Battery assembly method for providing a battery arrangement

Abstract

Battery assembly method for providing a battery arrangement (30) with at least one battery module (32), a cooling device (36) for cooling the at least one battery module (32), and a frame (38), wherein the at least one battery module (32) is attached to a first side (36a) of the cooling device (36), and the frame (38) is attached to at least the at least one battery module (32), characterized in that: - to attach the at least one battery module (32) to the first side (36a) of the cooling device (36), the at least one battery module (32) is glued in a module support area (44a) of the first side (36a) of the cooling device (36), without the frame (38) being attached to the cooling device (36); - wherein the cooling device (36) has a separating element (44) providing the first side (36a), which has an edge area (44c) and a transition area (44b).which connects the edge region (44c) with the module support region (44a), wherein the separating element (44) is elastically flexible at least in the transition region (44b), and wherein, after the at least one battery module (32) has been glued on, the frame (38) is placed on the arrangement of the at least one battery module (32) and the cooling device (36) in such a way that at least a part (38b) of the frame (38) rests on the edge region (44c) of the separating element (44).

Description

The invention relates to a battery assembly method for providing a battery arrangement comprising at least one battery module, a cooling device for cooling the at least one battery module and a frame, wherein the at least one battery module is attached to a first side of the cooling device and the frame is attached at least to the at least one battery module. Battery arrangements for motor vehicles, particularly high-voltage batteries, known from the prior art, typically feature a battery housing in which the individual battery modules are accommodated. This battery housing can comprise a base and a frame that essentially provides the housing's side walls, as well as optionally additional partitions to separate the mounting area of ​​the individual battery modules and provide a mounting point for each module. A cooling device for cooling the battery modules is typically attached to the underside of the battery base. This cooling device can also form the base itself. Fig. 1 shows an example of such a prior art battery arrangement 10, comprising a battery module 12, a housing base 14 (which can also serve as a cooling device 16), and a frame 18 to which the housing base 14 is attached by means of fastening elements 20, usually, but not exclusively, screws. To ensure good heat dissipation from the battery module 12 to the cooling device 16, the battery module 12 should fit snugly against the housing base 14. To prevent thermally insulating air gaps between the battery module 12 or its underside and the housing base 14, a gap filler 22, or alternatively a gap pad, is typically inserted between the battery module 12 and the housing base 14. Such gap pads are a type of pouch filled with a gel-like substance.Such a gap filler 22 typically represents a relatively viscous thermal paste. This can, for example, first be applied to the housing base 14, and then the battery module 12 can be inserted and pressed against the housing base 14. This pressing action of the battery module 12 is illustrated in Fig. 1 by arrow 24. Due to this typically very high contact force 24, this gap filler 22 is typically distributed between the battery module 12 and the housing base 14 by being forced outwards, as illustrated by arrows 26. However, this approach presents numerous problems. Firstly, the housing base 14 is typically not flat, as illustrated by height tolerances, such as a slight curvature of the housing base 14, in Fig. 1. This necessitates the described gap filler 22, since otherwise, without this gap filler 22, air bridges would form between the base of the battery module 12, which is typically flat, and the non-flat housing base 14. However, such gap fillers 22 have the disadvantage of being relatively expensive and significantly increasing the weight of the battery assembly 10. Furthermore, their thermal conductivity is not as good as that of metals, for example, so thick gap filler layers lead to a reduction in cooling efficiency. If the gap filler layer is not of uniform thickness, undesirable inhomogeneities in the cooling of the battery module 12 will also result.Another major disadvantage of this arrangement concept is that, without additional tolerance compensation elements, reliable tightening of bolted connections between the battery module 12 and the frame 18 for attaching the battery module 12 to the frame 18 cannot be achieved. Similar fastening problems arise when using other fasteners. Due to the different curvatures of the housing base 14, the mounting flange 12a of the battery module 12 cannot usually be aligned with the corresponding mounting flange 18a of the frame 18, resulting in gaps of varying size. To compensate for these gaps, the aforementioned tolerance compensation elements are used. These elements are positioned between the flanges 12a and 18a and compensate for the tolerances between the two flanges during bolting. These additional elements, however, result in additional costs and weight.A more efficient battery assembly process and a more efficient battery arrangement would therefore be desirable. DE 10 2016 009 972 A1 describes a cell block with a cell stack consisting of multiple individual battery cells, which are stacked with intermediate partitions. To compensate for tolerance-related length deviations in the stacking direction, the partitions are integrated with plate-shaped compensating elements that can be plastically deformed to a specific thickness. The use of compensating elements is unavoidable here to provide tolerance compensation. Furthermore, the patent does not describe how an efficient connection to a cooling system or the attachment of battery modules to the frame can be achieved. WO 2013 / 171205 A1 describes a cooling device for a vehicle battery with at least one cooling line and a separate, elastically designed clamping element to press the cooling line against the outside of the vehicle battery. Pressing the cooling device against the battery's exterior requires very complex clamping mechanisms that demand considerable installation space. Furthermore, DE 10 2013 021 549 A1 describes a high-voltage battery with a cell block comprising a multitude of individual battery cells that are clamped together. Cooling plates are arranged between the individual battery cells. The individual battery cells can be bonded to two opposite sides of a cell holder or the cooling plate. However, a connection to a frame or a cooling device through which a coolant flows is not described here either. Furthermore, DE 10 2012 018 045 A1 describes a battery with a stack of individual battery cells, each having an electrode stack sealed between foils. The individual battery cells are clamped between cell frames and stacked together. Contact tabs of the individual battery cells are connected via an electrically insulating but thermally conductive material, which can be, for example, a potting compound or thermally conductive film, to a cooling device in the form of an actively cooled plate. However, this results in the same disadvantages as described in relation to Fig. 1 and the use of the gap filler. DE 10 2017 208 733 A1 describes a temperature control plate for temperature control of at least two