DE102017203096A1 - Heat conduction and battery arrangement - Google Patents

Abstract

The invention relates to a Wärmeleitanordnung (1) and a battery assembly. The heat conducting arrangement (1) has a heat conducting core (2) and at least one metallic heat conducting layer (3) adjacent to this heat conducting core (2). In addition, the heat conducting core (2) consists of a metal fiber composite (4), which is completely enclosed by the at least one heat conducting layer (3). Moreover, the battery assembly comprises a battery and a cooling device, wherein the battery has at least one battery cell and a housing, on which the cooling device is arranged. Between the battery cell and the housing and / or between the housing of the battery and the cooling device further at least one heat conducting arrangement (1) is arranged.

Description

The invention relates to a Wärmeleitanordnung with a Wärmeleitkern and at least one adjacent to this Wärmeleitkern metallic heat conduction. Furthermore, the invention relates to a battery assembly with a battery and a cooling device, wherein the battery has at least one battery cell and a housing, on which the cooling device is arranged.

In the course of increasing electric mobility, there is a steadily increasing demand for powerful energy storage devices, especially in motor vehicle construction. Such energy storage exist in the form of accumulators, via which the energy required to drive electric motors is provided. Due to the power required to drive a motor vehicle, which has to be borne by a driving electric motor, the current flow through the stator windings of such electric motors is also at a level at which a significant heating of the electric motors is produced. However, this current flow not only causes a heating of the electric motor. Also, accumulators, which are taken from the necessary currents to drive the electric motors, heat up due to this current flow. In order to avoid thermal damage to the accumulators, cooling systems can be used, which are arranged on the housing of the accumulators.

Since the accumulator housing naturally have high surface tolerances due to their manufacturing process, arises between the accumulator housing and the cooling system, a contact area, which is significantly less than the actually possible contact area between the accumulator housing and the cooling system. This is to be regarded as disadvantageous in two respects, since on the one hand the effective contact area for heat conduction decreases and on the other hand in non-contacting areas, d. H. exist in the resulting cavities between accumulator housing and cooling system, heat-insulating air pockets. Such cavities can also be structurally conditioned. As a result, a significant reduction in the heat flow between the accumulator and the cooling system is the result. Similar statements can also be made to the internal structure of a battery. In particular, high manufacturing tolerances are to be expected between the cell modules of the accumulator and the accumulator housing. For this reason, a distance is usually already structurally provided, as a balance is needed in any case.

To increase the heat conduction between the cell module and the accumulator housing and the accumulator housing and the cooling system, it is possible to introduce heat-conducting materials, for example in the form of heat-conducting pads, between the contact surfaces.

The materials are usually based on metal oxides embedded in elastomers and have on average only ten percent of the thermal conductivity of the embedded metal oxide. In turn, the metal oxides themselves have a maximum of more than twenty percent of the underlying metal oxide metal. With increasing material thickness, the already low coefficient of thermal conductivity also decreases beyond the measures.

The US 2009/0117345 A1 discloses for this purpose a Wärmeleitmaterialverbund, which consists of a thermally conductive material based on elastomer or a phase change material and at least one further separating layer of a metal or a polymer. Furthermore, for the application or introduction of the material between a heat-generating component and a component dissipating the heat, further layers, in particular release papers or transfer films, may belong to the heat-conducting material composite. These release papers or transfer films are siliconized in this case, wherein the silicone applied again serves as a release layer. However, during or after application of the heat-conducting composite, the release papers or transfer sheets are removed. The layer thicknesses of the individual layers are in the range of a few micrometers, in some cases they are only in the range of nanometers.

With such pronounced material composites, only very small manufacturing tolerances can thus be compensated. Tolerances down to the range of a few millimeters can not be compensated disadvantageously.

Against this background, the invention has for its object to perform a Wärmeleitanordnung of the aforementioned type such that a distance compensation for distances that are significantly higher than recorded in the prior art, is possible. Furthermore, the invention has for its object to provide a battery assembly of the type mentioned with improved cooling available.

The first object is achieved with a Wärmeleitanordnung according to the features of claim 1. The dependent claims relate to particularly expedient developments of the invention.

