DE102019103049B4 - Battery case and method of making a battery case - Google Patents

Abstract

Battery housing, in particular for an HV battery, comprising:a first housing part (1);a second housing part (2);a contact layer (5) which is arranged between the first housing part and the second housing part and has an electrically conductive and elastic material; andan adhesive layer (3) which is arranged between the first housing part (1) and the second housing part (2), with an area between the first and the second housing part (1, 2) in which the contact layer (5) is arranged, is separated by a web of material (7) formed in the first or second housing part (1, 2) from a region between the first and second housing part (1, 2) in which the adhesive layer (3) is arranged.

Description

The present invention relates to a battery housing, in particular for HV batteries, and a method for producing the corresponding battery housing.

To ensure EMC (electromagnetic compatibility), the housings currently used for electrical HV components (e.g. HV battery of an electric or hybrid vehicle) require, among other things, an electrical contact between the housing cover and the housing shell so that the surface of the housing surrounding the battery cells forms a large-area equipotential -Area can act. This is to prevent other devices from being disturbed by unwanted electrical or electromagnetic effects.

In many applications, electrical contact is currently made via a bare metallic contact between the components involved, for example between a housing cover and a housing shell, with surface contact being ensured by means of surface pressure. In order to reliably establish this surface contact required for EMC and to maintain it stably over the service life of the component, a large number of screw connections are used, which are arranged between the housing cover and housing shell. For example, it is quite common for screw connections to be provided at a distance of 7 cm from one another along a contact point between the corresponding components (e.g. between the housing cover and housing frame).

Such contacts between components brought about by surface pressure not only require the large number of screw connections, which unnecessarily increase the system weight. They can only be loosened again with difficulty, for example for maintenance purposes, and also provide a relatively rigid connection which does not permit any relative movement between the housing parts which are screwed together. Since the surface pressure can also vary along the contact surface, the contact between the components that are screwed together can be impaired in areas between the screw connections, in particular due to the influence of vibrations or thermal expansion. This in turn can have a negative impact on the tightness and thus on the corrosion protection of the battery housing.

From pamphlet EP 2 385 274 A1 a seal for a housing is known, in particular for a battery housing or for another electrochemical energy store, comprising a base body, the base body having profile seals with profiled sealing surfaces and the profile seals having first ends and second ends.

pamphlet DE 10 2013 200 560 A1 discloses a battery with a multiplicity of rechargeable galvanic cells, a housing and a cover plate which covers an opening in the housing, a sealant being arranged in an adhesive joint between the cover plate and the housing.

pamphlet DE 3930377 A1 discloses an electromagnetic shielding gasket comprising a body made of plastic and a conductive layer vapor-deposited on the surface of the body.

From pamphlet JP H03 108 400 A there is known an electromagnetic shielding sealing tape comprising a flexible metal foil, a conductive adhesive layer in which conductive particles are dispersed and bonded to the flat surface of the metal foil, and a release paper bonded to the metal foil-facing surface of the conductive adhesive layer.

pamphlet DE 197 29 435 A1 discloses a seal between two metallic components, which is surrounded by a metal foil in order to fulfill the protective conductor function according to DIN VDE 01000 Part S40.

The invention is therefore based on the object of providing a battery housing with good EMC, in which at least some of the disadvantages mentioned above are overcome.

A solution to this is provided by a battery housing and the associated manufacturing method according to the independent patent claims. Further configurations result from the dependent patent claims and the accompanying description.

According to the invention, the battery housing has a first housing part, a second housing part and a contact layer which is arranged between the first housing part and the second housing part and has an electrically conductive and elastic material. The battery housing also has an adhesive layer, which is arranged between the first housing part and the second housing part, with an area between the first and second housing parts, in which the contact layer is arranged, being covered by a material web formed in the first or second housing part Area between the first and the second housing part is separated, in which the adhesive layer is arranged. The web of material can serve as a bearing surface for the corresponding other housing part, so that the first housing part and the second housing part are kept at a predetermined distance from one another. As a result, the maximum degree of compression or deformation of the adhesive layer and/or the contact layer can be adjusted.

