DE102022201397A1 - Accumulator, in particular for a motor vehicle - Google Patents

Abstract

The invention relates to an accumulator, in particular for a motor vehicle, with a plurality of electrochemical cells for storing electrical energy, with a plurality of electrochemical cells being combined to form a cell stack (10) and connected by means of a contacting element (16) in the stacking direction (X). the cell stack (10) extends along, are electrically contacted. At least two cell stacks (10) are arranged one behind the other in the stacking direction (X), contacting elements (12) of both cell stacks (10) being electrically connected to one another by an electrical connecting element (14), the connecting element (14) having at least one contacting region (16) a contacting element (12) is electrically connected.

Description

The invention relates to an accumulator according to the preamble of claim 1.

Accumulators of the type in question are used in particular in motor vehicles. They are used there in particular to supply electrical drives for effecting the driving movement of the motor vehicle with electrical energy.

Accumulators of the type in question have a plurality of electrochemical cells for storing electrical energy. The use of a plurality of electrochemical cells makes it possible, on the one hand, to provide high capacities and, on the other hand, also to provide high electrical power. This advantageously qualifies accumulators of the type in question for uses that place corresponding demands on the accumulators, for example use in motor vehicles.

In order to enable such accumulators to be constructed in a compact manner, a plurality of electrochemical cells can be combined to form a cell stack. The cells combined to form the cell stack are then electrically contacted by means of a contacting element which extends along the cell stack in the stacking direction. Such contacting elements are also referred to as busbars. Correspondingly contacted cell stacks are, for example, from U.S. 2020/0212404 A1 or the JP 2012-243689 A known.

A plurality of such stacks are typically arranged in a common protective housing with the stacking directions aligned parallel to one another. In this case, there is typically a desire to utilize the space available in the protective housing as well as possible.

A problem with known accumulators, however, is that the electrochemical cells are subject to changes in volume during charging and/or discharging, which is particularly noticeable in a change in their thickness in the stacking direction. In particular, this limits the number of electrochemical cells that can be combined to form a stack or the dimensions of such a stack in the stacking direction in practice.

Limiting the length of the cell stacks in the stacking direction ultimately also results in corresponding limitations with regard to the achievable dimensions of the protective housing, which can be sensibly exploited by cell stacks arranged parallel to one another.

The invention is therefore based on the object of demonstrating an accumulator in which a larger number of cells can be arranged one behind the other in the stacking direction.

The object is solved by an accumulator with the features of claim 1. The features of the dependent claims relate to advantageous embodiments.

The accumulator has a plurality of electrochemical cells for storing electrical energy. The cells can be pouch cells. Alternatively and/or additionally, they can also be cells that have their own cell housing. In this case, the cell housings can in particular be flat and of a—at least essentially—cuboid basic shape.

In each case, a plurality of the electrochemical cells are combined to form a cell stack. In particular, this can mean that the cells form a unit that can be handled mechanically when the accumulator is assembled. In the cell stack, the plurality of cells are arranged one behind the other in the stacking direction. In this case, the electrodes of the individual cells extend in particular over an area. In this case, the planar extent is oriented in particular perpendicularly to the stacking direction.

The accumulator can have a preferred orientation with a bottom and a top. The preferred orientation is in particular also the orientation in which the accumulator is assembled. The preferred orientation for assembling the accumulator is important and defined by it, particularly when materials are used during assembly of the accumulator which solidify during production, for example materials for filling cavities, such as so-called gap fillers. The stacking direction corresponds in particular to a horizontal direction based on the preferred orientation of the accumulator.

The electrochemical cells combined to form a cell stack are electrically contacted by means of a contacting element which extends along the cell stack in the stacking direction. The electrical interconnection of the cells is ensured via the contacting element. In addition, the contacting element can have secondary functions, for example when combining the cells to form the tent stack. The contacting element extends along in particular with respect to the preferred orientation of the accumulator a vertically oriented side of the cell stack. In this way, the cell stack can be arranged with its underside pointing downwards in relation to the preferred orientation of the accumulator on a base which is provided in particular by the housing of the accumulator. In this case, a cell stack preferably has two contacting elements which extend along the cell stack in the stacking direction along vertical sides of the cell stack which are remote from one another. In this context, the two contacting elements of the cell stack serve in particular to implement the desired interconnection of the individual poles of the individual cells and at the same time to enable contacting of the entire cell stack as an electrical unit.

