Battery cell, system and method for manufacturing a battery cell composite, and battery cell composite

Abstract

A battery cell, a system comprising at least one such battery cell and a cell connector, a method for manufacturing a battery cell assembly using the system, and a corresponding battery cell assembly are provided. The battery cell (103) comprises a connection point (5) for electrically contacting the battery cell (103) by means of a cell connector (110), the surface of the connection point (5) facing away from the battery cell (103) having an inner section (5-I), an outer section (5-A), and a bending point (10) at which the inner section (5-I) is incorporated into the outer section (5-A), the outer section (5-A) of the surface is lowered relative to the bending point (10).

Description

Technical Field

[0001] A battery cell, a system having at least one such battery cell and a cell connector, a method for producing a battery cell assembly using the system, and a corresponding battery cell assembly are proposed. Background Art

[0002] The cell connectors (“busbars”) and the connection points (“terminals”) of the battery cells usually have a flat geometry in the contact area that is easy to produce. The cell connectors and the connection points can be connected, for example, by means of a joint that is achieved by laser welding.

[0003] In order to produce the smallest possible welding gap while taking into account geometrical tolerances in the contact region, the production of the cell composite generally requires high pressure contact forces against the connection points on the cell connectors.

[0004] Deviations in the geometry in the contact area can lead to (air) gaps between the surface of the connection point and the supporting surface of the cell connector, which can lead to air inclusions in the weld (pores, voids and / or defects), which reduce the strength and conductivity of the weld. In addition, due to the (air) gaps during welding, molten material can be ejected from the welding location and damage nearby components as "weld spatter".

[0005] Furthermore, the position of the smallest possible welding gap varies greatly around the possibly predetermined welding position. As a result, the first support point of the cell connector is usually produced at the edge or outer edge of the connection point, at which welding is undesirable due to the lack of sufficient material of the connection point. Depending on the shape tolerances of the geometry, one or more additional support points can be produced at any position in the contact area, which cannot be taken into account when predetermining the welding position. Summary of the invention

[0006] The object to be achieved is to provide a battery cell, a system having at least one such battery cell and a cell connector, and a method for producing a battery cell assembly using the system, with which a relatively small welding gap can be produced between the cell connector and the connection point with relatively low contact forces.

[0007] These objects are achieved by the subject matter of the independent patent claims. Advantageous embodiments, embodiments and improvements are the subject matter of the dependent patent claims.

[0008] According to a first aspect, a battery cell is provided, which comprises a connection point for electrical contacting of the battery cell by means of a cell connector.

[0009] Here and below, a battery cell is, for example, a secondary battery or an accumulator. A battery cell is thus, for example, a single rechargeable storage element for electrical energy. The battery cell can be, in particular, a round cell or a prismatic cell with a wound or folded core. The battery cell has a (central) longitudinal axis which extends transversely and which extends obliquely or perpendicularly to it and which extends between the top side and the bottom side of the battery cell.

[0010] The connection point forms one of the cell poles of the battery cell, for example, on the top or bottom side of the battery cell. The connection point is provided for connection to a cell connector by means of joining. A connection point is to be understood in particular as a component or a component group, or a region of a component or a component group, the surface of which faces away from the battery cell, when the battery cell is operated as intended, in direct contact with the cell connector.

[0011] The cell connector is, for example, a metal sheet, for example made of copper or aluminum. The cell connector is particularly provided for electrically contacting a plurality of battery cells and is correspondingly provided for connection by means of engagement with a plurality of connection points. For each connection point, the cell connector has a corresponding support surface.

[0012] In an advantageous embodiment of the first aspect, a surface of the connection point facing away from the battery cell has an inner section, an outer section and a kink at which the inner section merges into the outer section, wherein the outer section of the surface is stepped down relative to the kink.

[0013] The terms "inner" and "outer" are to be understood here relative to the lateral extension of the connection point, i.e. the inner section is closer to the center of the lateral extension of the connection point than the outer section or surrounds it. The surface of the connection point facing away from the battery cell can be understood as the surface of the connection point having a normal vector which contains a component parallel to the longitudinal axis and facing away from the interior of the cell.

