Method for manufacturing a vehicle battery, vehicle battery and motor vehicle

Abstract

The present invention relates to a method for manufacturing a vehicle battery, wherein a plurality of battery cells are arranged side by side parallel to each other with their central axes (V1); each of the battery cells is electrically contacted on its end side by means of a cell contact system, thereby electrically connecting the battery cells to each other (V2); each battery cell is coated with an adhesive layer on its end side in contact with the cell contact system (V3); and each battery cell is foamed with foam at least in the region of its end side in contact with the cell contact system (V4).

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a vehicle battery, a vehicle battery for a motor vehicle, and a motor vehicle having a vehicle battery. Background Technology

[0002] A method for coating battery cells in a vehicle battery is known from DE102018128501A1. In this method, the battery cells are coated with an insulating varnish layer. The varnish layer is inspected using an inspection device. In connection with the inspection, an insulating film is adhered to the varnish layer, and stress is applied to the varnish layer in order to inspect it using the inspection device.

[0003] Additionally, an energy storage device for a motor vehicle is known from DE102019130435A1. The energy storage device includes an energy storage unit having a flame-retardant material and a sheath. The flame-retardant material may include a layered structure having a base layer (especially an adhesion promoter), a first foamed paint layer, a second foamed paint layer, and a top layer. Summary of the Invention

[0004] The objective of this invention is to provide a solution that allows for particularly reliable enclosed foaming of multiple battery cells in a vehicle battery.

[0005] The task described herein is solved by the subject matter of each independent claim. Further possible solutions to the invention are disclosed in the dependent claims, the description, and the drawings. Features, advantages, and possible solutions set forth within the scope of the description for one of the subjects of the independent claims can be at least similarly regarded as features, advantages, and possible solutions of the corresponding subjects of the other independent claims, and can at least similarly regarded as features, advantages, and possible solutions of any possible combination of the subjects of the independent claims (perhaps in combination with one or more dependent claims).

[0006] This invention relates to a method for manufacturing a vehicle battery intended for use in a motor vehicle. Specifically, the vehicle battery can be used in automobiles, particularly passenger cars. The vehicle battery is specifically configured to provide electrical energy for the electric drive system of the motor vehicle. Thus, the motor vehicle can be electrically driven by means of electrical energy from the vehicle battery. The vehicle battery can be, in particular, a so-called high-voltage battery. The method specifies that a plurality of battery cells are arranged side-by-side parallel to each other with their central axes. Here, the battery cells can be arranged side-by-side, for example, on a so-called cell carrier. In other words, a battery cell composite is formed by the plurality of battery cells, in which the battery cells are positioned relative to each other. The method further specifies that each of the battery cells is electrically contacted on its end side by means of a cell contact system, thus electrically connecting the battery cells to each other. The cell contact system can particularly include a plurality of cell connectors configured to directly connect corresponding two battery cells among the battery cells to each other, thus connecting the battery cells in series and / or in parallel via the cell contact system. Specifically, it is specified that at least one electrode of each individual battery cell is disposed on the same side of the battery cell assembly. Therefore, the cell contact system only needs to be attached to one side of the battery cell assembly to interconnect all the electrodes of each individual battery cell. When all the electrodes of each individual battery cell, and therefore not only the positive but also the negative electrodes, are disposed on the end sides of each individual battery cell and these end sides are disposed on the same side of the battery cell assembly, interconnection of the individual battery cells can be particularly simple. Therefore, the cell contact system can make electrical contact with all the individual battery cells particularly simple, and thus, the vehicle battery can be assembled particularly simply.

[0007] The method further specifies that each battery cell is coated with an adhesion promoter on its end side that contacts the cell contact system. Here, each battery cell is coated with an adhesion promoter at least partially on its end side that contacts the cell contact system. Alternatively, all battery cells are coated with an adhesion promoter on their end sides that contact the cell contact system. An adhesion promoter is understood as a substance that establishes a tight physical bond or, generally, a chemical bond at the boundary of immiscible materials. In some contexts, an adhesion promoter is also referred to as a primer. Adhesion promoters improve the adhesion of the adhesive and the coating to the substrate. The adhesion strength of the coating is defined as a measure of the resistance of the coating to mechanical separation from the substrate.

