DE102019001893A1 - Method for producing electrical connections of at least two battery cells for a battery of a motor vehicle, in particular of a motor vehicle - Google Patents

Abstract

The invention relates to a method for producing electrical connections of two battery cells for a battery of a motor vehicle, comprising: arranging two contact elements (10, 12) formed of a metallic material in mutual overlap such that a first partial area (T1) of a first surface (T1) 14) of a first of the contact elements (10, 12) bears against a second partial area (T2) of a second surface (16) of the second contact element (12) and adjoins the first partial area (T1) and obliquely to the first and second partial areas (T1, T2) extending third portion (T3) of the first surface (14) overlaps a fourth portion (T4) of the second surface (16) adjacent to the second portion (T2) and spaced from the fourth portion (T4); and irradiating a laser beam (24) between the third and fourth partial regions (T3, T4) such that the laser beam (24) extends advantageously obliquely to the first and second partial regions (T1, T2), whereby the contact elements (10, 12) of the laser beam (24) are welded together and thereby electrically connected to each other.

Description

The invention relates to a method for producing electrical connections of at least two battery cells for a battery of a motor vehicle, in particular of a motor vehicle.

The EP 3 109 925 A1 discloses a battery module and a battery having such a battery module. From the US 2010/0247992 A1 For example, a secondary battery and a method of manufacturing such a secondary battery are known. The US 2011/0195288 A1 discloses a battery and a method of manufacturing such a battery. Of the DE 10 2008 059 963 A1 is a method for producing a single cell for a battery to be known as known. Moreover, from the EP 2 372 814 A2 a secondary battery and a secondary battery module are known.

The object of the present invention is to provide a method by means of which battery cells of a battery for a motor vehicle can be electrically connected to one another in a particularly advantageous manner.

This object is achieved by a method having the features of patent claim 1. Advantageous embodiments with expedient developments of the invention are specified in the remaining claims.

In the method according to the invention for the production of electrical connections of at least two battery cells for a battery of a motor vehicle, in particular of a motor vehicle, two contact elements formed from a respective metallic material are arranged in mutual overlapping or overlapping such that a first portion of a first surface of a first of the contact elements at a second portion of a second surface of the second contact element, in particular flat, is applied. Thus, the first portion and the second portion touch each other. In addition, the contact elements are arranged in mutual overlap so that at least one adjoins the first portion and obliquely to the first portion and obliquely to the second portion extending third portion of the first surface overlaps a subsequent to the second portion fourth portion of the second surface and spaced from the fourth portion. As a result, an intermediate space or a gap, in particular an air gap, is formed between the third subregion and the fourth subregion, wherein the interspace or the gap is delimited in a first direction by the third subregion and a second direction opposite to the second direction by the fourth subregion or will. This means that the third subarea and the fourth subarea do not touch each other.

Then, a laser beam is irradiated into the intermediate space or into the gap and thus between the third partial area and the fourth partial area such that the laser beam or its longitudinal extension direction advantageously extends obliquely to the first partial area and obliquely to the second partial area. The first subregion and the second subregion extend, for example, in particular in that they touch one another, in a common first plane. In this case, the laser beam is introduced in the intermediate space such that the laser beam or its longitudinal extension direction advantageously extends obliquely to the first plane. It is conceivable that the third subregion extends in a second plane, which runs obliquely to the first plane. Alternatively or additionally, the fourth subregion may extend in a third plane, which coincides with the first plane or extends obliquely to the first plane. In this case, the third plane can run obliquely or perpendicular to the second plane.

By irradiation of the laser beam is the gap for the preparation of the electrical connection of the battery cells, the contact elements by means of the laser beam welded together and thereby electrically connected to each other. For this purpose, the laser beam strikes, for example, in particular simultaneously, on the contact elements. As a result, the contact elements are heated by means of the laser beam and thereby in each case at least partially melted, in particular in a welding zone. In other words, the respective metallic material of the respective contact element is heated by means of the laser beam and thereby melted, so that the molten materials of the contact elements in the weld zone can mix with each other. As a result, the contact elements are welded together and thus mechanically and cohesively connected to each other. In addition, thereby the contact elements are electrically connected to each other, whereby the battery cells are electrically connected to each other.

The invention thus also includes a component and welding arrangement which comprises the contact elements arranged in the manner described above relative to one another and subsequently welded together. In other words, said component and welding arrangement is produced by the method according to the invention. The invention is based in particular on the following findings: The uniform, in particular electrical, contacting of battery cells For example, designed as electric vehicles motor vehicles is highly complex and of great importance, since on the resulting resistors, the current is set. From different contacts eventually different resistances result at the junctions and thus different electrical currents. The contacting of the individual cells is usually made art alien between copper and aluminum materials or equivalent between copper or aluminum materials in different thicknesses, so that when welding a favorable mixing ratio of the respective elements is ensured. Furthermore, it is in some cases to ensure that no penetration occurs at the lower joining partner. Especially with joining partners of different thickness, this presents an enormous challenge.

