EP2764561A1

EP2764561A1 - Method and system for cutting sheet-shaped or plate-shaped objects

Info

Publication number: EP2764561A1
Application number: EP12734812.6A
Authority: EP
Inventors: Steffen Legner
Original assignee: Li Tec Battery GmbH
Current assignee: Li Tec Battery GmbH
Priority date: 2011-10-06
Filing date: 2012-07-05
Publication date: 2014-08-13
Also published as: WO2013050088A1; DE102011115118A1

Abstract

The invention relates to a method for cutting sheet-shaped or plate-shaped objects (1) having thermoplastic synthetic fibres as substrate material, in particular electrodes and/or separators for the construction of an electrochemical energy accumulator or parts of such electrodes or separators, said method including the steps of: (S1) guiding the objects (1) to be cut towards a laser cutting device (2), and (S2) cutting the objects (1) with the laser cutting device (2) in such a way that a fusion of at least some of the thermoplastic synthetic fibres is carried out on the cut edges (3). The invention further relates to a system (10) for cutting sheet-shaped or plate-shaped objects (1) having thermoplastic synthetic fibres as substrate material, in particular for cutting electrodes and/or separators for the construction of an electrochemical energy accumulator or parts of such electrodes or separators, wherein the cutting system (10) includes a transport device (5), which is configured for guiding the objects (1) to be cut towards a laser cutting device (2), and a laser cutting device (2) which is configured for cutting the objects (1) such that a fusion of at least some of the thermoplastic synthetic fibres is performed on the cut edges (3).

Description

Method and system for cutting sheet or plate-shaped

objects

Description

The present invention relates to a method and a system for cutting thermoplastic plastic fibers as carrier material having sheet- or plate-shaped objects, in particular for cutting electrodes and / or separators for the construction of an electrochemical energy storage or parts of such electrodes or separators.

Hereby, the entire contents of the priority application DE 10 201 1 1 15 1 18 by reference is part of the present application.

As electrochemical energy storage batteries (primary storage) and accumulators (secondary storage) are known, which are composed of one or more memory cells in which upon application of a charging current, electrical energy in an electrochemical charging reaction between a cathode and an anode in or between an electrolyte in chemical Energy is converted and stored and in which when connecting an electrical load chemical energy is converted into electrical energy in an electrochemical discharge reaction. Primary storage is typically charged only once and disposed of after discharge, while secondary storage allows multiple (from a few 100 to over 10,000) cycles of charge and discharge. It should be noted in this context that, especially in the motor vehicle sector, rechargeable batteries are also referred to as batteries.

The electrodes and separators are needed in a very large number, which is why there is a need for high quality, effective and cost effective Manufacturing process exists. When manufacturing the electrodes and separators, it should be noted that these components must be cut to the appropriate dimensions for the assembly of the electrode stacks or cells. For a continuous production line, the electrodes and the separators are cut from electrode strips or separator strips.

It is therefore an object of the present invention to provide an improved method and system for cutting thermoplastic resin fibers as sheet or plate shaped substrates having support material. This object is achieved by a method according to claim 1, a cutting system according to claim 16 and a battery according to claim 22. Advantageous embodiments and further developments are the subject of the dependent claims.

According to a first aspect, this object is achieved in a method for cutting thermoplastics fibers as carrier material having sheet- or plate-shaped objects, in particular of electrodes and / or separators for constructing an electrochemical energy store or parts of such electrodes or separators, that the cutting process comprising the steps of: bringing the objects to be cut to a laser cutting device and cutting the objects with the laser cutting device such that fusion of at least part of the thermoplastic resin fibers is performed at the cutting edges. One advantage of this embodiment is that the at least partial fusion at the cut edges enables a simplified handling of the electrodes and separators, since the risk of micro-cracks during mechanical stress during assembly can be reduced. Another advantage lies in the fact that the increased strength at the cutting edges, the life of the electrodes and the separators is increased and that batteries can be run through with such produced electrodes and separators an increased number of cycles. Opposite Conventional mechanical cutting methods are advantages of the cutting method according to the invention in that a constant quality of the cut edges can be achieved and that no mechanical stress acts on the cut edges and that fewer particles are generated in this cutting process, so that during the preparation of the cleaning of the electrodes and the separators is simplified. Further advantages of the cutting method according to the invention are that the method can be carried out wear-free and that the production of different geometries of the electrodes and the separators is simplified. Another advantage over mechanical cutting methods lies in the fact that the cut edges have a smooth cutting profile.

