ELECTRIC ENERGY STORAGE FOR A MOTOR VEHICLE

Abstract

An electrical energy storage device (30) for a motor vehicle (50) is provided, wherein the electrical energy storage device (30) comprises battery cells (1), each having a housing (3, 4) and a cell contact (2) formed in or on the housing (3, 4), the cell contact (2) forming a first electrical pole and the housing (3, 4) forming a second electrical pole. The electrical energy storage device (30) comprises a cell contacting system for establishing an electrical connection between the battery cells (1), wherein the cell contacting system comprises parallel electrical connectors (20A; 20B; 20C; 20D) that each electrically connect two lateral surfaces (4) of the housings (3, 4) of two of the battery cells (1).

Description

[0001] The present disclosure relates to an electrical energy storage device for a motor vehicle, and / or a motor vehicle comprising the electrical energy storage device.

[0002] Modern high-voltage batteries and traction batteries for motor vehicles are increasingly manufactured in cell-to-pack or cell-to-open-body configurations. Instead of being divided into clearly separated modules, the battery housing is completely filled with cells. Cooling lines, the cell contact system, and other components also provide additional stiffening. Adhesives are also playing an increasing role. The battery cells are also increasingly playing a key role in structural strength. The remaining cavities are often filled with foam, for example, to increase mechanical stability and for other reasons.

[0003] In conventional high-voltage batteries, transverse or longitudinal stiffeners are typically used in the form of profiles. In cell-to-pack configurations, support structures in the high-voltage battery are increasingly eliminated. For example, a main force path must connect the battery cover to the battery base. Especially in battery cells designed as round cells, there is very little space for these connections, since the battery cells themselves are largely covered on the front side by the cell contact system, which cannot be used for power transmission.

[0004] This prevents the cell contact system from being subjected to high mechanical stress, as it also carries a safety load. A detachment of a connection between the cell contact system and a battery cell leads to overloading of the parallel battery cells or to arcing, which can trigger a thermal event. At the same time, the cell contact system blocks the connection surface of adhesives or foam on the front side of the battery cell to the battery cell or other structures that must transmit the load. This prevents a continuous connection between the battery cover and base.

[0005] Furthermore, large stiffening structures reduce the potential energy density and essentially create battery cell modules again.

[0006] WO 2021 / 042141 A1 describes a device with a plurality of battery cells arranged parallel to one another with respect to a joining axis, and a contact plate arranged between the battery cells with a plurality of recesses for circumferentially enclosing the battery cells. The contact plate has a plurality of contact plate legs that enclose the battery cells, leaving a recess for a circumferential section, and are connected to one another at intersection points.

[0007] CN 211208498 U describes an elastic battery parallel connection plate comprising a U-shaped outer contour with a bottom surface made of metal materials and two side edges made of metal materials integrally connected to the two longitudinal ends of the bottom surface. A plurality of arcuate bending parts are arranged along the longitudinal direction of each side edge, the opening directions of the arcuate bending parts being opposite at the two side edges, and the arcuate bending parts are integrally stamped to form conductive elastic plates that protrude inward.

[0008] WO 2016 / 053425 A1 describes a battery module containing a plurality of lithium-ion battery cells arranged in a battery module package. Each of the plurality of lithium-ion battery cells is individually held in place within the battery module package by a retention medium. The retention medium covers a substantial portion of the surface of each of the plurality of lithium-ion battery cells and prevents each of the plurality of lithium-ion battery cells from expanding during operation of the battery module.

[0009] DE 10 2019 208 949 A1 describes a battery module with a plurality of battery cells, each having a battery cell housing in which electrochemical components of the respective battery cell are accommodated. The battery cells furthermore each have a positive voltage tap and a negative voltage tap, wherein the negative voltage tap of a battery cell is formed by the respective battery cell housing. The battery module furthermore has a parallel connection element which is designed to electrically connect the negative voltage taps of the individual battery cells in parallel with one another, wherein the parallel connection element has openings in which one of the battery cells is accommodated in such a way that the respective battery cell housing is electrically conductively connected to the parallel connection element.

[0010] EP 4 080 672 A1 describes a battery pack including a housing, a plurality of cylindrical battery cells arranged in the housing, and a current interruption device arranged in the housing to connect the plurality of cylindrical battery cells and comprising a bimetal portion. The current interruption device has a fixed end contacting an electrode terminal of the cylindrical battery cell, a free end contacting an electrode terminal of the surrounding cylindrical battery cell, and a flexible element configured to elastically urge the free end toward the surrounding cylindrical battery cell.

