Clamping band for a stack assembly

Abstract

A clamping band (1) for maintaining compression of a fuel cell stack assembly, particularly a fuel cell stack assembly, comprising at least an elongated strip element (2) having a first end (4) and a second end, and at least one fastening element (6), wherein the at least one fastening element (6) includes at least one bolt portion (8) configured to be attached to a portion of the fuel cell stack assembly (2), wherein the fastening element (6) includes at least one mark (14) indicating the position and / or orientation of the fastening element (6).

Description

Technical Field

[0001] This invention relates to a fuel cell stack assembly. Background Technology

[0002] Typically, a fuel cell stack assembly (such as a fuel cell stack) includes a stack body comprising multiple individual cells stacked along a stacking direction. Each individual cell includes at least two plates, so-called flow field plates, which are stacked on top of each other and have a flow field on one side for reactants and a flow field on the other side for cooling fluids. Thus, the flow fields of adjacent plates form channels through which the corresponding fluids flow.

[0003] To prevent any fluid leakage and achieve a fluid seal in the fuel cell stack, the stack body is compressed along the stacking direction using compression elements. Typically, the stack body of the fuel cell stack assembly is clamped between two end plates. To maintain the compression of the stack assembly, clamping straps can be attached to a portion of the stack and / or wrapped around the stack body. The clamping straps may include a strip-shaped element of a defined length to define and maintain the stack body pressure, and fastening elements for attaching the clamping straps to the stack body. Thus, the fastening elements may be separate elements that can be permanently attached to the strip-shaped element.

[0004] However, due to the tension necessary to maintain compressibility, the strip elements and / or fasteners are subjected to strain and / or stress (such as shear forces). These forces can cause deterioration and / or wear of the connection between the strip elements and fasteners, ultimately leading to loss of compressibility and consequently fluid leakage. Summary of the Invention

[0005] Therefore, the object of the present invention is to provide a clamping band with improved service life and stability.

[0006] This objective is achieved by the clamping band according to claim 1.

[0007] Below, a clamping band for maintaining the compression of a fuel cell stack assembly is provided, particularly a clamping band for maintaining the compression of a fuel cell stack assembly. The clamping band includes at least an elongated strip element having a first end and a second end, and at least one fastening element for securing the strip element (4) to the fuel cell stack assembly, wherein the fastening element is a separate element that has been permanently attached to the strip element. For example, the fastening element may be welded, bonded, and / or riveted to a base element.

[0008] To ensure that the attachment between the fastening element and the strip element remains permanent even over a long service life and under large forces, it is necessary to ensure that the joint between the fastening element and the strip element does not bear excessive shear force. To this end, it is proposed to provide the fastening element with at least one alignment feature that defines the attachment orientation of the fastening element relative to the strip element, such that the fastening element is attached to the strip element in a predetermined position and / or in a predetermined orientation.

[0009] A fuel cell stack assembly, particularly a fuel cell stack assembly, may include at least a stack of power-generating cells having a plurality of individual cells stacked along a stacking direction, wherein preferably each individual cell is a single fuel cell including bipolar plates and a membrane electrode assembly. The stack assembly may also include a first end plate and a second end plate sandwiching the power-generating cell stack therebetween. For example, at least one of the end plates may have an opening in its side, the opening being configured to receive at least a portion of a fastening element.

[0010] Preferably, at least one fastening element is disposed at a first end and / or a second end of the strip element. The fastening element extends vertically from the strip element so that it can be inserted into an opening provided in a portion of the stack assembly, such as the side of an end plate. This has the advantage of avoiding over-compression of the stack assembly during assembly. More specifically, during assembly, the stack body is compressed at most to the height of the completed stack assembly, allowing the fastening element to be inserted into the corresponding opening. Therefore, the risk of damage to components of the stack body is reduced.

[0011] Preferably, the strip element has a predetermined length. More preferably, the length is suitable for providing the desired pressure of the fuel cell assembly under operating conditions. This allows for the determination of the applied pressure. For example, at least one compression element may be made of a metal plate.

[0012] As described above, to provide a clamping band with improved service life and stability, it is preferable to attach the fastening element to the strip element in a predetermined spatial orientation. The alignment feature used to provide the predetermined spatial orientation is preferably at least one mark indicating the position and / or orientation of the fastening element. The at least one mark can be a geometric and / or optical feature possessed by at least a portion of the fastening element. For example, the at least one mark can be an optical feature detectable visually and / or by means of a camera device, such as one or more lines, one or more dots, or one or more symbols, which can be coated on or engraved into the fastening element. The mark can also be a groove, notch, or protrusion. If the fastening element has a rounded surface area and / or a curved shape, the at least one mark can be a flat area, and / or if the fastening element has a flat surface area, the at least one mark can be a curved area.

[0013] According to another preferred embodiment, the fastening element has a base and a bolt portion, wherein the base is attached to a strip element and the bolt portion can be attached to a fuel cell assembly.

