Battery cell stack, battery cell module and method for manufacturing the battery cell module

Abstract

The invention relates to a battery cell stack comprising a plurality of battery cells (12) arranged side by side, wherein each of the battery cells (12) has a prismatic cell housing (14) with a connection surface (16) by means of which the cell housing (14) can be attached to at least one receptacle, and wherein the cell housing (14) of each of the battery cells (12) is at least partially surrounded by an insulating film (24). The invention further relates to a battery cell module comprising a battery cell stack and a receptacle, as well as a method for manufacturing such a battery cell module. The invention is based on the objective of enabling a fixed and electrically insulating connection of battery cells (12) contained in the battery cell stack to a receptacle in a simple and cost-effective manner. The problem is solved by providing an insulating layer (28, 28') that differs from the insulating film (24) at at least one edge (26, 26') of the connection surface (16) of each of the battery cells (12).

Description

[0001] The invention relates to a battery cell stack comprising a plurality of battery cells arranged side by side, each battery cell having a prismatic cell housing with a mounting surface by means of which the cell housing can be attached to at least one receptacle, and wherein the cell housing of each battery cell is at least partially surrounded by an insulating film. In particular, the invention relates to a battery cell stack of a traction battery for a motor vehicle. The invention further relates to a battery cell module comprising at least one such battery cell stack and at least one receptacle for the battery cell stack. The invention also relates to a method for manufacturing such a battery cell module.

[0002] Lithium-ion battery systems are preferably used as traction batteries in hybrid electric vehicles (HEVs) and electric vehicles (EVs) because they have a relatively high specific energy density and a low self-discharge rate. Furthermore, lithium-ion battery systems advantageously do not exhibit a memory effect.

[0003] To achieve the performance and energy data required for operating the drive motor of a hybrid electric vehicle or electric vehicle, a large number of individual battery cells, each with a voltage between 2 V and 5 V, particularly between 4 V and 5 V, are connected in series or parallel, resulting in a total battery system voltage of more than 200 V, more than 300 V, more than 400 V, or even more than 800 V. Battery systems with a voltage between 200 V and 1200 V are frequently used, with voltages between 400 V and 800 V being particularly preferred. For electrical insulation, the battery cells are typically surrounded by an insulating film, commonly referred to as blue film.The insulating film is arranged on the surfaces of the cell housing of each of the battery cells, whereby at least the pole sections of the battery cells remain uncovered by a covering with the insulating film in order to be able to make electrically conductive contact.

[0004] The battery cells used in a battery system are typically grouped into a battery cell module, which, in addition to the battery cells themselves, has at least one mounting for them. Several of these battery cell modules are usually combined to form a battery system that provides the performance and energy data required to operate the drive motor.

[0005] The battery cells of a battery cell module are attached to at least one mounting. This attachment is typically achieved using an adhesive bond. Specifically, an adhesive layer is provided between the insulating film applied to the mounting surface of the battery cell casings and the mounting. Such a connection ensures good electrical insulation and secure bonding of the battery cells. However, the insulating layer exhibits low strength, particularly low compressive strength.Sudden, high forces acting on the battery cells, and / or repeated forces, such as those resulting from driving a vehicle containing the battery cell module over uneven terrain, can lead to structural failure of the insulating film, its connection to the battery cell, and / or its connection to the adhesive layer. To prevent this damage, it is possible to omit the application of the insulating film, at least in locally limited sections of the bonding surface. The adhesive layer can then be applied between the battery cell housing and the mounting surface in these sections. This avoids the weakening of the bond caused by the insulating film. However, the cell housing is either not electrically insulated or only relatively weakly insulated in these sections.

[0006] A battery cell housing with an insulating film is known, for example, from DE 10 2021 131 034 A1. This document relates to the battery cell housing of a battery system, wherein the battery system comprises at least one battery cell and a battery control unit. A voltage tap area is provided on the outside of the battery cell housing, which can be electrically connected to, or is connected to, the battery control unit. Except for the voltage tap area, the battery cell housing is covered with an electrically insulating layer. The electrically insulating layer can, for example, be designed as a film. Mechanical failure of the connection of the insulating layer to a mounting is not addressed.

