DE102022100742B4 - Interface for liquid- and gas-tight connection of a battery system to a motor vehicle body - Google Patents

Abstract

Interface for the liquid- and gas-tight connection of a battery system (3) to a body (5) of a motor vehicle (7), wherein the interface (1) has a first connecting element (11) on the battery system side with a first connection area (12) for connection to the battery system (3) and a second connecting element (21) on the body side with a second connection area (22) for connection to the body (5), wherein the first and second connecting elements (11, 21) are connected so as to be movable relative to one another by means of a liquid- and gas-tight, elastic intermediate member (15).

Description

The invention relates to an interface for the liquid- and gas-tight connection of a battery system to a body of a motor vehicle according to the preamble of claim 1. Furthermore, the invention relates to a motor vehicle with a battery system, a body and such an interface.

For example, in the EN 10 2017 206 986 A1 an interface arranged between battery modules or a battery system and a motor vehicle is disclosed, which interface has connections such as electrical lines or a pipe for the circulation of a fluid. Via such an interface, the battery modules and the motor vehicle can be supplied with electrical, hydraulic and mechanical devices necessary for the functionality of the motor vehicle. The battery modules are attached to the underside of a body with the aid of a protective cover on the motor vehicle. The motor vehicle has fastening and positioning devices for positioning and aligning the battery modules, which specify the exact position and alignment of the battery modules. However, if the battery modules are inadequately positioned and/or aligned - for example due to manufacturing tolerances, bending of the fastening and positioning devices during transport or assembly errors, etc. - connection problems can arise between the body and the battery arrangement. Furthermore, leaks can occur at the interface, which in extreme cases can endanger vehicle occupants.

A generic interface for the liquid- and gas-tight connection of a battery system to a body of a motor vehicle is known from EN 10 2018 206 836 A1 known.

Against this background, the task is to provide an interface for connecting a battery arrangement to a body of a motor vehicle, which can compensate for any assembly, positioning and alignment errors of the battery arrangement relative to the body.

The object is achieved by an interface for the liquid- and gas-tight connection of a battery system to a body of a motor vehicle, wherein the interface has a first connecting element on the battery system side with a first connection area for connection to the battery system and a second connecting element on the body side with a second connection area for connection to the body, wherein the first and second connecting elements are connected so as to be movable relative to one another by means of a liquid- and gas-tight, elastic intermediate member, and wherein the intermediate member is designed according to the invention as a bellows.

Due to the fluid-tight design of the interface according to the invention, the passenger compartment can be protected from external influences such as the entry of gas, liquid and/or solid bodies. Furthermore, positioning and alignment errors of the battery system can be compensated for by the elastic intermediate member according to the invention between the first and second connecting elements, since the intermediate member designed as a bellows enables a relative movement between the first and second connecting elements due to its elastic nature.

The bellows can be made of an elastomer such as silicone rubber in order to have rubber-elastic properties. In addition, regardless of the elasticity of the bellows material, a relative movement between the two connecting elements can be made possible by simply unfolding the bellows, without making any concessions with regard to the tightness of the interface. Overall, tolerance compensation can be achieved in all three spatial directions between the two connecting elements or between the battery system and the body.

A preferred embodiment of the invention provides a first sealing element for sealing against the battery system. The first sealing element can effectively seal a wet space in which the battery system is arranged from the passenger compartment. The sealing element can also be made of an elastomer.

A further preferred embodiment of the invention provides a second sealing element for sealing against the body. The second sealing element can also be made of an elastomer and can separate the passenger compartment from the wet area. The second sealing element can in particular be used at the same time as the first sealing element, thus increasing the overall tightness of the interface. The spatial distance between the first and second sealing elements can also create a gap, which can lead to a further increase in the sealing effect. Particles and fluids that may have passed through the first sealing element can become trapped and deposited in the said gap.

