Battery system for a motor vehicle

Abstract

Battery system (10) for a motor vehicle, which is arranged in a battery system housing in which at least one cell module (16) with a cell module housing and at least one cooling system (22) for the cell module (16) are further arranged, characterized in that at least one arrangement (38) serving as a gap filler (12) made of a plurality of film rolls (40) is further arranged in the battery system housing, each comprising at least one elastic roll filling (42) and a film covering (44) enclosing the at least one roll filling (42), wherein the film coverings (44) of adjacent film rolls (40) are arranged directly adjacent to each other and thus each form a double-layered crossbar (56).

Description

[0001] The invention relates to a battery system for a motor vehicle according to the preamble of claim 1, in particular to a battery system that is at least partially also intended for powering a motor vehicle. In practice, such battery systems typically have a rated power (continuous power) of at least 2 kW and / or deliver currents of at least 40 A. Such battery systems are often formed—independently or in addition—from several interconnected cell modules. Each cell module weighs at least 5 kg, at least 15 kg, at least 20 kg, at least 25 kg, or at least 30 kg. Such battery systems comprising several such cell modules frequently have a total weight of at least 75 kg, at least 200 kg, at least 600 kg, at least 700 kg, or at least 800 kg.In practice, the dimensions of battery systems according to the invention are regularly such that at least one side of a cell module has a length of at least 10 cm, usually also at least 25 cm, at least 30 cm, at least 40 cm or at least 50 cm. These length specifications often also apply to at least one further dimension, e.g. the width, or even to both further dimensions, i.e. the width and the height. These specifications accordingly also apply to battery systems with at least one such cell module. The battery systems and the cell modules arranged therein are therefore relatively large and heavy compared to energy storage devices from other applications, such as energy storage devices in household appliances.

[0002] WO 2018 / 038 361 A1 discloses a heat dissipation element and a method for its production. The heat dissipation element is formed from a foam padding element encased in a graphite element. During production of the heat dissipation element, two sub-elements are formed from the foam padding element by inserting a thermocompression bonding device from the center from above in a sword-like manner to form a connecting web that separates the sub-elements by thermocompression bonding. The heat dissipation element is intended for a special application in which heat is to be conducted from the end faces of battery cells arranged parallel to one another to a cooling plate.

[0003] DE 10 2013 021 312 A1 discloses a battery comprising a number of individual cells electrically connected in series and / or parallel, a temperature control device, and a number of heat-conducting elements, wherein a heat-conducting element thermally couples at least one individual cell to the temperature control device. The heat-conducting elements are each formed from two halves enclosing a cavity, wherein at least one of the halves forms a full-surface spring element, the surface of which, spaced from the other half, corresponds to at least one flat side of an electrode foil arrangement. A spring force generated by the spring element acts substantially perpendicular to the flat side of the electrode foil arrangement.

[0004] DE 10 2015 113 187 A1 discloses a battery device and a method for producing such a battery device. The battery device is provided for an at least partially electrically powered vehicle having a plurality of battery modules, each with at least one battery cell, and having a receiving device for receiving the battery modules. Each battery module is connected to the receiving device in a contact area for heat conduction, with a heat-conducting element arranged on each battery module, which extends into the contact area and beyond it into a free area of ​​the battery module. At least one elastic deformation element is arranged in the free area for pressing the heat-conducting element against the battery module.As a heat conducting element, a flexible heat conducting mat is described in particular, which can also be combined with a carrier layer and a deformation element in a composite mat.

[0005] DE 10 2016 109 931 A1 discloses a cooling device comprising a cooling plate for an energy storage device to be cooled, which is arranged or can be arranged thereon and is in contact with the cooling plate. A thermally conductive heat-conducting foil and a thermally conductive filler layer are arranged between the energy storage device and the cooling plate.

[0006] US 2014 / 0 008 050 A1 discloses a thermal interlayer arranged as a thermal coupling element between a heat generation unit and a heat dissipation unit. This interlayer comprises a carrier layer referred to as a "liner layer" and a connecting layer referred to as a "connection layer." The carrier layer has perforations. An arrangement consisting of a plurality of film rolls serving as a gap filler is not disclosed.

[0007] KR 10 1 486 369 B1 discloses a heat radiation pad consisting of a cuboid base body and a foil-like covering. The base body is said to be elastic and made of a foam-like material. The heat radiation pad is intended to be used as a single element in a television or monitor. The document does not contain any references to the use of a plurality of such heat radiation pads as a gap-filling arrangement.