[0007] WO 2023 / 216033 also discloses a battery cell with a battery cell housing, wherein the battery cell housing has an opening, at least one connection surface, and insulation. The insulation comprises an insulating film and an insulating coating. The insulating coating covers at least a section of one of the connection surfaces, and the insulating film covers at least the area of ​​the cell housing that lies outside the insulating coating. The insulating coating can, in particular, cover the entire connection surface or a locally limited section in a central region of the connection surface.

[0008] Furthermore, a component carrier for microelectronic components is known from US 2020 / 0045825 A1. The component carrier comprises a cavity-forming base structure with a component carrier material, wherein a component is embedded in the cavity. The component carrier also comprises a first electrically insulating layer structure, which is connected to a front face of the base structure and the component and at least partially fills a gap between the component and the base structure. The component carrier further comprises a second electrically insulating layer structure, which is connected to the first electrically insulating layer structure at a connection surface of the first electrically insulating layer structure. The connection surface faces a counter surface of the second electrically insulating layer structure that is opposite the first electrically insulating layer structure.

[0009] The invention is based on the objective of providing a battery cell stack, a battery cell module and a method for manufacturing the battery cell module, which enables a fixed and electrically insulating connection of battery cells contained in the battery cell stack to a receptacle in a simple and cost-effective manner.

[0010] The problem is solved according to the invention by the features of the independent claims. Further practical embodiments and advantages of the invention are described in connection with the dependent claims.

[0011] A battery cell stack according to the invention comprises a plurality of battery cells arranged side by side, each battery cell having a prismatic cell housing with a connection surface. The cell housing can be attached to a receptacle by means of the connection surface. The cell housing of each battery cell is at least partially surrounded by an insulating film. In addition, an insulating layer, different from the insulating film, is arranged on at least one edge of the connection surface of each battery cell.

[0012] The prismatic cell housings can be substantially cuboidal in shape. The terminal sections of the battery cell are regularly formed on opposite end faces of the cuboid cell housing. The cell housing can additionally have a degassing opening, which is referred to in practice as a venting opening. In particular, the cuboid cell housing can have three different outer edge lengths. The connection surface can, for example, comprise the longest and the shortest outer edge lengths. A substantially cuboid cell housing with three different outer edge lengths, in which the connection surface comprises the longest and the shortest outer edge lengths, is referred to in this invention as a cassette-shaped cell housing.In the battery cell stack, the individual battery cells can be arranged side by side in such a way that the connection surfaces of the battery cells are located on a common side, for example, on a side designated as the underside when the battery cell stack is assembled in a motor vehicle. In this case, the largest surfaces of two adjacent battery cells with cassette-shaped cell housings face each other. These facing surfaces can be directly adjacent to each other or, preferably, spaced apart. For example, a thermal insulation material, a buffer material for compensating mechanical stresses, and / or a bonding layer can be arranged between the adjacent battery cells.

[0013] As mentioned above, an insulating layer, distinct from the insulating film, is arranged at at least one edge of the connection surface of each battery cell. In other words, at least the connection surface can be at least partially uncovered by the insulating film at at least one edge, and the insulating layer can be arranged at least partially on the cell housing at this section or sections. The insulating film and the insulating layer are arranged side by side on the cell housing of each battery cell and do not overlap. An edge of the connection surface can extend inwards from an outer edge of the connection surface by a few centimeters, preferably less than 5 cm. However, the edge can also be located at a small distance, particularly a distance of a few millimeters, from at least one adjacent edge of the battery cell housing.The term "at least one edge of the bonding surface" means that the insulating layer can be arranged at one, two, or more edges of the bonding surface. Preferably, the insulating layer can be arranged at two edges of the bonding surface.

[0014] Because the insulating film and the insulating layer differ from each other, they can be selected to meet locally specific, varying insulation requirements for the battery cells. Both the insulating film and the insulating layer are electrically insulating, so that in the battery cell stack described here, each battery cell is electrically insulated against unwanted current flow to the outside.

