Device for electrically contacting battery cells

Abstract

The invention relates to a device for electrically contacting multiple battery cells (1) which are arranged in rows (4a-g) along a main direction (3) with respect to the longitudinal axis of the device and which have contact pieces (2) that are positioned on a contact plane without crossing one another, follow one another in the main direction, and have series conductors (7) for connecting the opposite cell poles (5, 6) of exactly two battery cells (1) in each case and parallel conductors (8) for connecting said series conductors (7). In order to provide a device which provides a higher capacitance while having the same weight and installation space despite low line losses, it is proposed that the series conductors (7) connect cell poles (5) of one row (4a) to cell poles (6) of at least two other rows (4e, 4f).

Description

[0001] Device for electrically contacting battery cells

[0002] Technical area

[0003] The invention relates to a device for electrically contacting a plurality of battery cells arranged in rows with respect to their longitudinal axis along a main direction, with contact pieces arranged in a contact plane without crossing and following one another in the main direction, which have serial conductors for connecting the opposing cell poles of exactly two battery cells each and parallel conductors for connecting these serial conductors.

[0004] State of the art

[0005] CN114122599A shows a device for electrically contacting battery cells. These battery cells are arranged in rows along a main direction and are connected via several contact pieces, both in series and in parallel. A disadvantage of this device, however, is that the capacity and thus the drawable current are limited.

[0006] From US20210328309A1, it is known to connect a plurality of battery cells arranged in rows along a main direction both in parallel and in series, with several battery cells of a group being connected to each other via a parallel conductor. This parallel conductor is connected via a series conductor to the parallel conductor connecting several battery cells of an adjacent group. However, this has the disadvantage that the available current is limited by the cross-section of the series conductor, so that either correspondingly large cross-sections must be provided or localized heating of the series conductors must be accepted. This means that either an increase in weight or corresponding line losses occur. Description of the invention

[0007] The invention is therefore based on the object of proposing a device for electrically contacting battery cells which provides a higher capacity despite low line losses while maintaining the same weight and installation space.

[0008] The invention achieves this objective by having serial conductors connect cell terminals of one row to cell terminals of at least two additional rows. These features, in conjunction with contacting exactly two battery cells via a serial conductor, allow more rows to be contacted in parallel while maintaining the same number and arrangement of battery cells, without causing an increased current flow through individual serial conductors. To improve manufacturing conditions in this context, the serial conductors and parallel conductors can be formed as a single piece. For example, the serial conductors and parallel conductors can be limbs of a common, single-piece contact piece, which is preferably punched or cut out of an electrically conductive metal.To connect exactly two battery cells, the serial conductors can form contact points at their end sections, each of which can be connected to an externally directed electrical cell pole. For example, one contact point can be connected to the cell pole arranged centrally on the cover side of a battery cell, whereas the other contact point is connected to the cell casing, which is typically electrically connected to the opposite cell pole. Since the cell casing is usually bent over onto the cover surface of the battery cell, a device according to the invention can run in a single contact plane. The cross-free arrangement of the contact pieces according to the invention, i.e. the avoidance of crossing conductors, preferably results in only one electrically active layer, so that electrical insulation, as would be the case with several superimposed layers, can be omitted.

[0009] To reduce the length of the serial conductors and thus further reduce line losses, it is proposed that the serial conductors run at least partially obliquely to the main direction. Such an arrangement facilitates the shunting of the conductors in a contact plane and, in particular, enables the mutual engagement of the end sections of the serial conductors containing the contact points. In a preferred embodiment, the end sections of the serial conductors run obliquely to the main direction, with the angle enclosed between the end sections and the main direction preferably being between 15 and 45 degrees, particularly preferably 30 degrees. A group of parallel conductors can run perpendicular to the main direction.

[0010] To keep the voltage levels of neighboring battery cells low to prevent arcing, the battery cells of at least three consecutive rows can be connected in parallel using series and parallel conductors. This measure ensures that the voltage level between neighboring battery cells increases by no more than the voltage of a single cell, thus preventing larger voltage differences.

[0011] To prevent uneven loading of the individual battery cells due to varying conduction losses, it is proposed that the number of rows spanned by two consecutive series conductors in the main direction be constant. This not only promotes a symmetrical arrangement of the contact pieces, but also compensates for any length differences between the serial conductors within a contact piece in the subsequent contact piece in the main direction, which further reduces the formation of cross currents.

[0012] Production effort and thus production costs can be reduced by arranging two consecutive contact pieces in the main direction in a mirrored manner around a center plane running perpendicular to the contact plane in the main direction. This allows identically manufactured contact pieces to be used, with consecutive contact pieces in the main direction arranged at a 180° angle to each other around an axis running in the main direction. To improve electrical contact during cell respiration and vibration-induced movements of the battery cells, it is proposed that the contact pieces be embedded in a laminate.This not only determines the relative position of the contact pieces and improves structural integrity, but also creates the basis for the contact pieces to follow the individual movements of the battery cells due to bending and twisting of the laminate without mechanically overloading the contact points or even tearing off the end sections of the serial conductors. Furthermore, the laminate can be electrically insulating, eliminating the need for separate insulation between the contact pieces. The end sections of the serial conductors can be laminate-free and thus electrically conductive.

[0013] A high energy density can be achieved in a battery module with the inventive device for battery cell contacting by arranging the circular-cylindrical battery cells in a hexagonal, densely packed configuration with respect to their cross-section. This allows the volume of the battery cells to be reduced.