[0008] The solutions known from the prior art have the disadvantage that they consist of a large number of individual elements and are therefore complex to assemble and / or are only suitable for a small volume and are therefore only suitable to a limited extent as so-called gap fillers for the variable filling and thermal bridging of free spaces in a battery system for a motor vehicle.

[0009] The invention is based on the object of providing a battery system for a motor vehicle which has a good thermal and at the same time tolerance-compensating connection of the elements arranged therein, which has a low weight and which is simple and practical to handle.

[0010] The object is achieved according to the invention with the features of the independent claim. Further practical embodiments and advantages of the invention are described in conjunction with the dependent claims.

[0011] In a battery system according to the invention for a motor vehicle, which is arranged in a battery system housing, in which at least one cell module with a cell module housing and at least one cooling system for the cell module are also arranged, at least one arrangement serving as a gap filler (gap filler) consisting of a plurality of film rolls is also arranged, each of which comprises at least one elastic roll filling and a film wrapping enveloping the at least one roll filling, wherein the film wrappings of adjacent film rolls are arranged directly adjacent to one another and thus each form a double-layered transverse web that is particularly thermally conductive. In this context, films made of a thermally conductive material are particularly suitable as film wrapping. This is understood to mean films that have a thermal conductivity of at least 10 W / mK, preferably at least 15 W / mK, and more preferably at least 20 W / mK.Film rolls can be produced easily and cost-effectively by simply wrapping them around an elastic roll filling. The elastic roll filling provides an advantageous, tolerance-compensating connection between the elements in the battery system when the corresponding film rolls are arranged in free spaces. This results in easy handling and, at the same time, the requirement for only low compression forces during processing and assembly. Depending on the material, high compression rates can occur in connection with the film rolls.

[0012] Particularly in combination with foil wrappings made of a thermally conductive material, as described above, this offers the advantage of good heat transfer within the battery system. This heat transfer is independent of compression. By selecting a suitable roll filling, a battery system with a low overall weight can be achieved.

[0013] With regard to achieving a battery system with a low overall weight, particular reference is made to the possibility of using an elastic wire mesh, an elastic fiber structure, and / or a foam material for the roller filling. The use of a wire mesh in this context has the further advantage that it also allows for advantageous heat conduction, thus resulting in particularly advantageous heat-conducting properties. However, even if an elastic fiber structure or a foam material is used, a film covering made of a heat-conducting material results in advantageous heat transfer, which in this case occurs primarily via the film covering.

[0014] In a further practical embodiment of a battery system according to the invention, the foil covering comprises a metallic foil or coating, a graphite-containing foil or coating, a carbon fiber-containing foil, and / or a grapheme-containing foil. In this context, foils refer in particular to elements that, due to the effect of gravity and their extremely low flexural rigidity, always tend downward in the direction of gravity when held only on one side.

[0015] In a further practical embodiment of a battery system according to the invention, the film rolls are at least partially a) arranged directly between a wall of a cell module housing and the at least one cooling system, b) directly between the cell module housing a heat transfer plate arranged between the cell module housing and a heat transfer plate arranged between the cell module housing and the at least one cooling system and / or c) arranged in direct contact with an electrical line of a battery system element to be cooled, which is arranged in a housing.

[0016] A battery system element in the above sense is understood, in particular, to be a so-called battery junction box. In the aforementioned arrangement situations according to a), b), and / or c), battery systems according to the invention with film rolls (gap fillers) can be used particularly advantageously, especially when the free spaces change in volume due to temperature. In this respect, the term "housing" refers to any housing used in connection with battery systems, for example, housings for battery junction boxes, cell module housings, and / or larger housings in which one or more battery junction boxes and / or one or more cell module housings are arranged.

[0017] The handling of a battery system according to the invention is further simplified when multiple film rolls are arranged on a flat carrier mat. In this case, flat carrier mats can be pre-produced with a plurality of film rolls and arranged as such in a battery system according to the invention in a single operation.

[0018] In conjunction with such a flat carrier mat, it is particularly preferred if the film rolls are arranged at a distance from one another on one side of the carrier mat. It is also possible to arrange the film rolls at a distance from one another on two opposite sides of the carrier mat. The spaced arrangement of the film rolls has the advantage that sufficient space remains between two film rolls to allow the film rolls to be squeezed widthwise with low compression forces.

[0019] Furthermore, the spaced-apart arrangement of film rolls on one roll side of the carrier mat makes it possible to provide at least two carrier mats on which the film rolls are arranged at a distance from one another such that the carrier mats can each be aligned and arranged with the roll sides relative to one another such that the film rolls of a first carrier mat can at least partially engage in gaps between film rolls of a second carrier mat. In this way, a fully or partially intermeshing arrangement of a first carrier mat and a second carrier mat can be achieved, in which the film rolls from opposite roll sides each engage in gaps between two film rolls of the other carrier mat. In this way, a gap filler arrangement with excellent heat conduction can be achieved in a battery system according to the invention through simple handling.

