Cell module for an electrical energy storage device and method for producing a cell module

Abstract

The invention relates to a cell module (Z) for an electrical energy storage device comprising a plurality of individual cells (1), wherein adjacent individual cells (1) are electrically connected by means of a cell connector (3). According to the invention, - an inherently rigid base plate (2) is provided, which has recesses (A) corresponding to electrical poles (P) of the mutually positioned individual cells (1), - the base plate (2) is made of an electrically insulating material and - the cell connectors (3) are or can be integrated into the base plate (2) in at least some sections in areas of the recesses (A) in a form-fitting and / or force-fitting and / or material-fitting manner. Furthermore, the invention relates to a method for producing a cell module (Z).

Description

The invention relates to a cell module for an electrical energy store having a plurality of individual cells, adjacent individual cells being electrically connected by means of a cell connector. The invention further relates to a method for producing a cell module.DE 10 2021 122 034 A1 discloses a method and a device for electrically contacting a battery cell with a metallic connecting element, a cell module and a battery. The battery cell has a housing with a metallic housing cup having a longitudinal axis. In this case, the housing cup has a groove running around the longitudinal axis on an outer jacket. The method comprises providing the connecting element with a first opening, which is adapted to a cross section and / or diameter of the housing cup; bringing the groove and the first opening together and fixing the housing cup in a force-fit and form-fit manner in the first opening of the connecting element.Furthermore, DE 10 2017 213 470 A1 describes a battery module and a battery module stack for a motor vehicle. The battery module comprises:two contacting plates arranged parallel or approximately parallel to one another, comprising a first and a second contacting plate, anda plurality of battery cells which are arranged next to one another and between the two contact plates, whereina battery cell has a longitudinal axis and two axially opposite ends,the ends of a respective battery cell are connected to the contact plates, andthe battery cells are arranged such that an outer circumferential surface of a respective battery cell completely surrounded by adjacent battery cells touches outer circumferential surfaces of three adjacent battery cells, and an outer circumferential surface of a respective battery cell incompletely surrounded by adjacent battery cells touches outer circumferential surfaces of two adjacent battery cells.The invention is based on the object of specifying a novel cell module, which has a plurality of individual cells, for an electrical energy store and a method for producing such a cell module.The object is achieved according to the invention by a cell module which has the features specified in claim 1 and by a method which has the features specified in claim 8.Advantageous embodiments of the invention are the subject matter of the dependent claims.A cell module for an electrical energy store has a plurality of individual cells, adjacent individual cells being electrically connected by means of a cell connector. According to the invention, a self-rigid base plate is provided, which has recesses corresponding to electrical poles of the individual cells positioned with respect to one another. In this case, the base plate is formed from an electrically insulating material and the cell connectors can be integrated or integrated at least in sections in regions of the recesses in a form-fit and / or force-fit and / or firmly bonded manner into the base plate.By means of such a base plate, the individual cells can be pre-fixed comparatively well and exactly prior to adhesive bonding in and / or prior to introducing potting compound into a housing of the electrical energy store, so that tilting of the individual cells in particular during adhesive bonding and / or introduction of the potting compound can be ruled out to the greatest possible extent.By means of the individual cells pre-fixed on the base plate, both handling and further processing of the cell module can be improved, wherein complicated devices and a clamping technique can be omitted. For example, such a cell module comprising the base plate, which is damaged, can be removed comparatively easily from the housing of the electrical energy store in order to replace or repair the cell module. Thus, maintenance cost and maintenance cost can also be reduced.In addition, such a cell module represents an optimized component assembly by functional integration into the base plate.By means of the base plate, in particular the recesses, welding regions for the materially bonded connection of the cell connectors to the electrical poles of individual cells to be electrically connected are enlarged and are accessible in an improved manner.In one embodiment, the base plate is formed from a plastic or from a fiber-reinforced plastic, so that a stiffness of the base plate can be ensured to the greatest possible extent or even increased. The base plate can also be used to increase a rigidity of the housing of the electrical energy store. In addition, the base plate can serve to introduce a force specifically into a predefined region of the individual cells in the event of damage, in particular deformation, of the housing. Damage to the individual cells, in particular their opening and the escape of substances harmful to health, can thus be substantially avoided.In one embodiment, the cell connectors formed from a metal can be integrated into the base plate by means of a clip connection, so that it is possible, for example, to remove a damaged cell connector, in particular with respect to the base plate, from the base plate in a non-destructive manner.In a further embodiment, the cell connectors are introduced into the base plate in a materially integral manner by means of a casting and / or printing process. The cell connectors are thus integrated into the base plate in a materially integral manner, so that they are