energy storage cells. The temperature control plate is constructed in two layers, consisting of a top plate and at least two base plate segments connected to it, each having a recess. The top plate has die-cut temperature control surfaces that are complementary to the individual energy storage cells and are connected to the top plate via webs. The recesses in the base plate segments are essentially congruent with the corresponding temperature control surfaces in the top plate and, together with the top plate, enclose flow channels for a temperature control fluid. The base plate segments can be connected to each other via elastic connection areas. This enables the temperature control plate to adapt to different height levels of individual energy storage cells. DE 10 2018 216 113 A1 relates to a method for arranging at least one battery module in at least one part of a battery housing with a cooling device arranged on one side of the part of the battery housing and having a predetermined module mounting area. A heat-conducting component is placed on the cooling device at least in the predetermined module mounting area, and the at least one battery module is inserted into the module mounting area and pressed against the heat-conducting component in a pressing direction extending towards the cooling device. Before pressing, a counter-support device is arranged on the cooling device, which supports the cooling device against the pressing direction when the at least one battery module is pressed against the predetermined module mounting area. The object of the present invention is therefore to provide a battery mounting method which enables the simplest and most efficient connection of a battery module to a cooling device and a simplified attachment of the battery module to a frame. This problem is solved by a battery assembly method with the features according to claim 1. Advantageous embodiments of the invention are the subject of the dependent claims, the description, and the figures. In a battery assembly method according to the invention for providing a battery arrangement comprising at least one battery module, a cooling device for cooling the at least one battery module, and a frame, the at least one battery module is attached to a first side of the cooling device, and the frame is attached to at least the at least one battery module. To attach the at least one battery module to the first side of the cooling device, the at least one battery module is glued to a module support area of ​​the first side of the cooling device, without the frame being attached to the cooling device. Furthermore, the cooling device has a separating element providing the first side, which has an edge area and a transition area that connects the edge area to the module support area, wherein the separating element is elastically flexible at least in the transition area.After the at least one battery module has been glued in place, the frame is placed on the arrangement of the at least one battery module and the cooling device in such a way that at least part of the frame rests on the edge area of ​​the separating element. By elastically and flexibly connecting the edge area on which the frame section rests to the module support area in which the battery module is arranged, a tolerance compensation can advantageously be provided. This allows the battery module to be attached to the frame without the need for any compensating elements, and this attachment can be implemented, for example, as a screw connection. Thanks to the advantageously provided tolerance compensation, even tight screw connections can now be achieved without any intermediate elements or compensating elements. Although the attachment of the frame to the at least one battery module is preferably achieved by screw connections, this attachment can additionally or alternatively be achieved by any other fastening method.Fastening means are achieved, for example, by welding, in particular thermal welding, laser welding, spot welding, etc., and / or by means of punch-rivet elements and / or clamps or clamping elements or similar. However, even with fastening using such means or fastening options, the invention offers the same advantages of a particularly stable connection without the need for additional compensating elements. A particularly significant advantage of the invention is that the battery module is glued to the first side of the cooling device without the frame being attached to the cooling device. The frame can then be attached to the cooling device, either only afterward or not at all.This is based on the understanding that even if the first side of the cooling unit, particularly in the battery module support area, has unevenness or is warped, such warping or unevenness can be easily compensated for by placing the battery module onto this first side of the cooling unit. Typically, the weight of the battery module itself is sufficient to flatten a slightly deformed cooling unit. Alternatively, a slight downward pressure can be applied to the battery module in the direction of the cooling unit when placing it on the unit.However, because the cooling device is not attached to the frame, it can now be smoothed out. This is because, when the battery module is placed on the frame, the cooling device can expand in a direction perpendicular to the direction of placement. This is because, advantageously, the cooling device is no longer fixed in position by being attached to the frame when the at least one battery module is placed on the frame. If the cooling device, which could be, for example, a thin cooling plate or base, were attached to a frame at two opposite ends, a slight inward or outward curvature could not be compensated for by applying pressure, since the ends of the cooling device would be fixed and therefore could not move in any direction.In contrast, the invention advantageously makes it possible to completely dispense with the gap filler described above, and the battery module can, for example, be connected to the cooling device solely via a thermally conductive adhesive. Such adhesive layers can be significantly thinner than typical gap filler layers, and, moreover, such an adhesive layer can be applied very homogeneously due to the flatness of the cooling device when the module is placed on the module support area, as well as the flatness of the module base. This significantly increases cooling efficiency, since the thermal conductivity of the heat path from the battery module to the cooling device is considerably enhanced and also much more homogeneous across the entire underside of the battery module.Overall, this battery mounting method offers numerous advantages over previous methods, as the elimination of the gap filler and the possibility of eliminating numerous compensating elements for hard screw connections between the battery modules and the frame significantly reduces weight and costs, while simultaneously increasing cooling efficiency considerably. The frame can be a self-contained unit and supplied separately. The battery assembly provided by the battery mounting method can then be installed on the vehicle, for example, in an underbody area. For this purpose, the battery assembly can be attached to the vehicle, for example, via the frame. Before or after this, the battery assembly can be fitted with a cover on its upper side (i.e., on the side of the frame facing away from the separating element), which can be placed and attached to the frame, and / or with an underride guard on its underside, which can be attached to the cooling system, in