DE102015214652A1 - Means of transport, arrangement and method for cooling a traction battery - Google Patents

Abstract

The invention relates to a means of locomotion, an arrangement and a method for heat dissipation of a traction battery with a heat sink (4) and a battery module (3). The method comprises the steps: - cutting a heat-conducting mat (5), - arranging the heat-conducting mat (5) between the heat sink (4) and the battery module (3) and - pressing the heat-conducting mat (5) by reducing the distance of the heat sink (4 ) and the battery module (3).

Description

State of the art

The present invention relates to a means of locomotion, an arrangement and a method for cooling a traction battery with a heat sink and a battery module. In particular, the present invention relates to a measure for the simultaneous electrical insulation and thermal conductivity increase.

The electrification of passenger transport is currently progressing rapidly. According to one approach, electrochemical energy stores are used which deliver the electrical energy required to operate an electric traction machine. This results in heat loss, which must be dissipated from the energy storage used. Sometimes fluid-conducting heat sink between the units of electrochemical cells (hereinafter "battery module") are provided and thermally connected via thermal grease with these. However, this requires the requirement of additional electrical insulation (eg as a consequence of an electrically insulating lacquer layer).

The bottom of the battery modules is usually uneven due to the positional tolerances of the cells within the module. As a result, the continuous heat transfer from the bottom of the battery module to the cooling plate is not guaranteed over the entire surface. At the same time an electrical insulation must be provided to increase the dielectric strength. Usually so-called "gap fillers" are used in the prior art to transfer the heat and to compensate for tolerances between the components. The usual gap fillers used for heat transfer are not per se electrically insulating to the required extent, so that the cooling plates must be additionally provided with a protective layer (eg a glued foil) to ensure the dielectric strength. This electrical insulation is counterproductive for the cooling of the electrochemical cells, since it has a very poor heat transfer and the cooling of the battery modules can not be guaranteed to the required extent. Gapfiller also have the disadvantage that the battery modules can not be detached without damage from the cooling plates. The exact dosing, especially during reworking, is not guaranteed. It is therefore an object of the present invention to overcome the aforementioned disadvantages. It is a further object of the present invention to simplify the assembly or manufacture of battery modules for traction batteries.

Disclosure of the invention

The object identified above is achieved according to the invention by a method for heat dissipation of a traction battery comprising a heat sink and a battery module. The traction battery can be configured, for example, to drive an electric vehicle. As an electrically driven vehicle, for example, a car, a van, a truck, a motorcycle, an aircraft and / or a watercraft into consideration. First, a heat-conducting mat is cut. In other words, a prefabricated heat-conducting mat is brought to format. Subsequently, the heat-conducting mat is arranged between the heat sink and the battery module for the traction battery. Thus, according to the invention, it is not necessary to apply a viscous thermal compound. Subsequently, the heat conduction mat is pressed by reducing a distance between the heat sink and the battery module. This ensures that the best possible installation of the heat-conducting mat on the surfaces of the heat sink and the battery module is guaranteed. If the heat conduction mat is made elastic, unevenness on the surfaces of the heat sink and of the battery module can be compensated and a best possible heat transfer surface can be provided. In this way, the heat dissipation of the battery module is improved by means of the heat sink and additional electrical insulation of the battery module and the heat sink is unnecessary.

In other words, therefore, instead of a capfiller, a heat-conducting foil is used, which is preferably relatively soft and in particular elastic, so that it can compensate for tolerances and nevertheless be able to meet the requirements of electrical breakdown resistance. Heat-conducting foils usually have an adhesive property (silicone or acrylate-based), so that they can be reliably applied to the battery modules (eg rolled up).

The dependent claims show preferred developments of the invention.

The heat-conducting mat can preferably be rolled onto the heat sink or the battery module. Through the rolling process, air pockets can be minimized. It is irrelevant whether the rolling takes place after application of the heat-conducting mat on the heat sink or the battery module or the rolling is accompanied by the application of the heat-conducting mat. For example, the heat conduction mat can be positioned on the heat sink or the battery module before rolling, before the rolling process avoids air pockets and causes a reduction in the heat transfer resistance.

