DE102021119695A1 - Electrical connection device - Google Patents

Abstract

The present invention relates to an electrical connection device, as is provided in energy storage devices as a connection between connections of individual cells or also of modules formed from cells for their interconnection. In order to create an electrical connection device suitable for dismantling and/or reassembly as connections between the connections of individual cells of an energy store and a corresponding energy store, it is proposed that a separate component (1) be connected to the respective cell pole (5), preferably by a Welding (7), the separate component (1) as an adapter being a detachable part of the cell connector (9).

Description

The present invention relates to an electrical connection device, as is provided in energy storage devices as a connection between connections of individual cells or also of modules formed from cells for their interconnection.

• - Schweißen
• - Bonden
• - Schrauben
• - Stecken
• - Falten, Falzen, Bördeln oder Zusammenbiegen.

Electrical connecting devices of the above type are in energy stores, such as are provided in the form of rechargeable high-voltage batteries in modern electric vehicles, necessary to here a variety of standard charge carriers, such as individual batteries or battery cells, in all To connect operating states electrically conductive with each other and to interconnect. This is the only way to maintain a specified voltage level and a minimum current to be supplied. A failure of just one electrical connection device can lead to a failure of an entire energy store. Therefore, the following joining processes are currently mainly used to produce permanently reliable and electrically highly resilient connecting devices:

• - welding
• - bonding
• - screws
• - Put
• - Folding, folding, flanging or bending together.

What all of the methods mentioned above have in common is that they create a solid material, form-fitting or non-positive connection between the connections of individual cells. Replacing the currently still quite expensive cells or other components is usually hardly possible given the state of the art. If a component is defective, the entire affected module must be sorted out. It also means that no components can be reused. Any type of recycling leads to such an increased effort due to any residual charge in the individual cells that at the moment it is more common to shred, melt down or even thermally recycle defective or used energy storage devices than to replace or repair them. Current recycling guidelines for used batteries are to be considered obsolete. Therefore, in the near future there will be specific collection and/or recycling targets for e-vehicle batteries in order to use defective energy storage as a source of raw materials.

A number of approaches are known from the prior art for achieving not only reliable contact but also replacement of individual cells by screwing the cells together for electrical contact and targeted interconnection. So reveals the DE 10 2018 204 346 B3 an arrangement for the electrical connection of pole terminals, the connection being made by a screw connection. Reference contours are attached to the connector, which can be transferred from a module connection to a cell connection for positioning in an automated screw connection and shows the possibility of an automated screw connection of connectors.

EP 2 506 358 B1 describes a detachable coupling part that can be fixed without a welding process. The coupling part is designed as a threaded bolt, which is led out of the cell pole. Nuts are screwed onto these threaded bolts, with which the cell connectors are connected to cells of a prismatic design.

DE 10 2012 222 712 A1 describes cell poles for electrically contacting electrodes of a storage cell, the cell pole having a T-groove or a dovetail groove.

The cell connectors are welded to all cell poles except for those of the outer cells in the module. The outer cell poles in the module are required for the module connection, for which purpose sliding blocks with threaded bolts are inserted into the slot. These can be screwed to a connector with a nut. This is a detachable connection between modules. The other cells in the module could be screwed on in the same way if a welding process is replaced by the screwing process described.

U.S. 5,942,353A discloses a battery module with replaceable cells. For this purpose, each cell of a module has two threaded bolts, each of which represents the plus and minus pole. The studs protrude from the cell housings and an electrically conductive connector is secured to each with nuts. A cap is attached to the connector for electrical insulation.

DE 20 2006 018 313 U1 describes a pole insert for attaching a pole screw to a pole. The insert has an unthreaded bore into which a self-tapping pole screw is screwed.

A technical disadvantage of the prior art is that a respective cell pole has to be modified geometrically for the connection of known detachable cell connections. However, according to the manufacturer, this is generally not permitted.

