Multi-roll calender for producing electrode in dry coating method, assembly for laminating electrode path on both sides of metal foil, and method for producing electrode path using multi-roll calender

Abstract

The invention relates to a multi-roll calender for producing an electrode in a dry coating method, comprising a plurality of rolls arranged one after the other substantially along the main transport direction of the path of the electrode to be produced. A respective roller gap for the passage of the electrode path is formed between each pair of adjacent rollers running in opposite directions, wherein at least two adjacent rollers of the plurality of rollers are arranged such that their outer radii overlap in the main transport direction. The invention also relates to an assembly for laminating an electrode path on both sides of a metal foil comprising two multi-roll calenders, and to a method for producing an electrode path using a multi-roll calender.

Description

[0001] describe

[0002] The invention relates to a multi-roll calender for producing electrodes in a dry coating process, comprising a plurality of rollers which are arranged one behind the other essentially along the main conveying direction of the electrode path to be produced, wherein respective roller gaps for the passage of the electrode path are formed between adjacent rollers rotating in opposite directions.

[0003] Electrodes can be used in electrical energy storage batteries, which are widely used to power electronic devices, electromechanical devices, electrochemical devices and other useful devices. Such batteries include storage batteries, such as primary chemical batteries and secondary (rechargeable) batteries, fuel cells and various types of capacitors, including supercapacitors. Electrodes can also be used in water treatment plants. In particular, electric vehicles are developing rapidly. The energy source (i.e. the battery) in electric vehicles accounts for a large part of the cost. This is directly related to their production. Therefore, efficient and cost-effective production with increased energy density is required. In this regard, the calendaring process in the production process chain of lithium-ion battery cells is crucial.

[0004] Electrodes are key components of the storage potential of energy storage devices. The electromechanical capabilities of electrodes (e.g., the capacity and efficiency of battery electrodes) are determined by a variety of factors. These factors include, for example, but are not limited to, the distribution of the active material, binder, and one or more additives; the physical properties of the active material, binder, and additives, such as the particle size and surface area of ​​the active material; the surface properties of the active material; and the physical properties of the electrode film, such as the density, porosity, and cohesiveness of the film, as well as the adhesion of the film to the conductive element. These factors include the distribution of the active material, binder, and additives; the physical properties of the materials contained therein, such as the particle size and surface area of ​​the active material; the surface properties of the active material; and the physical properties of the electrode film, such as the density, porosity, cohesion, and adhesion to the conductive element. Dry processing systems and methods traditionally use high shear and / or high pressure processing steps to break up and mix the electrode film materials. Such systems and methods can offer structural advantages over wet-produced electrode films. However, the high processing pressures and large machine sizes (and therefore the required space) required to produce dry, self-supporting electrode films and dry electrodes leave room for improvement.

[0005] US 2020 / 0 227 722 A1 discloses a multi-roll calender for producing dry electrodes for energy storage devices. The system includes a first feed system for dry electrode material, a plurality of calendering rollers arranged one behind the other, and a control device. The calendering rollers are arranged so that a roller gap is formed between them. The first roller gap is provided to receive the dry electrode material from the first feed system for the dry electrode material and form a dry electrode film from the dry electrode material.

[0006] Multi-roll calenders known from the prior art have the following disadvantages: The calendering rollers are arranged linearly one behind the other in the main conveying direction. Consequently, due to the forces acting in the gap, one of the rollers forming the gap can become laterally deflected, resulting in inaccurate electrode path thickness or system vibration. This problem becomes more severe with the selected roller width. However, with the increasing demand for lithium-ion battery cells, it is necessary to use wider rollers, for example, to increase system productivity. Therefore, a solution to prevent this problem is needed.

[0007] The object of the present invention is therefore to improve a multi-roll calender such that it can achieve higher process stability and is designed to produce a more uniform electrode path. Thus, the multi-roll calender according to the invention enables a simplified, more economical electrode production method.

[0008] Therefore, it can be provided that at least two adjacent rollers of the plurality of rollers are arranged so that their outer radii overlap in the main conveying direction. This ensures that once the electrode path passes through the roller gap, the contact force required to guide it through the roller gap can be absorbed more specifically. This is achieved by overlapping the outer radii of the rollers in the main conveying direction, because the rollers are not linearly supported against each other, but are offset from each other. As a result, the supporting rollers can introduce a force component into the rollers forming the roller gap (through which the electrode path currently passes) that counteracts the direction in which the rollers forming the roller gap tend to deviate. Due to increasing material compaction, the forces in the roller gap increase, particularly from the inlet to the outlet, so that the rollers forming the roller gap tend to deviate accordingly, in particular against the conveying direction of the electrode path. The main conveying direction is the feed direction of the electrode path from one side of the multi-roll calender to the other and essentially corresponds to the direction in which the individual rollers of the calender are arranged adjacent to each other.