[0008] The method further specifies that each battery cell is surrounded by foam at least in the region on its end side that contacts the cell contact system. Therefore, the adhesion layer serves to reliably connect the foam to the battery cell. This connection can thus achieve a cohesive fracture pattern in the event of failure. Cohesive fracture is failure within the layer. In such fracture characteristics, the adhesion of the adhesion agent to the battery cell or to the foam is greater than the internal strength of the adhesion layer or the foam. In other words, the foam is held so firmly to the end side of the battery cell by means of the adhesion layer that, in the event of failure, fracture occurs in the adhesion layer and / or the foam, but the foam does not detach from the adhesion layer, or the adhesion layer does not detach from the battery cell. Therefore, the method allows the foam used to surround the battery cell to be held particularly reliably to the battery cell, especially to the end side of the battery cell.

[0009] In one possible extension of the invention, a varnish is specified as the adhesion layer. The varnish is a liquid or powder coating material that is thinly applied to an article and formed into a continuous solid film through a chemical or physical process. Applying an adhesion layer in the form of varnish allows for a particularly large and continuous coating of the respective end faces of the battery cell with the adhesion layer; therefore, the foam can be reliably retained at least on the end faces of the respective battery cell.

[0010] In this relationship, it can be specifically stipulated that the applied paint is cured by irradiation with ultraviolet light. Ultraviolet light refers to ultraviolet radiation with a wavelength range of 100 nm to 400 nm. Therefore, the paint is an ultraviolet-cured paint. Using an ultraviolet-cured paint allows the paint to be cured selectively and precisely by irradiation with ultraviolet light after application. This ensures reliable and uniform curing of the paint. Furthermore, the paint can be cured particularly quickly by irradiation with ultraviolet light.

[0011] In another possible embodiment of the invention, an electrically insulating material is used as the adhesion layer. Therefore, the adhesion layer is non-conductive and thus has only extremely small and therefore negligible conductivity. Consequently, current flow between the end face of the battery cell and other components of the vehicle battery can be particularly well prevented, bypassing the cell contact system. In particular, the risk of short circuits within the vehicle battery is thus kept particularly low. Therefore, the adhesion layer can fulfill the function of both an adhesion promoter and an electrically insulating material. Because so many functions can be achieved with the help of the adhesion layer, the vehicle battery can be constructed in a particularly compact and lightweight manner, as it eliminates the need for different components for different functions.

[0012] In another possible embodiment of the invention, circular cells are used as battery cells. These circular cells are at least substantially cylindrical, with the axial direction of the respective battery cell coinciding with the longitudinal extension direction of the respective battery cell's central axis. Each battery cell has two end sides, which are arranged on opposite sides of the battery cell with reference to the axial direction. In particular, it is specified that not only the positive terminal but also the negative terminal, and therefore not only the positive electrode but also the negative electrode, are arranged on the same end sides of the respective battery cells. Thus, the cell contact system is connected only to one end side of the respective battery cell to interconnect the individual battery cells. The circular cells can be, in particular, lithium-ion cells.

[0013] In this relationship, it can be specifically stipulated that the adsorption layer is coated on the end side of the corresponding battery cell at least in the region of the cell shoulder. The cell shoulder of the corresponding battery cell is located in the radial edge region of one end side of the battery cell, and the cell shoulder is immediately adjacent to the edge of the peripheral surface of the battery cell on that end side. Therefore, the cell shoulder is located in the region of the transition between the end side and the peripheral surface of the corresponding battery cell. By coating the adsorption layer at least in the region of the cell shoulder, particularly reliable adhesion of the foam to the cell shoulder of the corresponding battery cell can be achieved. Therefore, particularly reliable surrounding foaming of the corresponding battery cell can be achieved.