It is therefore the object of the present invention to create an electrical connection device suitable for disassembly and/or reassembly as a connection between terminals of individual cells of an energy storage device and a corresponding energy storage device, through which the aforementioned disadvantages are significantly alleviated.

This object is achieved according to the invention by the features of claim 1 in that a separate component is connected to the respective cell pole, preferably by welding, the component itself being a detachable part of the electrical connection device or cell connector. For reasons of rationality, welding is preferably still used as a quick, reliable and inexpensive solution for an electrical and mechanical connection of the cell connector on or at a terminal of the cell for fixing the additional component to the relevant pole contact. According to the invention, the electrical connection device is designed as a separate component which is connected on the one hand to the respective cell pole, e.g. by welding, and on the other hand is detachably connected to the cell connector as an adapter. This creates a connection between a cell and a cell connector that can fundamentally be removed and reinstalled.

A contradiction existing according to the state of the art is resolved by a solution according to the invention: For the connection of known detachable cell connections, a respective cell pole has to be changed geometrically. On the other hand, according to the manufacturer, this is usually not permitted or not permitted to the extent required. An electrical connection and fixation of an additional component, on the other hand, has been sufficiently tested and permitted, whereby the geometry of a cell pole is not changed by welding, and the specifications of the cell manufacturer are not violated. The above contradiction is thus resolved by the introduction of a separate component which is connected to the respective cell pole by welding, the separate component in turn being a detachable part of the electrical connection device. As such, the separate component can be detached from the electrical connection device and connected to it again.

Advantageous developments of the invention are the subject matter of the dependent claims. Accordingly, the component is designed or prepared as an element of a screw connection with or on the electrical connection device. According to one embodiment of the invention, the component carries a threaded bolt. In an alternative embodiment of the invention, the component has a recess for receiving or passing through a screw or screw connection.

According to a preferred embodiment of the invention, the component is part of a preassembled assembly that has at least one screw connection. The cell connector is therefore pre-assembled with at least one screw connection, with the cell connector being welded as a pre-assembled assembly or unit to two cell poles.

According to an advantageous further development, the connector has a slot in the area of the screw connection or a recess that runs freely towards an edge of the connector. Both are measures to compensate for tolerances, which serve to reduce static mechanical stresses.

In one embodiment of the invention, the component is designed as a welded stud with a thread. Alternatively, the additional component is designed as a welding lip, which is designed as a plug connector and is preferably additionally secured in an insert by a screw connection.

In an essential development of the invention, a welding surface in a U-shape or in the form of a rectangular frame is provided on the component. In this embodiment of the invention, it has turned out to be advantageous to change the shape of the welding surface by adapting the weld seam geometry in this way in order to achieve an increase in the strength of the weld seam as a goal.

The additional component advantageously has a bend between the welding surface and the area designed for a screw connection. This bending of the additional component causes a change in the force flow in its direction of action and/or plane of action when loosening and/or making the screw connection. This also reduces mechanical stress on the welding of the component in the area of the welding surface and/or the cell pole. At the same time, accessibility of an area around the screw connection for tools is improved.

In a further development of the invention, a torque support is provided on the additional component with adaptation to an external tool. For this purpose, for example, a contact or engagement surface is formed on the additional component in the form of a "U" or a hexagon. For the same technical purpose, a contour is formed on the additional component to be used together with a cover of the cell, a spacer between the cells and/or Pole inserts or other framework of the electrical storage cell to form a torque support.