[0009] A multi-roll calender also has the advantage that the electrode path formed by the calender does not have to be self-supporting, as it can be positioned on and supported by the calender rolls during at least some, if not all, of the process steps. For example, if the electrode path is laminated to a metal foil to form an electrode, the electrode path can be supported by at least one calender roll during all process steps within the multi-roll calender system, including the lamination step.

[0010] The energy storage device produced using the multi-roll calender according to the present invention can have any suitable configuration, such as planar, spirally wound, button-shaped, toothed or bag-shaped. The energy storage device can be a component of a system, such as a power generation system, an uninterruptible power supply (UPS) system, a photovoltaic power generation system, an energy recovery system for, for example, industrial machinery and / or transportation. The energy storage device can be used to power various electronic devices and / or motor vehicles, including hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs) and / or electric vehicles (EVs).

[0011] It can also be provided that at least two adjacent overlapping rollers are arranged such that one roller is offset perpendicularly relative to the other roller with respect to the main conveying direction. The offset of one of the rollers relative to the zero line can be at least 1 mm, preferably 2 mm, and particularly preferably 2.5 mm. The offset of the other roller relative to the zero line can be at least 1 mm, preferably 2 mm, and particularly preferably 2.5 mm. The first roller and the second roller can be offset in opposite directions relative to the zero line.

[0012] Furthermore, at least two adjacent overlapping rollers can be arranged relative to one another such that the central axis of the front roller is located in front of the roller gap, relative to a direction transverse to the main conveying direction, while the central axis of the rear roller is located behind the roller gap, relative to the direction transverse to the main conveying direction, so that the electrode path guided through the roller gap is conveyed at least in a portion opposite to the main conveying direction. For example, if the main conveying direction is horizontal and the electrode path is conveyed substantially vertically downward through the roller gap, the central axis of the front roller is located vertically above the roller gap, while the central axis of the rear roller is located below the roller gap. Conversely, if the electrode path is conveyed substantially vertically upward through the roller gap, the central axis of the front roller is located vertically below the roller gap, while the central axis of the rear roller is located above the roller gap. The specific dimensions in front of and / or behind the roller gap can specifically refer to the feed direction of the electrode path through the respective roller gaps. In other words, the front and rear rollers forming the roller gap can have opposite directions of rotation, which define the direction in which the electrode path passes through the roller gap, with the central axis of the front roller being located in front of the roller gap, while the central axis of the rear roller is located behind the roller gap, relative to a direction substantially transverse to the main conveying direction.

[0013] The rollers of the multi-roll calender can each be arranged relative to one another such that the path of the electrode path between two adjacent roller gaps is in each case greater than 180° of the circumference of the respective roller.

[0014] It can be provided that all rollers are offset from the zero line and that their outer radii overlap relative to the main conveying direction. It can be provided that all rollers are arranged so that their outer radii overlap relative to the main conveying direction, and that all adjacent rollers are arranged relative to one another so that the center axis of each leading roller is located transversely to the main conveying direction, in front of the roller gap, and the center axis of each trailing roller is located transversely to the main conveying direction, in rear of the roller gap. For example, a multi-roll calender can have a third roller that forms a second roller gap between itself and a second roller, the second roller being arranged adjacent to and upstream of the third roller, wherein the second roller gap is designed to receive an electrode path guided around the second roller. The third roller can be arranged so that its outer radius relative to the main conveying direction overlaps that of the second roller, and the second and third rollers are arranged relative to one another so that the center axis of the second roller is located transversely to the main conveying direction, upstream of the second roller gap, and the center axis of the third roller is located transversely to the main conveying direction, downstream of the roller gap. Similarly, the calender can have a fourth, fifth, sixth, and / or seventh roller. Provision can be made for the gaps between the individual rollers to be individually controlled / adjustable. The multi-roll calender can also include one or more measuring devices, such as a gamma measuring device, for measuring the electrode path thickness or specific mass for thickness control / measurement. To this end, a control device can be provided that adjusts the size of the roller gap based on the measured electrode path thickness. The temperature of the individual rollers can also be controlled. For example, the temperature of the last roller of a multi-roll calender can be controlled to support lamination of the dry electrode foil onto the current collector or metal foil.

