Method for producing a battery cell arrangement and battery cell arrangement

Abstract

The invention relates to a method for producing a battery cell arrangement (10). The battery cell arrangement (10) has a plurality of battery cells (14) and a receptacle (12) for receiving the plurality of battery cells (14). Each battery cell (14) has a housing (22). The housing (22) has a main body (32) and a coating (34). The method has the steps of: preparing each battery cell (14) of the battery cell arrangement (10) for establishing an adhesive bond (20) by producing a plurality of dimples (24) in the housing (22) by means of a laser beam, wherein at least 20% of the dimples (24), preferably each dimple (24), penetrate the coating (34); arranging the plurality of battery cells (14) in the receptacle (12); and establishing the adhesive bonds (20).

Description

[0001] Title: Method for manufacturing a battery cell assembly and battery cell assembly

[0002] Description

[0003] The invention relates to a method for manufacturing a battery cell arrangement and a battery cell arrangement.

[0004] A battery cell assembly typically consists of multiple battery cells and a housing. During the manufacturing process, gaps often occur between adjacent battery cells, which are usually filled with an adhesive. This adhesive creates bonds that connect the battery cells to the housing and to each other. These bonds secure the battery cells within the housing and prevent unwanted movement of the individual cells relative to one another.

[0005] The strength of adhesion between the adhesive and a battery cell can depend, for example, on the surface roughness and / or cleanliness of the battery cell surface. Often, to increase adhesion, the surfaces of the battery cells are roughened.

[0006] The invention is based on the objective of providing a method for manufacturing a battery cell arrangement and providing a battery cell arrangement, each of which has improved properties, in particular enabling better protection of the battery cells against unintentional displacement.

[0007] The invention solves this problem by providing a method with the features of claim 1 and a battery cell arrangement with the features of claim 14. Advantageous embodiments and further developments of the invention are set forth in the dependent claims.

[0008] A method according to the invention serves to manufacture a battery cell assembly. The battery cell assembly comprises a plurality, for example 2, 3, 6, 9 or 15, of battery cells and a receptacle for receiving the plurality of battery cells. Each battery cell has a housing. The housing comprises a base body and a coating. The method comprises: preparing each battery cell of the battery cell assembly for the formation of an adhesive bond by creating a plurality, in particular a plurality, of pits in the housing using a laser beam, wherein at least 20% of the pits, preferably each pit, penetrate the coating, in particular completely; arranging the plurality of battery cells in the receptacle; and forming the adhesive bonds using an adhesive.

[0009] Because at least 20% of the dimples, preferably each dimple, penetrate the coating, the substrate can be exposed through the dimple. In other words, the coating can be locally removed from the substrate through the dimple. This allows each dimple to have a depth that is advantageous for creating the adhesive bond. In particular, such a deep dimple ensures the adhesion of the adhesive to the battery cell. This allows for the creation of an adhesive bond with high adhesion, thus improving the protection of the battery cells against unintentional displacement.

[0010] Another aspect of the process is that, due to the dimples penetrating the coating, the adhesive for creating the bond makes direct contact with the substrate. The substrate can be made of a material to which the adhesive exhibits higher adhesion than to the coating material. This can further increase the adhesion of the bond. Another aspect of the process is that, due to the dimples, the surface area of ​​the housing for the adhesive bond is increased. This can further increase the adhesion of the bond.

[0011] Another aspect of the process may be that the dimples can reduce the risk of creating a faulty adhesive bond.

[0012] Another aspect of the process may be that by creating the dimples using the laser beam, the surface is cleaned using the laser beam to prepare for the adhesive bond.

[0013] Another aspect of the process is that the dimples ensure that the adhesive bonds have uniform properties. In other words, the dimples can enable homogeneous adhesive bond properties for all bonded battery cells. This can result in less variation in the properties of the adhesive bonds, particularly adhesion, from battery cell to battery cell.

[0014] Another aspect of the process may be that the dimples reduce the risk of faulty adhesion of the adhesive to the battery cells, thereby achieving higher corrosion protection of the battery cells through the adhesive.

[0015] The battery cell assembly can also be referred to as a battery module or battery pack, especially a rechargeable battery pack. After the battery cell assembly has been manufactured, the battery cells can be electrically connected to each other in parallel or in series.

