BATTERY SYSTEM FOR AN ELECTRONICALLY OR SEMI-ELECTRICALLY DRIVEN VEHICLE

Abstract

A battery system for an electrically or semi-electrically driven vehicle, in particular for a passenger car. The battery system includes at least two battery modules, each having a module housing and a plurality of battery cells arranged in the module housing. The battery system includes a cooling system for cooling the battery cells. The battery system includes a busbar, wherein the at least two battery modules are connected to one another by the busbar. The battery system includes a busbar housing configured outside of the module housing, wherein the busbar is arranged in the busbar housing and is thermally coupled to the busbar housing. The busbar housing is thermally coupled, at least in portions, to at least one of the battery modules, preferably to the module housing of the at least one battery module.

Claims

1. A battery system for an electrically or semi-electrically driven vehicle, said battery system comprising: at least two battery modules, each having a module housing and a plurality of battery cells arranged in the module housing, a cooling system for cooling the battery cells, a busbar connecting the at least two battery modules, a busbar housing positioned outside of the module housings, wherein the busbar is arranged within the busbar housing and is thermally coupled to the busbar housing, wherein the busbar housing is thermally coupled, at least in portions, to at least one of the battery modules.

2. The battery system according to claim 1, wherein the busbar housing is thermally coupled, at least in portions, to the module housing of both battery modules.

3. The battery system according to claim 1, wherein a plurality of busbars are arranged in the busbar housing.

4. The battery system according to claim 1, wherein the busbar housing comprises a lower shell and an upper shell, which are releasably connected to one another.

5. The battery system according to claim 1, wherein the thermal coupling between the busbar and the busbar housing is effected via a deformable heat conducting element in the form of either a gap pad or a gap filler that is arranged between the busbar and the busbar housing.

6. The battery system according to claim 1, wherein the busbar is thermally coupled to the busbar housing on at least two sides of the busbar, and is thermally coupled to the busbar housing on opposite sides of the busbar.

7. The battery system according to claim 1, wherein a plurality of busbars are arranged in the busbar housing, and the busbars in the busbar housing are mechanically held in a bearing structure, wherein the bearing structure is thermally coupled to the busbar housing.

8. The battery system according to claim 1, wherein the module housing comprises a connecting portion that projects outwardly on an outside of a housing wall of the module housing, wherein the busbar housing is mechanically connected to the module housing in a region of the connecting portion.

9. The battery system according to claim 1, wherein the cooling system comprises a heat sink mounted on an outer side of the module housing facing away from the battery cells, the heat sink being perfusable by a coolant, wherein the busbar housing and the heat sink are thermally coupled to one another only indirectly via a wall of one of the module housings.

10. The battery system according to claim 1, wherein the respective module housing comprises a terminal opening for establishing an electrical connection with the busbar, wherein a terminal element passes through the terminal opening, wherein the module housing comprises a sealing portion circumferentially enclosing the terminal opening, wherein the busbar housing sealingly cooperates with the circumferentially enclosing sealing portion.

11. The battery system according to claim 1, wherein the busbar housing is thermally coupled, at least in portions, to the module housing of the at least one battery module.

12. The battery system according to claim 1, wherein the busbar housing is thermally coupled, at least in portions, to the module housing of all of the battery modules.

13. A motor vehicle comprising the battery system of claim 1.

14. The motor vehicle of claim 13, wherein the motor vehicle is a passenger car.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In the following figures, the invention is explained in further detail with reference to exemplary embodiments, without being limited thereto. The figures show:

[0036] FIG. 1 depicts a first embodiment of the battery system in a sectional view,

[0037] FIG. 2 depicts a second embodiment of the battery system in a sectional view,

[0038] FIG. 3 depicts a third embodiment of the battery system in a sectional view,

[0039] FIG. 4 depicts a fourth embodiment of the battery system in a sectional view,

[0040] FIG. 5 depicts a further embodiment of the battery system in a top-down view,

[0041] FIG. 6 depicts the embodiment according to FIG. 5 without a busbar housing in a top-down view.

