Battery Arrangement for a Motor Vehicle

A battery arrangement for a motor vehicle includes a battery housing and a cell module that is disposed on a base plate of the battery housing. The cell module has a cell module housing and a plurality of battery cells disposed in the cell module housing and a base of the cell module housing is connected to the base plate of the battery housing by an adhesive compound. The cell module housing is connected to a side wall of the battery housing by an adhesive and the adhesive has a higher shearing resistance than the adhesive compound disposed between a base of the cell module housing and the base plate of the battery housing.

BACKGROUND AND SUMMARY OF THE INVENTION

The invention relates to a battery arrangement for a motor vehicle, having a battery housing and at least one cell module that is arranged on a base plate of the battery housing. The at least one cell module comprises a cell module housing and a plurality of battery cells arranged in the cell module housing. A base of the cell module housing is connected to the base plate of the battery housing by means of an adhesive compound.

CN 112151910 A describes a fluid-cooled battery system for a vehicle in which battery modules are arranged in a housing. The housing comprises a frame surrounding the battery module and a cooling plate that is connected to the frame. The battery modules are arranged on the cooling plate within the frame. On the one hand, the battery modules are adhered to the cooling plate by means of a heat-conducting structural adhesive. On the other hand, the frame is also connected to a top side of the cooling plate by means of the structural adhesive, wherein a welded connection is additionally provided in corner regions of the frame.

It can further be provided for a battery arrangement for a motor vehicle that the cell modules are screwed to the battery housing. A heat-conducting paste can here be arranged between the base of the cell module housing and the base plate of the battery housing. The cell modules can be connected to the battery housing by installing the screws in a screw attachment bar arranged laterally next to the respective cell module housing. In this embodiment, however, a corresponding clearance is provided laterally next to the cell modules to obtain access to the screws with a screwdriver. This is not favorable.

Such a connection of the cell modules to the battery housing only occurring laterally is further not ideal, in particular if the cell modules have a comparatively high weight, as can be the case for cell modules for a battery arrangement of a motor vehicle.

Additionally, in such an arrangement of the cell modules, in which the cell modules are screwed to the screw attachment bar of the battery housing, only a comparatively ineffective side profile is provided with regard to a lateral impression of the battery housing by the respective cell module. This accompanies a comparatively low resistance moment of the battery arrangement. Correspondingly, a mechanical stiffness of the respective cell module is not optimally used for the overall mechanical performance of the battery arrangement when the cell modules are screwed to the battery housing.

Arranging the comparatively expensive heat-conduction paste between the base of the cell module housing and the base plate of the battery housing is additionally connected to comparatively high costs. A large quantity of heat-conduction paste here additionally contributes in a disadvantageous manner to a correspondingly high weight of the battery arrangement.

When a gap or clearance is arranged between the base of the cell module housing and the base plate of the battery housing, tolerances should additionally be taken into account. This results in a comparatively large gap or large clearance between the base of the cell module housing and the base plate of the battery housing. Correspondingly, a comparatively large amount of expensive heat-conduction paste must be used to fill this clearance or gap as completely as possible. As previously explained, this is disadvantageous with regard to the costs and the weight of the battery arrangement.

The object of the present invention is to create a battery arrangement of the type specified in the introduction, in which an improved mechanical connection of the at least one cell module to the battery housing is obtained.

The battery arrangement according to the invention for a motor vehicle comprises a battery housing and at least one cell module. The at least one cell module is arranged on a base plate of the battery housing. The at least one cell module comprises a cell module housing and a plurality of battery cells arranged in the cell module housing. A base of the cell module housing is connected to the base plate of the battery housing by means of an adhesive compound. The cell module housing is further connected to a side wall of the battery housing by means of a further adhesive. The further adhesive here has a higher shearing resistance than the adhesive compound arranged between the base of the cell module housing and the base plate of the battery housing.

The mechanical connection of the at least one cell module to the battery housing is correspondingly ensured by the further adhesive arranged between the side wall of the battery housing and the cell module housing. The further adhesive having the comparatively high shearing resistance specifically carries a main load with regard to mechanical requirements. An improved mechanical connection of the at least one cell module to the battery housing is consequently achieved in the battery arrangement.