[0016] A battery cell can be understood as a storage device for electrical energy. In particular, a battery cell can be understood as an accumulator. The battery cell can be designed as a lithium-ion accumulator. The battery cell can be cylindrical. Preferably, the battery cell can be a cylindrical lithium-ion accumulator.

[0017] The housing can be described as a cage, specifically a battery cage. Multiple battery cells can be inserted into the housing.

[0018] The housing can be made of metal. The base body can be made of metal. The base body can be coated. The coating can be a metallic coating. The material of the base body can differ from the material of the coating. Additionally or alternatively, the material composition of the base body can differ from the material composition of the coating. The material of the base body can be better suited for creating the adhesive bond than the material of the coating.

[0019] The housing can have a thickness ranging from 0.1 mm (millimeters) to 1.5 mm, particularly from 0.4 mm to 0.8 mm. The coating can have a thickness ranging from 1 pm (micrometers) to 15 pm.

[0020] A dimple can be understood as a trough-shaped indentation. These dimples can also be referred to as boreholes. Each dimple can have a maximum depth and a maximum width. Dividing the maximum depth of the dimple by its maximum width can yield a value in the range of 0.5 to 20, particularly 1 to 10. This advantageously allows for high adhesion of the adhesive bond. Each dimple can have a depth of at least 15 µm relative to the corrosion protection thickness. Each dimple can have a maximum depth of 50 µm.

[0021] Creating multiple pits can be described as structuring the battery cell. A continuous ablation process, such as engraving / indentation, can also be relevant. Creating multiple pits can be achieved by ablating or removing the coating. Creating multiple pits can also be achieved by drilling with a laser beam. In particular, creating multiple pits can be achieved primarily by ablation rather than by remelting the coating. Preferably, creating multiple pits does not involve remelting the coating.

[0022] By creating the pits, the underlying structure can be exposed, particularly in certain areas. Multiple pits can be created in such a way that the underlying structure is accessible from the outside via the pit.

[0023] The laser beam can have a rotationally symmetric beam profile. Advantageously, this allows for direction-independent pitting. Alternatively, the laser beam profile can have a preferred direction. The laser beam can be a single-mode or multi-mode laser beam. The laser beam can have a diffraction coefficient M. 2 exhibit a diffraction coefficient of less than 1.8, particularly in the range of 1 to 1.4, especially if the laser beam is a single-mode laser beam. Alternatively, the laser beam may have a diffraction coefficient M 2exhibiting values ​​greater than 2, particularly 4, especially if the laser beam is a multi-mode laser beam. If the laser beam is a single-mode laser beam, the method may be less sensitive to unwanted shifts in the laser beam's focus direction due to a high Rayleigh length. If the laser beam is a multi-mode laser beam, a more uniform intensity distribution may result in a more uniform vaporization rate in a spot created by the laser beam upon impact with the housing.

[0024] The laser beam can be a pulsed laser beam. Advantageously, this allows the laser beam to act on the battery cell with high intensity and simultaneously moderate average power. This enables the creation of the pits with minimal heat input into the battery cell. In particular, the heat input can be targeted precisely to a specific surface of the battery cell.

[0025] The laser beam can be an ultrashort pulse laser beam. An ultrashort pulse laser beam is defined as one where the pulse duration of the laser pulses is in the picosecond or femtosecond range. The pulse duration of the laser pulses means that each laser pulse has a specific duration. Alternatively, the pulsed laser beam can be a quasi-continuous wave laser beam. A quasi-continuous wave laser beam can be generated using a continuous wave laser source operating in pulsed mode. This advantageously reduces the complexity of the system for generating the pulsed laser beam.

[0026] The pulse duration of the laser pulses of the laser beam can have a value in the range of 200 fs (femtoseconds) to 1 ps (microseconds), in particular 200 fs to 500 ns (nanoseconds).

[0027] The pulse repetition frequency of the laser pulses of the laser beam can have a value in the range of 1 kHz (kilohertz) to 4 MHz (megahertz). The laser pulses of the laser beam can be arranged in groups (bursts). A burst mode can be 2 times to 40 times, in particular 6 times to 10 times.