The invention now makes it possible to produce the component and welding arrangement in a particularly simple and tailored manner. In other words, the invention describes the method and said component and welding arrangement for a laser welding process, in which the contact elements are welded together in the manner described and thereby electrically connected to each other. In the method, due to the generation of the gap described in comparison to conventional I-seams at a lap joint can be welded very controlled, in particular by the fact that the laser beam is advantageously radiated obliquely to the first plane and thus at an angle of incidence into the gap. The angle of incidence is an angle that the laser beam encloses with the first plane, the angle being greater than 0 degrees and less than 90 degrees. In particular, the method according to the invention makes it possible to weld the contact elements to one another in a particularly simple and secure manner, even if the contact elements have mutually different wall thicknesses or wall thicknesses.

The aforementioned gap between the third subregion and the fourth subregion is also referred to as joint gap, since the contact elements are welded together at the joint gap or in the area of the joint gap and thereby joined together. In this case, the method according to the invention makes it possible to adapt the contact elements, in particular their geometries, to a specific or needs-based adaptation in order to produce the joint gap. For example, the third subregion is produced by mechanical processing, in particular by chamfering, such that the third subregion extends obliquely to the first subregion. In other words, for example, the third partial region is produced by producing a phase of the first contact element. By means of mechanical processing, a wall thickness or material thickness of the first contact element present in an initial state and thus prior to the mechanical processing is thus changed, in particular reduced, in order thereby to produce the third subregion.

• - günstiges Durchmischungsverhältnis der Kontaktelemente beziehungsweise der Werkstoffe und damit gute elektrische Kontaktierung
• - Flexibilität gegenüber Bauteilen und deren Anzahl und Anordnung
• - hohe Prozessstabilität
• - Risiko einer Durchschweißung wird erheblich gesenkt, da das Verfahren deutlich kontrollierbarer als herkömmliche Verfahren ist

Furthermore, it is conceivable that the third subregion is produced by reshaping, in particular by bending, in such a way that the third subregion runs obliquely to the first subregion. This makes it possible, for example, for the first contact element to have the same material thickness or wall thickness, that is to say a constant material thickness or wall thickness, at least in the first subregion and in the third subregion. The above-mentioned angle of incidence is also referred to as the lateral angle, under which is selectively welded into the gap. This is similar to making a fillet weld and is made instead of a conventional I-seam on the lap joint, whereby the contact elements can be particularly advantageous welded together. In particular, it can be avoided by the method according to the invention that the respective contact element is welded through. For example, the contact elements are welded together by the inventive method to produce at least or exactly one weld, wherein the weld is made or formed for example in the gap. In this case, the method according to the invention makes it possible to connect the contact elements with one another by forming at least or exactly one continuous weld seam, so that the contact elements can be connected to one another in a timely and cost-effective manner, and particularly firmly. In particular, the method according to the invention has the following advantages:

• - Favorable mixing ratio of the contact elements or materials and thus good electrical contact
• - Flexibility to components and their number and arrangement
• - high process stability
• - The risk of penetration is considerably reduced because the process is significantly more controllable than conventional processes

In particular, it can be realized by the method according to the invention that the bonding and contacting of the contact elements by welding, in particular by laser welding, of the metallic materials, the angle of incidence and an angle which includes the third portion with the first portion, and not the material thickness of the Contact elements depends. As a result, the contact elements can be reliably connected to one another.

The gap is also referred to as a groove, which is formed for example by folding or chamfering at least the third portion and / or the fourth portion. If, for example, both the second plane and the third plane run obliquely to the first plane, a particularly large overall angle can be created, which the second plane and the third plane enclose with each other, wherein a respective single angle, the second plane or the third plane with includes the first level, can be kept low. As a result, the channel can be made particularly easy. A large overall angle makes it possible to radiate the laser beam particularly easily into the channel. By the feature that the third subregion is produced by mechanical processing, in particular by chamfering, it is to be understood that material removal occurs by which the third subregion is produced accordingly. The fourth subregion, for example, remains flat and in the first plane or is also made obliquely to the first plane.

Since the first subarea and the second subarea lie against one another, in particular flat, the first subarea and the second subarea are also referred to as contact surfaces. It is conceivable that the contact surfaces have the same size, so that the two contact surfaces cover exactly and the groove also has the same or similar dimensions of the edges. Alternatively, the one contact surface, preferably the flat or non-beveled contact surface, be made larger than the other, so that the contact surface rests with the oblique edges on the larger contact surface and only a part of these covers. Here, the welding and thus the contacting take place in the channel, so that the supernatant on one side of the channel is irrelevant.

