Method for manufacturing a battery assembly with a metallic tension band with force-fit connected tension band ends, battery assembly and motor vehicle with such a battery assembly

Abstract

A method (500) for manufacturing a battery assembly (10) for an electrically powered motor vehicle (200) is described, comprising the steps: providing (S501) several cuboid-shaped battery cells (12); providing (S502) two axial end plates (14); arranging (S503) the battery cells (12) between the axial end plates (14) in a stack; compressing (S504) the stack by applying a temporary axial pressing force to the end plates (14) to form a compressed stack; folding (S505) at least one tension band (16) made of a metal surrounding the compressed stack such that the ends (16e) of the tension band (16) lie on top of each other in an overlap area (18); Force-locking and / or material-locking connection (S506) of the ends (16e) of the tension band (16) in the overlap area (18) so that a closed tension band ring is formed;Termination (S507) of the application of the pressing force to the end plates (16), wherein, during axial expansion of the stack, the at least one tension band (16) continues to exert a pressing force on the stack. Furthermore, a battery arrangement 10 and a motor vehicle (200) with such a battery arrangement (10) are described.

Description

[0001] The invention relates to a method according to the preamble of claim 1 for manufacturing a battery assembly for an electrically powered motor vehicle, comprising the steps of: providing several cuboid-shaped battery cells; providing two axial end plates; arranging the battery cells between the axial end plates in a stack; and compressing the stack by applying a temporary axial pressing force to the end plates to form a compressed stack. The invention further relates to a battery assembly and a motor vehicle with at least one such battery assembly.

[0002] Such a method is known, for example, from DE 10 2014 219 644A1 or DE 10 2023 112 745 A1. A further method is known from the prior art, for example, from DE 10 2016 200 496 A1, wherein the stack is clamped by means of a plastic band that is bonded, in particular glued, to plastic end plates. Reference is also made to DE 10 2023 123 494 B3, DE 10 2022 101 725 A1 and DE 10 2009 029 019 A1.

[0003] In such battery configurations, the battery cells are stacked, pressed, and packaged for module production. To hold the stack of battery cells together, a pre-assembled tension band is fitted over it, and the cell stack relaxes within the tension band or is compressed and held together by the tensioning mechanism. Pre-assembling tension bands is only feasible for small battery cell stacks, because clamping elements that compress the battery cell stack would block the pre-assembled tension band's access to the stack or its end plates.

[0004] The object underlying the invention is seen as being to provide a method for manufacturing a battery arrangement in which higher pressing forces can be applied and absorbed in the finished battery arrangement by means of the tension band.

[0005] This problem is solved by a method, a battery arrangement, and a motor vehicle with the features of the respective independent patent claim. Advantageous embodiments with expedient further developments are specified in the dependent patent claims.

[0006] The proposed method is for manufacturing a battery assembly for an electrically powered motor vehicle, comprising the steps of: providing several cuboid-shaped battery cells; Providing two axial end plates; Arranging the battery cells between the axial end plates in a stack; Compressing the stack by applying a temporary axial pressing force to the end plates to form a compressed stack; Folding over at least one tension band made of metal encircling the compressed stack, such that the ends of the tension band lie on top of each other in an overlap area; Force-locking and / or material-locking connection of the ends of the tension band in the overlap area, so that a closed tension band ring is formed; Termination of the application of the pressing force to the end plates, whereby, in the event of axial expansion of the stack, at least one tension band continues to exert a pressing force on the stack.

[0007] By using at least one circumferential tension band made of metal, higher forces can be transmitted and creep, as occurs with a known plastic band, can be avoided.

[0008] In this process, the axial end plates can be made of a metal, particularly aluminum. This allows higher forces to be transmitted or absorbed via the end plates.

[0009] In this process, the tension band can be made of stainless steel.

[0010] In this process, the force-fit and / or material-fit connection of the ends of the tension band can be achieved by one of the following methods. Resistance spot welding, Metal inert gas welding, Laser remote welding, Ultrasonic welding, Insertion of at least one bolt, in particular by means of high speed (RIVTAC), Clamps.