In contrast, the lower shearing resistance of the adhesive compound ensures that at least one cell module housing can still be very easily separated from the battery housing in the case of a required demounting. For this purpose, the further adhesive must first be cut through. Due to the good accessibility of this further adhesive, this can be very easily undertaken, however, for example by means of a cutting tool moving back and forth, for example in the form of an oscillating blade.

Following such cutting through of an adhesive layer formed by the further adhesive, the at least one cell module can then be very easily lifted out of the battery housing, for example by means of a lifting tool. This lifting of the at least one cell module from the battery housing is particularly simple, as the adhesive compound only has the comparatively low shearing resistance.

As it is not required to screw the at least one cell module to the battery housing, and in particular to the side wall of the battery housing, it is in particular possible to save costs and save space. This is due to the effective mechanical connection of the cell modules in the overall battery structure, in particular due to the use of the further adhesive having the high shearing resistance.

In this way, it is further possible to keep a gap or clearance between the base of the at least one cell module housing and the base plate of the battery housing particularly small. This applies in particular in comparison with a battery arrangement in which the at least one cell module is screwed to the battery housing. Due to the direct alignment of the at least one cell module on the base plate of the battery housing with the interposition of the adhesive compound, a reduction of the tolerance chain can be achieved. Costs for the adhesive compound and also a quantity of adhesive compound can thus be spared. This contributes to saving weight of the battery arrangement.

If the battery arrangement is used in a motor vehicle, wherein a high-voltage battery is preferably provided via the at least one cell module of the battery arrangement, then such weight saving is particularly advantageous with regard to a CO2balance of the motor vehicle.

Due to the low gap tolerance between the base of the cell module housing and the base plate of the battery housing, a particularly effective cooling of the battery cells received in the cell module housing can additionally be obtained in the operation of the same. In particular, a fast charging ability of the battery cells can thus be improved.

In an advantageous manner, the gap tolerance in the battery arrangement results only from surface shape tolerances of an adhesive surface provided by the base plate of the battery housing and an adhesive surface provided by the base of the at least one cell module housing. As a result, the battery arrangement can be manufactured from a comparatively low quantity of adhesive compound.

The connection of the at least one cell module to the battery housing is further improved with regard to the installation space, as no clearance needs to be provided for accessibility to the screws with a screwdriver. This is because it is not required to screw the at least one cell module to the battery housing due to the use of the further adhesive for connecting the cell module housing to the battery housing.

It is additionally possible to provide an effective contribution to the mechanical performance of the entire battery or the battery arrangement via the cell module housing. Force paths can additionally be formed and effectively used within the battery arrangement via simple solutions. Nevertheless, the at least one cell module can thus be removed just as easily as is the case for a connection of the at least one cell module to the battery housing by means of screws or bolts.

The shearing resistance of the adhesive compound preferably lies in the range from approximately 0.1 MPa to approximately 2 MPa. It has further proved advantageous if the shearing resistance of the further adhesive lies in the range from approximately 5 MPa to approximately 15 MPa. It can thus in particular be achieved that even if a comparatively small adhesive surface is provided, on which the cell module housing is connected to the side wall of the battery housing by means of the further adhesive, a large holding force is created. On the other hand, the comparatively low shearing resistance or low tensile strength of the adhesive compound ensures, in comparison, that a non-destructive removal of the cell modules is guaranteed by pulling away the cell modules upwards in the case of repair or for recycling.

Further advantages, features and details of the invention result from the following description of preferred exemplary embodiments and with reference to the drawings. The features and combinations of features previously specified in the description and the features and combinations of features specified below in the description of the figures and/or shown in the figures alone can be used not only in the respectively specified combination, but also in other combinations or in isolation without leaving the scope of the invention.

DETAILED DESCRIPTION OF THE DRAWINGS

Identical or functionally identical elements are respectively provided with the same reference numerals in the figures.

