Battery cell complex for a vehicle battery and method for position detection of battery cells of a battery cell complex

Abstract

The invention relates to a battery cell complex (10) for a vehicle battery of a motor vehicle, comprising a plurality of battery cells (14) arranged side by side in a plane, and comprising at least one detection element (16) which is attached to a base (18) or a cover of one of the battery cells (14) and projects in axial direction (A) beyond this battery cell (14).

Description

[0001] The invention relates to a battery cell complex for a vehicle battery and a method for position detection of battery cells of a battery cell complex.

[0002] DE 10 2023 001 420 A1 describes a battery module for a motor vehicle. In this module, at least one element, designed as a bursting element, can be applied to a plurality of battery cells. Furthermore, the element is designed as an insulating element to thermally insulate at least a second battery cell from a venting gas in the event of overheating of a first battery cell.

[0003] US Patent 2010 / 0151314A1 describes a holding system for electrochemical storage cells, wherein each storage cell comprises a container with a bottom section and an upper section equipped with electrical output terminals. The holding system includes a first support element with through-holes and a plurality of adapter cups. Each adapter cup is designed to be placed on the upper section of a storage cell and inserted into one of the through-holes of the first support element.

[0004] From WO 2024 / 213680 A1, a battery arrangement is known which comprises a battery cell with a cell housing. The battery arrangement includes at least two cell stacks arranged within the cell housing. Furthermore, the battery arrangement includes at least one buffer unit, wherein at least two cell stacks are spaced apart from each other by the buffer unit. The buffer unit has at least one wall, wherein the wall is thermally conductive, at least in some areas. The battery arrangement ensures that a predetermined position of the cell stacks within the cell housing can be maintained, that any increase in the volume of cell stacks within a cell housing can be compensated for, and that the cooling of the cell stacks can be improved.Poorly positioned or displaced cell stacks can block the supply lines to rupture membranes, making it difficult or impossible to vent gaseous components in the event of overpressure.

[0005] The object of the present invention is to provide a solution which enables simple, precise detection of the position of battery cells in a foamed battery cell complex.

[0006] This problem is solved according to the invention by the subject matter of the independent claims. Further possible embodiments of the invention are disclosed in the dependent claims, the description, and the figures. Features, advantages, and possible embodiments set forth in the description for one of the subject matter of the independent claims are to be regarded, at least analogously, as features, advantages, and possible embodiments of the respective subject matter of the other independent claims, as well as of any possible combination of the subject matter of the independent claims, optionally in conjunction with one or more of the dependent claims.

[0007] The invention relates to a battery cell complex for a vehicle battery of a motor vehicle. The motor vehicle is, in particular, a car, especially a passenger car. The vehicle battery is, in particular, designed as a so-called high-voltage battery. The vehicle battery can serve as the traction battery of the motor vehicle and is thus configured to provide electrical energy for an electric drivetrain of the motor vehicle. The motor vehicle can therefore be electrically powered by means of electrical energy from the vehicle battery. The battery cell complex comprises a plurality of battery cells arranged side by side in a plane. The battery cells are, in particular, cylindrical cells or prismatic cells. The individual battery cells can, for example, be lithium-ion cells.Within the battery cell complex, the battery cells are fixed relative to one another. The battery cell complex further comprises at least one detection element, which is attached to the base or lid of one of the battery cells and projects beyond the battery cell in the direction in which the detection element is inserted. In other words, the detection element can be attached to the base of one of the battery cells and project axially beyond the base of that battery cell, or it can be attached to the lid of one of the battery cells and project axially beyond the lid of that battery cell. The axial direction runs parallel to a central axis of the battery cell, particularly in the case of a cylindrical battery cell configuration.

[0008] This detection element is designed to indicate the position of the battery cell marked by it, even when the battery cell complex is encased in foam. The detection element is designed to protrude sufficiently beyond the base of the battery cell that, when the battery cell complex is encased in foam, it is visible from the outside. This allows the position of the battery cell to which the detection element is attached to be determined. Based on the determined position of the battery cell marked by the detection element, the positions of other battery cells can be derived.Designing the battery cell complex with at least one detection element thus makes it possible to reliably determine the position of at least the battery cell marked by this detection element, in particular of all battery cells of the battery cell complex, within a foam block created by the foaming process, even after this battery cell complex has been foamed.

