DE102018109384A1 - Battery cell module and method for contacting the battery cells - Google Patents

Abstract

The invention relates to an accumulator cell module 10 consisting of several series and / or parallel connected accumulator cells 1, each having a positive pole 1.1 and a minus pole 1.2, wherein the plus poles 1.1 and the negative poles 1.2 each have at least one Cell connector 2 are electrically conductively connected to each other, wherein the respective cell connector 2 has a Verbinderpolsegment 2.1 with a Kontaktflächenmaß v, wherein the Verbinderpolsegment 2.1 of the cell connector 2 is attached to the respective negative pole 1.2 or the respective positive pole 1.1 by a solder joint 3, wherein the solder joint 3 forms the only electrical contact between the respective cell connector 2 and the respective battery cell 1.

Description

The invention relates to an accumulator cell module consisting of several series and parallel connected accumulator cells, each having a positive pole and a negative pole, wherein the plus poles and the negative poles are electrically conductively connected to each other via at least one cell connector, said the respective cell connector has a connector pole segment with a contact surface dimension v having.

The invention further relates to a method for contacting a plurality of battery cells in series and in parallel, each having a plus pole and a minus pole across a cell connector, the cell connector having a plurality of connector pole segments, the respective connector pole segment having a pole zone on a first top side wherein the positive poles and the negative poles are electrically conductively connected to each other via cell connectors.

From the DE 10 2015 005 529 A1 an energy storage module consisting of several accumulator cells is already known. The battery storage module described should preferably have a low volume weight against the background of the prior art discussed, and thus a maximum power, which is ultimately achieved by a uniform thermal and electrical load on the individual cells. It is therefore proposed to connect the respective cell via a frictional connection with a contact spring, wherein the contact spring is welded to the adjoining baffle plate by means of a laser welding process.

From the DE 20 2017 003 647 U1 is also an energy storage module consisting of several accumulator known. The system described here is also intended to solve the problem of providing the highest possible performance while ensuring low heat generation. For this purpose, it is proposed that the respective cell is connected to the cell connection means by means of a spot welding method, in particular by means of a laser. Preferably, one to three welds are used. The three welding points must be placed at the plus pole in a central area, whereas at the minus pole according to para. 0028 a placement in a central area should be avoided.

Also is from the EP 2 154 740 A2 a battery storage module consisting of several accumulator known. The memory module described here should be as stable as possible, the stability in turn is defined by the weakest link, thus the respective connection of the respective cell. Furthermore, the problem is to be solved that the battery inside is not too hot due to the heat of its own. In addition, manufacturing tolerances in the production of the battery cells to be met. The solution proposes either welding or brazing the copper-formed cell connectors and associated terminals. The cell connectors themselves are merely positively biased against the respective cell pole. A cohesive connection is not provided.

On the other hand, the present invention has the object, an accumulator cell module and a corresponding manufacturing method such form and order that the strongest possible connection between the cell connector and the respective accumulator cell on the one hand and the best possible contact, thus a low contact resistance between the respective accumulator cell and the Cell connector is guaranteed.

The object is achieved in that the connector pole segment of the cell connector is attached to the respective negative pole or the respective positive pole by a solder connection, wherein the solder connection forms the only electrical contact between the respective cell connector and the respective battery cell.