[0011] Against the background of this prior art, the object of the present disclosure is to provide a device which is each suitable for enriching the prior art.

[0012] The problem is solved by the features of the independent claims. The subordinate claims and the dependent claims each contain optional developments of the disclosure.

[0013] The task is then solved by an electrical energy storage device, e.g. a traction battery and / or high-voltage battery, for a motor vehicle.

[0014] The electrical energy storage device comprises (optionally cylindrical) battery cells, each of which has a housing and a cell contact formed in or on the housing. The cell contact forms a first electrical pole, and the housing forms a second electrical pole. The first electrical pole can be a positive pole and the second electrical pole can be a negative pole (or vice versa).

[0015] The electrical energy storage device comprises a cell contact system for establishing an electrical connection between the battery cells, e.g., an electrical series connection of the battery cells.

[0016] The cell contact system has electrical parallel connectors that electrically connect two outer surfaces of the housings of two of the battery cells, optionally directly.

[0017] The electrical parallel connectors can be designed to equalize the voltages of the battery cells. The electrical parallel connectors can form a parallel connection between the battery cells, via which the battery cells can equalize or balance their electrical voltages, e.g., so that all battery cells have the same or at least similar electrical voltages. For example, a battery cell with the highest electrical voltage in this parallel connection can discharge and thereby charge a battery cell with the lowest electrical voltage.

[0018] The electrical energy storage device described above offers a number of advantages. Among other things, it provides a cell contact system that is not located entirely on the end faces of the battery cells, but at least partially utilizes the free spaces between the battery cells. This advantageously creates space for support structures (e.g., transverse or longitudinal stiffeners) or connection surfaces for adhesives and / or foam, which contribute to the structural strength of the electrical energy storage device.

[0019] Possible further developments of the device described above are explained in detail below.

[0020] The battery cells can be cylindrical, e.g., round cells. Other battery cells are also conceivable, e.g., prismatic battery cells.

[0021] The battery cells can be low-voltage battery cells, e.g., 4.2 V, 3.8 V, or 3 V. The battery cells can be lithium-ion batteries, e.g., lithium iron phosphate batteries, and / or sodium-ion batteries.

[0022] The electrical energy storage device can comprise, for example, 50, 100, 1000 or 2000 battery cells, which can be electrically connected in series (and parallel) using the cell contact system.

[0023] The electrical parallel connectors can each be designed as a clamp and / or spring element. This allows the electrical parallel connectors to advantageously engage the casing surfaces with a respective contact force.

[0024] The electrical parallel connectors can be mechanically pre-tensioned between the two battery cells and / or clamped between the two casing surfaces.

[0025] The electrical parallel connectors can each have two legs, on each of which a contact surface for one of the two jacket surfaces can be formed.

[0026] The two legs can be designed mirror-symmetrically to a longitudinal axis of the respective electrical parallel connector.

[0027] The two legs can each have a shape that is at least partially curved (e.g. concave) so that the respective contact surface is at least partially shaped to match one of the two lateral surfaces.

[0028] The electrical parallel connectors may each have an end structure that connects the two legs together.

[0029] The two legs can each have a free end. The two legs can each have a further end opposite the free end (e.g., in the longitudinal direction of the two legs) and at which the two legs are connected to each other via the end structure.

[0030] The end structure can be arrow-shaped and / or barbed. This advantageously allows the electrical parallel connectors to be correctly positioned and, if possible, prevents removal of the electrical parallel connectors.

[0031] The end structure may be configured such that an insertion direction for inserting the respective electrical parallel connector between the two of the battery cells extends only in a longitudinal direction or in a transverse direction of the two of the battery cells.

[0032] The electrical parallel connectors can each have a wave-shaped configuration, e.g., a longitudinal configuration. Due to the wave-shaped configuration, e.g., a longitudinal configuration, concave contact surfaces can be formed for the respective connection of one of the two lateral surfaces of the two battery cells.

[0033] It is also conceivable that the wave-shaped configuration, e.g., longitudinally, can create concave contact surfaces for the respective contact of one of several lateral surfaces of several (optionally more than two) battery cells. The electrical parallel connectors can each be designed as a strut, which can be arranged, for example, between two cell rows, each of which is formed from several of the battery cells.