[0011] These joining methods can be carried out either on one side of the overlap area or on both sides of the overlap area.

[0012] In this process, the tension band is folded over in such a way that the overlap area of ​​the ends of the tension band is arranged in the area of ​​an axial end face of one of the end plates.

[0013] The frictional and / or material-locking connection of the ends of the tension band is achieved in such a way that the respective end plate remains unprocessed. This prevents a material-locking connection between the at least one tension band and the end plate. In other words, the at least one tension band rests only against the end plates. This is particularly advantageous when using a tension band made of stainless steel and an end plate made of another metal, especially aluminum, because it prevents the formation of brittle intermetallic phases.

[0014] In this method, the end plate in question can have at least one recess in its face, with the overlap area of ​​the ends of the tension band being positioned opposite the recess, so that the overlap area is accessible from two sides. This allows for two-sided machining when joining the two ends of the tension band.

[0015] Furthermore, a battery arrangement for an electrically powered motor vehicle is proposed, wherein the battery arrangement comprises: several battery cells arranged axially between two end plates and held together by at least one circumferential tension band, wherein the battery arrangement has been manufactured according to the method described above.

[0016] In the battery arrangement, at least one of the two end plates can have at least one recess, wherein an overlap area of ​​the ends of the at least one tension band can be arranged opposite the recess.

[0017] Furthermore, a motor vehicle with an electric drive and with at least one battery arrangement described above is proposed.

[0018] Further advantages and details of the invention will become apparent from the following description of embodiments with reference to the figures. These show: Fig. 1. A simplified and schematic sectional view of a battery arrangement in a motor vehicle, Fig. 2 a simplified and schematic top view of an end plate of a battery assembly approximately corresponding to a contour arrow II of the Fig. 1; Fig. 3 a simplified diagram of a manufacturing process for a battery assembly; Fig. Figure 4 simplifies and schematically shows several examples of the design of end plates with recesses for the battery arrangement.

[0019] In Fig. Figure 1 shows a simplified and schematic cross-sectional view of a battery arrangement 10. The battery arrangement 10 comprises several battery cells 12 arranged side by side in an axial direction AR, in particular stacked. The battery cells 12 are held in the axial direction AR between two end plates 14. It should be noted that the end plates 14 do not necessarily have flat or planar surfaces or sides, even though they are referred to as "plates" in this description.

[0020] The battery assembly 10 further comprises at least one tension band 16 arranged around the battery cells 12 and the end plates 14. The tension band 16 has ends 16e which are connected to each other in an overlap area 18 by frictional and / or material interlocking. This is shown in Fig. 1 is simplified and schematically shown on the left side of the battery arrangement 10. For the sake of completeness, it should be noted that a cell separator 20 is visible between adjacent battery cells 12.

[0021] In the Fig. Figure 2 is a simplified and schematic top view in the axial direction of an end face 14s of the end plate 14 of the battery assembly 10. Two tension bands 16 are illustrated as examples, with the overlap area 18 of the ends of the tension bands 16 being illustrated by means of the dashed and solid lines.

[0022] From the Fig. Figure 2 shows, based on the exemplary illustration on the left, that at least one recess 22 is arranged in the end face 14s of the end plate 14. This illustration also shows that the overlap area 18 of the ends of the tension band 16 can be, or is, arranged opposite the recess 22. The exemplary illustration on the right shows that a recess 22 is not necessarily required in the end face 14s, but that the overlap area 18 can also be in direct contact with the end face 14s of the end plate 14.

[0023] The presentation of Fig. Figure 2 shows, purely by way of example, two possible designs of end plates 14 using a single drawing. Typically, an end plate 14 of a battery arrangement 10 with two tension bands 16 would have either two (respective) recesses 22 or no recesses.

[0024] The end plates 14 can be made of plastic or metal, in particular aluminum. The tension band 16 is made of metal, in particular stainless steel.