held and fixed relatively securely.In one embodiment, a contact element for tapping cell voltage is introduced into the base plate. Since, in addition to the cell connectors, the at least one contact element is integrated into the base plate, the cell module with the base plate, the integrated cell connectors and the integrated contact element represents an optimized compact component assembly.In a further embodiment, the respective cell connector is connected to a respective electrical pole of adjacent individual cells in a materially integral manner, wherein this connection is in particular a permanent connection and the electrical connection of the individual cells is optimized by means of such a materially integral connection, since the cell connector and the corresponding electrical pole are partially fused, so that the materials, in particular the metals, connect to one another in a materially integral manner and the electrical connection is thereby produced.In one embodiment, the individual cells are round cells and each have a circular cylindrical cell housing which is closed by means of a cell cover on which the electrical poles of the individual cell are arranged and / or formed. In this case, use of such a base plate is not restricted to a cell module with round cells. Such a base plate can also be placed on individual cells with a prismatic housing, in particular a rectangular housing, in particular if the electrical poles are arranged on one side, in particular a narrow side, of a cell housing. The recesses of the base plate are then designed to correspond to a shape and configuration of the electrical poles of such a cell housing shape.The invention furthermore relates to a method for producing a cell module of an electrical energy store having a plurality of individual cells, adjacent individual cells being electrically connected by means of a cell connector. According to the invention, it is provided thata self-rigid base plate with recesses corresponding to electrical poles of the individual cells positioned relative to one another is placed on the individual cells,electrical poles of adjacent individual cells are electrically interconnected by means of cell connectors integrated into the base plate,the base plate placed on the individual cells is braced in the direction of the individual cells and / or the individual cells are braced in the direction of the base plate placed on it, andthe cell connectors are connected in a materially integral manner to the electrical poles of adjacent individual cells to be electrically connected.By means of the method and the use of such a base plate, it is possible to represent the cell module as an optimized compact component assembly. A production process chain of the cell module can be made flexible by means of the method, since the cell module can also be glued to the electrical poles of the individual cells, for example, after welding the cell connectors, and the handling of the cell module is simplified by means of the base plate, in particular since the individual cells are pre-fixed. In addition, a quality of such a cell module can be improved, since no load acts on a connecting region, in particular in the form of a weld seam.In one possible embodiment of the method, the cell connectors are connected by means of laser beam welding to the electrical poles of the individual cells to be electrically connected in a materially integral manner. The compact component assembly is thus formed, which optimizes the handling and processing of the cell module. For example, the cell connectors and the electrical poles are connected by remote laser beam welding, in that a welding robot with a scanner welding optics travels over the cell module and connects the cell connectors by laser beams to the electrical poles in a materially integral manner to individual cells to be electrically connected.Exemplary embodiments of the invention are explained in more detail below with reference to drawings.The following are shown: FIG. 1 schematically shows a perspective view of a plurality of individual cells, a base plate and a plurality of cell connectors for forming a cell module, FIG. 2 schematically shows a perspective view of the cell module and a sectional view of an enlarged cutout in the connection region between an electrical pole and a cell connector, and FIG. 3 schematically shows a perspective view of the cell module rotated by 180° and a sectional representation of an enlarged section of the connection region corresponding to the 180° rotation.Corresponding parts are provided with the same reference numerals in all figures.FIG. 1 shows a perspective view of an exploded illustration of a cell module Z having a plurality of individual cells 1 designed as round cells, a base plate 2 and a plurality of cell connectors 3.FIG. 2 shows a perspective view of the cell module Z and a sectional illustration of an enlarged section of a connection region between an electrical pole P of an individual cell 1 and a cell connector 3, and FIG. 3 shows a perspective view of the cell module Z rotated by 180° and a sectional illustration of an enlarged section of the connection region corresponding to the 180° rotation.In general, a structure of a cell module Z is comparatively complex and associated with a relatively large number of challenges. For the electrical contacting of the individual cells 1, these are connected by placing and welding a cell connector 3. In this case, in particular an electrical pole P of an individual cell 1 is electrically connected to an electrical pole P of an adjacent individual cell 1. For this purpose, the cell connector 3 is formed from an electrically conductive material, in particular from a metal, wherein a cohesive connection between electrical poles P and cell connector 3 is effected in particular by means of laser beam welding.According to the prior art, the individual individual cells 1 are positioned relatively complexly by means of complex devices in their position with respect to one another and with respect to the cell connector 3. For example, after welding to the cell connector 3, depending on the production process chain, the individual cells 1 are still comparatively movable