particular the separating element, and / or to the frame. Alternatively, the frame can also be a non-independent unit, but rather a part of a motor vehicle. Preferably, the frame is provided by a part of the vehicle structure of the vehicle's underbody. For example, at least parts of the frame can simultaneously form parts of a transverse and / or longitudinal member structure of the vehicle. This has the significant advantage of saving additional weight and components. Here, too, the battery assembly can be provided on its upper side, i.e., on a side of the frame or the vehicle structure of the underbody facing away from the separating element, with a cover that can be placed and attached to the frame, and / or on its underside with an underride guard that can be arranged on the underside of the cooling unit, in particular the separating element, and / or also on the frame.In this context in particular, but also in general, the term "placing the frame onto the arrangement of the at least one battery module and the cooling device" can also be understood to mean that the frame is or remains stationary during this placement, i.e., it is not moved, and, for example, the arrangement of the at least one battery module and the cooling device is moved from below towards the frame and positioned on it in such a way that at least part of the frame rests on the edge area of ​​the separating element. The at least one battery module can generally comprise at least one battery cell, such as a lithium-ion cell. Preferably, however, the at least one battery module comprises several individual battery cells, which can be arranged in a battery stack. These individual battery cells are preferably prismatic cells. In principle, however, the battery cells can also be designed as pouch cells. The cooling device for cooling the at least one battery module is preferably designed as an active cooling system and accordingly uses a cooling medium or coolant, which can generally be gaseous and / or liquid, to remove heat from the at least one battery module. Preferably, the cooling device has cooling channels through which a coolant flows. The cooling device can be designed as a cooling base, such that the aforementioned separating element simultaneously provides a side wall of at least one cooling channel. In other words, the coolant is in direct contact with at least one area of ​​the separating element.The cooling system can also include a separate cooling unit, which, for example, can be a cooling plate with cooling channels. This cooling plate, in turn, can be made of thin sheets with integrated cooling channels. This cooling unit is then attached to the partition element, for example, by gluing it to the partition, thus providing the cooling system. In both cases, the partition element provides separation between the high-voltage compartment and the wet compartment, simplifying the overall design as additional insulation and safety measures are unnecessary. As described above, the separating element is designed to be elastically flexible, at least in the transition region. This preferably means that the separating element is bendable in this transition region when a corresponding force is applied, for example, to its edge, and that when bent, its elastic flexibility provides a corresponding restoring force that opposes the deformation force causing the bending. This elastic flexibility preferably does not imply elastic compressibility of the separating element, but rather simply means that the separating element is designed in the transition region to be bendable while generating a corresponding restoring force.The separating element does not necessarily have to be elastically flexible only in the transition area, but can also be elastically flexible in the edge area and overall, for example also in the module support area, although this elastic flexibility in the module support area is not necessary. It is particularly advantageous if the separating element is provided as a separating sheet, that is, as a sheet with a maximum thickness of one millimeter, for example, with a thickness in the range between 0.8 and 1.0 millimeters. By manufacturing it as such a thin sheet, for example from aluminum or another metal or alloy, the elastic flexibility of the separating element described above can be provided in a particularly simple and cost-effective manner, and in this case, throughout the entire assembly, not just in the transition area. This allows for a particularly simple and cost-effective way to compensate for tolerances between the mounted frame and the at least one battery module, enabling the use of tight bolted connections between the battery module and the frame.The separating element can also be designed to be elastically flexible in the transition area in other ways, for example, by having an elastically flexible plastic in the transition area, or similar. The frame mentioned above can provide the remaining part of a battery housing. In particular, this frame can be designed as described above and provide the side walls of the battery housing as well as optional additional partitions between the mounting areas of several battery modules for securing these battery modules. Furthermore, the battery arrangement preferably also includes several battery modules, so that the battery arrangement can, for example, provide a high-voltage battery for a motor vehicle, especially an electric vehicle. Therefore, a further advantageous embodiment of the invention involves adhering several battery modules to the module support area of ​​the first side of the cooling device. Before being arranged in this area, the battery modules are fixed in their relative positions, and the fixed arrangement of the battery modules is then placed and adhered to the first side of the cooling device. This advantageously makes battery assembly significantly more efficient, as it eliminates the need to individually position and secure each battery module. For example, before placing the battery modules onto the separating element, all battery modules of the battery arrangement can first be fixed in their relative positions. This battery arrangement can then be gripped as a whole, for example, by a suitable gripping and holding device, and placed onto the separating element or an adhesive located on the separating element.The modules can be connected to each other much more easily if they are not yet placed on the separating element with the adhesive applied to it. This results in a significant time saving during battery assembly. Furthermore, designated module support areas can be provided on the separating element for each individual battery module. Furthermore, it is conceivable that all battery modules of the high-voltage battery are mounted and bonded onto a common separating element, which is therefore formed in one piece. However, it is also conceivable that several individual assemblies, each consisting of one or more battery modules and an associated cooling unit, are first provided as described above, and then the frame is mounted onto these multiple assemblies and attached to the respective battery modules. For example, a first row of battery modules, consisting of several modules that have been pre-fixed to each other, can first be mounted and bonded onto an associated cooling unit, in particular its separating element. Then, a second such row of battery modules can be mounted and bonded onto another cooling unit, in particular its separating element, and so on.The module rows, complete with their associated cooling units, can then be