[0009] According to the invention, the detection element has at least one opening which extends completely through a wall of the detection element, particularly in the radial direction, and which is arranged at least partially free of overlap with the battery cell in a lateral direction perpendicular to the mounting direction in which the detection element is mounted onto the battery cell – the lateral direction being, in particular, the radial direction. This means that the opening is not covered by the battery cell, at least partially. If the detection element is attached to the bottom of the battery cell and the battery cell is oriented with its bottom facing downwards, then the opening is arranged at least partially below the bottom of the battery cell.If the detection element is attached to the bottom of the battery cell and the battery cell is oriented with its bottom facing upwards, then the opening is located at least partially above the bottom of the battery cell. Typically, the battery cells are oriented with their bottoms facing upwards for foaming, and a liquid foaming material is poured onto the respective bottoms of the battery cells from above. Foaming material that has entered the area circumferentially bounded by the support ring can flow out of this area through the at least one opening, particularly laterally. This effectively prevents the accumulation of foaming material in the area of ​​the detection element and, consequently, the risk of the detection element becoming over-foamed. In particular, the detection element is designed to have several openings distributed around its circumference.In particular, the openings are arranged at regular intervals around the circumference of the detection element.

[0010] In a possible further development of the invention, the detection element is designed in a ring shape and is concentric with a central axis of the battery cell, onto which the detection element is mounted. The ring shape of the detection element allows for a particularly simple coaxial arrangement of the detection element with respect to the cylindrical battery cell. If the detection element can thus be analyzed after the battery cell complex has been foamed, then the position of the central axis of this battery cell within the foamed battery cell complex can be determined from the central axis of the ring-shaped detection element.Furthermore, the ring-shaped design of the detection element enables particularly easy and safe attachment of the detection element to the battery cell, as well as particularly easy and precise concentric alignment of the detection element to the battery cell.

[0011] In a further possible embodiment of the invention, the detection element comprises a support ring radially enclosing the battery cell and at least one positioning tab projecting radially from the support ring towards a central axis of the detection element. This positioning tab rests against the bottom of the battery cell and defines the axial end position of the detection element relative to the battery cell. In other words, the detection element can be attached to the battery cell in the axial direction until the positioning tab abuts the bottom of the battery cell. The axial end position of the detection element relative to the battery cell is thus defined by the positioning tab abutting the bottom of the battery cell.By selecting the position of the positioning tab on the detection element, it is possible to determine how far the detection element projects axially beyond the base of the battery cell. The positioning tab allows axial displacement of the detection element relative to the battery cell to be limited, and in particular prevented, at least in one direction along the axial axis. Specifically, several positioning tabs can be provided on the detection element, each arranged on the support ring and projecting radially towards the central axis of the detection element. It is specifically provided that all positioning tabs are arranged at regular intervals around the circumference of each other on the support ring. Furthermore, it is specifically provided that all positioning tabs are arranged at the same height in the axial direction.The positioning tabs ensure that the detection element can be easily and precisely positioned in the predetermined final position axially to the battery cell. Furthermore, the positioning tabs, which rest against the base of the battery cell, minimize the risk of the detection element tilting relative to the battery cell. This reliably enables precise concentric alignment of the detection element with the battery cell.

[0012] In a further possible embodiment of the invention, the detection element is provided with a marking surface at its free end, particularly in the axial direction. This marking surface is designed to prevent the foaming material from being covered during the foaming process. The marking surface can be colored differently from the foaming material. This allows the marking surface to be detected particularly easily after the battery cell complex has been foamed, thereby enabling the position of the battery cell marked by the detection element to be determined particularly easily based on the detected marking surface.