[0020] In a further practical embodiment of a battery system according to the invention, the film rolls have a round, cuboid, or trapezoidal cross-section. The shape of the corresponding cross-section is preferably selected depending on the elasticity of the elastic roll filling, with round cross-sections being preferred with increasing elasticity, as their shape can adapt well to the gaps to be filled with low compression rates.

[0021] Finally, it should be noted that the film rolls and / or a carrier mat on which the film rolls are arranged can be completely or partially provided with a film-like covering and / or an adhesive coating. This can further improve the thermal conductivity and / or the handling or assembly of film rolls and / or carrier mats in battery systems according to the invention, in particular because an adhesive coating can fix an assembly position selected during assembly relatively in a battery system according to the invention, thus efficiently counteracting relative movements of the film rolls and / or carrier mats, which could occur particularly in the event of driving-condition-related forces and / or vibration excitations.

[0022] In a further practical embodiment of a battery system according to the invention, the foil wrapping has one or more openings or perforations. Such openings are preferably chosen to be small enough to prevent metal chips or other particles from escaping from the interior of the foil wrapping. This is of particular interest in connection with the use of metal fibers as elastic roll filling.

[0023] Further practical embodiments of the invention are described below in conjunction with the drawings. They show: Fig. 1 a schematic representation of a battery system in a first embodiment, Fig. 2 a schematic representation of a battery system in a further embodiment, Fig. 3 a section of a carrier mat with a plurality of film rolls arranged thereon in a perspective view of the roll side from diagonally above, Fig. 4 a representation of a carrier mat in a view from above onto the roll side, Fig. 5 an arrangement of two carrier mats which can be arranged in a meshing manner during assembly, Fig. 6 a battery connection box of a battery system serving as a battery system element with a carrier mat serving as a gap filler with film rolls not shown in an exploded view, Fig. 7 an exemplary representation by the Fig. 6 shown battery connection box with mounted support mat, Fig. 8a-c different arrangements with film rolls with different cross-sectional shapes and Fig. 9 an alternative arrangement of two carrier mats, which can be arranged intermeshing with each other analogous to Fig. 5 during assembly.

[0024] In the Fig. 1 and Fig. 2 shows two different embodiments of battery systems 10 according to the invention, wherein in these and all other figures the same reference numerals are used for identical or at least functionally equivalent elements.

[0025] In the embodiment according to Fig. 1, a carrier mat 14, which is only shown schematically and serves as a gap filler 12, with film rolls not shown, is arranged between a cell module contact surface 18 consisting of one or more cell modules 16 and a cooling system contact surface 20 of a cooling system 22 arranged at a distance.

[0026] At the Fig. In the second embodiment shown in Figure 2, a similarly designed gap filler 12 is provided between a cell module contact surface 18 of one or more cell modules 16 and a first heat-conducting plate contact surface 24 of a heat-conducting plate 26. Furthermore, a further carrier mat 14 serving as a gap filler 12, comprising film rolls (not shown), is provided between a second heat-conducting plate contact surface 28 of the heat-conducting plate 26 and the cooling system contact surface 20 of the cooling system 22.

[0027] Fig. Figure 3 shows an arrangement 38 serving as a gap filler 12, consisting of a plurality of film rolls 40, each comprising an elastic roll filling 42 and a film wrapping 44 enclosing the roll filling 42. In the embodiment shown, the roll filling 42 is formed by a foam material 46. The film rolls 40 are arranged on a flat support mat 48 and firmly connected to the support mat 48.

[0028] As from Fig. As can be seen in Figure 3, film rolls 40 are arranged only on the upper side 50 of the carrier mat 48. The upper side 50 is therefore also referred to as the roll side 52.

[0029] As from Fig. As can also be seen in Figure 3, the film rolls 40 are arranged parallel to one another. Adjacent film rolls 40 are spaced apart by a distance A.

[0030] Fig. Figure 4 shows an entire support mat 48, which in the illustrated embodiment has a length l of approximately 500 mm. Preferred lengths are between 100 mm and 800 mm, particularly preferably between 200 mm and 600 mm.

[0031] The width b of the support mat 48 is approximately 150 mm in the embodiment shown. Preferred widths b are between 50 mm and 400 mm, in particular between 100 mm and 300 mm.