during subsequent handling and processing, so that forces and / or loads act on connecting regions between electrical pole P, i.e. individual cell 1, and cell connector 3, i.e. on welded contacts, so that damage can occur in the connecting regions.In order to construct the cell module Z as a compact component assembly, the cell module Z is designed as described below.The cell module Z is part of an electrical energy store which has a number of such cell modules Z which are electrically interconnected with one another. In particular, the electrical energy store is a vehicle battery, in particular a traction battery, for an electric vehicle, a hybrid vehicle or a vehicle operated with fuel cells.As described above, the individual cells 1 are designed as round cells and each have a circular cylindrical cell housing 4 which is closed by means of a cell cover 5. On the cell cover 5, the electrical poles P of the individual cell 1 are arranged and / or formed in an electrically insulated manner from one another. In this case, one electrical pole P is designed as a negative pole and another electrical pole P is designed as a positive pole of the individual cell 1.In order to be able to avoid as far as possible that forces and / or loads act on the connection region between cell connector 3 and electrical pole P of the respective individual cell 1, which forces and / or loads can lead to damage and, under certain circumstances, as a result an electrical connection between individual cells 1 is interrupted and as a result possibly imminent failure of the cell module Z, the use of such a base plate 2 is provided.The base plate 2 is inherently rigid and is formed from an electrically insulating material, for example from a thermoplastic. For example, the base plate 2 can be formed from a fiber-reinforced plastic, in particular thermoplastic, in order to increase a rigidity of the base plate 2.In predetermined regions, in particular depending on a respective position of the individual cells 1, in particular adjacent individual cells 1, wherein the individual cells 1 have their position provided for forming the cell module Z, the base plate 2 has recesses A of different shape. The shapes of the recesses A of the base plate 2 correspond to the shapes of the electric poles P of the individual cells 1.In addition, an underside of the base plate 2, that is to say a flat side of the base plate 2 facing the individual cells 1, is designed in such a way that receptacles, not shown in more detail, in particular in the form of circular material recesses, are provided. A respective receptacle is assigned to an individual cell 1.The cell connectors 3 are formed from a metallic material, for example copper and / or aluminum, and in a possible embodiment are integrated into the base plate 2 or can be integrated into the latter. For example, the respective cell connector 3 can be integrated into the base plate 2 in a form-fit and / or force-fit manner by means of a clip connection. Alternatively or additionally, the cell connectors 3 can be embedded in the base plate 2 by means of a printing and / or casting process, i.e. integrated in the base plate 2 in a materially bonded and positive-locking manner.An electrical contact element, not shown in more detail, for a cell voltage tap, as described above, can also be integrated into the base plate 2.To produce the cell module Z, the base plate 2 is placed on the individual cells 1, so that one of the two electrical poles P is arranged, corresponding to its shape, in a recess A corresponding to the shape, i.e. projects into the latter, as is shown in FIGS. 2 and 3. The other electrical pole P, which is formed directly by means of the cell cover 5, can be contacted by means of the cell connector 3 through the respectively remaining cutout A.If the base plate 2 is placed on the individual cells 1 in a positioned manner corresponding to the individual cells 1 and their electrical poles P, the base plate 2 is braced in the direction of the individual cells 1 and / or the individual cells 1 are braced in the direction of the base plate 2. The base plate 2 can thus replace hold-downs with pressure elements acting on the cell connectors 3. As a result, accessibility to a potential welding region can be improved, wherein the welding region is enlarged, so that a so-called welding-on-the-fly is possible, which can result in shorter cycle times during the production of the cell module Z.In the production process, the base plate 2 serves as a fixing and positioning unit for the individual cells 1 relative to the base plate 2 and thus to the cell connectors 3, wherein the base plate 2, for example as a stiffening element, is installed together with, in particular in, the vehicle after completion of the cell module Z.The base plate 2 enables handling and machining of the comparatively less stiff and non-bonded cell module Z after an introduction of a weld seam S for connecting the cell connectors 3 to the electrical poles P of adjacent individual cells 1, without a load substantially acting on the introduced weld seam S.Furthermore, the base plate 2 can have integrated indexing units or fixing elements in order to optimize fixing of the individual cells 1 on or in the base plate 2. For example, the individual cell 1 can then likewise be held in a predefined position by means of a clip connection and / or a screw connection.In a further embodiment, it is provided that base plates 2 of a plurality of such cell modules Z are connected to one another to form an overall cell module, for example by means of a number of screw connections. As a result, an inherent rigidity of this overall cell module thus formed can be increased.List of reference characters1 Single cell 2 Base plate 3 Cell connector 4 Cell housing 5 Cell cover A Cutout P Electrical pole S Welded seam Z Cell moduleReferences included in the specificationThis list of documents cited by the applicant has been produced in an automated manner and is only included for the better information of the reader. The list is not part of the German patent application or utility model application. The DPMA does not take any adhesion for any faults or omissions.Patent Literature citedDE 10 2021 122 034 A1

