DE102019208063A1 - Method for producing a battery cell and battery cell - Google Patents

Abstract

The invention relates to a method for producing a battery cell (2), wherein a surface (6) of a battery cell component (8) provided for joining with a sealing or insulating element (4) is structured by means of an electron beam, and wherein the battery cell component (8) in the area of the structured surface (6) is joined to the sealing or insulating element (4) in a form-fitting manner. The invention also relates to such a battery cell (2) and an electrically powered motor vehicle (42) with a battery (44) which has such a battery cell (2).

Description

The invention relates to a method for producing a battery cell, wherein a sealing or insulating element is joined to a battery cell component. The invention also relates to such a battery cell and an electrically powered motor vehicle with a battery which has such a battery cell.

An electrically driven motor vehicle typically has a (traction) battery designed as a lithium-ion battery, which supplies an electric motor with energy to drive the motor vehicle. An electrically powered motor vehicle is in particular an electric vehicle that stores the energy required for propulsion only in the battery (BEV, battery electric vehicle), an electric vehicle with a range extender (REEV, range extended electric vehicle), a hybrid vehicle (HEV, hybrid electric vehicle), a plug-in hybrid vehicle (PHEV, plug-in hybrid electric vehicle) and / or a fuel cell vehicle (FCEV, fuel cell electric vehicle), which temporarily stores the electrical energy generated by a fuel cell in the battery.

Such a battery has several battery cells, which should be gas- and liquid-tight for safe operation. In particular, leakage of liquid electrolyte from the battery cell and / or penetration of water into the battery cell are to be avoided. In addition, no part of the battery cell, which is referred to below as a battery cell component, should be in electrical contact with both poles of the battery cell.

For example, a sealing or insulating element, which is attached to the corresponding battery cell component, is used as a liquid and gas seal and / or for electrical insulation. For example, the surface of the battery cell component is provided with a coating in order to improve the adhesion of the sealing or insulation element to it. For example, a battery cell component made of aluminum is chromated or coated with zirconium. A battery cell component made of copper is coated with nickel, for example. As a result of the coating, properties of the surface of the battery cell component are changed. With a nickel layer, for example, the hardness of the surface is increased. Any further steps necessary for the production of the battery cell, for example welding a further component onto the nickel-coated surface by means of ultrasound, are disadvantageously made more difficult. Furthermore, such a coating is comparatively cost-intensive.

It is also known to structure surfaces by means of a laser. However, when structuring a surface by means of a laser, there is a comparatively high thermal energy input and, associated therewith, a comparatively high risk of oxidation on the surface and / or a comparatively large heat-affected zone.

The invention is based on the object of specifying a particularly suitable method for producing a battery cell. In particular, a sealing or insulation element should be joined to the battery cell component as reliably as possible and / or the production of the battery cell should be as cost-effective as possible. Furthermore, such a battery cell and a motor vehicle with a battery are to be specified which has such a battery cell.

With regard to the method, the object is achieved according to the invention by the features of claim 1. With regard to the battery cell, the object is achieved with the features of claim 9 and with regard to the motor vehicle with the features of claim 10. Advantageous refinements and developments are the subject of the dependent claims. The explanations in connection with the method also apply accordingly to the battery cell and to the motor vehicle and vice versa.

According to the method for producing a battery cell, in a first step a surface of a battery cell component provided for joining with a sealing or insulating element is structured by means of an electron beam.

The battery cell component is expediently formed from a metal or has at least one metal. The electron beam acts on the battery cell component. In particular, material of the battery cell component is correspondingly melted and / or evaporated while forming a (surface) structure. In summary, the surface structure is therefore not applied to the battery cell component but is introduced into the battery cell component.

In a second step of the method, the battery cell component is positively joined to the sealing or insulation element in the area of the structured surface. The sealing or insulating element is suitably formed from a plastic. The sealing or insulation element is thus an element by means of which a battery cell housing of the battery cell is sealed, that is to say closed airtight and liquid-tight, and / or by means of which two battery cell components are electrically isolated from one another.

In particular, the battery cell is designed as a lithium-ion battery cell. The battery cell is suitably provided for a (traction) battery of an electrically driven motor vehicle.