An advantageous embodiment of the invention provides that the intermediate member and the first sealing element are formed in one piece. The one-piece design can make an additional manufacturing step unnecessary, since only one part is manufactured instead of two. In analogy to an unnecessary manufacturing step, an assembly step can also be omitted. Overall, this can save time in production.

A further advantageous embodiment of the invention provides that the intermediate member and the second sealing element are formed in one piece. Analogous to the one-piece design of the intermediate member and the first sealing element, manufacturing steps and thus time can be saved by the one-piece design of the intermediate member and the second sealing element.

A particularly preferred embodiment provides that the intermediate member, the first sealing element and the second sealing element are formed in one piece. The highest manufacturing and assembly efficiency can be achieved by the one-piece design of the intermediate member, the first and the second sealing element. This is equivalent to the fact that the intermediate member comprises the first and the second sealing element.

According to a preferred embodiment, it is provided that the bellows is arranged at least partially along a first outer contour of the first connecting element, wherein the second connecting element is arranged at least partially along a second outer contour of the bellows. By arranging the bellows on an outer contour of the first connecting element, the orientation of the first connecting element in relation to the second connecting element can be changed with the bellows folding in several spatial directions. Furthermore, the bellows in such an arrangement can be understood as an extension of the first connecting element, whereby a larger area and volume can be used between the battery system and the body, thus contributing to the tightness of the interface. Furthermore, the bellows can be connected to an inner contour of the second connecting element via an outer contour. This arrangement can create a hermetic connection between the first and the second connecting element.

An advantageous embodiment of the invention provides that the first connecting element has at least one through hole. The through hole according to the invention allows the battery system to at least partially protrude through the first connecting element of the interface in order, for example, to enable the electrical connection of the battery system to the motor vehicle via suitable plugs via the protruding section of the battery system. Furthermore, several through holes can be formed in the first connecting element in order, for example, to guide high-voltage and low-voltage lines through separate recesses in the interface.

A preferred embodiment provides a first sealing element for sealing against the battery system, which is arranged on an inner contour defined by the through hole. By arranging a - in particular elastic - sealing element on the inner contour, the interface can ensure an effective sealing effect against the battery system. The sealing effect can be achieved by the physical contact between the sealing element and the battery system section protruding through the through hole.

According to an advantageous embodiment, the first connecting element has at least one at least partially tubular connection for the flow of a liquid medium - in particular a cooling medium - whereby the connection is formed in one piece with the first connecting element. Since battery systems in motor vehicles require thermal management, such connections may be required for controlling the temperature of the battery system. A cooling medium, which can be guided through suitable pipes, can flow through the interface through a first coolant connection to the battery system. The cooling medium, which has been heated up as a result of circulation, can flow through the interface in the opposite direction via a second coolant connection.

An advantageous embodiment of the invention provides that the first and second connecting elements are made of a glass fiber reinforced plastic (GRP), in particular of polyamide 66 with a glass fiber content of 25% (PA66 GF25). By using PA66 GF25, good properties with regard to electrical insulation, chemical corrosion resistance and strength of the connecting elements attached to the battery system and the body can be achieved for the application according to the invention. In addition, a glass fiber reinforced plastic with polyamide 66 and a glass fiber content of 25% has flame retardant properties.

A preferred embodiment provides that the interface is produced in a multi-component injection molding process. By means of the multi-component injection molding process, the The bellows are sprayed onto the previously sprayed first and second connecting elements, creating a one-piece interface. Subsequent assembly steps are not necessary, as the bellows do not have to be pulled separately onto the connecting elements and screwed, glued or otherwise joined to them.

A further subject of the invention is a motor vehicle with a battery system, a body and an interface according to one of the preceding embodiments. Such a motor vehicle can be operated with an electric drive system. Furthermore, the battery system can be easily connected to the motor vehicle using the interface, which is error-tolerant with regard to alignment. Furthermore, a good seal can be achieved between the battery system and the motor vehicle. In addition, the interface can be made at least partially from materials with flame-retardant properties, thus preventing the entry of flames into the passenger compartment, at least for a limited period of time.

