Method for producing a recess on a battery housing

Abstract

The invention relates to a method for producing a recess (25) in an outer layer (20), in particular an insulation layer (22) of the outer layer (20), of a battery cell (100), in particular for a battery system of a vehicle, said method comprising: - providing (110) a battery cell (100) having o a battery body (10) for storing energy and o an outer layer (20) surrounding the battery body (10), - defining (120) a contour (K) of a recess (25) in the outer layer (20) by traversing and irradiating the outer layer (20) by means of a laser, - heating (130) the outer layer (20) by traversing and irradiating by means of the laser in a region (B) defined by the contour (K), and - at least partially detaching (140) the outer layer (20) in the region (B) defined by the contour (K) in order to produce the recess (25) in the outer layer (20). The invention further relates to a battery cell (100) and to a battery system.

Description

[0001] Description

[0002] METHOD FOR MAKING A CUTOUT IN A BATTERY HOUSING

[0003] The invention relates to a method with the features of the independent method claim, a battery cell with the features of the independent patent claim relating to a battery cell, and a battery system with the features of the independent patent claim relating to a battery system.

[0004] Battery cells for providing electrical energy are known. These can be connected to form a battery system, for example, to be used as an energy source in an (electric) vehicle. It may be possible to connect at least two battery cells together. For example, these can be mechanically connected, in particular by bonding. Alternative battery cells or systems are disclosed, for example, in US 2024 / 0014479 A1, CN 219203451, or US 2022 / 0045406 A1.

[0005] The current state of the art has some drawbacks. For example, connecting adjacent battery cells can be difficult, particularly positioning them relative to each other. The robustness, stability, and / or durability of the connection may also be in need of improvement. This can reduce safety, for instance, in the event of external force (such as a vehicle accident involving a battery cell). Specifically, there may not be an optimized adhesive force between adjacent battery cells, especially for fastening, such as gluing. Furthermore, known manufacturing processes may not be sufficiently flexible and / or adaptable, which can increase costs, particularly in production.

[0006] It is therefore an object of the present invention to overcome at least one of the disadvantages described above, at least partially. In particular, it is an object of the invention to provide an improved method, an improved battery cell, and / or an improved battery system. This may include improving assembly, robustness, stability, durability, safety, flexibility, and / or adaptability.

[0007] The foregoing problem is solved by a method with the features of the independent method claim, a battery cell with the features of the independent claim relating to a battery cell, and a battery system with the features of the independent claim relating to a battery system. Further features and details of the invention will become apparent from the dependent claims, the description, and the drawings. Features and details described in connection with the method according to the invention naturally also apply in connection with the battery cell and / or the battery system according to the invention, and vice versa, so that the disclosure of the individual aspects of the invention always makes, or can make, reciprocal references.In particular, advantages described within the first, second and / or third aspect also apply to the first, second and / or third aspect.

[0008] The above problem is solved according to a first aspect by a (manufacturing and / or manufacturing) method for producing a recess in an outer layer, in particular an (electrical) insulating layer of the outer layer, of a battery cell (e.g. according to the second aspect), in particular for a battery system (e.g. according to the third aspect) of a vehicle, comprising the method:

[0009] Providing a battery cell comprising: o an (internal) battery body for (electrical and / or chemical) energy storage or energy provision and o an outer layer (e.g., lying above) and / or enclosing the battery body (fully),

[0010] Defining the contour of a recess in the outer layer by tracing and irradiating the outer layer with a laser,

[0011] Heating the outer layer by scanning and irradiating it with a laser, in an area defined by the contour, and

[0012] - at least partial (area-wide) detachment of the outer layer in the area defined by the contour in order to create the recess in the outer layer.

[0013] The recess can be designed as a depression, particularly in the battery cell material, especially the outer layer, preferably the insulating layer. The recess can have a cylindrical or cuboid (basic) shape. It is also possible for the edges of the recess to be chamfered and / or rounded. This can improve assembly, especially positioning during tying (see below), and / or the adhesive force.

