Device and method for producing individual electrode sheets for an energy cell from an electrode sheet material

Abstract

The invention relates to a device (10) for producing individual electrode sheets (11) for an energy cell, in particular a battery cell, from an electrode sheet material (12). The device (10) comprises a cross cutting device (13) which is designed for separating the electrode sheet material (12) into individual electrode sheets (11) by creating cross cuts (14), and a contour cutting device (15) which is designed for performing contour cuts (16) on at least one longitudinal edge (17, 18) and / or at least one transverse edge (19, 20) of the individual electrode sheets (11). The invention also relates to a corresponding method.

Description

[0001] Device and method for producing individual electrode sheets for an energy cell from an electrode track

[0002] The present invention relates to a device for producing individual electrode sheets for an energy cell, in particular a battery cell, from an electrode web according to the preamble of claim 1 and to a corresponding method according to the preamble of claim 12.

[0003] Energy cells or energy storage devices within the meaning of the invention are used, for example, in motor vehicles, other land vehicles, ships, aircraft or even in stationary storage systems in the form of battery cells or fuel cells, in which very large amounts of energy must be stored over longer periods of time.

[0004] Providing a sufficient quantity of energy cells, especially battery cells, requires mass-market manufacturing technologies with high production speeds. Among other things, the assembly of electrode sheets into finished cell stacks, energy cells, or battery cells presents a challenge. Separation processes are particularly important in the production of individual electrode sheets from electrode sheets for a stacked arrangement. Such separation processes are subject to stringent requirements in order to achieve the production speed required for mass production while maintaining the highest possible product quality.Against this background, the object of the invention is to provide a device for producing individual electrode sheets for an energy cell, in particular for a battery, from an electrode web, which enables the highest possible production speed with sufficient quality and accuracy.

[0005] To achieve this objective, a device for producing individual electrode sheets for an energy cell, in particular a battery cell, from an electrode sheet is proposed. The device comprises a cross-cutting device configured to separate the electrode sheet into individual electrode sheets by creating cross-sections, and a contour cutting device configured to perform contour cuts on at least one longitudinal edge and / or at least one transverse edge of the electrode sheets. Cross-sections can be created in the form of cuts made transversely to the longitudinal extent of the electrode sheet.

[0006] The electrode web is preferably a conductive electrode foil made of metal, which is further preferably largely coated with an active anode or cathode material. Furthermore, the anode or cathode material is preferably already calendered on the electrode foil, so that the electrode sheets separated from the electrode web can then be fed into a process for forming an energy cell or battery. The electrode web is conveyed in a conveying direction and is preferably endless. The cross-cutting device separates the intended electrode sheets from the electrode web through the cross section, which are then preferably conveyed further in a continuous product stream in the conveying direction. The cross-sections and / or contour cuts can lead through coated and uncoated material.

[0007] When the contour cutting device makes a contour cut on one or both longitudinal edges and / or one or both transverse edges, it is possible, for example, to form a connection tab (tab) for making electrical contact. Furthermore, rounded corners or so-called shoulders on the electrode blades can also be formed by the contour cuts. The contour cuts have a longitudinal cut component, i.e. along the conveying direction parallel to the course of the electrode path, and a cross-sectional component which accordingly runs perpendicular to the conveying direction. The contour cuts can therefore run, for example, entirely or in sections at an angle to the conveying direction, for example 45° to the conveying direction. Furthermore, the contour cuts can, for example, have a curved course, for example entirely or in sections.Furthermore, the contour cuts, which are composed of longitudinal and cross-sectional components, can have exclusively longitudinal or cross-sectional components in certain sections; for example, at the end of a conductor lug, a section in the contour cut can have a purely longitudinal component. The contour cuts produced can in particular also be referred to as notching. The longitudinal edges of the electrode sheets run parallel to the conveying direction and to the product flow. The contour cut is preferably made on at least one longitudinal edge. The transverse edges of the electrode sheets run perpendicular to the conveying direction. In particular, when rounding the corners of the individual electrode sheets by a contour cut, the contour cut can be provided on both a longitudinal edge and a transverse edge. In possible embodiments, a contour cut is made on at least one transverse edge.

[0008] The proposed device allows for significantly higher tolerance in cutting positions, which is achieved in particular through the sequence of the cutting processes. Accordingly, the cross-cutting and separation into electrode sheets are performed first, and only then is the contour cutting performed to form, for example, conductor tabs and fillets. It is therefore preferred that the contour cutting device be arranged downstream of the cross-cutting device in the product flow of the electrode web and / or electrode sheets.