[0014] For example, the connection point can have one outer section or a plurality of outer sections arranged spatially separated from one another. The one or more outer sections can spatially delimit one or more inner sections. The bending point forms the transition of the corresponding inner section to the corresponding outer section or the separation from the corresponding outer section.

[0015] Here and below, a bending point is understood to be a change in curvature introduced in a targeted manner in the surface of a connection point. For example, it is a transverse section of a connection point in which a flat inner section merges into an outer section extending obliquely or curved relative to it. The bending point forms a kind of edge or edge on which the supporting surface of the cell connector rests. The bending point serves in particular as a supporting point or supporting edge for the cell connector.

[0016] The descent of the outer section relative to the bending point means that the surface extends obliquely or curved relative to the longitudinal axis, so that the bending point forms the most exposed point or the most exposed edge of the connection point relative to the longitudinal axis. The "descent" is characterized in particular by the fact that the radius R2 of the circle inscribed in the concave internal geometry of the cell connector facing the connection point is greater than the radius R1 of the circle of the convex external geometry of the connection point, wherein the exposed point is located on the circle line and determines its radius R1, and the connection point does not touch the circle or protrude from the circle at any other position. Depending on the structural dimensions and implementation of the battery cell, the height offset from the outermost point of the inner section (=exposed point) to the outermost point of the outer section is, for example, 0.5 mm to 1 mm.

[0017] Such a connection point advantageously enables the manufacture of a battery cell complex with a relatively small welding gap at a predetermined position. Due to the bending point having a previously known position, the first geometric support point or the first geometric support edge is effectively displaced inwards based on the lateral extension of the connection point, at which first geometric support point or the first geometric support edge the material of the connection point is sufficient for the welding process. Statistically and procedurally, position tolerances from the cell connector to the connection point can be better compensated in manufacturing and the position of the minimum welding gap can be more reliably (pre-)determined, so that a higher strength and conductivity of the connection between the connection point and the cell connector can be achieved with similar pressing forces. Alternatively or additionally, taking into account the strength and conductivity to be achieved, it is conceivable to reduce the pressing force during the manufacturing process, so that, for example, material requirements and manufacturing tolerances regarding the pressing force can be reduced with similar strength and conductivity, and thus a cost-effective manufacture of the battery cell complex can be contributed.

[0018] In an advantageous embodiment according to the first aspect, the inner section of the surface is arranged in a plane. In other words, the inner section of the surface is designed to be flat. The plane extends obliquely to, in particular perpendicularly to, the longitudinal axis of the battery cell. In particular, the inner section of the surface together with the bending point forms the most exposed face of the connection point with respect to the longitudinal axis.

[0019] In an advantageous embodiment according to the first aspect, the surface of the connection point facing away from the battery cell has at least two bending points which laterally delimit the inner section of the surface. For example, the bending points are arranged on at least two side faces of the prismatic battery cell. This advantageously results in a second and possibly a third geometric support point or geometric support edge also at a predetermined, easily weldable position, in particular in an embodiment with symmetrical bending points.

[0020] In an advantageous design according to the first aspect, the bending point is in an inner section of the laterally surrounding surface. For example, the bending point is configured to extend in a circular shape in a plane.

[0021] In an advantageous embodiment of the first aspect, the one or more bending points are designed to extend in a plane. The plane extends obliquely to, in particular perpendicularly to, the longitudinal axis of the battery cell and forms the region of the connection point that is most exposed relative to the longitudinal axis. The one or more bending points can be designed to extend in a straight line or in a curve in the plane, for example.

[0022] In an advantageous design according to the first aspect, the outer section of the surface is designed to descend linearly or curvedly relative to the bending point. The linear descent is to be understood in particular as an oblique extension of the surface relative to the longitudinal axis, by which a "sharp" edge is formed at the bending point according to the angle with the longitudinal axis, whereby the support point or the supporting edge of the cell connector can be predetermined particularly accurately. The outer section can be designed in this case in the form of the circumferential surface of a truncated cone or in the form of the circumferential surface of a truncated pyramid. The curved descent is to be understood in particular as a curved extension of the surface (protrusion), by which a "soft" edge is formed at the bending point according to the radius of curvature, whereby the supporting surface of the cell connector can be pressed particularly without gaps. The outer section can be designed in this case in the form of the circumferential surface of a spherical layer.

