Search

DE-102024210837-A1 - Separation device and method for separating bipolar plates and membrane electrode assemblies of a fuel cell stack

DE102024210837A1DE 102024210837 A1DE102024210837 A1DE 102024210837A1DE-102024210837-A1

Abstract

The invention relates to a separating device (10) for separating bipolar plates and membrane electrode assemblies (101) of a fuel cell stack (100), comprising a first separating tool (12) configured to partially separate a bipolar plate (101) connected to a membrane electrode assembly from a membrane electrode assembly or a membrane electrode assembly from a bipolar plate (101) by forming an initial gap between the bipolar plate (101) and the membrane electrode assembly, and a second separating tool (26) configured to penetrate the initial gap formed by the first separating tool (12).

Inventors

  • Manuel Beuttler
  • Ben Keller
  • Jochen Straehle
  • Benjamin Neumaier
  • Guenter Holzhaeuser
  • Bernd Beutel
  • Jan Patrick Lerner

Assignees

  • Robert Bosch Gesellschaft mit beschränkter Haftung

Dates

Publication Date
20260513
Application Date
20241112

Claims (13)

  1. Separating device (10) for separating cell layers (101) of a cell stack (100), in particular bipolar plates (101) and membrane electrode assemblies of a cell stack (100) of an electrochemical cell, preferably of a fuel cell stack (100) of a fuel cell, comprising a first separating tool (12) configured to selectively separate the cell layers (101), in particular a bipolar plate (101) connected to a membrane electrode assembly from a membrane electrode assembly or a membrane electrode assembly from a bipolar plate (101) by forming an initial gap between the bipolar plate (101) and the membrane electrode assembly, and a second separating tool (26) configured to penetrate the initial gap formed by the first separating tool (12) and to separate the cell layers (101), in particular a bipolar plate (101) from the membrane electrode assembly or the membrane electrode assembly from the to separate the bipolar plate (101) at least largely, in particular almost completely or completely, from each other by moving the second separating tool (26) in a feed motion.
  2. Separating device according Claim 1 , characterized in that the second separating tool (26) has a separating body (30) which has a wedge-shaped cross-section at least in some areas.
  3. Separating device according Claim 2 , characterized in that the wedge-shaped cross-section has a separating surface (36) extending at an oblique angle (γ) to a bottom surface (34) for interaction with an upper cell layer (101), in particular an upper bipolar plate (101) or the membrane electrode unit.
  4. Separating device according Claim 3 , characterized in that the oblique angle (γ) is between greater than or equal to 20° and less than or equal to 40°, preferably 30°.
  5. Separating device according to one of the Claims 2 until 4 , characterized in that the separating body (30) is designed in a strip-like shape with a constant cross-section and has a length (c) that corresponds at least to a width (B) of the cell layers (101) to be separated from each other, in particular bipolar plates (101), and that a fastening section (32) for fastening the second separating tool (26) to a drive mechanism (28) is attached to the separating body (30).
  6. Separating device according to one of the Claims 1 until 5 , characterized in that the second cutting tool (26) is made of steel, in particular stainless steel.
  7. Separating device according to one of the Claims 1 until 6 , characterized in that the first separating tool (12) is knife-shaped with a knife tip (22) for penetrating between one of the cell layers (101), in particular the bipolar plate (101) and the membrane electrode unit, and has a width (b) that is less than the width (B) of the cell layer (101), in particular the bipolar plate (101) and the membrane electrode unit.
  8. Separating device according Claim 7 , characterized in that the first cutting tool (12) is connected to a drive mechanism (14) which is designed to move the first cutting tool (12) perpendicular to a first feed direction of the first cutting tool (12) in the direction of a second feed direction of the first cutting tool (12) in order to form the initial gap.
  9. Separating device according Claim 8 , characterized in that the first separating tool (12) is additionally arranged to be raised and lowered perpendicular to the two feed directions.
  10. Method for separating cell layers (101) of a cell stack (100), in particular bipolar plates (101) and membrane electrode assemblies of a cell stack (100) of an electrochemical cell, preferably of a fuel cell stack (100) of a fuel cell, in particular by means of a separation device (10) according to one of the Claims 1 until 9 is designed, comprising at least the following steps: - Penetration of a first separation tool (12) between the cell layers (101), in particular a bipolar plate (101) and a membrane electrode assembly to create an initial gap; - Penetration of a second separation tool (26) into the initial gap and movement of the second separation tool (26) between the cell layers (101), in particular the bipolar plate (101) and the membrane electrode assembly in the direction of the side of the cell stack, in particular the fuel cell stack (101) facing away from the initial gap, until preferably complete separation of the cell layers (101), in particular the bipolar plate (101) and the membrane electrode assembly.
  11. Procedure according to Claim 10 , characterized in that the first separating tool (12) for forming the initial gap initially extends over a partial area of a width (B) and a length (L) of the cell layers (101), in particular the bipolar plate (101), between the bipolar plate (101) and the membrane electrode unit in the direction in a first feed direction and subsequently in a second direction perpendicular to the first feed direction in the plane of the cell layer (101), in particular bipolar plate (101), to form the initial gap over the entire width of the cell layer (101), in particular bipolar plate (101) or the membrane electrode unit.
  12. Procedure according to Claim 10 or 11 , characterized in that the initial gap is enlarged by raising the first separating tool (12) in a direction perpendicular to the plane of the cell layers (101), in particular bipolar plates (101), and the second separating tool (26) is moved into the initial gap below the first separating tool (12).
  13. Procedure according to one of the Claims 10 until 12 , characterized in that the second separating tool (26) is moved above or below a lower cell layer (101), in particular a membrane electrode assembly, wherein a separating surface (36) of the second separating tool (26) interacts with the upper cell layer (101), in particular the upper bipolar plate (101) or the membrane electrode assembly, and separates it from the membrane electrode assembly or the lower bipolar plate (101).

