Method for manufacturing a vehicle battery, vehicle battery and motor vehicle

Abstract

Method for manufacturing a vehicle battery (4), in particular a motor vehicle battery (1), wherein according to the method - at least one cuboid battery cell (8) is provided, - a planar hook and loop semi-finished product (12) is provided for the respective battery cell (8), - the hook and loop semi-finished product (12) is cut into an unwound folded blank (14) for the respective battery cell (8), wherein the folded blank (14) is formed with a carrier layer extending over all surface sections (18), wherein the carrier layer carries hook and loop elements in corresponding surface sections (18), and wherein the carrier layer and the hook and loop elements are made of a polyolefin, in particular a polypropylene, and - the folded blank (14) is folded and applied to the respective battery cell (8) such that the respective battery cell (8) is at least partially covered on each cuboid outer surface (16) with a surface section (18) of the folded blank (14).

Description

[0001] The invention relates to a method for manufacturing a vehicle battery. The invention also relates to a vehicle battery, preferably manufactured using the method, and to a motor vehicle.

[0002] Electrically powered or electromechanically driven motor vehicles, such as electric or hybrid vehicles, generally include an electric motor that drives one or both axles. To supply electrical energy, the electric motor is usually connected to an internal (high-voltage) battery, which serves as an electrical energy storage device.

[0003] In this and the following, the term "electrochemical battery" refers specifically to a so-called secondary battery of a motor vehicle. In such a (secondary) vehicle battery, the chemical energy consumed can be replenished by means of an electrical (re)charging process. These types of vehicle batteries are, for example, designed as electrochemical accumulators, particularly as lithium-ion accumulators.

[0004] To generate or provide a sufficiently high operating voltage, such vehicle batteries typically have at least one battery module (battery cell module) in which several individual battery cells are modularly connected. Alternatively, a so-called Cell2Pack or Cell2Car design is possible, in which the battery cells are directly connected to form the vehicle battery, particularly in parallel, and are not grouped into modules beforehand.

[0005] During assembly, the individual battery cells are bonded into a module or pack using adhesives or gap fillers. A gap pad is typically placed between adjacent battery cells to compensate for volume changes within the cell stack during charging and discharging (cell breathing). These gap pads also compensate for the age-related increase in cell thickness over the battery cells' lifespan (cell swelling). The battery cells are bonded with a gap filler, particularly on their cooling connection side, and positioned with gap pads in the swelling direction. They are otherwise mechanically secured within the battery system (welded, mounted, etc.), preventing subsequent repositioning of the battery cells within the cell stack.

[0006] From US 2007 / 0224498 A1, it is known to provide the facing end faces of the battery cells with hook-and-loop fasteners and to stack them vertically into a cell stack connected by hook-and-loop fasteners. JP 2012-119131 A describes how such a vertically oriented cell stack is connected by hook-and-loop fasteners at its end faces to a lid-side and a bottom-side housing surface.

[0007] The invention is based on the objective of enabling a particularly suitable vehicle battery.

[0008] The problem is solved according to the invention by a method having the features of claim 1. Furthermore, this problem is solved according to the invention by a vehicle battery having the features of claim 8. Furthermore, this problem is solved according to the invention by a motor vehicle having the features of claim 14. Advantageous embodiments and further developments are the subject of the dependent claims.

[0009] The method according to the invention serves to manufacture a vehicle battery, which is designed and intended for use in a (preferably wheeled and road-bound) motor vehicle.

[0010] According to the method, at least one cuboid-shaped battery cell (preferably several) is initially provided. A flat hook-and-loop fastener is provided for the respective battery cell, and the hook-and-loop fastener is trimmed (or cut) into a folded, unrolled blank for the respective battery cell. This folded blank is then folded and applied to the respective battery cell in such a way that the respective battery cell is at least partially covered on each of its cuboid outer surfaces with a surface section of the folded blank.

[0011] In other words, each battery cell is folded into a pre-cut blank. This allows the battery cell to be relatively easily "attached" to other battery cells or battery components using a hook-and-loop fastener. Furthermore, this method also allows for relatively simple electrical insulation of each battery cell.

[0012] The terms "Hook and loop," "Hook and loop," or "Hook and loop connection" here and below refer specifically to a reversibly detachable, positive and non-positive (quick-release) connection between two hook and loop surfaces. The hook and loop connection or hook and loop fastener is based on the principle of velcro. This means that the hook and loop surfaces have complementary hook and loop elements (in particular, hook and loop eyelets, or so-called mushroom-head pins), which are held together in a positive and non-positive manner in the hook and loop connection and can be separated from each other, in particular by peeling.