According to the invention, therefore, a heat conduction arrangement with a heat conducting core and at least one metallic heat conducting layer adjacent to this heat conducting core is provided. This consists the Wärmeleitkern of a metal fiber composite, which is completely enclosed by the at least one Wärmeleitlage, wherein thus the metal fiber composite is quasi embedded in the at least one Wärmeleitlage.

Such a trained Wärmleitanordnung combines several advantages in itself. On the one hand, it is possible that both small distances to be bridged between a heat source and a heat sink in the range of 0.1 millimeters to 0.5 millimeters and larger distances to be bridged in the range of 0.5 millimeters to 5 millimeters, and in particular up to 2 millimeters, with high thermal conductivity of the Wärmeleitanordnung can be connected. This is due to the high flexibility, d. H. the pronounced elastic properties in the form of a high elastic modulus and a high yield strength of the metal fiber composite in combination with its high compressibility. The compressibility is largely due to the present between the metal fibers of the metal fiber composite, air-filled cavities whose volume is minimized in a compression of the metal fiber composite. Furthermore, the cladding of the metal fiber composite with the heat conducting layer causes a large contact area to the heat sink and the heat source. At the same time, the heat conduction layer provides protection against metal fibers possibly emerging from the metal fiber composite, which reduces the risk of a defect. Despite the air-filled cavities between the metal fibers of the metal fiber composite can be achieved in the range of 10 watts per Kelvin per meter to 20 watts per Kelvin per meter or even up to 25 watts per Kelvin due to the use of metals with correspondingly high heat transfer coefficients Wärmeleitkoeffizienten a total Wärmeleitkoeffizient per meter. This Gesamttwärmeleitkoeffizient thus would be at least twice as high as a thermal conductivity of Wärmeleitmaterialien based on embedded in elastomers metal oxide particles. In addition, only a slight fluctuation of the overall thermal conductivity of the Wärmeleitanordnung would be expected at a compression of this in the range of one watt per Kelvin per meter to two watts per Kelvin per meter. This should also be the case if a different thickness of the heat conduction arrangement over its areal extent due to the adaptation to a surface contour of the heat source and heat sink adjusts.

With regard to the Wärmleitlagen is conceivable that only a heat conduction is provided, which at least partially, for example, in the edge regions of the metal fiber composite, the metal fiber composite facing or facing overlapped. However, it could also be provided, among other things, two heat conduction, which include the metal fiber composite on all sides and which overlap at least in sections in its edge region. This overlapping edge region could also be used to connect the heat conducting layers to each other, for example by material bonding. A hereby possible supernatant of the heat conduction over the metal fiber composite may differ depending on the requirement. An unconnected part of the edge region could serve to equalize the pressure during compression of the heat conduction assembly.

Furthermore, due to the reduced production costs and the materials used, the heat conduction arrangement according to the invention compared to heat conducting materials, which are based on metal oxide particles embedded in elastomers, given a significant cost savings.

In a particularly advantageous embodiment of the invention, the metal fiber composite in the form of a metal nonwoven with disordered metal fibers with the same and / or different fiber length is pronounced. By a disordered expression of the metal fibers in the formed as a metal fleece metal fiber composite z. B. isotropic mechanical properties, such as the elasticity behavior and / or the rigidity, reach in the spatial directions of the metal fiber composite.

A further advantageous development of the invention is also characterized in that the metal fiber composite in the form of a metal fabric, knitted fabric or knitted fabric is pronounced with ordered fibers of the same and / or different fiber length. By an orderly expression of the metal fibers in the formed as a metal fleece metal fiber composite could, contrary to an orderly expression, z. B. anisotropic mechanical properties, such as the elasticity and / or stiffness, reach in the spatial directions of the metal fiber composite.

In both cases, ie the orderly or disorderly expression of the metal fibers in the metal fiber composite designed as metal fleece, the mechanical properties, such as elasticity and / or stiffness, the geometric properties of the metal fibers, such as their length and cross section, as well as their number in metal fleece and associated therewith the metal fiber density and the material of which the metal fibers of the metal nonwoven consist. Steels, aluminum-coated steels, but also copper and aluminum, or even mixtures thereof, could be considered as the material.