[0014] In this arrangement, it can be further stipulated that each battery cell has an electrically insulating film attached to its circumferential surface before they are arranged side-by-side. In other words, each battery cell is wrapped with an electrically insulating film on its circumferential surface and then arranged side-by-side parallel to each other along its central axis. The electrically insulating film allows for particularly reliable electrical insulation of each battery cell on its circumferential surface. After the battery cells are arranged in a battery cell assembly, where they can be arranged side-by-side with their circumferential surfaces touching each other, it is possible that the corresponding circumferential surfaces of each battery cell are no longer accessible, at least partially, for subsequent electrical insulation. Because the battery cells are electrically insulated on their circumferential surfaces before being arranged side-by-side, reliable electrical insulation of each battery cell on its circumferential surface can be guaranteed. The attachment of an electrically insulating film to each battery cell allows for particularly simple and rapid reliable electrical insulation of all battery cells across their entire circumferential surface. Electrical insulation of the individual cells on the end sides that will at least contact the cell contact system will not occur in this case, so that after the individual cells are arranged in the cell assembly, the individual cell connectors of the cell contact system can be connected to the respective end sides of the individual cells. If the individual cells are already electrically insulated on their end sides that will contact the cell contact system before being arranged in the cell assembly, then the electrical insulation on these end sides must be at least partially removed before connecting to the cell contact system to allow electrical connection with the cell contact system. When removing the electrical insulation on each end side to allow connection with the cell contact system, particles of the electrical insulation may be released during grinding or laser ablation, and these particles may then contaminate the cell assembly again. This contamination can be avoided in the method described herein by the fact that electrical insulation of the individual cells on their end sides that will connect to the cell contact system will not occur before the individual cells are arranged in the cell assembly and therefore before connecting to the cell contact system. After each battery cell is disposed in the battery cell composite and made electrically contact with the cell contact system, each battery cell can be electrically insulated at least partially by coating an adhesion layer on its end side, provided that the adhesion layer is also an electrically insulating coating.

[0015] In another possible embodiment of the invention, the adhesion layer is applied by means of a printhead. The adhesion layer is thus applied to the region of the end face of the respective battery cell by means of a non-spraying application method. Therefore, the adhesion layer is at least partially printed onto the respective end face of the battery cell. Thus, the region on the respective end face of each battery cell designated for coating can be provided with the adhesion layer with particular precision. For example, it is possible here that components of the cell contact system are exempt from being coated with the adhesion layer. The described method allows the adhesion layer to be coated with particularly clearly defined boundaries in predetermined areas of the battery cell.

[0016] The present invention also relates to a vehicle battery for motor vehicles, comprising a plurality of battery cells, particularly circular cells, arranged side-by-side parallel to each other with their central axes. The vehicle battery also includes a cell contact system, with each battery cell contacting the cell contact system on its respective end side, thus electrically connecting the battery cells to each other. Each battery cell is coated with an adhesion layer at least on its corresponding end side in contact with the cell contact system. Additionally, each battery cell is foamed with foam at least in the region of its end side in contact with the cell contact system. In particular, each battery cell is foamed with foam in the region where the adhesion layer is applied. This means that the foam is in direct contact with the adhesion layer and is held particularly reliably on the battery cell by the adhesion layer. In particular, the vehicle battery is manufactured within the scope of the method, as described in relation to the method for manufacturing a vehicle battery according to the invention.

[0017] The present invention also relates to a motor vehicle comprising a vehicle battery, as already described in the relation to a vehicle battery according to the invention. Motor vehicles are particularly automobiles, particularly passenger cars, or particularly motorized bicycles, such as motorcycles.

[0018] Other features of the invention can be obtained from the claims, the drawings, and the description taken in conjunction with the drawings. Features and combinations of features mentioned above in the specification, as well as features and combinations of features shown separately in the description taken in conjunction with the drawings and / or in the drawings, may be applied not only in the correspondingly described combinations, but also in other combinations, or may be applied separately, without departing from the scope of the invention. Attached Figure Description

[0019] The attached figure is the only one ( Figure 1 The diagram shows a simplified method for manufacturing vehicle batteries for motor vehicles. Detailed Implementation

[0020] The method includes method steps V1 to V4, which are performed sequentially as described. In the first method step V1, it is specified that a plurality of battery cells are arranged side-by-side parallel to each other along their central axes, and these battery cells are currently configured as circular cells. It may be specified that each battery cell has an electrical insulating film attached to at least its circumferential surface before they are arranged side-by-side.