• 1a eine erfindungsgemäße Schnittstelle in einer perspektivischen Darstellung von oben;
• 1b die erfindungsgemäße Schnittstelle aus der 1a in einer perspektivischen Darstellung von unten;
• 2 die Schnittstelle im montierten Zustand in einer schematischen Darstellung;
• 3 ein Batteriesystem in einer schematischen Darstellung; und
• 4 die Ausrichtung des Batteriesystems aus 3 gegenüber einer Karosserie eines Kraftfahrzeugs unmittelbar vor seiner Montage an der Karosserie in einer schematischen Darstellung.

Further details and advantages of the invention will be explained below with reference to the embodiment shown in the drawings.

• 1a an interface according to the invention in a perspective view from above;
• 1b the interface according to the invention from the 1a in a perspective view from below;
• 2 the interface in the assembled state in a schematic representation;
• 3 a battery system in a schematic representation; and
• 4 the orientation of the battery system 3 opposite a body of a motor vehicle immediately before its assembly on the body in a schematic representation.

In the 1a and 1b the interface 1 is shown in a perspective view from above and below. The interface 1 has a trough-shaped basic form and comprises a first connecting element 11 and a second connecting element 21. Both connecting elements 11, 21 are made of the glass fiber reinforced plastic polyamide 66 with a glass fiber content of 25%.

The first connecting element 11 comprises a first connection area 12. In the first connection area 12, the first connecting element 11 has several, here four, steel bushings 24 with threaded inserts for a screw connection. The first connecting element 11 is connected to the battery system 3 via the first connection area 12 using the bushings 24 and screws.

The second connecting element 21 has a second connection area 22. In the second connection area 22, the second connecting element 21 has several, here eight, steel bushings 24 with threaded inserts for a screw connection. The second connecting element 21 is connected to a body 5 of a motor vehicle 7 via the second connection area 22 using the bushings 24 and screws.

The two connecting elements 11, 21 were partially overmolded with silicone as part of a two-component injection molding process. The silicone is partially designed as a bellows 15. Due to its folds and elastic properties, the bellows 15 enables a relative movement between the first connecting element 11 and the second connecting element 21 in all three spatial directions. Furthermore, a first through hole 41 and a second through hole 42 are formed on the first connecting element 11. The first connecting element 11 has a first sealing element 31 on the outer edge of the first through hole 41. Furthermore, the second connecting element 21 has a second sealing element 32, which is formed on a surface section of the second connecting element 21 and is arranged largely rectangularly. The bellows 15, the first sealing element 31 and the second sealing element 32 are formed as one piece.

Two coolant connections 50 are arranged on the first connecting element 11 and are formed in one piece with the first connecting element 11. The left of the two connections 50 is used to supply coolant to the battery system 3. The right connection 50 is used to remove coolant from the battery system. To avoid a massive construction and therefore to save weight and to increase the mechanical stability of the interface 1, stiffening elements 45 are formed at suitable locations.

In the 2 The interface 1 is connected to the housing 60 by means of four screws 60 2 The interface 1 seals a wet space 62 formed outside the passenger compartment from a dry space 64 of the passenger compartment. The first and second sealing elements 31, 32 are arranged at the interface 1 for sealing. The first sealing element 31 is arranged on an inner contour of the interface 1, the inner contour of the interface 1 being defined by the first through hole 41. A housing section 66 of the battery system 3 protrudes through the first through hole 41 of the interface 1. To achieve the sealing effect against the battery-side wet space 62, the first sealing element 31 lies directly on the housing section 66. The second sealing element 32 seals via a connection of the interface 1 - via the second connection area 22 - to the 2 above arranged body 5 of the motor vehicle 7. A further sealing effect is brought about by the bellows 15, since the bellows 15 prevents the penetration of solid, liquid and/or gaseous substances, in particular flames and smoke, from the wet space 62 into the dry space 64 and thus supports the sealing.