The contact layer can, in particular, be designed in the manner of a strip and can be arranged along a contact surface between the first and second housing part. The electrically conductive and elastic material can also be adhesive or bonded. In other words, in addition to providing an electrical connection between the housing parts, the material can also provide an adhesive force which connects the two housing parts to one another. The battery housing can be any desired battery housing, which can have electronic components and battery cells in its interior, for example. In particular, this can be a battery housing of an HV battery for a hybrid or electric vehicle.

The basic idea behind the battery housing according to the invention is to replace the contact between metallic surfaces of the housing parts, which is usually based on surface pressure, with an electrically conductive and elastic material, which is also preferably adhesively bonded. In this way, the surface pressure can be completely dispensed with and the screw connections can be omitted. This results on the one hand in weight and cost savings. On the other hand, the solution proposed here generally results in a more robust system in terms of tightness and corrosion protection, in which, however, a relative movement of the housing components is made possible at the same time. Due to the contact layer between the two housing parts described here, the Flowdrill screws (flow-hole-forming screws) usually required for EMC contacting can be omitted, the number of which is in the order of 100 pieces and more in a large battery housing.

According to further exemplary embodiments of the battery housing, the contact layer arranged between the first and second housing parts seals the housing from the outside. By using the flexible material, components with greater tolerances can be used, since the flexible material can compensate for any unevenness that may be present at the interface between the housing components.

According to further exemplary embodiments of the battery housing, the first housing part can be a housing cover and the second housing part can be a housing shell or a housing frame. The material forming the sealing contact layer can generally be placed between any housing parts between which an electrical connection is to be formed.

According to further exemplary embodiments of the battery housing, the material can have an electrically conductive non-hardenable (non-hardening) sealing compound. A non-curable sealing compound can be understood to mean a permanently elastic sealing compound that is provided, for example, on the basis of a self-adhesive gap filler, which is usually used to form a thermally conductive contact between two components, with an electrically conductive filler or on the basis of an adhesive tape with a foamed carrier material can. The sealing compound can connect the two housing components to one another in an electrically conductive manner via adhesion and cohesion. The use of such a sealing compound has the advantage that the component connection created by it can be released again by applying a release force that overcomes the adhesive force. In addition, the sealant can be removed without leaving any residue if required. In general, a planar contact for the electrical connection between the first and second housing component can be created by means of the sealing compound.

According to further exemplary embodiments of the battery housing, the contact layer can have a molded part which has an elastic material on which an electrically conductive coating is arranged at least in a partial area of its surface, the partial area providing a conductive connection between the first and the second housing part. The elastic material of the molded part can in particular have a foam. Since the electrical conductivity is provided by the electrically conductive material arranged on the surface of the molded part, the foam itself does not necessarily have to be electrically conductive (although it can be). As a result, costly electrically conductive fillers can be saved.

The electrically conductive material, which is arranged on the surface of the molded part, can be two-dimensional (xy) or two-dimensionally conductive. Although there are currently materials with electrical conductivity in all three spatial directions (xyz), the maximum layer thickness in the z-direction is usually limited to less than 1 mm for technological and economic reasons. By applying a two-dimensional conductive contact layer to the surface of the elastic molded part can have electrical conductivity in the z-direction by appropriate selection of the geometric shape of the molded part, since the current in the z-direction of the molded part is readily transported through the two-dimensional electrically conductive coating. The molded part can therefore provide electrical conduction in the z-direction, with the actual electrical conduction taking place through the only two-dimensionally conductive coating.