[0032] Fig. Figure 5 shows a schematic representation of an arrangement of two support mats 48, 48', on which, analogous to the Fig. 3 and Fig. 4 film rolls 40, 40' are arranged. In the embodiment shown, the arrangement is achieved by an adhesive coating 32, 32' applied to the respective carrier mat 48, 48'.

[0033] As in Fig. 5, the distance A between two adjacent film rolls 40, 40' is selected to be slightly greater than or equal to the width B of the film rolls 40, 40'. This allows two support mats 48, 48' to be aligned and arranged with their roll sides 52, 52' relative to one another in such a way that the film rolls 40, 40' of a first support mat 48 can engage in gaps between film rolls 40' of a second support mat 48'. This is achieved by moving the support mats 48, 48' in the direction of the arrows 54, 54'.

[0034] In the Fig. 8a, Fig. 8b and Fig. 8c shows three different arrangements with film rolls 40 with different cross-sectional shapes. All arrangements have in common that, between a first component 66 and a second component 68, various transverse webs 56 are formed as a thermal connection between the first component 66 and the second component 68. The transverse webs 56 each consist of a double-layer film sheath 44 made of a thermally conductive material. A particularly good and efficient heat transfer from the first component 66 to the second component 68 can take place via these transverse webs 56. Fig. In the arrangement shown in Fig. 8a, the film rolls 40 have an approximately rectangular cross-sectional shape, in which Fig. 8b shown arrangement has a parallelogram-shaped cross-sectional shape and in the Fig. 8c shown arrangement of crossbars 56 in the form of elevations. Fig. Figure 8c shows an assembly in the installed and pressed state. The pressing during assembly creates the Fig. 8c clearly visible elevations in the area of ​​the crosspieces 56.

[0035] In all cases, the two foil coverings 44 lie directly against one another and thus form a double-layered, particularly thermally conductive transverse web 56.

[0036] An advantage in connection with battery systems in which one or more heat-conducting crosspieces 56 are provided (in particular as in the Fig. 8a-8c), is that the heat conduction is determined by the path of compression, ie by the intensity of the compression of the film rolls 40 (meaning the compression in the direction of the Fig. 8a-8c), is not or only insignificantly influenced, since the length of the crosspieces 56 remains approximately the same regardless of the degree of compression, and regardless of whether there are upheavals as in Fig. 8c and / or whether the webs are deflected laterally as in Fig. 8b. This is a great advantage, especially compared to the use of pastes that are displaced during compression, because the thermal conductivity of the battery system is thus largely independent of the respective manual or mechanical assembly and / or independent of the individual compression properties of specific batches of film rolls 40.

[0037] Fig. Figure 6 shows a so-called battery junction box, which, as battery system element 58, can be part of a battery system 10 in a battery system housing. The battery junction box houses, in particular, electrical power modules, fuse elements, and other electronic components. These also include five electrically conductive elements 60, or 60a, 60b, 60c, 60d, 60e, which can be considered electrical lines 62.

[0038] As in Fig. 6, an arrangement of a plurality of film rolls (not shown), shown only schematically as block 30, can be advantageously used in a battery system 10 according to the invention by arranging the one film roll or several film rolls (not shown individually) in direct contact with one such line 62 or several such electrical lines 62. It is particularly advantageous in this context if at least the areas of the film rolls that come into direct contact with the electrical lines 62 are provided with an electrically insulating coating or an insulating film 64.

[0039] In Fig. In this regard, Figure 7 shows an example of a block 30 having a top side 34 and a bottom side 36, wherein the outer surface of the bottom side 36 is partially provided with an adhesive coating 32 in order to bond the outer surface of the bottom side 36 to an insulating film 64. The block 30 with the film rolls (not shown) can serve as a top closure element of a battery junction box or as a gap filler 12 between a top cover (not shown) of the battery junction box and the electrical lines 62 in order to improve heat transfer to a cooling system (not shown).

[0040] Fig. Figure 9 shows a schematic representation of an alternative arrangement of two support mats 48, 48', on which, analogous to the Fig. 3 and Fig. Four film rolls 40, 40' are arranged. In the embodiment shown, the arrangement is again achieved by an adhesive coating 32, 32' applied to the respective carrier mat 48, 48'. In addition, in this embodiment, an additional film 70 is arranged in a meandering pattern in the region of a carrier mat (here: in the region of the lower carrier mat 48') such that it forms a top-side cover layer.