• 1: eine perspektivische Ansicht eines ersten Ausführungsbeispiels eines separaten Bauteils;
• 2a: die Ansicht von 1 nach einem Verschweißen des separaten Bauteils mit einem Zell-Pol einer elementaren Speicherzelle;
• 2b: die Ansicht von 2a nach Montage eines Zellverbinders zum Verbinden von Zell-Polen zweier benachbart angeordneter Speicherzellen;
• 3a bis 3d: Draufsichten von Ausführungsbeispielen mit Varianten einer Momentenstütze;
• 4a bis 4d: Schnittdarstellungen jeweils zu den 3a - 3d;
• 5: eine Draufsicht auf eine Anordnung analog 2b mit Darstellung eines abgewandelten Fertigungsverfahrens;
• 6a: eine Ansicht gemäß 2b zur Darstellung besondere Schritte eines Fertigungsverfahrens;
• 6b: die Ansicht von 3a mit einem alternativen Fertigungsverfahren;
• 7: eine perspektivische Ansicht eines weiteren Ausführungsbeispiels separater Bauteile als vorgefertigte und vormontierte Baugruppe analog 3b;
• 8a und 8b: Draufsichten auf je ein separates Bauteil mit unterschiedlichen Geometrien der Verschweißung und
• 9: eine perspektivische Ansicht eines kompletten Moduls für eine Hochvolt-Speicherzelle.

Further features and advantages of embodiments according to the invention are explained in more detail below with reference to exemplary embodiments using the drawing. It shows in a schematic representation:

• 1 1: a perspective view of a first exemplary embodiment of a separate component;
• 2a : the view of 1 after welding the separate component to a cell pole of an elementary storage cell;
• 2 B : the view of 2a after mounting a cell connector for connecting cell poles of two adjacently arranged storage cells;
• 3a until 3d : top views of exemplary embodiments with variants of a moment support;
• 4a until 4d : Sectional views of each 3a - 3d ;
• 5 : a plan view of an arrangement analogous 2 B with representation of a modified manufacturing process;
• 6a : a view according to 2 B to show special steps of a manufacturing process;
• 6b : the view of 3a with an alternative manufacturing process;
• 7 : a perspective view of a further exemplary embodiment of separate components as a prefabricated and preassembled assembly group 3b ;
• 8a and 8b : Top views of a separate component with different geometries of the weld and
• 9 : a perspective view of a complete module for a high-voltage storage cell.

The same reference symbols are always used consistently throughout the various figures of the drawing for the same elements or method steps. Without limiting the invention, only one use of an electrical connection device according to the invention in connection with prismatic cells for use in a motor vehicle on land, on water and/or in the air is illustrated and described below. However, it is obvious to the person skilled in the art that an adaptation to other cell designs is possible in the same way, as well as stationary applications in buffer storage tanks, e.g. in solar or wind energy systems.

1 shows a perspective view of a first embodiment of a separate component 1. Here, a piece of sheet metal, which as a stamped and bent part with a slightly curved structure has two end bearing surfaces 2, 3, creates a solution to the problem, according to which a respective The cell pole must not be changed geometrically for the electrical and mechanical connection of detachable cell connectors, otherwise a manufacturer's guarantee would expire. In this exemplary embodiment, a fastening means 4 in the form of a screw bolt is provided on the separate component 1 between the bearing surfaces 2, 3 for the formation of a detachable cell connection, which is illustrated and described below in the drawing. This component 1 creates a local separation of the connection to a geometrically unchangeable cell pole and the attachment of a detachable electrical and mechanical connection to a cell connector in the manner of an adapter.

2a shows the view from 1 after the separate component 1 has been welded to one of the two bearing surfaces 2, 3 with a cell pole 5 of an elementary storage cell 6. In this exemplary embodiment, the bearing surface 2 is designed to be larger than the bearing surface 3. An approximately rectangular weld 7 is arranged here, through which the separate component 1 introduced according to the invention is now electrically and mechanically permanently connected to the cell pole 5 of the elementary storage cell 6 . A stress on the weld 7 by a normal force F _n and a torque via the screw connection on the screw bolt 4 is reduced in this exemplary embodiment, as will be described below. The cell pole 5 has thus not been changed geometrically. From a mechanical point of view, a force application point of a connection that can be released mechanically via the screw bolt 4 and a mechanical connection between the cell pole 5 of the elementary storage cell 6 have been decoupled or separated from one another and separated locally or spatially. This and the advantages that can be achieved in this way are discussed below, also with reference to a further exemplary embodiment, in particular with reference to the illustration in FIG 6 yet to be addressed.