positioned relative to each other in the desired arrangement. The frame can then be placed on these arrangements and bolted to the battery modules. This advantageously provides numerous flexible options for battery mounting, which can be selected according to requirements or situation. In a further advantageous embodiment of the invention, after the frame has been mounted, the frame is screwed to the at least one battery module, so that in the screwed-together state of the frame and the at least one battery module, a part of the frame, which is integrally formed with the frame, is in direct contact with a part of the at least one battery module. This part of the battery module and this part of the frame can, for example, again represent corresponding flanges, as described above.These flanges, or more generally these two parts of the battery module and the corresponding frame, can now advantageously be brought directly onto the support by elastically bending the transition area of ​​the separating element, since any tolerances or height differences between these two parts to be bolted together can be advantageously compensated for by the separating element or by its elastically flexible design in the edge or transition area. Without additional aids such as additional compensating elements, particularly stable and robust bolted connections can thus be achieved. Each battery module can, for example, be bolted to the frame at four bolting points. Attaching the frame to the cooling unit, particularly to the partition, is generally unnecessary, as the frame is attached to the battery modules, and the battery modules are in turn firmly attached to the cooling unit via the adhesive bonds described. Nevertheless, to increase the stability of the assembly, the frame can still be attached directly to the partition. However, it is preferable that, after the frame is in place, it is screwed to the partition only at its edge. Such edge-only fastening is perfectly sufficient, since, as described, the battery modules are already firmly attached to the partition via the adhesive bond and are also firmly connected to the frame via the screw connections described. This advantageously eliminates the need for additional fasteners.A particularly significant advantage of attaching the frame to the partition only at its edge lies in the fact that this further increases cooling efficiency. If, for example, screw connections between the partition or cooling unit and the frame are also implemented in the areas between the individual battery modules, the screws of these connections would also be cooled by the cooling unit, resulting in a significant loss of cooling capacity that cannot be used to cool the battery modules themselves. By attaching the frame only at the edge of the partition, these cooling losses can be advantageously minimized, and the cooling of the battery modules can be made even more efficient. In a further advantageous embodiment of the invention, the frame has struts which, in the state of the frame being placed on the arrangement of the at least one battery module and the cooling device, extend perpendicularly at least to the module support area of ​​the separating element, wherein the struts have a widening on a side facing away from the separating element, which forms a projection which extends in a direction perpendicular to the direction of travel of the struts over at least a part of the at least one battery module and which has at least one screw hole, wherein, for screwing the frame to the at least one battery module, a screw is screwed through the screw hole and at least partially into or through the part of the battery module.In other words, the described struts can have a T-shaped cross-section and thus, at least partially, project beyond a portion of a battery module, particularly an edge area of ​​the module, which can, for example, simultaneously serve as a mounting flange. This allows for a particularly simple bolting connection of the frame to the respective battery modules. In particular, such a connection can be implemented in a very space-saving manner. This is possible because at least one battery module is already mounted on the cooling unit or the separating element when the frame is placed onto this assembly from above.If the frame had first been attached to the cooling device or the separating element and the modules were subsequently inserted, as is common practice in the prior art, it would not be possible to implement the described struts with such overhangs, since the modules could then no longer be inserted. In a further advantageous embodiment of the invention, several screw holes are arranged in the overhang at a specific distance from one another in a longitudinal direction. The screw holes used to bolt the frame to the battery modules are selected from these multiple screw holes depending on the respective module sizes of the battery modules and / or their arrangement relative to one another. By providing variations in the screw hole pattern, a flexible module grid can be provided, allowing for flexible, and in particular different, module sizes. Specifically, the battery arrangement can also include battery modules of different module sizes. This advantageously allows battery modules with different properties to be used simultaneously in a single battery. These battery modules can also be arranged very flexibly relative to one another.This advantageously allows for significantly more flexibility in the provision of a high-voltage battery. A particularly significant advantage of the invention and its embodiments is that the described battery mounting method allows the use of considerably larger battery modules than previously possible. If, as is common practice in the prior art, a battery module is placed on a housing base already connected to the frame, and especially on a gap filler located thereon, the battery module must be pressed as firmly as possible against the housing base to ensure that the gap filler is distributed as evenly as possible between the module base and the housing base. At the same time, it must be ensured during this pressing process that the battery module itself is not damaged. Such pressing without damaging the battery module becomes increasingly difficult the larger the battery module is, which is why typically not particularly large module sizes can be used with this type of mounting method.However, since the invention makes it possible to place modules onto the separating element without having to apply high contact forces to the module, and in some cases even without having to apply any additional contact forces to the module at all, significantly larger battery modules can also be used. This, in turn, increases manufacturing and assembly efficiency and simultaneously enhances the flexibility of application possibilities. In a further advantageous embodiment of the invention, the separating element is unevenly designed, such that the first side provided by the separating element is raised in the central module support area for the at least one battery module compared to an edge area of ​​this module support area. A raised area is understood to mean a curvature or change in level in the direction of the battery module to be arranged on the support area or of the battery module already arranged on the support area. The reason for this is that the battery module is preferably designed to comprise several individual battery cells, which in turn are enclosed by an angle iron frame. However, the battery modules can also be enclosed by other enclosing elements.In