Device and method for welding cell connectors to electrical poles of individual cells

Abstract

The invention relates to a device with a number of hold-down devices (10) and a laser welding device (7) for welding a plate-shaped cell connector unit (2) having a plurality of cell connectors (4) to electrical poles (P) arranged on a narrow side (S) of a prismatic cell housing (5) of individual cells (1) combined to form a cell assembly (Z) and positioned relative to one another for electrical interconnection to form an electrical energy storage device. According to the invention, the device comprises an integral tool (3) with - a web-shaped base support (8), - a plurality of suction nozzles (9) arranged alternately along a longitudinal axis of the base support (8) for receiving the cell connector unit (2) and a plurality of hold-down devices (10) for applying a hold-down force to the cell connectors (4) of the cell connector unit (2) to be welded to the electrical poles (P) of the adjacent individual cells (1), and - a robot and / or gantry axis connection (11) arranged at one end of the base support (8). Furthermore, the invention relates to a method for welding cell connectors (4) to electrical poles (P) of individual cells (1).

Description

The invention relates to a device having a number of hold-down devices and a laser welding device for welding a plate-shaped cell connector unit having a plurality of cell connectors, having electrical poles, which are arranged on a narrow side of a prismatic cell housing, of individual cells which are combined to form a cell composite and are positioned with respect to one another for the electrical interconnection, for forming an electrical energy store. The invention further relates to a method for welding a plate-shaped cell connector unit having a plurality of cell connectors to electrical poles, arranged on a narrow side of a prismatic cell housing, of individual cells combined to form a cell composite and positioned with respect to one another for the electrical interconnection.DE 10 2020 006 154 A1 discloses a device and a method for joining cell arresters and cell connectors of an electric battery with a cell block comprising a plurality of individual cells and their cell frames by means of laser welding. The device comprises a hold-down device for applying a hold-down force to two cell arresters lying one above the other and a cell connector, and a laser welding device for producing a welded connection between the cell arresters and the cell connector. The holding-down device is flexibly mounted and arranged on the cell block below the two cell arresters on a bearing region of the same contours, wherein the contours are raised with respect to their surroundings. Sections of the contours forming the bearing region extend in the direction of the cell arresters and, when the hold-down force is applied in the region to be welded, the cell holders are bent corresponding to one another and the two cell arresters lie on one another over the full surface in this region.The object of the invention is to specify a novel device and a method for welding a cell connector unit to electrical poles of at least two individual cells of an electrical energy store.The object is achieved according to the invention by a device which has the features specified in claim 1 and by a method which has the features specified in claim 4.Advantageous embodiments of the invention are the subject matter of the dependent claims.A device comprises a number of hold-down devices and a laser welding device for welding a plate-shaped cell connector unit having a plurality of cell connectors to electrical poles, arranged on a narrow side of a prismatic cell housing, of individual cells combined to form a cell composite and positioned with respect to one another for the electrical interconnection, for forming an electrical energy store. According to the invention, the device has an integral tool with a web-shaped base carrier, a plurality of suction connectors arranged reciprocally along a longitudinal axis of the base carrier for receiving the cell connector unit, and a plurality of hold-down devices for applying a hold-down force to the cell connectors of the cell connector unit to be welded to the electrical poles of the individual cells, and a robot and / or portal axle connection arranged at one end of the base carrier.Such a device is suitable for handling and welding the cell connector units to the electrical poles of the individual cells, wherein there is only a single positioning effort of the integral tool with the cell connector unit with respect to the electrical poles.By means of this device, individual process steps can be omitted, so that a smaller space requirement is required in the production of an electrical contact between cell connector unit and electrical poles of the individual cells, and a reduction in cycle time can be realized.Because a plurality of handling operations can be omitted, precision in the electrical contacting can be increased, wherein installation technology and installation costs associated therewith can be reduced.The device, in particular the integral tool, can be integrated comparatively trivially into a series production, in particular by adapting the integral tool to a portal axis system and / or to a robot.The integral tool can be operated together with a conventional plant technology, for example a scanner welding optics, etc., in a production environment.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 cell assembly having a plurality of individual cells, FIG. 2 schematically shows a perspective view of an integral tool positioned with respect to a cell connector unit, and FIG. 3 schematically shows the cell assembly and the integral tool during welding of cell connectors of the cell connector unit to electrical poles of the individual cells.Corresponding parts are provided with the same reference numerals in all figures.FIG. 1 shows a perspective view of a cell composite Z having a plurality of individual cells 1.FIG. 2 shows a perspective view of an integral tool 3 positioned with respect to a cell connector unit 2, and FIG. 3 shows the cell assembly Z and the integral tool 3 when welding cell connectors 4 of the cell connector unit 2 to electrical poles P of the individual cells 1.As FIG. 1 shows, the individual cells 1 have a prismatic, in particular a cuboidal, cell housing 5. In this case, two electric poles P are arranged on a long narrow side S, in particular on a narrow side S directed upward in the direction of a vertical axis.To form an electrical energy store, the individual cells 1 combined to form a cell composite Z and positioned with respect to one another are electrically contacted, wherein the planar and plate-shaped cell connector unit 2 is provided for this purpose. This cell connector unit 2 has cell connectors 4 which are arranged in two rows and are positioned corresponding to the