[0023] In an advantageous design according to the first aspect, the battery cell further comprises a through contact portion, which extends centrally through the connection point into the interior of the battery cell, wherein the side of the through contact portion facing away from the battery cell does not protrude beyond the surface of the battery cell facing away from the connection point at the bending point. The through contact portion is to be understood as a connector between a conductor sheet inside the cell and the connection point for electrically contacting the electrode layer of the battery cell. The through contact portion may also be referred to as a rivet. The surface of the through contact portion is in particular configured to be flat. For example, the surface of the through contact portion and the inner section of the surface of the connection point may be arranged in one plane. Alternatively, the surface of the through contact portion is lowered relative to the inner section of the surface of the connection point with respect to the longitudinal axis, thereby ensuring that one or more support points or support edges for the cell connector are formed by one or more bending points.

[0024] In an advantageous embodiment according to the first aspect, the connection point has a lateral extension of a predetermined width B, and the outer section of the surface has a lateral extension between B / 16 and B / 4, in particular between B / 8. This advantageously results in one or more bearing points or one or more bearing edges being effectively displaced inwards with respect to the lateral extension of the connection point and ensures that the material of the connection point is sufficient for the welding process regardless of the absolute dimensions of the elements to be connected and the weld seam. Advantageously, when a through-contact is present, one or more bearing points or one or more bearing edges are spaced apart from the through-contact with respect to the lateral extension of the connection point, so that the through-contact does not participate in the welding process. Depending on the battery size, the distance from the through-contact and from the edge of the connection point can be, for example, approximately 2 to 3 mm.

[0025] According to a second aspect, a system is provided, comprising at least one battery cell according to the first aspect and a cell connector. For each battery cell, the cell connector has a bearing surface for electrically contacting the corresponding battery cell. The corresponding bearing surface of the cell connector has a predetermined deformation that deviates from the plane.

[0026] Such a system advantageously enables the production of battery cell complexes with relatively small welding gaps at predetermined locations. Due to the bending point with a previously known position in combination with the predetermined deformed bearing surface of the cell connector, one or more bearing points or one or more bearing edges can be reliably displaced inwardly with respect to the lateral extension of the connection point, with the advantages described above. However, the above statements about the first aspect also apply to the second aspect and vice versa. The deformation can in particular be a curvature or camber, which is introduced, for example, by bulging.

[0027] In an advantageous embodiment of the second aspect, the corresponding contact surface of the cell connector is concave.

[0028] In an advantageous design according to the second aspect, the corresponding supporting surface of the cell connector is formed complementarily to the surface of the connection point of the corresponding battery cell. Here and hereinafter, complementary means that the supporting surface has an inner area corresponding to the inner section of the surface of the connection point and an outer area corresponding to the outer section of the surface of the connection point, wherein at least the outer area has a shape adapted to the shape of the surface of the outer section of the surface of the connection point. For example, both the outer section of the surface of the connection point and the outer area of ​​the supporting surface of the cell connector can be configured to be curved. The radius of curvature of the outer section of the surface of the connection point is always smaller than the radius of curvature of the outer area of ​​the supporting surface of the cell connector, thereby ensuring that one or more bending points always form one or more supporting points or one or more supporting edges for the cell connector.

[0029] In an advantageous design according to the second aspect, the curvature of the outer section of the corresponding surface of the connection point facing away from the battery cell is configured to be greater than the curvature of the corresponding support surface of the cell connector. In other words, the radius of curvature of the outer section of the surface of the connection point is smaller than the radius of curvature of the outer area of ​​the support surface of the cell connector.