[0015] It is conceivable that all gaps have the same gap height. Furthermore, it can be provided that the height of at least one roller gap after the main conveying direction is smaller than the height of at least one roller gap arranged in front of it. It can be provided that the roller gap height decreases from the first to the last roller gap.

[0016] It can be provided that some of the roller gaps are arranged relative to one another in a common pressing plane. A multi-roll calender can have multiple rollers of the same diameter. These rollers can be arranged so that at least two gaps are formed between them (rollers of the same diameter). These roller gaps of roller pairs of the same diameter can lie in a common plane relative to the main conveying direction.

[0017] The multi-roll calender may have an inlet side for feeding the electrode precursor material and an outlet side for discharging the electrode path formed by the electrode precursor material.The electrode precursor material may be fed perpendicular to the main conveying direction.

[0018] It is conceivable that a roller gap is provided on the inlet side for receiving the supplied electrode precursor material, the roller gap being formed by two rollers whose diameters are smaller than the diameters of the other two rollers adjacent thereto. By using rollers with smaller diameters to supply the electrode precursor material (particularly material in powder form), the necessary high shear forces and / or high pressures can be generated in the roller gap to crush and mix the electrode precursor material. The rollers with smaller diameters can be offset in the same direction as the zero line. The offset of the front roller of the rollers relative to the zero line can be at least 3 mm, preferably at least 4 mm, and particularly preferably 4.45 mm. The offset of another of the rollers relative to the zero line can be at least 8 mm, preferably at least 9 mm, and particularly preferably 10 mm. Therefore, the offset between the two rollers can be at least 3 mm, preferably 4 mm, and particularly preferably at least 5 mm.

[0019] Provision can therefore be made that the rollers intended for receiving the electrode precursor material are at least two adjacent overlapping rollers.

[0020] The roller arranged in the main transport direction upstream of and adjacent to the roller provided for receiving the electrode precursor material may be a support roller which does not form a roller gap with the first roller of the rollers having the smaller diameter but is directly adjacent thereto.

[0021] The support roller can be positioned relative to the front roller of the rollers provided for receiving the electrode precursor material so that the center axis of the support roller is arranged behind the roller contact area formed between them with respect to the direction transverse to the main conveying direction, and the center axis of the front roller of the rollers provided for receiving the electrode precursor material is arranged in front of the roller contact area with respect to the direction transverse to the main conveying direction. Relative to the zero line, the support roller can be arranged opposite to a roller with a smaller diameter arranged behind the second roller (i.e., the fourth roller in this combination). The offset of the support roller relative to the zero line can be at least 1 mm, preferably 2 mm, and particularly preferably 2.5 mm. The support roller can be offset relative to the fourth roller by at least 2 mm, preferably 4 mm, and particularly preferably 5 mm.

[0022] It can be provided that at least two adjacent overlapping rollers are driven at different speeds. The speed, acceleration, rotation speed, etc. of each roller can be controlled individually.

[0023] The speed of the rear roller can be faster than that of the first roller. If the multi-roll calender has multiple rollers, the first roller can have the lowest speed, the second roller can have a higher speed than the first roller, the third roller can have a higher speed than the second roller, and so on. These different speeds can ensure shear within the film and / or generate forces that improve adhesion between the film and the faster-moving rollers.

[0024] It is conceivable that the roller gap of the rollers provided for receiving the electrode precursor material is associated with a feed device for supplying the electrode precursor material. The first roller gap can be designed so that it receives the electrode precursor material from the feed device and forms the electrode path from the electrode precursor material. The feed device can be a funnel-shaped feed hopper. The bulk material can be fed to the hopper by a suction or screw conveyor. The bulk material can be evenly distributed in the feed hopper and the material level can be kept constant during the feeding process. The formation of cavities and the decomposition of the material can be prevented by a special mixer. A rotating counter roller can be attached to the bottom side of the hopper. The unit size of the counter roller can be selected according to the particle size of the bulk material. The bulk material can be picked up by the counter roller and scraped off by a flexible scraper. The precisely measured bulk material can then be conveyed to the oscillating brush device. After the brush treatment process is completed, the bulk material can be inspected and transferred to the substrate line below.