[0015] The insulating film and the insulating layer can differ, for example, in that the insulating film achieves a good compromise between electrical insulation and processability, whereas the insulating layer achieves a good compromise between electrical insulation and adhesion to a substrate. The insulating film and the insulating layer can also differ, in particular, in their strength and, preferably, in their shear strength. Advantageously, the insulating film has a shear strength of 0.5 MPa to 1.5 MPa. The insulating layer can advantageously have a shear strength of 5 MPa to 10 MPa and, more preferably, 6 MPa to 8 MPa.Additionally or alternatively, it is also possible that the insulating film and the insulating layer differ from each other in terms of their processing possibilities and / or their costs.

[0016] The insulating layer can either cover the entire edge of at least one cell. Alternatively, the insulating layer can cover at least one edge partially, particularly in sections. In the sections of the edge where the insulating layer is not provided, an insulating film or another electrically insulating material is preferably used. With the aforementioned sectional covering of the edge, it is advantageously possible, in a state where the battery cell stack is mounted in the battery cell module, to limit thermally induced stresses, to locally limit structural damage in the connection area, and / or to reduce material costs. In this way, high connection strength can be provided despite a potentially smaller connection area.

[0017] In a practical embodiment of the battery cell stack according to the invention, the battery cells can be arranged and the insulating layer configured such that the edges, together with the insulating layer, form at least one strip-shaped feature on a side of the battery cell stack having the connection surfaces. In other words, the insulating layers together form an elongated strip. For example, a rectangular section on one or more edges of the connection surface of each battery cell can be covered with the insulating layer. If several of the battery cells configured in this way, preferably cassette-shaped, are arranged side by side in the battery cell stack, the plurality of sections arranged side by side in series with the insulating layer form a strip. The portion of the connection surface not covered with the insulating layer can, in particular, be covered with the insulating film.In the aforementioned battery cell design, only a smaller portion of the contact surface is covered with the insulating layer than if the entire contact surface were covered. This simplifies and speeds up the application of the insulating layer. Furthermore, less of the often more expensive insulating layer material is required. The bond strength of the battery cells to a mounting remains high, particularly if the mounting's shape is adapted to the strip formed by the insulating layer. Against this background, the mounting—as also described in connection with the battery cell module—can advantageously be designed as a longitudinal beam, or at least have a section in the shape of a longitudinal beam, and the battery cell stack can be attached to the longitudinal beam by means of the strip formed by the insulating layer.In this combination, the insulating layer is applied precisely to the section of the connection surface where a connection to the longitudinal beam-shaped receptacle is intended or has already been achieved. The remaining surface sections of the battery cell housings can be covered with the insulating film, whose properties are not primarily geared towards connection to a receptacle, but rather towards high electrical insulation and ease of processing.

[0018] The strip formed by the insulating layer can be continuous along the side of the battery cell stack if the strips extend along the entire edge of at least one of the battery cells and the cells are arranged directly adjacent to one another. Alternatively, the strip can be interrupted, for example, if the strips do not extend along the entire edge of at least one of the battery cells but only partially at the connection surface. Similarly, the strip can be interrupted if the battery cells are additionally or alternatively spaced apart from one another.

[0019] In another practical embodiment of the battery cell stack, the insulating film and the insulating layer can differ in material and / or thickness. The insulating film can be made, for example, of polyethylene terephthalate, polyimide, polypropylene, polybutylene terephthalate, polyvinyl chloride, or polyphenylene sulfide. The insulating layer can be made, for example, of acrylic resin, polyurethane resin, epoxy resin, and / or silicone resin. In particular, the insulating layer can be a mixture of acrylic resin and polyurethane resin, a mixture of epoxy resin and acrylic resin, or a mixture of acrylic resin and silicone resin.