InFIG.1, a battery arrangement10is highly schematically shown, in which a cell module12is arranged in a battery housing14. The battery housing14comprises a presently trough-shaped receiving part having a base plate16and a side wall18surrounding the base plate16. As is presently shown in exemplary form, the side wall18can in particular be designed as one part with the base plate16of the battery housing14. The battery housing14further comprises a housing cover20that is connected to the trough-shaped receiving part in a manner not presently shown in more detail. The at least one cell module12is arranged within a receiving chamber delimited by the trough-shaped receiving part and the housing cover20.

The at least one cell module12presently has a cell module housing22and battery cells24arranged within the cell module housing22, said battery cells not presently being shown in detail. The individual battery cells24of the cell module12are essentially electrically conductively connected to one another, wherein the battery cells24of the respective cell module12can be electrically switched in series and/or in parallel.

In particular if a high-voltage battery should be provided for a motor vehicle by the battery arrangement10, and thus an electrical energy storage device preferably designed as a traction battery of the motor vehicle, which has a nominal power of more than 60 volts, and in particular of up to several hundred volts, several cell modules12can be electrically conductively connected to one another in the battery housing14.

The cell module housing22comprises a base26facing the base plate16of the battery housing14. An adhesive compound28is arranged between the base26and the base plate16. This adhesive compound28is preferably designed to be able to conduct heat, such that released heat can be effectively emitted via the adhesive compound28from the battery cells24in the operation of the same to the battery housing14or a corresponding cooling device. For example, the heat conductivity of the adhesive compound28can be approximately 2 W/mK, and in particular lie in the region of 2 W/mK to 2.5 W/mK.

The adhesive compound28ensures a certain fixing of the cell module12within the battery housing14. However, a shearing resistance or holding force of the adhesive compound28is preferably dimensioned such that the cell module12can be easily separated from the battery housing14, in particular from the base plate16, again in the case of a repair or exchange of the at least one cell module12. The adhesive compound28preferably has a minimum adherence by which crash requirements and operating strength requirements can be fulfilled. The non-destructive removal of the cell modules12from the battery housing14, and in particular a removal from the trough-shaped receiving part of the battery housing14, is still guaranteed by the comparatively low shearing resistance or tensile strength of the adhesive compound28.

Unlike the adhesive compound28serving as a heat-conducting adhesive, a further adhesive30ensures the structural connection of the at least one cell module12to the battery housing14. The cell module housing22is presently connected to the side wall18of the battery housing14by means of this further adhesive30, which is schematically depicted inFIG.1. This further adhesive30has a very high shearing resistance, which can for example lie in the range of in particular 8 MPa to 14 MPa. Contrastingly, the shearing resistance or tensile strength of the adhesive compound28can in particular lie in the range of approximately 0.5 MPa to 1.5 MPa.

Both the shearing resistance or tensile strength of the further adhesive30serving as a fixing adhesive and the shearing resistance or tensile strength of the adhesive compound28serving as a heat-conducting adhesive can in particular be determined according to DIN EN ISO 527-2.

For the stable fixing of the at least one cell module12in the battery housing14, the further adhesive30is arranged laterally to the cell module12and in particular between a side wall32of the cell module housing22and the side wall18of the trough-shaped receiving part of the battery housing14. The further adhesive30having the high shearing resistance can be cut through, for example by means of an oscillating knife, to demount the cell module12. This is particularly easy, as a good accessibility for a cutting tool of this kind is provided on the sides of the cell module housing22.

The adhesive compound28preferably substantially areally covers the base26of the cell module housing22. A delimiting element can be provided for delimiting a corresponding adhesive surface so that the adhesive compound28is well levelled and a clearance or gap between the base plate16of the battery housing14and the base26of the cell module housing22is filled with the adhesive compound28as evenly as possible.

The delimiting element, for example designed as a sealing cord or sealing tape34, thus delimits the edges of the surface occupied by the adhesive compound28on the base plate16of the battery housing14. The sealing tape34or equivalent delimiting element can here be applied onto the cell module12and/or onto the base plate16before the installation of the at least one cell module12in the battery housing14.

Foam materials are in particular suitable for providing a delimiting element of this kind. If an electrically conductive connection of the cell module12to the base plate16should be provided, then such a foam material can also be metallically laminated. The foam material can correspondingly be surrounded by an electrically conductive metal of the delimiting element.

