Cell stack fixing device for fixing a cell stack of a fuel cell and / or an electrolyzer during a separation process

Abstract

Cell stack fixing device (12; 12') for fixing a cell stack (16), in particular an electrochemical cell, during a separation process of adhering cell layers of the cell stack (16), in which a separating element (14) is passed between the adhering cell layers of the cell stack (16) through the, in particular the entire, cell stack, comprising a cell stack receiving unit (18) for receiving the cell stack (16) and a fixing unit (20; 20') which is configured to press the received cell stack (16) against the cell stack receiving unit (18) at different fixing areas (22) in the stack direction (24) depending on a relative position of the separating element (14) to the received cell stack (16) in order to keep the received cell stack (16) fixed during the, in particular the entire, passing of the separating element (14).

Description

State of the art

[0001] The invention relates to a cell stack fixing device for fixing a cell stack, in particular an electrochemical cell, during a separation process of adhering cell layers of the cell stack, and a cell stack fixing system with such a cell stack fixing device and a separation element, as well as the use of such a cell stack fixing device and / or such a cell stack fixing system for fixing a cell stack and a method for fixing a cell stack.

[0002] When recycling a wide variety of products such as packaging, electronic waste, etc., the products are typically shredded or ground in an "undefined" manner. Afterwards, the valuable fractions are separated from the less valuable ones and processed further.

[0003] Fuel cell stacks consist of membrane electrode assemblies (MEAs), which comprise membranes, gas diffusion layers (GDLs), and sealing frames, as well as bipolar plates (BPPs), which are typically made of sheet steel or milled graphite plates. These two components—MEAs and BPPs—are stacked alternately on top of each other. A typical automotive fuel cell stack with approximately 100 kW of power consists of 350 to 400 BPPs and an equal number of MEAs. Depending on the product design, the components are increasingly bonded together by the seals or the GDLs as operating hours increase.

[0004] The recycling of fuel cell stacks follows the procedure described in the introduction, which has several disadvantages. First, the MEAs (Metal Energy Elements) are difficult to separate from the BPPs (Bipolar Plate Components) for recycling or remanufacturing due to increasing adhesion and corrosion. This results in valuable particles or dust adhering to the bipolar plate fragments, being sorted out along with them, and thus irretrievably lost. Remanufacturing, for example, of bipolar plates is impossible due to the destructive shredding process. Furthermore, an undefined disassembly process for recycling poses the risk of significant losses of valuable materials.

[0005] Separating adhering cell layers of a cell stack can be achieved by passing a separating element / tool, e.g., a wire or thread, between the adhering cell layers, through the entire cell stack. However, depending on the separating element, this can become problematic if... - the cell stack lies loosely on the work surface and is therefore movable as a whole or as a partially detachable sub-stack, and / or - the uppermost, already partially detached cell layer shifts undefinedly as long as the separating element beneath it is still moving, and / or - there is a deflection of the cell stack in one or more directions, as larger-area separating elements such as a wire or cord, which must be threaded over the entire length or width of the cell stack, can no longer be used, so that the separation process is not smooth or not possible at all. Disclosure of the invention

[0006] The present invention relates to a cell stack fixing device for fixing a cell stack, in particular an electrochemical cell, during a separation process of adhering cell layers of the cell stack, in which a separating element is passed between the adhering cell layers of the cell stack through the, in particular the entire, cell stack, comprising a cell stack receiving unit for receiving the cell stack and a fixing unit which is configured to press the received cell stack against the cell stack receiving unit at different fixing areas in the stack direction, depending on the relative position of the separating element to the received cell stack, in order to keep the received cell stack fixed during the, in particular the entire, passage of the separating element.

[0007] The present invention further relates to a cell stack fixing system comprising a cell stack fixing device as described above and a separating element, in particular mounted in a translationally movable manner, for carrying out the separation process.

[0008] The present invention also relates to the use of a cell stack fixing device and / or a cell stack fixing system described above for fixing a cell stack, in particular an electrochemical cell, during a separation process of adhering cell layers of the cell stack, in which a separating element is passed between the adhering cell layers of the cell stack through the, in particular the entire, cell stack.