Description

Technical field The invention relates to a separation device for separating bipolar plates and membrane electrode assemblies of a fuel cell stack, characterized by a particularly safe separation process that is mechanically gentle on the bipolar plates and membrane electrode assemblies, especially during automated separation. Furthermore, the invention relates to a method for separating two bipolar plates connected by an interposed membrane electrode assembly, as well as membrane electrode assemblies, which enables a particularly gentle separation process. State of the art Within the framework of alternative drive concepts, hydrogen drives are known, for example, for commercial vehicles that use fuel cell stacks as part of the energy conversion system from chemical to electrical energy. Such a fuel cell stack typically consists of a large number of fuel cells arranged one above the other. Each fuel cell, in turn, consists of two bipolar plates and a membrane electrode assembly (MEA) located between the bipolar plates. The MEA is mechanically connected to the respective bipolar plate via sealing elements and sealed against it. To replace or recycle components within fuel cell stacks, for example, after the end of their service life or if individual cells are damaged, it is necessary to separate the bipolar plates and membrane electrode assemblies of the fuel cell stack. For this reason, corresponding devices are already known in the prior art. For example, it is known from the EP 1 478 043 A1 It is known to insert a strip-shaped, wedge-shaped separation tool from opposite sides of the fuel cell stack. This tool engages in a gap between two superimposed bipolar plates and separates the bipolar plates by moving the two tools relative to each other. The known separation tool has a length that extends across the entire width of the fuel cells or the aforementioned gap between the bipolar plates. From the US 2020/0373590 A1 Furthermore, separation tools acting on the fuel cell stack from opposite sides are also known, which in plan view are fork-shaped with two projections or prongs spaced apart from each other. In both documents mentioned, the separation tools are identically designed and are typically moved to about the middle of the fuel cell stack to enable (complete) separation of the bipolar plates. Disclosure of the invention The separation device according to the invention for separating cell layers of a cell stack, in particular bipolar plates and membrane electrode units of a cell stack of an electrochemical cell, preferably of a fuel cell stack of a fuel cell with the features of claim 1, makes it possible to separate the bipolar plates and membrane electrode units connected to each other by sealing elements in a particularly simple and process-reliable way without damaging the bipolar plates and membrane electrode units. The cell layers are preferably bipolar plates and/or membrane electrode assemblies. The cell stack is preferably a cell stack or a fuel cell stack. 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. The invention is based on the idea – in contrast to the prior art mentioned above – of using two differently designed separation tools serving different purposes, which are moved from the same side of the fuel cell stack between the bipolar plates and membrane electrode assemblies to be separated. While the first separation tool is designed to create an initial gap between two superimposed bipolar plates and a membrane electrode assembly to allow the subsequent insertion of a second separation tool, the second separation tool is optimized to enable complete separation of the bipolar plates or membrane electrode assemblies from the bipolar plates when an initial gap already exists. In light of the above explanations, a separating device according to the invention for separating bipolar plates and membrane electrode units of a fuel cell stack has the features of Claim 1 describes a first separating tool configured to partially separate a bipolar plate connected to a membrane electrode assembly from the membrane electrode assembly, or a membrane electrode assembly from a bipolar plate, by forming an initial gap between the bipolar plate and the membrane electrode assembly. Furthermore, a second separating tool is provided, configured to penetrate the initial gap formed by the first separating tool and to at least nearly completely separate the bipolar plate from the membrane electrode assembly, or the membrane electrode assembly from the bipolar plate, by moving the second separating tool in a feed motion. Advantageous further developments of the separation device according to the invention for separating bipolar plates and membrane electrode unit