[0034] The electrical parallel connectors configured as struts can each have, in the longitudinal direction (e.g., of the respective strut), a first longitudinal side surface with a first set of concave contact surfaces and a second longitudinal side surface with a second set of concave contact surfaces. The second longitudinal side surface can be opposite the first longitudinal side surface. The first set of concave contact surfaces and the second set of concave contact surfaces can be offset from one another in the longitudinal direction (e.g., of the respective strut). The electrical parallel connectors configured as struts can advantageously have a stiffening effect on the overall structure and the arrangement of the battery cells or the electrical energy storage device.

[0035] Spring lamellae can be formed, embedded, injected, and / or cast on or in the concave contact surfaces. The spring lamellae can be at least partially embedded, injected, and / or cast in a non-electrically conductive matrix or a non-electrically conductive material, e.g., plastic. Such a matrix can advantageously ensure a positive fit of the electrical parallel connectors with the lateral surfaces and thus the most precise positioning of the electrical parallel connectors.

[0036] It is also conceivable for the electrical parallel connectors to be formed from a (e.g., thin) spring steel and / or spring wire, e.g., similar to a hair clip. This advantageously creates an additional or localized force connection at the cell walls. Furthermore, the insertion of the electrical parallel connector is advantageously enabled by a force-induced cross-sectional reduction.

[0037] The electrical parallel connectors can be designed for low-resistance electrical connections, e.g., in a range of 1 to 100 ohms.

[0038] The electrical parallel connectors can each comprise multiple metal layers and / or be designed as bimetal. This advantageously further increases the contact force with which the electrical parallel connectors rest against a respective jacket surface during thermal stress (e.g., due to heat generation during battery cell operation) and counteracts higher contact resistance. This can be particularly advantageous during a thermal event in an individual battery cell, for example, since a current-carrying parallel current path may be required for fuse triggering in the serial path.

[0039] The electrical parallel connectors can be made at least partially of carbon, soot, and / or carbon nanotubes and / or contain metal particles (e.g., silver, aluminum, and / or copper). The electrical parallel connectors can, for example, consist of material filled with carbon, soot, carbon nanotubes, and / or metal particles.

[0040] The electrical parallel connectors can be formed at least partially from a thermally conductive material. This can be advantageously used for heat dissipation in the event of propagation, e.g., when a thermal event occurs in one of the battery cells.

[0041] The cell contact system can comprise electrical series connectors, each of which electrically connects the cell contact of one of the battery cells to a housing end face of another of the battery cells surrounding the cell contact. The electrical series connectors can, for example, form a main current path that connects and / or encompasses all of the battery cells. The electrical series connectors can also be referred to as (electrical) serial connectors.

[0042] The electrical series connectors can each have a joint and / or fuse, which can be configured, for example, as a tapered portion of the respective electrical series connector. The joint and / or fuse can be configured to melt and thereby disconnect the respective electrical series connector if and / or as soon as a thermal event occurs in one of the two battery cells connected by the respective electrical series connector.

[0043] The electrical parallel connectors can be designed, for example, with regard to their thickness, width and / or material, such that the electrical parallel connectors remain intact if the joint and / or fuse of one of the electrical series connectors melts or has melted (and the main current path is thereby interrupted).

[0044] The battery cells can be arranged next to one another in the same direction (e.g. in several cell rows), e.g. such that the cell contacts of the battery cells are arranged on the same side (e.g. on a top side of the arrangement of battery cells).

[0045] The electrical energy storage device may comprise a storage housing in which the battery cells and the cell contact system (optionally completely) are arranged.

[0046] The battery cells can be arranged in a cell-to-pack configuration (or cell-to-open-body configuration) and / or not in battery modules.

[0047] It is conceivable that one or more support structures are provided within the storage housing on the end faces of the battery cells and / or adjacent to the electrical series connectors. Alternatively, or additionally, at least one support structure can be provided, which is arranged within the storage housing and connects a storage cover and a storage base of the storage housing.

[0048] The above description can be summarized in other words and in a possible more concrete embodiment of the disclosure as described below, whereby the following description is not to be interpreted as limiting the disclosure.

[0049] Approximately half of the cell contact system can consist of (electrical) parallel connectors. Since the respective cell casing itself can represent a terminal in cylindrical battery cells (or round cells), it can be used as a connecting surface for an electrical parallel connection. The connection (i.e., the electrical parallel connector) can be established via a conductive clamp or spring, for example, a preloaded one.

[0050] According to one embodiment, the electrical parallel connector can be formed from multiple metal layers, e.g., different metals or a bimetal. This allows the contact force to be further increased under thermal stress and counteracts higher contact resistance.

