layer. The method according to the present invention is particularly well suited for the automated manufacturing of electrolytic cells. In addition, since the sealing force according to the present invention is provided by the adhesive bonding between the sealing material and the cell elements, it becomes possible to assemble filter press type electrolytic cells cell by cell. Therefore, an external force to compress the stack to seal the cells is no longer required. Furthermore, since external structural elements to maintain the sealing force are no longer required, the spatial requirements of the sealing structure of the present invention are particularly low, allowing for a further reduction in cell thickness.

[0014] In some embodiments, the sealant is a chemically curable adhesive or a solvent-based adhesive. Chemically curable and solvent-based adhesives have the advantage of being particularly strong adhesive bonds that can withstand high temperatures and / or harsh chemicals. When an adhesive is used as the sealant, the sealant layer is preferably interposed by applying the adhesive in a viscous liquid state to the rim regions of both cell elements.

[0015] In other embodiments, the sealing material is a thermoplastic material, and the step of sealing the electrolytic cell is: • Inputting energy into the sealing material to make it thermoplastic, • The sealing material is bonded to the cell element and the interposed separator while the sealing material is in a thermoplastic state. • Lowering the temperature of the sealing material to solidify it, Includes.

[0016] Thermoplastic materials have the advantage of providing the possibility of opening and resealing electrolytic cells in an easy and non-destructive manner. For maintenance, such as replacing separators, the rim region can be heated until the thermoplastic material becomes thermoplastic again, allowing the cell elements to be separated.

[0017] When a thermoplastic material is used as a sealant, the adhesive bond can be created in a two-step process in which a layer of sealant is first bonded to the cell elements, and then the two layers of sealant are bonded to each other and to the separator in the sealing step. The first bond may already be present, for example, when the two cell elements are provided, i.e., the cell elements are provided with a coating of thermoplastic material within their rim regions. Alternatively, the first bond may be created during the step of interposing the sealant or during the sealing step.

[0018] Thermoplastic materials can be brought into a thermoplastic state by different types of energy supply. In the simplest case, energy is input by heating the rim area. Another possible way of inputting energy is the heat welding of a layer of sealing material by ultrasound.

[0019] Particularly preferred for sealing an electrolytic cell is a thermoplastic material containing polypropylene (PP), particularly atactic polypropylene (PP-R), and / or polyvinyl chloride (PVC).

[0020] Preferably, the sealing step further includes folding the rim area of the cell element backward towards one side. By folding both rim areas backward towards the same side, for example, by 120° to 180°, a mechanical interlocking of the cell elements is achieved that further supports the sealing of the cell. In particular, the fold is advantageous in an electrolytic cell operated at elevated internal pressure because the fold releases the adhesive bond from pressure by shape locking.

[0021] In a preferred embodiment, the cell element is made of a metal sheet having a thickness of 0.8 mm or less. Preferred metals are nickel and / or titanium. With the sealing concept according to the invention, it is even conceivable to manufacture an electrolytic cell from a metal foil having a thickness of 0.2 mm or less.

[0022] The problem is further solved by a sealed electrolytic cell comprising an anode half-cell and a cathode half-cell formed by at least two cell elements, and a sheet-like separator separating the half-cells from each other. Each cell element has a rim area and is attached to each other in the rim area in an electrically insulated and sealed manner with a layer of sealing material interposed between each side of the separator and the two cell elements. According to the invention, the sealing material is a solidified liquid material that forms an adhesive bond between the cell elements and provides electrical insulation and sealing of the cell elements.

[0023] The main advantage of the sealed electrolytic cell of the present invention is that the sealing force is provided by an adhesive bond, and external structural elements for maintaining the sealing force can be omitted. Therefore, an electrolytic cell using this type of electrolytic cell can use the available space more effectively and operate the cell under lower mechanical stress. Furthermore, the sealing configuration no longer limits the possibility of designing an electrolytic cell with a reduced thickness.

[0024] In certain embodiments, the sealant is a chemically curable adhesive or a dried solvent-based adhesive.

[0025] In other embodiments, the sealant is a thermoplastic material. In particular, it is preferable that the sealant contains polypropylene (PP) and / or polyvinyl chloride (PVC).