[0009] This makes it possible to avoid, in particular, critical cutting errors that could lead to the rejection of the electrode sheet or, during further processing, to premature failure of the energy cell or battery. A critical cutting error can, for example, be that a predefined cutting edge for the cross-section is not met precisely in relation to the contour cut already made in the prior art. This can, particularly in the case of rounded corners or shoulders in the run-out area of ​​the radii, form needle-like webs that can easily pierce a separator film in an energy cell or a battery cell and render the cell unusable. Such an error pattern can therefore be avoided in a process-stable manner using the proposed device. Furthermore, complex measures for maintaining tolerances can be dispensed with. This particularly applies to the width tolerance of an electrode sheet, i.e.the dimensional accuracy of the extension of electrode sheets in the conveying direction. The width tolerance can advantageously correspond to the manufacturing tolerance of the cross-cutting device, for example, a cutting or knife roller, since cutting occurs directly from the electrode sheet without having to consider an adjustment to an existing contour cut on the longitudinal edges of the electrode sheet. Thus, a very small width tolerance for the electrode sheets can be achieved.

[0010] In a preferred embodiment, the contour cutting device is configured to create a conductor tab. Therefore, the separated electrode sheets are fed to the contour cutting device, and the conductor tabs are formed on the separated electrode sheets.

[0011] Preferably, the contour cutting device is configured to create a rounded portion of at least one corner of the electrode sheets. The rounding of at least one corner, preferably all four corners in the case of a rectangular starting surface of the electrode sheet, is thus performed on the separated electrode sheet, thereby preventing the formation of needle-like ridges, particularly where the radii of the rounded portion extend to the transverse edge. Needle-like ridges can, for example, pierce a pouch casing and thereby destroy the respective energy cell or battery cell.

[0012] According to a further development, it is proposed that the contour cutting device be configured to create the rounding of at least one corner with radii that do not taper tangentially into the longitudinal edges and / or transverse edges of the respective electrode sheet. This makes it possible to avoid critical cutting errors by ensuring a greater tolerance of the respective cutting positions.

[0013] The transition from the radius of a fillet to a longitudinal or transverse edge preferably encloses an angle other than 180°. The transition can, for example, have an angle in the range of 179° to 150°, or further, for example, 170° to 160°. A corner fillet can generally have a constant or varying radius over its entire length.

[0014] According to a further development, it is further proposed that the device comprises a spacing device which is arranged between the cross-cutting device and the contour-cutting device and is designed to provide the individual electrode blades in the product flow with a spacing from one another.

[0015] The spacing device increases the distance between the individual electrode sheets in the product stream, so that the minimum distance or the gap between two electrode sheets resulting from the cross-section is increased. The increased distance between two electrode sheets is preferably between two opposite transverse edges of the respective electrode sheets. The increased distance can, for example, be in a range of 1 mm to 10 mm. In advantageous embodiments, the spacing device can be a drum with radially movable segments which move the electrode sheets to a larger circumference of the drum before being discharged. Due to the generated distance between the electrode sheets in the product stream, the contour cut or the contour cuts can be carried out particularly easily by the contour cutting device with comparatively large tolerances of the cutting position.This applies in particular to the rounding of corners at the transition from a longitudinal edge to a transverse edge. In advantageous embodiments, the contour cutting device comprises a knife roller. The knife roller of the contour cutting device can, for example, be configured for contour cutting together with a counter-drum on which the electrode sheets are conveyed individually, preferably at a distance from one another. The contour cutting device is preferably configured for a contour cut that has a linear contact during cutting or also a squeezing cut in the sense that a section of a line or contour is cut simultaneously. Therefore, the contour cut is preferably not a scissor cut with a point-like cutting contact.With such a line cut, the usually complex contour cuts with longitudinal and transverse components can be produced, particularly in a continuous process in the product stream.

[0016] According to a further development, it is proposed that the contour cutting device comprise a laser cutter. The laser cutter preferably has a laser scanner or another unit for beam steering, so that any desired geometry of the contour cuts on the longitudinal edges and / or transverse edges of the electrode sheets is possible. Furthermore, very good quality cut edges can be achieved with the laser cutter; particularly with complex contour cuts, a higher quality of the cut edges can be achieved with the laser cutter compared to a knife. The laser cutter preferably cuts the contour cuts on a drum or a counter drum or even a suction drum, which feeds the separated electrode sheets, preferably continuously.A laser cutter is particularly suitable for performing contour cuts in the contour cutting device because it avoids the high cutting forces required for contour cutting, which generally do not allow for point-like cutting contact. Furthermore, the laser cutter allows for highly variable contour cuts with good cut quality. Furthermore, there is a high degree of variability regarding the length of the electrode sheets between the two transverse edges, so that, for example, contour cuts can also be produced for electrode sheets intended for a wound or folded energy cell, in particular a battery cell. Furthermore, the laser cutter can be used to produce a contour cut of largely any shape for a comparatively long longitudinal edge, whereby the contour cut does not need to have any repeating geometries or patterns.