In the context of this invention, an "electrochemical energy store" is to be understood as meaning any type of energy store from which electrical energy can be taken, wherein an electrochemical reaction takes place in the interior of the energy store comprises at least one electrochemical cell, preferably a plurality of electrochemical cells The plurality of electrochemical cells may be connected in parallel to store a larger amount of charge or may be connected in series to achieve a desired operating voltage or form a combination of parallel and series connection.

In the context of this invention, an "electrochemical cell" is to be understood as meaning a device which serves to deliver electrical energy, the energy being stored in a chemical form, In the case of rechargeable secondary batteries, the cell is also designed to receive electrical energy. The shape (ie, in particular, the size and geometry) of an electrochemical cell can be chosen depending on the available space, Preferably, the electrochemical cell is substantially prismatic or cylindrical The present invention is particularly applicable to electrochemical cells used advantageously as pouch cells or Coffeebag cells without the electrochemical cell of the present invention should be limited to this application.

Such an electrochemical cell usually has an electrode stack, which is at least partially enclosed by an envelope. For the purposes of the present invention, an "electrode stack" is to be understood as meaning an arrangement of at least two electrodes and an electrolyte arranged therebetween The electrolyte may be partially received by a separator, the separator then separating the electrodes The electrodes are for example plate-shaped or foil-like and are preferably arranged substantially parallel to each other (prismatic energy storage cells) .The electrode stack may also be wound and one The term "electrode stack" should also include such electrode windings. The electrode stack may also comprise lithium or another alkali metal in ionic form.

In the context of this invention, a "sheet-like or plate-shaped object" is to be understood as meaning a substantially flat article, preferably a thin flat article The thermoplastic resin fibers preferably comprise a thermoplastic polyester, in particular polythylene terephthalate, in the process.

Preferably, in the method, the step of cutting the objects from the laser cutting apparatus is performed at least partially with a pulsed laser having at least one of the following characteristics: a maximum wavelength in a wavelength range of 400 nm to 1300 nm, preferably maximum wavelength in a wavelength range and particularly preferably a maximum wavelength of 1070 nm, a pulse duration in a pulse duration range of 5 ps to 200 ns, preferably a pulse duration of 30 ns, a frequency in a frequency range of 40 kHz to 5000 kHz, preferably from 250 kHz to 1000 kHz and a frequency of 500 kHz, an overlap of more than 50%, preferably an overlap of more than 90%, a beam quality <2 M ² ; a power in a power range of 1 kW to 20 kW, preferably a power of 5 kW, a laser spot size smaller than 1000 μητι, preferably a laser spot size smaller than 300 pm. Preferably, in the method, the step of cutting the objects from the laser cutting device at a cutting speed in a speed range of 0.01 m / s to 20 m / s, preferably in a speed range of 0.05 m / s to 6.0 m / s and more preferably in a speed range of 0.5 m / s to 4.0 m / s performed. Preferably, in the method in the step of cutting the objects, the cut edges of the objects are above a slit of a slotted overlay. Advantages of this embodiment are that heat accumulation in the region of the support can be avoided and that resulting cutting gases can be sucked off both above and below the objects to be cut.

Preferably, the method comprises performing machining operations on the cut edges, in particular performing machining operations on the cut edges to reduce micro-shorts. This embodiment has the advantage that the cutting operations can be carried out quickly and the cutting edges have a quality required for further use, since the machining operations at the cutting edges can be used to avoid or reduce the shortcomings of the microstructure

Preferably, in the method, the step of performing machining operations on the cut edges to reduce microcracking Conclude structuring the cut edges. An advantage of this embodiment is that microshorting can be avoided particularly quickly and effectively by such structuring

Preferably, in the method, the step of patterning the cut edges is performed with a laser structuring device.

According to a further embodiment, the step of structuring the cut edges with the laser structuring device is preferably performed after the step of cutting the object with the laser cutting device. Preferably, in the method, the step of patterning the cut edges with the laser structuring device is performed prior to the step of cutting the object with the laser cutting device.

Preferably, in the method of the step of patterning the cut edges as the laser patterning apparatus, the laser cutting apparatus is used.

According to a further embodiment, the step of structuring the cut edges with the laser structuring apparatus and the step of cutting the objects with a laser cutter are performed substantially simultaneously. Preferably, in the method, the step of performing machining operations on the cut edges to reduce micro-shorts comprises applying support materials to the cut edges.

Preferably, in the method, the step of applying under-backing materials to the cut edges and the step of cutting the objects with the laser cutter are performed substantially simultaneously. An advantage of this embodiment is that the cutting can be assisted with a laser beam Preferably, in the method, the support materials have components with increased absorption coefficients with respect to the wavelengths used by the laser cutting device.