[0013] In a preferred process variant, the hook and loop fastener semi-finished product or the folding blank is provided in some areas without hook and loop elements, in particular without hook and loop hooks or mushroom pins. In other words, the hook and loop fastener semi-finished product or at least the folding blank has areas in which no hook and loop elements, specifically, for example, hook and loop hooks, are arranged. These areas are preferably many times larger than the area around a single hook and loop element, which is already free of hook and loop elements (due to the spacing between the individual hook and loop hooks or mushroom pins).

[0014] This partial recession of hook-and-loop fasteners advantageously improves the handling of the battery cells fitted with the folded blank. This reduces or even eliminates the risk of the individual battery cell snagging on a handling tool that engages a recessed area of ​​the folded blank.

[0015] In a suitable process variant, the folded blank is glued to the respective cuboid outer surface. In particular, an adhesive layer is inserted between the respective cuboid outer surface and the folded blank. Gluing advantageously enables – especially with a suitable adhesive selection – an electrical insulation effect and thus at least almost complete electrical insulation of the respective battery cell, for example, except for specific recesses for the passage of contacting means.

[0016] In a particularly advantageous variant of the process, a reactive adhesive, especially one that cures through radiation or heat, and in particular an acrylate, polyurethane, or epoxy resin, is used for the adhesive layer. Preferably, the adhesive is selected such that, in the cured state, it exhibits an adhesive layer strength between 2 and 50 MPa.

[0017] In a preferred further development, the adhesive layer is applied to the reverse side of the hook and loop material. In particular, the hook and loop material is provided with this adhesive layer already applied. In this case, the hook and loop material thus represents a type of adhesive tape.

[0018] In an alternative development, however, the adhesive layer is applied to the outer cuboid surfaces of the respective battery cell before the folding cut is applied.

[0019] The vehicle battery according to the invention is designed, in particular, as a traction battery for an electrically powered or motorized motor vehicle, for example, an electric or hybrid vehicle. The vehicle battery preferably comprises a battery housing with a pot- or tub-shaped battery compartment and a housing cover (battery cover) that closes or covers this compartment. The vehicle battery further comprises at least one cuboid-shaped battery cell (in particular, the one described above) and an outer layer applied to the battery cell, which is formed by a folded blank (in particular, the one described above). The folded blank is cut, folded, and applied to the respective battery cell in such a way that the respective battery cell is at least partially covered on each outer surface of the cuboid by a section of the folded blank.At least some of the surface sections of the folded blank preferably have hook-and-loop fasteners on their outer surface. Furthermore, the battery box preferably has a base (battery bottom) arranged opposite the housing cover, which, in an installed state, forms the bottom surface of the battery housing. Several of the aforementioned battery cells are preferably arranged in the battery housing. The vehicle battery is designed in particular according to a Cell2Pack or Cell2Car design, so that the battery cells are inserted directly into the battery housing and are not combined into (battery) modules. However, the following descriptions and examples can also be applied analogously to a battery module with a module housing comprising a module base and a module cover.

[0020] In particular, the vehicle battery is the vehicle battery described above in the context of the method according to the invention. The vehicle battery and its optional design variants described in more detail below thus have the same advantages that also result from the method described above. In optional designs, the vehicle battery also has the physical features resulting from the method described above.

[0021] "At least partially covered by the surface section" is understood here and below in particular to mean that parts of one or more cuboid outer surfaces are not (fully) covered by a surface section. This is useful, for example, for feedthroughs of contact elements between individual battery cells or from a battery cell to a higher-level interconnection unit.

[0022] Advantageously, a portion of the surface sections of the folded blank is designed without hook-and-loop elements on the outside, i.e., in particular without the hook-and-loop hooks or mushroom-head pins described above. Preferably, the hook-and-loop semi-finished product is manufactured partially without these elements, or the elements are removed (e.g., mechanically) in the corresponding areas.

[0023] In a preferred embodiment, the folded blank is designed with a support layer extending over all surface sections. This support layer carries the aforementioned hook-and-loop elements, in particular hook-and-loop hooks, in corresponding surface sections (preferably only in these surface sections, not in other surface sections).