[0017] In an advantageous embodiment, the cross-cutting device comprises a knife roller. The cross-cutting device preferably further comprises a suction roller for holding the electrode web and / or for the individual electrode sheets separated from the electrode web, as a counter-drum to the knife roller. The knife roller and the suction roller or counter-roller are preferably arranged such that a gap exists between a circumferential surface of the knife roller and a circumferential surface of the counter-roller, in which gap the electrode web is guided. Radially projecting cutting knives are preferably arranged on the knife roller. A counter-knife is provided on the counter-roller or corresponding suction roller. In advantageous embodiments, the cross-cutting device has a point-shaped cutting contact during the cross-section, analogous to a scissors cut.This allows a cross-section to be produced with low cutting forces and good quality cutting edges.

[0018] In an alternative embodiment, the cross-cutting device comprises a laser cutter. The laser cutter of the cross-cutting device preferably has a laser scanner, for example, a galvanometer scanner or a polygon scanner, or another unit for beam steering, so that the cross-sections can be produced in a continuous product stream, for example, when the laser is arranged outside a drum, in particular a suction drum, on which the electrode web and / or the electrode sheets can be conveyed. Good quality cut edges on the cross-sections can be achieved with the laser cutter.

[0019] According to a further development, it is proposed that the device comprise an ejection device between the cross-cutting device and the contour-cutting device. This allows defective electrode sheets to be ejected before further processing steps. For example, defective areas in the electrode web may already have been detected before separation, so that these defective sections are ejected from the manufacturing process of an energy cell or battery cell, e.g., a lithium-ion battery, as early as possible after separation by the cross-cutting device.

[0020] The proposed device conveys and produces the electrode sheets from the electrode web, preferably in a continuous drum process, wherein various types of drums can be provided for receiving, dispensing, and processing the electrode web into electrode sheets. The produced electrode sheets can then be removed from the device and fed to a laying-up, stacking, or rolling process for further processing into an energy cell or battery, in particular a lithium-ion battery. To achieve the object, a method for producing individual electrode sheets for an energy cell, in particular a battery cell, from an electrode web using a device according to one of claims 1 to 11 is further proposed.

[0021] The invention will be explained below using preferred embodiments with reference to the attached figures.

[0022] Fig. 1 is a schematic representation of an apparatus for producing individual electrode sheets from an electrode web;

[0023] Fig. 2 is a schematic representation of the production of individual electrode sheets from an electrode web;

[0024] Fig. 3 is a detailed view of a typical defect pattern on an electrode sheet in the prior art;

[0025] Fig. 4 is a detailed view of electrode blades and a contour cutting device;

[0026] Fig. 5 is a schematic representation of another device for producing individual electrode sheets from an electrode web with an ejection device;

[0027] Fig. 6 is a schematic representation of another device for producing individual electrode sheets from an electrode web, with a laser cutter in the contour cutting device; Fig. 7 is a schematic representation of another device for producing individual electrode sheets from an electrode web, with a laser cutter in the contour cutting device and in the cross-cutting device; and

[0028] Fig. 8 is a schematic representation of another device for producing individual electrode sheets from an electrode web with an ejection device and a laser cutter in the contour cutting device.

[0029] Figure 1 schematically shows an embodiment of a device 10 for producing individual electrode sheets 11 from an electrode web 12. The electrode web 12 is a conductor foil coated with anode or cathode material, wherein the coating is recessed, for example, in a strip along a longitudinal edge 18 (see also Figure 2). The electrode web 12 is fed to the device 10 according to the symbolic arrow and cut into individual electrode sheets 12 by cross sections 14 in a cross-cutting device 13. In this embodiment, the cross-cutting device 13 has a knife roller 27 which engages a suction roller 31 or counter-roller and cuts electrode sheets 11 by cross sections 14 perpendicular to the conveying direction. The electrode sheets 11 are held on the suction roller 31 by means of negative pressure and have a gap between them at the resulting transverse edges 19, 20.