[0041] The distance A between two adjacent film rolls 40, 40' can be selected to be slightly larger, equal to, or slightly smaller than the width B of the film rolls 40, 40' including the respective thickness of the additional film 70. Here, the distance A is selected to be slightly smaller than the width B, but such that the two carrier mats 48, 48' can each be aligned and arranged with their roll sides 52, 52' relative to one another in such a way that the film rolls 40, 40' of the first carrier mat 48 can be inserted into the gaps between the film rolls 40' of a second carrier mat 48', in particular by pressing. This is done by moving the carrier mats 48, 48' in the direction of the arrows 54, 54'. With the Fig. The arrangement shown in Figure 9 results in particularly good heat transfer, in particular if a film made of a material with good heat conduction is used as the additional film 70.

[0042] The features of the invention disclosed in the present description, the drawings, and the claims may be essential, both individually and in any combination, for the realization of the invention in its various embodiments. The invention may be varied within the scope of the claims and taking into account the knowledge of the person skilled in the art.

[0043] It is particularly noted that the distance A and the width B can be varied on the same support mat 48, 48' and also on different support mats 48, 48'. For example, film rolls 40, 40' with a smaller width B can be arranged on a support mat 48, 48' in a certain area if the heat transfer in the extension direction in the vertical direction, i.e. perpendicular to the length l and perpendicular to the width B, is to be improved in this area. Conversely, by using film rolls with a larger width B in a certain area, the heat transfer can be reduced if this is locally desired. In other words, the local heat transfer can be varied as required by varying the width B and / or the distance A. List of reference symbols 10 Battery system 12 gap fillers 14 support mat 16 cell modules 18 Cell module contact area 20 Cooling system contact surface 22 Cooling system 24 first thermal plate contact surface 26 Heat-conducting plate 28 second thermal plate contact surface 30 blocks (formed from a variety of film rolls) 32, 32' adhesive layer / coating 34 Top 36 bottom 38 Arrangement 40, 40' film rolls 42 roll filling 44 foil wrapping 46 Foam material 48, 48' support mat 50 Top side (of the support mat) 52, 52' roller side 54, 54' Arrow 56 Crossbar 58 Battery system element 60, 60a - 60e electrically conductive element 62 electrical lines 64 Insulation foil 66 first component 68 second component 70 additional foil A Distance (between adjacent film rolls) B Width (of the film rolls) b Width (of the support mats) l Length (of the support mats) F Force arrow Force arrow

Claims

[1] Battery system (10) for a motor vehicle, which is arranged in a battery system housing, in which at least one cell module (16) with a cell module housing and at least one cooling system (22) for the cell module (16) are arranged, characterized by that in the battery system housing there is further arranged at least one arrangement (38) serving as a gap filler (12) comprising a plurality of film rolls (40), each of which comprises at least one elastic roll filling (42) and a film wrapping (44) enveloping the at least one roll filling (42), wherein the film wrappings (44) of adjacent film rolls (40) are arranged directly adjacent to one another and thus each form a double-layer transverse web (56). [2] Battery system (10) according to the preceding claim, characterized by that the roll filling (42) comprises an elastic wire mesh, an elastic fiber structure and / or a foam material (46). [3] Battery system (10) according to one of the preceding claims, characterized by that the foil wrapping (44) comprises a metallic foil or coating, a graphite-containing foil or coating, a carbon fiber-containing foil and / or a grapheme-containing foil. [4] Battery system (10) according to one of the preceding claims, characterized by that the film rolls (40) are at least partially a) are arranged directly between a wall of a cell module housing and the at least one cooling system (22), b) are arranged directly between the cell module housing and a heat conducting plate (26) arranged between the cell module housing and the at least one cooling system (22) and / or c) are arranged in direct contact with an electrical line (62) of a battery system element (58) to be cooled, which electrical line is arranged in a housing. [5] Battery system (10) according to one of the preceding claims, characterized by that several film rolls (40) are arranged on a flat carrier mat (48). [6] Battery system (10) according to the preceding claim, characterized by that the film rolls (40) are arranged at a distance from one another on one roll side (52) of the carrier mat (48). [7] Battery system (10) according to the preceding claim, characterized by that at least two carrier mats (48) are provided, on which the film rolls (40) are arranged at a distance from one another in such a way that the carrier mats (48) can each be aligned and arranged with the roll sides (52) relative to one another in such a way that the film rolls (40) of a first carrier mat (48) can at least partially engage in gaps between film rolls (40') of a second carrier mat (48'). [8] Battery system (10) according to one of the preceding claims, characterized by that the film rolls (40) have a round, cuboid or trapezoidal geometry in cross section. [9] Battery system (10) according to one of the preceding claims, characterized by that the film rolls (40) and / or a carrier mat (48) on which the film rolls (40) are arranged is / are completely or partially provided with a film-like covering (44) and / or an adhesive coating (32). [10] Battery system (10) according to one of the preceding claims, characterized by that the film wrapping (44) has one or more openings or perforations.

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