[0026] In a preferred embodiment, the edges of the sheet-like separator are embedded in the solidified sealant. Therefore, the risk of leakage due to the capillary effect of the separator can also be avoided. This is particularly advantageous when a porous diaphragm is used as the separator, as it is known that a porous diaphragm can cause leakage problems due to capillary forces when the porous diaphragm extends from between the rim regions of the cell elements to the outside of the cell.

[0027] Furthermore, it is preferable that the rim region of the cell element is folded backward toward one side so as to provide a mechanical form of lock between the cell elements.

[0028] [[ID=…]] The cell element is preferably made of a metal sheet having a thickness of 0.8 mm or less, particularly 0.2 mm or less. Preferred metals are nickel and / or titanium. <0…]]

[0029] In particular, the present invention relates to an industrial-scale electrolytic cell. Therefore, the separator of the electrolytic cell according to the present invention preferably has an area of 0.5 m 2 ~4 m 2 Furthermore, the electrolytic cell is preferably configured with a current density of at least 3 kA / m 2 ​

[0030] Further advantages of the present invention are described below with respect to embodiments shown in the accompanying drawings. [Brief explanation of the drawing]

[0031] [Figure 1] A schematic flowchart illustrating the method of the present invention for sealing electrolytic cells is shown. [Figure 2A] A schematic diagram illustrates one step in the fabrication of a single-element type sealed electrolytic cell according to the present invention. [Figure 2B] Another step in the fabrication of a single-element type sealed electrolytic cell according to the present invention is schematically shown. [Figure 2C] Another step in the fabrication of a single-element type sealed electrolytic cell according to the present invention is schematically shown. [Figure 3A] A schematic diagram illustrates one step in the fabrication of a sealed electrolytic cell of the filter press type according to the present invention. [Figure 3B] Another step in the fabrication of a sealed electrolytic cell of the filter press type according to the present invention is schematically shown. [Modes for carrying out the invention]

[0032] In drawings, the same part is consistently identified by the same reference numeral and is therefore generally depicted and referenced only once.

[0033] Figure 1 shows a flow chart of method 100 for sealing an electrolytic cell, illustrating the sequence of steps in an abstract manner. Figure 2A shows the electrolytic cell in the state before the sealing step of the method, and Figure 2B shows one embodiment of the sealed electrolytic cell 1. Figure 2C shows a different embodiment of the sealed electrolytic cell 1 having a rearward-folded rim region. The method steps are described below with reference to Figures 1 and 2A through 2C.

[0034] According to the method of the present invention in step 110, two cell elements 4 and 5 and a sheet-like separator 6 are provided. In step 120, the separator 6 is interposed between the two cell elements 4 and 5, and layers of sealing material 7 and 8 are interposed between each surface of the separator 6 and the two cell elements 4 and 5 in the respective rim regions 9 and 10 of the cell elements 4 and 5. Figure 2A shows the electrolytic cell in the assembly stage after step 120.

[0035] In step 130, the electrolytic cell 1 is sealed, where a force F is applied to the cell elements 4 and 5 to compress the rim regions 9 and 10. The sealing materials 7 and 8 are electrical insulating materials, and during sealing step 130, the state of the sealing materials 7 and 8 is changed from a liquid state to a solid state, creating an adhesive bond between the cell elements 4 and 5 and the interposed separator 6. The force F is released after the sealing materials 7 and 8 have solidified. Figure 2B shows the sealed electrolytic cell 1 after step 130.

[0036] The sealing materials 7 and 8 may be chemically curable adhesives or solvent-based adhesives.

[0037] In the method shown in Figure 1, the encapsulants 7 and 8 are thermoplastic materials. Therefore, step 130 for encapsulating the electrolytic cell 1 further includes step 140 of inputting energy into the rim regions 9 and 10 to make the encapsulants 7 and 8 thermoplastic, step 150 of bonding the cell elements 4 and 5 with the interposed separator 6 while the encapsulants 7 and 8 are thermoplastic, and step 160 of lowering the temperature of the encapsulants 7 and 8 to solidify them. Preferably, the encapsulants 7 and 8 contain polypropylene (PP) and / or polyvinyl chloride (PVC).

