Patent Application
20250172632
The disclosure relates to an electrical contacting element designed as a sheet metal clamp. Furthermore, the disclosure relates to a measuring assembly for measuring an electrical voltage in a fuel cell system, which comprises a stack of electrochemical cells, namely fuel cells, with a plurality of bipolar plates.
EP 1 900 052 B1 discloses a bipolar plate which is composed of two half-sheets, namely what is termed a half cathodic bipolar plate and a half anodic bipolar plate. In addition to numerous other three-dimensional structures, the half-sheets form hollow receptacles into which electrical connection elements can be inserted for measuring purposes.
A further plug connector for measuring a cell voltage of a fuel cell is described in DE 10 2018 110 870 A1. In this case, a plug connector is mounted in a diagonal direction relative to the external shape of the fuel cells.
Various variants of electrical connection elements formed from sheet metal are described, for example, in the documents WO 2018/193347 A1, DE 20 2018 006 251 U1 and DE 1 002 435 B.
The documents DE 10 2010 010 331 A1 and DE 10 2009 053 206 B4 disclose electrical contacting elements which are designed for attachment to planar elements.
The disclosure is based on the object of specifying methods for contacting electrically conductive planar components, in particular in the form of bipolar plates of electrochemical cells, which are more advanced than the prior art, wherein a high level of process reliability should be ensured even under series production conditions and application possibilities are sought, among other things, for densely stacked plates, as can be found in fuel cell stacks.
According to the disclosure, this object is achieved by an electrical contacting element having the features described herein. The contacting element can be used in a measuring assembly designed according to embodiments disclosed herein for voltage measurement in a fuel cell system.
The contacting element is a sheet metal clip with a folded basic shape. This means that the contacting element has at least an approximately U-shape in cross-section. Two planar clamp parts arranged essentially parallel to each other, which represent the two U-legs in cross-section, are referred to without restriction of generality as the lower clamp part and upper clamp part. When the clamp parts mentioned are viewed from above, they are integrally connected to each other by a linear connecting region. If the lower clamp part and the upper clamp part have a non-square basic shape, the connecting region can be located in particular on one long side of the clamp parts lying on top of each other.
Due to the spring-elastic properties of the sheet metal clamp, the planar clamp parts are spring-loaded against each other. The electrical contacting element is suitable for both automated and manual assembly processes. In both cases, the incomplete overlap of the two planar clamp parts makes it easier to bend the clamp parts during assembly. If the sheet metal clamp is gripped at the linear connecting region by hand or by a manipulator, which can be part of an assembly robot, the bending can be easily achieved by a slight rotary movement with which the lower clamp part is deflected slightly downwards and the upper clamp part slightly upwards. The direction information refers to a conceivable horizontal arrangement of the sheet metal clamp and does not imply any statement about the actual installation situation.
The two planar, plate-like clamp parts can have identical outer contours, whereby the lower clamp part emerges from the upper clamp part by mirroring on a mirror axis running orthogonal to the linear connecting region. The partial covering of one clamp part by the other clamp part is designed in particular in such a way that when one of the clamp parts is viewed from above, less than a quarter of the other clamp part is visible.
When the lower clamp part or the upper clamp part is viewed from above, the sheet metal clamp describes a modified rectangular shape according to various designs that are favorable for assembly. In this case, the side lines of the sheet metal clamp, which are opposite the linear connection region, can each be composed of several adjacent sections, wherein one of these sections is aligned to be at least approximately parallel to the linear connection region, and an adjoining section is inclined relative to the linear connection region. In both the lower clamp part and upper clamp part, the angled section can be longer than the first section.
Overall, the planar clamp parts can thus form a V-shaped incision on the side of the sheet metal clamp which is opposite the linear connecting region. Similarly, in case of curved contours of the clamp parts, a rounded recess can be formed on a side line of both clamp parts.
What is termed the linear connection region can be designed in such a way that a distance is created between the two planar clamp parts, wherein the distance is to be measured in the normal direction of the planar clamp parts, and typically corresponds approximately to the wall thickness of a plate, in particular a bipolar plate, to which the contacting element is to be attached.
In cross-section, the connecting region, which appears linear when one of the planar clamp parts is viewed from above, corresponds to a U-base to which the two U-legs, i.e., planar clamp parts, are connected. When assembled, the two planar clamp parts of the contacting element are spaced apart from each other by the electrical contacting plate located between these clamp parts.