The arranging of the heat-conducting mat on the battery module can take place in such a way that a self-adhesive layer of the heat-conducting mat is activated, for example by removing a protective layer from the self-adhesive layer of the heat-conducting mat before the self-adhesive layer is applied to the battery module or the heat sink. In this way it is not necessary to apply a fluid / viscous adhesive, which can lead to contamination of mechanical components of the traction battery (eg threads, electrical connections, etc.).

The heat-conducting mat can rest for example directly on the battery module and / or on the heat sink. In other words, there is no further intermediate layer between the heat-conducting mat and the battery module or between the heat-conducting mat and the heat sink. In particular, a layer customary for the purpose of electrical insulation (eg lacquer layer, foil or the like) can be dispensed with according to the invention.

According to a second aspect of the present invention, an arrangement for a traction battery is proposed, which comprises a heat sink, a battery module and arranged between the heat sink and the battery module heat conduction. The battery module contains electrochemical cells, via which electrical energy can be output to a traction machine of a means of locomotion.

Of course, according to the invention, it is not excluded that a plurality of heat sinks and / or a plurality of battery modules and / or a plurality of heat conduction mats are used within the traction battery. The features, combinations of features and the advantages arising therefrom correspond to those of the first-mentioned aspect of the invention so that reference is made to the above statements in order to avoid repetition.

A heat transfer resistance between the heat-conducting mat and the heat sink or the battery module can be reduced, for example, such that a, in particular permanent, mechanical bias between the heat sink and the battery module is generated. This may include, for example, a screw, by means of which the heat sink and the battery module are mechanically connected to each other. Particularly preferably, the screw is oriented in the heat conduction, so that tightening the screw causes a reduction in a distance or an increase in a compressive force between the battery module and the heat sink. In this way, the screw can additionally be used according to the invention to reduce air pockets and compensate for surface irregularities of the heat sink or the battery module.

The edges of the heat-conducting mat can be tailored according to a heat-conductive surface between the heat sink and the battery module. In other words, the contours of the heat-conducting mat in the form of a cut edge correspond to the contours of those surfaces which lie opposite one another in an assembled state between the heat sink and the battery module. In particular, the heat-conducting mat can be cut to such an extent that it does not protrude beyond the contact surface of the heat sink or beyond the contact surface of the battery module. The heat-conducting mat can have cut-outs which are required for fastening (for example by means of a screw connection) of the heat sink to the battery module.

The heat-conducting mat may be a polyester layer and / or an acrylic elastomer layer and / or a soft acrylic elastomer layer and / or an outer layer (English: film liner). in the form of a self-adhesive layer. In particular, the self-adhesive layer may have a silicone base and / or an acrylate base. The components of the heat-conducting mat described above have been found to be advantageous for ensuring a high thermal conductivity and at the same time a high electrical insulation.

The heat sink may be configured, for example, to lead a coolant. For this purpose, the heat sink may have fluid connections and a fluid guide. The fluid guide can be set up to direct the fluid in an ordered form through the heat sink in order to ensure the most uniform possible cooling of all surface areas of the heat sink contacted by the heat conduction mat. In this way, the surface of the battery module is uniformly cooled. The use of a liquid coolant allows a particularly good heat dissipation and thus a particularly high performance and durability of the traction battery.

The heat sink may have, for example, a metallic surface. The same applies to the surface of the battery module. Preferably, the heat-conducting mat provided according to the invention is in direct contact with the metallic surface or with the metallic surfaces. In other words, no lacquer layer is provided to increase an electrical breakdown or electrical insulation.

According to a third aspect of the present invention, a means of transportation (eg, car, van, truck, motorcycle, air and / or water vehicle) is proposed. The means of locomotion is electrically driven and for this purpose has an electric traction machine, which is set up to be supplied with electrical energy via an inventively designed traction battery with an arrangement according to the invention. With regard to the features, feature combinations and advantages, reference is made to the above statements.