[0020] The insulating film can be, in particular, a foil. It is specifically not a coating. The insulating film can furthermore have a thickness of 0.01 mm to 1 mm, and more preferably 0.05 mm to 0.2 mm. The insulating layer can, in particular, be a coating, and more preferably a paint finish. The paint finish can, for example, be sprayed, poured, or brushed on. Alternatively, the insulating layer can also be an adhesive pad that is glued to the edge of the bonding surface. The insulating layer can, for example, have a thickness of 0.01 mm to 2 mm, and more preferably 0.2 mm to 0.5 mm.

[0021] It is possible for the battery cell stack to be directly attached to a receptacle via the insulating layer, or to be attached directly to it, provided the bond between the insulating layer and the receptacle provides sufficiently high strength. Preferably, however, an adhesive layer is additionally arranged on the side of the insulating layer facing away from the battery cell housing. This adhesive layer fixes the battery cells to the receptacle, enabling a particularly suitable combination of electrical insulation, insulating layer strength, and bond strength to the receptacle. The adhesive layer may, in particular, contain a UV-curable binder.

[0022] In another practical embodiment of the battery cell stack, the insulating layer can be arranged at two opposite edges of the connection surface of each battery cell. This is particularly advantageous because the battery cells can then be connected to two receptacles, thus achieving a higher connection strength of the battery cells to the receptacle and / or better distributing the forces and stresses acting on the connection. If the insulating layer is formed at two opposite edges of the connection surface, each of these edges can, in particular, have a strip-shaped form with the insulating layer as described above.

[0023] In yet another practical embodiment of the battery cell stack, each battery cell can have a degassing opening in its connection surface. This degassing opening allows the battery cells to release unwanted gases from the battery cell housing to the outside, thus preventing an undesirable pressure increase within the battery cell housing.

[0024] Integrating the degassing opening into the connection surface is particularly advantageous when the battery cell stack is arranged in a battery cell module intended for a motor vehicle. This is because, in a battery cell module installed in a motor vehicle, the connection side of the battery cell stack and its mounting can be located, in particular, on a side of the battery cell stack facing away from the passenger compartment. In the event of a crash, degassing from the battery cells then occurs not towards the passenger compartment, but away from it. In this context, it can be especially advantageous if the insulating layer is arranged at two opposite edges of the connection surface and the degassing opening is located in an area of ​​the connection surface situated between these edges.Because if a battery cell stack with these battery cells can be attached or connected to two spaced-apart, in particular longitudinal beam-shaped, mounts, the degassing opening of the battery cells can take place largely unhindered.

[0025] The invention also relates to a battery cell module comprising at least one battery cell stack according to the preceding description and at least one receptacle for the battery cell stack. The battery cells are fixed to the receptacle by means of the edge on which the insulating layer is arranged.

[0026] Regarding the battery cell module, reference is made to the above description of the battery cell stack, which is also applied to the battery cell module.

[0027] In another practical embodiment of the battery cell module, the battery cells can be fixed to the mounting by means of a material bond, in particular by means of an adhesive layer, at the at least one edge on which the insulating layer is arranged. Reference is made again in this regard to the adhesive layer described above in connection with the invention.

[0028] Additionally or alternatively, the at least one mounting can be designed as a longitudinal beam, in particular a T-beam, or at least have a section in the form of a longitudinal beam. By designing the mounting as a longitudinal beam, the battery cell module can be particularly robust yet lightweight. Preferably, the battery cell module can have two mountings designed as longitudinal beams, and the battery cell stack can have two of the strips formed by the insulating layer described above. Since the strips are formed on two opposite edges of the side of the battery cell stack containing the connection surfaces, the battery cell stack can be securely fixed to the mountings at these two edges. Any degassing opening provided in the battery cells can then be located, in particular, in an area situated between these edges.The longitudinal beams can be arranged in parallel. Additionally or alternatively, the longitudinal beam can be a component of a battery housing.

[0029] The battery cell module described above can be arranged, in particular, in a traction battery of a hybrid electric vehicle (HEV) or electric vehicle (EV). The invention therefore also relates to a traction battery with the battery cell module described above and to an HEV or EV with the battery cell module described above. In the HEV or EV, the connection surfaces of the battery cells and the at least one receptacle are provided on a side of the battery cell module facing away from the passenger compartment.