A “form fit” or a “form fit connection” between at least two interconnected parts is understood here and in the following in particular to mean that the interconnected parts are held together at least in one direction by direct interlocking of contours of the parts themselves or by indirect interlocking takes place via an additional connecting part. The "blocking" of a mutual movement in this direction is therefore due to the shape.

A comparatively reliable connection of the sealing or insulation element to the battery cell component is advantageously realized due to the form fit. Furthermore, due to the form fit, no additional coating, as described above, is necessary for a reliable connection of the sealing or insulation element to the battery cell component. A comparatively cost-saving production of the battery cell is thus achieved. Furthermore, an undesired change in the surface properties of the battery cell component due to the coating is avoided.

According to a suitable embodiment of the method, the battery cell component and the sealing or insulation element to be joined with it are pressed against one another. The sealing or insulation element is preferably additionally heated. As a result, there is at least a slight deformation of the sealing or insulation element with the formation of the form fit with the surface structure of the battery cell component.

According to a suitable embodiment, a regular surface structure is introduced into the surface of the battery cell component. In particular, structural elements of the surface structure are regularly arranged and / or regularly formed. The structural elements are preferably arranged in a periodically repeating manner, spaced equidistantly from one another, and / or formed symmetrically. A regular surface structure and the associated reliability of the form fit between the battery cell components and the sealing or insulating element is advantageously comparatively easy to reproduce.

For example, the structural elements are designed as pore-like, hemispherical or prismatic depressions, or as mushroom-head-shaped, prism-shaped or hemispherical elevations. Alternatively, the surface structure is designed, for example, as a roughening of the surface.

The introduction of such a surface structure by means of the electron beam is expediently carried out in a vacuum. For this purpose, the battery cell component is introduced into a vacuum chamber in the course of processing with the electron beam. A vacuum is understood here to mean in particular an environment at a pressure of less than 10 ^-4 mbar. Thus, the structural elements shown above can be introduced into the surface with comparative precision.

As an alternative to this, such a surface structure is introduced by means of the electron beam at ambient pressure. Due to a scattering of the electrons on the particles in the atmosphere, randomly distributed, in particular pore-like, depressions with a random depth are made in the surface. A vacuum chamber for the battery cell component is not necessary here, so that a device for carrying out the method has a comparatively simple structure.

According to an expedient embodiment, a defocused electron beam is used to structure the surface. The focus of the electron beam is therefore not arranged in the processing plane formed by means of the surface. In particular, the defocused electron beam is used to introduce an irregular, that is to say randomly formed, surface structure.

In comparison to the structuring of the surface by means of a laser mentioned at the beginning, in which each of the pore-like depressions has to be introduced individually, several pore-like depressions, also referred to as surface perforations, or a roughening of the surface by means of the electron beam on a comparatively large one, are advantageously made here by means of the electron beam Area introduced. A time-saving production of the surface structure and thus the battery cell is thus achieved.

According to a suitable embodiment, the battery cell is designed as a prismatic cell, a housing cover being used as the battery cell component and an insulating tape being used as the sealing or insulating element. In other words, in the case of a battery cell designed as a so-called prismatic cell, the surface becomes whose housing cover is structured by means of the electron beam and the housing cover is joined to the insulating tape in the area of the structured surface.

The insulation tape is expediently arranged on the housing cover in such a way that it effects electrical insulation of the terminals of the battery cell when the battery is installed. For this purpose, the insulating tape is expediently arranged in a region of the housing cover which, in the assembled state, is arranged adjacent to and / or in contact with the respective terminal.

In the case of a battery cell designed as a prismatic cell, in a suitable embodiment, the terminal is additionally or alternatively used as a battery cell component and a sealing frame for the terminal is used as a sealing or insulating element. In particular, the sealing frame is arranged on the peripheral side of the terminal, so that it is arranged between the terminal and the housing cover when the battery cell is in the assembled state. The sealing frame thus acts both as a liquid and gas seal and as an electrical insulation for the terminal from the housing cover. If the terminal is formed from several components, each of the components or a partial number of the components are each provided with a surface structure and provided with a respective sealing or insulating element, the terminal being then assembled and installed. Alternatively, the components of the terminal are first joined together and then provided with a surface structure that is joined in a form-fitting manner with a common sealing or insulation element.

