BATTERY SYSTEM

Abstract

The invention relates to a battery system, in particular for a hybrid drive, comprising a housing and a plurality of battery cells arranged within the housing, said cells being combined to give a cell block, wherein a container having a variable inner volume is arranged between the cell block and at least one housing wall, by means of which container the cell block can be braced relative to the housing, wherein the container is filled with a curable or cured medium.

Claims

1-16. (canceled)

17. A battery system, in particular for a hybrid drive, comprising a housing and a plurality of battery cells arranged within the housing, said battery cells being combined to give a cell block, wherein a container having a variable inner volume is arranged between the cell block and at least one housing wall, by means of which container the cell block can be braced relative to the housing, and wherein the container is filled with a curable or cured medium, characterized in that the housing wall is outwardly deformed, in particular curved, and exerts a bracing force directed into the housing interior onto the cell block via the container, in particular via the pressure bag.

18. The battery system according to claim 17, characterized in that the container is a pressure bag.

19. The battery system according to claim 17, characterized in that the container, in particular the pressure bag, encases four sides, in particular a transverse side, an upper side, a lower side, and an end side, of the cell block.

20. The battery system according to claim 17, characterized in that the container, in particular the pressure bag, has a compressive strength of at least 1.5 bar, in particular at least 2 bar, in particular at least 2.5 bar.

21. The battery system according to claim 17, characterized in that the container, in particular the pressure bag, is formed by two composite films welded to one another at the edge.

22. The battery system according to claim 21, characterized in that the composite films each have a connecting layer, in particular made of polypropylene, and a supporting layer, in particular made of polyamide.

23. The battery system according to claim 17, characterized in that the container, in particular the pressure bag, comprises a supply valve, in particular a pinch valve or a check valve, which can be arranged or is arranged on an end side of the cell block.

24. The battery system according to claim 17, characterized in that the medium is a plastic, in particular a foam, a resin, preferably an epoxy resin, or a gel.

25. The battery system according to claim 17, characterized in that the housing is formed from a steel sheet which has a wall thickness between 2 mm and 5 mm, in particular between 2.5 mm and 4 mm, in particular of 3 mm.

26. A motor vehicle, in particular hybrid vehicle, comprising at least one battery system according to claim 17.

27. A method for assembling a battery system according to claim 17, wherein the following steps are carried out: a) arranging a middle region of the container, in particular the pressure bag, on a transverse side of a cell block; b) folding over the edge regions of the container, in particular the pressure bag, protruding beyond the upper side, and placing one edge region on an upper side of the cell block and one edge region on a lower side of the cell block; c) folding over a front region of the container, in particular the pressure bag, protruding beyond the middle region, and placing the front region against an end side of the cell block; d) arranging the cell block encased by the container, in particular the pressure bag, in the housing; e) filling a curable medium into the container, in particular into the pressure bag, under pressure; and f) curing the medium.

28. The method for assembling a battery system according to claim 27, characterized in that the pressure as the curable medium is filled is between 0.3 bar and 2 bar, in particular between 0.35 bar and 1.5 bar, in particular between 0.4 bar and 1 bar, in particular between 0.45 bar and 0.7 bar, and in particular corresponds to a filling pressure of 0.5 bar.

29. The method for assembling a battery system according to claim 27, characterized in that when filling and/or curing the curable medium, the housing is resiliently deformed at least at the housing walls associated with the edge regions of the container, in particular the pressure bag.

30. The method for producing a pressure bag for a battery system according to claim 17, wherein two composite films are arranged substantially congruently on one another and are welded to one another at their edges, wherein the welding is performed by a laser beam.

31. The method according to claim 30, characterized in that the composite films are connected with weld seams which run at a constant distance from one another.

