DE102015202340A1 - Cell assembly of electrochemical cells - Google Patents

Abstract

The invention relates to a cell assembly (1) of electrochemical cells (2), in particular for constructing a battery or a battery module, having a plurality of parallel and / or series-connected electrochemical cells (2), in which the individual cells (2) are insulated from each other cell housing (2). 3). According to the invention, it is provided that the insulation of the cell housing (3) is formed with one another in a region intended for insulation by a thermoplastically formable film (4) applied in common to the cell housing (3). The invention further relates to a battery module having such a cell assembly (1), and a battery pack, which has one or more such cell networks (1). Furthermore, the invention relates to a method for isolating cell housings (3) of the cells (2) of a cell assembly (1), in which the insulation of the cell housing (3) with each other in an area provided for isolation by a film (4), which in a common process step of a thermoplastic process under vacuum to the cell housing (3) of the cell assembly (1) is applied together.

Description

The invention relates to a cell assembly of electrochemical cells, in particular for constructing a battery or a battery module, having a plurality of parallel and / or series-connected electrochemical cells, in which the individual cells have cell housings insulated from one another. Furthermore, the invention relates to a battery module and a battery pack with at least one such cell assembly and a method for isolating cell housings of a cell assembly.

State of the art

Electrochemical batteries, also known as battery packs, often have a plurality of parallel and / or series-connected electrochemical cells in order to be able to meet power and / or energy requirements adapted to particular applications. Must have to provide the desired performance, such as in the case of a vehicle battery, very many cells are interconnected, is usually a modularization of the battery pack in the form of multiple battery modules.

In most cases, the cell housing of the electrochemical cells, especially in lithium-ion batteries, metallic. As a rule, the metallic cell housing forms one pole of the battery so that the cell housing is at the potential of this pole of the cell. In particular, in the case of a series connection of a plurality of cells, the cell housings of the individual cells are therefore at different potentials, so that they are to be isolated from one another.

Typically, such isolation on the masking of the cell case with insulating films, the packaging in shrink tubing, the introduction of insulating spacers, also called spacers, the use of insulating sleeves or via the painting of the cell housing. As a rule, each individual cell is isolated for itself before it is combined with other cells in later process steps to form a larger unit in the form of, for example, a battery module.

The housing of a battery cell is not carried out in any case metallic. From the publication US 3,281,283 For example, a cell of a wet battery having a one-piece housing is known wherein a non-metallic housing is made of an insulating thermoplastic material and made by a thermoforming technique of two films and vacuum forming.

Furthermore, the document describes JP 2010-33937 a lithium-ion battery in which the individual battery elements have a layered structure of electrolyte and electrode materials and are vacuum-sealed by an insulating composite film.

In the following, the term "cell assembly" refers to a plurality of parallel and / or series-connectable electrochemical cells, which are connected to one another mechanically, for example via an attachment on a common base plate.

Disclosure of the invention

Provided according to the invention is a cell assembly of electrochemical cells, in particular for constructing a battery or a battery pack, with a plurality of parallel and / or series connected electrochemical cells, in which the individual cells from each other insulated cell housing, and in which the isolation of the cell housing with each other in a for Insulation provided area is formed by a jointly applied to the cell housing thermoformable film.

Such a composite has the advantage, in particular in comparison with a composite in which the cells have been isolated separately from one another, that the cell assembly can be produced efficiently and thus inexpensively by the co-isolation of the cells with a short process time. In this case, a joint coating of the cells of a cell assembly with a film not only offers the advantage of reducing the process steps by parallelizing the isolation processes. After a single insulation of a cell by means of a film, a process step for removing excess film material is often required, which is otherwise a hindrance in the further processing of the cell. In contrast, the cell composite according to the invention has the advantage that this process step can be omitted during its production. Rather, excess Folienmateriel is advantageous for ensuring compliance with air and creepage distances usable.

Advantageously, the cell assembly for connecting the film to the cell housing means for generating a negative pressure between the film and the cell housings. Such means may be, for example, a common holding frame or a common base plate, on which a plurality of cells of the cell assembly are arranged. In this case, such a holding frame or such a base plate, for example, below the cells, for example, between the poles, also called terminals, have suction openings for forming a negative pressure or a vacuum. The means for applying the negative pressure are only during the production necessary, after cooling and solidification of the film no vacuum is necessary. Thus, as an alternative to the cell assembly, a manufacturing device may have such means.