[0024] In a practical embodiment, the aforementioned carrier layer is made of a polyolefin, in particular polypropylene. The carrier layer preferably has a thickness of 1 to 200 µm, more preferably 10 to 100 µm. Particularly preferably, the carrier layer has a thickness of at least 25 µm (in particular up to approximately 100 µm). This small thickness contributes to comparatively good thermal conductivity throughout the outer layer. The carrier layer made of plastic, specifically polyolefin, which extends across all surface sections, advantageously enables electrical insulation of the exterior of the battery cell.

[0025] However, the invention also allows for the carrier layer (and optionally the hook-and-loop fasteners) to be made of a metal, e.g., aluminum. In this case, the electrical insulation described above is preferably achieved by means of the adhesive layer.

[0026] In a further expedient embodiment, the Velcro elements are (in particular also) formed from a (or the above-mentioned) polyolefin.

[0027] In a preferred embodiment, the folded blank is glued to the respective cuboid outer surface. In particular, a reactive adhesive, particularly one that cures through radiation or heat, is used as the adhesive, particularly an acrylate, polyurethane, or epoxy resin.

[0028] Preferably, the adhesive in the cured state has an adhesive layer strength of between 2 and 50 MPa.

[0029] The motor vehicle according to the invention comprises the vehicle battery described above.

[0030] In the following, exemplary embodiments of the invention are explained in more detail with reference to a drawing. In the drawings: Fig. 1 shows a schematic side view of a battery-electric motor vehicle, Fig. 2 In a top view, schematically a folded cutout made of a hook and loop fastener semi-finished product for a battery cell of a vehicle battery of the motor vehicle, and Fig. 3 In a perspective view, schematically the battery cell with applied folding cut.

[0031] Corresponding parts and sizes are always marked with the same reference symbols in all figures.

[0032] In Fig. Figure 1 schematically depicts a motor vehicle, specifically a passenger car 1. This vehicle includes an electric drive in the form of an electric motor 2, which acts on a drive axle of the passenger car 1 in a manner not shown. The passenger car has a (traction or vehicle) battery 4 to supply energy to the electric motor 2. Thus, the passenger car 1 is a battery-electric vehicle.

[0033] The battery 4 comprises several rows 6 (only two are shown here) of battery cells 8 arranged in a row. These battery cells 8 are cuboid-shaped (i.e. with a rectangular cross-section) (see Fig. 3) trained and interconnected.

[0034] In order to enable the battery cells 8 to be mounted as flexibly as possible in a larger battery housing 10, the battery cells 8 are provided with Velcro surfaces.

[0035] For this purpose, a Velcro semi-finished product 12 (see above) is first used. Fig. 2) A folded blank 14 is separated and cut so that a surface section 18 of the surface section 14 is available for each cuboid outer surface 16. Compared to an originally rectangular shape of the hook and loop semi-finished product 12, the remaining sections 20 in this case represent waste or can even, through suitable positioning of the folded blanks 14 on the hook and loop semi-finished product 12, become part of another folded blank 14.

[0036] The folded blank 14 is then folded between the surface sections 18 and applied to the cuboid outer surfaces 16, i.e., attached to them.

[0037] In the present exemplary embodiment, the folded blank 14 has a carrier layer that extends over all surface sections 18. This carrier layer carries hook-and-loop elements, specifically hook-and-loop hooks or mushroom-head pins, only in the surface sections 18 assigned to the long cuboid outer surfaces 16, but not on the surface sections 18 assigned to the end surfaces 22. Optionally, surface sections 18 are assigned to the flat sides 24, one of which carries hook-and-loop hooks and the other hook-and-loop eyelets, or both surface sections 18 carry mushroom-head pins. This allows the battery cells 8 to be hooked together with their flat sides 24. Due to the hook-and-loop elements also present on the narrow longitudinal surfaces, the respective battery cell 8 can also be arranged and fastened in the battery housing 10, specifically between a base plate 26 and a cover plate 28.

[0038] The backing layer is made of a polyolefin, specifically polypropylene. The hook-and-loop fasteners are also made of a polyolefin.

[0039] In each of the end faces 22, a window 30 is cut out in the surface sections 18 assigned to it. This serves as a window in the intended assembly state (see below). Fig. 3) the provision of contact means to and from the respective battery cell 8.

[0040] The folded blank 14 has an adhesive layer (not shown) applied to its reverse side, which is used to attach the folded blank 14 to the battery cell 8. To achieve a sufficiently high tensile strength during use, a radiation-cured (e.g., UV-cured) acrylate is used, enabling a strength of up to 50 MPa. The adhesive layer has a thickness of between 10 and 20 µm.