The object is achieved in particular in that at least two cell stacks are arranged one behind the other in the stacking direction. In this case, contacting elements of both cell stacks are electrically connected to one another by an electrical connecting element. The connecting element in turn is connected to at least one contacting area of a contacting element. The connecting element is preferably connected to two contacting areas of both connected cell stacks.

It has been shown that such an arrangement, in which at least two cell stacks are arranged one behind the other in the stacking direction, allows a sufficient degree of relative movement between the two cell stacks, so that overall a larger number of cells can be arranged along the stacking direction than in the case of a single cell stack. The stacking directions of both cell stacks here run parallel as a common stacking direction.

The connecting element can be connected to the connecting area in particular by means of a screw screwed into a nut. Such a screw connection can establish a reliable electrical contact and at the same time transmit the mechanical forces that arise during relative movements of the cell stacks that are connected to one another. In addition, the production of such a screw connection can generally be easily automated. The axis of the screw can be oriented, at least essentially, perpendicularly to the stacking direction. Such an orientation of the screw enables the process to be well automated, in particular when the screw is screwed into the nut from above in relation to the preferred orientation of the accumulator. This means that, based on the preferred orientation of the accumulator, the axis of the screw is oriented, at least essentially, vertically.

The accumulator preferably has a movable nut receptacle in which the nut can be received and moved into a use position. In the usage position, the screw can be screwed into the nut to connect the connecting element to the contacting area. In other words, this means that the contact area is between the screw, in particular the screw head, and the nut when the nut receptacle is moved into the usage position.

The nut receptacle can be moved into the use position, in particular starting from a receiving position for receiving the nut. The receiving position is selected in particular in such a way that access to the nut receptacle for the purpose of inserting the nut into the nut receptacle is possible, in particular with the receiving of the nut into the nut receptacle not being impeded by the contacting area.

The nut receptacle can in particular be fastened to the contacting element. Preferably, the nut retainer is slidably attached to the contacting member to allow the nut retainer to be moved to the use position. Fastening the nut receptacle to the contacting element has the advantage that the nut receptacle becomes part of a manageable unit with the contacting element and thus with the cell stack.

The nut receptacle can be moved or shifted in particular in the stacking direction. A movement in the stacking direction is particularly suitable for bringing the nut into its position of use, which is located below the contacting area, in particular with regard to the preferred orientation of the accumulator.

In particular, the nut receptacle can be moved out of its position of use back into the receiving position. This makes it possible, in particular, in the event of an incorrect screw connection, to safely remove the screw and the nut, which is typically damaged as part of the implementation of the incorrect screw connection, from the battery housing. A new nut can then be inserted into the nut receptacle and this can be moved back into the use position to enable renewed screwing.

Based on the preferred orientation of the accumulator, the nut receptacle can be closed downwards. This can be realized, for example, in that the nut receptacle is trough-shaped. Such a design of the nut mount allows that Chips, which can arise when screwing attempts fail, are caught inside the nut holder. As a result, the chips do not fall down into the accumulator. The occurrence of short circuits in the accumulator due to such chips can be prevented in this way.

The nut can have an anti-rotation area which interacts with the contacting area in such a way that the nut is prevented from turning when the screw is screwed in. Such an anti-twist device for the screw considerably simplifies the automated screwing of the connecting element to the contacting area. Furthermore, it is advantageous if the nut interacts with the contacting area in this regard. This is of course a comparatively massive area made of a metallic material in order to enable the conduction of the current intensities that occur. The nut receptacle, on the other hand, can be a plastic part. As a plastic part, the nut mount can be manufactured inexpensively and also with a complicated geometry. For example, the nut receptacle can be produced by a plastic injection molding process. Such a nut receptacle is then less well suited to absorbing the forces acting on an anti-rotation area of the nut during screwing than the contacting area.