According to an alternative embodiment, in which the battery cell is designed as a pouch cell, a cell arrester is used as the battery cell component and a pre-sealing tape is used as the sealing or insulating element. The presealing tape expediently encompasses the respective cell arrester on the circumference.

The presealing tape, which is expediently designed to be electrically insulating, is expediently arranged between the cell arrester and a housing foil in the assembled state of the pouch cell. The pre-sealing tape serves as a liquid and gas seal for the housing opening through which the cell arrester protrudes.

According to a further alternative embodiment, the battery cell is designed as a frame flat cell, with a housing side, in particular designed as a side sheet (cladding sheet), being used as the battery cell component and a sealing frame as a sealing or insulating element. The side of the housing side facing a further housing side is structured in the circumferential area. The surface that is structured according to the method is therefore arranged on this side of the housing in the circumferential area.

The sealing or insulation element designed as a sealing frame serves as a liquid and gas seal and for electrical insulation, the sealing frame being arranged between the housing side and the further housing side. For example, the two sides of the housing are shell-shaped with a circumferential joining flange by means of deep drawing. When the battery cell is in the assembled state, the sealing frame is then arranged between the joining flanges of the two housing sides. As an alternative to this, when the battery cell is in the assembled state, a frame is introduced between the housing side and the further housing side, the sealing frame being arranged between the housing side and the frame. The sealing frame is expediently joined to the frame or is part of the frame.

According to an expedient embodiment, a battery cell is produced according to the method in one of the variants presented above. In particular, a surface of one of its battery cell components is provided with a surface structure by means of an electron beam. The battery cell component is also joined to the sealing or insulation element in a form-fitting manner in the area of the structured surface.

According to an expedient embodiment, an electrically driven motor vehicle has a battery with a battery cell, the battery cell being produced according to one of the above-described variants of the method. The battery is preferably a traction battery which supplies an electric motor with electrical energy to drive the motor vehicle.

• 1 in einem Flussdiagramm einen Verfahrensablauf zur Herstellung einer Batteriezelle, bei welchem eine Oberfläche einer Batteriezellen-Komponente mittels einer Elektronenstrahls strukturiert wird, und bei welchem die Batteriezellen-Komponente im Bereich der Oberflächenstruktur mit einem Siegel- oder Isolationselement gefügt wird,
• 2a bis 2d in schematischer Darstellung unterschiedliche Varianten der Oberflächenstruktur mit als porenartige Vertiefungen, als Aufrauhung, als halbkugelförmige Vertiefungen und bzw. als pilzkopfförmige Erhebungen ausgebildeten Strukturelementen,
• 3 in einer schematischen Schnittdarstellung eine als prismatische Zelle ausgebildete Batteriezelle, deren Gehäusedeckel formschlüssig mit einem Isolationsband gefügt ist, und wobei deren Terminal formschlüssig mit einem Siegelrahmen gefügt ist,
• 4a schematisch in einer perspektivischen Ansicht einen Zell-Ableiter einer als Pouchzelle ausgebildeten Batteriezelle, wobei der Zell-Ableiter umfangsseitig mit einem Vorsiegelband gefügt ist,
• 4b in einer schematischen Schnittdarstellung die als Pouchzelle ausgebildete Batteriezelle, wobei das Vorsiegelband zwischen dem Zell-Ableiter und einer Gehäusefolie angeordnet ist,
• 5a in einer schematischen Schnittdarstellung eine als Rahmenflachzelle ausgebildete Batteriezelle, wobei das Batteriegehäuse mittels zweier schalenförmiger Gehäuseseiten gebildet ist, welche an deren Fügeflanschen miteinander mittels eines zwischen den Fügeflanschen angeordneten Siegelrahmens gefügt sind,
• 5b schematisch in einer perspektivischen Explosionsdarstellung eine alternative Ausgestaltung der als Rahmenflachzelle ausgebildeten Batteriezelle, wobei ein Rahmen zwischen zwei ebenen Gehäuseseiten angeordnet ist, und wobei jeweils zwischen dem Rahmen und den Gehäuseseiten ein Siegelrahmen angeordnet ist, und
• 6 in einer schematischen Draufsicht ein elektrisch angetriebenes Kraftfahrzeug, welches eine Batterie mit einer Anzahl an Batteriezellen aufweist.