DETAILED DESCRIPTION OF THE INVENTION

[0042] FIGS. 1 to 6 show embodiments of the battery system 1 according to aspects the invention, wherein the illustrations of FIGS. 1 to 6 are merely schematic representations. The illustrations are schematic and simplified so as to depict the essential components of the battery system 1.

[0043] The X-axis shown in the figures points in the longitudinal vehicle direction, namely in the direction of travel, the Y-axis corresponds to a transverse vehicle direction, and the Z-axis corresponds to a vertical vehicle direction.

[0044] FIG. 1 shows a battery system 1 for an electrically or semi-electrically driven vehicle, in the present case for a passenger vehicle, in a sectional view in a simplified illustration. The battery system 1 comprises a plurality of battery modules 2 arranged in succession in the longitudinal direction X. The respective battery module 2 comprises a rectangular module housing 3 in cross-section and a plurality of battery cells 4 arranged in the module housing 3. The battery cells 4 are gathered together in order to form battery cell stacks. The battery module 2 shown in FIG. 1 comprises two battery cell packs arranged adjacent one another in the transverse direction Y of the vehicle. The battery system 1 comprises a cooling system for cooling the battery cells 4. Such cooling systems are well known from the prior art, so that only the components of such a cooling system relevant to the present invention will be discussed in further detail below. The cooling system comprises a cooling circuit that is perfused by a coolant, wherein the coolant serves to take up heat from the battery cells 3 and dissipate the acquired heat to a heat sink of the cooling system. The battery cells 4 are thus cooled by means of the cooling system. Typically, in operation, the battery cells are cooled to a temperature below 60° C. and are typically held in the range of 20° C. to 30° C.

[0045] The battery modules 2 are electrically connected to one another by means of a plurality of busbars 5 extending in the longitudinal direction X. The battery system 1 comprises a busbar housing 6, wherein the busbars 5 are arranged in the busbar housing 6. In the present case, the busbar housing 6 is linearly configured and extends in the longitudinal vehicle direction X, spanning a plurality of battery modules 2 arranged in succession in the longitudinal vehicle direction X, as shown by way of example in FIGS. 5. The busbar housing 6 is configured as a separate housing and therefore is not part of the module housing 3. Furthermore, no separate battery housing is provided. The busbar housing 6 extends outside the module housing 3 and is arranged above the module housing 3 in the vertical zo vehicle direction Z.

[0046] For the purpose of cooling the busbars 5, the busbars 5 are thermally coupled to the busbar housing 6, wherein the busbar housing 6 is, in turn, thermally coupled to the module housing 3. The busbars 5 are cooled indirectly via the cooling system of the battery cells 4 by means of the thermal coupling between the busbar housing 6 and the busbars 5 and the thermal coupling between the busbar housing 6 and the module housing 3, because the module housing 3 is cooled directly or indirectly via the cooling system. Due to the fairly long cooling path across the housings 3, 6, the busbars 5 are not cooled as strongly as the battery cells, and a reasonable temperature level for the busbars 5, which is significantly above the temperature level of the battery cells 3, is achieved despite use of the same cooling system.

[0047] In the present case, the busbar housing 6 comprises a lower shell 8 connected to the module housing 3 of the respective battery module 2 and an upper shell 7 releasably connected to the lower shell 8. In the present case, the lower shell 8 is screwed to the upper shell 7 via connecting screws 10. The lower shell 8 is preferably configured as a casted part and has a greater material thickness than the upper shell 7, which in the present case is configured as a bent sheet metal part. In the embodiment according to FIG. 1, the lower shell 8 directly and completely abuts the rectangular extrusion profile of the module housing 3.

[0048] For the purpose of thermal coupling of the busbars 5 to the busbar housing 6, thermally conductive heat conducting elements 9 are introduced in the form of gap pads between the busbars 5 and the upper shell 7 as well as the lower shell 8. The gap pads 9 do not directly contact the busbars 5, but rather contact an electrical insulation 11, which enclose the actual busbars 5.

[0049] In the present case, the lower shell 8 directly contacts an upper wall of the module housing 3 and both the lower shell 8 and the module housing 3 are made of a material with good thermal conductivity, so that a corresponding thermal coupling is achieved.