Preferably, a lateral welding of the contact elements in the groove on both sides, that is, on both sides of the first and second portion and thus the contact surfaces provided to generate both the mechanical and the electrical connection between the contact elements over a particularly large length or area can , By connecting the contact surfaces as arresters or electrodes with a battery cell at least one side is already connected, so that not only the two side surfaces can serve for welding, but also the third side of the contact surface, opposite the respective battery cell, by an oblique edge welded according to the sides.

Further advantages, features and details of the invention will become apparent from the following description of preferred embodiments and from the drawing. The features and feature combinations mentioned above in the description as well as the features and feature combinations mentioned below in the description of the figures and / or in the figures alone can be used not only in the respectively specified combination but also in other combinations or in isolation, without the scope of To leave invention.

• 1 eine schematische Darstellung eines erfindungsgemäßen Verfahrens gemäß einer ersten Ausführungsform;
• 2 eine weitere schematische Darstellung des Verfahrens; und
• 3 eine schematische Darstellung einer zweiten Ausführungsform des Verfahrens.

The drawing shows in:

• 1 a schematic representation of a method according to the invention according to a first embodiment;
• 2 a further schematic representation of the method; and
• 3 a schematic representation of a second embodiment of the method.

In the figures, the same or functionally identical elements are provided with the same reference numerals.

Based on 1 In the following, a first embodiment of a method for electrically connecting at least two battery cells (not shown in the figures) for a battery of a motor vehicle will be explained. The motor vehicle thus comprises, in its completely manufactured state, the battery, which is preferably designed as a high-voltage battery (HV battery) and whose battery cells are electrically connected to each other when the battery is completely manufactured. The motor vehicle is designed as a hybrid or electric vehicle and comprises at least one electric machine, by means of which the motor vehicle can be electrically driven. For this purpose, the electric machine is supplied with stored in the battery and thus in the battery cells electrical energy.

At a first step S1 of the method become two contact elements formed from a respective metallic material 10 and 12 , By means of which the battery cells are electrically connected to each other, arranged in mutual overlap or overlap such that a first portion T1 a first surface 14 of the contact element 10 at a second subarea T2 a second surface 16 of the contact element 12 , in particular flat, is applied. Also, be the first step S1 the contact elements 10 and 12 so arranged in mutual overlap or overlap, that respective, to the first subarea T1 subsequent and oblique to the first subarea T1 and obliquely to the second portion T2 running third sections T3 the surface 14 respectively, to the second subarea T2 subsequent fourth sections T4 the surface 16 overlap and from the respective fourth sub-areas T4 are spaced. As a result, between the respective, mutually overlapping portion T3 and T4 a gap also called gutter or joint gap or gap 18 formed into one by an arrow 20 illustrated first direction through the respective subarea T3 and in one of the first direction opposite and by an arrow 22 illustrated second direction through the respective subregion T4 is limited.

As in synopsis with 2 recognizable, becomes in a second step S2 of the method at least or exactly one laser beam 24 in the gap 18 and thereby between the respective subareas T3 and T4 so irradiated that the laser beam 24 or by a solid line 26 illustrated longitudinal extension direction advantageously obliquely to the sub-areas T1 and T2 runs. As a result, the contact elements for electrically connecting the battery cells 10 and 12 by means of the laser beam 24 , especially in the gap 18 , welded together and thus electrically connected.

Especially good 1 it can be seen that in the interspace 18 which, for example, in the circumferential direction of the contact elements 10 and 12 at least partially, in particular at least predominantly or completely, circulates, preferably uninterrupted and, for example, at least partially, in particular at least predominantly or completely, in the circumferential direction of the contact elements 10 and 12 circumferential weld 28 manufactured, by means of which the contact elements 10 and 12 welded together and thus mechanically and electrically connected to each other. The subareas T1 and T2 run in that they lie flat against each other, in a first level. The respective subarea T3 extends in a respective second plane, which with the first plane an angle α includes. The angle α is greater than 0 degrees and less than 90 degrees. The respective fourth subarea T4 may run in a third plane, which coincides with the first plane or extends obliquely to the first plane.

In 2 is the level normal of the first level designated 30. It is off 2 recognizable that the laser beam 24 or its longitudinal extension direction advantageously obliquely to the sub-areas T1 and T2 and thus obliquely to the first plane, so that the laser beam 24 or its longitudinal extension direction with the first plane or with the plane normal 30 a second angle β includes. It is β greater than 0 degrees and less than 90 degrees. Preferably, it is provided that the angle α greater than the angle β and less than 90 degrees. Besides, it is off 1 and 2 recognizable that the weld 28 not in the first plane or parallel to it, but the weld 28 is also angled.