Exemplary embodiments of the invention are explained in more detail below with reference to a drawing. Show in it:

• 1 in a flow chart a process sequence for the production of a battery cell, in which a surface of a battery cell component is structured by means of an electron beam, and in which the battery cell component is joined in the area of the surface structure with a sealing or insulation element,
• 2a to 2d In a schematic representation, different variants of the surface structure with as pore-like depressions, as roughening, as hemispherical Depressions and structural elements designed as mushroom-head-shaped elevations,
• 3 in a schematic sectional view of a battery cell designed as a prismatic cell, the housing cover of which is positively joined to an insulating tape, and the terminal of which is positively joined to a sealing frame,
• 4a schematically, in a perspective view, a cell arrester of a battery cell designed as a pouch cell, the cell arrester being joined on the circumference with a presealing tape,
• 4b in a schematic sectional view the battery cell designed as a pouch cell, with the pre-sealing tape being arranged between the cell arrester and a housing film,
• 5a in a schematic sectional view of a battery cell designed as a frame flat cell, the battery housing being formed by means of two shell-shaped housing sides which are joined to one another at their joining flanges by means of a sealing frame arranged between the joining flanges,
• 5b schematically in a perspective exploded view an alternative embodiment of the battery cell designed as a frame flat cell, wherein a frame is arranged between two flat housing sides, and wherein a sealing frame is arranged between the frame and the housing sides, and
• 6th in a schematic plan view an electrically powered motor vehicle which has a battery with a number of battery cells.

Corresponding parts and sizes are always provided with the same reference symbols in all figures.

That in the 1 The flowchart shown represents a method for producing a battery cell 2 . In a first step I. becomes one for joining with a sealing or insulating element 4th intended surface 6th a battery cell component 8th structured by means of an electron beam. In other words, the electron beam acts on the battery cell component to form the surface structure 8th a, with corresponding material of the battery cell component on the surface 6th melted and / or evaporated.

In a subsequent second step II of the procedure is the battery cell component 8th in the area of the structured surface 6th form-fitting with the sealing or insulation element 4th joined. For this purpose, the battery cell components 8th and the sealing or insulation element to be joined with it 4th pressed against each other. The form fit of the sealing or insulation element 4th with the surface structure of the battery cell component 8th takes place due to an at least slight deformation of the sealing or insulation element 4th .

The battery cell component 8th is made of a metal and the sealing or insulating element 4th formed from a plastic.

Different variants of this way in the surface 6th introduced surface structure are in the 2a to 2d shown.

The ones in the 2a The surface structure shown is by means of pore-like depressions as structural elements 10 educated. These are randomly (statistically) distributed and have different shapes from one another. The introduction of such a surface structure by means of the electron beam takes place at ambient pressure. The electrons of the electron beam are scattered by the particles in the atmosphere, so that the electrons are randomly distributed with a corresponding energy on the surface 6th hit to form the pore-like depressions.

In the 2 B is has the surface 6th a roughening introduced by means of the electron beam. To introduce such a roughening, a defocused electron beam, that is to say an electron beam, whose focus is not in the means of the surface 6th formed processing plane is used. The introduction of this roughening by means of the electron beam takes place in a vacuum. The battery cell component 8th is introduced into a vacuum chamber (not shown) in the course of processing with the electron beam. Alternatively, the roughening according to the 2 B into the surface at ambient pressure 6th brought in.

According to a variant not shown further, pore-like or blind hole-like depressions are made in the surface by means of a defocused electron beam 6th brought in. The introduction of these depressions by means of the electron beam also takes place in a vacuum.

In the 2c and 2d regular surface structures are shown. The surface structure is here by means of structural elements designed as hemispherical depressions or as mushroom-head-shaped elevations 10 educated. The respective structural elements 10 the surface structure are arranged regularly and regularly trained. The introduction of these surface structures by means of the electron beam also takes place in a vacuum and expediently with a focused electron beam.

By means of the sealing or insulating element 4th becomes a battery cell housing of the battery cell 2 sealed, i.e. closed airtight and liquid-tight, and / or two battery cell components 8th electrically isolated from one another. Exemplary embodiments of the battery cell component 8th and the sealing or insulating element 4th are in the 3 to 5a shown.