[0013] In this context, it is particularly intended that the detection element is closed at its free end by an annular marking surface, especially in the axial direction. This annular marking surface is designed to prevent it from being covered by the foaming material during the foaming process. The annular marking surface is arranged concentrically to the central axis of the battery cell, which allows the position of the battery cell marked by the detection element to be determined particularly easily and precisely based on the position of the marking surface within the foam body.

[0014] In a further possible embodiment of the invention, the detection element is designed to be elastic and / or resilient, at least in certain areas. For example, the detection element is a multi-component component with at least one elastic / resilient element.

[0015] The detection element may be made of an elastomer. Elastomers are dimensionally stable but elastically deformable plastics whose glass transition temperature is below room temperature. Elastomers can deform under tensile and compressive stress but subsequently return to their original, undeformed shape. Specifically, it is envisaged that during the foaming of the battery cell complex, the battery cells are oriented with their bases facing upwards, the foaming material is applied to the bases of the battery cells from above, and then a mold cover is brought close to the battery cells from above. This mold cover limits how far the foaming material can expand during foaming. By designing the detection element from the elastomer, it can be ensured that, as the mold cover approaches the battery cell complex, it presses against the detection element.Furthermore, the design of the elastomer detection element allows it to – if necessary, by slightly deforming the element – ​​to fully conform to the mold lid with its circular marking surface. Consequently, the direct contact of the circular marking surface with the mold lid prevents the marking surface from being covered by the foaming material. After foaming, the mold lid is removed from the battery cell complex, and the circular marking surface can be seen within the resulting foam body. Additionally, the design of the elastomer detection element prevents mechanical stresses from being introduced into the battery cell to which the detection element is attached, as a result of the contact between the mold lid and the detection element.This significantly reduces the risk of damage to the battery cell marked by the detection element.

[0016] In a further possible embodiment of the invention, the detection element is arranged on a battery cell that forms a corner of the battery cell complex. In particular, all battery cells of the battery cell complex form a substantially rectangular shape in the cross-section of the battery cell complex, with the battery cell marked by the detection element forming a corner of this rectangular shape. Thus, the position of further battery cells of the battery cell complex can be determined particularly easily based on the detected position of the detection element in the foam body formed after the battery cell complex has been foamed, since it is known that the detection element marks a battery cell that forms a corner of the battery cell complex.

[0017] In a further possible embodiment of the invention, the battery cell complex is designed in a cuboid shape, consisting of single-layered battery cells arranged side by side. A detection element is attached to each battery cell, which forms one corner of the rectangular cross-section of the battery cell complex. The rectangular cross-section of the battery cell complex is perpendicular to the axial direction of the battery cells. Thus, the battery cell complex is designed so that the four detection elements mark the battery cells that form the respective corners of the rectangular cross-section. Based on the respective detected positions of the detection elements in the foam body formed after the battery cell complex has been foamed, the positions of all other battery cells in the battery cell complex can then be determined particularly easily and reliably.

[0018] The invention further relates to a method for position detection of battery cells of a battery cell complex for a vehicle battery of a motor vehicle. In the method, at least one detection element is attached to a base or a cover of a battery cell, whereby the detection element projects beyond the battery cell in the direction in which it is attached. It is possible for the detection element to be attached to the battery cell in the axial direction. As a result of this attachment, the detection element can circumferentially encircle the battery cell along an axial length. In particular, it is provided that by attaching the at least one detection element to the battery cell, a battery cell complex is formed, as already described in connection with the battery cell complex according to the invention.The method further provides for the detection of the relative position of all battery cells in the battery cell complex to the detection element. This detection can be performed, for example, by a camera system that records at least one image depicting the battery cell complex and then evaluates this image. The evaluation of the at least one image can be performed using an image processing device. The at least one detection element can be attached to the battery cell by a person or by an industrial robot.