this design, such a frame or surround element encircles the battery module, particularly at its edges. This typically results in the battery module being taller at its edges than in its center, or at least the underside of the battery module facing the cooling system being raised in the center compared to its edges. Because the separating element is geometrically designed to match this, being raised in the center of the support area compared to its edges, its shape is optimally adapted to the shape of the underside of the battery module. This, in turn, allows for uniform gap widths between the separating element and the battery module, and consequently, uniform heat dissipation.Furthermore, increasing the height of the separating element in the central support area significantly reduces the gap between the battery module and the separating element in this central support area, as well as in the central module base area, thereby further increasing cooling efficiency. Such a partial increase in the height of the separating plate in the central support area, or in the respective central support areas assigned to the battery modules, can be easily achieved, for example, by continuously embossing the separating element. On the other hand, if the battery module is designed with a completely flat module base without any elevation in the central module base area, then it is correspondingly preferred that the separating element is also designed to be flat. In a further advantageous embodiment of the invention, a spacer element with a maximum thickness of one millimeter is arranged between the edge region of a module base of the at least one battery module and the separating element. The purpose of this is to ensure that, during servicing or after the service life of a high-voltage battery, the individual battery modules can be removed from the battery housing as easily as possible. Ideally, the separation of the battery module from the cooling unit, and in particular from the separating element, should also be as simple as possible. This can be achieved, for example, using a standard wire saw designed to cut through materials such as plastic, metal, glass, ceramic, and so on.A battery module can then be bent over at the base by such a wire saw, or rather by the wire of such a wire saw, and the wire then passed between the module base and the separating element, thus cutting the adhesive bond between the module base and the separating element. To simplify the insertion of such a wire, especially at the edge of the module base, it is particularly advantageous to provide a spacer between the module base and the separating element in this area. A spacer with a thickness of no more than one millimeter is perfectly sufficient, as wire saws with wires with a diameter of less than one millimeter are also available.Such a spacer element does not noticeably reduce cooling efficiency, while simultaneously enabling particularly easy battery recycling and the removal of modules for repairs. This spacer element can be made of virtually any material, as typical wire saws are designed to cut numerous different materials, including very hard ones like metal. Accordingly, the material of the spacer element can be chosen almost arbitrarily and can, for example, also have good thermal conductivity, such as metal or metal particles. Since the spacer element is already very thin and can also have a very small diameter, a material that is particularly easy to cut, such as a soft plastic or similar, can also be selected.This design is particularly advantageous if the battery module has a module base which, after the at least one battery module is arranged on the cooling unit, faces the cooling unit and is uneven, such that the module base is raised in a central area compared to an edge area. As described above, such a raised area can be caused by the geometry and arrangement of edging elements for enclosing the battery cells. In such a case, very narrow gaps result between the module base at the edge and the separating element, making the arrangement of a spacer element particularly advantageous here. A battery arrangement produced by means of a method according to the invention or one of its embodiments comprises at least one battery module, a cooling device for cooling the battery module and a frame, wherein the at least one battery module is attached to a first side of the cooling device and the frame is attached at least to the at least one battery module.The at least one battery module is attached to the first side of the cooling device by means of an adhesive layer between the at least one battery module and a module support area of ​​the first side of the cooling device, wherein the cooling device has a separating element providing the first side, which has an edge area and a transition area that connects the edge area with the module support area, wherein the separating element is elastically flexible at least in the transition area, and wherein the frame is placed on the arrangement of the at least one battery module and the cooling device in such a way that at least a part of the frame rests on the edge area of ​​the separating element. A motor vehicle may comprise a battery assembly produced by means of a battery assembly method according to the invention. The motor vehicle is preferably designed as a motor vehicle, in particular as a passenger car or truck, or as a passenger bus or motorcycle. The invention also includes combinations of the features of the described embodiments. The following are described exemplary embodiments of the invention. Figure 1 shows a schematic representation of a battery arrangement according to the prior art; Figure 2 shows a schematic representation of a cooling device and a battery module mounted thereon for a battery arrangement according to an exemplary embodiment of the invention; Figure 3 shows a schematic representation of the arrangement consisting of a cooling device and battery module from Figure 2, now with a frame mounted on this arrangement according to an exemplary embodiment of the invention; Figure 4 shows a flowchart illustrating a battery assembly method according to an exemplary embodiment of the invention; Figure 5 shows a schematic cross-sectional representation of a battery arrangement to illustrate the tolerance compensation provided by the flexible areas of the separating element, according to an exemplary embodiment of the invention; Figure 6 shows...6 a schematic and perspective view of a battery arrangement to illustrate the fastening options between the frame and a respective battery module according to an embodiment of the invention; Fig. 7 a schematic exploded view of a battery arrangement with battery modules of different sizes according to an embodiment of the invention; and Fig. 8 a schematic cross-sectional view of a battery arrangement with a separating element of the cooling device raised in the central module support area and with spacer elements in the edge area of ​​the module support area between the separating element and the battery module to provide a simple separation option between the battery module and the separating element, according to an embodiment of the invention. The exemplary embodiments described below are preferred embodiments of the invention. In these exemplary embodiments, the described components each represent individual features of the invention, which can be considered independently of one another and each further develops the invention independently. Therefore, the disclosure is intended to include combinations of features of the