• - wobei der Zellverbinder mit dem Verbinderpolsegment gegen den zu kontaktierenden Minus-Pol oder Plus-Pol gehalten wird,
• - wobei zwischen dem Verbinderpolsegment und dem zu kontaktierenden Minus-Pol oder Plus-Pol Lot vorgehalten wird,
• - wobei die Polzone mittels eines Laserstrahls erwärmt wird, bis das Verbinderpolsegment auf einer Unterseite mindestens eine Temperatur S aufweist, ab der das Lot schmilzt,
• - wobei eine Oberflächentemperatur O des jeweiligen Minus-Pols oder des jeweiligen Plus-Pols überwacht wird und ein Wärmeeintrag des Lasers derart begrenzt wird, dass die Oberflächentemperatur O einen vorgegebenen Grenzwert G nicht überschreitet. Die Oberflächentemperatur O wird vorzugsweise kontaktlos erfasst. Der Grenzwert für G liegt bei etwa 60°C. Der Laser wird zwecks Begrenzung des Wärmeeintrags abgeschaltet. Alternativ zur Oberflächentemperatur O des jeweiligen Minus-Pols oder des jeweiligen Plus-Pols kann auch die Oberflächentemperatur O der Polzone überwacht werden.

Furthermore, the object is achieved in that the connector pole segment of the cell connector is attached to the respective negative pole or the respective positive pole by a solder connection, wherein the solder joint is used as a single electrical contact between the respective cell connector and the respective battery cell and with a Contact cross-sectional area k is equipped

• the cell connector with the connector pole segment being held against the minus pole or plus pole to be contacted,
• wherein solder is held between the connector pole segment and the minus pole or plus pole to be contacted,
• - Wherein the pole zone is heated by means of a laser beam until the connector pole segment on a bottom at least one temperature S from which the solder melts,
• - where one surface temperature O the respective negative pole or the respective plus pole is monitored and a heat input of the laser is limited so that the surface temperature O a predetermined limit G does not exceed. The surface temperature O is preferably detected contactless. The limit for G is about 60 ° C. The laser is switched off to limit the heat input. Alternative to the surface temperature O of the respective negative pole or the respective plus pole can also the surface temperature O the pole zone are monitored.

In the foreground is the problem that in the cohesive contacting an accumulator cell due to the melting of the metal is accompanied by a relatively large heat input. The accumulator cell inside may, however, usually not be heated above 60 ° C, otherwise this will be permanently damaged. Therefore, a connection method with very limited heat input must be used. Against this background, connection methods known from the prior art are known which ensure a very limited heat input. As an alternative to the mechanical, thus non-positive contact between battery cell and cell connector, the spot welding is called. Spot welding has the great advantage that the welding point itself can be kept very small and thus also the associated specific heat input per spot weld in the cell. However, due to the interior design of the cell at the minus pole, placement of spot welds in a central area is to be avoided.

With regard to the heat balance of an accumulator cell or the accumulator cell module, it has been found by the applicant that such a spot welded joint has a relatively small contact cross-sectional area and thus a relatively high electrical resistance. This electrical resistance has a negative effect on the heat balance, because it justifies a further heating of the accumulator cell module. Accordingly, it would be advantageous if the largest possible contact surface between the battery cell and cell connector is achieved. According to the teaching of the prior art, it is envisaged that up to three welding points are used for joining.

Background of the problem regarding the specific heat input per spot weld is that the heat input proportionally increases with the size of the spot weld, so that the size of the spot weld is limited to about 1 mm ² to 3 mm ² in the previously known Akkumulatorzellengrößen.

According to the invention, a soldering process is now used for this cohesive connection in order to increase the contact cross-sectional area of the contact point. However, the soldering process initially has the supposed disadvantage that it also increases the area to be heated by a multiple, which is accompanied by a disadvantageous increase in the specific heat input per connecting step.

On the other hand, a soldering process, in which the ultimately achieved size of the soldering point does not exceed an aforementioned maximum dimension of 1 mm ² to 3 mm ² , would not be feasible. Because against the background of existing manufacturing tolerances on the one hand and the available Lotdosierungsdüsen no process reliability can be achieved. The contact surfaces to be connected would have to be extremely precise and expensive in order to ensure a desired solder distribution and the said contact cross-sectional area of the solder contact of 1 mm ² to 3 mm ² . Accordingly complex would be the arrangement of three solder points of this size.