The anti-rotation area can in particular be designed in such a way that it engages with the contacting area when the nut receptacle with the nut accommodated therein is moved into its position of use. As a result, when the nut receptacle is moved into its position of use, the nut is automatically secured against rotation, without further interventions being necessary for this purpose.

The nut can be a stamped and bent nut. Punched bending nuts have the advantage that they are available inexpensively as standard parts, even in configurations that allow an anti-twist engagement with the contact area.

The contacting area can be a flat metal part that has sections separated from one another by bends and/or developments. In this case, sections of the contacting region extend away from the cell stack, in particular with one of the extension directions of their areal extent in a direction perpendicular to the stacking direction. Sections of the contacting area which are oriented in a planar manner make it possible to a particular extent to compensate for relative movements between the cell stacks connected by the connecting elements. An elastic deformation of the contacting area is made possible by the orientation of the planar extension of the sections of the contacting area. As a result, the connecting element can be made structurally simpler. This means in particular that the connecting element, which must have a significant cross-section for conducting the comparatively high currents, can be made more rigid or more rigid. Relative movements of the cell stacks, which are caused, for example, by changes in the volume of the cells, no longer have to be compensated for by deformations of the connecting element; rather, they can be compensated for by deformations of flat sections of the contacting area.

The contacting area has in particular a connecting area for connecting the contacting area to the connecting element. The connection area is flat and extends in particular with one of the extension directions of its flat extension in the stacking direction. The connection area extends in particular away from the cell stack with another of the directions of extension of its areal extension. In this way, with the preferred orientation of the accumulator, the connecting section provides an upward-pointing contact surface that can be contacted by the connecting element. In particular, the connecting element and the connecting section are screwed together in that the screw used for this is guided through corresponding openings in the connecting element and connecting section and so that the connecting element and the connecting section of the contacting area press against one another.

The contacting region can have a bending section which extends over a surface perpendicular to the stacking direction and which is connected to the connecting section via a first bend and/or angle. Such a bending section serves in particular to bend to compensate for the relative movements between the cell stacks. This is made possible in particular by the orientation of the two-dimensional extension of the bidet section. The bending section extends in particular with one of the extension directions of its areal extent in the vertical direction away from the cell stack. This orientation already minimizes the moment of resistance of the flat bending area against elastic bending in the directions that occur most frequently in cell stacks in accumulators of the type in question. In this case, the areal extent is in particular perpendicular to the stacking direction direction oriented. It has been shown that such an orientation of the bending section is most suitable for compensating for the relative movements of the cell stacks connected by the connecting elements that occur in practice.

The bending section can be connected to a base section via a second bend and/or development. In this case, the contacting area is fastened to the base section on the contacting element. The base section can also extend flatly. The planar extent of the base section is in particular oriented perpendicular to the bending section and/or the connecting section.

The second bend and/or bend is in particular oriented perpendicularly to the first bend and/or development. Such an alignment of the bends and/or bends relative to one another achieves the geometry of the contacting area, with which it is possible to realize a bending behavior that compensates for the relative movements of the stack.

The second bend and/or development may be spaced from the first bend and/or bend such that a gap is formed between the base portion and the bend portion. The gap extends away from the second bend and/or bend in the direction of the connection section. Such a gap allows the flex section to move “more freely” relative to the base section, thereby improving the flexing behavior of the flex section. The distance between the first and the second bend and/or development is preferably greater than half of the total extension of the bending section in the corresponding direction.

• 1 eine schematische perspektivische Darstellung des Verbindens zweier in Stapelrichtung hintereinander angeordneter Zellstapel,
• 2 eine Detaildarstellung eines Bereichs aus 1 mit in die Aufnahmeposition bewegter Mutteraufnahme,
• 3 eine perspektivische Darstellung eines Ausschnitts aus 1 unter Weglassung einzelner Bestandteile,
• 4 eine freigestellte Darstellung eines der Kontaktierungselemente mit einem separierten Kontaktierungsbereich.