[0025] The rollers can be fixed in position using play-free bearings. Tapered bearings or other bearing configurations can be used to secure the rollers without play, allowing for tight tolerances on the desired web thickness. It is conceivable that the rollers have the same diameter for each roller gap or for each roller within a roller gap. Alternatively, it is conceivable that the rollers have different diameters for each roller gap or for each roller within a roller gap. The surface of the rollers can be coated to increase surface hardness, for example with chrome or hard ceramic.

[0026] The present invention also relates to an assembly for laminating electrode paths on both sides of a metal foil, comprising two multi-roll calenders according to any of the preceding claims, the two multi-roll calenders being arranged so that the electrode paths formed therein are conveyed in opposite main conveying directions, wherein the downstream end rollers of the two multi-roll calenders form an end roller gap and rotate in opposite directions so that the metal foil fed into the end roller gap is coated on both sides by the corresponding electrode paths guided into the end roller gap.

[0027] It can be provided that the downstream end rollers are not offset with respect to one another, so that the laminated foil is guided through the end roller gap essentially perpendicularly to the main transport direction of the electrode path.

[0028] The assembly may further include a feed device disposed between the first and second multi-roll calenders, the feed device being configured to continuously feed metal foil into the end gap. The end gap may be designed to receive the metal foil and laminate one electrode path on one side of the metal foil and another electrode path on the other side of the metal foil. One electrode path may be a cathode path, while the other electrode path may be an anode path. The rollers forming the end gap may have one or more gap control actuators. The one or more gap control actuators may be configured to generate and control opposing forces between the first and second rollers forming the end gap during lamination. Provision may be made for the metal foil to be pre-coated with an adhesive before being fed into the end gap, or the adhesive may be applied to one side of the foil via a separate powder hopper on the multi-roll calender, allowing the foil to be laminated directly without the need for prior pre-coating of the material. After the lamination step, the assembly may include a cutting device to cut the laminated material strips into the final electrode width and roll them into individual electrode rolls.

[0029] The present invention also relates to a method for producing an electrode path using a multi-roll calender according to any one of claims 1 to 15 or an assembly according to any one of claims 16 to 17, the method comprising the following steps:

[0030] feeding the electrode precursor material into an inlet-side roll gap formed by an upstream roll and a downstream roll of a multi-roll press;

[0031] passing an electrode precursor material through an inlet-side gap to form an electrode path;

[0032] directing an electrode path around a downstream roller;

[0033] passing the electrode path through at least one additional roller gap;

[0034] removing the electrode path from the multi-roll calender;

[0035] Therein, when the electrode precursor material and / or the electrode path passes through the at least one roller gap, the transport direction of the electrode path has a movement component opposite to the main transport direction of the electrode path.

[0036] It may be provided that, in the method, the electrode path can be guided over more than 180° around the downstream roller.

[0037] In particular, provision can be made for the speed of the downstream roller to be greater than the speed of the upstream roller.

[0038] It may be provided that discharging the electrode path from the multi-roll calender comprises laminating the electrode path onto a metal foil.

[0039] It can be provided that the method comprises producing two electrode paths which are transported in opposite main transport directions, wherein the electrode paths are laminated onto both sides of the metal foil as they emerge from the respective multi-roll calender.

[0040] The method can be carried out prior to the process of preparing an electrode precursor material, which can be a powder. The process can start with the dry mixing of dry active material particles, dry conductive particles and dry binder particles to form a first dry mixture. In addition, dry conductive particles and dry binder particles can also be dry mixed to form a second dry mixture that can be supplied to a dry fiberization step. In the dry fiberization step, a jet mill can be used to fiberize the dry mixture. During the dry fiberization step, high shear forces are applied to the dry mixture to physically stretch it and form a thin mesh fiber network. In the dry feeding step, the first dry mixture and the second dry mixture formed respectively can be supplied to corresponding containers to form a dry film. The dry film can then be supplied to a multi-roll calender and compacted and calendered therein to obtain an embedded / mixed electrode path or a self-supporting electrode path. The electrode path is then connected to a current collector (such as a metal foil).

[0041] An advantage of the method is that the self-supporting electrode paths produced in this manner have improved properties relative to electrode paths produced using wet methods. For example, the dry electrode paths may have one or more of the following properties: improved material strip strength, improved cohesion, improved adhesion, improved electrical performance, or reduced defect occurrence. Defects may include holes, cracks, or surface depressions in the electrode paths. Adhesion may be adhesion to the current collector. Electrical performance is related to specific capacity. Material strip strength may be tensile strength.