Moreover, in cases of orderly or disorderly expression, the Metal fibers in the metal fiber composite conceivable to convert them into a desired geometric shape, which would result, for example, by the positioning of the Wärmeleitanordnung. This could be done inter alia by a pressing process of the metal fiber composite. Depending on the desired mechanical properties, it would be advantageous to choose an ordered or unordered characteristic of the metal fibers in order to achieve direction-dependent or direction-independent properties of the metal fiber composite and thus of the heat conduction arrangement.

An extremely profitable embodiment of the invention is also due to the fact that the metallic heat conduction layer is formed in the form of a metal foil. The metal foil could have a thickness in the range of 0.1 millimeters to 0.5 millimeters and in particular a thickness of 0.2 millimeters. As materials for this metal foil would z. As aluminum and copper, but also steels and / or aluminum-coated steels in question. By using the metal foil as the heat-conducting layer, it is possible to profitably achieve an excellent adaptability to the cavity to be filled out by the heat-conducting arrangement between the heat source and the heat sink and at the same time having a high contact surface. Moreover, due to its closed-surface structure, the metal foil is particularly well suited to enclose the metal fiber composite and to prevent fibers from escaping therefrom.

In addition, if the metallic heat conduction layer formed as a metal foil has a perforation and / or an embossing, then this is to be described as having an advantage that different strength properties such as the level of tear strength and rigidity can be determined in the metal foil due to and depending on the embossing introduced are. On the other hand, it would be possible on the basis of the perforation of the metal foil that the air located in the cavities between the metal fibers of the metal fiber composite can escape during compression of the Wärmeleitanordnung from the Wärmeleitanordnung. Thus, a complete connection of the formed as a metal foil Wärmeleitlage in its edge region would be conceivable. The perforation should be in the form of holes which are formed in the direction of the thickness of the metal foil and have a diameter of less than one millimeter, in particular less than 0.1 millimeter. The production of the holes could be done by micro-needling, etching or laser processing.

Furthermore, an embodiment of the invention may be regarded as promising if the metallic heat conduction layer is designed in the form of a metal mesh whose mesh size is less than a cross-sectional dimension and / or a minimum length of the intact and / or defective metal fibers present in the metal fiber composite. By using a metal mesh, during the compression of the heat conduction arrangement, a similar air flow between the cavities of the metal fiber composite and the surroundings of the heat conduction arrangement would be made possible. In this case, a perforation of the metal mesh would not be necessary due to its mesh structure. However, the mesh size of the metal mesh should be so small that in turn can not escape metal fibers of the metal fiber composite from the Wärmeleitanordnung. This applies both for themselves in the metal fiber composite fibers and for metal fibers, which due to overloading of the metal fiber composite, z. B. by breakage, have leaked. For this reason, a mesh size should be provided which is less than 1 millimeter, in particular less than 0.1 millimeter.

In addition, it proves to be very practical if the metallic heat conducting layer has on its side facing the metal fiber composite a bonding agent layer via which the heat conducting layer can be adhesively bonded to the metal fiber composite. This would advantageously lead to a further increase in the overall thermal conductivity of the Wärmeleitanordnung, as a loose contact and thus also a change in the contact points between the heat conduction and metal fiber composite would be prevented.

If, in addition, the primer layer consists of a hard or weichlötbaren metal and / or a metal alloy or a Wärmeleitkleber, then there are opportunities to generate a material connection between heat conduction and metal fiber composite, which only a thin layer thickness of the primer layer range from 50 microns to 100 microns provide. As a result, a cohesive contact between metal fiber composite and heat conduction and a high heat transfer coefficient can be guaranteed at the same time. The adhesion promoter layer could for this purpose consist of tin or a tin alloy with constituents of copper and / or silver. In one embodiment, the adhesive layer as a thermal adhesive this could be based on epoxy or silicone-based, wherein in the epoxy resin or silicone ceramic or metallic fillers are introduced.

The heat treatment necessary when using a hard or weichlötbaren metal as a primer layer for cohesive connection of thermal conductivity and metal fiber composite could be done during or after placement of the heat conduction around the metal fiber composite.