[0019] In this method, after attaching at least one detection element to the base of the battery cell and detecting the relative position of all battery cells in the battery cell complex to the detection element, the battery cell complex is foamed. For this foaming process, a foaming material can be applied to the battery cells, particularly to the bases of all battery cells and into the spaces between the battery cells. For this purpose, the battery cells can be aligned with their respective bases facing upwards in a foaming tool. The foaming tool can have a tool cover that can be moved towards the bases of the battery cells. The tool cover can be used to define the shape of the foam body to be produced by foaming the battery cell complex.Furthermore, the tool lid is positioned against the at least one detection element before or during the foaming process, particularly against its marking surface, to ensure that at least a portion of the detection element, especially the marking surface, remains free of the foaming material. The method also includes determining the position of the at least one detection element within the foam body created by the foaming process. This position can be determined using a camera device. For this purpose, the camera device can record at least one image depicting the foam body. This image can then be evaluated using an image processing device.In particular, the position of the at least one detection element can be determined based on a color difference between the at least one detection element, especially its marking surface, and the foam.

[0020] In a further possible embodiment of the invention, a first detection element is attached to a first battery cell before foaming, a second detection element is attached to a second battery cell before foaming, a third detection element is attached to a third battery cell before foaming, and after foaming, the position of all battery cells within the foam body is additionally determined as a function of a relative change in the position of the detection elements from a first time point before foaming to a time point after foaming. As a result of the penetration of foam material into the spaces between the battery cells, the position of the battery cells relative to each other within the battery cell complex can change as a result of the foaming process.By comparing the position of at least three detection elements, in particular the position of four detection elements, which are arranged at respective corners of the rectangular cross-section of the battery cell complex in a plane perpendicular to the axial direction of the battery cells, before foaming with their position relative to each other after foaming, it is possible to determine the average distance the battery cells of the battery cell complex have moved from their respective neighboring battery cells as a result of the foaming process. Based on this information, and taking into account the respective absolute positions of the detection elements within the foam body, the position of all battery cells of the battery cell complex within the foam body can then be determined with particular precision.

[0021] Further features of the invention may become apparent from the claims, the figures, and the description of the figures. The features and combinations of features mentioned above in the description, as well as the features and combinations of features shown below in the description of the figures and / or in the figures themselves, can be used not only in the combinations specified, but also in other combinations or individually, without departing from the scope of the invention.

[0022] The drawing shows in: Fig. 1 a schematic perspective view of a section of a battery cell complex arranged on a carrier of a vehicle battery; Fig. 2 a schematic perspective view of a battery cell on which a detection element is attached; and Fig. 3a to 3d show the detection element in different views.

[0023] In the figures, identical and functionally equivalent elements are provided with the same reference symbols.

[0024] In Fig. Figure 1 shows a partial schematic perspective view of a battery cell complex 10, which is arranged on a carrier 12 of a vehicle battery of a motor vehicle. The battery cell complex 10 comprises a plurality of battery cells 14, which are designed as cylindrical cells. The battery cells 14 are arranged side by side in the battery cell complex 10 in a plane perpendicular to an axial direction A of the respective battery cells 14. For the sake of clarity, only some of the battery cells 14 are labeled with the corresponding reference numeral. The battery cells 14 of the battery cell complex 10 are arranged such that the battery cell complex 10 has at least substantially the shape of a rectangle in a plane perpendicular to the axial direction A of the battery cells 14.Furthermore, it is provided that the battery cell complex 10 comprises at least one detection element 16. In the present case, the battery cell complex 10 comprises four detection elements 16. Each detection element 16 is attached to a base 18 of an associated battery cell 14 by being plugged onto this battery cell 14. In the case of . Fig. In the illustration shown, all battery cells 14 are depicted with their base 18 facing upwards. The respective detection elements 16 are designed to mark the individual battery cells 14 located at the respective corners of the rectangular cross-section of the battery cell complex 10. In other words, the respective corners of the battery cell complex 10 are marked by means of the respective detection elements 16.