positions of the electrical poles P of the individual cells 1 and are integrated into a carrier element 6, wherein the carrier element 6 and the cell connectors 4 form the cell connector unit 2. In this case, a position of the cell connectors 4 integrated into the carrier element 6 corresponds to positions of electrical poles P of the individual cells 1 of the cell assembly Z in order to electrically interconnect two adjacent individual cells 1 with one another.In one embodiment, the cell connectors 4 are designed as separate components or the cell connectors 4 are integrated into a plate-shaped cell connector unit 2, wherein the cell connectors 4 are positioned at a predetermined distance from one another.Usually, many different individual tools, for example grippers, welding hold-downs, etc., are used in a production environment for various process steps, in particular from component removal, handling up to placing on and welding. This large number of comparatively partially complicated tools causes, on the one hand, great outlay with regard to their construction and production and their use. On the other hand, a comparatively large space requirement in a production environment and a higher cycle time due to a plurality of individual process steps are required. A tool which is designed for mounting a cell connector unit 2 on a cell assembly Z is not present here.The following describes an apparatus comprising a laser welding apparatus 7 for laser beam welding and the integral tool 3, wherein the apparatus is provided for welding the cell connectors 4 of a cell connector unit 2 to electrical poles P of individual cells 1 which are combined to form a cell assembly Z.The integral tool 3 has a base carrier 8, on which a plurality of suction nozzles 9 and a plurality of hold-down devices 10 are arranged alternately in the direction of its longitudinal axis. In particular, a respective suction connection 9 is opposed by a holding-down device 10. A robot and / or portal axle connection 11 is arranged at one end of the base carrier 8.A reduced pressure can be generated by means of the suction connectors 9, so that the cell connector unit 2 can be accommodated by means of the suction connectors 9, when these are arranged on the cell connector unit 2. The hold-downs 10 can be extended and retracted automatically with respect to the base support 8 and each comprise a pre-loadable spring element, not shown, which is pre-loaded upon application of a hold-down force, so that the respective hold-down 10 exerts a contact pressure on a cell connector 4 by means of the pre-load, i.e. an acting spring force.Both a position of the respective suction connection 9 and a position of the respective hold-down device 10 are adapted with respect to the cell connector unit 2. The suction connectors 9 are positioned in such a way that they do indeed receive the cell connector unit 2, but do not contact the cell connectors 4 for this purpose. The suction connectors 9 can thus be positioned in a region outside the cell connectors 4, in particular between them, as shown in FIG. 3.The hold-downs 10 are electrically insulated and for this purpose are formed, for example, from a so-called insulator material. Because the hold-downs 10 are designed to be electrically insulated, the integral tool 3 is electrically insulated from the cell connector unit 2 and the cell module Z, so that a risk of short circuit when the integral tool 3 contacts the cell connectors 4 of the cell connector unit 2 and the individual cells 1 can be largely ruled out.A bearing surface of the hold-down devices 10 is rounded, so that a rotational movement of individual cell connectors 4 is possible.During operation of the integral tool 3, the latter is positioned for receiving the cell connector unit 2 via a component carrier, not shown in detail, wherein a generation of negative pressure is activated with respect to the suction connectors 9. The cell connector unit 2 is suctioned by means of the generated negative pressure of the suction connectors 9, removed from the component carrier and positioned on an upper side of the cell assembly Z, i.e. on the narrow sides S, on which the electrical poles P of the individual cells 1 are arranged.In particular, the cell connector unit 2 is positioned on the cell assembly Z by means of the integral tool 3 in such a way that an electrical interconnection of adjacent individual cells 1 is possible by means of the cell connectors 4 integrated into the cell connector unit 2 via contacting of the corresponding electrical poles P. A position of the respective cell connector 4 thus corresponds to positions of electrical poles P of adjacent individual cells 1 to be connected. Dimensions of the integral tool 3, in particular a length dimension of the base carrier 8, are or is selected depending on dimensions of the cell assembly Z, in particular with respect to its longitudinal axis.If the cell connector unit 2 is arranged on the cell assembly Z, the hold-downs 10 are extended and the generation of the negative pressure of the suction connectors 9 is deactivated, wherein the suction connectors 9 remain in a fixed position relative to the cell connector unit 2.The hold-downs 10 are extended, wherein each hold-down 10 applies a hold-down force, in particular with a predefined force level, to a specific central point of application of the cell connectors 4 and the cell connector 4 is thus pressed onto the electrical poles P of adjacent individual cells 1 to be connected by means of the prestressed spring elements, that is to say a specific acting spring force.The central point of application of the hold-downs 10 with respect to the cell connectors 4 is selected such that, in a lateral arrangement with respect to the hold-downs 10, by means of the laser welding device 7, at least one weld seam for connecting the cell connectors 4 to the electrical poles P of the individual cells 1 is introduced into the cell connectors 4 and the electrical poles P in order to connect the cell connectors 4 to the electrical poles P of the adjacent individual cells 1 in a materially integral manner. A welding optics, in particular a so-called scanner welding optics, is separated from the integral tool 3, for example by means of axes and / or robots, moved over the integral tool 3, i.e. positioned relative thereto, and a laser beam is moved to predetermined welding positions.If all individual cells 1 of the cell assembly Z are electrically connected by means of the cell connectors 4 of the cell connector unit 2, wherein the cell connectors 4 are connected in a materially integral manner to electrical poles P of adjacent individual cells 1, the hold-down devices 10 are raised and retracted. The integral tool 3 is then moved into its rest position.The integral tool 3 can be moved and moved via the robot and / or portal axis connection 11.References 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 2020 006 154 A1