[0009] The present invention further relates to a method for fixing a cell stack, in particular an electrochemical cell, during a separation process of adhering cell layers of the cell stack, in which a separating element is passed between the adhering cell layers of the cell stack through the, in particular the entire, cell stack, wherein a fixing unit presses the cell stack received in a cell stack receiving unit against the cell stack receiving unit at different fixing areas in the stack direction, depending on a relative position of the separating element to the received cell stack, in order to keep the received cell stack fixed during the, in particular the entire, passing of the separating element.

[0010] Since the cell stack is preferably disassembled layer by layer from top to bottom, a fixed clamping device that presses the cell stack downwards across its entire surface is not suitable. Therefore, according to the invention, a cell stack fixing device is proposed in which a fixing unit presses the cell stack at different fixing points in the stack direction, depending on the relative position of the separating element to the cell stack being picked up, in order to hold it fixed during, and in particular the entire, passage of the separating element. In other words, the fixing points, i.e., the points at which the fixing unit presses the cell stack, change or move depending on the relative position of the separating tool.

[0011] This provides a "dynamic" or movable clamping mechanism that, on the one hand, adequately secures the cell stack against displacement and prevents any curvature of the cell stack, and on the other hand, does not impede the use or movement of the separating element / separation tool. This is achieved by the clamping unit applying pressure, depending on the relative position of the separating element, in such a way that pressure is only applied where the separating element is not obstructed during its passage. It is irrelevant whether the separating element is guided manually or moved automatically. Thus, disassembly is simple, quick, and smooth using the appropriate separating element, both manually and automatically.

[0012] In the context of the present invention, "passing through" refers in particular to passing the separating element continuously from one side of the cell stack to an opposite side of the cell stack.

[0013] Within the scope of the present invention, an electrochemical cell comprises, in particular, a fuel cell and / or an electrolysis cell and / or a battery cell. It should be noted that the cell stack can also be that of a cooler or heat exchanger without departing from the scope of the present invention.

[0014] Within the scope of the present invention, a cell stack fixing device is understood to be a device designed and dimensioned to fix a cell stack, in particular an electrochemical cell, during a separation process of adhering cell layers of the cell stack, in which a separating element is passed through the cell stack, in particular the entire cell stack, between the adhering cell layers. A cell layer of the cell stack may comprise or consist of a membrane electrode assembly (MEA) or a bipolar plate (BPP). Accordingly, the cell stack may, for example, comprise 700 to 1000 cell layers and have 350 to 500 BPPs and 350 to 500 MEAs.

[0015] The cell stacking unit can be designed, for example, as a worktable or worktop. The cell stacking unit can be height-adjustable.

[0016] The fixing unit is designed to press the cell stack against the cell stack receiving unit at different fixing areas in the stack direction, depending on the relative position of the separating element to the cell stack. It is particularly advantageous if the fixing unit is designed such that, depending on the relative position of the separating element to the cell stack, it only presses at fixing areas where the separating element is absent. Furthermore, it is particularly advantageous if the fixing unit is designed such that it always presses against the cell stack at at least one fixing area during the entire passage of the separating element, in order to keep the cell stack fixed throughout this entire passage.

[0017] In the context of the present invention, a relative position shall be understood to mean the relative position, in particular the linear position of the separating element transverse to the stacking direction, i.e. in the cell layer plane.

[0018] In the context of the present invention, a fixing area shall be understood to be the effective area or pressure area of ​​the fixing unit on the cell stack, which understandably includes not only the pressure point itself, but also the surrounding affected area.

[0019] It is advantageous if the fixing unit for pressing the cell stack against the cell stack receiving unit has at least one fixing element that is mounted to be movable translationally / linearly relative to the cell stack receiving unit.

[0020] In one embodiment, the at least one fixing element can be designed as at least one pressure roller, which is rollable on the cell stack to press it against the cell stack receiving unit at different fixing areas. The at least one pressure roller can be spring-loaded or actively controlled to exert pressure. Advantageously, the fixing unit can have a carrier mounted for translational / linear movement or a rail-guided carrier, on which the at least one pressure roller and a separating element receiving unit for receiving the separating element are arranged. The carrier can be height-adjustable.

[0021] It is further advantageous if at least one pressure roller is arranged in front of the separating element in a direction of movement intended for that element. This allows for a very simple provision of a fixing unit in which a pressure roller moves at a constant distance from the separating element and always presses the cell stack in front of the separating element against the cell stack receiving unit in the stacking direction.