embodiments other than those shown. Furthermore, the described embodiments can also be supplemented by further features of the invention already described. In the figures, identical reference symbols denote functionally equivalent elements. Fig. 2 shows a schematic representation of part of a battery arrangement 30, in particular an arrangement consisting of a battery module 32 and a cooling device 36, which, for example, simultaneously provides a housing base 34 of a battery housing. Fig. 3 shows the arrangement from Fig. 1 accordingly, with a frame 38 now attached to this arrangement, which can also provide part of the battery housing, in particular the side walls of such a battery housing, as well as optional further partitions between battery modules 32. According to the invention, it is advantageously provided that the battery module 32, and in particular several battery modules 32 simultaneously, are placed on the cooling device 36 and adhered to it by means of an adhesive layer 35 before the frame 38 is attached. The frame 38 is attached to the battery modules 32, as described in more detail below, whereby fastening the frame 38 to the cooling device 36 is merely optional. Thus, because the frame 38 is not rigidly connected to the cooling device 36 when the battery module 32 is placed and adhered to it, any unevenness of the cooling device 36 prior to the placement of the battery module 32 can be compensated for by placing the battery module 32 and possibly pressing it down slightly, as illustrated by arrow 39.Such a curvature of the cooling device 36 before the battery module 32 is placed on it is schematically illustrated in Fig. 2 by the dashed lines labeled 34' and 36'. Furthermore, when the battery module 32 is placed on it, the cooling device 36 is preferably arranged on a flat support 40, which supports the cooling device 36 from below. This advantageously allows the cooling device 36 to be smoothed out when the battery module 32 is placed on it without requiring much force, since the cooling device 36 can expand laterally, as illustrated by arrows 42. This expansion is only possible because the cooling device 36 is not fixed in its position by being attached to the frame 38 at the time the battery module 32 is placed on it, thus preventing the z-tolerance of the cooling base from being frozen.Because this results in a particularly flat cooling base or surface of the cooling device 36, the gap filler 22 described above can be completely dispensed with, or its required quantity can be significantly reduced, as can its viscosity. This enables considerably simpler battery assembly in a much more cost-effective and weight-saving manner. In particular, for example, only the described adhesive layer 35, which is preferably also thermally conductive, at least with a thermal conductivity equivalent to that of known gap fillers, can be used to attach the respective battery module 32 to the cooling device 36. There are several possibilities for the design of the cooling device 36, which are described in more detail below. In particular, the cooling device 36 always has a separating element 44 (see, for example, Fig. 4), which provides the side 36a facing the battery module 32. This separating element 44, and correspondingly this first side 36a of the cooling device 36, can be subdivided into several areas. A first area 44a of the separating element 44 represents a module support area onto which the battery module 32 is placed, or in which the battery module 32 is arranged, or in which its base is adhered via the adhesive layer 35. A second area represents a transition area 44b to an edge area 44c.The frame 38 of the battery assembly 30 is placed onto the assembly consisting of the battery module 32 and the cooling device 36 in such a way that at least a part of the frame 38, in particular the part of the frame 38 that also provides the outer walls of the battery housing, is brought into contact with the edge region 44c of the separating element 44 or is placed directly onto it. At least the transition region 44b of the separating element 44 is elastically flexible. This can be easily achieved, for example, by designing the separating element 44 as a thin separating sheet, for example, with a thickness of less than 1 millimeter. This advantageously provides tolerance compensation in the z-direction shown.This advantageously allows a part 38a of the frame 38, which is to be screwed to a part 32a of the battery module 32, to be directly supported against this part 32a of the battery module 32. These two parts 38a and 32a of the frame 38 and the battery module 32 can, in turn, be provided by suitable screw flanges. This advantageously allows for rigid screw connections and significantly simplifies battery assembly without the need for any additional spacers between these flanges 38a and 32a. These individual assembly steps are shown in detail in Fig. 4. Fig. 4 shows a flowchart illustrating a battery assembly method according to an embodiment of the invention. In step S10, a cooling device 36 is provided, in particular again on a flat workpiece carrier 40. The cooling device 36 can be provided in various ways, for example as a cooling floor, as is also illustrated here by way of example in steps S10, S12 and S14. The cooling device 36 has a separating element 44, which simultaneously provides the first side 36a of the cooling device 36, which faces the battery module 32 arranged thereon. In this example of the cooling device 36, this separating element 44 also forms a wall of at least one cooling channel 36d of the cooling device 36 through which a coolant flows.On the side opposite this separating element 44, the at least one cooling channel 36d can be bounded by a further wall 36b. Alternatively, the cooling device 36 can also be configured, in particular as illustrated by way of example in steps S16 and S18, such that the cooling device 36 has a separate cooling unit 36c. This cooling unit 36c can in turn be configured as a cooling plate with cooling channels running through it, which are not explicitly shown here. This cooling unit 36c can then be bonded to the underside of the separating element 44 via an adhesive layer 35.If a cooling device 36 designed in this way is used for the battery arrangement 30, the assembly step S10 described here can be preceded by further assembly steps in which the cooling unit 36c is first provided, an adhesive layer is applied to it, and the separating element 44 is then placed and glued onto the adhesive layer, thus providing the cooling device 36, which is now the starting point for the further process steps, in particular the further process step S12. In this further process step S12, an adhesive layer 35 is applied to the upper side of the cooling device 36, that is, to the first side 36a described above, in particular in a module support area 44a (see Fig. 3) of the separating element 44. In the next step S14, an arrangement of battery modules 32 is placed onto this adhesive layer 35.It is preferred that the individual battery modules 32 are not placed individually onto the cooling device 36, but are first fixed in their arrangement to one another, for example by suitable screws, and then placed as a whole onto the cooling device 36, in particular onto the adhesive layer 35 located thereon, and thus bonded to the cooling device 36. Optionally, a pressing or calibration device 46 can also be used, by means of which the battery modules 32 can be lightly pressed onto the cooling device 36, for example until the adhesive of the adhesive layer 35 has cured. This