According to a second aspect, this object is achieved in a system for cutting thermoplastic plastic fibers as carrier material having sheet or plate-shaped objects, in particular for cutting electrodes and / or separators for the construction of an electrochemical energy store or parts of such electrodes or separators, thereby solved the cutting system a transport device configured to bring the objects to be cut to a laser cutting device; and a laser cutting device configured to cut the objects such that fusion of at least a portion of the thermoplastic resin fibers is performed at the cutting edges.

Preferably, the cutting system has a processing device which is designed to carry out processing operations on the cut edges to reduce micro-short-circuits.

In the case of the cutting system, the processing device preferably has a laser structuring device which is designed to structure the cut edges. In the cutting system, the processing device preferably has a material application device that is designed to apply support materials to the cut edges.

The laser cutting device preferably has an ytterbium fiber laser, which has proved to be particularly advantageous for cutting polyethylene terephthalate.

With regard to the advantages of this cutting system and the terms used, the statements made above in connection with the cutting method according to the invention apply correspondingly. The present invention also relates to an electric cell for an electrochemical energy storage device having separators cut by a cutting method as mentioned above and / or produced by means of a cutting system as mentioned above.

Further advantages, features and applications of the present invention will become apparent from the following description taken in conjunction with the drawings. Show it:

Fig. 1 is a schematic representation of a cutting system according to a

Embodiment of the invention and

Fig. 2 is a flowchart for a cutting method after a

Embodiment of the invention.

The present invention will be described below using the example of cutting separators and electrodes for an electrochemical energy store.

Fig. 1 shows a schematic representation of a cutting system 10 according to an embodiment of the present invention. The cutting system 10 has a transporting device 5, which has for the introduction of the thermoplastic fibers to be cut as a carrier material

Separatorenbandes 1 or the thermoplastic fibers to be cut as carrier material having electrode tape 1 is configured to a laser cutting device 1. The laser cutting device 2 intersects the separator belt 1 or the electrode belt at the cutting edge 3 with a laser cutting beam 2a. The laser cutting device 2 is configured in such a way that at least one part of the thermoplastic polymer fibers is fused when cutting at the cutting edges 3.

In Fig. 1 it is shown that preferably the cutting operation with a

Material beam 6a of the material application device 6 can be supported on the cutting edge 3. Furthermore, in FIG. 1, a laser structuring Device 4, which can structure the Separatorenband 1 or the electrode strip at the cutting edge 3 with a laser structuring beam 4a. After the cutting operations, the separators 1 'cut from the separator belt 1 or the electrodes cut from the electrode belt are removed from the cutting system 10 with the removal device 7.

Fig. 2 shows a flow chart for a cutting method according to an embodiment of the present invention. The separator belt 1 to be cut is brought to the laser cutting device 2 in a step S1. In a step S2, the separators 1 'are cut out of the separator belt 1 with the laser cutting device 2 in such a way that at least one part of the thermoplastic synthetic fibers is cut at the cut edges 3 during cutting, whereby according to a preferred embodiment and in FIG. 2, in a step S3, machining operations are performed on the cut edges 3 in order to reduce microshorts. According to the embodiment shown in FIG. 2, step S3 is performed after step S2. However, it is also possible, according to another embodiment not shown in FIG. 2, to carry out the steps S2 and S3 simultaneously. According to another embodiment, not shown in FIG. 2, it is also possible to carry out the step S3 before the step S2. In FIG. 2, it is shown that the step S2 of performing machining operations on the cut edges 3 a

Structuring the cut edges 3 and / or application of support materials may have at the cutting edges 3.

LIST OF REFERENCE NUMBERS

1 object to be cut

1 "cut object

2 laser cutting device

2a laser cutting beam

3 cutting edge

4 laser structuring device

4a laser structuring beam

5 transport device

6 material application device

6a material beam

7 removal device

8 edition

10 cutting system

S1 Leading the objects to be cut

S2 cutting the objects

S3 Perform machining operations on the cut edges

S3a Structuring the cut edges

S3b Applying support materials to the cut edges

S4 Continue the cut objects

Claims

claims

Method for cutting sheet-like or plate-shaped objects (1), in particular of electrodes and / or separators for constructing an electrochemical energy store or of parts of such electrodes or separators, wherein the sheet-like or plate-shaped objects (1) comprise thermoplastic synthetic material fibers as support material and the cutting method comprises the steps of:

(51) advancing the objects to be cut (1) to a

Laser cutting device (2),

(52) cutting the objects (1) with the laser cutting device

(2) such that

a fusion of at least part of the thermoplastic polymer fibers is carried out at the cut edges (3).

2. The method according to claim 1, characterized in that the

thermoplastic synthetic fibers have a thermoplastic polyester, in particular polythylene terephthalate.