[0028] The pulse energy of each laser pulse in the laser beam can range from 4 pJ (microjoules) to 10 mJ (millijoules). Specifically, if one of the pits is created with a single laser pulse, the pulse energy can range from 4 pJ to 10 mJ. If the pulse duration of the laser beam is in the nanosecond range, the pulse energy of each laser pulse can range from 500 pJ to 10 mJ. If the pulse duration of the laser beam is in the picosecond or femtosecond range, the pulse energy of each laser pulse can range from 4 pJ to 300 pJ.

[0029] If the pulse duration of the laser beam is in the nanosecond range, the average power of the laser beam can range from 60 W to 1000 W. If the pulse duration of the laser beam is in the picosecond or femtosecond range, the average power of the laser beam can range from 20 W to 400 W.

[0030] For example, the laser beam can be a nanosecond laser beam. A laser beam can be understood to be a nanosecond laser beam if the pulse duration of the laser pulses of the laser beam has a value in the range of 3 ns to 2000 ns, in particular 20 ns to 500 ns; and the pulse repetition frequency of the pulsed laser beam has a value in the range of 1 kHz to 4 MHz, in particular 10 kHz to 1600 kHz; and the average power of the pulsed laser beam has a value in the range of 20 W (watts) to 5000 W, in particular 200 W to 1000 W.

[0031] For example, the laser beam can be a quasi-continuous-wave laser beam. A laser beam can be understood as a quasi-continuous-wave laser beam if it is a single-mode laser beam; and the pulse duration of the laser pulses of the laser beam has a value in the range of 500 ns to 1 ms (milliseconds), in particular 1 ps to 100 ps; and the average power of the pulsed laser beam has a value in the range of 500 W to 4000 W, in particular 2000 W to 3000 W; and the peak power of the laser pulses of the laser beam has a value in the range of 1000 W to 10000 W, in particular 2000 W to 4000 W.

[0032] During the production of the dimples, the laser beam can be focused onto one of the battery cells such that the laser beam strikes the battery cell with a beam parameter product in the range of 0.38 mm*mrad (millimeters*milliradians) to 16 mm*mrad. Preferably, the laser beam can strike the battery cell with a beam parameter product in the range of 0.4 mm*mrad to 0.6 mm*mrad. The laser beam can be focused onto the battery cell such that, if the laser beam is a single-mode laser beam, it strikes the battery cell with a beam parameter product of less than or equal to 0.6 mm*mrad, or, if the laser beam is a multi-mode laser beam, it strikes the battery cell with a beam parameter product of less than or equal to 4 mm*mrad, in particular 2 mm*mrad.

[0033] During the production of the dimples, the laser beam can be focused on one of the battery cells such that the beam diameter of the laser beam on the battery cell has a value in the range of 25 pm to 500 pm, in particular 30 pm to 70 pm.

[0034] During the creation of the dimples, the laser beam can be focused on one of the battery cells in such a way that a peak intensity of the laser beam on the battery cell reaches an amount in the range of 5 MW / cm². 2 (Megawatts per square centimeter) up to 500 MW / cm² 2 , especially 90 MW / cm² 2 up to 190 MW / cm² 2 , exhibits.

[0035] The laser beam can be guided across the battery cells using a scanner optic to create the dimples. Advantageously, this allows the laser beam to be guided across the battery cells at high speed. Alternatively, the laser beam can be focused onto one of the battery cells using a fixed optic with a magnification ratio of 1:1 to 5:1, particularly 1.5:1 to 2:1, to create the dimples.

[0036] The laser beam can be passed over the battery cells multiple times to create the pits. In other words, the pits can be created by one pass, two passes, or several passes. The laser beam can have a wavelength in the range of 800 nm (nanometers) to 1200 nm, particularly 1030 nm to 1070 nm. Alternatively, the laser beam can have a wavelength in a visible spectral range, for example, 515 nm.

[0037] The pitting can be produced using an inert process gas. This inert process gas could be, for example, argon or nitrogen. Advantageously, this prevents oxidation of the housing during the pitting process.

[0038] During the dimple production process, the processing position of the laser beam and / or the geometry, particularly an edge and / or circumferential geometry, of the battery cell being processed by the laser beam can be measured using a monitoring sensor. This advantageously allows for tolerance compensation, higher precision, and reduced scrap. The monitoring sensor can include a camera and / or an optical coherence tomography sensor. The processing position of the laser beam can be controlled based on the measured processing position and / or the geometry of the battery cell. Automatic path programming can be performed based on the measured processing position and / or the geometry of the battery cell.