A particularly promising embodiment of the heat conduction arrangement according to the invention is also given by the fact that the heat conduction arrangement has an electrical insulation layer and / or an electrical insulation layer on the side of the heat conduction layer facing away from the metal fiber composite. By means of the insulating layer and / or the insulating layer, in the case of electrically critical applications in which no contact of the heat source and heat sink with an electrically conductive heat conducting arrangement is desired, a line of electrical current could be prevented through the heat conducting arrangement. The electrical insulation layer could consist of an electrically non-conductive foil, which encloses the Wärmeleitanordnung. On the one hand, the film could be in loose contact with the heat-conducting layer or, on the other hand, rolled or laminated onto it. In the case of the insulating layer, application of this by means of known coating methods such as dip or spray coating, vapor deposition or even cathode sputtering onto the heat conduction layer is conceivable. It should be noted that a possible perforation of the heat conduction in the insulation layer and / or insulation layer is continued.

The second object is also achieved with a battery assembly according to the features of claim 10.

Thus, according to the invention, a battery arrangement with a battery, which has at least one battery cell and a housing, and a cooling device arranged on the housing of the battery is being considered. In this case, moreover, at least one heat-conducting arrangement described above is arranged between the battery cell and the housing and / or between the housing of the battery and the cooling device. In particular, the battery should be designed as a rechargeable accumulator. Due to the arrangement of the heat transfer arrangement or several heat transfer arrangements between the at least one battery cell and the housing or the housing and the cooling device would in relation to a version without Wärmeleitanordnung and in relation to the arrangement of Wärmeleitmaterialien between battery cell and housing and / or housing and the cooling device, which are based on metal oxide particles embedded in elastomers, set an increased heat flow between the battery cell and the housing and / or between the housing and the cooling device, whereby an increase in temperature of the battery during operation would be lower. Thus, z. B. increase the life of the battery and / or realize a higher current drain.

• 1 einen prinzipiellen Aufbau einer erfindungsgemäßen Wärmeleitanordnung;
• 2a, 2b, 2c Querschnitte von erfindungsgemäßen Wärmeleitanordnungen;
• 3 eine Wärmeleitanordnung mit Metallnetz;
• 4 eine erfindungsgemäße Batterieanordnung.

The invention allows numerous embodiments. To further clarify its basic principle, some of them are shown in the drawing and will be described below. The drawing shows in

• 1 a basic structure of a Wärmeleitanordnung invention;
• 2a . 2 B . 2c Cross sections of Wärmeleitanordnungen invention;
• 3 a Wärmeleitanordnung with metal network;
• 4 a battery arrangement according to the invention.

1 shows the basic structure of a Wärmeleitanordnung invention 1 in an exploded view. The heat conduction arrangement 1 shows the heat conducting core 2 , which in this case from the metal fiber composite 4 consists. In addition, the Wärmeleitanordnung 1 the at the Wärmeleitkern 2 adjacent metallic heat conduction 3 on which the metal fiber composite 4 completely encloses. It should be noted in addition that the metallic heat conduction 3 in the form of the metal foil 8th is formed, which with the perforation 9 is provided. The as metal foil 8th formed metallic Wärmeleitlage 3 also shows on her the metal fiber composite 4 facing side of the primer layer 10 , about which the thermal conductivity 3 with the metal fiber composite 4 is connected cohesively. Also in the adhesive layer 10 is the perforation 9 shown as this continues in the primer layer 10.

2a . 2 B and 2c illustrate cross sections of heat conduction arrangements according to the invention 1 , where the in 2a as in 2c shown representations Wärmeleitanordnungen 1 include, their metal fiber composite 4 in the form of metal fleece 7 with disordered metal fibers 5 different fiber length is pronounced. On the other hand, the in 2 B illustrated Wärmeleitanordnung 1 over a metal fiber composite 4 , which is in the form of metal mesh 6 with ordered metal fibers 5 same and different fiber length is pronounced. The as metal fleece 7 or as metal mesh 6 trained metal fiber composite 4 is in turn of the metal foil 8th trained thermal conductivity 3 or the heat conduction 3 enclosed. This again has on its the metal fiber composite 4 side facing the adhesive layer 10 on, over which the heat conduction 3 with the metal fiber composite 4 is connected cohesively. In the 2a . 2 B and 2c is also a different degree of thermal conductivity 3 shown. The 2a and 2 B show Wärmeleitanordnungen 1 with two cohesively on the adhesive layer 10 connected heat conduction 3 , The heat conduction 3 close the metal fiber composite 4 on all sides, being in their peripheral area 11 , the Metal fiber composite 4 turned away, overlapping. The supernatant 12 the heat conduction 3 over the metal fiber composite 4 differs in the 2a and 2 B to the effect that the supernatant 12 the in 2a shown heat conduction 3 greater than the supernatant 12 the in 2 B shown heat conduction 3 , In the 2c illustrated Wärmeleitanordnung 1 on the other hand only shows a thermal conductivity 3 , This heat conduction 3 overlaps in contrast to Figures 2a and 2b, the metal fiber composite 4 facing, in the edge area 11 of the metal fiber composite 4 ,