[0030] According to a third aspect, a method for producing a battery cell complex by using the system according to the second aspect is provided. The method comprises the following steps, in particular in the order given:

[0031] - providing and arranging at least one battery cell such that the connection point forms the top side of the respective battery cell;

[0032] - providing and arranging a cell connector above the respective battery cell such that the respective support surface of the cell connector covers an inner section of a connection point of the respective battery cell so that the cell connector rests on a bending point of the respective battery cell;

[0033] - applying a force to the abutting cell connector so that the cell connector is pressed against the top side; and

[0034] - Connect the cell connectors at the bending points of the respective battery cells in a materially bonded manner to the connection points.

[0035] However, the above statements about the second aspect also apply to the third aspect and vice versa. The battery cells are arranged such that their longitudinal axes extend in parallel. It is conceivable here to provide a plurality of battery cells in one step and to place a cell connector against it in a subsequent step and then connect it to the battery cells. Alternatively or additionally, it is also conceivable to respectively provide a part of the battery cells provided for connection, for example only a single battery cell, and to respectively connect them one after the other to the cell connector.

[0036] The force is applied in particular parallel to the longitudinal axis of the battery cell, for example centrally for each battery cell.

[0037] In an advantageous embodiment of the third aspect, the cell connector is connected to the connection point in the region of the bending point by means of a laser welding process.

[0038] According to a fourth aspect, a battery cell complex is provided. The battery cell complex is produced according to the method according to the third aspect. However, the above statements about the third aspect also apply to the fourth aspect. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Embodiments of the present invention are explained in more detail below with reference to the schematic drawings. In the drawings:

[0040] Figure 1shows a detail of the schematic structure of a prismatic battery cell in the region of the cell poles;

[0041] Figure 2 It shows that there are two Figure 1 A prismatic battery cell and a cell connector system;

[0042] Figure 3 It is shown that in Figure 1 A prismatic battery cell is connected to (from left to right) a flat cell connector; a concavely curved cell connector; an irregularly curved cell connector; and a support point when connected to a convexly curved cell connector;

[0043] Figure 4 shows a detail of the schematic structure of a round battery cell in the region of the cell poles;

[0044] Figure 5 and Figure 6 A system including a battery cell having a bend point at a connection point and a curved cell connector is shown. Figure 5 ) and the detailed view ( Figure 6 );

[0045] Figure 7 Figure 2 shows the support angle between the cell connector and the battery cell (from left to right); and the support angle and position with position tolerance according to Figure 5 systems; and

[0046] Figure 8 Shown by using Figure 5 Flow chart of a system for manufacturing battery cell complexes. DETAILED DESCRIPTION

[0047] Elements of the same design or function are marked with the same reference symbols in all the figures.

[0048] Figure 1 An exemplary section of a prismatic battery cell 101 is shown. The battery cell 101 has a positive electrode and a negative electrode, each of which is formed from a plurality of electrode layers 1, which are arranged in a housing 2 of the battery cell 101, the housing 2 having a central longitudinal axis L and a transverse extension perpendicular to the longitudinal axis L. A cover 3 ("cover plate") is arranged on the top side of the housing 2 and is connected to the housing 2 by means of an ultrasonic or laser welding process. The corresponding weld points are indicated with the reference numeral 4.

[0049] The battery cell 101 also has a flat connection point 5 for electrically contacting the battery cell 101, which serves as a cell pole. The connection point 5 is arranged on the side of the cover 3 facing away from the housing interior and is electrically isolated from the housing 2 by an insulation 6 arranged between the cover 3 and the connection point 5.

[0050] A punch-shaped through-contact 5a extends through the connection point 5 into the interior of the housing and electrically connects the connection point 5 to the electrode layer 1 via one or more conductor plates 7 of the electrode layer 1. An electrically insulating seal 6a is also arranged between the through-contact 5a and the cover 3. The through-contact 5a is connected to the connection point 5 by means of an ultrasonic or laser welding process. The corresponding welding point is indicated by the reference numeral 8.

[0051] based on Figure 2 It shows that there are two Figure 1 1 and 10. An exemplary system 100 of prismatic battery cells 101a, 101b and a cell connector 110 having bearing surfaces 111a, 111b. The battery cells 101a, 101b have an offset d1 parallel to the longitudinal axis.