The generation of a negative pressure has the advantage that the film of the contour of the cell housing is customizable. In particular, in the case of cells arranged next to one another, a negative pressure exerted underneath the individual cells leads to enclosing of the individual cells with foil, so that walls of adjacent cell casings can be isolated from one another. Thus, a common, tent-like spanning multiple cells can be suppressed.

Advantageously, the film has a heat-activatable adhesive layer or a heat-activatable adhesive layer is arranged between the cell housings and the film. Such a layer supports a cohesive connection between the film and the cell housings.

Further advantageously, the film is structured. A structuring of the film or the formation of a contour offers the advantage that, in the event that the cells are in contact with one another, for example because of thermal expansion, an influence on the pressure distribution between the cells can be taken via the design of the structuring.

Further advantageously, the structure of the film is advantageously designed such that the applied to the cell composite film forms an opposing patterning between walls of adjacent cell housing. In this case, an opposing structuring represents a relief or contouring produced, for example, by embossing, which can be described by a multiplicity of raised lines, and forms a multiplicity of intersections arranged on walls of opposite cell housings upon contact of the walls. This is the case, for example, with a skew hatch. An opposite structuring of the films of adjacent cell housing provides increased frictional engagement between the cells. Advantageously, the film has a structure as a Schrägschraffur of 45 °. If the film is applied to the cell housing in an orientation in which the film has a 45 ° oblique hatching with respect to the cell housing, a structuring which intersects at 90 ° is formed due to the folding between adjacent cell housings.

Also provided according to the invention is a battery module which has a cell network as described above. In this case, the isolation of all cells of the battery module is advantageously carried out as a cell network together. Such a battery module has the advantage that it is very easy to produce by a suitably interconnected cell assembly is introduced as a mechanical unit in a battery module housing.

According to the invention, a battery pack is also provided, which has one or more of the cell networks described above. In this case, such a battery pack advantageously without the formation of battery modules on one or more of the cell networks described above. By the joint isolation of cells in the form of cell networks and the mechanical connection of the cells of the cell composite with each other already a form of modularization is given, which allows, for example, a structuring within the battery pack. The formation of battery modules can thus be dispensed with.

The invention further provides a method for isolating cell housings of the cells of a cell assembly, wherein the insulation of the cell housing with each other in an area provided for isolation by a film, which is applied in a common process step of a thermoplastic process under vacuum to the cell housing of the cell assembly together becomes. According to the statements on the cell combination described above, such a method allows the isolation of the cell housings of the cells of a cell assembly in an efficient manner with only a few process steps.

In this case, the isolation of a cell composite takes place in such a way that, in a first method step, an insulating thermoplastic film is arranged over a plurality of cell housings of the cells of a cell assembly. This can be done, for example, such that the film, for example, in the heated state, is pulled over the cell assembly by means of a tenter. In a further method step, a negative pressure is generated between the heated film and the cell housings, so that the film assumes the contours of the cell housing under thermoplastic deformation. In this case, the deformation is advantageously supported by a heat-activatable adhesion layer arranged between the film and the cell housing.

The invention will be explained in more detail with reference to the accompanying drawings with reference to preferred embodiments.

Show it:

1 a group of parallel electrochemical cells;

2 a cell assembly of four cells on a base plate coated with a thermoplastic film for insulation;

3 a single cell on a base plate and a tenter with a thermoplastic film;

4 a single thermoplastic film coated cell prior to creating a negative pressure between the film and the cell;

5 a single cell isolated by means of a thermoplastic film, after adaptation of the film to the cell contour has been achieved by the generation of a negative pressure.

1 shows a group of parallel electrochemical cells 2 for the formation of a cell network 1 , The cells 2 have a prismatic, cuboid shape in this embodiment. The terminals 6 the cell 2 are oriented down and in the 1 therefore not visible. The number of cells 2 The group is basically not limited, but depends on the number of cells 2 , for the cell network 1 is provided.