[0039] It is also conceivable that the creation of the dimples could be monitored using a camera-based sensor. This sensor could be used to control the position of the laser beam's point of impact on one of the battery cells, thus preventing faulty processing of the cells.

[0040] The creation of the dimples can be achieved using a distance sensor to measure the surface of the battery cells. The processing position of the laser beam can be controlled depending on the measured surface area of ​​the battery cell. This advantageously ensures high contour accuracy. The distance sensor can be, for example, a capacitive sensor, an optical coherence tomography sensor, or a laser triangulation sensor.

[0041] During the dimple formation process, one of the battery cells being treated with the laser beam and a focusing optic, which focuses the laser beam onto the battery cell for this purpose, can move relative to each other. In other words, the dimple formation can be performed on-the-fly. This allows for faster throughput times.

[0042] The dimples can be produced with a feed rate ranging from 1 m / s (meters per second) to 50 m / s, particularly from 10 m / s to 30 m / s. The feed rate may depend on the material thickness of the housing, especially the coating.

[0043] The pitting can be achieved using multiple laser beams. These multiple laser beams can simultaneously strike one of the battery cells for this purpose. This advantageously allows the pitting to be completed in a shorter time.

[0044] In a battery cell, two adjacent pits can be spaced apart by a distance ranging from one to 20 times, particularly 1.3 to 2 times, the diameter of one of the pits, preferably on the surface of the casing. In other words, two adjacent pits can be spaced apart by a distance ranging from one to 20 times, particularly 1.3 to 2 times, the diameter of one of the pits. This allows for particularly strong and stable adhesive bonds.

[0045] Each battery cell can have an outer surface or a surface that is irradiated with the laser beam for the purpose of creating the pits. This allows the pits to be created on the outer surface or the surface of each battery cell.

[0046] The adhesive bonds can be created using the adhesive. The adhesive can be applied to create the bond between one of the battery cells and the holder. Additionally or alternatively, the adhesive can be applied to create the bond between two adjacent battery cells arranged in the holder.

[0047] The adhesive can be a reactive casting resin, a two-component polyurethane thermal adhesive, and / or a thixotropic sealant. The adhesive can be made of polyurethane, epoxy, silicone, acrylic, or acrylate materials. The adhesive can serve to electrically insulate the battery cells arranged in the housing from one another. The adhesive can form an insulating layer around each battery cell.

[0048] The adhesive can serve to protect the battery cells from damage caused by impact. In particular, the adhesive can act as a damper for the battery cells. If an impact acts on the battery cell assembly, the adhesive can reduce, and especially dampen, the resulting impact force on the battery cells.

[0049] The adhesive can be used to dissipate heat from the battery cells.

[0050] The adhesive bond can be created by the adhesive contacting the base body. The bond can be created by contacting the dimples with the adhesive. The bond can be created by placing the adhesive in the dimples. The bond can be created by filling or completely filling the dimples with the adhesive. The bond can be created within a housing section of the housing where the dimples are formed.

[0051] The adhesive bonds can be used to bond each battery cell to the housing. In other words, the adhesive bonds can be positioned between the majority of battery cells and the housing. The adhesive bonds can be used to bond the battery cells together.

[0052] The adhesive bond can be located between one of the battery cells and a component, in particular another battery cell or the housing of the battery cell assembly. In other words, the adhesive bond can serve to connect, fix, and / or secure one of the battery cells to the component.

[0053] The majority of the dimples of one of the battery cells can be arranged in a surface section of the casing. The adhesive bond can be made in this surface section.

[0054] The procedure may include, prior to preparing the battery cells: providing the majority of battery cells; and providing the recording.

[0055] In a further development of the process, the base body is made of a corrosive material. Additionally or alternatively, the coating is made of a corrosion-resistant material. This process allows the base body to be protected from corrosion by means of the adhesive bond. In other words, the adhesive bond can provide corrosion protection for the base body. The coating can also provide corrosion protection for the base body.