[0002] DE 10 2017 213 470 A1

[0003]

Claims

Cell module (Z) for an electrical energy store having a plurality of individual cells (1), wherein adjacent individual cells (1) are electrically connected by means of a cell connector (3), characterized in that - a self-rigid base plate (2) is provided, which has recesses (A) corresponding to electrical poles (P) of the individual cells (1) positioned with respect to one another, - the base plate (2) is formed from an electrically insulating material and - the cell connectors (3) can be integrated or integrated at least in sections in the regions of the recesses (A) in a form-fitting and / or force-fitting and / or firmly bonded manner into the base plate (2).Cell module (Z) according to Claim 1, characterized in that the base plate (2) is formed from a plastic or from a fibre-reinforced plastic.Cell module (Z) according to Claim 1 or 2, characterized in that the cell connectors (3) formed from a metal can be integrated into the base plate (2) by means of a clip connection.Cell module (Z) according to one of the preceding claims, characterized in that the cell connectors (3) are introduced into the base plate (2) in a materially integral manner by means of a casting and / or printing process.Cell module (Z) according to one of the preceding claims, characterized in that at least one contact element for tapping cell voltage is introduced into the base plate (2).Cell module (Z) according to one of the preceding claims, characterized in that the respective cell connector (3) is connected in a materially integral manner to in each case one electrical pole (P) of adjacent individual cells (1).Cell module (Z) according to one of the preceding claims, characterized in that the individual cells (1) are round cells and each have a circular cylindrical cell housing (4) which is closed by means of a cell cover (5) on which the electrical poles (P) of the individual cell (1) are arranged and / or formed.Method for producing a cell module (Z) of an electrical energy store having a plurality of individual cells (1), wherein adjacent individual cells (1) are electrically connected by means of a cell connector (3), characterized in that - a self-rigid base plate (2) having cutouts (A) corresponding to electrical poles (P) of the individual cells (1) positioned with respect to one another is placed on the individual cells (1), - electrical poles (P) of adjacent individual cells (1) are electrically connected by means of cell connectors (3) integrated into the base plate (2), - the base plate (2) placed on the individual cells (1) is braced in the direction of the individual cells (1) and / or the individual cells (1) are braced in the direction of the placed base plate (2), and - the cell connectors (3) are materially bonded to the electrical poles (P) of adjacent, mutually rigid cells, The individual cells (1) to be electrically connected can be electrically connected.Method according to Claim 8, characterized in that the cell connectors (3) are connected by means of laser beam welding to the electrical poles (P) of the individual cells (1) to be electrically connected by means of a material bond.

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