[0051] According to one embodiment, the electrical parallel connector can be inserted laterally, e.g., with a barb system.

[0052] According to one embodiment, the electrical parallel connector can be represented by spring lamellas, wherein these spring lamellas can be embedded, injected, and / or cast in a non-conductive matrix (e.g., plastic). This matrix can ensure the positive locking and positioning between the battery cells. The matrix can be designed, for example, to contain multiple parallel connectors, thus, for example, having a stiffening effect on the overall structure.

[0053] According to one embodiment, the electrical parallel connector may be made of material filled with carbon, carbon black, carbon nanotubes or similar.

[0054] According to one embodiment, the electrical parallel connector can be made of a material filled with metal particles. Silver, aluminum, and copper are particularly advantageous. In this embodiment, the electrically conductive connection can also be advantageously used for good heat transfer, e.g., for heat dissipation in the case of propagation.

[0055] Furthermore, a motor vehicle is provided, wherein the motor vehicle comprises the electrical energy storage device described above.

[0056] The motor vehicle may be a passenger car, in particular an automobile, or a commercial vehicle, such as a truck.

[0057] The motor vehicle can be an electrically powered, optionally drivable, motor vehicle.

[0058] The electrical energy storage device can be designed as a traction battery and / or high-voltage battery of the motor vehicle.

[0059] The electrical energy storage device can be arranged in a crash-protected installation space of the motor vehicle. The electrical energy storage device can be located in or on the underbody of the motor vehicle, optionally between the front wheels. Furthermore, alternative locations for the electrical energy storage device in the motor vehicle are conceivable, e.g., if the electrical energy storage device has fire-resistant compositions (e.g., lithium ferrophosphate batteries).

[0060] What has been described above with reference to electrical energy storage also applies analogously to motor vehicles and vice versa.

[0061] Furthermore, a method for producing an electrical energy storage device for a motor vehicle, e.g. the electrical energy storage device described above, is provided.

[0062] The method comprises providing (optionally cylindrical) battery cells and a cell contacting system, e.g., the battery cells and the cell contacting system described above.

[0063] The method comprises arranging the battery cells, e.g., in several rows of cells arranged next to one another.

[0064] The method comprises attaching the cell contacting system to the arranged battery cells to establish an electrical connection between the battery cells.

[0065] The attachment comprises arranging, e.g., plugging in, electrical parallel connectors of the cell contact system such that two lateral surfaces of the housings of two of the battery cells are and / or are electrically connected.

[0066] The attachment may comprise arranging electrical series connectors of the cell contacting system, e.g., such that a cell contact of one of the battery cells and an end face of the housing surrounding the cell contact of another of the battery cells are and / or are electrically connected.

[0067] What has been described above with reference to the electrical energy storage system and motor vehicle also applies analogously to the process and vice versa.

[0068] Below are optional embodiments with reference to the Fig. 1 and Fig. 2 described. Fig. 1 shows schematically a motor vehicle according to the disclosure with an electrical energy storage device; and Fig. 2 schematically shows components of the electrical energy storage device, including several embodiments of an electrical parallel connector of a cell contacting system.

[0069] Fig. 1 shows only a schematic view of the motor vehicle 50, which includes the electrical energy storage device 30. The electrical energy storage device 30 serves as a traction storage device for electrically propelling the motor vehicle 50.

[0070] Fig. 2 shows only schematic components of the electrical energy storage device 30.

[0071] Thus, the electrical energy storage device 30 comprises cylindrical battery cells 1 (or round cells), each having a housing and a cell contact 2 formed in or on the housing, wherein the cell contact 2 forms a first electrical pole and the housing forms a second electrical pole. The respective housing of the battery cells 1 can consist, among other things, of a lateral surface 4 and an end face 3 surrounding the cell contact 2. Other battery cell shapes, e.g., prismatic battery cells, are also conceivable.

[0072] The battery cells 1 can be arranged side by side in the same direction, e.g., such that the cell contacts 2 of the battery cells 1 are arranged on the same side (e.g., on a top side of the arrangement of battery cells 1). Furthermore, the battery cells can be arranged side by side in cell rows, e.g., forming the most compact arrangement possible.

[0073] The battery cells 1 can be held or fastened within a storage housing of the electrical energy storage device 30 by means of holders 5 in which the battery cells 1, e.g. one of the cell rows each, are inserted.