Further practical embodiments of the invention are described below in connection with the drawings. Show it:

• 1 a schematic perspective view of the connection of two cell stacks arranged one behind the other in the stacking direction,
• 2 a detailed view of an area 1 with the nut mount moved into the mounting position,
• 3 a perspective view of a detail 1 with the omission of individual components,
• 4 a cropped representation of one of the contacting elements with a separated contacting area.

In 1 two cell stacks 10 are shown by way of example, in each of which a plurality of electrochemical cells are combined to form a cell stack 10 .

The two cell stacks 10 shown by way of example have contacting elements 12 which extend along the cell stacks 10 in the stacking direction X. The contacting elements 12 are in each case flat structures which enable the desired interconnection of the individual cells in the cell stacks 10 to be implemented. The accumulator can have a preferred orientation. In the case of the cells shown by way of example, the preferred orientation of a corresponding accumulator corresponds to an orientation in which the stacking direction X runs in the horizontal. The direction Y, which is shown as an example and is perpendicular to the stacking direction, also runs horizontally in relation to the preferred orientation of the accumulator. The direction Z shown as an example is the vertical direction in relation to the preferred orientation of the accumulator.

The cell stacks 10 arranged one behind the other in the stacking direction X are electrically connected to one another by an electrical connecting element 14 . As in the example shown, the electrical connection element 14 can be electrically connected to contacting regions 16 of the contacting elements 12 .

As shown in the example shown, the connecting element 14 can be connected to the respective contacting area 16 by means of a screw 20 screwed into a nut 18 . Here, the screw 20 is oriented perpendicularly to the stacking direction, in particular as in the case of the two screws 20 shown by way of example. In relation to the preferred orientation of the accumulator, the respective screw 20 was screwed in, in particular from above, as shown.

The accumulator can have a movable nut mount 22 . Two movable nut mounts 22, each of which is assigned to one of the cell stacks 10, are shown as an example.

In the 1 the nut receptacles 22 are shown in their position of use, in which the screws 20 can be screwed in. In 2 one of the nut receptacles 22 is shown as an example, which is moved into its receiving position. As shown by way of example, the nut receptacles 22 can be slidably fastened to the contacting areas 16 .

The nuts 18 can be as in 2 represented by way of example, are stamped and bent nuts which have an anti-twist area 24 . In the example shown, the torsion-proof tion area 24 realized in particular by two opposing bends, which come when moving the nut receptacle 22 in its position of use with the contacting area 16 engaged. When it comes into engagement with the contacting area, the anti-rotation locking area 24 interacts with the contacting area 16 in such a way that the nut 18 is prevented from turning when the screw 20 is screwed in. In the example shown, this occurs in particular in that the anti-rotation area 24 surrounds the contacting area 16 in a U-shape.

In the 3 and 4 the structure and in particular the structure of the contacting area 16 can be seen more clearly due to the omission of parts of the contacting elements 12 shown.

As in the example shown, the contacting area 16 can be a flat metal part that has sections separated from one another by bends. The sections of the contacting region 16 extend away from the cell stack 10 with one of the extension directions of their areal extent in the direction Y perpendicular to the stacking direction X.

As in the example shown, the contacting area 16 can have a connecting section 26 . The connecting section 26 serves to connect the contacting region 16 to the connecting element 14. As in the example shown, the connecting section 26 can extend with one of the directions of its flat extent in the stacking direction X and with one of the directions of its flat extent in the direction Y perpendicular to the stacking direction X from the Cell stack 10 extend away.

The contacting region 16 can also have a bending section 28 which is connected to the connecting section 26 via a first bend and/or bend 30 . The bending area 28 extends, in particular as shown in the example shown, with its flat extension perpendicular to the stacking direction X.

The bending section 28 can be connected to a base section 34 via a second bend and/or bend 32 . The contacting region 16 is attached to the contacting element 12 with its base section 34, in particular as in the example shown. In the example shown, the second bend and/or bend 32 can be spaced apart from the first bend and/or bend 30 and oriented perpendicularly thereto. As in the example shown, a gap can be formed between the base section 34 and the bending section 28 , which gap extends from the second bend and/or bend 32 in the direction of the connecting section 26 .

