busbar and electrical energy storage

Abstract

The invention relates to a busbar (1) for electrically connecting individual cells (2) of an electrical energy storage device. According to the invention, the busbar (1) is formed by a web-shaped bridge element (1.3) and a plurality of planar, arc-shaped current contact elements (1.1), wherein a current contact element (1.1) for electrically connecting two adjacent individual cells (2) is arranged and / or formed at one end of a torsion bar (1.2) projecting from the bridge element (1.3), and a bearing edge (1.1.1) of the current contact element (1.1) arranged parallel to the longitudinal axis of the torsion bar (1.2) is formed for resting on a pole contact (2.1) of an individual cell (2), and a further bearing edge (1.1.2) of the current contact element (1.1) running parallel to the opposite bearing edge (1.1.1) is formed for resting on a pole contact (2.1) of an adjacent individual cell (2).Furthermore, the invention relates to an electrical energy storage device.

Description

[0001] The invention relates to a busbar for electrically connecting individual cells of an electrical energy storage device. Furthermore, the invention relates to an electrical energy storage device with a plurality of individual cells, wherein at least two adjacent individual cells are electrically connected by means of such a busbar.

[0002] DE 10 2021 005 574 A1 discloses a method for producing a welded joint between three components using energy radiation, a component assembly produced using such a method, a battery having such a component assembly, and a motor vehicle having such a battery. The method provides that a first lower edge of an upper component of the three components is arranged on a first lower component of two lower components of the three components in such a way that the first lower edge of the upper component rests on a first contact surface of the first lower component, thereby forming a first connection region.In this case, a second lower edge of the upper component, opposite the first lower edge in a connecting direction of the two lower components, is arranged on a second lower component of the two lower components in such a way that the second lower edge of the upper component rests on a second contact surface of the one second lower component, thereby forming a second connecting region. The upper component is arranged on the one first lower component and on the one second lower component such that a concave boundary surface of the upper component, arranged between the first lower edge and the second lower edge, faces the one first lower component and the one second lower component.The upper component is subjected to an energy beam in the one first connection region and in the one second connection region, wherein the energy beam is displaced in a weld seam direction in regions along the first lower edge of the upper component and in regions along the second lower edge of the upper component, so that in the one first connection region the first lower edge of the upper component is welded to the one first lower component by forming a first weld seam and in the one second connection region the second lower edge of the upper component is welded to the one second lower component by forming a second weld seam.

[0003] The invention is based on the object of specifying a busbar for electrically connecting individual cells of an electrical energy storage device and an electrical energy storage device with at least one such busbar.

[0004] The object is achieved according to the invention by a busbar having the features specified in claim 1 and by an electrical energy storage device having the features specified in claim 5.

[0005] Advantageous embodiments of the invention are the subject of the subclaims.

[0006] A busbar for electrically interconnecting individual cells of an electrical energy storage device comprises, according to the invention, a web-shaped bridge element and a plurality of flat, arc-shaped current contact elements, wherein in each case a current contact element for electrically interconnecting two adjacent individual cells is arranged and / or formed at one end of a torsion bar projecting from the bridge element, and a support edge of the current contact element arranged parallel to the longitudinal axis of the torsion bar is designed to rest on a pole contact of an individual cell, and a further support edge of the current contact element running parallel to the opposite support edge is designed to rest on a pole contact of an adjacent individual cell.

[0007] Using a busbar designed in this way, it is possible to securely connect pole contacts of adjacent individual cells to one another, in particular in a materially bonded manner, even if the pole contacts have a height difference between them. If there is a height difference between two pole contacts to be connected to one another, the current contact element can be rotated by the torsion bar on which the current contact element is arranged and / or formed. The height difference can thus be compensated for and the two pole contacts can be connected to one another in an optimally materially and electrically bonded manner by means of the current contact element without the formation of a gap. In particular, the current contact element is welded to one pole contact of each adjacent individual cells, whereby using such a busbar the weld seam quality and thus the electrical connection between the two pole contacts can be improved, i.e. optimized.In particular, a fillet weld allows for reliable welding with a defined penetration depth, regardless of the material thickness of the current contact element. Quality control of fillet welds is simplified, and welding defects, especially so-called "false friend" welds, can be largely eliminated.

[0008] By using such a busbar for the electrical interconnection of adjacent individual cells, a rejection rate can be reduced, which can also reduce the costs of manufacturing an electrical energy storage device.

[0009] Different electrical connections, both serial and parallel and combinations thereof, are also possible using the busbar.

[0010] Embodiments of the invention are explained in more detail below with reference to drawings.