[0025] A battery arrangement 10 can be manufactured according to a method 500, which is simplified and schematically described in Fig. 3 is shown.

[0026] According to step S501, several cuboid-shaped battery cells 12 are provided.

[0027] According to step S502, two axial end plates 14 are provided.

[0028] According to step S503, the battery cells 12 are arranged in a stack between the axial end plates 14.

[0029] The stack is compressed into a compact stack according to step S504 by applying a temporary axial pressing force to the end plates 16.

[0030] According to step S505, at least one tension band 16 made of metal encircling the compressed stack is folded over such that the ends 16e of the tension band 16 lie on top of each other in an overlap area 18.

[0031] In step S506, the ends 16e of the tension band 16 were joined by force-locking and / or material-locking connection in the overlap area 18, so that a closed tension band ring is formed.

[0032] According to step S507, the application of the pressing force to the end plates 14 is terminated, whereby during an axial expansion of the stack, at least one tension band 16 continues to exert a pressing force on the stack.

[0033] In method 500, step S506, i.e., the force-fit and / or material-fit connection of the ends 16e of the tension band 16, can be carried out by one of the following methods or techniques: Resistance spot welding, Metal inert gas welding, Laser remote welding, Ultrasonic welding, Insertion of at least one bolt, in particular by means of high speed (RIVTAC), Clamps.

[0034] In method 500, the tension band 16 is folded over in step S505 such that the overlap area 18 of the ends 16e of the tension band 16 is arranged in the area of ​​an axial end face 14s of one of the end plates 14.

[0035] The force-fit and / or material-fit connection of the ends 16e of the tension band 16 is carried out according to step S506 in such a way that the relevant end plate 14 remains unprocessed.

[0036] The end plate 14 in question can have at least one recess 22 in its end face 14s, wherein the overlap area 18 of the ends 16e of the tension band 16 is positioned opposite the recess 22 during step S505, so that the overlap area 18 is accessible from two sides. This allows the force-fit and / or material-fit connection of the two ends 16 of the tension band 16 to be established from two sides.

[0037] In particular, part of a joining tool, such as a welding device or the like, can be inserted into the recess 22 and face an inside of the overlap area 18, with another part of the joining tool facing an outside of the overlap area 18.

[0038] If a recess 22 is present behind the overlap area 18, the two ends 16 of the tension band 16 can also be connected to each other by at least one bolt which is moved at high speed through the two overlapping ends 16e, which can also be referred to as RIVTAC.

[0039] In the Fig. Figure 4 shows simplified and schematic possible configurations of an end plate 14 and a part of the circumferential tension band 16. From the Fig. For example, it can be seen in Figure 4 that the end plate 14 can have an essentially straight or flat front face 14s, as shown in the two examples on the left.

[0040] The end plate 14 can also have a curved, in particular convex, end face 14s, as shown in the two right-hand examples of the Fig. 4 is shown.

[0041] From the Fig. Figure 4 further shows that one or more recesses 22 can be arranged in an end plate 14. If only one recess 22 is provided, as is the case (counting from the left) in the first and third examples of the Fig. 4. In this case, the overlap area 18 can be smaller than if two (or more) recesses 22 are provided (second and fourth examples).

[0042] If several recesses 22 are provided in the end face 14s of the end plate 14, a material-locking and / or force-locking connection of overlapping ends of the tension band 16 can be made or have been made in the area of ​​each recess 22.

[0043] From the right-hand example of the Fig. 4 shows that the recesses 22 can be filled with a material 24, for example a plastic material, particularly after the force-fit and / or material-fit connection of the ends of the tension band 16 has been made, so that compressive forces can also be distributed or absorbed via the filled recesses 22.

[0044] A battery arrangement 10 described above, in particular according to method 500 ( Fig. 3) has been manufactured, may be part of a Fig. 1 motor vehicle 200 represented as a dashed rectangle, in particular a vehicle 200 with a purely electric drive or with a hybrid drive.