The laser beam 24 becomes in a Einstrahlrichtung in the intermediate space 18 irradiated, wherein based on this emission direction, the contact element 10 above the contact element 12 is arranged. Thus, the contact element 10 an upper contact element while the contact element 12 a lower contact element. One of the contact elements 10 and 12 For example, is formed of aluminum or copper, wherein the other contact element 12 respectively 10 also made of aluminum or copper. For example, the contact element is present here 10 made of aluminum and the contact element 12 made of copper.

Out 1 It can also be seen that the contact element 10 a first wall thickness or first wall thickness, which is also referred to as a first material thickness, wherein the first material thickness comprises t1 is designated. The contact element 12 has a second material thickness t2 which is also referred to as second wall thickness or second wall thickness. Here is the material thickness t1 constant. Alternatively or additionally, the material thickness t2 constant. In the first embodiment, for example, experiences the upper contact element under the constant material thickness t1 a fold, in particular by bending or another method, whereby the angle α arises or is formed.

3 illustrates a second embodiment in which the angle α by mechanical, in particular machining, and thereby, for example, by material removal of the contact element 10 will be produced. In this case, the contact element 10 in the subarea t1 the first material thickness t1 on, which in the second embodiment over the subregions T1 and T3 of the contact element 10 considered not constant, in contrast to the first embodiment. Bending and machining are component adjustments to realize the angle a. Both in the first embodiment and in the second embodiment, the component adaptation generates in combination with the lower contact element and in particular in the clamped state of the contact elements 10 and 12 the trained as a local joint gap gap 18 at the angle a. For example, the contact elements 10 and 12 after the first step S1 and before the second step S2 clamped together and thus held together. The respective component adaptation can refer to the contact elements 10 and 12 only on the contact element 10 , only on the contact element 12 or on both contact elements 10 and 12 be made. Also compounds of several components, such as so-called Dreiblechverbindungen can be prepared by the process.

The contact elements 10 and 12 can now by means of the laser beam 24 be welded together. Unlike conventional methods, this is not done under vertical beam incidence, but the laser beam 24 falls below the angle called the angle of incidence or lateral angle β into the joint gap. Preferably, the angle β smaller than the angle called a component angle a. Another very positive result is the homogeneous contacting of the contact elements resulting from the controllable welding 10 and 12 , The welding process can be performed by the described arrangement without a filler material and requires no change from conventional equipment technology. In addition, through-welding of the contact elements 10 and 12 safely avoided.

LIST OF REFERENCE NUMBERS

10

contact element

12

contact element

14

surface

16

surface

18

gap

20

arrow

22

arrow

24

laser beam

26

solid line

28

Weld

30

plane normal

t1

material thickness

t2

material thickness

T1

subregion

T2

subregion

T3

subregion

T4

subregion

α

angle

β

angle

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been 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.

Cited patent literature

• EP 3109925 A1 [0002]
• US 2010/0247992 A1 [0002]
• US 2011/0195288 A1 [0002]
• DE 102008059963 A1 [0002]
• EP 2372814 A2

Claims (5)

Method for producing electrical connections of at least two battery cells for a battery of a motor vehicle, comprising the steps of: Arranging two contact elements (10, 12) formed of a respective metallic material in mutual overlap such that a first subregion (T1) of a first surface (14) of a first of the contact elements (10, 12) adjoins a second subregion (T2) a second surface (16) of the second contact element (12) bears against and at least one third partial region (T3) of the first surface (14) adjoining the first partial region (T1) and running obliquely to the first and second partial regions (T1, T2). a fourth partial area (T4) adjoining the second partial area (T2) overlaps the second surface (16) and is spaced from the fourth partial area (T4); and - Injection of a laser beam (24) between the third and fourth partial area (T3, T4) such that the laser beam (24) advantageously obliquely to the first and second partial area (t1, T2), whereby for electrically connecting the battery cells, the contact elements ( 10, 12) by means of the laser beam (24) welded together and thereby electrically connected to each other. Method according to Claim 1 , characterized in that the third subregion (T3) is produced by mechanical processing, in particular by chamfering, such that the third subregion (T3) extends obliquely to the first subregion (T1). Method according to Claim 1 , characterized in that the third subregion (T3) is produced by forming, in particular by bending, in such a way that the third subregion (T3) runs obliquely to the first subregion (T1). Method according to one of the preceding claims, characterized in that the contact elements (10, 12) are formed from mutually alien or similar materials. Method according to one of the preceding claims, characterized in that one of the contact elements (10, 12) made of aluminum and the other contact elements (12, 10) is formed of copper.

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