[0025] In Fig. Figure 2 shows a single battery cell 14 in a perspective view, with the detection element 16 attached to this battery cell 14. It can be seen that the detection element 16 projects in axial direction A beyond the base 18 of the battery cell 14. The detection element 16 is in the Fig. Sections 3a to 3d are shown separately in different views. Detection element 16 is shown in... Fig. 3a shown in an isometric view, in Fig. 3b in a side view, in Fig. 3c in a top view and in Fig. 3D model shown in a top view from below. In the Fig. In the isometric view shown in 3a, the detection element 16 is shown from a low angle. The following section describes how... Fig. Sections 3a to 3d describe the structure of the detection element 16 in more detail. The detection element 16 is made of an elastomer and is designed to be ring-shaped. It comprises a support ring 20, which is designed to circumferentially enclose the battery cell 14, onto which the detection element 16 is mounted, along an axial length. The support ring 20 allows the detection element 16 to be mounted onto the battery cell 14 particularly easily and precisely in a concentric position. In this concentric alignment, the central axis of the detection element 16 coincides with the central axis of the battery cell 14, which extends in the axial direction A. As described in the Fig. To ensure that the detection element 16 can still be recognized as described in sections 3a to 3d, it is provided that the detection element 16 has several positioning tabs 22 which project radially from the carrier ring 20 towards the central axis of the detection element 16. These positioning tabs 22 are arranged evenly distributed around the circumference of the carrier ring 20. The positioning tabs 22 are designed to be pressed against the base 18 of the battery cell 14, onto which the detection element 16 is mounted, thereby defining an axial end position of the detection element 16 relative to the battery cell 14.

[0026] As further in the Fig. To ensure that the detection elements 3a to 3d can be detected particularly well, the detection element 16 is provided to have several openings 24 which extend radially through a wall of the detection element 16. The radial direction is perpendicular to the longitudinal direction of the central axis of the detection element 16. The respective openings 24 are arranged uniformly around the circumference of the detection element 16. As shown in Fig.To ensure that the detection element 16 can be detected particularly well, the respective openings 24 are arranged on the detection element 16 such that, when the detection element 16 is attached to the associated battery cell 14, the openings 24 are arranged at least partially without overlapping the battery cell 14 in the radial direction. In other words, the openings 24 are arranged at least partially on the side of the base 18 of the battery cell 14 facing away from the base body of the battery cell 14. Furthermore, the detection element 16 has an annular marking surface 26 at its free end, which closes off the detection element 16 axially to the outside at its free end.

[0027] The detection elements 16 are used for position detection of the battery cells 14 of the battery cell complex 10, as described below. Four detection elements 16 are attached to the respective bases 18 of the battery cells 14 to be marked by these detection elements 16, so that the detection elements 16 project axially A beyond the respective bases 18 of these battery cells 14. The relative position of all battery cells 14 of the battery cell complex 10 to the detection elements 16 is then detected. Following this, the battery cell complex 10 is foamed by applying a foaming material to the battery cells 14, which are oriented with their respective bases 18 facing upwards.The design of the detection elements 16 with their respective openings 24 ensures that no foam pool forms on the bases 18 of the marked battery cells 14 in the area of ​​the respective detection elements 16, but rather that the foaming material can flow laterally, at least partially, through the openings 24 and away from the bases 18 of the marked battery cells 14. Before or during the foaming process, a tool cover can be moved axially towards the bases 18 of the battery cells 14. The tool cover limits the extent to which the foaming material can expand during foaming. In particular, the tool cover is moved axially so close to the battery cells 14 that the detection elements 16, with their respective marking surfaces 26, are in contact with the tool cover. After the foam has at least partially hardened, the tool cover is removed from the battery cell assembly 10.Within the framework of this process, the position of the respective detection elements 16 within the foam body created by the foaming process can then be detected. Because the tool lid rested against the marking surfaces 26 of the detection elements 16, at least during the foaming process, these marking surfaces 26 are flush with an outer surface of the foam body and are therefore visible from the outside. The positions of all battery cells 14 within the foam body can be determined based on the determined positions of the detection elements 16 within the foam body and the relative position of the respective battery cells 14 to the detection element 16, which was determined before the battery cells 14 were foamed.It is possible that when determining the positions of all battery cells 14, a positional shift of the detection elements 16 from a time before foaming to a time after foaming is included.