[0022] Additionally, it is advantageous if at least one further pressure roller is arranged behind the separating element in the intended direction of movement. This measure ensures that the cell stack remains fixed throughout the entire passage of the separating element, even after the front pressure roller has left the cell stack.

[0023] In a further embodiment, the fixing unit can have at least two fixing elements designed as extendable plungers, wherein the at least two plungers can be extended in the stacking direction of the cell stack against the cell stack in order to press it against the cell stack receiving unit at different fixing areas. The plunger can be designed as a punch or a pin. Advantageously, the fixing unit can have a plurality of extendable plungers, which are arranged spaced apart from one another over a cell stack surface of the cell stack, in particular along a line or a two-dimensional pattern.

[0024] It is further advantageous if the extendable plungers can be controlled depending on the relative position of the separating element to the cell stack being received, such that only plungers press against the cell stack under which the separating element is absent, and / or at least one plunger always presses against the cell stack during the entire passage of the separating element in order to keep it fixed during the entire passage of the separating element.

[0025] Furthermore, it is advantageous if a sensor unit, particularly an optical one, is provided to determine the relative position of the separating element to the cell stack being recorded. The sensor unit can, for example, be designed as a contact sensor or a camera. It is also advantageous if a control unit is provided to control the fixing unit and / or fixing elements depending on the determined relative position.

[0026] It is therefore also conceivable that a manual disassembly process could be monitored by, for example, one or more optical sensor units, especially cameras, and that the relative position of the moving separating element could be continuously determined. This would allow for dynamic fixation of the cell stack even during manual disassembly, enabling the worker to concentrate solely on the disassembly itself.

[0027] The separating element is preferably mounted in a translationally / linearly movable manner or guided by rails. The separating element can be arranged on a support, in particular a height-adjustable one.

[0028] The separating element advantageously comprises at least one wire and / or thread, and in particular a plurality of wires and / or threads or cords / yarns arranged parallel to one another. In other words, for example, a plurality of parallel wires or threads can be arranged as separating elements in a frame-shaped separating element receiving unit, which, when inserted into the cell stack, thread themselves into the spaces between the cell layers to be separated. The wires and / or threads can be spaced apart from one another along a stacking direction. The number of wires and / or threads and / or the spacing between them is / are adapted to the cell stack and, if applicable, the respective manufacturing tolerances and geometric component tolerances. The spacing can be fixed and unchangeable. However, it is advantageous if the spacing is adjustable. Drawings

[0029] The invention is explained in more detail below with reference to the accompanying drawings. These show: Fig. 1 a schematic representation of a cell stack fixing system with an embodiment of a cell stack fixing device; Fig. 2 a schematic representation of a cell stack fixing system with a further embodiment of a cell stack fixing device; and Fig. 3 a flowchart of a process for fixing a cell stack, in particular an electrochemical cell, during a separation process of adhering cell layers of the cell stack.

[0030] In the following description of advantageous embodiments of the present invention, the same or similar reference numerals are used for the elements shown in the various figures and having a similar effect, without repeating these elements.

[0031] Fig. 1 and Fig. Figure 2 shows advantageous embodiments of a cell stack fixing system, which in their entirety are provided with the reference numerals 10 and 10'.

[0032] The cell stack fixing system 10 made of Fig. Figure 1 shows an embodiment of a cell stack fixing device 12 and separating elements 14.

[0033] The cell stack fixing device 12 is designed to fix a cell stack 16, in particular a fuel cell (not shown), during a separation process of adhering cell layers of the cell stack 16, in which the separating elements 14 are passed through the entire cell stack 16 between the adhering cell layers. For this purpose, the cell stack fixing device 12 has a cell stack receiving unit 18 designed as a worktable 18 for receiving the cell stack 16 and a fixing unit 20.

[0034] The fixing unit 20 is designed to press the cell stack 16 against the cell stack receiving unit 18 at different fixing areas 22 in the stack direction 24, depending on the relative position of the separating element 14 to the cell stack 16, in order to keep the cell stack 16 fixed during, and in particular throughout, the passage of the separating element 14. Furthermore, the fixing unit 20 is designed such that, depending on the relative position of the separating element 14 to the cell stack 16, it only presses at fixing areas 22 where the separating element 14 is absent.