[0014] Preferably, the bolt portion may have a circular, rectangular, elliptical, triangular, or polygonal cross-section, and / or a blocky, conical, truncated conical, or pyramidal shape, and / or at least one chamfered edge. Furthermore, the opening formed in a part of the fuel cell assembly and configured to receive the bolt portion may have a shape complementary to the bolt portion. This has the advantage of defining the position of the bolt portion within the opening. Additionally, the contact area between the opening and the bolt portion can be increased, which can lead to increased friction between the opening and the bolt portion, thereby fixing the position of the bolt portion within the opening.

[0015] Furthermore, the fastening element may include at least one positioning element configured to fix the position of the fastening element relative to the stack assembly. This reduces the risk of the fastening element becoming detached from the stack assembly due to vibration and / or other external forces. Preferably, the fastening element and / or bolt portion may include a through hole adapted to receive and / or interact with the positioning element. This allows the positioning element to be inserted through the through hole.

[0016] According to another embodiment, at least one fastening element further includes a base and a bolt portion as described above, wherein at least one mark is arranged on the bolt portion and / or the base. Since the mark indicates the predetermined position and / or orientation of the fastening element, it can also indicate the preferred installation state of the clamping band itself. This allows the clamping band to be installed in a manner that reduces the strain and / or shear force acting on the fastening element and / or the band element.

[0017] Furthermore, because the base is permanently fixed to the strip element, the height of the stack assembly can be maintained throughout its entire service life. For example, the base can be welded, bonded, and / or riveted to the strip element.

[0018] According to a preferred embodiment, at least the strip element and the base are made of metal, and the base is welded to the strip element. For example, resistance welding can be used to weld the base to the strip element. Welding allows a strong connection to be formed between the strip element and the base. However, under excessive shear force, the weld is prone to detachment. Therefore, the spatial orientation of the fastening element relative to the strip element is very important, which can be ensured by alignment features.

[0019] According to another embodiment, the base includes at least one welding protrusion for welding the base to the strip element, wherein at least one mark is configured to indicate the location of the at least one welding protrusion. The at least one welding protrusion may have an arcuate shape. The welding protrusion can be used to automatically weld the base to the strip element. Furthermore, the at least one welding protrusion allows for ensuring the use of consistent and / or reliable welding parameters. This has the advantage of more consistent weld shear strength.

[0020] Furthermore, by using at least one mark to identify at least one weld protrusion, it can be ensured that at least one weld protrusion is positioned in a predetermined location even during automated welding. Therefore, the consistency of the alignment of the weld protrusion with respect to the strip element (particularly the longitudinal direction of the strip element) can be improved.

[0021] Preferably, at least one weld protrusion is arranged such that it is at least partially aligned with the load direction of the clamping band. This improves the shear strength of the weld.

[0022] Preferably, the base includes two or more discrete weld protrusions. For example, the base may have four weld protrusions. Discrete weld protrusions can have the advantage of concentrated welding current, which allows for a more efficient welding process.

[0023] According to another embodiment, the plurality of welding protrusions are arranged such that there are more welding protrusions in the region subjected to higher loads than in the region subjected to lower loads.

[0024] Further preferred embodiments are defined in the dependent claims, as well as in the specification and drawings. Thus, elements described or shown in combination with other elements may exist alone or in combination with other elements without departing from the scope of protection. Attached Figure Description

[0025] Preferred embodiments of the invention are described below with reference to the accompanying drawings, which are merely illustrative and not intended to limit the scope of protection. The scope of protection is defined only by the appended claims.

[0026] Figure 1 This is a perspective view of the clamping band according to the embodiment; and

[0027] Figure 2 yes Figure 1 The top view of the clamping strap shown.

[0028] In the following text, elements with the same or similar functions are indicated by the same reference numerals. Detailed Implementation

[0029] Figure 1 and Figure 2A clamping band 1 for maintaining compression of a fuel cell stack assembly (particularly a fuel cell stack assembly) is shown. The clamping band 1 includes at least an elongated strip element 2 having a first end 4 and a second end (not shown), and a fastening element 6. The fastening element 6 includes a bolt portion 8 configured to be attached to a portion of the fuel cell stack assembly, and a base 10 through which the fastening element can be permanently attached to the strip element 6.

[0030] Fastening element 6 is arranged at the first end 4 of strip element 2 such that bolt portion 8 of fastening element 6 extends vertically from strip element 2. Bolt portion 8 can be inserted into an opening provided in a part of the stack assembly (such as the side of the end plate).

[0031] exist Figure 1 In the illustrated embodiment, the bolt portion 8 is substantially cylindrical, and the base 10 is circular. However, the bolt portion 8 and / or the base may have any other possible shape and / or cross-section. Furthermore, the fastening element 6 includes a through-hole 12 adapted to receive and / or interact with a positioning element (not shown) configured to fix the position of the fastening element 6 relative to the fuel cell stack. For example, the positioning element may be a screw.