[0030] The invention also relates to a method for manufacturing the battery cell module described above, comprising the following steps: a) Providing at least one battery cell; b) Applying an insulating film to at least part of the cell casing of at least one of the battery cells; c) Applying an insulating layer to at least one edge of the connection surface of the at least one battery cell where the insulating film is not located; d) Fixing the at least one edge of the at least one battery cell, on which the insulating layer is arranged, to the at least one receptacle.

[0031] These manufacturing steps are carried out in the specified order. Within the manufacturing process, either individual battery cells can be processed sequentially in the specified order and then connected to the at least one holder, or a plurality of battery cells can be prepared and subjected to at least some of the manufacturing steps simultaneously.

[0032] Preferably, the battery cell stack described above is formed from a plurality of the battery cells – regardless of whether the battery cells were previously processed individually or together – before the edges are connected to the at least one receptacle, by arranging the battery cells side by side, in particular by pressing the battery cells together and / or electrically contacting them. However, it is also possible for the battery cell stack to be formed by fixing a plurality of the battery cells side by side to the at least one receptacle.

[0033] Applying the insulating film can, in particular, involve applying an insulating film, specifically a foil, to the cell casing. Applying the insulating layer can, in particular, involve spraying on a coating that hardens to form the insulating layer. For applying the insulating layer, it may be possible to first mask individual areas of the battery cell (e.g., the terminal sections and / or the vent) with a masking material that can be removed later, and then remove the masking material after the insulating layer has been applied.

[0034] Additionally or alternatively, fixing the edges to the at least one mount can include applying an adhesive layer to the insulating layer. In this case, the battery cells are fixed to the at least one mount by means of the adhesive layer. If the insulating layer and / or the adhesive layer contains a component that cures upon irradiation with UV light, the process can optionally include an additional step in which the insulating layer and / or the adhesive layer is cured with UV light. Regarding the manufacturing process, reference is also made to the descriptions concerning the battery cell stack and the battery cell module, which apply analogously to the manufacturing process.

[0035] As mentioned previously, in a practical embodiment of the manufacturing process, a plurality of the provided battery cells can be combined to form a battery cell stack. This combination can be performed, in particular, before the application of the insulating layer. In this case, the application of the insulating layer to the combined battery cells is carried out simultaneously. Furthermore, the battery cells combined to form the battery cell stack are simultaneously fixed to the at least one fixture. Alternatively, the plurality of the provided battery cells can be combined to form the battery cell stack described above before the edges of the battery cells are fixed to the at least one fixture.In this case, the step of applying the insulating layer to the individual battery cells is carried out separately, and the step of fixing the battery cells grouped together to form the battery cell stack to the at least one holder is carried out simultaneously.

[0036] In another practical embodiment of the manufacturing process, the insulating film can be applied to a portion of the connection surface of the at least one battery cell, leaving at least one edge of the connection surface untouched. This allows the insulating layer to be subsequently positioned at the edge particularly easily and quickly.

[0037] Further practical embodiments of the invention are described below in connection with the drawings. They show: Fig. 1 a battery cell of the battery cell stack according to the invention in a view from an oblique angle above; Fig. 2 the battery cell from Fig. 1 in a view from a low angle; Fig. 3 a battery cell stack according to the invention in a view from below; Fig. 4 a battery cell module according to the invention, comprising the battery cell stack made of Fig. 3 in a view from below; Fig. 5 a schematic representation of the inventive method for manufacturing the battery cell module according to a first embodiment; Fig. 6 a schematic representation of the inventive method for manufacturing the battery cell module according to a second embodiment.

[0038] In the Fig. Reference symbols 1 to 6, found in different figures, denote identical or functionally equivalent technical elements or process steps. For clarity, not all reference symbols are shown in the figures, although the elements may still be present.