In 3 is a Wärmeleitanordnung 1 represented, whose metallic heat conduction 3 in the form of a metal net 13 are formed. The metal nets 13 enclose the metal fiber composite 4 , which in this case in the form of a metal fleece 7 with disordered metal fibers 5 is trained. Furthermore, the metal nets 13 in her the metal fiber composite 4 remote edge area 11 connected with each other.

4 shows a schematic representation of a battery assembly according to the invention 20 The battery arrangement 20 points the battery 21 and the cooling device 24 on. The battery 21 itself also has four battery cells 22 and the case 23 at which the cooling device 24 is arranged. Moreover, there are between the battery cells 22 and between the cooling device 24 facing battery cell 22 and the housing 23 and between the case 23 the battery 21 and the cooling device 24 one each Wärmeleitanordnung 1 arranged.

LIST OF REFERENCE NUMBERS

1

Wärmeleitanordnung

2

Heat-conductive

3

Wärmeleitlage

4

Metal fiber composite

5

metal fibers

6

Metal fabric, knitted or knitted fabrics

7

metal fleece

8th

metal foil

9

perforation

10

Bonding layer

11

border area

12

Got over

13

metal mesh

20

battery assembly

21

battery

22

battery cell

23

casing

24

cooler

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• US 2009/0117345 A1 [0006]

Claims (10)

Heat conducting arrangement (1) with a heat conducting core (2) and at least one metallic heat conducting layer (3) adjoining this heat conducting core (2), characterized in that the heat conducting core (2) consists of a metal fiber composite (4), which by the at least one heat conducting layer ( 3) is completely enclosed. Wärmeleitanordnung (1) after Claim 1 , characterized in that the metal fiber composite (4) in the form of a metal fleece (7) with disordered metal fibers (5) is pronounced with the same and / or different fiber length. Wärmeleitanordnung (1) according to claims 1 or 2, characterized in that the metal fiber composite (4) in the form of a metal fabric, knitted fabric or knitted fabric (6) with ordered metal fibers (5) of the same and / or different fiber length is pronounced. Wärmeleitanordnung (1) according to at least one of the preceding claims, characterized in that the metallic heat conducting layer (3) in the form of a metal foil (8) is formed. Wärmeleitanordnung (1) according to at least one of the preceding claims, characterized in that the metal foil (8) formed metallic heat conduction layer (3) has a perforation (9) and / or an embossing. Wärmeleitanordnung (1) according to at least one of the preceding claims, characterized in that the metallic heat conduction layer (3) in the form of a metal network (13) is formed whose mesh size is less than a cross-sectional dimension and / or a minimum length of the metal fiber composite (4) present intact and / or defective metal fibers (5). Wärmeleitanordnung (1) according to at least one of the preceding claims, characterized in that the metallic heat conducting layer (3) on its the metal fiber composite (4) side facing a bonding agent layer (10) via which the heat conduction layer (3) with the metal fiber composite (4) cohesively connectable. Wärmeleitanordnung (1) according to at least one of the preceding claims, characterized in that the adhesion promoter layer (10) consists of a hard or weichlötbaren metal and / or a metal alloy or a thermal adhesive. Wärmeleitanordnung (1) according to at least one of the preceding claims, characterized in that the heat conducting arrangement (1) on the metal fiber composite (4) facing away from the heat conducting layer (3) has an electrical insulation layer and / or an electrical insulation layer. Battery arrangement (20) having a battery (21), wherein the battery (21) has at least one battery cell (22) and a housing (23), and a cooling device (24) arranged on the housing (23) of the battery (21), characterized in that between the battery cell (22) and the housing (23) and / or between the housing (23) of the battery (21) and the cooling device (24) at least one heat conducting arrangement (1) is arranged according to at least one of the preceding claims ,

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