It can further be seen fromFIG.1that the cell module12can have an energy absorption element36, via which an impact geometry is provided. Such an energy absorption element36can absorb impact energy via deformation in the case of a lateral application of force to the battery arrangement10, and so avoid damage, in particular of the battery cells24. In the embodiment schematically shown inFIG.1, the further adhesive30is arranged between an outside38of the energy absorption element36and the side wall18of the trough-shaped receiving part of the battery housing14.

A possible embodiment of the energy absorption element36in particular designed as one part with the side wall32in the manner of a chamber having a cavity is shown in exemplary form inFIG.2.

Correspondingly, a possible embodiment of a peripheral flange40can be seen fromFIG.3, which can belong to the trough-shaped receiving part of the battery housing14. The housing cover20of the battery housing14(seeFIG.1) can in particular be fixed to such a peripheral flange40.

InFIG.3, a lifting device42is additionally schematically shown, which can be used for the purpose of removing the cell module12from the battery housing14after cutting through the adhesive30. The separation of the base26of the cell module housing22from the base plate16(seeFIG.1) of the battery housing14can thus be obtained by operating the lifting device42. The lifting device42can be operated after the further adhesive30has been cut through, which serves for the structural connection of the cell module12to the battery housing14, and can thus be described as a fixing adhesive.

The lifting device42can comprise a threaded spindle44, for example, wherein the lifting of the base26of the cell module housing22, and thus of the entire cell module12, away from the base plate16of the battery housing14(seeFIG.1) can be achieved by turning the threaded spindle44. It is particularly easy to lift the cell module12out of the trough-shaped receiving part of the battery housing14when such a lifting device42is provided.

By providing the adhesives having different shearing resistances in the form of the preferably heat-conducting adhesive compound28on the one hand and the further adhesive30serving as a fixing adhesive on the other, two joining concepts coordinated with each other are presently provided. The coordinating joining concepts ensure the provision of a sufficient holding force for fixing the cell block or cell module12within the battery housing14for requirements in the normal operation of the battery arrangement10on the one hand, but also for requirements in the case of exceptional events, for example if an accident of the motor vehicle equipped with the battery arrangement10occurs.

The possibility of a non-destructive removal of the at least one cell module12and continued usage of the individual components in the case of a repair is further provided without extensive cleaning of surfaces being required. A sufficient heat removal from the batteries24of the cell modules12to the battery housing14, and in particular an integrated cooling device, is additionally guaranteed.

Possible parameters of the joining concept provided by the heat-conducting adhesive or the adhesive compound28shall be explained in the following in exemplary form. An adhesive able to be obtained from Sika Deutschland GmbH can thus be used as the adhesive compound28, which can be obtained under the brand name Sikaflex®-953 L30. This is a two-component adhesive having a silane-terminated polymer. This adhesive has a tensile strength from 0.5 MPa to 1.5 MPa, and a viscosity of 30+/−20 Pa s. The heat conductivity of this adhesive or this adhesive compound28lies in the range of 2 W/mK to 2.5 W/mK. When using this material, the elongation at break of the adhesive compound28further lies between approximately 20 percent and 50 percent according to DIN EN ISO 527-2.

This adhesive compound28can be extensively applied on the substantially horizontal surface between the base plate16of the battery housing14and the base26of the at least one cell module12. The surface of the base plate16, for example, on which the adhesive compound28is applied does not need to be strictly horizontal, however. Deviations of +10° to −10° from the horizontal can in particular be present.

A joint or gap between the base plate16and the base26is preferably as small as possible in order to guarantee an effective heat removal. A size of the gap can in particular lie in the range from 0.5 millimetres to 3 millimetres.

At the location of this joint, the adhesive compound28is arranged as extensively as possible between the base plate16of the battery housing14and the base26of the respective cell module housing22, such that, on the one hand, an even heat transportation and, on the other, an even fixing of the cell modules12can be obtained.

Contrastingly, a two-component adhesive in the form of a polyurethane adhesive can be used for the structural connection by means of the further adhesive30, for example an adhesive able to be obtained from DuPont under the name BETAFORCE™ 9050, which can correspondingly have the identification BF9050. This adhesive has a viscosity of less than 1 Pa s and a heat conductivity of less than 0.3 W/mK.