[0039] The Fig. 1 and Fig. Figure 2 shows a possible embodiment of a battery cell 12 intended for use in a battery cell stack 10 according to the invention, in different views. The battery cell 12 has a prismatic cell housing 14. The cell housing 14 is cuboid in shape and comprises three different outer edge lengths. On the side of the cell housing 14 that has the shortest and longest edge lengths, the cell housing 14 includes a connection surface 16 with which the cell housing 14 can be connected to Fig. The cell housing 14 can be attached as shown in the 4 images 18, 18'. The cell housing 14 thus has a cassette-shaped form, whereby several battery cells 12 with the cassette-shaped cell housing 14 can be arranged upright in a battery cell stack 10 and with the connection surfaces 16 lying on a common side. For example, in an assembly state in a motor vehicle, the battery cells 12 can be arranged with the connection surface 16 facing away from the passenger compartment and, in particular, downwards.

[0040] An elongated degassing opening 20 is provided in the connection surface 16 of the cell housing 14, through which the interior of the cell housing 14 can be connected to its surroundings. When the degassing opening 20 is open, fluid can escape from the interior of the cell housing 14 into the surroundings, for example, if the internal pressure in the cell housing 14 increases in an accident involving a vehicle containing the battery cell 10. A terminal section 22, 22' is formed on each of the end faces of the cassette-shaped cell housing 14, which comprise the shortest and middle edges, respectively, and with which the battery cell 12 can be electrically connected.

[0041] The cell housing 14 is partially surrounded by an insulating film 24. Only on the end faces with the pole sections 22, 22' and on two opposing edges 26, 26' of the connection surface 16 is there no insulating film 24. The insulating film 24, which is formed as a foil, is made, for example, of polyethylene terephthalate and has a thickness of 0.1 mm. The edges 26, 26', where no insulating film 24 is provided, extend along the edge with the shortest outer edge length of the cassette-shaped cell housing 14. In this case, they project approximately 5 cm from the outer edge into the connection surface 16. The edges 26, 26' are completely covered with an insulating layer 28, 28', which is formed, for example, from sprayed and cured acrylic resin and thus differs from the insulating film 24 in terms of processing and material.The thickness of the insulating layer is 0.2 mm in this case. In an alternative embodiment of the battery cell, not shown, it is possible that the edges are formed on different outer edges than described above and / or that the edges are not continuously covered with the insulating layer along the edges, but only in sections, for example with a dashed pattern like a zebra stripe.

[0042] In Fig. Figure 3 shows a possible embodiment of a battery cell stack 10 according to the invention. The battery cell stack 10 comprises a plurality of the battery cells 12 described above, arranged side by side, so that the description of the battery cell can also be applied to the battery cells 12 contained in the battery cell stack 10.

[0043] In particular, the following are in Fig. In the battery cell stack 10 shown in Figure 3, thirty-two battery cells 12 are arranged side by side. The largest surfaces of the cassette-shaped cell housings 14 of two adjacent battery cells 12 face each other, so that the battery cells 12 stand upright. The connection surfaces 16 of the battery cells 12 are arranged on a common side of the battery cell stack 10, as already mentioned in the description of the battery cells 12. On this side of the battery cell stack 10, the connection surfaces 16 of the battery cells 12 can be connected by two Fig. The four images shown can be linked. Fig. Figure 3 is the common side of the battery cell stack 10 with the connecting surfaces 16, and the underside of the battery cell stack 10 is shown. The illustration shows that the edges 26, 26' of the battery cells 12, covered with the insulating layers 28, 28', form two straight strips along the battery cell stack 10 due to their adjacent arrangement. The two strips have breaks because the individual battery cells 12 are not in direct contact with each other, but rather a thin buffer material 30 is arranged between the corresponding surfaces of the battery cell housings 14 to compensate for mechanical stresses.

[0044] The battery cells 16 are located in the battery cell stack 10 at the in Fig. The three pole sections 22, 22' (not shown) are electrically connected to each other by means of contact elements 32, 32'. The contact elements 32, 32' can also provide a structural connection between the battery cells 16. The buffer material 30 and the contact elements 32, 32' can be advantageous for the formation of the battery cell stack 10, but they are not essential. They can, for example, also be provided as separate elements in a battery cell module.