[0052] The connection points 5 are each designed in the form of a cuboid, on the top side of which a substantially flat contact surface is formed under shape tolerances. However, the cell connector is also designed to be flat under shape tolerances.

[0053] When forming the battery cell complex, the system 100 is loaded with a force F (bold arrow), and the cell connector 110 is pressed against the corresponding connection point 5 and / or the through-contact 5a and then welded to the corresponding connection point 5 (dashed arrow). For this purpose, the position of the weld seam S can be predetermined, wherein the corresponding support points A1, A2 (see Figure 3 ) or the position of the corresponding minimum possible welding gap varies significantly depending on the tolerance and / or shape of the battery cell connector 110, as shown below with reference to Figure 3 Explained in more detail.

[0054] Figure 3 It shows that in Figure 1 Exemplary support points A1 , A2 when connecting a prismatic battery cell to different cell connectors 110 a - 110 d , wherein for better illustration each cell connector 110 a - 110 d is shown only in the region of the battery cell 101 .

[0055] The cell connector 110a (first from the left) has a flat bearing surface, but is arranged skewly on the flat surface of the corresponding connection point, for example due to manufacturing tolerances. A first bearing point A1 (indicated by a dashed line) with the smallest possible welding gap is produced at the edge of the connection point. At the edge of the connection point, only little material is available for the welding process, so that the welded connection at this location may have potentially insufficient strength and / or conductivity.

[0056] The cell connector 110b (second from the left) has a concavely curved support surface. A first support point A1 with the smallest possible welding gap is also produced at the edge of the connection point. For example, a second support point A2 (also indicated by a dashed line) is additionally produced at the opposite second edge of the connection point. This leads to the same problems as in the cell connector 110a.

[0057] The cell connector 110c (3rd from the left) has an irregularly curved support surface. A first support point A1 with the smallest possible welding gap is also produced at the edge of the connection point. For example, a second support point A2 is additionally produced at a position of the connection point that is indented relative to the opposite second edge. With respect to the first support point A1, the same problems arise as in the cell connectors 110a and 110b. In principle, the welding process can be carried out at the second support point A2, but due to shape tolerances, the second support point A2 is in an uncertain, relatively arbitrary position.

[0058] The cell connector 110d (4th from the left) has a convexly curved support surface. A first support point A1 with the smallest possible welding gap is produced at a position that is set back relative to the edge of the connection point. Similar to the cell connector 110c, in principle, the welding process can be carried out at the first support point A1, but due to shape tolerances, the first support point A1 is in an uncertain, relatively arbitrary position.

[0059] However, it should also be noted that the above-described behavior for mechanically determined displacements in three dimensions also generally leads to a third support point (not shown). This third support point is produced similarly to the above statements, with the same disadvantages.

[0060] based on Figure 4 An exemplary section of a CT image of a cylindrical battery cell 102 ("round cell") is shown. The battery cell 102 has a positive electrode and a negative electrode, each of which is formed by a plurality of electrode layers 1, for example wound, which are arranged in a housing 2 of the battery cell 101. The housing 2 has a central longitudinal axis L and a transverse extension perpendicular to the longitudinal axis L. The cover 3 is arranged on the top side of the housing 2 and is connected to the housing 2 by means of an ultrasonic or laser welding process. The corresponding welding points are indicated with the reference numeral 4.

[0061] The battery cell 102 also has a flat connection point 5 for electrically contacting the battery cell 102, which serves as a cell pole and is usually designed in a disk-shaped manner. The connection point 5 is formed, for example, centrally from the material of the cover 3 and is electrically separated from the housing 2 by an electrically insulating seal 6a arranged between the cover 3 and the housing 2.

[0062] Under the cover 3 there is arranged a current collector 5 b (“current collector”) which connects the connection point 5 via the disk 9 and one or more conductor plates 7 ( Figure 4 The disc 9 can be an anode disc or a cathode disc, which is connected to the anode or cathode of the electrode layer 1 via one or more conductor sheets 7, respectively. The other, cathode or anode disc, is arranged, for example, on the bottom side (not shown in detail) of the battery cell 102. The current collector 5b is connected to the cover 3 by means of an ultrasonic or laser welding process. The corresponding welding points are indicated by the reference numeral 8.