[0030] In this exemplary embodiment, the electrode sheets 11 are then transferred to a spacing device 23, which is arranged between the cross-cutting device 13 and the contour cutting device 15 in the device 10. The spacing device 23 is, for example, a drum with radially retractable segments, so that the electrode sheets 11 are raised to a larger circumference and have an increased distance 24 from one another upon transfer to the further suction roller or counter-drum 32, which simplifies further processing and, in particular, the production of contour cuts 16.

[0031] In this embodiment, the suction roller 32 or the counter roller is part of the contour cutting device 15. The knife roller 28 engages in the contour of the suction roller 32 or counter roller and forms at least one contour cut 16 on the electrode sheets 11. The electrode sheets 11 are then conveyed out of the device 10 and fed, for example, to a stacking process to form a battery with further electrode sheets 11 with anode or cathode material and separators.

[0032] Figure 2 shows the production sequence in the device 10 for the electrode web 12 and the electrode sheets 11. The electrode web 12 is fed into the device 10 from the left. In the cross-cutting device 13, an electrode sheet 12 is severed from the preferably endless electrode web 12 by a cross-section 14. Subsequently, in this advantageous illustration, the electrode sheets 11 are spaced apart at the transverse edges 19, 20, so that an increased distance 24 is established between the individual electrode sheets 11. In alternative embodiments, spacing can be omitted. Furthermore, the production of contour cuts 16 by the contour cutting device 15 is illustrated on the right-hand side of Figure 2.At the lower longitudinal edge 17, a rounding 26 of the corners 22 is carried out, while at the upper longitudinal edge 18 a strip of the electrode track 12 is uncoated and next to the rounding 26 of the corners 22 a conductor lug 21 for the electrical contact is cut into the uncoated strip.

[0033] Figure 3 shows a detailed view of a typical defect pattern in the production of electrode blades 11 in the prior art, in which notches are initially made on the longitudinal edges 17 by a contour cut 16. At the transition from the contour cut 16 on an edge 17 to a cross-section 14, it can happen that a cross-cutting device 13 is not optimally adjusted and, as a result, the cross-section 14 does not run exactly through the intersection points of the radii of the fillets 26 of the contour cut 16. Ideally, with this exemplary geometry of the electrode blades 11, the cross-section 14 runs through the tapered region. As schematically shown on the left in Figure 3, the cross-section 14 does not lie on the intended dividing line, which connects the tapered regions of the two opposite fillets 26, which are still connected in this state. The cross-section 14 therefore does not run through the two tapered regions.In Figure 3 on the right, after additional spacing of the two electrode blades 11, it can be seen that the tolerance-dependent cutting position of the cross-section 14 creates a sharp-edged strip which, when used in an energy cell or battery cell, can, for example, damage the separator film and render the entire cell unusable. Such defect patterns, as in Figure 3, can be avoided in particular by the proposed device 10, as shown schematically in the embodiment in Figure 1, and the proposed method. The procedure using the proposed device 10 is shown in Figure 4 in two detailed views with electrode blades 11 and a cross-cutting device 13 (see left-hand illustration), and a contour cutting device 15 (see right-hand illustration). Here, too, there is a deviation of the cutting position of the cross-section 14 from the intended cutting position (dash-dotted line).However, since the rounding 26 of the corners 22 only occurs after the electrode sheets 11 have been separated, the contour cutting device 15 can extend with the cutting edge for the contour cut 16 beyond the radius of the rounding 26 in the longitudinal edge 17 and / or the transverse edges 19, 20. Thus, no needle-like web can form. Furthermore, the formation of secondary corners at the transition of the cutting edge at the tool outlet can also be avoided. This can be further improved by increasing the distance 24 between the two opposite transverse edges 19, 20, which is made possible by the spacing device 23 between the transverse cutting device 13 and the contour cutting device 15. Overall, the production of the roundings 26 by the contour cut 16 can be carried out with significantly larger tolerances. The formation of a pointed strip, as in Figure 3, can thus be easily avoided.Nevertheless, defective electrode sheets 11 can be ejected from the product stream after the cross-section 14.

[0034] In Figure 5, an ejection device 25 is additionally provided in the device 10, which in this embodiment is arranged after the spacing device 23 and before the contour cutting device 15 in the product flow of the electrode sheets 11. The device 10 can, for example, have a corresponding sensor system for detecting defective areas in the electrode track 12 and / or the electrode sheets 11, or, for example, receive data about defective areas in the electrode track 12 from an upstream sensor system. The defective areas or areas can thus be ejected from the product flow by the ejection device 25 directly after separation by the cross-cutting device 13, before further processing steps are carried out. Spacing by the spacing device 23 before the ejection device 25 allows for simplified ejection of individual electrode sheets.