According to further exemplary embodiments of the battery housing, the molded part can have a cuboid shape and the conductive coating can be arranged at least on contiguous parts of its two surfaces in contact with the first and second housing parts and on a side surface arranged between these surfaces. In other words, the molded part can be cuboid and have the electrical coating on its upper side, its lower side and the side surface lying in between. The coating can thus be arranged in the form of an angular C-shape on the surface of the cuboid molded part. The electrical conductivity of the molded part as an overall structure in the z-direction, i.e. along its thickness, is achieved by the C-shaped arrangement of the electrically conductive material, with the z-direction being able to be essentially parallel to the distance (or distance vector) between the two housing parts. As a result, the electrical conductivity of the molded part depends only to a very small extent on its thickness, since the current conduction takes place in this direction through the two-dimensionally conductive coating. This property can be used particularly advantageously for large components to compensate for tolerances in the z-direction.

According to further exemplary embodiments of the battery housing, the molded part can be produced by means of a surface conductive adhesive tape. The adhesive tape can have a carrier layer, which is usually non-adhesive, and an electrically conductive layer arranged thereon and adhesive. To form the shaped part, a piece of adhesive tape can be folded in such a way that the two adhesive tape parts lie against one another with their carrier layer. This also creates a structure which, due to its geometric structure, is electrically conductive in the z-direction, although the adhesive tape as such is only electrically conductive over its entire surface. Electrical contacting designed in this way reliably establishes the electrical contacting between the housing parts through the adhesive effect acting from the outside, in particular without having to resort to screws. However, the housing parts can also be joined to one another by means of screws, snap-in mechanisms or adhesives, with these other means not being dependent on an electrical contact effect. Furthermore, a molded part designed in this way ensures that the electrical contact layer cannot slip between the two housing parts. In addition, the thickness of the adhesive tape is largely variable, since the electrical conductivity is not provided by the foam or filling material, but by the C-shaped conductive coating. In still other exemplary embodiments, the electrically conductive adhesive tape can be glued to the surface of a foam material, which does not necessarily have to be electrically conductive in order to obtain a molded part that is electrically conductive in the z-direction.

In further exemplary embodiments, a method for producing a battery housing, in particular an HV battery housing, is provided, it being possible for the method to be used in particular for producing the battery housing described above. The method includes providing a first housing part, providing a second housing part, providing a contact layer made of an electrically conductive and elastic material between the first housing part and the second housing part, and providing an adhesive layer which is arranged in an area between the first housing part and the second housing part is separated from a region between the first and the second housing part, in which the contact layer is arranged, by a web of material formed in the first or second housing part.

According to further exemplary embodiments, the method can also include joining the first or second housing part to the corresponding other housing part, with the contact layer being arranged in such a way that it seals the battery housing from the outside.

According to further exemplary embodiments of the method, the provision of the contact layer can include the provision of a non-curable or permanently elastic sealing compound.

According to further exemplary embodiments of the method, providing the contact layer can include providing a molded part which has an elastic material on which an electrically conductive coating has been arranged at least in a partial area of its surface, the partial area having a conductive connection between the first and the second Housing part provides.

According to further embodiments of the method, the molded part can be provided by folding an adhesive tape strip, which has a conductive adhesive (adhesive) side and an insulating side, and the two obtained Parts of the adhesive tape strip are glued to the two housing parts with their adhesive sides. As a result, a secure electrical connection is formed between the two housing parts, which is in particular secured against slipping by the external adhesive effect of the folded adhesive tape.

It goes without saying that the features mentioned above and those still to be explained below can be used not only in the combination specified in each case, but also in other combinations or on their own, without departing from the scope of the present invention.

• 1 zeigt einen Teil eines gewöhnlichen Batteriegehäuses.
• 2 zeigt eine Ausführungsform des Batteriegehäuses gemäß der vorliegenden Erfindung.
• 3A zeigt eine mögliche Struktur der zum Aufbau des erfindungsgemäßen Batteriegehäuses verwendeten Kontaktschicht.
• 3B zeigt eine weitere mögliche Struktur der zum Aufbau des erfindungsgemäßen Batteriegehäuses verwendeten Kontaktschicht sowie ihr Herstellungsverfahren.
• 4 zeigt eine weitere Ausführungsform des Batteriegehäuses gemäß der vorliegenden Erfindung.