[0014] The battery cell can be configured to provide electrical energy. The battery cell can preferably have at least one, and in particular two, electrical contacts configured to draw electrical energy from the battery body from outside the battery cell. For example, an electrical voltage and / or current can be drawn (via the electrical contacts).

[0015] Defining the contour of a recess in the outer layer by tracing and irradiating the outer layer with a laser can result in a closed contour, for example, a rectangle (for a cuboid recess) or a circle (for a cylindrical recess). For instance, the recess contour can be defined on an outward-facing surface of the battery cell, particularly the outer layer, such as the insulating layer. This definition process can involve creating and / or burning in the contour. The laser can essentially trace the contour above the outer layer while simultaneously irradiating the outer layer. This allows the outer layer to be defined along the contour, in particular (at least partially) burned in and / or dissolved and / or liquefied. Preferably, the outer layer can be removed down to and / or excluding the casing(s).

[0016] Heating the outer layer by scanning and irradiating it with a laser within a contour-defined area can be performed depending on at least one laser parameter, in particular the laser power, laser wavelength, and / or pulse repetition rate. By heating, especially by (continuous) scanning and irradiation, the area defined by the contour (especially the area enclosed by the contour) can be processed. In the simplest case, the contour can be a closed rectangle. The area can then be the (rectangular) surface enclosed by the contour. Preferably, the outer layer, especially the insulating layer, is heated within a contour-defined area. It can be provided that the heating process causes the outer layer (at least partially), especially the insulating layer, and particularly preferably the adhesive of the insulating layer, to dissolve, liquefy, and / or burn away.Accordingly, the heating process, in particular the duration and / or intensity of the irradiation, can be specific to the thickness and / or material of the outer layer, especially the insulating layer, preferably the adhesive. Preferably, at least one laser parameter can be set and / or configured to heat (only) the adhesive. It can be provided that the outer layer, especially the insulating layer and / or the adhesive, detaches (at least) partially as a result of the heating.

[0017] The partial removal of the outer layer in the area defined by the contour, in order to create the recess in the outer layer, can be achieved mechanically (see below). It may be sufficient to position and / or rotate the battery cell with the defined area facing downwards. This allows gravity to initiate and / or assist the removal. Additionally or alternatively, mechanical peeling can be performed, for example (manually) with pliers / tweezers and / or (automatically) with a gripper. In other words, the outer layer, particularly the insulating layer, can be (at least partially) removed (completely). This creates the recess. In other words, the recess can form a depression in the surrounding (unremoved) outer layer and / or insulating layer.Preferably, the housing remains unchanged and / or undeformed, particularly apart from any slight [reversible] heating. The (at least partial) removal can then be made possible (only) by defining and / or heating. Defining the recess creates an edge region, enabling robust and / or reliable removal along this edge. Heating preferably dissolves the adhesive in the insulating layer. This can enable faster, higher-quality, and / or more flexible manufacturing. Furthermore, the process and / or a single production line can be used to process different battery cells (of varying sizes and / or geometries). This can offer a particular advantage in terms of flexibility, especially when using a laser.The laser can be controlled, for example, by a control unit via a data connection. This control unit can contain geometric information about the battery cell, outer layer, insulating layer, adhesive, and / or corresponding materials and / or thicknesses. This enables precise manufacturing. The recess, particularly its base, can be designed to have a residual and / or specific surface structure created by heating. Accordingly, the recess, especially its base, can be configured to provide improved bonding to an adjacent battery cell. This can enhance manufacturing and / or assembly.