[0042] Further details of the present invention are explained with reference to the following drawings. Specifically:

[0043] Figure 1 A schematic side view showing a roller assembly of a multi-roll calender according to the present invention Figure 2

[0044] Figure 2 A schematic side view showing the inlet side roll assembly of the multi-roll calender according to the present invention Figure 2

[0045] Figure 3 A side view showing an embodiment of an inlet side roll assembly of a multi-roll calender according to the present invention Figure 2

[0046] Figure 4 Shown is a side view of an embodiment of an assembly consisting of two counter-rotating multi-roll calenders.

[0047] Figure 1A side view of an exemplary embodiment of a roller assembly of a multi-roll calender 1 according to the present invention is shown. The assembly shown has a total of seven rollers 2 positioned adjacent to one another in a main conveying direction X, each offset relative to one another and relative to a zero line N or pressing plane P. The rollers 2 are offset relative to one another vertically and in the main conveying direction X, such that the outer radii Rw of the rollers 2 overlap in the main conveying direction X. The left half of the figure shows the inlet side 5 of the multi-roll calender 1. Therein, electrode precursor material 7 is fed from above via a feed device 9 (not shown) into the roller gap between the second and third rollers from the left (the smaller diameter D1 of these two rollers is smaller than the larger diameter D2 of the other rollers 2) and fed through the two rollers 2 of diameter D1 at a predetermined roller gap pressure. On the opposite side of the roller gap 3, a pressure-generated electrode path 4 is guided around the underside of the third roller 2 and fed into the second roller gap 3 shown in the figure between the third and fourth rollers 2, where the third roller has a diameter D1 and the fourth roller has a diameter D2. The electrode paths 4 are attached to the trailing rollers 2, with each downstream roller 2 rotating at a higher speed than the adjacent upstream roller 2. The higher speed of the downstream roller 2 causes shearing of the electrode paths 4 in the roller gap 3, causing them to adhere to the faster roller 2. The first roller 8 on the left side of the diagram does not convey the electrode paths 4. Instead, it supports the second roller 2, or the first roller with the smaller diameter D1. Therefore, there is no roller gap 3 between these two rollers; instead, the rollers 2 are in direct contact with each other. As shown in the diagram, adjacent rollers 2 rotate in opposite directions. In the example shown, the supporting roller 8 rotates counterclockwise, the second roller rotates clockwise, the third roller rotates counterclockwise again, and so on. The rollers 2, between which the electrode paths 4 pass in a zigzag pattern, are arranged relative to each other so that the center axis M of the preceding roller 2 forming the roller gap 3 is vertically positioned forward of the roller gap 3, and the center axis M of the following roller 2 is positioned behind the roller gap 3. For example, the second roller 2 rotates clockwise and the third roller rotates counterclockwise, so that the feed direction of the electrode path 4 through the roller gap 3 formed by the second roller and the third roller 2 is substantially vertically downward. Now, the center axis M of the second roller 2 is arranged above the roller gap 3, while the center axis M of the third roller 2 is arranged below the roller gap 3. In the adjacent gap 3 between the third roller and the fourth roller 2, the feed direction is substantially vertically upward, so that the center axis M of the third roller 2 is located below the roller gap 3, while the center axis M of the fourth roller 2 is located above the roller gap 3. This arrangement of the rollers 2 results in the movement direction B of the electrode path 4 having a vertical component B respectively. Y and the horizontal component B X , where the horizontal component B Xare each oriented relative to the main conveying direction X. The roller arrangement shown also has the following characteristics: the electrode path 4 in each case travels over a path greater than 180° of the arc of the respective roller. The electrode path leads out of the multi-roll calender 1 at the outlet side 6 .

[0048] Figure 2 The first four rollers 2 arranged on the inlet side are shown in detail again, wherein the central roller 2 forms a roller gap 3 for receiving the supplied electrode precursor material 7. For the sake of clarity, the offsets between the individual rollers 2 are shown greatly exaggerated relative to the roller diameter. The first roller or support roller 8 has an offset V relative to the zero line N. Y8 , which is located vertically below the zero line N. Relative to the zero line N, the second roller 2 has an offset V Y1 , which is also located vertically below the zero line N and is greater than the offset V of the first roller 8 Y8 With respect to the zero line N, the third roller 2 has an offset V Y2 , which is also located vertically below the zero line N and is greater than the offset V of the second roller 2 Y1 With respect to the zero line N, the third roller 2 has an offset V Y3 , which is located vertically above the zero line N and corresponds to the offset V of the first roller 8 Y8 In the example shown, the offset V Y8 2.5mm, offset V Y1 4.45mm, offset V Y2 is 10mm and offset V Y3 In the horizontal direction, that is, along the main conveying direction X, the second roller and the third roller have an overlapping portion V X1、2 , and the third roller and the fourth roller have an overlapping portion V X2、3 , the overlapping portion is larger than the overlapping portion V X1、2 With respect to the roll gap 3 between the second and third rolls, the second roll 2 represents the front roll 2.1, and the third roll 2 represents the rear roll 2.2. With respect to the roll gap 3 between the third and fourth rolls, the third roll 2 represents the front roll 2.1, and the fourth roll 2 represents the rear roll 2.2.