[0011] Showing: Fig. 1 schematically shows a perspective view of a busbar, Fig. 2 schematically shows a perspective view of a section of a busbar with more than two current contact elements, Fig. 3 schematically shows a perspective view of a busbar in a further embodiment, Fig. 4 schematically shows a perspective view of a section with several individual cells each electrically connected by means of a busbar, Fig. 5 schematically shows a perspective view of a section with several individual cells each electrically connected by means of a busbar formed in the further embodiment, Fig. 6 schematically shows a perspective view with several individual cells, each electrically connected by means of a busbar, with height difference and Fig. 7 schematically shows a perspective view according to Fig. 6 after welding the current contact elements of the busbar in the further embodiment.

[0012] Corresponding parts are provided with the same reference numerals in all figures.

[0013] Fig. 1 shows a perspective view of a busbar 1 for electrically connecting adjacent, in Fig. 4 to 7 shown individual cells 2 of an electrical energy storage device, in particular for a vehicle which is designed as an electric vehicle, as a hybrid vehicle or as a vehicle powered by fuel cells.

[0014] The Fig. 1, the busbar 1 shown has two current contact elements 1.1, whereas in Fig. 2 shows a perspective view of a section of a busbar 1 with more than two such current contact elements 1.1.

[0015] In general, it is known that in a welding-based joining, in particular by laser welding, of two components by means of a third component, a tolerance resulting from tolerances in the production of the components and their positioning, for example in Fig. 6 can lead to the formation of a gap, in particular between one of the two components and the third component. Process-reliable welding is therefore difficult or even impossible if a height difference δ exists. For example, such a height difference δ occurs in pole contacts 2.1 of adjacent individual cells 2, so that electrical interconnection of the pole contacts 2.1, which have a height difference δ from one another, is possible to a limited extent and, for example, only a simple connection of, for example, two pole contacts 2.1 can be produced with the greatest possible process reliability.

[0016] In order to compensate for such a height difference δ with respect to a connection and thus an electrical interconnection of at least two pole contacts 2.1 of adjacent individual cells 2, the busbar 1 is designed as described below.

[0017] The Fig. The busbar 1 shown in Figure 1 has two current contact elements 1.1, wherein a current contact element 1.1 is arranged at one end of a torsion bar 1.2, wherein a respective torsion bar 1.2 protrudes from a web-shaped bridge element 1.3 of the busbar 1. The current contact elements 1.1, the torsion bars 1.2, and the bridge element 1.3 are electrically conductive, so that a pole contact 2.1 of an individual cell 2 can be electrically connected to a pole contact 2.1 of an adjacent individual cell 2.

[0018] The current contact elements 1.1 of the busbar 1 have a material thickness t of at least 0.1 mm and at most 4.0 mm and are arcuate, with each current contact element 1.1 having two support edges 1.1.1, 1.1.2. The support edges 1.1.1, 1.1.2 run parallel to the longitudinal axis of the torsion bar 1.2 and are opposite one another. The current contact element 1.1 is designed such that the two support edges 1.1.1, 1.1.2 are offset from one another by a height Δh. The height Δh is at least 0.1 mm and at most 8.5 mm.

[0019] According to a Fig. 1 and Fig. In the embodiment of the busbar 1 shown in Figure 2, the respective current contact element 1.1 has a square arched shape.

[0020] A length I T of the respective torsion bar 1.2 of the busbar 1 is, for example, at least 0.2 mm.

[0021] The web-shaped bridge element 1.3 of the busbar 1 has a length not shown in detail, so that by means of one of the two current contact elements 1.1 a pole contact 2.1 of an individual cell 2 can be electrically connected to a pole contact 2.1 of an adjacent individual cell 2.

[0022] Fig. Figure 3 shows a perspective view of a busbar 1 in a further embodiment, wherein the busbar 1 has two current contact elements 1.1, which are formed in a rounded arc and each have two support edges 1.1.1, 1.1.2. The dimensions of the busbar 1 in the further embodiment correspond essentially to those in Fig. 1 shown dimensions.

[0023] Fig. Figure 4 shows four individual cells 2 that are electrically interconnected by means of a busbar 1, with the current contact elements 1.1 being shown in an unattached state with respect to the pole contacts 2.1 of the individual cells 2. For example, these four individual cells 2 form a cell assembly for an electrical energy storage device.

[0024] According to the Fig. In the embodiment shown in Figure 4, the individual cells 2 with their pole contacts 2.1 do not have any height differences δ to be compensated.

[0025] In Fig. 5 shows four individual cells 2 with a busbar 1 in the further embodiment.