[0050] The embodiment shown in FIG. 2 is different from the embodiment shown in FIG. 1. By contrast to the embodiment according to FIG. 1, the lower shell 8 is thermally connected to the module housing 3 of the respective battery module 2 merely locally and, in this respect, not over its entire longitudinal extension. More specifically, the respective battery module housing 3 comprises a connecting portion 13, which projects on a side of the module housing 3 facing the busbar housing 6, in the present case in the Z direction. Preferably, the connecting portion 13 is also used in order to mechanically secure the busbar housing 6 to the module housing 3. Accordingly, the connecting portion 13 serves for both the mechanical and thermal connection of the busbar housing 6 to the module housing 3. For this purpose, the connecting portion 13 can comprise one or more threads for screwing in a connecting screw that passes through the lower shell 8.

[0051] In the embodiment according to FIG. 2, the module housing 3 comprises a terminal opening 16 (not shown in further detail in FIG. 2) for establishing an electrical connection to the respective busbar 5, wherein a terminal element 17 passes through the terminal opening 16, wherein the connecting portion 13 circumferentially encloses the terminal opening 16 and the busbar housing 6 sealingly cooperates with the connecting portion 13. In such an embodiment, the connecting portion 13 is preferably annular in configuration. Such an embodiment is shown schematically in FIGS. 5 and 6, wherein the busbar housing 6 is not shown in FIG. 6 for reasons of clarity.

[0052] Furthermore, in the embodiment according to FIG. 2, it is provided that the busbars 5 in the busbar housing 6 are mechanically held in a bearing structure 17, wherein this bearing structure 17 serves to pre-secure the busbars 5 for ease of assembly. The bearing structure 17 consists of a thermally conductive plastic and is thermally coupled to the lower shell 8 of the busbar housing 6, wherein, in turn, the thermal coupling in the present case takes place via a gap pad 9. The bearing structure 17 comprises a separate retaining portion for each busbar 5, which, in the present case, is filled with heat conducting elements 9 that circumferentially enclose the respective busbar 5.

[0053] In the embodiment according to FIG. 2, a spring element 12 is arranged above the busbars 5, wherein the spring element 12 serves to compensate for manufacturing tolerances and is ensure that no air gap can arise between the busbars 5 and the gap pad 9 as well as the gap pad 9 and the lower shell 8 of the busbar housing 6, in that the spring element 12 presses the busbars 5 in the direction of the lower shell 8.

[0054] In the embodiment shown in FIG. 3, it is provided that a heat sink 14 in the form of a heat sink plate is mounted on an outer side of the module housing 3 facing away from the battery cells 4, wherein this heat sink plate comprises a plurality of cooling ducts that are perfusable with a coolant of the cooling circuit. The busbar housing 6 is mounted on this outer side of the battery module housing 3 comprising the heat sink plate, wherein the lower shell 8 of the busbar housing 6 directly contacts the module housing 3 and not, for example, the heat sink plate 14. Accordingly, the busbar housing 6 and the heat sink 14 of the cooling system are thermally coupled to one another merely indirectly via the housing wall of the module housing 3.

[0055] In the embodiment shown in FIG. 4, the cooling of the battery cells 4 is not carried out via heat sinks 14 mounted on the module housing 3; rather, the internal space of the battery module 2 enclosed by the module housing 3, which receives the battery cells 4, is directly flooded with a dielectric cooling fluid 18 of the cooling circuit. The terminal opening 16 is tightly sealed with a sealing body 15, wherein a connecting element 19, which can be connected to the respective busbar 5, passes through the sealing body 15.

LIST OF REFERENCE NUMERALS

[0056] 1 Battery system

[0057] 2 Battery module

[0058] 3 Module housing

[0059] 4 Battery cell

[0060] 5 Busbar

[0061] 6 Busbar housing

[0062] 7 Upper shell

[0063] 8 Lower shell

[0064] 9 Heat conducting element

[0065] 10 Screw

[0066] 11 Electrical insulation

[0067] 12 Spring element

[0068] 13 Connecting portion

[0069] 14 Heat sink plate

[0070] 15 Sealing body

[0071] 16 Terminal opening

[0072] 17 Bearing structure

[0073] 18 Dielectric cooling fluid

[0074] 19 Terminal element