According to the invention, however, this problem can be solved by using a laser to heat the soldering spot. In this way, the necessary heat input both spatially and temporally extremely precisely defined to ultimately not exceed the critical Akkumulatorzellentemperatur despite ensuring much larger contact cross-sections.

It has also been found that the use of solder has the following advantages. While in resistance welding, the two contacts to be connected are heated simultaneously, the cell connector is first heated in the soldering process according to the invention, on the other hand, first the solder is heated. The Akkumulatorzellenpol is in the heating chain at the end, which is accompanied by a reduction of adverse heat input. The solder initially serves as an insulator, so to speak. During the laser welding process, the accumulator cell pole is likewise directly exposed to the necessary process heat, because the heat input into the accumulator cell pole takes place directly through the laser beam after it has melted through the cell connector. An initial heat conduction from the acted upon by the laser beam cell connector to the Akkumulatorzellenpol is negligible.

During soldering, the specific heat input into the solder is the greatest, because this must melt, thus changing the state of aggregation from solid to liquid. That's just not the case with welding. Both contact partners must be melted.

It may also be advantageous for this purpose if the solder joint has a contact cross-sectional area k which is accompanied by a significant reduction of the electrical resistance of the solder joint, wherein for the contact cross-sectional area k the following condition applies:
Amine <= k <= Amax, with
Amin = value of the value group
{7 mm ² ; 13 mm ² ; 30 mm ² ; 50 mm ² ; 80 mm ² ; 150 mm ² } and Amax = value from the value group {p; v}.

By applying a contact cross-sectional area k of at least 7 mm ² , the associated electrical resistance is reduced, which is accompanied by a significantly lower temperature during operation. It can even be assumed that the soldering spot of the contact will be cooler overall than the accumulator cell itself.

Furthermore, it may be advantageous if the connector pole segment of the cell connector has at least one recess in the edge region, by means of which a temperature of the respective pole can be detected. The recess ensures direct access to the respective pole of the battery cell in order to determine the temperature of the pole during the soldering process. In addition, the conductor cross-section between the connector pole segment and the remaining cell connector is reduced, so that during the soldering process, less heat dissipation from the connector pole into the remaining cell connector takes place.

It may also be advantageous if the cell connector has a top side and on the top side in the region of the connector pole segment a pole zone, wherein at least the pole zone has a roughening, a satin finish and / or a coating which causes a reduced reflection. In particular, by applying a coating can be maximized in a simple way, the emissivity of the surface, so that it is to settle only slightly below 1 at best. This is achieved mainly by using a black paint, which is at best matte finished.

It may be advantageously provided that the respective pole has a surface and the cell connector has a bottom, wherein the surface and / or the underside is roughened at least in the region of the connector pole segment. By roughening the surface of the pole or the bottom of the cell connector improved adhesion to the solder is achieved.

Of particular importance may be for the present invention, when the connector pole segment is formed as a plate-like shape and a raised cell connector pole with the contact surface dimension v formed. Due to the plate-shaped shape manufacturing tolerances can be compensated very well in the context of storage or the housing. In addition, the solder distribution during the soldering process is favored, because the gap between the battery cell and the cell connector is limited to the connector pole segment.

In connection with the design and arrangement according to the invention, it can be advantageous if the cell connector pole protrudes by 0.3 to 1.9 mm or 0.8 to 1.4 mm relative to the underside. A supernatant of about 1.1 mm has proved to be advantageous.

It can also be advantageous if the cell connector is formed from copper, brass or aluminum. Copper has proved to be very advantageous, because it ensures excellent heat conduction, thus ensuring uniform heat distribution within the cell connector.

Furthermore, it may be advantageous if the connector pole segment has a recess, by which the temperature of the respective negative pole or of the respective plus pole is determined. The temperature detection is preferably carried out contactless, such as by a pyrometer or other temperature measuring devices. By providing the recess, the pole temperature can be detected directly, thus ensuring short reaction times, and consequently a reproducible and faster connection or contacting process.