Further advantages and refinements of the invention result from the description and the accompanying drawings.

• 1 shows part of a common battery case.
• 2 12 shows an embodiment of the battery case according to the present invention.
• 3A shows a possible structure of the contact layer used to construct the battery housing according to the invention.
• 3B shows another possible structure of the contact layer used to construct the battery housing according to the invention and its manufacturing method.
• 4 12 shows another embodiment of the battery case according to the present invention.

In 1 1 shows part of a conventional battery housing in a cross-sectional view at the coupling point between a housing cover 1 and a housing shell 2. The housing cover 1 rests on a part of the housing shell 2. The electrical connection between the housing cover 1 and the housing shell 2 required for EMC is provided by a surface pressure, which is realized by means of screw connections along the coupling point. In 1 such a screw connection 4 is shown as an example. An adhesive layer 3 is additionally provided between the housing cover 1 and the housing shell 2 . The area to the left of the housing cover 1 and the housing shell 2 in 1 corresponds to the inside of the battery case (HV room) and the area to the right of it corresponds to the outside of the battery case (wet area).

In 2 the coupling point between the housing cover 1 and the housing shell 2 of the battery housing according to the invention is shown in a cross-sectional view. The structure is similar to the structure known from the prior art. However, according to the invention, the surface pressure by means of screw connections 4 is omitted and instead an elastic and electrically conductive contact layer 5 is arranged between the housing cover 1 and the housing shell 2 . The contact layer 5 can be adhesive and thus at the same time develop an adhesive effect on the two housing parts 1, 2 with which it is in contact. The additional adhesive layer 3 can be retained, but is not absolutely necessary in the case of an adhesive contact layer 5 . The contact layer 5 can, for example, have a molded part or a permanently elastic, that is to say non-hardenable, sealing compound. The thickness of the contact layer 5 corresponds to its dimension in the z-direction, the z-direction corresponding to the distance between the housing parts 1, 2 in the area of the contact layer.

An exemplary contact layer 5 is in 3A shown in a cross-sectional view. In this embodiment, the contact layer 5 corresponds to a molded body 6 which has a core 51 made of an elastic material (eg foam). The core material can, but does not have to, be electrically conductive. A conductive layer 52 is arranged on the surface of the core 51 and, in the example shown, covers the upper side, the lower side and the left side surface of the core 51 . A conductive structure is thus effectively created which has an angular C-shape. The molded part 6 can be elongate and arranged at the coupling point between the housing cover 1 and the housing shell 2 of the battery housing. Current transport in the z-direction, i.e. between the two housing parts 1 , 2 adjoining the molded part 6 , occurs when the core 51 is non-conductive through that part of the electrically conductive layer 52 which is arranged on the side face 53 of the molded part 6 . The molded part 6 can thus be formed with any desired thickness without sacrificing the conductivity in the z-direction.

An alternative embodiment of the contact layer 5 is in 3B shown. An electrically conductive adhesive tape 54 is used here as the starting material. The adhesive tape 54 has an electrically conductive and adhesive first side or layer 55 which is arranged on a second side or layer 56 . The second side 56 comprises a backing material which is typically non-adhesive. The adhesive tape 54 is therefore conductive over its entire surface in the plane defined by the first side 55 . Perpendicular thereto, the adhesive tape 54 is not conductive. The contact layer 5 is formed by folding the adhesive tape 54, sections of the second side 56 being placed against one another, so that overall a contact layer 5 is formed, which corresponds to that in 3A shown molding 6 is similar. In the 3B The contact layer 5 shown also has an inner core, which is formed by the two contacting second sides 56, and an outer electrically conductive adhesive layer 59 corresponding to the conductive adhesive first side 55 of the adhesive tape 54 . A molded part designed in this way has the advantage that the electrical contact cannot slip between the two housing parts 1 , 2 . There are therefore no screws for forming the electrical contact between the two housing parts 1, 2, since no material has to be pressed.