[0038] For example, energy can be input by heating the rim regions 9, 10 to the temperature at which the sealant is in its thermoplastic state. Lowering the temperature of the sealants 7, 8 can be achieved, for example, by stabilizing the temperature at the ambient temperature or by actively cooling the rim regions 9, 10.

[0039] Preferably, as shown in Figure 1, the sealing step 130 further includes folding the rim regions 9 and 10 of the cell elements 4 and 5 backward relative to one side of the separator 170. The folding 170 may be performed either after or before the sealant has solidified. In particular, when using a chemically curable adhesive or a solvent-based adhesive, it is preferable that the folding 170 be performed before the adhesive has solidified. Figure 2C shows one embodiment of the sealed cell 1 after the folding step 170.

[0040] A sealed electrolytic cell 1 manufactured according to the method of the present invention is shown in Figure 2B. The sealed electrolytic cell 1 comprises an anode half cell 2 and a cathode half cell 3 formed by at least two cell elements 4 and 5, and a sheet-like separator 6 that separates the half cells 2 and 3 from each other.

[0041] Anode half-cell 2 and cathode half-cell 3 each contain an anode and a cathode (not shown). The anode and cathode may be joined together with their respective cell elements 4 and 5, or they may be configured as separate components.

[0042] Each of the cell elements 4 and 5 has a rim region 9 and 10, and is attached to each other in the rim regions 9 and 10 in a manner that is electrically insulated and sealed by interposing layers of sealing material 7 and 8 between each surface of the separator 6 and the two cell elements 4 and 5. The sealing material 7 and 8 of the sealed cell 1 is a solidified liquid material that forms an adhesive bond between the cell elements 4 and 5 and provides electrical insulation and sealing of the cell elements 4 and 5.

[0043] The solidified sealant is a chemically curing adhesive or a dried solvent-based adhesive. Alternatively, the sealant may be a thermoplastic material. In particular, the sealant may contain polypropylene (PP) and / or polyvinyl chloride (PVC).

[0044] As shown in Figure 2B, it is preferable that the edge 11 of the sheet-like separator 6 is embedded in the solidified sealant. Therefore, the sheet-like separator 6 is not confined to the outside of the cell through the rim regions 9 and 10, but is instead enclosed in a shape-fitting manner within the adhesive bond between the cell elements 4 and 5.

[0045] Cell elements 4 and 5 are preferably made from metal sheets having a thickness of 0.8 mm or less. In particular, the cell elements may be made from metal foil having a thickness of 0.1 mm or less. Preferred metals are nickel and titanium.

[0046] The electrolytic cell 1 is preferably configured for alkaline water electrolysis or chlor-alkali electrolysis.

[0047] Figure 2C shows one embodiment of a sealed electrolytic cell 11, in which the rim regions 9 and 10 of the cell elements 4 and 5 are folded backward toward one side. Thus, in all other respects, the description of the embodiment shown in Figure 2A is applicable to the embodiment shown in Figure 2B.

[0048] Embodiments shown in Figures 2B and 2C relate to a single-element electrolytic cell 1. The electrolytic cell 1 is configured as a separate unit and can be electrically connected in series by bringing the back surfaces of cell elements 4 and 5 into contact with adjacent cells. This allows for the construction of a stack of electrolytic cells 1, with a power supply located on the outside of the outermost cell of the stack.

[0049] Figures 3A and 3B show a filter press type method and one embodiment of a sealed cell 1. Each cell element 4, 5 provides an anode half cell 2 and a cathode half cell 3 for an adjacent cell. Multiple cell elements 4, 5 can be sealed one to one with one separator 6 interposed between each of them for a stack of filter press type electrolytic cells 1.