A heat-conducting mat which can be used according to the invention is currently offered, for example, by the company 3M (TM) as "Thermally Conductive Acrylic Interface Pad 5590HP-12". This thermal pad is used in the prior art, for example, in televisions, monitors, searchlights and computers. According to the invention, the heat-conducting mat with the self-adhesive side can be pressed onto the battery module from below and glued to it before the possibly enclosed volume of air between the heat-conducting mat and the battery module is reduced or removed by means of a rolling operation in order to ensure a good thermal contact.

Brief description of the drawings

Hereinafter, embodiments of the invention will be described in detail with reference to the accompanying drawings. In the drawings:

1 a schematic representation of an electrically driven means of transport according to the invention with an embodiment of a traction battery according to the invention;

2 a perspective view of an inventively designed arrangement for a traction battery;

3 a sectional view of in 2 shown arrangement;

4 a perspective view of an assembly step in assembling an arrangement according to the invention;

5 an exploded view of an inventively designed arrangement;

6 an assembly step in the manufacture of an embodiment of a traction battery according to the invention;

7 a perspective view of a result of a successful, in 6 illustrated assembly step for producing a traction battery;

8th a perspective view of a nearly fully assembled traction battery according to the invention with a detailed view for attaching a battery module in a floor pan made of die-cast aluminum of a housing of the traction battery; and

9 a schematic representation of the layers of a heat conductive mat used in the invention.

Embodiments of the invention

1 shows a car 10 as an embodiment of an inventively designed electrically driven means of transport. An electric traction machine 2 is set up, via an inventively designed traction battery 1 to be supplied with electrical energy.

2 shows a perspective view of an arrangement 20 , which is a modular component of an in 1 shown traction battery 1 can form. Two battery modules 3 contain (not shown) electrochemical cells, which represent the respective actual energy storage. A power rail 6 connects corresponding electrical poles of the arrangement with each other. A heat sink 4 is between the two battery modules 3 arranged. The heat sink 4 has a connection 22 for a coolant supply and a connection 23 for a coolant discharge. module carrier 7 are with the battery modules 3 screwed to the arrangement 20 mechanically determined in the traction battery. Along a dashed line AA was the following in connection with 3 produced sectional view.

3 shows a sectional view taken along the dot-dash line AA (see 2 ) of an embodiment of an inventive arrangement 20 , The sectional view shows that there is a difference between the battery modules 3 and the heat sink 4 respective heat-conducting mats provided according to the invention 5 Which is a particularly effective cooling of the battery modules 3 or the electrochemical cells contained in these and thus a particularly efficient operation of the arrangement 20 guarantee.

4 shows an assembly step of an assembly of an embodiment of an inventive arrangement 20 in which bolt 9 in holes 21 the battery modules 3 be introduced and with in the module carriers 7 . 8th arranged threads are brought into engagement. The bolts 9 are parallel to Main heat conduction between the battery modules 3 and the heat sink 4 oriented. In the module carriers 8th arranged threaded bushings 12 serve the mechanical fixing of the arrangement 20 within one (in 4 not shown) bottom tray of a housing of a traction battery according to the invention.