A further embodiment of the contact layer 5 can be obtained by gluing the electrically conductive adhesive tape 54 onto a material core, for example a foam core. In this way, in particular, thicker contact layers 5 can be produced, that is to say with a greater extent in the z-direction.

In 4 the coupling point between the housing cover 1 and the housing shell 2 according to a further embodiment of the battery housing according to the invention is shown in a cross-sectional view. The structure is similar to that in 2 shown structure with the difference that the area in which the contact layer 5 is arranged is separated by a material web 7 from the area in which the adhesive layer 3 is provided. In this embodiment of the battery housing, too, the contact layer 5 can consist of the molded part described above 3A and 3B correspond or have a permanently elastic, i.e. non-hardenable sealing compound.

Claims (12)

Battery housing, in particular for an HV battery, having: a first housing part (1); a second housing part (2); a contact layer (5) arranged between the first housing part and the second housing part, which has an electrically conductive and elastic material; and an adhesive layer (3) which is arranged between the first housing part (1) and the second housing part (2), with an area between the first and the second housing part (1, 2) in which the contact layer (5) is arranged, is separated by a web of material (7) formed in the first or second housing part (1, 2) from a region between the first and second housing part (1, 2) in which the adhesive layer (3) is arranged. Battery case according to claim 1 , wherein the contact layer (5) arranged between the first and second housing parts (1, 2) seals the housing from the outside. Battery case according to claim 1 or 2 , wherein the first housing part (1) is a housing cover and the second housing part (2) is a housing shell or a housing frame. Battery housing according to one of Claims 1 until 3 , wherein the material comprises an electrically conductive non-curable sealant. Battery housing according to one of Claims 1 until 3 , wherein the contact layer (5) has a molded part (6) which has an elastic material (51) on which an electrically conductive coating (52) is arranged at least in a partial area (53) of its surface, the partial area (53) provides a conductive connection between the first and the second housing part (1, 2). Battery case according to claim 5 , wherein the elastic material comprises a foam. Battery case according to claim 5 or 6 , wherein the molded part (6) has a cuboid shape and the conductive coating (52) is arranged at least on continuous parts of its two surfaces in contact with the first and second housing part and a side surface arranged between these surfaces. Method for manufacturing a battery case, in particular a HV battery case, comprising: providing a first housing part (1); providing a second housing part (2); Providing a contact layer (5) made of an electrically conductive and elastic material between the first housing part (1) and the second housing part (2); and Providing an adhesive layer (3), which is arranged in an area between the first housing part (1) and the second housing part (2), which is formed by a material web (7) in the first or second housing part (1, 2) from an area is separated between the first and the second housing part (1, 2), in which the contact layer (5) is arranged. Process for manufacturing the battery case claim 8 , further comprising: joining the two housing parts (1, 2), wherein the contact layer (5) is arranged such that it seals the battery housing to the outside. Process for manufacturing the battery case claim 8 or 9 , where the ready provide the contact layer (5) has the provision of a non-curable sealing compound. Process for manufacturing the battery case claim 8 or 9 , wherein the provision of the contact layer (5) includes the provision of a molded part (6) which has an elastic material (51) on which an electrically conductive coating (52) has been arranged at least in a partial area (53) of its surface, wherein the partial area (53) provides a conductive connection between the first and the second housing part (1, 2). Process for manufacturing the battery case claim 11 , wherein the shaped part (6) is provided by folding an adhesive tape strip (54) which has a conductive adhesive side (55) and an insulating side (56) and the two obtained parts of the adhesive tape strip with their adhesive sides (55) be glued to the two housing parts (1, 2).

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