pressing or calibration device 46 can then be removed again, in particular before the frame 38 is placed onto the arrangement of battery modules 32 and cooling device 36 in step S16.The frame 38 can be mounted using a suitable workpiece carrier 48, for example in the joining direction 50 shown here. In this example, the frame 38 provides, on the one hand, the outer walls 38b of a battery housing, and on the other hand, partitions 38c arranged between battery modules 32. Both these partitions 38c and the outer walls 38b of the frame 38 have suitable screw flanges 38a, which are provided with suitable screw holes for screwing the frame 38 to the battery modules 32 in a subsequent step S18, in particular using screws 52, which are shown schematically here. The workpiece carrier 48 can be removed beforehand or retained during the screwing process to more easily hold the frame 38 in its position relative to the battery module 32. For the sake of clarity, however, this workpiece carrier 48 is not shown in step S18.The frame 38 is preferably bolted to the battery modules 32 from above, meaning that the respective bolts 52 are inserted through the flanges 38a shown into corresponding parts, for example, flanges 32a of the battery modules 32, in a direction from the battery modules 32 to the cooling device 16 and bolted in place. Bolting from below, i.e., through the cooling device 16, would also be conceivable, but is more complex and therefore less preferred. The frame 38, in particular the side walls 38b of the frame 38, rests on the edge region 44c of the separating element 44, which is elastically and flexibly connected to the module support area 44a against which the battery module 32 rests. This advantageously allows the described tolerance compensation in the z-direction to be achieved, enabling tight screw connections between the frame 38 and the battery modules 32 without any complex additional elements. This tolerance compensation is illustrated again by way of example in Fig. 5. Fig. 5 shows a schematic cross-sectional view of a battery arrangement 30 according to a further embodiment of the invention. In particular, the battery arrangement 30, as schematically depicted in Fig. 5, can represent the result of the method described with reference to Fig. 4. Specifically, the respective areas 44a, 44b, and 44c of the separating element 44 are shown enlarged to illustrate the principle of this tolerance compensation in a somewhat exaggerated representation. As described, the separating element has a central module support area 44a on which the respective battery modules 32 rest. A separate module support area 44a can also be provided for each individual battery module 32. A transition area 44b adjoins these module support areas 44a towards the edge of the separating element 44, connecting a module support area 44a with the edge area 44c of the separating element 44.As described, the side wall 38b of the frame 38 is arranged in the edge region. Since at least the transition area 44b of the separating element 44 is flexible, tolerance compensation can advantageously be provided when placing the frame 38 and attaching it to the battery modules 32. This is illustrated by the bends of the separating element 44 in this transition area 44b in Fig. 5. Here, too, the separating element 44 can again be designed as a thin sheet metal, which enables such tolerance compensation in a particularly simple and cost-effective manner, since such a sheet metal inherently possesses such elastically flexible properties. In this example, the cooling device 36 also has a separate cooling unit 36c, which is glued to the underside of the separating element 44. The cooling unit 36c can also be provided as a cooling base, as shown, for example, in Fig.4 , especially step S10 is described. For the sake of clarity, the adhesive layer 35 is not explicitly shown in Fig. 5, but it is still located between the respective battery modules 32 and the top of the separating element 44. Fig. 6 shows a schematic and perspective view of a battery arrangement 30 according to a further embodiment of the invention. This battery arrangement 30 also comprises, as described, several battery modules 32, of which only two are shown here by way of example. Furthermore, the battery arrangement 30 again comprises a frame 38 and a cooling device 36. In particular, the battery arrangement 30 can be configured as described above. In this illustration, the geometries of the partitions 38c are particularly easy to see. These partitions are preferably T-shaped in cross-section and thus preferably have a widening 38a in the z-direction shown, which also provides the screw flanges 38a. Screw holes 54 are arranged in these widened areas 38a, through which the screws 52 (see Fig. 4) can be passed to fasten the frame 38 to the respective battery modules 32. For clarity, only some of the screw holes 54 are labeled. This geometry allows for a particularly space-efficient arrangement between the frame 38 and the respective battery modules 32, as well as a particularly simple screw connection.A particularly significant advantage lies in the fact that provisions can be made in the hole pattern to allow for a flexible module grid. For example, numerous screw holes 54 can be provided along the separating web 38c provided by the frame 38 in the flange area 38a. Not all of these need to be used for screwing or fastening the frame 38 to a respective battery module 32; only some can be selected and used, for example, depending on the arrangement of the battery modules 32 relative to each other, and also depending on the size of the respective battery module 32. This advantageously allows the use of battery modules 32 of different sizes without having to make any additional modifications to the battery housing, especially to the frame 38, apart from the provided holes 54. This is shown in Fig.7 is illustrated in more detail. Fig. 7 shows an exploded view of the battery arrangement 30 according to an embodiment of the invention. In particular, Fig. 7 shows the described frame 38 with its outer walls 38b and the respective partitions 38c. The arrangement comprising the cooling device 36 with battery modules 32 bonded to it is also shown. These battery modules 32 can be of different sizes, as also shown in Fig. 7. In particular, battery modules 32 in four different sizes are shown. The sizes of the battery modules 32 can differ, for example, in their length, while the width and height, i.e., the dimensions in the z-direction, are preferably the same.In this example, the shortest battery module is designated 32C, a slightly longer one 32A, a battery module 32B is even longer than the one designated 32A, and the largest or longest battery module 32 is designated 32D. The hole pattern in the frame 38, as described in Fig. 6, thus advantageously allows for an arrangement of battery modules 32 of different sizes. Fig. 8 shows a schematic cross-sectional view of a battery arrangement 30 according to a further embodiment of the invention. Here again, an exemplary battery module 32 is shown, as well as the cooling device 36, which in turn comprises the separating element 44 and a separately designed cooling unit 36c with cooling channels 36d arranged thereon. The cooling device 36, in particular the separating element 44, is again bonded to the underside of the battery module 32 by the adhesive layer 35. The battery module 32 comprises several individual battery cells, which are not shown separately in this example. These are enclosed by a frame 56, such as an angle iron frame for enclosing the