By applying the biasing means, a secure positioning of the cell connector can be ensured.

Finally, it may be advantageous if a laser head is provided with a laser head drive, by means of which the laser head in the directions x . y . z is moved, wherein the biasing means is medium or directly attached to the laser head drive and simultaneously with a focusing movement of the laser head in the direction z the biasing means is applied against the cell connector. At the same time in the focusing movement not only the biasing means but at best the pyrometer can be brought into position. Thus, the positioning of all three aforementioned elements is achieved by an adjustment.

It may also be advantageous for this purpose if the cell connector and the accumulator cell during the soldering operation against a relative movement in one direction x and one direction y be secured. The securing of the cell connector can be achieved additionally or alternatively to the biasing means by force or positive connection. Conceivable here are, for example, a Lochstiftmuster, via which the cell connector with the accumulator cell or an accumulator cell receptacle is in communication.

Furthermore, it may be advantageous if a viscous solder is used, which is applied in droplets to the respective pole such that the solder by placing the cell connector on the Verbinderpolsegment and the respective pole is distributed within the resulting gap, wherein the respective pole in the region of a recess is kept largely free of solder. The solder is dosed in the high-viscosity state and placed with respect to the connector pole segment such that when the connector pole segment is applied against the respective pole, a uniform distribution of the solder within the gap occurs. This is accompanied by an optimal distribution of the solder.

• 1 eine Prinzipskizze eines Zellverbinders mit Akkumulatorzellen;
• 2 eine Prinzipskizze der Akkumulatorzelle;
• 3a einen Zellverbinder in der Ansicht von oben;
• 3b der Zellverbinder nach 3a in der Ansicht von unten;
• 4 eine Prinzipskizze der Seitenansicht einer Akkumulatorzelle mit endseitig angeordneten Zellverbindern;
• 5 einen Ausschnitt der Polzone mit Kontaktquerschnittsfläche k;
• 6 eine Prinzipskizze der Lötvorrichtung mit Akkumulatorzelle und Zellverbinder;
• 7 ein Akkumulatorzellenmodul.

Further advantages and details of the invention are explained in the patent claims and in the description and illustrated in the figures. It shows:

• 1 a schematic diagram of a cell connector with accumulator cells;
• 2 a schematic diagram of the battery cell;
• 3a a cell connector in the top view;
• 3b the cell connector after 3a in the view from below;
• 4 a schematic diagram of the side view of an accumulator cell with end-mounted cell connectors;
• 5 a section of the pole zone with contact cross-sectional area k ;
• 6 a schematic diagram of the soldering device with accumulator cell and cell connector;
• 7 an accumulator cell module.

An accumulator cell module 10 consists of several accumulator cells 1 that via so-called cell connectors 2 be electrically connected. In the cell connector 2 It is a metal sheet, which in the range of different pole zones 2.3 with a plus or minus pole 1.1 . 1.2 an accumulator cell 1 is electrically connected.

The respective accumulator cell 1 points as in 2 represented a plus pole 1.1 and an opposing minus pole 1.2 on, with the respective plus or minus pole 1.1 . 1.2 over the respective surface 1.3 with the pole zone 2.3 of the cell connector 2 is connected. The respective pole 1.1 . 1.2 has a Kontakflächemaß p on which of the surface of the respective pole 1.1 . 1.2 equivalent.