2 B shows the view from 2a after assembly of a cell connector 9 for connecting cell poles 5 of two adjacent storage cells 6 via the screw bolts 4 of the respective separate adapter components 1 after they have been welded to the cell poles 5. A cell connector 9 is thus attached to cell poles 5 by tightening an arrangement detachably fixed from one nut each with washers 10.

Conventional weld seams between the cell pole 5 and the separate component 1 as an adapter element serve to transmit current and at the same time to absorb operating forces. The welds in an arrangement as follows 2 B experience at least one moment load in the course of the cell connector assembly and disassembly, but must not be subjected to greater loads due to the lack of strength of the electrically highly conductive and therefore mechanically rather soft materials used. The solution here is a breakdown of the functions, ie an electrical connection is made via the weld with the introduction of a relief structure to absorb mechanical forces, especially a moment load. Mechanical stress on the weld 7 via the screw connection on the screw bolt 4 is reduced in this exemplary embodiment by changing local properties to increase static friction F _r between the cell pole 6 and the separate component serving as an adapter, here for example by local use a friction foil 8 in interaction with the second bearing surface 3, see 2a . A mechanical load on the weld 7 due to a screw connection or its loosening is reduced in this way. A kind of moment support is formed.

This approach to the formation of a torque arm is described below using further exemplary embodiments with reference to the figure sequences in FIG 3a-3d and 4a-4d picked up. Further examples are presented here of creating an electrical connection via a weld seam while introducing a relief structure for absorbing mechanical forces. The figure from shows 3a a top view of a section of a module 11 with cell poles 5 of four elementary storage cells 6 and their electrical interconnection by the two cell connectors 9 indicated by dashed lines according to the illustration in FIG 2 B , but without the releasable fixation by a nut with washers 10 per bolt 4. A view of a sectional plane AA of 3a is in 4a shown. Out of 4a it can be seen that in this implementation of the embodiment of FIG 2 B the separate component 1 fixed on each cell pole 5 protrudes beyond a module housing 12. This area is in 4a bordered only on one flank of the separate component 1 with a dotted line as an example. In contrast, in the embodiment of 3b and 4b the module housing 12 or a cover as part of the module housing 12 closed around the cell poles 5 is designed in such a way that shoulders 13 extend up to the level of the separate components 1 . In enclosing contact with each of the separate components 1 fixed on the cell poles 5, these shoulders 13 serve as a so-called moment support by building up a supporting counterforce when the separate components 1 are loaded in the course of tightening or loosening a screw connection on one of the screw bolts 4 .

In the embodiment according to the 3c and 4c A shoulder 13 formed on a so-called spacer 14 as a modified separator between adjacent cells 6 serves in an analogous manner as a moment support. Finally, in the embodiment according to the 3d and 4d so-called. Pole insert parts 15 are used to construct a moment support around each of the separate components 1 of the individual cells 6 in an analogous manner.

5 represents a plan view of an arrangement analogous 2 B Dar showing a step of a modified manufacturing process. A change in the local property by separating the power flow is achieved by using an external mechanically grounded tool 16 which derives the power from the separate component 1 and the cell pole 5 . The tool 16 shown here, which partially encloses the separate component 1, also causes a moment of rest in the form of a spanner drawn in dashed lines as a standard tool when tightening or loosening the nut on the washers 10 on the threaded bolt 4. This means that there is no significant load on the weld 7 and the relevant cell pole 5.

To compensate for relative movements between the cell poles 5, known cell connectors have a balancing shaft 17, which 5 is designed as part of the connector 9. However, this balancing shaft 17 increases the current-carrying conductor length and thus the electrical resistance, which, however, must not increase for reasons of efficiency. As a solution to compensate for tolerances during assembly and/or reassembly, in 5 furthermore, in addition to a circular recess 18 for the passage of the screw bolt 4 , an elongated hole 19 is provided as a recess that runs out freely toward an edge of the cell connector 9 . As a result, displacement is possible with a mechanically and electrically secure screw connection. As a result of this design measure, a balancer shaft 17 can be dispensed with, saving material and weight and reducing the electrical resistance.