[0035] To press the cell stack 16 against the cell stack receiving unit 18, the fixing unit 20 has a translationally movable carrier 26 on which two fixing elements 28 designed as pressure rollers 28 and a frame-shaped separating element receiving unit 30 for receiving the separating elements 14 are arranged.

[0036] The pressure rollers 28 are rollable on the cell stack 16 to press it against the cell stack receiving unit 18 at different fixing areas 22. In this arrangement, one of the pressure rollers 28 is positioned in front of the separating elements 14 in the intended direction of movement 32, and the other pressure roller 28 is positioned behind the separating elements 14 in the intended direction of movement 32, so that at least one of the pressure rollers 28 is always pressing against the cell stack 16 at a fixing area 22 during the entire passage of the separating element.

[0037] The separating elements 14 comprise a plurality of parallel-tensioned wires 14, which are arranged in the frame-shaped separating element receiving unit 30 and, when inserted into the cell stack 16, thread themselves into the spaces between the cell layers to be separated. The wires 14 are arranged at uniform intervals from one another along the stacking direction 24.

[0038] The cell stack fixing system 10' made of Fig. 2 shows a further embodiment of a cell stack fixing device 12' and separating elements 14.

[0039] In comparison to the embodiment from Fig. 1 The cell stack fixing device 12' has a fixing unit 20' with three fixing elements 28', which are designed as extendable plungers 28'. The extendable plungers 28' are arranged spaced apart from each other along a line over a cell stack surface of the cell stack 16.

[0040] The extendable plungers 28' can be extended in the stacking direction 24 of the cell stack 16 against the cell stack 16 in order to press it against the cell stack receiving unit 18 at different fixing points 22, depending on the relative position of the separating elements 14 to the cell stack 16. The plungers 28' can be controlled, depending on the relative position of the separating elements 14 to the cell stack being received 16, such that only plungers 28' under which the separating elements 14 are absent press against the cell stack 16, and that at least one plunger 28' always presses against the cell stack 16 during the entire passage of the separating elements 14, in order to hold it fixed throughout the entire passage of the separating elements 14.

[0041] The relative position of the separating elements 14 is determined by means of a (not shown) sensor unit, wherein a (not shown) control unit controls the plungers 28' depending on the determined relative position.

[0042] Fig.Figure 3 shows a flowchart of a method 100 for fixing a cell stack 16, in particular an electrochemical cell, during a separation process of adhering cell layers of the cell stack 16, in which a separating element 14 is passed through the entire cell stack 16 between the adhering cell layers of the cell stack 16. The method 100 comprises a step of receiving 102 the cell stack 16 in a cell stack receiving unit 18. The method 100 further comprises a step of pressing 104 the received cell stack 16 against the cell stack receiving unit 18 at different fixing areas 22 in the stack direction 24, depending on a relative position of the separating element 14 to the received cell stack 16, by means of a fixing unit 20, 20', in order to keep the received cell stack 16 fixed during, in particular throughout, the passage of the separating element 14.

[0043] If an embodiment includes an “and / or” connection between a first feature and a second feature, this is to be read as meaning that the embodiment according to one embodiment has both the first feature and the second feature, and according to another embodiment either only the first feature or only the second feature.