[0035] 11 from the product stream.

[0036] A further advantageous embodiment of a device 10 for producing electrode sheets 11 from an electrode web

[0037] 12 is shown schematically in Figure 6. The structure of the embodiment in Figure 6 is analogous to the embodiment in Figure 1, wherein the contour cutting device 15 comprises a laser cutter 30 instead of a measuring roller 28. By means of the laser cutter 30, the contour cuts 16 on the electrode sheets 11 can be carried out very precisely and individually or variably. The electrode sheets 11 are fixed to the suction roller 32 by means of negative pressure, while the laser cutter 30 carries out the contour cut 16 on the electrode sheets 11, which are continuously conveyed on the suction roller 32, which can also be referred to as a counter roller or drum.

[0038] The embodiment shown schematically in Figure 7 has, in addition to the laser cutter 30 in the contour cutting device 15 corresponding to the embodiment of Figure 6, a further laser cutter 29 in the cross-cutting device 13 for creating cross-sections 14. Therefore, in this embodiment, both the cross-sections 14 and the contour cuts 16 can be performed with a laser cutter 29, 30 each.

[0039] Figure 8 shows a further schematic embodiment which, like the embodiment of Figure 5, has an ejection device 25 for ejecting, for example, defective electrode sheets 11. Unlike the embodiment of Figure 5, the embodiment of Figure 8 has a laser cutter 30 in the contour cutting device 15, which serves to form the contour cuts 16. In a further possible embodiment, which is not shown, the cross-cutting device 13 can, unlike the illustration in Figure 8, also include a laser cutter 29 for creating cross-sections 14.

[0040] List of reference symbols

[0041] 10 Device

[0042] 11 Electrode sheet

[0043] 12 Electrode track

[0044] 13 Cross cutting device

[0045] 14 Cross section

[0046] 15 Contour cutting device

[0047] 16 Contour cut

[0048] 17, 18 Longitudinal edge

[0049] 19, 20 transverse edge

[0050] 21 Conductor lug

[0051] 22 Corner

[0052] 23 spacing device

[0053] 24 distance

[0054] 25 Ejection device

[0055] 26 Rounding

[0056] 27, 28 knife roller

[0057] 29, 30 Laser cutters

[0058] 31 suction roller

Claims

Claims:

1. Device (10) for producing individual electrode sheets (11) for an energy cell, in particular a battery cell, from an electrode array (12), characterized in that - the device (10) has a transverse cutting device (13) which is set up to separate the electrode path (12) into individual electrode sheets (11) by creating cross-sections (14), and - a contour cutting device (15) which is designed to perform contour cuts (16) on at least one longitudinal edge (17, 18) and / or at least one transverse edge (19, 20) of the electrode sheets (11).

2. Device (10) according to claim 1 , characterized in that the contour cutting device (15) is arranged behind the transverse cutting device (13) in the product flow of the electrode path (12) and / or electrode sheets (11).

3. Device (10) according to claim 1 or 2, characterized in that the contour cutting device (15) is configured to create a deflector flag (21).

4. Device (10) according to one of the preceding claims, characterized in that the contour cutting device (15) is configured to create a rounding (26) of at least one corner (22) of the electrode sheets (11).

5. Device (10) according to claim 4, characterized in that the contour cutting device (15) is used to create the Rounding (26) of at least one corner (22) is provided with radii that do not extend tangentially into the longitudinal edges (17, 18) and / or transverse edges (19, 20) of the respective electrode sheet (11).

6. Device (10) according to one of the preceding claims, characterized in that the device (10) has a spacing device (23) which is arranged between the transverse cutting device (13) and the contour cutting device (15) and is configured to provide the individual electrode blades (11) in the product stream with a distance (24) from each other.

7. Device (10) according to one of the preceding claims, characterized in that the contour cutting device (15) comprises a knife roller (28).

8. Device (10) according to one of the preceding claims, characterized in that the contour cutting device (15) comprises a laser cutter (30).

9. Device (10) according to one of the preceding claims, characterized in that the transverse cutting device (13) comprises a knife roller (27).

10. Device (10) according to one of the preceding claims, characterized in that the transverse cutting device (13) comprises a laser cutter (29).

11. Device (10) according to one of the preceding claims, characterized in that the device (10) is located between The cross-cutting device (13) and the contour cutting device (15) comprise an ejection device (25). A method for producing individual electrode sheets (11) for an energy cell, in particular a battery cell, from an electrode array (12) with a device (10) according to any one of claims 1 to 11.

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