[0074] In the Fig. For the sake of simplicity, only three battery cells 1 are shown in Fig. 2, which are inserted into two holders 5. The complete electrical energy storage device 30 can comprise a plurality of battery cells 1, e.g., more than 100 battery cells 1, arranged side by side in several cell rows.

[0075] The electrical energy storage device 30 comprises a cell contacting system for establishing an electrical connection between the battery cells 1.

[0076] The cell contact system has electrical series connectors 10 for electrical series connection of the battery cells 1, which, for example, are designed according to the Fig. 2. The electrical series connectors 10 can, for example, each electrically connect the cell contact 2 of one of the battery cells 1 and an end face 3 of the housing surrounding the cell contact 2 of another of the battery cells 1.

[0077] By means of the electrical series connectors 10, all battery cells 1 of the electrical energy storage device 30 can be electrically connected in series. Accordingly, the electrical energy storage device 30 can comprise, for example, X battery cells 1 and X-1 electrical series connectors 10, where X can correspond to a natural number greater than 1.

[0078] The cell contacting system has electrical parallel connectors 20A, 20B, 20C, 20D, which each electrically connect two lateral surfaces 4 of the housings of two adjacently arranged battery cells 1.

[0079] The electrical parallel connectors 20A, 20B, 20C, 20D can, for example, each have multiple metal layers and / or be formed as bimetal. It is also conceivable for the electrical parallel connectors 20A, 20B, 20C, 20D to consist at least partially of carbon, carbon black, and / or carbon nanotubes and / or to comprise metal particles.

[0080] Fig. 2 shows four possible embodiments of such an electrical parallel connector 20A, 20B, 20C, 20D, which are each designed as a clamp and / or spring element or, in the installed state, are mechanically prestressed between two adjacently arranged battery cells 1 and / or are clamped between two lateral surfaces 4.

[0081] The two (middle) embodiments of the electrical parallel connector 20B, 20C each have two legs 22B, 22C, on each of which a contact surface 21B, 21C is formed for one of the two lateral surfaces 4. The two legs 22B, 22C are each formed mirror-symmetrically to a longitudinal axis of the respective electrical parallel connector 20B, 20C. The legs 22B of the electrical parallel connector 20B further each have a curved or concave shape, at least in sections, such that the respective contact surface 21B is formed at least in sections to match the shape of one of the two lateral surfaces 4.

[0082] The electrical parallel connectors 20B, 20C each have an end structure 23B, 23C that connects the two legs 22B, 22C to one another. The end structure 23B, 23C can be configured such that a plug-in direction for plugging in the respective electrical parallel connector 20B, 20C between the two battery cells 1 can run only in a longitudinal direction or in a transverse direction of the two battery cells 1. The end structure 23C is furthermore arrow-shaped and / or designed as a barb, so that, for example, pulling out the electrical parallel connector 20C counter to the plug-in direction can be prevented as far as possible when it is in the installed state.

[0083] The respective insertion direction of the electrical parallel connectors 20B, 20C is indicated by a respective arrow in Fig. 2. Thus, the electrical parallel connector 20B can be configured such that it can be inserted (only) from above or in the longitudinal direction of the battery cells 1 between two battery cells 1. In comparison, the electrical parallel connector 20C can be configured such that it can be inserted (only) from the side or in the transverse direction of the battery cells 1 between two battery cells 1.

[0084] The two (outer) embodiments of the electrical parallel connector 20A, 20D each have a wave-shaped profile, e.g., a longitudinal profile, wherein the wave-shaped profile forms concave contact surfaces 21A, 21D for the respective contact of one of the two or more lateral surfaces 4 of the two or more battery cells 1. Spring lamellae 22A, 22D are formed, embedded, injected, and / or cast on or in the concave contact surfaces 21A, 21D.

[0085] Thus, the electrical parallel connector 20A has two concave contact surfaces 21A on opposite sides of the electrical parallel connector 20A, against each of which a lateral surface 4 of one of two battery cells 1 rests.

[0086] The electrical parallel connector 20D is designed analogously to the electrical parallel connector 20A, although more than two battery cells 1 can be connected here. The electrical parallel connector 20D is designed as a strut, which can be arranged, for example, between two cell rows. Such a strut can, for example, run transversely to a longitudinal direction of the holders 5.

[0087] The respective insertion direction for the electrical parallel connectors 20A, 20D is also indicated by an arrow in Fig.2, wherein both electrical parallel connectors 20A, 20D can be designed such that they can be inserted (only) from above or in the longitudinal direction of the battery cells 1 between two battery cells 1 (or between two cell rows).