The Indian 2 The connection 50 arranged on the left directs a cooling medium for cooling battery modules to the battery system 3. After flowing through the battery system 3, the cooling medium is directed to the heat dissipation through the 2 right-hand connection 50. Furthermore, a low-voltage line 68 is guided through the second through-hole 42. The low-voltage line 68 is attached to the interface 1 by means of a funnel-shaped connection piece 70. The connection piece 70 also functions as a sealing element in the interface 1. Furthermore, in the 2 a high-voltage connection 72 is shown, which is arranged on the battery system 3.

In the 3 the battery system 3 is shown schematically in a perspective view. The interface 1 is connected by means of the first connecting element 11 and several, here four, screws via the 3 connected to the battery system 3 via a first connection area 12 (not shown).

In the 4 the positioning and alignment of the battery system 3 relative to the body 5 of the motor vehicle 7 is indicated. During pre-assembly, the interface 1 has already been connected to the battery system 3. During the so-called marriage, the battery system 3 is connected to the body 5 by moving the battery system 3 and the body 5 relative to each other along the dash-dot lines.

List of reference symbols

1

interface

3

Battery system

5

body

7

Motor vehicle

11

first connecting element

12

first connection area

15

Intermediate link, bellows

21

second connecting element

22

second connection area

24

Bushings

31

first sealing element

32

second sealing element

41

first through hole

42

second through hole

45

Stiffening elements

50

connections

60

Screws

62

Wet room

64

Drying room

66

Housing section

68

Low voltage line

70

Connector

72

High voltage connection

Claims (13)

Interface (1) for the liquid- and gas-tight connection of a battery system (3) to a body (5) of a motor vehicle (7), wherein the interface (1) has a first connecting element (11) on the battery system side with a first connection region (12) for connection to the battery system (3) and a second connecting element (21) on the body side with a second connection region (22) for connection to the body (5), wherein the first and second connecting elements (11, 21) are connected so as to be movable relative to one another by means of a liquid- and gas-tight, elastic intermediate member (15), characterized in that the intermediate member (15) is designed as a bellows (15). Interface (1) to Claim 1 , characterized by a first sealing element (31) for sealing against the battery system (3). Interface (1) to Claim 2 , characterized by a second sealing element (32) for sealing against the body (5). Interface (1) to Claim 2 , characterized in that the intermediate member (15) and the first sealing element (31) are formed in one piece. Interface (1) to Claim 3 , characterized in that the intermediate member (15) and the second sealing element (32) is integrally formed. Interface (1) to Claim 3 , characterized in that the intermediate member (15), the first sealing element (31) and the second sealing element (32) are formed in one piece. Interface (1) according to one of the Claims 1 until 6 , characterized in that the bellows (15) is arranged at least partially along a first outer contour of the first connecting element (11), wherein the second connecting element (21) is arranged at least partially along a second outer contour of the bellows (15). Interface (1) according to one of the preceding claims, characterized in that the first connecting element (11) has at least one through hole (41). Interface (1) to Claim 8 , characterized by a first sealing element (31) for sealing against the battery system (3), which is arranged on an inner contour defined by the through hole (41). Interface (1) according to one of the preceding claims, characterized in that the first connecting element (11) has at least one at least partially tubular connection (50) for the flow of a liquid medium - in particular cooling medium - wherein the connection (50) is formed in one piece with the first connecting element (11). Interface (1) according to one of the preceding claims, characterized in that the first and second connecting elements (11, 21) are made of a glass fiber reinforced plastic (GRP), in particular of polyamide 66 with a glass fiber content of 25% (PA66 GF25). Interface (1) according to one of the preceding claims, characterized in that the interface (1) is manufactured in a multi-component injection molding process. Motor vehicle (7) with a battery system (3), a body (5) and an interface (1) according to one of the preceding claims.

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