[0056] In a further development of the process, the base body is formed from a material containing at least 50% iron by weight, in particular 60% by weight. Additionally or alternatively, the coating is formed from a material containing at least 50% nickel by weight, in particular 60% by weight. Iron and / or nickel can exhibit high electrical and thermal conductivity, making such a material particularly suitable for use in battery cells.

[0057] The material from which the base body is formed may contain a maximum of 100% iron by weight. The material from which the coating is formed may contain a maximum of 100% nickel by weight.

[0058] In a further development of the process, the laser beam is a pulsed laser beam. This allows the pits to be created in one of the battery cells with a small heat-affected zone. In particular, the small heat-affected zone reduces the risk of damaging the battery cells during the pitting process.

[0059] In a further development of the method, each laser pulse of the pulsed laser beam strikes with a fluence of at least 2 J / cm². 2 (Joules per square centimeter), particularly for the purpose of creating one of the dimples, on the housing. With such a fluence, a dimple can be created quickly and effectively in the housing. Each laser pulse of the pulsed laser beam can be generated with a fluence in the range of 2 J / cm². 2 up to 10 J / cm 2 hit the casing.

[0060] In a further development of the method, each dimple is created using a plurality, for example 2 or 10, of laser pulses. Advantageously, this allows for the creation of a dimple with a high aspect ratio.

[0061] In a further development of the process, the coating has a first side and a second side. The first side faces away from the substrate. The second side faces the substrate. Each dimple penetrates the coating, forming a first opening located on the first side of the coating and a second opening located on the second side of the coating. Each dimple penetrates the coating such that the first opening is larger than the second opening. This allows for particularly high adhesion of the adhesive to the housing.

[0062] The diameter of the first opening can be larger than the diameter of the second opening. Each dimple can extend from the first side to the second side.

[0063] In a further development of the process, each dimple has a depth greater than the thickness of the coating. This allows each dimple to extend partially into the substrate. As a result, the adhesive bond can contact the substrate over a larger surface area.

[0064] In a further development of the method, the majority of pits are arranged in a surface section of the casing. For cylindrical cells, this surface section has a size in the range of 100 cm². 2 up to 450 cm 2 , especially 200 cm 2 up to 300 cm 2Prismatic cells, in particular, can also have larger surface areas. Such large surface areas are ideal for attaching the battery cells using adhesive bonding.

[0065] In a further development of the process, a burr is formed during the production of each dimple. This burr increases the adhesion of the adhesive to the housing. Each dimple can be bordered by a burr on the housing.

[0066] In a further development of the method, each burr has a size, in particular a protrusion or a length, with a value in the range of 3 pm to 30 pm, preferably 5 pm to 15 pm. For such sizes, an optimal increase in the adhesion of the adhesive to the housing can be achieved.

[0067] In a further development of the process, the majority of the dimples are produced in a regular arrangement. This prevents the adhesive bond from adhering to the housing with varying strengths in different locations. In particular, it ensures that the adhesive bond adheres homogeneously to the housing. Therefore, unwanted local detachment of the adhesive bond from the housing can be avoided. The regular arrangement can be a structured or systematic arrangement of the dimples according to a rule or pattern. A regular arrangement can be understood as one in which the arrangement of the dimples follows a recognizable and repeatable pattern, especially a linear or grid structure.

[0068] For example, the dimples in each battery cell can be arranged in a rectangular or triangular grid. Alternatively, the dimples in each battery cell can be arranged in a square, circular, or spiral pattern.

[0069] The pits in each battery cell can be spaced equally apart.

[0070] In a further development of the process, all the dimples have the same shape. This can be advantageous for homogeneous adhesion of the adhesive to the housing.

[0071] A battery cell arrangement according to the invention comprises a plurality of battery cells, a receptacle, and a plurality of adhesive joints. The plurality of battery cells are arranged in the receptacle. The plurality of adhesive joints are designed to prevent unintentional displacement of the battery cells relative to one another. Each battery cell has a housing. Each housing has a base body and a coating. Each housing has a plurality of dimples for creating the adhesive joint. Each dimple penetrates the coating.

[0072] The battery cell assembly can be manufactured using a previously described method. The previously given description of the methods can apply to identical or functionally equivalent features of the battery cell assembly.