6a presents a view according to 2 B for the representation of steps of a manufacturing process. After a positioning each one separa th adapter component 1 on a cell pole 5 and the formation of a weld 7, a connector 9 is fixed via the threaded bolt 4 by an arrangement of nuts and washers 10 by applying a tightening torque indicated by the arrows. Even taking into account the measures described above, each of these tightening torques generates mechanical stresses in the area of the weld 7 and thus also at the cell poles 5. To compensate for tolerances and to reduce mechanical stresses during operation through charging and discharging processes and heating of the cells 6 the connector 9 is provided in the center of the balancer shaft 17 with the above technical disadvantages.

6b shows a versus the representation of 6a alternative manufacturing process, which excludes a mechanical effect of the above-mentioned tightening torques in the area of the weld 7 and also on the cell poles 5, at least during manufacture. For this purpose, the adapter components 1 with the connector 9 form a separate subassembly 20 by pre-assembly with fixing by nuts and washers 10. This unit 20 is now placed with the respective bearing surface 2 and the relevant cell poles 5 to form welds 7. An internal flow of forces through the cells 6 is separated by using spacers 14 to largely prevent swelling forces. A material resistance between the cells 6 that is reduced in this way makes a balancing shaft 17 in the cell connector 9 mechanically unnecessary.

Another solution to compensate for tolerances during assembly and/or reassembly is in 7 shown. 7 12 shows a perspective view of a further exemplary embodiment, two separate components 1 being placed on adjacent cell poles 5 again as a prefabricated and preassembled assembly 20 by at least one screw connection on a cell connector 9 and welded. As an alternative to a threaded bolt 4, each of the separate components 1 has a recess for receiving or passing through a screw, through which the cell connector 9 is electrically conductively and mechanically reliably fixed via a screw connection. A balancer shaft 17 can also be omitted here.

Furthermore, each of the additional components 1 here has a bend 21 of approximately 90° between the weld 7 and the area on the separate adapter components 1 designed for screwing to the cell connector 9 . Thus, when loosening or tightening a screw connection, it is spatially pivoted by 90° to the associated weld 7 compared to all other exemplary embodiments experience critical stress. Furthermore, due to improved accessibility, this bend 21 also enables simplified use of a second tool 17 in addition to a screwdriver, which is mechanically grounded to produce a momentary rest, on the adapter component 1. It is not necessary to use a nut beyond the cell connector 9, here Alternatively, a threaded hole is provided in the cell connector 9 for securely manufacturable and detachable fixing of a self-tapping screw 22 while saving one component.

The illustrations of 8a and 8b show plan views of a separate component 1 with different geometries, their welding 7 to an associated cell pole 5. The illustration from 8a shows the structure used so far in all the above-described exemplary embodiments, with the formation of a rectangular weld 7 in the bearing surface 2 with the cell pole 5 underneath 8a 1 shows a modification in that on the additional component 1 a weld 7 is provided as a U-shaped surface or here in the form of a rectangular frame around an element of a screw connection, in the present case a bolt 4. This adaptation of the geometry of the weld seam an increase in the strength of the weld 7 and at the same time a reduction in a possible mechanical load is achieved. Here, in particular, the length of a lever h` on the overall smaller component 1 from a center of the screw bolt 4 to a center of the weld 7 in 8b compared to the embodiment of 8a also significantly shortened with a lever h. As a result, a torque acting on the weld 7 and the cell pole 5 when the screw connection with the cell connector 9 is tightened or loosened is reduced.

9 is a perspective view of a complete module 11 for a high-voltage storage cell, not shown. Using shoulders 13 of a cover of the module housing 12 according to the embodiment of 3b , 4b the separate components 1 are supported and the welds 7 are relieved. In addition, embossings 23 or

Heat caulking of plastic material of the cover of the module housing 12 provided in the area of the cell connector 9 in order to additionally secure the cell connectors 9 of different lengths. Lines 25 in the form of bonding wires run from the cell connectors 9 to a centrally arranged superordinate circuit board 24 on which, among other things, continuous cell monitoring is provided by a BMU. This is an integration of execution tion examples of the present invention as a cell connector in an innovative module.