Description

[0029] The invention will be explained in greater detail hereinafter on the basis of an exemplary embodiment with reference to the accompanying, schematic drawings, in which

[0030] FIG. 1 shows a perspective view of a container, in particular a pressure bag, for the battery system according to the invention;

[0031] FIG. 2 shows a perspective view of a cell block of a battery system according to the invention with the container or pressure bag according to FIG. 1;

[0032] FIG. 3 shows a front view of the cell block according to FIG. 2;

[0033] FIG. 4a shows a cross-sectional view through the housing of a battery system with the cell block according to FIG. 2 prior to filling the curable medium into the pressure bag;

[0034] FIG. 4b shows a cross-sectional view through the housing of a battery system with the cell block according to FIG. 2 after the curable medium has been filled into the pressure bag; and

[0035] FIG. 5 shows a perspective exploded view of a cell block of the battery system according to FIG. 2.

[0036] A container having a variable internal volume and which is preferably formed as a pressure bag 30 is shown by way of example in FIG. 1. The pressure bag 30 is substantially pocket -like or cushion -like and is formed by two composite films, which are welded to one another at their edges. The pressure bag 30 has a geometry which can be divided into a middle region 31, two edge regions 32, and a front region 33. The front region 33 starts here from one of the edge regions 32. The edge regions 32 are separated from one another by the middle region 31. A supply valve 34 is arranged in the front region 33. The supply valve 34 is formed substantially as a check valve and is fixedly connected, for example adhesively bonded or welded, to the pressure bag 30.

[0037] The pressure bag can be filled with a curable medium 35, preferably a plastic. In particular, a foam or a resin, for example epoxy resin, is used as curable medium 35. Here, the pressure bag 30 expands and transfers the filling pressure of the medium 35 in the form of a pre-bracing force to surrounding components. In particular, the pressure bag 30 can exert a pre-bracing force onto a housing 11 of the battery system 10 as a result of the filling pressure of the medium 35.

[0038] The arrangement of the pressure bag 30 in a battery system 10 can be clearly seen in FIG. 2. FIG. 2 shows a perspective view of a cell block 20 of the battery system 10, which also comprises a housing 11 having a housing wall 12. FIG. 2 shows the pressure bag 30, which is arranged around the cell block 20. The pressure bag 30 according to FIG. 2 corresponds to the pressure bag as is illustrated in FIG. 1. In particular, the pressure bag 30 comprises the two edge regions 32, the middle region 31, and the front region 33.

[0039] In the assembled state of the battery system 10, the middle region 31 of the pressure bag 30 extends over a transverse side 14 of the cell block 20.

[0040] The two edge regions 32 extend one over an upper side 15 and one over a lower side 16 of the cell block 20. The front region 33 arranged on one of the edge regions 32 is arranged in a manner lying against the end side 17 of the cell block 20. The pressure bag 30 in essence thus has four sides folded around the cell block 20 and can brace this efficiently in the housing 11.

[0041] As can also be seen in FIG. 2, a plurality of fluid connectors 25 are arranged on the end side 17 of the cell block 20. The fluid connectors 25 are coupled to cooling elements 23 arranged within the cell block 20, said cooling elements being used in order to cool the battery cells 21. The inner design of the cell block 20 will be explained in greater detail in conjunction with FIG. 5.

[0042] FIG. 3 shows the cell block 20 in a front view, wherein the covering of the cell block 20 by the pressure bag 30 can be seen again. The supply valve 34 is arranged on the front region 33 and therefore on the same end side 17 which also carries the fluid connectors 25. All connections and supply valves 34 to be supplied with a fluid are thus all provided on the same side of the cell block 20. The electrical connections of the cell block 20, which is preferably formed as a high-voltage cell block 20, are advantageously arranged on an opposite end side of the cell block 20. An efficient separation between high-voltage region and fluid connector region is thus made possible.

[0043] The cross-sectional view according to FIGS. 4a and 4b explains the principle of the invention, which is implemented in the illustrated exemplary embodiment. Here, FIG. 4a shows the housing 11 with an interior 18, in which a cell block 20 can be arranged and an unfilled pressure bag 30 is placed around the upper side 15, the lower side 16, and the transverse side 14.