Claims

[1] Cell stack fixing device (12; 12') for fixing a cell stack (16), in particular an electrochemical cell, during a separation process of adhering cell layers of the cell stack (16), in which a separating element (14) is passed between the adhering cell layers of the cell stack (16) through the, in particular the entire, cell stack, comprising a cell stack receiving unit (18) for receiving the cell stack (16) and a fixing unit (20; 20') which is configured to press the received cell stack (16) against the cell stack receiving unit (18) at different fixing areas (22) in the stack direction (24) depending on a relative position of the separating element (14) to the received cell stack (16) in order to keep the received cell stack (16) fixed during the, in particular the entire, passing of the separating element (14). [2] Cell stack fixing device (12; 12') according to claim 1, characterized by, that the fixing unit (20; 20') is designed such that, depending on the relative position of the separating element (14) to the cell stack (16) taken up, it only presses on fixing areas (22) under which the separating element (14) is absent. [3] Cell stack fixing device (12; 12') according to claim 1 or 2, characterized by , that the fixing unit (20; 20') is designed such that it always presses against the cell stack (16) at least at one fixing area (22) during the entire passage of the separating element (14). [4] Cell stack fixing device (12; 12') according to one of the preceding claims, characterized by , that the fixing unit (20; 20') for pressing the cell stack (16) against the cell stack receiving unit (18) has at least one fixing element (28; 28') mounted translationally movable relative to the cell stack receiving unit (18). [5] Cell stack fixing device (12) according to claim 4, characterized by, that at least one fixing element (28) is designed as at least one pressure roller (28) which is rollable on the cell stack (16) in order to press it against the cell stack receiving unit (18) at different fixing areas (22). [6] Cell stack fixing device (12) according to claim 5, characterized by that at least one pressure roller (28) is spring-loaded or actively controlled for applying pressure. [7] Cell stack fixing device (12) according to claim 5 or 6, characterized by , that the fixing unit (20) has a translationally movable support (26) on which at least one pressure roller (28) and a separating element receiving unit (30) for receiving the separating element (14) are arranged. [8] Cell stack fixing device (12) according to claim 7, characterized by, that at least one pressure roller (28) is arranged in a designated direction of movement (32) of the separating element (14) in front of the separating element (14), and in particular at least one further pressure roller (28) is arranged in the designated direction of movement (32) of the separating element (14) behind the separating element (14). [9] Cell stack fixing device (12') according to claim 4, characterized by , that the fixing unit (20') has at least two fixing elements (28') which are designed as extendable plungers (28'), wherein the at least two plungers (28') are extendable in the stacking direction (24) of the cell stack (16) against the cell stack (16) in order to press it against the cell stack receiving unit (18) at different fixing areas (22). [10] Cell stack fixing device (12') according to claim 9, characterized by, that the fixing unit (20') has a plurality of extendable plungers (28') which are spaced apart from each other over a cell stack surface of the cell stack (16), in particular along a line or a two-dimensional pattern. [11] Cell stack fixing device (12') according to claim 9 or 10, characterized by , that the extendable plungers (28') can be controlled depending on the relative position of the separating element (14) to the cell stack (16) being received, such that only plungers (28') press against the cell stack under which the separating element (14) is absent, and / or that at least one plunger (28') always presses against the cell stack (16) during the entire passage of the separating element (14) in order to keep it fixed during the entire passage of the separating element (14). [12] Cell stack fixing device (12; 12') according to one of the preceding claims, characterized by a sensor unit, in particular an optical sensor unit, for determining the relative position of the separating element (14) to the cell stack (16) received, and in particular a control unit for controlling the fixing unit (20') and / or fixing elements (28') depending on the determined relative position. [13] Cell stack fixing system (10; 10') comprising a cell stack fixing device (12; 12') according to one of the preceding claims and a separating element (14) mounted in a translationally movable manner for carrying out the separation process. [14] Cell stack fixing system (10; 10') according to claim 13, characterized by , that the separating element (14) comprises at least one wire (14) and / or thread, in particular a plurality of wires (14) and / or threads arranged parallel to each other. [15] Use of a cell stack fixing device (12; 12') according to one of claims 1 to 12 and / or a cell stack fixing system (10; 10') according to claim 13 or 14 for fixing a cell stack (16), in particular an electrochemical cell, during a separation process of adhering cell layers of the cell stack (16), in which a separating element (14) is passed between the adhering cell layers of the cell stack (16) through the, in particular the entire, cell stack (16). [16] Method (100) for fixing a cell stack (16), in particular an electrochemical cell, during a separation process of adhering cell layers of the cell stack (16), in which a separating element (14) is passed between the adhering cell layers of the cell stack (16) through the, in particular the entire, cell stack, wherein a fixing unit (20; 20') presses the cell stack (16) received in a cell stack receiving unit (18) against the cell stack receiving unit (18) at different fixing areas (22) in the stack direction (24) depending on a relative position of the separating element (14) to the received cell stack (16) in order to keep the received cell stack (16) fixed during the, in particular the entire, passing of the separating element (14). [17] Method (100) according to claim 16, characterized by, that the relative position of the separating element (14) to the recorded cell stack (16) is determined by means of a sensor unit, in particular an optical sensor unit, and in particular the fixing unit (20') and / or fixing elements (28') are controlled by means of a control unit depending on the determined relative position.

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