5 shows an exploded view of in 4 illustrated arrangement 20 , In this are holes 19 inside the heat sink 4 recognizable, which penetrated in the course of a screwing described above and thus for the mechanical positioning of the heat sink 4 between the battery modules 3 be used. threaded bushings 16 on the module carriers 7 are set up with the threads of the bolts 9 to be engaged to the battery modules 3 to brace each other and here the heat conductivities 5 against the heat sink 4 to squeeze. screw 11 are provided, an electrical and mechanical fixing of the busbar 6 at the (not shown) poles of the battery modules 3 make. Tabs with holes 13 serve the mechanical fixing of a (not shown) electrical line to the traction battery. Essentially horizontally oriented tabs with holes 14 serve the mechanical fixing of the arrangement 20 in the (not shown) bottom tray of the traction battery The module carrier 7 are made as stamped parts and over imprints 15 mechanically stiffened. Also the module carrier 8th have threaded bushings oriented in the direction of heat conduction 16 and screw holes with holes 18 on which of the bolts 9 be penetrated in fully assembled condition. The module carriers 8th show the battery modules 3 facing away from tabs 17 on which a provisional mechanical fixing of the arrangement 20 allow in the battery tray, so that a subsequent screwing the module carrier 7 . 8th can be done easily with the (not shown) floor pan. Also the module carrier 8th have imprints 15 for mechanical stiffening. In particular, the position of a tab, which is substantially vertically oriented threaded sockets 12 are characterized by the imprints 15 stiffened.

6 shows an assembly step of an in 5 described arrangement 20 in a floor pan 30 a traction battery. screw 28 be from a bottom of the floor pan 30 in engagement with vertically oriented threaded bushes 12 the module carrier 8th brought. Then the screws 28 by means of rubber stoppers 29 laminated to prevent corrosion. The screws 28 have a flange themselves 28a , the one circumferential seal 28b having. The circumferential seal 28b is when completely screwed to a bottom of the floor pan 30 pressed. screw bosses 28d are in one area of the floor pan 30 recognizable in which still no inventive arrangements 20 are placed.

7 shows a fully equipped floor pan 30 in which four arrangements 20 have been placed.

8th indicates the presentation in 7 subsequent assembly step, in which tension struts 31 above the orders 20 arranged and with both the heat sinks 4 as well as with the floor pan 30 are bolted. In a detail view (right in the picture) of an assembly area is shown as the threaded bushing 12 of the mounting carrier 8th from the thread of a screw 28 is penetrated. The flange 28a the screw 28 lies on a bottom of a screw dome 28d the floor pan 30 , The rubber stopper 29 closes the cavity of the screw dome 28d in which the flange 28a is arranged. In this way, fluids can neither escape from the bottom pan 30 exit into the floor pan 30 reach.

9 shows a schematic structure of a heat conductive mat used in the invention 5 , A first layer is comparatively thin and comprises a polyester 24 , An adjoining the first layer second layer is considerably thicker and as an acrylic elastomer layer 25 designed. Between the second layer and a fourth outer layer, which acts as a self-adhesive layer 27 is configured and has a silicone base and / or an acrylate, a third layer is added, which has the largest layer thickness in the composite and as a soft acrylic elastomer layer 26 is designed. In particular, the third layer is therefore adapted to compensate for any unevenness present on the surfaces of the heat sink or of the battery module and for a good and homogeneous thermal conductivity of the heat-conducting mat 5 to care. To avoid foamy elements, which would reduce the thermal conductivity due to inherent air pockets, the heat-conducting mat 5 a limited flowable layer (eg, a gel layer), whereby material, which was previously arranged at bottlenecks between the heat sink and the battery module, can escape into an area with a greater distance between the heat sink and the battery module. Preferably, the cutting edges of the heat-conducting mat are welded together before pressing the heat-conducting mat between the heat sink and the battery module. In this way it can be prevented that the flowable material can escape in an inappropriate place. For this purpose, a reservoir or an overflow container may be provided on the heat-conducting mat.

Although the aspects and advantageous embodiments of the invention have been described in detail with reference to the embodiments explained in connection with the accompanying drawings, modifications and combinations of features of the illustrated embodiments are possible for the skilled person, without departing from the scope of the present invention, the scope of protection the appended claims are defined.