To 1 has the cell connector 2 for each pole to be connected 1.1 . 1.2 a pole zone 2.3 in which a connector pole segment 2.1 of the cell connector 2 is designed as Zellverbinderpol, here in the form of a molding, which with the respective pole 1.1 . 1.2 is electrically connected. The cell connector 2 is with the cell connector pole 2.1 against the respective plus or minus pole 1.1 . 1.2 the accumulator cell 1 brought to the plant and soldered as described further below for the purpose of contacting and fastening. To manufacture this solder joint, the cell connector 2 in the area of the pole zone 2.3 or in the region of the cell connector pole 2.1 a recess 2.2 on. The cell connector pole 2.1 has a contact surface dimension v on which of the circular shape of the Zellverbinderpols 2.1 corresponds less the area of the recess 2.2 ,

In exemplary embodiment 3a is the cell connector 2 shown in the view from above. The respective connector pole segments or cell connector poles 2.1 are on the top 2.4 imprinted, wherein the recess 2.2 in the cell connector pole 2.1 is provided. In addition, the Zellverbinderpol 2.1 with a dark coating 7 provided so that its emissivity in terms of heat absorption or the heat input into the Zellverbinderpol 2.1 is maximized. The sheet-shaped cell connector 2 indicates complementary to the different pole zones 2.3 several recesses 2.5 between the different pole zones 2.3 for the purpose of saving material and weight.

To 3b , upper half is the bottom 2.6 of the cell connector 2 shown. There is the respective cell connector pole 2.1 or the pole zone 2.3 to be seen from below. Within the respective pole zones 2.3 is the cell connector pole 2.1 formed as part of the shaping including the recess 2.2 within the cell connector pole 2.1 ,

According to execution example 3b The lower half of the picture can be used as an alternative to the one recess 2.2 also several recesses 2.2 within the cell connector pole 2.1 be provided.

As already stated, the respective accumulator cell 1 at the respective plus pole 1.1 or the minus pole 1.2 via a corresponding cell connector 2 contacted. This is between the cell connector 2 and the respective pole 1.1 . 1.2 by solder a solder joint 3 brought in. After heating the solder and then cooling arise between the respective pole 1.1 . 1.2 and the respective cell connector 2 or its cell connector pole 2.1 a solid, good electrical connection with a correspondingly large contact cross-sectional area k ,

To 4 is the solder connection 3 For the sake of clarity, the thickness is exaggerated. In fact, the cell connector 2 with the respective cell connector pole 2.1 or its pole zone 2.3 against the respective plus or minus pole 1.1 . 1.2 the accumulator cell 1 brought to the plant with prior dosing of liquid solder on one of the surfaces to be brought into contact. The lot is distributed 3 within the resulting gap between both surfaces. This is according to 5 outlined. The cell connector 2 points in the area of its pole zone 2.3 the cell connector pole 2.1 on, which is formed as mentioned as a molding. The cell connector pole 2.1 has a contact surface dimension v on, with the exception of the recess 2.2 the circular area dimension of the circular cell connector pole 2.1 equivalent. After applying the solder 3 to the respective pole 1.1 . 1.2 or the respective underside 2.6 of the cell connector pole 2.1 and then against each other applying cell connectors 2 and accumulator cell 1 the lot is distributed 3 in the resulting gap and forms according to the metered Lotmenge ultimately a contact cross-sectional area k out. With a further increase in solder quantity, the contact cross-sectional area correspondingly becomes k enlarge. A leakage of the solder 3 in the area of the recess 2.2 is to be excluded at first, as long as further shares of Kontaktflächenmaßes v of the cell connector pole 2.1 still from Lot 3 are kept free. The recess shown here 2.2 has a diameter a of about 3 mm.