[0028] The described invention is based on the understanding that, due to over-foaming of the battery cells 14, the position of each individual battery cell 14 can no longer be reliably detected without detection elements 16. The need to detect the positions of the battery cells 14 after the foaming process arises from the requirement to ensure that the respective cell vents – which are pressure relief valves of the battery cells 14 – located at the base 18 of each battery cell 14, are aligned with the respective degassing channels of the vehicle battery. The respective detection elements 16 are additional components on individual battery cells 14 that can be detected after the foaming process.The detection elements 16, designed as elastomer rings, are such that they are visible after the foaming process and can be detected by means of a camera. Based on the determined position of each detection element 16, the position of the battery cell 14 marked by this detection element 16 can be precisely determined.

[0029] Overall, the invention shows how an injection-molded elastomer element - and thus the detection element 16 - can be used for cell position detection. Reference symbol list 10 battery cell complex 12 carriers 14 battery cells 16 Detection element 18 Floor 20 carrier rings 22 Positioning tab 24-hour opening 26 marking area A axial direction

Claims

[1] Battery cell complex (10) for a vehicle battery of a motor vehicle, comprising a plurality of battery cells (14) arranged side by side in a plane, and comprising at least one detection element (16) which is attached to a base (18) or a cover of one of the battery cells (14) and projects beyond the battery cell (14) in the direction in which the detection element (16) is placed on the battery cell (14), characterized by , that the detection element (16) has at least one opening (24) which extends completely through a wall of the detection element (16) and which is arranged in a lateral direction perpendicular to a mounting direction in which the detection element (16) is mounted on the battery cell (14) at least partially without overlap with the battery cell (14). [2] Battery cell complex (10) according to claim 1, characterized by, that the detection element (16) is designed in a ring shape and is aligned concentrically to a central axis of the battery cell (14) onto which the detection element (16) is mounted. [3] Battery cell complex (10) according to claim 1 or 2, characterized by , that the detection element (16) has a support ring (20) radially enclosing the battery cell (14) and at least one positioning tab (22) projecting radially from the support ring (20) towards a central axis of the detection element (16), which rests against the bottom (18) or the lid of the battery cell (14) and defines an axial end position of the detection element (16) relative to the battery cell (14). [4] Battery cell complex (10) according to any one of the preceding claims, characterized by , that the detection element (16) is closed at its free end by a marking surface (26). [5] Battery cell complex (10) according to claim 4, characterized by, that the detection element (16) is closed at its free end by an annular marking surface (26). [6] Battery cell complex (10) according to any one of the preceding claims, characterized by , that the detection element (16) is designed to be elastic and / or resilient, at least in some areas. [7] Battery cell complex (10) according to any one of the preceding claims, characterized by , that the detection element (16) is arranged on a battery cell (14) which provides a corner of the battery cell complex (10). [8] Battery cell complex (10) according to any one of the preceding claims, characterized by , that the battery cell complex (10) is formed in a cuboid shape from single-layered battery cells (14) arranged next to each other and that a detection element (16) is attached to each battery cell (14), which provides one corner of the rectangular cross-section of the battery cell complex (10). [9] Method for position detection of battery cells (14) of a battery cell complex (10), comprising the steps: - Attaching at least one detection element (16) to a base (18) or a cover of a battery cell (14), whereby the detection element (16) protrudes beyond the battery cell (14) in the insertion direction of the detection element (16) onto the battery cell (14), - Detection of the relative position of all battery cells (14) of the battery cell complex (10) to the detection element (16), - Foaming of the battery cell complex (10), - Determining the position of at least one detection element (16) within the foam body created by foaming, - Determining the positions of all battery cells (14) within the foam body as a function of the determined position of the detection element (16) and the determined relative position of the respective battery cells (14) to the detection element (16). [10] Method according to claim 9, characterized by , that before foaming a first detection element (16) is attached to a first battery cell (14), before foaming a second detection element (16) is attached to a second battery cell (14), before foaming a third detection element (16) is attached to a third battery cell (14), and after foaming the position of all battery cells (14) within the foam body is additionally determined as a function of a relative change in the position of the detection elements (16) to each other from a first time before foaming to a second time after foaming.

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