[0063] Corresponds to Figure 3 The support points A1 , A2 shown in the cuboid-shaped connection point 5 give rise to similar problems with respect to the strength or conductivity and reproducibility of the weld point as with the disk-shaped connection point 5 of a round cell.

[0064] As reference Figure 5 As shown, a battery cell 103 with a curved or bent surface of the connection point 5 is proposed below. As shown in the figure, the battery cell 103 is, for example, a prismatic battery cell, which has a rectangular, for example square, laterally extending connection point 5, similar to the Figure 1 or the battery cell is a cylindrical battery cell having a circular, laterally extending connection point 5, similar to that according to Figure 4 The battery cell 102 of FIG. 1 is different from the battery cell 103 in that only the inner section 5-I of the surface of the connection point 5 facing away from the battery cell 103 is designed to be flat relative to the central longitudinal axis L, while one or more outer sections 5-A relative to the central longitudinal axis L are lowered relative to the plane, so that a bending point 10 is formed at the transition from the outer section to the inner section. This obvious edge can help to reproducibly produce a minimum welding gap at a fixed position, as explained in more detail below: Therefore, the first geometric support point A1 can be shifted inwardly toward the central longitudinal axis L to the position of the bending point 10, thereby ensuring that the material of the connection point 5 is sufficient for the welding process at this point. If the bending point 10 is implemented symmetrically, a second / third support point A2 is also generated at a defined and weldable point. The descending surface in the outer section 5-A can extend in a straight line or in a curved manner. In particular, it can be provided that the support surface of the cell connector 110 is complementary to the descending surface in the outer section 5-A, for example, curved.

[0065] As based on Figure 6It can be seen from the enlarged part X in that the curvature of the descending surface in this outer section 5-A is always implemented to be greater than the curvature of the cell connector 110, that is, the corresponding radius of curvature R1 of the descending surface in the outer section 5-A is always selected to be smaller than the radius of curvature R2 of the support surface, thereby ensuring that the minimum gap geometry is always generated at the bending point 10. In the case of symmetrical implementation, it can also be ensured in three dimensions that the third support point is arranged along the corresponding bending point and an overall relatively small gap is generated. Therefore, it can be advantageously contributed to statistically and procedurally safer or better weldable positioning of the smallest possible welding gap, and thus contribute to higher strength and conductivity of the connection.

[0066] As based on Figure 7 As shown, the position tolerance and manufacturing tolerance between the cell connector 110 and the connection point 5 can be better compensated. Even when the cell connector 110b is applied tilted (left) or offset (offset d, right), the support points A1 and A2 are formed at predetermined retracted positions with the above advantages.

[0067] exist Figure 8 The flowchart in shows the method steps for producing a cell composite using a plurality of the proposed battery cells 103 and the convexly curved cell connectors 110 b.

[0068] First ( S11 , left), the battery cells 103 are provided and arranged such that the connection points 5 to be connected are oriented parallel to one another.

[0069] Then ( S12 , left) the cell connector 110 b is placed onto the connection point 5 , so that the cell connector 110 b abuts against the bending point 10 of the battery cell 103 .

[0070] Thereafter ( S13 , left), the cell connector 110 b is pressed against the connection point 5 , and is welded to the connection point 5 at a predetermined position corresponding to the bending point 10 of the battery cell 103 ( S14 , left).

[0071] Alternatively, in step S11 only a portion of the battery cells 103 to be connected are provided ( S21 , right), and steps S11 to S14 are iteratively executed for each portion of the battery cells 103 to be connected ( S21 to S24 , right).