[0026] Fig. 6 shows a perspective view with several individual cells 2, each electrically connected by means of a busbar 1, with a height difference δ, wherein a more or less pronounced height difference δ is present between all adjacently arranged individual cells 2.

[0027] In order to compensate for the respective height difference δ between individual cells 2 to be electrically connected by means of a current contact element 1.1, a hold-down force F is exerted on the current contact element 1.1. The hold-down force F causes the current contact element 1.1 to rotate about a rotation axis D shown in dashed lines, which runs along the longitudinal axis of the torsion bar 1.2. This rotation of the current contact element 1.1 results in tolerance compensation, so that one support edge 1.1.1 rests on a pole contact 2.1 of an individual cell 2 and the other support edge 1.1.2 rests on a pole contact 2.1 of an adjacent individual cell 2, so that the two pole contacts 2.1 are electrically connected to one another.

[0028] Because both contact edges 1.1.1, 1.1.2 rest on a pole contact 2.1 each, the current contact element 1.1 of the busbar 1 can be reliably welded to the respective pole contact 2.1, as shown in Fig. 7. In particular, the contact edges 1.1.1, 1.1.2 of the respective current contact element 1.1 of the busbar 1 are integrally connected to a pole contact 2.1 of adjacent individual cells 2 by means of weld seams S designed as fillet welds and thus electrically connected.

[0029] According to the Fig. In the embodiment shown in Fig. 7, two adjacently arranged individual cells 2 are electrically connected in parallel with one another, wherein the pairs of individual cells connected in parallel are electrically connected in series with one another by means of the busbar 1.

[0030] Because the contact edges 1.1.1, 1.1.2 of the respective current contact element 1.1 are recognizable, in particular automatically recognizable, the weld seams S can be created at a precise position. The weld seams S, designed as fillet welds, can be created using a linear laser-based weld seam S and / or by superimposed lateral laser beam movement, using so-called wobbling, and optionally with power modulation.

[0031] By bonding the respective current contact element 1.1 to the two pole contacts 2.1 using fillet welds, the weld depth is independent of the material thickness t of the current contact elements 1.1 compared to so-called I-welds. With such an I-weld, the penetration depth into the pole contacts 2.1 becomes more uncontrollable with increasing material thickness t of the current contact element 1.1.

[0032] By means of a busbar 1 designed in this way and by means of the fillet welds as weld seams S, a change of material and a change of the material thickness t is possible.

[0033] Such a bonded joint is applicable for the production of metallic joints, particularly for aluminum and copper materials, as well as their mixed compounds. Such a bonded joint exhibits comparatively high strength. QUOTES CONTAINED IN THE DESCRIPTION

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

[0000] DE 10 2021 005 574 A1

[0002]

Claims

[1] Busbar (1) for electrically connecting individual cells (2) of an electrical energy storage device, characterized by a web-shaped bridge element (1.3) and a plurality of flat, arc-shaped current contact elements (1.1), wherein in each case a current contact element (1.1) is arranged and / or formed for the electrical connection of two adjacent individual cells (2) at one end of a torsion bar (1.2) projecting from the bridge element (1.3), and a support edge (1.1.1) of the current contact element (1.1), arranged parallel to the longitudinal axis of the torsion bar (1.2), is designed to rest on a pole contact (2.1) of an individual cell (2), and a further support edge (1.1.2) of the current contact element (1.1), running parallel to the opposite support edge (1.1.1), is designed to rest on a pole contact (2.1) of an adjacent individual cell (2). [2] Busbar (1) according to claim 1, characterized bythat the support edges (1.1.1, 1.1.2) of a current contact element (1.1) are formed with a height offset (Δh) from one another. [3] Busbar (1) according to claim 1 or 2, characterized by that the height offset (Δh) of the support edges (1.1.1, 1.1.2) of a current contact element (1.1) is between 0 mm and 8.5 mm. [4] Busbar (1) according to one of the preceding claims, characterized by that a material thickness (t) of the current contact element (1.1) is at least 0.1 mm and at most 8.5 mm and a length (I T ) of the torsion bar (1.2) is at least 0.2 mm. [5] Electrical energy storage device with a plurality of individual cells (2), wherein at least two adjacent individual cells (2) are electrically connected by means of a busbar (1) designed according to one of claims 1 to 4. [6] Electrical energy storage device according to claim 5, characterized bythat the two contact edges (1.1.1, 1.1.2) of a respective current contact element (1.1) are integrally connected to a pole contact (2.1) of adjacent individual cells (2).

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