The features of the invention disclosed in the present description, in the drawings and in the claims can be essential both individually and in any combination for the realization of the invention in its various embodiments. The invention can be varied within the scope of the claims and taking into account the knowledge of the person skilled in the art.

Reference List

10

cell stack

12

contacting elements

14

electrical connector

16

contacting areas

18

Mother

20

screw

22

mother recording

24

anti-rotation area

26

connection section

28

bending section

30

first turn/bend

32

second turn/bend

34

base section

X

stacking direction

Y

direction perpendicular to the stacking direction

Z

vertical direction

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

• US20200212404A1 [0004]
• JP2012243689A [0004]

Claims (10)

Accumulator, in particular for a motor vehicle, with a plurality of electrochemical cells for storing electrical energy, with a plurality of electrochemical cells being combined to form a cell stack (10) and being connected by means of a contacting element (16) to the cell stack (10 ) extends along, are electrically contacted, characterized in that at least two cell stacks (10) are arranged one behind the other in the stacking direction (X), wherein contacting elements (12) of both cell stacks (10) are electrically connected to one another by an electrical connecting element (14), wherein the connecting element (14) is electrically connected to at least one contacting region (16) of a contacting element (12). accumulator after claim 1 , characterized in that the connecting element (14) is connected to the contacting area (16), in particular by means of a screw (20) screwed into a nut (18), the axis of which, in particular, is at least substantially perpendicular to the stacking direction (X). is. accumulator after claim 2 , characterized in that the accumulator, in particular the contacting element (12), has a movable nut receptacle (22) in which the nut (18) can be received and moved into a position of use in which the screw (20) can be screwed into the Nut (18) for connecting the connecting element (14) with the contacting area (16) is possible. accumulator after claim 3 , characterized in that the nut receiver (22) is slidably attached to the contacting element (12) in the stacking direction in order to enable movement of the nut receiver (22) into the use position. accumulator after claim 3 or 4 , characterized in that the nut receptacle (22) is closed downwards, in particular in the form of a trough, in relation to the preferred orientation of the accumulator. Accumulator after one of claims 2 until 5 , characterized in that the nut (18) has an anti-rotation area (24) which interacts with the contacting area (16) in such a way that the nut (18) is prevented from turning when the screw (20) is screwed in, in particular the anti-rotation area ( 24) is designed in such a way that it comes into engagement with the contacting region (16) when the nut receptacle (22) with the nut (18) received therein is moved into its position of use. Accumulator according to one of the preceding claims, characterized in that the contacting area (16) is a flat metal part which has sections separated from one another by bends and/or angles (30, 32), sections of the contacting area (16) being connected to one of the Extension directions of their areal extent extend away from the cell stack (10) in the direction perpendicular to the stacking direction (Y). Accumulator according to one of the preceding claims, characterized in that the contacting area (16) has a connecting section (26) for connecting the contacting area (16) to the connecting element (14), the connecting section (26) extending with one of the directions of its areal extension extends away from the cell stack (10) in the stacking direction (X) and with one of the extension directions of its areal extent in the direction (Y) perpendicular to the stacking direction (X). accumulator after claim 8 , characterized in that the contacting region (16) has a bending section (28) which is connected to the connecting section (26) via a first bend and/or bend (30), the bending section (28) having one of the directions of extension of its flat extent in the vertical direction (Y) away from the cell stack (10) and is in particular oriented with its flat extent perpendicular to the stacking direction (X). accumulator, after claim 9 , characterized in that the bending section (28) is connected to a base section (34) via a second bend and/or bend (32), the contacting region (16) being attached to the base section (34) on the contacting element (12). , in particular wherein the second bend and/or bend (32) is oriented perpendicularly to the first bend and/or bend (30) and is spaced from it in such a way that a gap is formed between the base section (34) and the bend section (28), which extends away from the second bend and/or bend (32) in the direction of the connecting section (26).

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