2 shows a cell network 1 electrochemical cells 2 in particular for constructing a battery or a battery module, with a plurality of parallel and / or series-connectable electrochemical cells 2 in which the individual cells 2 isolated cell housing 3 and in which the insulation of the cell case 3 with each other in an area provided for isolation by a cell on the housing 3 co-applied thermoplastic moldable film 4 is trained. The cell network 1 has four cells 2 on that with their terminals 6 down on or in a base plate 5 are arranged. The foil 4 is structured, it has a structure as a 45 ° oblique hatching. This is the structure of the film 4 is designed such that the on the cell composite 1 applied foil 4 an opposite structuring between walls of adjacent cell housing 3 formed.

The 3 to 5 illustrate a preferred embodiment of the method for isolating cell housings 3 the cells 2 a cell network 1 , where the isolation of the cell case 3 each other in an area provided for insulation by a film 4 takes place, which in a common process step of a thermoplastic process under reduced pressure on the cell housing 3 of the cell network 1 is applied together. It is to better illustrate the operation of the method in the 3 to 5 only one cell at a time 2 shown.

3 shows a single cell 2 on a base plate 5 , Above is a tenter 7 with a thermoplastic film 4 shown in an unshaped initial state. For applying the heated thermoplastic film 4 to the cell 2 becomes the tenter 7 lowered. In this illustration are the downwardly oriented terminals 6 the cell 2 visible, noticeable.

4 shows the single cell 2 out 3 After the heated thermoplastic film 4 by means of the clamping frame 7 to the cell 2 was applied. The thermoplastic film 4 has the contour of the cell 2 not yet accepted. The foil 4 indicates on the side which of the cell 2 facing, a heat-activated adhesive layer on. In addition are out 4 for connecting the film 4 to the cell case 3 Means for generating a negative pressure between the film 4 and the cell case 3 seen. These funds are covered by the base plate 5 on the base plate 5 tightly lying clamping frame 7 and a suction opening (not shown) in the base plate 5 educated. The suction opening, for example, between the terminals 6 the cell 2 be arranged

The adhesive forces of the adhesive layer and a negative pressure generated via the suction opening cause the thermoplastic film 4 the contour of the cell 2 accepts.

5 shows a single by means of a thermoplastic film 4 isolated cell 2 , In this case, the thermoplastic film 4 the contour of the cell housing 3 accepted. The terminals 6 the cell 2 are so on or in the base plate 5 arranged it from the slide 4 not be overdrawn.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• US 3281283 [0005]
• JP 2010-33937 [0006]

Claims (10)

Cell network ( 1 ) electrochemical cells ( 2 ), in particular for constructing a battery or a battery module, with a plurality of parallel and / or series-connected electrochemical cells ( 2 ), in which the individual cells ( 2 ) isolated cell housing ( 3 ), characterized in that the isolation of the cell housing ( 3 ) with each other in an area provided for isolation by a on the cell housing ( 3 ) jointly applied thermoplastic moldable film ( 4 ) is trained. Cell network ( 1 ) according to claim 1, characterized in that the cell composite ( 1 ) for the connection of the film ( 4 ) to the cell housing ( 3 ) Medium ( 5 ) for generating a negative pressure between the film ( 4 ) and the cell housings ( 3 ) having. Cell network ( 1 ) according to claim 1 or claim 2, characterized in that between the cell housings ( 3 ) and the film ( 4 ) a heat-activatable adhesive layer is arranged or the film ( 4 ) has a heat-activatable adhesive layer. Cell network ( 1 ) according to one of the preceding claims, characterized in that the film ( 4 ) is structured. Cell network ( 1 ) according to claim 4, characterized in that the structure of the film ( 4 ) is designed such that the on the cell composite ( 1 ) applied film ( 4 ) an opposing structuring between walls of adjacent cell housing ( 3 ) trains. Cell network ( 1 ) according to claim 4 or claim 5, characterized in that the film ( 4 ) has as a structure a 45 degree oblique hatching. Battery module, characterized in that it has a cell network ( 1 ) according to one of claims 1 to 6. Battery pack characterized in that it comprises one or more cell networks ( 1 ) according to one of claims 1 to 7. Battery pack characterized in that it without the formation of battery modules one or more cell networks ( 1 ) according to one of claims 1 to 7. Method for isolating cell housings ( 3 ) of the cells ( 2 ) of a cell network ( 1 ), characterized in that the isolation of the cell housing ( 3 ) with each other in an area provided for insulation by a film ( 4 ), which in a common process step of a thermoplastic process under reduced pressure on the cell housing ( 3 ) of the cell network ( 1 ) is applied together.

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