[0002]

Claims

Device having a number of hold-down devices (10) and a laser welding device (7) for welding a plate-shaped cell connector unit (2) having a plurality of cell connectors (4) with electrical poles (P) arranged on a narrow side (S) of a prismatic cell housing (5) of individual cells (1) combined to form a cell composite (Z) and positioned with respect to one another for electrical interconnection, for forming an electrical energy store, characterized byan integral tool (3) having - a web-shaped base carrier (8), a plurality of suction nozzles (9) arranged reciprocally along a longitudinal axis of the base carrier (8) for receiving the cell connector unit (2) and a plurality of hold-down devices (10) for applying a hold-down force to the cell connectors (4) of the cell connector unit (2) to be welded to the electrical poles (P) of the adjacent individual cells (1), and a robot and / or portal axle connection (11) arranged at one end of the base carrier (8).Device according to claim 1, characterised in that the respective holding-down device (10) has a spring element which can be prestressed for applying the holding-down force to a cell connector (4) which is to be welded to electrical poles (P).Device according to claim 1 or 2, characterised in that at least the holding-down devices (10) of the integral tool (3) are designed to be electrically insulated.Method for welding a plate-shaped cell connector unit (2) having a plurality of cell connectors (4) with electrical poles (P) arranged on a narrow side (S) of a prismatic cell housing (5) of individual cells (1) combined to form a cell composite (Z) and positioned with respect to one another for electrical interconnection, for forming an electrical energy store by means of a device having a number of hold-downs (10) and a laser welding device (7), characterized in that the device has an integral tool (3) which comprises suction connections (9) arranged alternately along a longitudinal axis of a base carrier (8) and a plurality of hold-downs (10), wherein - the integral tool (3) is moved over a component carrier and the cell connector unit (2) is picked up by means of a generated negative pressure of the suction connectors (9) and positioned thereon with respect to the cell assembly (Z), - the hold-downs (10) are extended and the generation of the negative pressure of the suction connectors (9) is deactivated after the cell connector unit (2) is positioned on the cell assembly (Z), - a holding-down force is applied to a cell connector (4) of the cell connector unit (2) by means of a holding-down device (10) in each case by prestressing a respective spring element, and at least one welded seam for connecting the cell connectors (4) to the electrical poles (P) of the individual cells (1) is introduced into the cell connectors (4) and the electrical poles (P) by means of the laser welding device (7) in a lateral arrangement with respect to the holding-down devices (10), - after the welding of the cell connectors (4) to the electrical poles (P) of the adjacent individual cells (1), the holding-down devices (10) are retracted and the integral tool (3) is moved into a rest position.

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