[0073] Further advantages and advantageous embodiments of the invention can be seen from the figures, their description, and the claims. All features disclosed in the figures, their description, and the claims can be essential to the invention, both individually and in any combination. The figures show:

[0074] Fig. 1 shows a schematic oblique view of a battery cell arrangement with a plurality of battery cells,

[0075] Fig. 2 is a schematic oblique view of a battery cell of the battery cell arrangement, Fig. 3 is a schematic sectional view of the battery cell along a section line III-III according to Fig. 2, and

[0076] Fig. 4 shows a detailed view of area IV of Fig. 3.

[0077] Fig. 1 shows a battery cell arrangement 10. The battery cell arrangement has a receptacle 12 and at least one battery cell 14. In the illustrated embodiment, the battery cell arrangement 10 has nine battery cells 14. However, any other number of battery cells 14 is also conceivable.

[0078] The battery cell arrangement 10 is designed to be used in an electrical device to supply the device with electrical current. The battery cells 14 are electrically connected to each other in parallel or in series.

[0079] Each battery cell 14 is designed to store electrical current. Each battery cell 14 is a lithium-ion battery. Each battery cell 14 is cylindrical in shape.

[0080] The receptacle 12 is bowl-shaped. The receptacle 12 is rectangular. The battery cells 14 are inserted into the receptacle 12. In other words, the battery cells 14 are held by the receptacle 12. The receptacle 12 at least partially surrounds the battery cells 14.

[0081] The battery cell assembly 10 has an adhesive 16. The adhesive 16 is applied to the spaces 18 between the battery cells 14 and to the spaces between the battery cells 14 and the receptacle 12. The battery cell assembly 10 is assembled by filling a portion of the adhesive 16 into the receptacle 12, inserting the battery cells 14 into the receptacle 12, and filling the spaces 18 between the battery cells 14 that are not yet filled with adhesive 16 with the remaining portion of the adhesive 16.

[0082] By filling the spaces 18 with the adhesive 16, the adhesive 16 protects the battery cells 14 from unwanted displacement when a shock acts on the battery cell arrangement 10.

[0083] The adhesive 16 is a two-component polyurethane thermally conductive adhesive. The adhesive 16 insulates the battery cells 14 from each other and from the receptacle 12. Additionally, the adhesive 16 conducts heat, which can be generated in the battery cells 14, particularly during charging or discharging, from the battery cells 14 to the receptacle 12. Thus, the adhesive 16 serves to dissipate heat from the battery cells 14.

[0084] Adhesive bonds 20 are created using the adhesive 16. Each adhesive bond 20 connects a battery cell 14 of the battery cell arrangement 10 to a component of the battery cell arrangement 10. In other words, each battery cell 14 is connected by means of an adhesive bond 20 to a battery cell 14 adjacent to the battery cell 14 of the battery cell arrangement 10 or to the receptacle 12.

[0085] Fig. 2 shows a single battery cell 14 of the battery cell arrangement 10. The battery cells 14 of the battery cell arrangement 10 are identical in construction. Therefore, the description in Fig. 2 applies to the battery cell arrangement 10.

[0086] The battery cell 14 shown in 2 also applies to the other battery cells 14 of the battery cell arrangement 10.

[0087] The battery cell 14 has a housing 22. The housing 22 encloses an interior space. The housing 22 can be a closed housing 22. In other words, the housing 22 has no opening leading into the interior space.

[0088] The battery cell 14 has a plurality of pits 24. The pits 24 serve to increase the adhesion of the adhesive 16 to the battery cell 14, which is why a particularly stable and secure adhesive bond 20 can be produced.

[0089] The pits 24 are arranged on a surface of the battery cell 14. The pits 24 are arranged in a surface section 26 of the housing 22. The surface section 26 has a size of 200 cm². 2 up to 300 cm 2 .

[0090] The 24 dimples are arranged in a regular pattern. The 24 dimples are arranged in a rectangular grid, specifically in a square pattern. The 24 dimples are equally spaced apart.

[0091] Fig. 3 shows a sectional view of the battery cell 14. In the interior 28 of the battery cell 14, at least one component 30 is arranged which enables the battery cell 14 to store electrical energy.

[0092] The housing 22 has a base body 32 and a coating 34. The base body 32 is coated with the coating 34. The coating 34 has a thickness 36 with a value in the range of 3 pm to 10 pm. The base body 32 has a thickness 38 with a value in the range of 0.2 mm to 1 mm.