[0018] Within the scope of the invention, it may be advantageous that the provision includes manufacturing the battery cell, comprising:

[0019] Manufacturing the battery body for energy storage and

[0020] Manufacturing the outer layer (surrounding the battery body), comprising an (inner) housing and an insulating layer, on an outward-facing surface of the battery body, comprising: o arranging the housing on the battery body, whereby the housing completely surrounds the battery body, o arranging a support substrate, in particular a support substrate film, (outside) on the housing, and o applying an adhesive to the support substrate to obtain the insulating layer, comprising the support substrate and the adhesive. The outer layer can be arranged on, outside, on an external, and / or outward-facing surface of the battery cell. The insulating layer can be configured as two layers. A first (inner) layer can have a housing. This housing can be designed to protect the battery body and / or prevent the leakage of parts of the battery body.A second (outer) layer can include an insulating layer. This can be achieved by applying a carrier substrate, such as an (electrically) insulating plastic mesh, to the housing. Furthermore, an (insulating) adhesive can be applied (before and / or after) the carrier substrate and / or the housing. The carrier substrate and the adhesive can bond together to form the insulating layer. The insulating layer can provide thermal and / or electrical insulation for the housing and / or the battery body.

[0021] Within the scope of the invention, it is conceivable that, when defining the contour, it has a self-contained shape on an outwardly facing surface of the outer layer, wherein the shape of the contour is specific for the recess.

[0022] The contour can have a closed and / or two-dimensional shape. Preferably, the contour can have a simple geometric shape, such as a rectangle and / or a circle. This can improve manufacturing speed (in particular, the process can be carried out quickly). It is also possible to choose a more complex geometric shape. For example, a polygon and / or a star shape can be used. This can improve the positive fit between the (subsequently created) recess and an adjacent battery cell, especially for a bonding adhesive used for bonding. It is also possible that the shape of the contour and / or recess improves reliability and / or safety during manufacturing. For example, different battery cells, e.g.,Designed for different applications, voltages, currents and / or quality levels, each with its own contour and / or recess shape. This helps prevent and / or more easily detect connection errors.

[0023] Within the scope of the invention, it can be provided that during the defining process the contour is burned into the outer layer, whereby the outer layer is at least partially removed, in particular the insulating layer being completely removed and the housing not being removed. It is further conceivable that, particularly before defining and / or heating, the outer layer, especially the insulating layer, for example the carrier substrate and / or the adhesive, is pretreated with a solvent which is designed to facilitate the defining and / or heating process.

[0024] The solvent can be configured to specifically pretreat the adhesive and / or the substrate, in particular to dissolve, loosen, heat, chemically dissolve, and / or warm (e.g., through an exothermic reaction). This can accelerate and / or facilitate at least partial removal.

[0025] It is also conceivable that the heating of the outer layer by scanning and irradiation encompasses an area of ​​the outer layer framed by the contour, wherein in particular the insulating layer, preferably the adhesive in the insulating layer, is at least partially dissolved by the laser, wherein in particular the adhesive is heated so strongly that it dissolves (in particular at least partially liquefies) and / or is burned.

[0026] Accordingly, it can be provided that only the adhesive is processed, dissolved, and / or burned by the laser. At least one laser parameter, in particular the wavelength, can be specifically adjusted to dissolve (only) the adhesive. For example, a wavelength of 1 fm to 10 m, particularly from 10 pm to 10 mm, for example from 10 nm to 1 mm, preferably from 100 nm to 100 pm, particularly preferably from 1 pm to 25 pm, ideally from 5 pm to 15 pm, can be used. The adhesive can, for example, be an epoxy resin. This can exhibit very high robustness. It can also be provided that the adhesive is a UV adhesive, which can be cured and / or dissolved, in particular, by UV light. During this process, the adhesive (together with the substrate) can be removed.

[0027] Within the scope of the invention, it is optionally possible that the at least partial removal includes a mechanical peeling off of at least an outwardly facing part of the outer layer, in particular the insulating layer, in the area defined by the contour.