[0014] Particularly secure contact between the battery cells can be achieved if the serial conductors have a fuse with a reduced cross-section at one of their end sections. If a voltage overload occurs in the device according to the invention, the current flow is interrupted by the melting of the fuse, which in turn prevents damage to the battery cells or a thermal chain reaction. The fuses can be designed in a meandering shape for reliable melting at a given current strength.

[0015] Reliable cell terminal contact is achieved by the fact that the end sections of the serial conductors protrude from the contact plane toward the battery cells. This allows the contact points protruding from the contact plane at the end sections of the serial conductors to be positioned against the cell terminals with a spring force determined by the shape.

[0016] Brief description of the invention

[0017] The drawing shows an example of the subject matter of the invention.

[0018] Fig. 1 is a schematic plan view of a device according to the invention with battery cells indicated by dash-dotted lines,

[0019] Fig. 2 is a detailed view of Fig. 1 on a larger scale and

[0020] Fig. 3 is a section along the line lll-lll of Fig. 2 on an even larger scale.

[0021] Ways to implement the invention

[0022] A device for electrically contacting battery cells 1 comprises a plurality of contact pieces 2 arranged consecutively in a main direction 3. The battery cells 1 are arranged parallel with respect to their longitudinal axes and in rows 4a-d along the main direction 3. The contact pieces 2 extend in a contact plane, with the contact pieces 2 being arranged without crossings.

[0023] For the electrical contacting of the opposing cell poles 5, 6 of exactly two battery cells 1, serial conductors 7 are provided, which are indicated by broad, dash-dotted lines in Fig. 2 for ease of illustration. The serial conductors 7 are connected to each other via parallel conductors 8.

[0024] As can be seen in particular from Fig. 2, the serial conductors 7 connect cell poles 5 of a row 4a with cell poles 6 of at least two further rows 4e, 4f.

[0025] To facilitate the routing of the conductors 7, 8, the serial conductors 7 can run at least partially obliquely to the main direction 3, preferably at an angle of between 20 and 40 degrees, preferably 30 degrees. At least one group of parallel conductors 8 can run transversely to the main direction 3. According to the features of the invention, the battery cells 1 of successive rows 4a-c or 4d-f can be connected in parallel.

[0026] In the illustrated embodiment, the number of rows 4a-g spanned by two consecutive serial conductors 7 in the main direction is constant and amounts to 7 rows.

[0027] As can be seen in particular from Fig. 1, the contact pieces 2 arranged successively in the main direction 3 are of identical design and arranged alternately rotated by 180 degrees relative to one another with respect to an axis extending in the main direction 3. In other words, two contact pieces 2 arranged successively in the main direction 3 are arranged mirrored about a center plane 9 extending transversely to the contact plane in the main direction 3.

[0028] As shown in Fig. 3, the individual contact pieces 2 can form the core of a laminate surrounded by two foil layers 10. Such a foil layer 10 is also indicated in Fig. 1 by a broken, dashed line. The end sections of the serial conductors 7, not further designated, form contact points 11 for the cell poles 5, 6, wherein the contact points 11 are designed without a laminate. To protect the individual battery cells 1, an end section of the serial conductors 7 adjacent to the contact points 11 can be provided with a meander-shaped fuse 12 which has a reduced cross-section compared to the remaining end section. The end sections of the serial conductors 7 can also protrude from the contact plane in the direction of the battery cells 1.

[0029] For reasons of clarity, not all battery cells 1, cell poles 5, 6, serial conductors 7, parallel conductors s, contact points 11 and fuses 12 are provided with reference symbols in the drawing.

[0030] As can be seen from Figs. 1 and 2, the battery cells 1 are circular-cylindrical in shape and arranged in a hexagonal, densely packed cross-section. This means that each internal battery cell 1 is surrounded by six additional battery cells 1.

Claims

Patent claims 1. Device for electrically contacting a plurality of battery cells (1) arranged in rows (4a-g) with respect to their longitudinal axis along a main direction (3), with contact pieces (2) arranged without crossing in a contact plane and following one another in the main direction, which have serial conductors (7) for connecting the opposing cell poles (5, 6) of exactly two battery cells (1) each and parallel conductors (8) for connecting these serial conductors (7), characterized in that the serial conductors (7) connect cell poles (5) of one row (4a) to cell poles (6) of at least two further rows (4e, 4f).

2. Device according to claim 1, characterized in that the serial conductors (7) run at least in sections obliquely to the main direction (3).

3. Device according to one of claims 1 or 2, characterized in that the battery cells (1) of at least three consecutive rows (4a, 4b, 4c) are connected in parallel by means of serial and parallel conductors (7, 8).

4. Device according to one of claims 1 to 3, characterized in that the number of rows (4a-g) spanned by two serial conductors (7) following one another in the main direction (3) is constant.

5. Device according to one of claims 1 to 4, characterized in that two contact pieces (2) following one another in the main direction (3) are arranged mirrored about a central plane (9) extending transversely to the contact plane in the main direction (3).

6. Device according to one of claims 1 to 5, characterized in that the contact pieces (2) are embedded in a laminate.

7. Device according to one of claims 1 to 6, characterized in that the circular-cylindrical battery cells (1) are arranged hexagonally densely packed with respect to their cross section.

8. Device according to one of claims 1 to 7, characterized in that the serial conductors (7) have a fuse (12) with a reduced cross-section at one of their end sections.

9. Device according to one of claims 1 to 8, characterized in that the end sections of the serial conductors (7) protrude from the contact plane in the direction of the battery cells (1).

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