To 6 is shown a soldering device in principle consisting of a laser head 5 , a laser head drive 5.1 as well as one on the laser head 5 arranged pyrometer 6 and a biasing means 4 , After placing the cell connector 2 on the pole 1.1 becomes the laser head 5 with its biasing agent 4 down towards z proceed so that the biasing agent 4 the cell connector 2 against the pole 1.1 invests. Vorab this system is as previously described on the pole 1.1 a quantity of solder to be determined 3 metered, which is already spread in the position shown here within the formed gap or gap. Subsequently, over the laser head 5 and the laser beam producible therewith 5.2 the cell connector pole 2.1 or its top 2.4 heated immediately, so that the heat entered with it also on the solder underneath 3 spreads. About the pyrometer 6 immediately becomes the surface temperature O of the pole 1.1 detected. When reaching a desired limit temperature G the heat input into the cell connector pole 2.1 completed. The lot 3 cools and after reaching the cooling temperature is therefore not only solid but also large-area electrically conductive solder joint 3 between the cell connector 2 and the accumulator cell 1 reached. The cell connector 3 regardless of the bias in the direction z through the biasing element 4 also in the direction of the other two spatial axes x . y like after 3a can be fixed during the soldering process to prevent relative movement during the soldering process. This fixation, especially in the direction x . y , can also be done by applying a positive connection between the cell connector 2 and an accumulator cell receptacle, not shown, in which the accumulator cells 1 are stored.

To 7 is stylized represented an accumulator cell module 10 consisting of several accumulator cells 1 , which are mounted on a receptacle, not shown. The accumulator cell module 10 is to be supplemented by said cell connector 2 such as for two cells, for example 1 shown. The number of accumulator cells to be connected 1 , hence the size of the cell connector 2 and the number of cell connector poles 2.1 are the number of accumulator cells to be connected 1 adjust accordingly. The described contacting takes place both for the positive pole shown here 1.1 the accumulator cell 1 as of course also for the not to be seen minus pole 1.2 instead of. The accumulator cells 1 can within such a battery cell module 10 individually and / or groupwise connected in series and / or in parallel.

LIST OF REFERENCE NUMBERS

1

accumulator cell

1.1

Plus pole

1.2

Negative pole

1.3

surface

2

cell connectors

2.1

Connector pole segment, cell connector pole, molding

2.2

recess

2.3

Polzone

2.4

top

2.5

recess

2.6

bottom

3

Solder joint, solder

4

biasing means

5

laser head

5.1

Laser head drive

5.2

laser beam

6

pyrometer

7

coating

10

Akkumulatorzellenmodul

Amin

Minimum of k

A-Pol

Maximum of k

a

Width of 2.2 , Diameter

G

Limit for O [° C]

k

Contact cross section area [mm ² ]

O

Surface temperature [° C]

p

Contact surface dimension [mm ² ] of 1.1 . 1.2

S

Temperature [° C]

v

Contact surface dimension [mm ² ] of 2.1

x

Direction in the Cartesian coordinate system

y

Direction in the Cartesian coordinate system

z

Direction in the Cartesian coordinate system

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

• DE 102015005529 A1 [0003]
• DE 202017003647 U1 [0004]
• EP 2154740 A2 [0005]

Claims (14)