[0028] Furthermore, the invention may provide that the recess is created by at least partial detachment, wherein an outwardly (away from the battery body) facing base of the recess is designed for attachment, in particular fastening and / or gluing, to an adjacent battery cell, wherein the base, in particular the remaining insulating layer and / or the support substrate, has a surface structure, preferably with increased surface roughness, which provides increased adhesive force during attachment. The (mechanical) attachment may include arranging (to one another), preferably (irreversibly) fastening, in particular gluing, e.g., with an adhesive. The adjacent (initially separated) battery cell, in particular comprising a bulge complementary to the recess, may be positioned on the battery cell, in particular on and / or in the recess.Before, after, and / or during this process, bonding, in particular the fastening and / or application of a bonding adhesive (in between), can be carried out. This bonding can create a rigid support structure and / or a battery system comprising at least two battery cells. The recess, particularly its base, can preferably have a surface texture. This texture can be formed on the housing. It can be provided that a material of the housing is roughened (on the surface), particularly by the laser. Alternatively or additionally (and particularly preferably), it can be provided that the insulating layer, in particular the support substrate and / or the adhesive, remains at least partially behind (upon removal), and preferably (as a result) the residues have a (rough) surface texture. The base can be designed for increased surface roughness.This can be achieved, for example, using a laser, particularly through the heating method (see below). It may be possible to detect and / or verify the surface structure, especially the surface roughness, by measuring the corresponding rz values, e.g., with a profilometer. Alternatively or additionally, an optical measurement method may be used, such as laser triangulation, focal microscopy, and / or atomic force microscopy (AFM). The surface structure may exhibit a (repeating) pattern and / or geometric shapes. This can improve the manufacturing speed. The surface structure may be terraced, at least in sections, and may include distinct plateaus. The surface structure may also feature (regular) peaks and / or valleys (in the base) of the recess.These can be manufactured relatively easily and / or quickly. Alternatively or additionally, circles, spiral shapes, and / or polygons, especially hexagons, can be formed. This can (further) improve the adhesive force. The surface structure can provide improved bonding, particularly with enhanced adhesive force. Alternatively or additionally, a (rough) surface structure can be applied to the base and / or the housing, for example, by gluing it on. This can be achieved, for example, with a (rough) grid, such as one made of plastic.

[0029] With regard to the present invention, it is conceivable that when heating the outer layer by scanning and irradiating it with the laser, the scanning and irradiation is carried out depending on a (geometric and / or angled) irradiation pattern, wherein the irradiation pattern is configured to heat the outer layer, in particular the insulating layer, preferably the adhesive, in such a way that a (geometric) heating structure is formed therein, which is in particular specifically, preferably complementarily, designed to the surface structure that remains at the bottom of the recess after at least partial removal.

[0030] The laser and / or the method can be configured to align the laser (laser beam) at different positions and / or angles during scanning and / or irradiation. Alternatively or additionally, at least one laser parameter, in particular the power, wavelength, and / or pulse rate, can be varied. This allows the heating structure to be specifically formed. A specific, predefined area (the heating structure) can form in the outer layer. Upon subsequent at least partial detachment, the surface structure (in and / or encompassing [at least partially] the [remaining] insulating layer, in particular in the adhesive and / or the substrate and / or the bond encompassing both) can be formed. The surface structure can preferably be complementary to the heating structure.

[0031] Furthermore, it is conceivable that the heating structure and / or surface structure has a varying thickness at least in sections, preferably through a multitude of depressions (valleys) and / or elevations (mountains).

[0032] The depressions and / or elevations can be configured as grooves and / or bulges. They can be configured relative to an (outwardly facing) surface of the battery body, housing, insulating layer, substrate, and / or adhesive, with the varying thickness, and preferably the depressions and elevations, being configured at least partially (essentially) perpendicular to the surface.

[0033] Within the scope of the invention, it may be advantageous that the defining and / or heating, in particular the irradiation pattern, has a preferred direction, whereby the recess and / or the base, and in particular the surface structure, provides an improved area moment of inertia, especially for attachment to an adjacent battery cell.