[0044] Generally, it is provided in the case of the invention that the pressure bag 30 is filled by a curable medium 35, which cures over time, preferably over a period of a few hours, and thus forms a solid pre-bracing layer. The curable, initially liquid medium 35 is introduced into the pressure bag 30 under a pressure, once the pressure bag 30 has been arranged around the cell block 20 and inserted together with the cell block 20 into the housing 11. The housing 11 deforms due to the pressure within the pressure bag 30. This is clearly illustrated in FIG. 4b. This figure shows the same section as FIG. 4a, wherein the pressure bag is now filled with the curable medium. The housing wall 12 now curves outwardly, in particular on the upper side 15 and the lower side 16.

[0045] The housing 11 has a housing wall 12, which is preferably formed from a steel sheet. The steel sheet expands in the resilient region under the pressure in the pressure bag 30 or curves outwardly. The steel sheet or the housing wall 12 is thus pre-braced in a spring -like manner. This results in a restoring force, which acts as a bracing force into the interior 18 of the housing 11. Here, in particular the relatively broader upper and lower sides 15, 16 of the housing 11 are curved outwardly. The outward curving of the upper and lower sides 15, 16 at the same time causes a stretching force to be exerted onto the transverse side 14, along which the middle region 31 of the pressure bag 30 extends, which stretching force counteracts an outward curving of the transverse side 14. As can be seen in FIG. 4b, the transverse side 14 of the housing 11 therefore is not significantly deformed by the filling of the curable medium.

[0046] Since the two edge regions 32 of the pressure bag 30 of substantially equal volume are arranged along the upper side 15 and the lower side 16, the cell block 20 is prevented from being displaced within the housing as the curable medium 35 is filled into the pressure bag 30. The upper side 15 and the lower side 16 are curved outwardly due to the pressure in the pressure bag 30, wherein the curvature at the apex has a height relative to the originally flat orientation of the upper side 15 or lower side 16 corresponding at least to the wall thickness of the housing wall 12. In other words, the curvature at the apex can have a height which is at least 3 mm. In practice, it has been found that the height of the outward curvature at the apex is approximately 5 mm, so that the total height of the housing after having been filled with the curable medium (FIG. 4b) is approximately 10 mm greater than before it was filled with the curable medium (FIG. 4a).

[0047] For clarification, the structure of a cell block 20 which is integrated into the housing 11 of the battery system 10 is illustrated in FIG. 10. The cell block 20 comprises two battery layers 26, which are assembled from a plurality of battery cells 21. The battery cells 21 are formed as round cells and are mechanically and electrically connected to one another at their poles by contact plates 22. Here, the battery cells 21 are coupled to one another in parallel and series connection. The cell block 20 also has three cooling elements 23 in the form of cooling bags, wherein in each case two cooling elements 23 enclose a battery layer 26 between them. The cooling elements 23 here rest with heat-conductive contact on the contact plates 22. At their longitudinal ends, the cooling elements 23 each comprise two fluid connectors 25, which enable the connection of the cooling elements 23 to a cooling circuit.

[0048] A channel structure 24 is provided within the cooling elements 23 and ensures a uniform flow through the cooling elements 23 and therefore a uniform dissipation of heat. The cooling elements 23, together with the battery cells 21, form the cell block 20. This is encased on four sides by the pressure bag 30 during the assembly of the battery system 10 and is inserted into the housing 11 together with the pressure bag 30. The pressure bag 30 is then filled with the curable medium 25, wherein a filling pressure is set which leads to an outward curving of the housing walls 12. The housing 11 creates a bracing force on account of restoring forces in the housing wall 12, which bracing force acts on the cell block 20 and thus ensures a reliable, heat-conductive contact between the cooling elements 23 and the battery layers 26.

LIST OF REFERENCE SIGNS

[0049] 10 battery system

[0050] 11 housing

[0051] 12 housing wall

[0052] 14 transverse side

[0053] 15 upper side

[0054] 16 lower side

[0055] 17 end side

[0056] 18 interior

[0057] 20 cell block

[0058] 21 battery cell

[0059] 22 contact plate

[0060] 23 cooling element

[0061] 24 channel structure

[0062] 25 fluid connector

[0063] 26 battery layer

[0064] 30 pressure bag

[0065] 31 middle region

[0066] 32 edge region

[0067] 33 front region

[0068] 34 supply valve