The elongation at break for this adhesive further lies in the range of 150 percent to 250 percent according to DIN EN ISO 527-2. This adhesive additionally has a Shore hardness of approximately less than 100 Shore A and a temperature resistance up to approximately 800 degrees Celsius.

The further adhesive30is preferably applied between the two longitudinal sides of the cell block or cell module12and the battery housing14, and in particular the side wall18, on a substantially vertical surface. The surface does not need to be strictly vertical, however, and in particular deviations from the verticals of +10° to −10° can exist.

The joint in which the further adhesive30is installed preferably has a thickness of at least 1.5 millimetres, taking into account all relevant tolerances. In the case of a repair it is thus possible to introduce a cutting tool, for example an oscillating tool, into this region in order to release the adhesive connection.

The further adhesive30preferably fulfils a strength requirement such that its shearing resistance is at least 8 MPa. In this way, a very high holding force can be applied to a comparatively small surface by the further adhesive30.

In particular in relation to the surface of the base26of the cell module housing22covered by the adhesive compound28, the surface on the side wall32of the cell module housing22covered by the adhesive30is very small, and preferably smaller by a multiple. On the one hand, providing a correspondingly small surface occupied by the further adhesive30is advantageous, so that it is possible to cut through the adhesive30and then to release the cell modules12with a cutting tool of a comparatively short length and low cutting force or within a short process duration.

Large surfaces are further still available in the region of the side walls32of the cell module12, in order to provide measures for a possible case of fault of the battery cells24. Lateral venting or ventilation openings can then be provided very freely on the cell module12or cell block, for example, or a free air chamber can be provided in the region of the side walls32. In particular, measures of this kind allow gases or fluids leaking from at least one of the battery cells24in the case of a thermal event to be guided to corresponding openings of the battery housing14, in particular to be guided in a targeted manner.

The two joining concepts are further preferably separated by the sealing tape34or a corresponding sealing lip and/or foam bead or the like, such that the structural connection can be effectively released again, which is accomplished by the further adhesive30. The delimiting element, for example in the form of the sealing tape34shown in exemplary form inFIG.1, additionally ensures that the heat-conducting adhesive or the adhesive compound28remains on the horizontal surface.

If it is required to clean the adhesive locations, then different measures can be taken. For example, the adhesive compound28can be easily manually removed from the underside of the cell module12or cell module housing22or from the top side of the base plate16using a simple plastic scraper. Residual quantities of the further adhesive30serving as a lateral fixing adhesive can be mechanically removed with a simple sharp tool. In the case of a repair, adhering residual quantities of adhesive additionally do not need to be completely removed. Instead, only a gap height to be provided for renewed insertion of the adhesive compound28or a gap width to be provided for renewed insertion of the further adhesive30need to be taken into account.

As an alternative to the products presently specified in exemplary form for providing the adhesive compound28and the further adhesive30, products, for example from Polytec PT GmbH, can be used for the heat-conduction adhesive or the adhesive compound28, for example a product of the type VP2108, which has a strength or shearing resistance of 0.5 MPa at a heat conductivity of approximately 2.5 W/mK. Further, thermally conductive adhesives can also be obtained from the company Polytec PT GmbH for providing the adhesive compound28, for example an epoxy resin-based adhesive with boron nitride as a filler, which has the identification TC433.

Products for providing the adhesive compound28can further be obtained from the company Copaltec, for example of the type ST25or ST30. Such polyurethane potting compounds advantageously also have a low strength or shearing resistance in the region of 2 MPa in the case of a heat conductivity of approximately 1.5 W/mK.

For the further adhesive30used as a fixing adhesive, products from the company Rühl can in particular be used, for example a product of the type Purocast 765, which has a shearing resistance of 3 MPa to 10 MPa.

Furthermore, a product of the type PU10cast, for example from the company L&L Products, can be used for providing the further adhesive30, said product having a shearing resistance of approximately 10 MPa.

LIST OF REFERENCE CHARACTERS