As long as the contacting element is not yet attached to the plate, in particular the bipolar plate, there is a considerable preloading force between the clamp parts, which leads to the clamp parts contacting each other at the side lines thereof opposite the connecting region, but not in the vicinity of the linear connecting region. The preloading force can be set such that in the bending region, i.e., in the linear connecting region, the tensile strength of the material, i.e., heat-treated sheet metal, in particular steel sheet, is utilized between 50% and 99%. The sheet metal clamp, for example, has a material thickness of 50 μm to 200 μm. This makes the sheet metal clamp suitable for use with fuel cell stacks that have a cell spacing of approximately 1.0 mm to 1.2 mm.
The measuring assembly designed according to claim 9 for voltage measurement in a fuel cell system comprises at least one bipolar plate and a contacting element designed according to claim 1 which is attached to this plate. The wall thickness of the contacting element, for example, is in the range of 25% to 200% of the wall thickness of the bipolar plate. The bipolar plate can be constructed in a conventional manner from two half-sheets. Due to the low wall thickness of the contacting element, it requires practically no additional installation space within a stack of fuel cells.
According to an expedient further development, at least one planar clamp part, i.e., the lower clamp part and/or the upper clamp part, has at least one tongue acting in the sense of a barb, which is formed directly onto the clamp part in question. The tongues can be located in the middle region of the planar clamp parts, i.e., be spaced from the edges thereof.
The connecting region, which appears linear when the planar clamp parts are viewed from above, can be interrupted once or several times, i.e., it can be formed from individual connecting sections spaced apart from one another. In this case, a section located between two connecting sections can have a tab intended for connection to a cable, which is formed either on the lower clamp part or on the upper clamp part. In the other part of the clamp, there can be a recess at the corresponding point, which is created by punching out the tab. With regard to the spring properties of the sheet metal clamp, this recess is of no practical relevance.
Several exemplary embodiments of the disclosure are explained in more detail below by means of drawings. In the drawings:
Unless otherwise stated, the following explanations relate to all the exemplary embodiments. Parts that correspond to each other or have basically the same effect are denoted with the same reference symbols in all the figures.
A bipolar plate, designated overall by the reference symbol 2, is intended for use in a fuel cell stack and has various ports 3, 4, 5 for the introduction of media. A distribution field of the bipolar plate 2 is designated with 6, an active field with 7. Ports for media output are not shown. With respect to the basic function of a bipolar plate 2, reference is made to the prior art cited at the outset.
A contacting element 1 attached to the bipolar plate 2 enables the measurement of the electrical voltage applied to the bipolar plate 2. The contacting element 1 has the basic shape of a folded sheet metal clamp, with a planar lower clamp part designated 8 and a likewise planar upper clamp part designated 9. The terms “lower part” and “upper part” are used without restriction of generality. In fact, in many applications, the bipolar plate 2 is located in a vertical orientation in a fuel cell stack. The bipolar plate 2 has an elongated rectangular shape, wherein the contacting element 1 is, for example, plugged into one of the shorter sides of the bipolar plate 2, as sketched in
The two planar clamp parts 8, 9 of the contacting element 1 are connected to one another by a comparatively narrow connecting region 10 which appears linear when viewed from above (
Each clamp part 8, 9 can be represented as a combination of a rectangle and a trapezoid, whereby the rectangle is limited, among other things, by the longer narrow side 16 and the section 14 and the trapezoid is limited, among other things, by the shorter narrow side 17 and the section 15. The two rectangular-trapezoidal combinations, which are described by the clamp parts 8, 9, are arranged in mirror image to each other, with a mirror axis placed centrally between the two narrow sides 16, 17.
When the upper clamp part 9 is viewed from above, as shown in
To prevent the contacting element 1 from being accidentally pulled off the bipolar plate 2, there is a tongue 18 in one of the planar clamp parts 8, 9, in the exemplary embodiments always in what is termed the upper clamp part 9, which acts in the manner of a barb. The tongue 18 can be deflected within a recess designated 19, which is located in the upper clamp part 9.
The connecting region 10, which is linear in shape in all embodiments, is formed from connecting sections 20, 21, 22 which are separated from one another, whereby intermediate regions in which the clamp parts 8, 9 are not connected to one another are designated by 23, 24. The missing direct connection between the clamp parts 8, 9 in the intermediate regions 23, 24 can be used to form a tab 25 which is punched out of one of the clamp parts 8, 9 and protrudes from the other clamp part 9, 8 in the usable, formed state of the contacting element 1, as can be seen in
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2022 101 247.6 | Jan 2022 | DE | national |
This application is the U.S. National Phase of PCT Appln. No. PCT/DE2022/100832 filed Nov. 10, 2022, which claims priority to German Application No. DE 10 2022 101 247.6 filed Jan. 20, 2022, the entire disclosures of which are incorporated by reference herein.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/DE2022/100832 | 11/10/2022 | WO |