[0088] By means of the electrical parallel connectors 20A, 20B, 20C, 20D, all battery cells 1 of the electrical energy storage device 30 can be electrically connected in parallel with one another, thereby enabling, for example, voltage equalization between the battery cells 1. It is conceivable that only one embodiment or multiple embodiments of the electrical parallel connectors 20A, 20B, 20C, 20D can be installed in the electrical energy storage device 30. List of reference symbols 1 battery cells 2 cell contacts 3 End faces of the housing 4 Housing surfaces 5 battery cell holders 10 electrical series connectors 20A-20D electrical parallel connectors 21A-21D Contact surfaces of the parallel connectors 22A, 22D Spring lamellas of the parallel connectors 22B, 22C Legs of the parallel connectors 23B, 23C End structures of the parallel connectors 30 Electrical energy storage 50 motor vehicles 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] WO 2021 / 042141 A1

[0006] CN 211208498 U

[0007] WO 2016 / 053425 A1

[0008] DE 10 2019 208 949 A1

[0009] EP 4 080 672 A1

[0010]

Claims

[1] Electrical energy storage device (30) for a motor vehicle (50), the electrical energy storage device (30) comprising: - battery cells (1), each comprising a housing (3, 4) and a cell contact (2) formed in or on the housing (3, 4), wherein the cell contact (2) forms a first electrical pole and the housing (3, 4) forms a second electrical pole; and - a cell contact system for establishing an electrical connection between the battery cells (1), characterized by , that - the cell contacting system has electrical parallel connectors (20A; 20B; 20C; 20D) which each electrically connect two lateral surfaces (4) of the housings (3, 4) of two of the battery cells (1). [2] Electrical energy storage device (30) according to claim 1, characterized by that the electrical parallel connectors (20A; 20B; 20C; 20D) each - are designed as a clamp and / or spring element, and / or - are mechanically prestressed between the two battery cells (1) and / or are clamped between the two lateral surfaces (4). [3] Electrical energy storage device (30) according to claim 1 or 2, characterized by that the electrical parallel connectors (20B; 20C) each have two legs (22B; 22C), on each of which a contact surface (21B; 21C) is formed for one of the two lateral surfaces (4). [4] Electrical energy storage device (30) according to claim 3, characterized by that the two legs (22B; 22C) - are mirror-symmetrical to a longitudinal axis of the respective electrical parallel connector (20B; 20C) and / or - each have a shape which is curved at least in sections, such that the respective contact surface (21B) is designed to be at least partially adapted to the shape of one of the two lateral surfaces (4). [5] Electrical energy storage device (30) according to claim 3 or 4, characterized bythat the electrical parallel connectors (20B; 20C) each have an end structure (23B; 23C) which connects the two legs (22B; 22C) to each other, wherein the end structure (23B; 23C) - is arrow-shaped and / or barbed, and / or - is designed such that a plug-in direction for plugging in the respective electrical parallel connector (20B; 20C) between the two of the battery cells (1) runs only in a longitudinal direction or in a transverse direction of the two of the battery cells (1). [6] Electrical energy storage device (30) according to claim 1 or 2, characterized by that the electrical parallel connectors (20A; 20D) each have a wave-shaped course, wherein concave contact surfaces (21A; 21D) for the respective contact of one of the two or more lateral surfaces (4) of the two or more battery cells (1) are formed by the wave-shaped course. [7] Electrical energy storage device (30) according to claim 6, characterized by that spring lamellae (22A; 22D) are formed, embedded, injected and / or cast on or in the concave contact surfaces (21A; 21D). [8] Electrical energy storage device (30) according to one of claims 1 to 7, characterized by , that - the electrical parallel connectors (20A; 20B; 20C; 20D) each have several metal layers and / or are designed as bi-metal, and / or - the electrical parallel connectors (20A; 20B; 20C; 20D) consist at least partially of carbon, soot and / or carbon nanotubes and / or comprise metal particles. [9] Electrical energy storage device (30) according to one of claims 1 to 8, characterized byin that the cell contacting system has electrical series connectors (10) which each electrically connect the cell contact (2) of one of the battery cells (1) and an end face (3) of the housing (3, 4) of another of the battery cells (1), said end face (3) surrounding the cell contact (2). [10] Motor vehicle (50), characterized by that the motor vehicle (50) comprises the electrical energy storage device (30) according to one of claims 1 to 9.

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