[0050] Therefore, in all other respects, the description of the embodiments shown in Figures 2A and 2B is applicable to the embodiments shown in Figures 3A and 3B. [Explanation of Symbols]

[0051] 1 electrolytic cell 2 Anode Half Cells 3 Cathode Half Cells 4, 5 cell elements 6 Separators 7, 8 Sealing material 9, 10 Rim area 11. Edge of the separator 100 Methods for sealing electrolytic cells Provides 110 cell elements and separators. 120 Separators and sealing materials are interposed between the cell elements. 130. Seal the electrolytic cell. 140 Input energy into the limb region 150 Combine cell elements and separators 160 Lower the temperature in the rim area 170 Fold the rim area F Compression force

Claims

1. A method for sealing an electrolytic cell (1) comprising an anode half cell (2) and a cathode half cell (3) formed by at least two cell elements (4, 5), and a sheet-like separator (6) separating the half cells (2, 3) from each other, wherein the method (100) is as follows - Step (110) of providing the two cell elements (4, 5) and the sheet-like separator (6), - Step (120) of interposing the separator (6) between the two cell elements (4, 5) and step (120) of interposing layers of sealing material (7, 8) between each surface of the separator (6) and the two cell elements (4, 5) in the respective rim regions (9, 10) of the cell elements (4, 5), - A sealing step (130) of the electrolytic cell (1), wherein a force (F) is applied to the cell elements (4, 5) to compress the rim regions (9, 10). In a method including, The sealing material (7, 8) is an electrical insulating material, and during the sealing step (130), the state of the sealing material (7, 8) is changed from a liquid state to a solid state, and the sealing material (7, 8) creates an adhesive bond between the cell elements (4, 5) and the interposed separator (6), and the force (F) is relieved when the sealing material (7, 8) solidifies. The sealing step (130) is - Folding the rim regions (9, 10) of the cell elements (4, 5) backward toward one side (170) A further comprising, method.

2. The method according to claim 1, characterized in that the sealing material (7, 8) is a chemically curable adhesive or a solvent-based adhesive.

3. The sealing material (7, 8) is a thermoplastic material, and the step (130) of sealing the electrolytic cell (1) is, - Energy is input to the sealing material (7, 8) to bring the sealing material (7, 8) into a thermoplastic state (140), - The sealing material (7, 8) is bonded to the cell element (4, 5) and the interposed separator (6) while the sealing material (7, 8) is in the thermoplastic state (150), - Lowering the temperature of the sealing material (7, 8) to solidify the sealing material (7, 8) (160), The method according to claim 1, characterized by including

4. The method according to claim 3, characterized in that the energy is input by heating or ultrasound.

5. The method according to claim 3, characterized in that the sealing material (7, 8) contains polypropylene (PP) and / or polyvinyl chloride (PVC).

6. The method according to any one of claims 1 to 5, characterized in that the cell elements (4, 5) are made of a metal sheet having a thickness of 0.8 mm or less.

7. The method according to any one of claims 1 to 5, characterized in that the cell elements (4, 5) are made of a metal sheet having a thickness of 0.2 mm or less.

8. A sealed electrolytic cell (1) comprising an anode half-cell (2) and a cathode half-cell (3) formed by at least two cell elements (4, 5), and a sheet-like separator (6) separating the half-cells (2, 3) from each other, wherein each of the cell elements (4, 5) has a rim region (9, 10), and layers of sealing material 7, 8 are interposed between each surface of the separator (6) and the two cell elements (4, 5), thereby attaching them to each other in the rim region (9, 10) in a manner that is electrically insulated and sealed, wherein the sealing material (7, 8) is a solidified liquid material that forms an adhesive bond between the cell elements (4, 5) and provides electrical insulation and sealing of the cell elements (4, 5). A sealed electrolytic cell (1) characterized in that the rim regions (9, 10) of the cell elements (4, 5) are folded backward toward one side.

9. The sealed electrolytic cell according to claim 8, characterized in that the sealing material (7, 8) is a chemically curing adhesive or a dried solvent-based adhesive.

10. The sealed electrolytic cell according to claim 8, characterized in that the sealing material (7, 8) is a thermoplastic material.

11. The sealed electrolytic cell according to claim 10, characterized in that the sealing material (7, 8) contains polypropylene (PP) and / or polyvinyl chloride (PVC).

12. The sealed electrolytic cell according to claim 8, characterized in that the edge (11) of the sheet-like separator (6) is embedded in the solidified sealing material (7, 8).

13. The sealed electrolytic cell according to any one of claims 8 to 12, characterized in that the cell elements (4, 5) are made of a metal sheet having a thickness of 0.8 mm or less.

14. The sealed electrolytic cell according to any one of claims 8 to 12, characterized in that the cell elements (4, 5) are made of a metal sheet having a thickness of 0.2 mm or less.

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