[0045] In Fig. Figure 4 shows a possible embodiment of a battery cell module 34 according to the invention. The battery cell module 34 comprises the battery cell stack 10 described above, so that the description of the battery cell stack can also be applied to the battery cell module 12. The battery cell module 34 further comprises the two receptacles 18, 18', which in this case are each designed as a longitudinal beam and arranged parallel to each other. In an alternative embodiment not shown, the receptacles can also be designed as longitudinal beam-shaped sections, for example, of a battery housing. The battery cells 12 are fixed to each of the receptacles 18, 18' by means of the edge 26, 26' on which the insulating layer 28, 28' is arranged.Fixation is achieved by applying an additional adhesive layer (not shown) to the insulating layer 28, 28' and arranging the battery cells 12 with the adhesive layer on the receptacles 18, 18' before the adhesive layer hardens and thus creates a material-bonded fixation.

[0046] In one assembly state of the battery cell module 34, the battery cells 12 are arranged upright on the mounts 18, 18'. In one assembly state in a motor vehicle, the mounts 18, 18' and the connection surfaces 16 with the degassing openings 20 are then arranged on a side of the battery cell module 34 facing away from the passenger compartment.

[0047] Due to the connection of the battery cells 12 to the edges 26, 26', which have insulating layers 28, 28', on the receptacles 18' 18', the connection of the battery cells 12 exhibits a particularly advantageous combination of properties. Because of the selected material and / or thickness for the insulating layers 28, 28', the battery cells 12 are electrically insulated at the connection surfaces 16. Furthermore, the insulating layers 28, 28' and the connections of the insulating layers 28, 28' to the cell housing 14 exhibit higher shear strengths than the insulating film 24 or the connection of the insulating film 24 to the cell housing 14. The connection is therefore electrically insulating and particularly strong. It is also cost-effective, since the insulating layers 28, 28' are only applied to those areas of the connection surface that provide fixation to the receptacles 18, 18'.Furthermore, the degassing openings 20 provided in the connection surface 16 can freely abut a cavity due to the spaced arrangement of the receptacles 18, 18' relative to each other. In the event that degassing of the battery cells 16 is required, this occurs unimpeded.

[0048] The Fig. 5 and Fig. Figure 6 each shows an embodiment of the inventive method for manufacturing the battery cell module. The methods differ exclusively in the sequence of the process steps, so that the Fig. 6 second embodiment shown only with reference to the differences to the one in Fig. The embodiment shown in Figure 5 is described. Regarding the individual features described in the process steps, reference is also made to the preceding description.

[0049] At the in Fig. In the process described schematically in Figure 5, at least one battery cell is first provided. An insulating film is then applied to at least a portion of the cell housing of the at least one battery cell. During the application of the insulating film, the end faces of the battery cell housing and at least one edge of the connection surface remain unaffected by the insulating film. Preferably, two opposing edges of the connection surface remain unaffected by the insulating film, as described above. Alternatively, it is also possible to apply the insulating film to the end faces and / or edges and subsequently remove it. In a further process step, an insulating layer is applied to the exposed edges of the connection surface of the at least one battery cell where the insulating film is not located. Optionally, an adhesive layer is then applied to the insulating layer.The adhesive layer can also be omitted, in which case the battery cell is later fixed directly to the mount with the insulating layer.

[0050] The aforementioned process steps can be carried out sequentially for individual battery cells in the specified order. Alternatively, a majority of the battery cells can be prepared, and the process steps are performed with the majority of them. Regardless of whether the battery cells were processed individually or together, they are then assembled into a battery cell stack in a further process step, i.e., they are arranged side by side. During this process, the battery cells can also be electrically contacted and / or structurally connected to one another. Finally, the battery cell stack is fixed to a fixture by securing the battery cells to the fixture with their edges, which contain the insulating and adhesive layers.