[0093] The base body 32 is made of a corrosive material. The coating 34 is made of a corrosion-resistant material. The coating 34 serves as corrosion protection for the base body 32. In the illustrated embodiment, the base body 32 is made of a material with an iron content ranging from 50% to 100% by weight. The coating 34 is made of a material with a nickel content ranging from 50% to 100% by weight.

[0094] Two adjacent pits 24 are spaced apart by a distance 40, with a value in the range of 1.3 to 2 times the diameter 42 of one of the two pits 24. The diameter 42 of a pit 24 can also be referred to as the width of the pit 24. All pits 24 of the battery cell 14 have the same shape.

[0095] Fig. 4 shows a detailed view of a pit 24 of the battery cell 14. The pits 24 of the battery cell 14 are identical. Therefore, the description of the pit shown in Fig. 4 also applies to the other pits of the battery cell 14.

[0096] The dimple 24 completely penetrates the coating 34. The dimple 24 has a depth 44, which is greater than the thickness 36 of the coating 34. The depth 44 of the dimple 24 can be determined without considering any burr. Therefore, the dimple 24 extends partially into the base body 32.

[0097] During the production of the dimple 24, a ridge 46 is formed. The dimple 24 is bounded by the ridge 46. The ridge 46 has a size 48 with a value in the range of 3 pm to 30 pm, preferably 5 pm to 15 pm. The size 48 of the ridge 46 can be disregarded when determining the depth 44 of the dimple 24.

[0098] The coating 34 has a first side 50 and a second side 52. The first side 50 faces away from the base body 32. The second side 52 faces the base body 32. The pit 24 penetrates the coating 34, forming a first opening 54 located on the first side 50 of the coating and a second opening 56 located on the second side 52 of the coating 34. The diameter 58 of the first opening 54 is larger than the diameter 60 of the second opening 56. The diameter 58 of the first opening 54 can be determined without considering the burr 46.

[0099] Each dimple 24 is created using a laser beam. By irradiating the battery cell 14 with the laser beam, material is removed from the housing 22, forming a dimple 24. The dimple 24 can be created by ablating or removing the coating 34 using the laser beam. This locally exposes the base body 32, allowing access from the outside through the dimple 24.

[0100] The laser beam can have a rotationally symmetric beam profile. The laser beam can be a single-mode laser beam with a diffraction coefficient M. 2The laser beam for creating a dimple 24 can be a pulsed laser beam. The pulse duration of each laser pulse can be in the range of 200 fs to 500 ns. The pulse repetition rate of the laser pulses can be in the range of 1 kHz to 4 MHz. The pulse energy of each laser pulse can be in the range of 4 pJ to 10 mJ. The average power of the laser beam can be in the range of 20 W to 1000 W. The laser beam can have a wavelength in the range of 800 nm to 1200 nm.

[0101] During the creation of the dimple 24, the laser beam is focused on the battery cell 14 in such a way that the laser beam with a beam parameter product in a range of 0.38 mm*mrad (millimeter*milliradian) to 16 mm*mrad hits the battery cell 14.

[0102] During the production of the dimple 24, the laser beam is focused on the battery cell 14 such that the beam diameter of the laser beam on the battery cell 14 has a value in the range of 25 pm to 500 pm, in particular 30 pm to 70 pm.

[0103] During the creation of the dimple 24, the laser beam is focused on the battery cell 14 in such a way that a peak intensity of a laser pulse of the laser beam on the battery cell 14 has an amount in the range of 5 MW / cm². 2 up to 500 MW / cm² 2 exhibits.

[0104] During the creation of the dimple 24, the laser beam is focused onto the battery cell 14 in such a way that each laser pulse of the pulsed laser beam has a fluence with a value in the range of 2 J / cm². 2 up to 10 J / cm 2the housing 22. The production of the dimples 24 of the battery cell 14 shown in Fig. 2 is carried out with a feed rate in the range of 1 m / s to 50 m / s, in particular 10 m / s to 30 m / s. In other words, the laser beam is guided over the battery cell 14 at a speed in the range of 1 m / s to 50 m / s, in particular 10 m / s to 30 m / s.

