SPACER FABRIC AND USE THEREOF

Abstract

A spacer fabric has two transversely spaced cloth layers. First spacer yarns bridge and transversely connect the cloth layers and are each formed by a core yarn and a helical wrapping made of metal or having a metallic layer. Second spacer yarns also bridge and transversely connect the cloth layers but are of different construction from the first yarns.

Claims

1. A spacer fabric comprising: two transversely spaced cloth layers; and first spacer yarns that bridge and transversely connect the cloth layers and that are each formed by a core yarn and a helical wrapping made of metal or having a metallic layer.

2. The spacer fabric defined in claim 1, wherein the wrapping is formed of metallic strip having a width and a thickness, a ratio of the width to the thickness bing at least 5:1.

3. The spacer fabric defined in claim 2, wherein the strip is flattened wire.

4. The spacer fabric defined in claim 3, wherein the wire is of copper or has a coating of copper.

5. The spacer fabric defined in claim 2, wherein the strip is wound helically around the core yarn and forms a plurality of spaced turns between which the yarn is exposed.

6. The spacer fabric defined in claim 5, wherein the strip covers 30% to 95% of the core yarn.

7. The spacer fabric defined in claim 1, further comprising: second monofilament spacer yarns that also bridge and transversely connect the cloth layers but that are of different construction from the first yarns. wherein the second spacer yarns are monofilaments.

8. The spacer fabric defined in claim 1, wherein the core yarn is a multifilament yarn.

9. The spacer fabric defined in claim 1, wherein the cloth layers and first and second spacer yarns are knitted.

10. The spacer fabric defined in claim 1, wherein a total thickness of the spacer fabric is between 1 mm and 20 mm.

11. The spacer fabric defined in claim 1, wherein the core yarn has a fineness between 50 dtex and 150 dtex.

12. The spacer fabric defined in claim 1, wherein the wrapping has a cross-sectional area of between 200 m.sup.2 and 10,000 m.sup.2.

13. The spacer fabric defined in claim 1, wherein the first spacer yarns have a cross-sectional shape that is not circular.

14. Use of the spacer fabric of claim 1 as a heat conduction layer.

15. The use defined in claim 14, wherein the spacer fabric is connected to an electrical component.

16. The use defined in claim 14, wherein the spacer fabric is in a gap between a housing wall and the electrical component.

17. A method comprising the steps of: forming first yarns of a multifilament nonconductive core yarn wrapped helically by a conductive and flexible metal strip; providing second monofilamentary yarns; and knitting together the first and second yarns into a spacer fabric formed of two transversely spaced cloth layers largely formed of the second yarns and bridged by first spacer yarns formed by the first yarns and by second spacer yarns formed by the second yarns.

Description

BRIEF DESCRIPTION OF THE DRAWING

[0036] The above and other objects, features, and advantages will become more readily apparent from the following description, reference being made to the accompanying drawing in which:

[0037] FIG. 1 is a perspective view of a piece of a knitted spacer fabric or fabric according to the invention;

[0038] FIG. 2 is a larger-scale view of a detail of the fabric of FIG. 1;

[0039] FIG. 3 is a view of a short piece of a spacer yarn of the knitted spacer fabric according to FIG. 1 that is made of a yarn and a wrapping;

[0040] FIGS. 4a to 4c shows method steps for forming the spacer yarn of this invention; and

[0041] FIG. 5 is a schematic view of a rechargeable battery module in a housing.

SPECIFIC DESCRIPTION OF THE INVENTION

[0042] FIG. 1 shows a spacer fabric in the form of a knitted spacer fabric with two cloth layers 1 and first and second spacer yarns 2a and 2b that extend transversely between the planes of and connect the layers 1. FIG. 1 and the detail view of FIG. 2 show that the spacer yarns 2a and 2b are configured differently. The first spacer yarns 2a each have a core 3 formed by a multifilament yarn and a helical wrapping 4 around the core 3. The wrapping 4 is made of metal or has at least one metallic layer.

[0043] It can already be seen from the detailed view of FIG. 2 that, if desired, good electrical conduction can also be achieved by the metallic wrapping 4 transversely, in the direction of thickness, the other spacer yarns 2b are formed of polymeric monofilaments.

[0044] The different spacer yarns 2a and 2b extend similarly between the two cloth layers 1 and also are of a similar thickness. While the metal-wrapped first spacer yarns 2a ensure good conduction of heat and electricity, the second spacer yarns 2b can provide the compression hardness and elastic recovery that are typical of a spacer fabric and particularly a knitted spacer fabric.

[0045] The exact configuration of the first spacer yarns 2a provided with the sheath 4 can be seen from the sectional view of FIG. 3. In the illustrated embodiment, the core 3 is a multifilament yarn with for example a fineness of 76 dtex. Polyethylene terephthalate is particularly suitable as the material, but other typical materials such as various polyolefins, polyamide, and the like can also be employed.

[0046] It can be seen from FIG. 3 that the wrapping 4 has a strip-shaped configuration with a width b and a thickness d, the ratio of the width b to the thickness d being at least 5:1. In the illustrated embodiment, the wrapping 4 is made of tinned copper, it being possible for an initially circular-section tinned copper wire to be flattened in order to form the strip-shaped configuration. Such a method step is shown by way of example in FIG. 4a.

[0047] It is also apparent from FIGS. 2 and 3 that there is a gap between the successive turns of the wrapping 4, 30% and 95% of the core being covered.

[0048] The helical wrapping 4 also has the effect that the effective length for heat conduction or electrical conduction of the wrapping 4 is greater than the length of the core. In the unwound state, the wrappings 4 typically have a length that is 2 to 2.5 times greater than that of the respective core yarns 3. Despite this increased path length, very good conduction of heat is observed overall.

[0049] For example, the wrapping can have a cross-sectional area of between 200 m.sup.2 and 10,000 m.sup.2, particularly between 600 m.sup.2 and 4000 m.sup.2. The multifilament yarn that is here provided as the core 3 can have 24 or 36 filaments, for example.

[0050] FIG. 4b indicates how the core 3 of multifilament yarn can be provided with the wrapping 4. Finally, FIG. 4c shows that the first spacer yarns 2a can also be flattened to some extent before the knitting process to stabilize their cross-sectional shape and wrapping.

[0051] The spacer fabric according to the invention is provided in an especially advantageous manner as a heat conduction layer, it being also optionally possible for ventilation to take place through it. In this context, the highly schematic representation of FIG. 5 shows the arrangement of a rechargeable battery module 5 in a housing 6, with the spacer fabric forming an intermediate layer 7 between the outer surface of the module Sand the inner surface of the housing 6. In particular, this spacer fabric as an intermediate layer 7 can be used to compensate for a remaining gap between the rechargeable battery module 5 and the housing 6. It should also be noted that the actual gap to be bridged can vary greatly due to manufacturing-related variations. Particularly in this context, the invention offers the advantage that the spacer fabric can be compressed when used as a heat conduction layer and also resets elastically to a certain extent. Such compensation is not possible with a thermally conductive paste or other compact media.