individual cells. This frame 56 extends in an edge region of the battery module 32 also below the battery cells.This causes the base of the battery module 32 to be raised in a central area 60 relative to an edge area 58 in the z-direction. To simultaneously minimize the gap between the module base of the battery module 32, particularly in the central area 60, and the separating element 44, the shape of the separating element 44 can be adapted to the geometry of the module base. Accordingly, the separating element 44 preferably also has a raised area in a central region corresponding to the central region 60 of the battery module 32, relative to an edge area of ​​the module support area 44a of the separating element 44, with this edge area in turn corresponding to the edge area 58 of the battery module 32. Such a raised area in the z-direction can, for example, be easily provided by embossing the separating element 44. Furthermore, a spacer element 62, made of any material, can be arranged between the edge region 58 of the battery module 32 and the separating element 44. Adhesive can also be applied between such spacers or spacer elements 62 and the battery module 32 or the separating element 44. This advantageously allows for particularly easy removal of the battery modules 32 or separation from the separating element 44, for example, using a wire saw. These spacers 62 allow a hot wire to be inserted between the battery module 32 and the separating element 44 in a particularly simple manner, and in particular to cut the connection z between the battery module 32 and the separating element 44 along the cutting line 64 shown here. Thus, these spacers 62 advantageously enable the saw wire to be inserted underneath.In the event of customer service or for the recycling of the battery assembly 30, the battery modules 32 can advantageously be separated again from the housing, in particular from the cooling device 36. Overall, the examples show how the invention enables an alternative battery concept which, by providing a bonded module set, in particular suspended from the support frame, with an external tolerance compensation, makes it possible to forego the use of conventional gap fillers for tolerance compensation, as well as additional tolerance compensation elements, elaborate gap filler injection processes and additional screw connections between the cooling floor and the support structure. The proposed concept allows for the flexible use of more flexible module sizes, and especially larger battery modules, and also increases cooling efficiency in many ways.

Claims

Battery assembly method for providing a battery arrangement (30) with at least one battery module (32), a cooling device (36) for cooling the at least one battery module (32), and a frame (38), wherein the at least one battery module (32) is attached to a first side (36a) of the cooling device (36), and the frame (38) is attached to at least the at least one battery module (32), characterized in that: - to attach the at least one battery module (32) to the first side (36a) of the cooling device (36), the at least one battery module (32) is glued in a module support area (44a) of the first side (36a) of the cooling device (36), without the frame (38) being attached to the cooling device (36); - wherein the cooling device (36) has a separating element (44) providing the first side (36a), which has an edge area (44c) and a transition area (44b).which connects the edge region (44c) with the module support region (44a), wherein the separating element (44) is elastically flexible at least in the transition region (44b), and wherein, after the at least one battery module (32) has been glued on, the frame (38) is placed on the arrangement of the at least one battery module (32) and the cooling device (36) in such a way that at least a part (38b) of the frame (38) rests on the edge region (44c) of the separating element (44). Battery assembly method according to claim 1, characterized in that the separating element (44) is provided as a sheet (44) with a maximum thickness of one millimeter. Battery assembly method according to one of the preceding claims, characterized in that several battery modules (32) are glued onto the module support area (44a) of the first side (36a) of the cooling device (36), wherein the battery modules (32) are fixed in their arrangement relative to each other before being arranged in the module support area (44a) and the fixed arrangement of the battery modules (32) is placed on the first side (36a) of the cooling device (36) and glued on. Battery assembly method according to one of the preceding claims, characterized in that after the frame (38) is placed on the frame, the frame (38) is screwed to the at least one battery module (32), so that in the screwed state of frame (38) and the at least one battery module (32) a part (38a) of the frame (38), which is integrally formed with the frame (38), is in direct contact with a part (32a) of the at least one battery module (32). Battery assembly method according to one of the preceding claims, characterized in that after placing the frame (38) the frame (38) is screwed to the separating element (44) only in the edge area (44c) of the separating element (44). Battery assembly method according to one of the preceding claims, characterized in that the frame (38) has struts (38b, 38c) which, in the state of the frame (38) being placed on the arrangement of the at least one battery module (32) and the cooling device (36), extend perpendicularly at least to the module support area (44a) of the separating element (44), wherein the struts (38b, 38c) have a widening (38a) on a side facing away from the separating element (44), which forms a projection (38) which projects in a direction perpendicular to the direction of travel of the struts (38b, 38c) over at least a part (32a) of the at least one battery module (32) and which has at least one screw hole (54), wherein, for screwing the frame (38) to the at least one battery module (32), a screw (52) passes through the screw hole (54) and at least partially into or through the part (32a) of the battery module. (32) is screwed. Battery assembly method according to claim 6, characterized in that several screw holes (54) are arranged in the projection (38a) at a certain distance from each other in a longitudinal extension direction of the projection (38a), wherein screw holes (54) used for screwing the frame (38) to the battery modules (32) are selected from the several screw holes (54) depending on the respective module sizes of the battery modules (32) and / or on an arrangement of the battery modules (32) relative to each other. Battery assembly method according to one of the preceding claims, characterized in that the separating element (44) is unevenly formed, so that the first side (36a) provided by the separating element (44) is raised in the central module support area (44a) for the at least one battery module (32) compared to an edge area of ​​the module support area (44a). Battery assembly method according to one of the preceding claims, characterized in that a module base which, after arrangement of the at least one battery module (32) on the cooling device (36), faces the cooling device (36), is uneven, so that the module base is raised in a central area (60) compared to an edge area (58) of the module base, in particular wherein a spacer element (62) with a thickness of at most one millimeter is arranged between the edge area (58) of the module base and the separating element (44).

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