[0045] In the above-described method 500 or in the described battery arrangement 10, the end plate 14 can be manufactured, in particular, as an extruded aluminum profile. This can be used with at least one stainless steel tension band 16. The use of at least one stainless steel tension band allows for the transmission of higher forces and prevents creep, as is known from plastic bands. A particularly adapted design of the aluminum end plate 14 with a recess 22 allows for access from both sides or provides a counter-position for one-sided spot welding.

[0046] A pressing device (not shown here) for compressing the battery cell stack can be designed in such a way as to allow access for repositioning the tensioning straps when the battery cells are clamped. The joining operation (connecting) of the tensioning strap ends can then be carried out while the device remains in this position.

[0047] The various joining methods that can be used in the overlap area can influence the geometry of the end plate, in particular whether your end plate is designed with or without a recess, either to create space for a joining element (bolts in the case of RIFTAC) or to avoid welding the stainless steel tension band to the aluminum extrusion profile, for example during laser welding.

[0048] When joining using resistance spot welding, it can be particularly advantageous to increase the material thickness of the aluminum extrusion profile in the joining area to create a counter-surface for the welding force and to ensure that the overlapping area of ​​the tension band rests on the aluminum end plate. Direct welding of the stainless steel band to the aluminum end plate must be strictly avoided due to the formation of brittle intermetallic phases; this can be achieved using the method and battery arrangement described above.

Claims

[1] Method (500) for manufacturing a battery assembly (10) for an electrically powered motor vehicle (200), comprising the steps: Providing (S501) several cuboid battery cells (12); Providing (S502) two axial end plates (14); Arranging (S503) the battery cells (12) between the axial end plates (14) in a stack; Compression (S504) of the stack by applying a temporary axial pressing force to the end plates (14) to form a compressed stack; Folding (S505) of at least one tension band (16) made of a metal circumferential around the compressed stack, such that the ends (16e) of the tension band (16) lie on top of each other in an overlap area (18), wherein the tension band (16) is folded such that the overlap area (18) of the ends (16e) of the tension band (16) is arranged in the area of ​​an axial end face (14s) of one of the end plates (14); Force-locking and / or material-locking connection (S506) of the ends (16e) of the tension band (16) in the overlap area (18) so that a closed tension band ring is formed; Termination (S507) of the application of the pressing force to the end plates (16), wherein, in the event of axial expansion of the stack, at least one tension band (16) continues to exert a pressing force on the stack. characterized by , that the force-fit and / or material-fit connection of the ends (16e) of the tension band (16) is carried out in such a way that the end plate (14) in question remains unworked. [2] Method (500) according to claim 1, wherein the axial end plates (14) are made of a metal, in particular aluminium. [3] Method (500) according to claim 1 or 2, wherein the tension band (16) is made of stainless steel. [4] Method (500) according to one of the preceding claims, wherein the force-fit and / or material-fit connection (S506) of the ends (16e) of the tension band (16) is carried out by one of the following methods: Resistance spot welding, Metal inert gas welding, Laser remote welding, Ultrasonic welding, Insertion of at least one bolt, in particular by means of high speed (RIVTAC), Clamps. [5] Method (500) according to one of the preceding claims, wherein the end plate (14) in question has at least one recess (22) in the end face (14s), wherein the overlap area (18) of the ends (16e) of the tension band (16) is arranged opposite the recess (22) so that the overlap area (18) is accessible from two sides. [6] Battery arrangement (10) for an electrically powered motor vehicle (200), wherein the battery arrangement (10) comprises: several battery cells (12) arranged in the axial direction (AR) between two end plates (14) and held together in a compressed manner by at least one circumferential tension band (16), wherein the battery arrangement (10) has been manufactured according to the method (500) according to one of the preceding claims. [7] Battery arrangement (10) according to claim 6, characterized by , that at least one of the two end plates (14) has at least one recess (22), and that an overlap area (18) of ends (16) of the at least one tension band (16) is arranged opposite the recess (22). [8] Motor vehicle (200) with an electric drive and with at least one battery arrangement (10) according to claim 6 or 7.

Images