In the 3 is a part of a battery cell designed as a prismatic cell 2 shown. The battery cell 2 has a housing cover 12th on, which is on both sides, so both on the housing interior 14th facing side as well as on the side facing the environment with an insulating tape 16 trained sealing or insulation element 4th form-fitting in the area whose surface structure is joined. The surface structure is not shown further for the purpose of better visibility. By means of the insulation tape 16 is an electrical insulation of a terminal 18th to the housing cover 12th causes. The insulation tape 16 extends completely along the interior of the housing 14th facing side and the side of the housing cover facing the environment 12th . According to an alternative not shown further, the insulating tape extends 16 only in the area of the terminal 18th .

The terminal 18th sits in a housing cover opening 20th one. The terminal 18th has an internal contact on the inside of the housing 22nd electrically contacted, which in turn with anodes or cathodes, not shown, of the battery cell 2 is electrically contacted. Furthermore is in the terminal 18th circumferentially on the housing cover 12th facing a surface structure introduced by means of the electron beam and in the area of the structured surface 6th positively according to the procedure 1 with one the terminal 18th sealing frame encompassing the circumference 24 joined. The surface structure is not shown here.

The terminal 18th is in the 3 shown only schematically. The terminal 18th has, for example, several components. At most, the battery cell is 2 in the area of the terminal 18th by means of the sealing frame 24 sealed gas and liquid tight.

In summary are the terminal 18th as well as the housing cover 12th in the area of their surface structured by means of an electron beam 6th each with one as a sealing frame 24 or as insulation tape 16 Sealing or isolation element 4th joined.

In the 4a is a cell arrester 26th a battery cell designed as a pouch cell 2 shown. Its surface 6th is structured by means of an electron beam. This is the structured area of the cell arrester 26th Shown flat and dotted and partly from the cell arrester 26th hidden due to the presentation. On the circumference of the cell arrester 26th is in the area of its structured surface 6th one as a pre-sealing tape 28 formed sealing or insulating element 4th arranged and form-fitting according to the method 1 joined.

In the sectional view of the 4b is the cell arrester 26th with the isolation element 4th in the assembly state of the battery cell 2 shown. The sealing tape 28 is here between the cell arrester 26th and two housing sheets forming the housing 30th arranged. The pre-sealing tape has an electrically insulating effect and serves as a liquid and gas seal for a housing opening in which the cell arrester 26th is arranged. Im by means of the housing foils 30th housing interior formed 14th is the cell arrester 26th with anodes or cathodes of the battery cell not shown 2 electrically connected.

In the 5a is a first variant of a battery cell designed as a frame flat cell 2 shown. This has two shell-shaped housing sides 32 which are each formed by means of a deep-drawn sheet metal. The shell-shaped housing sides 32 so each have a tray bottom 34 on, on which a shell wall oriented perpendicular to this 36 is molded. The free end is on the shell wall 36 one along the perimeter of the shell wall 36 and to the (housing) outside extending joining flange 38 molded. In the joining flanges 38 the two sides of the housing 32 are on the other side of the housing 32 facing side a surface structure not shown by means of the electron beam according to the method of 1 brought in. In summary, the sides of the case 32 in the circumferential area of the other side of the housing 32 facing side structured. In addition, the joining flanges are 38 both sides of the housing 32 with a common one between the joining flanges 38 arranged sealing frame 24 positively joined. The structured surfaces 6th the two sides of the housing 32 are therefore opposite each other, with the seal frame between them 24 trained sealing or isolation element 4th is arranged.

In the 5b is an alternative embodiment of the battery cell designed as a frame flat cell 2 shown. Here are the two sides of the housing 32 the battery cell 2 flat, with a frame between them 40 is arranged. The two sides of the case 32 are each in a peripheral area of the frame 40 facing side with one after the in the 1 The method shown provided surface structure introduced. In the 5b is the structured surface 6th is shown flat dotted.

Between the sides of the case 32 and the frame 40 is that as a seal frame 24 trained sealing or isolation element 4th arranged, which form-fit with the respective housing side in the area of their structured surface 6th is joined. In addition, the sealing frames are 24 each joined to the frame so that the battery cell 2 is liquid and gas tight.