[0034] For example, the contour and / or area can be elongated, rectangular, or strip-shaped, e.g., along a vertical axis, with the resulting recess also being arranged essentially along the vertical axis. This allows for optimization of the adhesive force and / or the area moment of inertia during and / or through the bonding process. This can improve robustness and / or strength. It also allows for a (comparatively) reduced number and / or area of ​​the recess, which can minimize manufacturing time. Alternatively or additionally, a preferred direction along the horizontal and / or transverse direction can (of course) be provided (which are perpendicular to each other and / or to the vertical). This can enable a (further) improved connection.Depending on the (final) geometry and / or design of the battery system, this also allows for an arrangement and / or extent of the recesses and / or connections that (overall) enables optimized (mechanical) robustness and / or (therefore) safety. This allows the battery cells and / or the battery system to exhibit particularly good robustness against external forces.

[0035] The above problem is further solved by a battery cell according to the invention, comprising a battery body for energy storage and an outer layer surrounding the battery body, wherein the outer layer has at least one recess which was produced by the method according to the first aspect.

[0036] This results in the same advantages with regard to a battery cell according to the invention as have already been described with regard to a method according to the invention.

[0037] The above problem is further solved by a battery system according to the invention, in particular for a vehicle, comprising at least one battery cell according to the second aspect.

[0038] This results in the same advantages with regard to a battery system according to the invention as have already been described with regard to a method and / or a battery cell according to the invention.

[0039] A battery system may also be provided, comprising at least one battery cell adjacent to the battery cell, which is arranged at least partially to and / or in a recess of the battery cell by being attached.

[0040] Further advantages, features, and details of the invention will become apparent from the following description, in which several exemplary embodiments of the invention are described in detail with reference to the drawings. The features mentioned in the claims and in the description can be essential to the invention individually or in any combination. The drawings illustrate this by way of example.

[0041] Figure 1 shows a process and

[0042] Figure 2 shows a battery cell.

[0043] The figures use identical reference numerals for the same technical features, even for different embodiments.

[0044] Fig. 1 shows a method for producing a recess 25 in an outer layer 20, in particular an insulating layer 22 of the outer layer 20, of a battery cell 100, in particular for a battery system of a vehicle, comprising the method:

[0045] Providing 110 a battery cell 100, comprising o a battery body 10 for energy storage, o an outer layer 20 surrounding the battery body 10,

[0046] Define 120 a contour K of a recess 25 in the outer layer 20 by scanning and irradiating the outer layer 20 with a laser,

[0047] Heating 130 of the outer layer 20 by scanning and irradiating with the laser, in an area B defined by the contour K, and

[0048] - at least partial detachment 140 of the outer layer 20 in the area B defined by the contour K in order to create the recess 25 in the outer layer 20.

[0049] Within the scope of the invention, it may be advantageous that the provision 110 comprises a manufacturing 111 of the battery cell 100, comprising:

[0050] Manufacturing 112 of the battery body 10 for energy storage,

[0051] 113 Producing the outer layer 20, comprising a housing 21 and an insulating layer 22, on an outward-facing surface of the battery body 10, comprising: o Arranging 114 the housing 21 on the battery body 10, whereby the housing 21 fully surrounds the battery body 10, o Arranging 115 a support substrate 22.1 on the housing 21 and o Applying 116 an adhesive 22.2 to the support substrate 22.1 to obtain the insulating layer 22, comprising the support substrate 22.1 and the adhesive 22.2.

[0052] Within the scope of the invention, it is conceivable that during the defining process 120, the contour K has a self-contained shape on an outwardly facing surface of the outer layer 20, wherein the shape of the contour K is specific for the recess 25. It can also be provided within the scope of the invention that during the defining process 120, the contour K is burned into the outer layer 20, wherein the outer layer 20 is at least partially removed, in particular the insulating layer 22 is completely removed and the housing 21 is not removed.

[0053] It is also conceivable that, in particular before defining 120 and / or heating 130, a pretreatment 119 of the outer layer 20, in particular of the insulating layer 22, is carried out by a solvent which is designed to facilitate the defining 120 and / or heating 130.