LIST OF REFERENCE NUMBERS

1

traction battery

2

electric traction machine

3

battery module

4

heatsink

5

Wärmeleitmatte

6

conductor rail

7, 8

module carrier

9

bolts

10

car

11

screw

12

threaded bushing

13, 14

drilling

15

embossing

16

threaded bushing

17

flap

18, 19

drilling

20

arrangement

21

drilling

22, 23

Fluid supply / drain connections

24

polyester layer

25

Acrylic elastomer layer

26

soft acrylic elastomer layer

27

self-adhesive layer (outer layer)

28

screw

28a

screw flange

28b

rubber seal

28d

screw boss

29

rubber stopper

30

floor pan

31

tension strut

Claims (15)

Method for heat dissipation of a traction battery ( 1 ) with a heat sink ( 4 ) and a battery module ( 3 ) comprising the steps: - cropping ( 100 ) a Wärmeleitmatte ( 5 ), - Arrange ( 200 ) of the thermal conductivity mat ( 5 ) between the heat sink ( 4 ) and the battery module ( 3 ) and - pressing ( 400 ) of the thermal conductivity mat ( 5 ) about a reduction of a distance of the heat sink ( 4 ) and the battery module ( 3 ). Method according to claim 1, wherein the arranging of the heat-conducting mat ( 5 ) - rolling ( 300 ) of the thermal conductivity mat ( 5 ) on a mounted traction battery ( 1 ) the heat sink ( 4 ) facing surface of the battery module ( 3 ). A method according to claim 1 or 2, wherein the arranging takes place such that a self-adhesive layer of the heat-conducting mat ( 5 ) the battery module ( 3 ) is arranged facing. Method according to one of the preceding claims, wherein the heat-conducting mat ( 5 ) on the one hand on the battery module ( 3 ) and on the other hand on the heat sink ( 4 ) is present. Arrangement for a traction battery ( 1 ) - a heat sink ( 4 ), - a battery module ( 3 ) and - one between the heat sink ( 4 ) and the battery module ( 3 ) arranged Wärmeleitmatte ( 5 ). Arrangement according to claim 5, wherein the heat-conducting mat ( 5 ) between the heat sink ( 4 ) and the battery module ( 3 ) is pressed. Arrangement according to one of the preceding claims 5 or 6, wherein the heat-conducting mat ( 5 ) a battery module ( 3 ) arranged facing self-adhesive layer ( 27 ) having. Arrangement according to one of the preceding claims 5 to 7, wherein a normal to a heat conduction direction between the heat sink ( 4 ) and the battery module ( 3 ) oriented screw connection ( 9 . 19 . 21 ) between the heat sink ( 4 ) and the battery module ( 3 ) is provided, which in particular also a module carrier ( 7 . 8th ) on the battery module ( 3 ) attached. Arrangement according to one of the preceding claims 5 to 8, wherein edges of the heat-conducting mat ( 5 ) corresponding to a heat-conductive surface between the heat sink ( 4 ) and the battery module ( 3 ) are tailored. Arrangement according to one of the preceding claims 5 to 9, wherein the heat-conducting mat ( 5 ) - a polyester layer ( 24 ) and / or - an acrylic elastomer layer ( 25 ) and / or - a soft acrylic elastomer layer ( 26 ) and / or - an outer layer in the form of a self-adhesive layer ( 27 ) and / or - has a silicone base and / or an acrylate base. Arrangement according to one of the preceding claims 5 to 10, wherein the heat-conducting mat ( 5 ) has a thickness between 0.5 mm and 1.8 mm, in particular between 1.1 mm and 1.3 mm. Arrangement according to one of the preceding claims 5 to 11, wherein the heat-conducting mat ( 5 ) has a dielectric strength between 6 kV / mm and 14 kV / mm, in particular between 8 kV / mm and 12 kV / mm. Arrangement according to one of the preceding claims 5 to 12, wherein the heat sink ( 4 ) Fluid connections ( 22 . 23 ) and a fluid guide for a coolant. Arrangement according to one of the preceding claims 5 to 13, wherein the heat sink ( 4 ) a metallic surface and / or the battery module ( 3 ) has a metallic surface and the heat-conducting mat ( 5 ) is in direct contact with the metallic surface or surfaces. Means of transport comprising - an electric traction machine ( 2 ) and - a traction battery with an arrangement ( 20 ) according to one of the preceding claims 5 to 14.

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