In summary, this serves as a sealing frame 24 trained sealing or isolation element 4th the 5a and 5b as a liquid and gas seal and for electrical insulation of the two sides of the housing 32 to each other.

In 6th is a motor vehicle 42 with a (traction) battery 44 shown. The battery 44 has a battery case 46 in which a number of cell modules 48 is recorded. For the sake of clarity there are only six cell modules 48 shown. Each of the cell modules 48 again has a cell module housing 50 with a number of battery cells received therein 2 , of which only three are exemplified per cell module 48 are shown.

The battery cells 2 are according to one of the variants of 3 to 5b educated. In addition, the battery cells are 2 interconnected in a manner not shown. For example, the battery cells 2 of each cell module 48 parallel to each other and the cell modules 48 connected to one another in series and / or parallel to one another, so that at load connections 52 the battery 44 a voltage or a current is provided which or which is used to operate one at the load connections 52 connected consumer 54 suitable is. For this purpose, battery cell connections, for example designed as terminals, are used 56 of the battery cells 2 correspondingly (electrically) connected to each other. For example, is the consumer 54 an inverter of a drive train of the motor vehicle 42 which inverter is used by the battery 44 converts the provided direct current into an alternating current suitable for operating an electric motor (not shown).

The invention is not restricted to the exemplary embodiments described above. Rather, other variants of the invention can also be derived from this by the person skilled in the art without departing from the subject matter of the invention. In particular, all of the individual features described in connection with the exemplary embodiments can also be combined with one another in other ways without departing from the subject matter of the invention.

List of reference symbols

2

Battery cell

4th

Sealing or isolation element

6th

surface

8th

Battery cell component

10

Structural element

12

Housing cover

14th

Housing interior

16

Insulation tape

18th

terminal

20th

Housing cover opening

22nd

inner contact

24

Sealing frame

26th

Cell arrester

28

Pre-sealing tape

30th

Housing foil

32

Housing side

34

Tray bottom

36

Shell wall

38

Joining flange

40

frame

42

Motor vehicle

44

battery

46

Battery case

48

Cell module

50

Cell module housing

52

Load connection

54

consumer

56

Battery cell connection

I.

Structuring the surface of the battery cell component

II

Joining the battery cell component with the sealing or insulation element

Claims (10)

Method for producing a battery cell (2), - wherein a surface (6) provided for joining with a sealing or insulating element (4) is a Battery cell component (8) is structured by means of an electron beam, and - wherein the battery cell component (8) is positively joined to the sealing or insulation element (4) in the area of the structured surface (6). Procedure according to Claim 1 , characterized in that the battery cell component (8) and the sealing or insulating element (4) to be joined therewith are pressed against one another. Procedure according to Claim 1 or 2 , characterized in that a regular surface structure is introduced into the surface (6) of the battery cell component (8). Method according to one of the Claims 1 to 3 , characterized in that a defocused electron beam is used to structure the surface (6). Method according to one of the Claims 1 to 4th , characterized in that the battery cell (2) is designed as a prismatic cell, a housing cover (12) being used as the battery cell component (8) and an insulating tape (16) being used as the sealing or insulating element (4). Method according to one of the Claims 1 to 5 , characterized in that the battery cell (2) is designed as a prismatic cell, a terminal being used as the battery cell component (8) and a sealing frame for the terminal being used as the sealing or insulating element (4). Method according to one of the Claims 1 to 4th , characterized in that the battery cell (2) is designed as a pouch cell, a cell arrester (26) being used as the battery cell component (8) and a presealing tape being used as the sealing or insulating element (4). Method according to one of the Claims 1 to 4th , characterized in that the battery cell (2) is designed as a frame flat cell, a housing side (32) being used as the battery cell component (8), the side of which facing a further housing side (32) is structured in the circumferential area, and as a seal - or insulation element (4) a sealing frame (24) is used. Battery cell (2) produced according to the method according to one of the Claims 1 to 8th . Electrically powered motor vehicle (42) with a battery (44) which has a battery according to the method of one of the Claims 1 to 8th manufactured battery cell (2) comprises.

Images