A method according to claim 1 or 2, characterized in that the step (S2) of cutting the objects (1) from the laser cutting device is carried out at least partially with a pulsed laser having at least one of the following characteristics:

a maximum wavelength in a wavelength range from 400 nm to 1300 nm, preferably a maximum wavelength of 1070 nm,

a pulse duration in a pulse duration range of 5 ps to 200 ns, preferably a pulse duration of 30 ns,

a frequency in a frequency range from 40 kHz to 5000 kHz, preferably from 250 kHz to 1000 kHz and a frequency of 500 kHz, an overlap of over 50%, preferably an overlap of over 90%

%

a beam quality <2 M ² ;

a power in a power range of 1 kW to 20 kW, preferably a power of 5 kW,

a Laserbrennfleckgröße smaller than 1000 μιτι, preferably a laser focal spot size smaller than 300 μιη.

Method according to one of claims 1 to 3, characterized in that the step (S2) of cutting the objects (1) of the laser cutting device with a cutting speed in a speed range of 0.01 m / s to 20 m / s, preferably in one Speed range from 0.05 m / s to 6.0 m / s and more preferably in a speed range of 0.5 m / s to 4.0 m / s is performed.

Method according to one of claims 1 to 4, characterized in that in the step (S2) of cutting the objects (1) the cut edges (3) of the objects (1) over a slot of a slotted support (8) rest.

Method according to one of claims 1 to 5, characterized in that in the step (S2) of cutting the objects (1) an ytterbium fiber laser is used.

Method according to one of claims 1 to 6, characterized in that the method comprises:

(S3) performing processing operations on the

Cutting edges (3), in particular a performing of Machining operations at the cutting edges (3) for

Reduction of micro-short circuits.

8. The method according to claim 7, characterized in that the step (S3) of performing machining operations on the cutting edges (3) for reducing micro-short circuits comprises:

(S3a) structuring the cut edges (3).

9. The method according to claim 8, characterized in that the step (S3a) of structuring the cut edges (3) with a laser structuring device (4) is performed.

10. The method according to claim 9, characterized in that the step (S3a) of structuring the cut edges (3) with the laser structuring device (4) after the step (S2) of cutting the object (1) with the laser cutting device (2) is carried out.

11. The method according to claim 9, characterized in that the step (S3a) of structuring the cut edges (3) with the laser structuring device (4) before the step (S2) of cutting the object (1) with the laser cutting device (2) is carried out.

12. The method according to claim 9 or 10, characterized in that for the step (S3a) of structuring the cut edges (3) as laser structuring device, the laser cutting device (2) of the step (S2) is used.

13. The method according to claim 9, characterized in that the step (S3a) of structuring the cut edges (3) with the laser structuring device (4) and the step (S2) of cutting the objects (1) with a laser cutting device (2) are carried out substantially simultaneously.

Method according to one of claims 7 to 13, characterized in that the step (S3) of performing machining operations on the cutting edges (3) for reducing micro-short-circuits comprises:

(S3b) applying support materials to the

Cut edges (3).

A method according to claim 14, characterized in that the step (S3b) of applying support materials to the cut edges (3) and the step (S2) of cutting the objects (1) with the laser cutting device (3) substantially simultaneously

be performed.

A method according to claim 14 or 15, characterized in that the support materials have components with increased absorption coefficients with respect to the wavelengths used by the laser cutting device (2).

System (10) for cutting thermoplastics fibers as carrier material having sheet- or plate-shaped objects (1), in particular for cutting electrodes and / or separators for the construction of an electrochemical energy store or parts of such electrodes or separators, wherein the cutting system (10) : - A transport device (5), which is designed for bringing the objects to be cut (1) to a laser cutting device (2), and

- A laser cutting device (2), to such a

Cutting the objects (1) is designed that

Cutting system (10) according to claim 17, characterized by:

- A processing device (4, 5), which is used for performing machining operations on the cut edges (3) for

Reduction of micro-short circuits is designed.

Cutting system (10) according to claim 18, characterized in that the processing device comprises a laser structuring device (4), which is designed for structuring the cut edges (3).

Cutting system (10) according to claim 18 or 19, characterized in that the processing device comprises a material application device (6) which is designed for the application of support materials to the cut edges (3).

Cutting system (10) according to one of Claims 17 to 20, characterized in that the laser cutting device (2) has an ytterbium fiber laser.

Battery, in particular a battery designed for use in motor vehicles, which has electrodes and / or separators to which a method according to one of Claims 1 to 16 has been applied and or which have been processed by a system according to any one of claims 17 to 21.