[0021] In the second method step V2, each battery cell is electrically contacted on its end side by means of a cell contact system, thus electrically connecting the battery cells to each other. In the third method step V3, each battery cell is coated with an adhesion layer on its end side that contacts the cell contact system. Here, the adhesion layer is applied to the end side of the respective battery cell, at least in the area of ​​the cell shoulder. The adhesion layer is currently applied by means of a printhead. Currently, as the adhesion layer, a varnish is applied, which is then cured by ultraviolet light irradiation. The adhesion layer is currently additionally electrically insulating. In the fourth method step V4, each battery cell is foamed, at least on its end side that contacts the cell contact system.

[0022] The foaming of a cell assembly consisting of multiple battery cells allows heat transfer to be avoided and mechanical loads to be absorbed when the vehicle battery is used in a motor vehicle. Specifically, the cell assembly is surrounded by foam after it is arranged in the storage casing of the vehicle battery. The storage casing with the foamed and film-coated cell assembly can meet mechanical requirements as part of the vehicle body structure. Importantly, the foam provides a material-locked connection with at least a portion of the surface of each battery cell. To achieve this, the adhesion layer is selectively and therefore not comprehensively coated, at least on a portion of a specific surface within the vehicle battery. Currently, the adhesion layer is applied at least partially to the end side of each battery cell that contacts the cell contact system. Currently, each battery cell has an adhesion layer at least in the region of its respective cell shoulder to establish a material-locked connection between the cell casing of the respective battery cell and the foam surface of the foam. This connection is specified to have a cohesive fracture pattern in the event of failure. The adhesion layer is selectively applied because this coating is achieved during the assembly process of the vehicle battery, and the relevant surfaces or mounting parts can therefore remain uncoated. It can meet the high requirements for technical cleanliness during the assembly process.

[0023] The adhesion layer to be applied to the battery cells is currently composed of a UV-cured varnish. This varnish functions as an adhesion bridge between the battery cell surface and the foam body, thus allowing for particularly good transfer of mechanical loads between the foam and the battery cell. The UV varnish can additionally provide electrical insulation, which is only necessary in selected areas of the vehicle battery, eliminating the need for extensive coating.

[0024] Selective coating of the adsorption layer is currently achieved by printing the surface of the battery cell using one or more inkjet printing nozzles. These inkjet printing nozzles can be guided in various ways, for example by means of a robot, on the surface of the vehicle battery to be printed, especially on the end side of the battery cell to be printed. Instead of using the movement of a robot for the inkjet printing nozzles, at least one inkjet printing nozzle can be moved by means of a gantry crane.

[0025] This invention generally demonstrates how a functional coating, currently an adhesion layer, can be selectively applied in the field of battery memory using a non-spraying application method.

[0026] List of reference numerals

[0027] The corresponding methods and steps for V1~V4

Claims

1. A method for manufacturing a vehicle battery, wherein, a) Multiple battery cells are arranged side by side with their central axes parallel to each other (V1). b) Each of the battery cells is electrically contacted on its end side by means of a cell contact system, thereby electrically connecting the battery cells to each other (V2). c) Coat each cell with an adhesive layer on the end side that contacts the cell contact system (V3). d) Each cell is surrounded by foam at least in the area of ​​its end that is in contact with the cell contact system (V4).

2. The method of claim 1, wherein, As an adhesion layer, a varnish (V3) is applied.

3. The method of claim 2, wherein, The applied paint hardens by being exposed to ultraviolet light (V3).

4. The method according to any of the preceding claims, characterized in that, As an adhesive layer, an electrically insulating material (V3) is used.

5. The method according to any of the preceding claims, characterized in that, As a battery cell, a circular cell (V1) is adopted.

6. The method of claim 5, wherein, The coating layer is applied to the end side of the corresponding battery cell at least in the area of ​​the shoulder of the cell (V3).

7. The method according to claim 5 or 6, characterized in that, Each battery cell has an electrical insulating film attached to its periphery before they are arranged side by side.

8. The method according to any of the preceding claims, characterized in that, The coating layer is applied by means of a printhead (V3).

9. A vehicle battery for a motor vehicle comprising: Multiple battery cells are arranged side by side with their central axes parallel to each other; And a cell contact system, wherein each cell contacts the cell contact system on its end side, thus the cells are electrically connected to each other, each cell is coated with an adhesion layer at least on its respective end side in contact with the cell contact system, and each cell is foamed with foam at least in the region of its end side in contact with the cell contact system.

10. A motor vehicle comprising the vehicle battery according to claim 9.

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