[0051] The in Fig. The 6 schematically depicted procedures differ from the one in Fig.The method described in Figure 5 is further enhanced by combining the majority of the provided battery cells into a battery cell stack at the beginning of the process, particularly after applying the insulating film to the provided battery cells, and then subjecting the battery cells combined in the battery cell stack to the subsequent process steps together. In particular, the insulating layers are applied to the combined battery cells simultaneously, preferably such that the insulating layers form two strips along the bonding surface.

[0052] The features of the invention disclosed in the present description, the drawings, and the claims can be essential for realizing the invention in its various embodiments, both individually and in any combination. The invention can be varied within the scope of the claims and taking into account the knowledge of the person skilled in the art. Reference symbol list 10 battery cell stacks 12 battery cells 14 cell casings 16 connection area 18, 18' recording 20 Degassing opening 22, 22' Polar section 24 Insulation film 26, 26' edge 28, 28' Insulation layer 30 Buffer material 32 contact elements 34 battery cell module QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] DE 10 2021 131 034 A1

[0006] WO 2023 / 216033

[0007] US 2020 / 0045825 A1

[0008]

Claims

[1] Battery cell stack (10) comprising a plurality of battery cells (12) arranged side by side, wherein each of the battery cells (12) has a prismatic cell housing (14) with a connection surface (16) by means of which the cell housing (14) can be attached to at least one receptacle (18, 18'), and wherein the cell housing (14) of each of the battery cells (12) is at least partially surrounded by an insulating film (24), characterized by , that at least at one edge (26, 26') of the connection surface (16) of each of the battery cells (12) an insulating layer (28, 28') is arranged which differs from the insulating film (24). [2] Battery cell stack (10) according to claim 1, characterized by, that the battery cells (12) are arranged and the insulating layer (28, 28') are designed such that the edges (26, 26') together with the insulating layer (28, 28') form at least a strip-shaped shape on a side of the battery cell stack (10) having the connecting surfaces (16). [3] Battery cell stack (10) according to one of claims 1 or 2, characterized by , that the insulating film (24) and the insulating layer (28, 28') differ in terms of material and / or thickness. [4] Battery cell stack (10) according to any one of the preceding claims, characterized by , that the insulating layer (28, 28') is arranged at two opposite edges (26, 26') of the connection surface (16) of each of the battery cells (12). [5] Battery cell stack (10) according to any one of the preceding claims, characterized by that each of the battery cells (12) has a degassing opening (20) in the connection area (16). [6] Battery cell module (34) comprising at least one battery cell stack (10) according to one of the preceding claims and at least one receptacle (18, 18') for the battery cell stack (10), characterized by , that the battery cells (12) are fixed to the receptacle (18, 18') with the edge (26, 26') on which the insulating layer (28, 28') is arranged. [7] Battery cell module (34) according to the preceding claim, characterized by , that the battery cells (12) are fixed to the receptacle (18, 18') by means of a material bond, in particular by means of an adhesive layer, with the at least one edge (26, 26') on which the insulating layer (28, 28') is arranged, and / or that the at least one receptacle (18, 18') is designed as a longitudinal beam or has at least one section in the form of a longitudinal beam. [8] Method for manufacturing a battery cell module (34) according to one of the two preceding claims, comprising the following steps: a) Providing at least one battery cell; b) Applying an insulating film to at least part of the cell casing of at least one of the battery cells; c) Applying an insulating layer to at least one edge of the connection surface of the at least one battery cell, where the insulating film is not located; d) Fixing the at least one edge of the at least one battery cell, on which the insulating layer is arranged, to the at least one receptacle. [9] Method according to the preceding claim, characterized by, that a plurality of the provided battery cells are combined into a battery cell stack according to one of claims 1 to 5 before the application of the insulating layer or before fixing the edges of the battery cells to the at least one receptacle. [10] Method according to one of the two preceding claims, characterized by , that the insulating film is applied to a part of the connection surface of the at least one battery cell, leaving at least one edge of the connection surface untouched.

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