Not shown in the drawing is a change in local properties with the production of asymmetry against plastic micro-deformations on surfaces by coating the adapter component 1 with a hard layer, such as a Ni protective layer, which also serves as an anti-corrosion layer. The cell connector 9 is left soft and uncoated. A coated contact partner is sufficient to ensure corrosion protection without significantly increasing the electrical resistance of the connection, even when reassembled.

Various approaches to constructing cell connections that can be disassembled and reassembled were described above, which are characterized in that the electrical connection between cell connector 9 and cell pole 5 is designed as a detachable connection via an additional adapter component 1 on a cell pole 5 . Screw loads on weld seams between cell pole 5 and adapter component 1 are significantly reduced or avoided by means of fixed or mobile relief constructions or changes in the properties of the components.

Reference List

1

separate component

2

bearing surface

3

bearing surface

4

fasteners / bolts

5

cell pole

6

elementary electric storage cell

7

welding

8th

friction foil

9

cell connector

10

nut with washers

11

Module composed of several elementary cells 6

12

module housing

13

shoulder

14

Spacers around each of the cells 6 to the cell pole 5

15

pole insert part

16

Tool mechanically grounded to create a momentary rest

17

Balance shaft in the cell connector 9

18

circular recess in the cell connector 9

19

Elongated hole/recess or slot in the cell connector 9 that extends freely towards one edge of the cell connector 9

20

prefabricated / pre-assembled assembly

21

deflection

22

sheet metal screw

23

Stamping of plastic in the area of the cell connectors 9

24

parent circuit board

25

line / bonding wire

Fn

normal force

Mrs

friction force

uhhh

Lever from bolt 4 to weld 7

QUOTES INCLUDED IN DESCRIPTION

This list of documents cited by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent Literature Cited

• DE 102018204346 B3 [0004]
• EP 2506358 B1 [0005]
• DE 102012222712 A1 [0006]
• US5942353A [0008]
• DE 202006018313 U1 [0009]

Claims (10)

Electrical connecting device as a connection between cell poles or connections of individual cells of an energy store, characterized in that a separate component (1) is connected to the respective cell pole (5), preferably by welding (7), the separate component (1) is a detachable part of the cell connector (9) as an adapter. Electrical connecting device according to the preceding claim, characterized in that the separate component (1) is designed as an element of a screw connection with or on the electrical connecting device. Electrical connecting device according to the preceding claim, characterized in that the separate component (1) carries a threaded bolt (4) as an element of a screw connection. Electrical connection device according to one of the preceding claims, characterized in that the separate component (1) has a recess for receiving or passing through a screw or screw connection. Electrical connecting device according to one of the preceding claims, characterized in that the separate component (1) is part of a preassembled assembly (20) which has at least one screw connection. Electrical connection device according to the preceding claim, characterized in that a connector (9) in the region of the screw connection has an elongated hole (19) or a recess which runs out freely towards an edge. Electrical connecting device according to one of the preceding two claims, characterized in that the additional component (1) is designed as a welded stud with a thread or the additional component (1) is designed as a welding lip, which is designed as a connector and in an insert preferably by a Screw connection is secured to or with the connector (9). Electrical connection device according to one of the preceding claims, characterized in that a weld (7) is provided on the additional component (1) in the form of a U-shaped surface or in the form of a rectangular frame around an element of a screw connection. Electrical connection device according to the preceding claim, characterized in that the additional component (1) has a bend (21) between the weld (7) and the area designed for a screw connection. Electrical connecting device according to one of the preceding claims, characterized in that on the additional component (1) a torque support adapted to an external tool (16) and / or to a cover of a module housing (12), a spacer (14), a pole insert part (15) or another frame of the electrical storage cell (6) is provided.

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