[0105] The laser beam is focused onto the battery cell 14 shown in Fig. 2 using a focusing optic to create the pits 24. During the pitting process, the battery cell 14 moves relative to the focusing optic. This allows the pitting to be created on-the-fly, thus reducing the cycle time of the battery cell 14.

[0106] During the production of the dimples 24 of the battery cell 14 shown in Fig. 2, the processing position of the laser beam is measured by means of a monitoring sensor. This allows the processing position to be adjusted if a deviation occurs, thereby achieving higher precision.

[0107] In an alternative embodiment not shown, the pitting can be produced by simultaneously irradiating the battery cell 14 with a plurality of laser beams. The laser beams can be identical. In other words, the laser beams can have the same beam properties.

[0108] By creating the dimples 24, the battery cell 14 is prepared for the creation of the adhesive bond 20.

[0109] During the formation of the adhesive bonds 20, the adhesive 16 is applied to each dimple 24 of the battery cells 14 of the battery cell assembly 10, so that the adhesive 16 contacts the base body 32. This fills the dimples 24 with the adhesive 16. The dimples 24 and the ridge 46 ensure that the adhesive 16 adheres particularly well to each battery cell 14, resulting in stable and secure adhesive bonds 20.

Claims

Patent claims 1. A method for manufacturing a battery cell assembly (10), wherein the battery cell assembly (10) comprises a plurality of battery cells (14) and a receptacle (12) for receiving the plurality of battery cells (14), wherein each battery cell (14) has a housing (22), the housing (22) comprising a base body (32) and a coating (34), the method comprising: preparing each battery cell (14) of the battery cell assembly (10) for the formation of an adhesive bond (20) by forming a plurality of pits (24) in the housing (22) by means of a laser beam, wherein at least 20% of the pits (24), preferably each pit (24), penetrates the coating (34), arranging the plurality of battery cells (14) in the receptacle (12), and forming the adhesive bonds (20).

2. Method according to claim 1, wherein the base body (32) is made of a corrosive material, and / or wherein the coating (34) is made of a corrosion-resistant material.

3. Method according to any of the preceding claims, wherein the base body (32) is formed from a material having a content of at least 50 wt%, in particular 60 wt%, iron, and / or wherein the coating (34) is formed from a material having a content of at least 50 wt%, in particular 60 wt%, nickel.

4. Method according to any of the preceding claims, where the laser beam is a pulsed laser beam.

5. Method according to claim 4, where each laser pulse of the laser beam has a fluence of at least 2 J / cm² 2 meets the casing (22).

6. Method according to claim 4 or 5, wherein each pit (24) is produced with a plurality of laser pulses.

7. Method according to any one of the preceding claims, wherein the coating (34) has a first side (50) facing away from the base body (32) and a second side (52) facing the base body (32), wherein each dimple (24) penetrates the coating (34) forming a first opening (54) located on the first side (50) of the coating (34) and a second opening (56) located on the second side (52) of the coating (34), wherein each dimple (24) penetrates the coating (34) in such a way that the first opening (54) is larger than the second opening (56).

8. Method according to any of the preceding claims, wherein each dimple (24) has a depth (44) whose value is greater than a value of a thickness (36) of the coating (34).

9. Method according to any of the preceding claims, wherein the majority of pits (24) are arranged in a surface section (26) of the housing (22), wherein the surface section (26) has a size with a value in the range of 100 cm 2 up to 450 cm 2 exhibits.

10. Method according to any of the preceding claims, wherein a ridge (46) is formed during the production of each dimple (24).

11. Method according to claim 10, wherein each ridge (46) has a size (48) with a value in the range of 3 pm to 30 pm, preferably 5 pm to 15 pm.

12. Method according to any of the preceding claims, the majority of dimples (24) are produced in a regular arrangement.

13. Method according to any of the preceding claims, wherein all dimples (24) have the same shape.

14. Battery cell arrangement (10), comprising: a plurality of battery cells (14), a receptacle (12) in which the majority of battery cells (14) are arranged, and a plurality of adhesive connections (20) for preventing an unintentional displacement of the battery cells (14) relative to each other, wherein each battery cell (14) has a casing (22), wherein each housing (22) has a base body (32) and a coating (34), wherein each housing (22) has a plurality of dimples (24) for making the adhesive bond (20), wherein at least 20% of the pits (24), preferably each pit (24), penetrates the coating (34).

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