[0072] Reference numerals list

[0073] 1 Electrode layer

[0074] 2 Shell

[0075] 3 Cover

[0076] 4 welding points

[0077] 5 Connection points

[0078] 5a Through contact

[0079] 5b Current Collector

[0080] 6 Insulation

[0081] 6a Seals

[0082] 7 Conductor sheet

[0083] 8. Welding Seams

[0084] 9 plates

[0085] 10 bending points

[0086] 100 systems

[0087] 101-103, 101a, 101b battery cells

[0088] 110, 110a-d battery connector

[0089] F-Force

[0090] L longitudinal axis

[0091] S weld

[0092] A1, A2 support points

[0093] Section 5-A, 5-I

[0094] R1, R2 radius of curvature

[0095] X-enlarged section

[0096] dOffset

[0097] S11-S24 Method Steps

Claims

1. A battery cell (103) comprising a connection point (5) for electrically contacting the battery cell (103) by means of a cell connector (110), wherein: - The surface of the connection point (5) facing away from the battery cell (103) has an inner section (5-I), an outer section (5-A) and a bending point (10), at which the inner section (5-I) merges into the outer section (5-A), wherein the outer section (5-A) of the surface descends relative to the bending point (10).

2. The battery cell (103) according to claim 1, wherein: The inner section (5-I) of the surface is arranged in a plane.

3. The battery cell (103) according to claim 1 or 2, wherein: The surface of the connection point (5) facing away from the battery cell (103) has at least two bending points (10), which delimit an inner section (5-I) of the surface in the transverse direction.

4. The battery cell (103) according to claim 1 or 2, wherein: The bending point (10) surrounds the inner section (5-I) of the surface in the lateral direction.

5. The battery cell (103) according to one of the preceding claims, wherein: The bending point (10) or the plurality of bending points are designed to extend in a plane.

6. The battery cell (103) according to one of the preceding claims, wherein: The outer section (5-A) of the surface is designed to descend linearly or in a curved manner relative to the bending point (10).

7. The battery cell (103) according to one of the preceding claims, further comprising a through-contact (5a) which extends centrally through the connection point (5) into the interior of the battery cell (103), wherein: The side of the through-contact (5a) facing away from the battery cell (103) does not protrude beyond the surface of the connection point (5) facing away from the battery cell (103) at the bending point (10).

8. The battery cell (103) according to one of the preceding claims, wherein: The connection point (5) has a lateral extension of a predetermined width B, and the outer section (5-A) of the surface has a lateral extension between B / 16 and B / 4, in particular B / 8.

9. A system (100) comprising at least one battery cell (103) and a cell connector (110b) according to one of the preceding claims, wherein: The cell connector (110b) of each battery cell (103) has a supporting surface for electrically contacting the corresponding battery cell (103), and the corresponding supporting surface of the cell connector (110b) has a predetermined deformation that deviates from the plane.

10. The system (100) according to claim 9, wherein: The corresponding support surface of the cell connector (110b) is designed to be concave.

11. The system (100) according to claim 9 or 10, wherein: The corresponding contact surface of the cell connector (110b) is formed complementary to the surface of the connection point (5) of the corresponding battery cell (103).

12. The system (100) according to claim 9 or 10, wherein: The curvature of an outer section (5-A) of the connection point (5) facing away from the corresponding surface of the battery cell (103) is greater than the curvature of the corresponding support surface of the cell connector (110b).

13. A method for producing a battery cell assembly using a system (100) according to any one of claims 9 to 12, comprising the following steps: - providing and arranging the at least one battery cell (103) such that the respective connection point (5) forms the top side of the respective battery cell (103); - providing and arranging a cell connector (110) above the corresponding battery cell (103) so that the corresponding supporting surface of the cell connector (110b) covers the inner section (5-I) of the connection point (5) of the corresponding battery cell (103), so that the cell connector (110b) rests on the bending point (10) of the corresponding battery cell (103); - applying a force (F) to the resting cell connector (110b) so that the cell connector (110b) is pressed against the top side; and - Connecting the cell connector (110b) to the connection point (5) at the bending point (10) of the respective battery cell (103) in a materially bonded manner.

14. The method according to claim 13, wherein: The cell connector (110b) is connected to the connection point (5) in the region of the bending point (10) by means of a laser welding process.

15. A battery cell composite produced by the method according to claim 13 or 14.

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