[0054] It is also conceivable that the heating 130 of the outer layer 20 by scanning and irradiation includes an area B of the outer layer 20 framed by the contour K, wherein in particular the insulating layer 22, preferably the adhesive 22.2 in the insulating layer 22, is at least partially dissolved by the laser, wherein in particular the adhesive 22.2 is heated so strongly that it dissolves and / or is burned.

[0055] Within the scope of the invention, it is optionally possible that the at least partial detachment 140 involves a mechanical peeling off of at least one outwardly facing part of the

[0056] outer layer 20, in particular the insulation layer 22, encompasses the area B defined by the contour K.

[0057] Furthermore, it may be provided within the scope of the invention that the recess 25 is created by at least partial detachment 140, wherein an outwardly facing bottom 25.1 of the recess 25 is provided for binding 150, in particular fastening and / or gluing, to an adjacent battery cell, wherein in particular the bottom 25.1 has a surface structure, preferably having an increased surface roughness, which provides an increased adhesive force when binding 150.

[0058] With regard to the present invention, it is conceivable that when heating 130 the outer layer 20 by scanning and irradiating it with the laser, the scanning and irradiation are carried out depending on an irradiation pattern, wherein the irradiation pattern is configured to heat the outer layer 20, in particular the insulating layer 22, preferably the adhesive 22.2, such that a heating structure is formed therein, which is in particular specifically, preferably complementarily, designed to match the surface structure that remains at the bottom 25.1 of the recess 25 after at least partial removal 140. Furthermore, it is conceivable that the heating structure and / or surface structure has a varying thickness at least in sections, preferably by means of a plurality of depressions and protrusions.

[0059] Within the scope of the invention, it may be advantageous that the defining 120 and / or heating 130, in particular the irradiation pattern, has a preferred direction, whereby the recess 25, and in particular the surface structure, provides an improved area moment of inertia, especially for connecting 150 to an adjacent battery cell.

[0060] Fig. 2 shows a battery cell 100 (in a section), comprising a battery body 10 for energy storage and an outer layer 20 surrounding the battery body 10, wherein the outer layer 20 comprises a housing 21 and an insulating layer 22.

[0061] The insulating layer 22 can comprise a carrier substrate 22.1 and an adhesive 22.2. The adhesive 22.2 can penetrate and / or surround the (e.g., mesh-like) carrier substrate 22.1 to form the insulating layer 22, particularly after curing. The insulating layer 22 can be composed of two parts and / or comprise a bond between the carrier substrate 22.1 and the adhesive 22.2.

[0062] The recess 25 can be arranged in the outer layer 20, in particular in the insulating layer 22. The contour K can encompass the edges of the recess 25. In this case, the insulating layer 22 was removed in area B by heating 130 and / or peeling 140. The housing 21 can remain.

[0063] The recess 25, in particular the floor 25.1 of the recess 25, may at least partially have the surface structure (not shown).

[0064] Reference symbol list

[0065] 10 battery bodies

[0066] 20 outer layer

[0067] 21 cases

[0068] 22 Insulation layer

[0069] 22.1 Carrier substrate

[0070] 22.2 Adhesive

[0071] 25 Exclusion

[0072] 25.1 Floor

[0073] 100 battery cells

[0074] 110 Provide

[0075] 111 Finishes

[0076] 112 Production

[0077] 113 Manufacturing

[0078] 114 Order

[0079] 115 Order

[0080] 116 orders

[0081] 119 Pretreatment

[0082] 120 Define

[0083] 130 Warming

[0084] 140 replacements

[0085] 150 Connect B Area K Contour

Claims

Patent claims 1. Method for producing a recess (25) in an outer layer (20), in particular an insulating layer (22) of the outer layer (20), of a battery cell (100), in particular for a battery system of a vehicle, comprising the method: Providing (110) a battery cell (100) comprising a battery body (10) for energy storage and an outer layer (20) surrounding the battery body (10), defining (120) a contour (K) of a recess (25) in the outer layer (20) by scanning and irradiating the outer layer (20) with a laser, heating (130) the outer layer (20) by scanning and irradiating it with the laser in an area (B) defined by the contour (K), and at least partially removing (140) the outer layer (20) in the area (B) defined by the contour (K) to produce the recess (25) in the outer layer (20).