[0041] The backing layer and the hook and loop elements are selected or designed in such a way that a complete hook and loop connection achieves a thickness between 1 and 10 mm.

[0042] The hook and loop fasteners are also arranged with a distance of between 0.5 and 3 mm from each other.

[0043] Alternatively, the adhesive layer can first be applied to the outer surfaces of the cuboid 16 and then the folded cutout 14 can be applied to the outer surfaces of the cuboid 16.

[0044] The subject matter of the invention is not limited to the embodiments described above. Rather, further embodiments of the invention can be derived by a person skilled in the art from the foregoing description. In particular, the individual features of the invention and their various configurations described with reference to the different embodiments can also be combined with one another in other ways. List of reference symbols 1 motor vehicle 2 electric motor 4 batteries 6 row 8 battery cells 10 battery cases 12 Hook and loop fasteners 14 Folded cut 16 cuboid outer surface 18 Area section Section 20 22 Front surface 24 flat page 26 Base plate 28 Cover plate 30 windows QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] US 2007 / 0224498 A1

[0006] JP 2012119131 A

[0006]

Claims

[1] Method for producing a vehicle battery (4), in particular of a motor vehicle (1), wherein according to the method - at least one cuboid battery cell (8) is provided, - a flat Velcro semi-finished product (12) is provided for the respective battery cell (8), - the hook and loop semi-finished product (12) is cut into a folded blank (14) for the respective battery cell (8), - the folding blank (14) is folded and applied to the respective battery cell (8) in such a way that the respective battery cell (8) is at least partially covered on each cuboid outer surface (16) with a surface section (18) of the folding blank (14). [2] Method according to claim 1, wherein the hook and loop semi-finished product (12) is provided in some areas without hook and loop elements, in particular without hook and loop hooks or mushroom head pins. [3] Method according to claim 2, wherein the hook and loop semi-finished product (12) is provided with at least two surface sections (18) of the folding blank (14), which are preferably assigned to mutually opposite cuboid outer surfaces (16) of the respective battery cell (8), which do not have any hook and loop elements. [4] Method according to one of claims 1 to 3, wherein the folding blank (14) is glued to the respective cuboid outer surface (16) by means of an adhesive layer. [5] Method according to claim 4, wherein a reactive, in particular radiation- or heat-induced curing adhesive, in particular an acrylate, polyurethane or epoxy resin, is used for the adhesive layer, preferably wherein the adhesive in the cured state has an adhesive layer strength of between 2 and 50 MPa. [6] Method according to claim 4 or 5, wherein the adhesive layer is applied to the back of the hook and loop semi-finished product (12). [7] Method according to claim 4 or 5, wherein the adhesive layer is applied to the cuboid outer surfaces (16) of the respective battery cell (8) before the application of the folding blank (14). [8] Vehicle battery (4), in particular for a motor vehicle (1), comprising - at least one cuboid battery cell (8), - an outer layer formed by a folding blank (14) which is cut, folded and applied to the respective battery cell (8) in such a way that the respective battery cell (8) is at least partially covered on each cuboid outer surface (16) with a surface section (18) of the folding blank (14), wherein at least some of the surface sections (18) of the folding blank (14) carry hook-and-loop elements on the outside. [9] Vehicle battery (4) according to claim 8, wherein a part of the surface sections (18) of the folding blank (14) is formed on the outside without Velcro elements. [10] Vehicle battery (4) according to claim 8 or 9, wherein the folding blank (14) is formed with a carrier layer extending over all surface sections (18), wherein the carrier layer carries hook and loop elements in corresponding surface sections (18). [11] Vehicle battery (4) according to claim 10, wherein the carrier layer is formed from a polyolefin, in particular a polypropylene, in particular wherein the carrier layer has a thickness of 1 to 200 µm, preferably of 10 to 100 µm, particularly preferably of at least 25 to 100 µm. [12] Vehicle battery (4) according to claim 10 or 11, wherein the Velcro elements are formed from a polyolefin. [13] Vehicle battery (4) according to one of claims 8 to 12, wherein the folding blank (14) is glued to the respective cuboid outer surface (16), in particular wherein a reactive, in particular radiation- or heat-induced curing, adhesive, in particular an acrylate, polyurethane or epoxy resin, is used as the adhesive, preferably wherein the adhesive in the cured state has an adhesive layer strength of between 2 and 50 MPa. [14] Motor vehicle (1) with a vehicle battery (4) according to one of claims 8 to 13.

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