[0032] To secure the base 10 to the strip element 2, the base 10 includes a plurality of weld protrusions 16 on the side of the base 10 facing the strip element 2. The clamping band 1 of the illustrated embodiment has four weld protrusions. Alternatively, the clamping band 1 may have two, three, five, six, or even more weld protrusions. The weld protrusions 16 may have an arcuate shape and be arranged separately from each other around the circumference of the base 10. Preferably, the shape of the weld protrusions is similar to the circumferential shape of the base. Preferably, each weld protrusion 16 may have the same length. However, the lengths of the weld protrusions 16 may also differ from each other.

[0033] In the illustrated embodiment, the weld protrusions 16 are equidistant from each other. However, more weld protrusions may be provided in areas subjected to higher loads than in areas subjected to lower loads. For the illustrated clamping band 1, the load is typically applied between the first and second ends along the longitudinal direction of the band element 2. Figure 2 As can be seen, three of the four weld protrusions 16, namely 16-1, 16-2, and 16-3, are arranged such that they are directly on the line of action of the load acting in the longitudinal direction of the strip element 2 (see arrow).

[0034] Preferably, the fastening element 6 is automatically welded to the strip element 2. Therefore, in order to ensure that the weld protrusions 16 are arranged such that they are directly on the line of action of the load acting in the longitudinal direction of the strip element 2, it is necessary to provide a mark 14, which is configured to indicate the position and / or orientation of the fastening element 6 relative to the strip element 2, and thereby indicate the position and / or orientation of the weld protrusions 16 relative to the strip element 2.

[0035] In the illustrated embodiment, the mark 14 is a flat area located on the curved surface of the cylindrical bolt portion 8. However, the mark can be any other geometric and / or optical feature that can be detected visually and / or by means of a camera device. For example, the mark can be one or more coated or engraved lines, one or more dots or one or more symbols, and / or grooves, notches and / or protrusions. Alternatively or additionally, the mark 14 can be arranged on the base 10.

[0036] In summary, the described clamping band 1 offers improved service life and stability. More specifically, by using at least one mark 14 to indicate the position and / or orientation of the fastening element 6 and / or the weld protrusion 16, wherein the fastening element 6 is connected to the strip element 2 of the clamping band 1 via the weld protrusion 16, it can be ensured that at least one weld protrusion 16 is positioned in a predetermined location even when welding is performed automatically. Therefore, the consistency of the alignment of the weld protrusion 16 with respect to the strip element 2 (particularly with respect to the longitudinal direction of the strip element 2) can be improved.

[0037] Figure Labels

[0038] 1. Clamping strap

[0039] 2. Strip element

[0040] 4 First end

[0041] 6 Fastening components

[0042] 8 Bolt section

[0043] 10 Base

[0044] 12 Through Holes

[0045] 14 Marks

[0046] 16 Welding protrusions

Claims

1. A clamping band (1) for maintaining compression of a fuel cell stack assembly, particularly a clamping band (1) for maintaining compression of a fuel cell stack assembly, comprising at least an elongated strip element (2) having a first end (4) and a second end, and at least one fastening element (6) for securing the strip element (4) to the fuel cell stack assembly, wherein the fastening element is a separate element permanently attached to the strip element (2), characterized in that, The fastening element (6) has an alignment feature (14) for defining the attachment orientation of the fastening element (6) relative to the strip element (2), such that the fastening element (6) is attached to the strip element (2) in a predetermined position and / or in a predetermined orientation.

2. The clamping band (1) according to claim 1, wherein the alignment feature is a mark (14) indicating the position and / or orientation of the fastening element (6) relative to the band element (2).

3. The clamping band (1) according to claim 1 or 2, wherein the at least one mark (14) is a geometric and / or optical feature of at least a portion of the fastening element (6).

4. The clamping band (1) according to any one of the preceding claims, wherein the at least one fastening element (6) further comprises a base (10) and a bolt portion (8), wherein the base (10) is configured to be attached to the band element (2) and the bolt portion is configured to be attached to the fuel cell assembly, wherein at least one mark (14) is disposed on the bolt portion (8) and / or the base (10).

5. The clamping band (1) according to claim 4, wherein at least the band element (2) and the base (10) are made of metal, and wherein the base (10) is welded to the band element (2).

6. The clamping band (1) according to claim 5, wherein the base (10) includes at least one welding protrusion (16) for welding the base (10) to the strip element (2), wherein the at least one mark (14) is configured to indicate the position of the at least one welding protrusion (16).

7. The clamping band (1) according to claim 6, wherein the at least one welded protrusion (16) is arranged such that it is at least partially aligned with the load direction of the clamping band (1).

8. The clamping band (1) according to claim 6 or 7, wherein the base (10) comprises a plurality of discrete weld protrusions (16).

9. The clamping band according to claim 8, wherein the plurality of weld protrusions are arranged such that there are more weld protrusions in the region subjected to higher loads than in the region subjected to lower loads.

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