2. Method according to claim 1, characterized in that the provision (110) comprises a manufacturing (111) of the battery cell (100), comprising: Manufacturing (112) the battery body (10) for energy storage and manufacturing (113) the outer layer (20), comprising a housing (21) and an insulating layer (22), on an outward-facing surface of the battery body (10), comprising: o arranging (114) the housing (21) on the battery body (10), whereby the housing (21) fully surrounds the battery body (10), o arranging (115) a support substrate (22.1) on the housing (21) and o applying (116) an adhesive (22.2) to the support substrate (22.1) to obtain the insulating layer (22), comprising the support substrate (22.1) and the adhesive (22.2), 3. Method according to one of the preceding claims, characterized in that in the defining (120) the contour (K) has a self-contained shape on an outwardly facing surface of the outer layer (20), wherein the shape of the contour (K) is specific for the recess (25).

4. Method according to one of the preceding claims, characterized in that during the defining (120) the contour (K) is burned into the outer layer (20), wherein the outer layer (20) is at least partially removed, wherein in particular the insulating layer (22) is completely removed and the housing (21) is not removed.

5. Method according to one of the preceding claims, characterized in that, in particular before defining (120) and / or heating (130), a pretreatment (119) of the outer layer (20), in particular the insulating layer (22), is carried out by a solvent which is designed to facilitate the defining (120) and / or heating (130).

6. Method according to one of the preceding claims, characterized in that the heating (130) of the outer layer (20) comprises scanning and irradiating an area (B) of the outer layer (20) framed by the contour (K), wherein in particular the insulating layer (22), preferably the adhesive (22.2) in the insulating layer (22), is at least partially dissolved by the laser, wherein in particular the adhesive (22.2) is heated to such an extent that it dissolves and / or is burned.

7. Method according to one of the preceding claims, characterized in that the at least partial removal (140) comprises a mechanical peeling off of at least an outwardly facing part of the outer layer (20), in particular the insulating layer (22), in the area (B) defined by the contour (K).

8. Method according to one of the preceding claims, characterized in that the recess (25) is created by at least partial detachment (140), wherein an outwardly facing bottom (25.1) of the recess (25) is provided for binding (150), in particular fastening and / or gluing, to an adjacent battery cell, wherein in particular the bottom (25.1) has a surface structure, preferably having an increased surface roughness, which provides an increased adhesive force when binding (150).

9. Method according to one of the preceding claims, characterized in that when heating (130) the outer layer (20) by scanning and irradiating with the laser, the scanning and irradiation is carried out depending on an irradiation pattern, wherein the irradiation pattern is configured to heat the outer layer (20), in particular the insulating layer (22), preferably the adhesive (22.2), in such a way that a heating structure is formed therein, which is in particular specifically, preferably complementarily, designed to the surface structure that remains on the bottom (25.1) of the recess (25) after at least partial removal (140).

10. Method according to one of the preceding claims 8 or 9, characterized in that the heating structure and / or surface structure has a varying thickness at least section by section, preferably by a plurality of depressions and elevations.

11. Method according to one of the preceding claims, characterized in that the defining (120) and / or heating (130), in particular the irradiation pattern, has a preferred direction, whereby the recess (25), and in particular the surface structure, provides an improved area moment of inertia, in particular for connecting (150) to an adjacent battery cell.

12. Battery cell (100) comprising a battery body (10) for energy storage and an outer layer (20) surrounding the battery body (10), wherein the outer layer (20) has at least one recess (25) which was produced by the method according to one of the preceding claims.

13. Battery system comprising at least one battery cell (100) according to the preceding claim.

14. Battery system, in particular for a vehicle, comprising at least one battery cell adjacent to the battery cell (100), which is arranged at least partially to and / or in a recess (25) of the battery cell (100) by means of a connection (150).

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