Battery cell module (10) comprising a plurality of battery cells (1) connected in series and / or in parallel, each having a plus pole (1.1) and a minus pole (1.2), the plus poles (1.1) and the minus poles ( 1.2) are each electrically conductively connected to one another via at least one cell connector (2), wherein the respective cell connector (2) has a connector pole segment (2.1) with a contact surface dimension v, characterized in that the connector pole segment (2.1) of the cell connector (2) on the respective negative pole (1.2) or the respective positive pole (1.1) by a solder joint (3) is fixed, wherein the solder joint (3) forms the only electrical contact between the respective cell connector (2) and the respective accumulator cell (1) , Accumulator cell module (10) according to Claim 1 , characterized in that the solder joint (3) has a contact cross-sectional area k, which is accompanied by a significant reduction of the electrical resistance of the solder joint (3), wherein for the contact cross-sectional area k the following condition applies: amine <= k <= Amax, with amine = Value of the value group {7 mm ² ; 13 mm ² ; 30 mm ² ; 50 mm ² ; 80 mm ² ; 150 mm ² } and Amax = value from value group {p; v}. Accumulator cell module (10) according to Claim 1 or 2 , characterized in that the connector pole segment (2.1) of the cell connector (2) has at least one recess (2.2) in the edge region, by which a temperature of the respective pole (1.1, 1.2) can be detected. Battery cell module (10) according to one of the preceding claims, characterized in that the cell connector (2) has a top side (2.4) and on the top side (2.4) in the region of the connector pole segment (2.1) has a pole zone (2.3), wherein at least the pole zone ( 2.3) has a roughening, a satin finish and / or a coating (7), which causes a reduced reflection. Battery cell module (10) according to one of the preceding claims, characterized in that the respective pole (1.1, 1.2) has a surface (1.3) and the cell connector (2) has a bottom side (2.6), wherein the surface (1.3) and / or the Bottom (2.6) is roughened at least in the region of the connector pole segment (2.1). Battery cell module (10) according to one of the preceding claims, characterized in that the connector pole segment (2.1) is designed as a plate-shaped formation and forms a raised cell connector pole 2.1 with the contact surface dimension v. Accumulator cell module (10) according to Claim 6 , characterized in that the Zellverbinderpol (2.1) relative to the underside (2.6) protrudes by 0.3 to 1.9 mm or 0.8 to 1.4 mm. Battery cell module (10) according to one of the preceding claims, characterized in that the cell connector (2) made of copper, brass or aluminum is formed. A method for contacting a plurality of battery cells (1) connected in series and in parallel, each having a plus pole (1.1) and a minus pole (1.2) via a cell connector (2), the cell connector (2) having a plurality of connector pole segments (2.1) in which the respective connector pole segment (2.1) has a pole zone (2.3) on a first upper side (2.4), wherein the positive poles (1.1) and the negative poles (1.2) are electrically conductively connected to each other via the cell connector (2) , characterized in that the connector pole segment (2.1) at the respective negative pole (1.2) or the respective positive pole (1.1) by a solder joint (3) is fixed, wherein the solder joint (3) as a single electrical contact between the respective Cell connector (2) and the respective accumulator cell (1) is applied and provided with a contact cross-sectional area k, - wherein the cell connector (2) with the connector pole segment (2.1) against the negative to be contacted Pole (1.2) or plus pole (1.1) is held, - wherein between the connector pole segment (2.1) and to be contacted negative pole (1.2) or positive pole (1.1) Lot is kept; wherein the pole zone (2.3) is heated by means of a laser beam until the connector pole segment (2.1) has at least one temperature S on a lower side (2.6) from which the solder melts, - a surface temperature O of the respective minus pole (1.2) or the respective plus pole (1.1) is monitored and a heat input by the laser is stopped when the surface temperature O reaches a predetermined limit value G. Method according to Claim 9 , characterized in that the Verbinderpolsegment (2.1) has a recess (2.2), by which the temperature of the respective negative pole (1.2) or the respective positive pole (1.1) is determined. Method according to Claim 9 or 10 , characterized in that a biasing means (4) is provided, by means of which the connector pole segment (2.1) during the soldering medium or directly against the negative pole to be contacted (1.2) or positive pole (1.1) is applied in a direction z. Method according to one of the preceding Claims 9 to 11 , characterized in that a laser head (5) with a laser head drive (5.1) is provided, by means of which the laser head (5) is moved in directions x, y, z, wherein the biasing means (4) middle or directly on the laser head drive (5.1 ) is attached and at the same time with a focusing movement of the laser head (5) in the direction z, the biasing means (4) against the cell connector (2) is applied. Method according to one of the preceding Claims 9 to 12 , characterized in that the cell connector (2) and the accumulator cell (1) are secured during the soldering operation against a relative movement in a direction x and a direction y. Method according to one of the preceding Claims 9 to 13 , characterized in that a viscous solder is used, which is applied in droplets to the respective pole (1.1, 1.2) such that the solder by placing the cell connector (2) on the connector pole segment (2.1) and the respective pole (1.1, 1.2) is distributed, wherein the respective pole (1.1, 1.2) in the region of a recess (2) is kept largely free of solder.

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