[0049] Figure 3 The first four rollers 2, arranged on the inlet side, are shown in their installed state to actual size. In particular, the figure shows the feed device 9, by means of which the powdered electrode precursor material 7 is fed into the roller gap 3 between the second and third rollers 2. The feed device 9 is arranged vertically above the roller gap 3 so that the electrode precursor material 7 is conveyed into the roller gap 3 by gravity. The rollers are each mounted independently of one another in the calender frame 14 and can be controlled independently of one another, particularly with respect to gap adjustment and the respective rotational speeds of the rollers 2.

[0050] Figure 4An assembly 2 for producing metal foil coated with electrodes on both sides is shown. Assembly 2 comprises two multi-roll calenders 1 connected end to end, with opposite main conveying directions X1, X2. Each multi-roll calender has eight rollers 2, of which the inlet-side end rollers are designed as support rollers 8, and the outlet-side end rollers form a common end roller gap 13. A metal foil 11 is fed vertically from above into the end roller gap 13. Both sides of the foil are coated through the electrode paths 4 generated in the two multi-roll calenders 1, so that the coated metal foil 11 exits the end roller gap 13 vertically downwards and can then be cut to length and / or rolled up or further processed.

[0051] The features of the invention disclosed in the above description, the drawings and the claims may be essential to the implementation of the invention both individually and in any combination.

[0052] Reference Signs List

[0053] 1 Multi-roll calender

[0054] 2 rollers

[0055] 2.1, 2.2 Overlapping rollers

[0056] 3 Roller Gap

[0057] 4-electrode path

[0058] 5 Inlet side

[0059] 6 Exit side

[0060] 7 Electrode Precursor Materials

[0061] 8 Support rollers

[0062] 9 Feeding device

[0063] 10 components

[0064] 11 metal foil

[0065] 12 end rollers

[0066] 13 End roller gap

[0067] 14 Calender frame

[0068] B Direction of movement in the roller gap

[0069] B x Component of movement relative to the main conveying direction

[0070] B Y Movement component perpendicular to the main conveying direction

[0071] D1 small diameter

[0072] D2 Large diameter

[0073] Center axis of M roller

[0074] N Neutral line

[0075] P Pressing plane

[0076] R W Outer radius

[0077] V Y8 Offset of the support rollers perpendicular to the main conveying direction

[0078] V Y1 Offset of the first roller perpendicular to the main conveying direction

[0079] V Y2 Offset of the second roller perpendicular to the main conveying direction

[0080] V Y3 Offset of the third roller perpendicular to the main conveying direction

[0081] V X1、2 Offset of the first and second rollers in the main conveying direction

[0082] V X2，3 Offset of the second and third rollers in the main conveying direction

[0083] X main conveying direction

Claims

1. A multi-roll calender (1) for producing electrodes by a dry coating process, It comprises a plurality of rollers (2) which are arranged one behind the other substantially along the main conveying direction (X) of the electrode path to be produced, wherein respective roller gaps (3) for the electrode path (4) to be passed through are formed between adjacent rollers (2) which respectively rotate in opposite directions and between adjacent rollers (2) which rotate in opposite directions, It is characterized in that At least two adjacent rollers of the plurality of rollers (2) are arranged so that their outer radii (R W ) overlap relative to the main conveying direction (X).

2. The multi-roll calender (1) according to claim 1, wherein the at least two adjacent overlapping rollers (2.1, 2.2) are arranged so that one of the rollers is vertically offset relative to the other roller with respect to the main conveying direction (X).

3. A multi-roll calender (1) according to claim 1 or 2, wherein the at least two adjacent overlapping rollers (2.1, 2.2) are arranged relative to each other so that the center axis (M) of the front roller (2.1) is arranged in front of the roller gap (3) relative to the direction transverse to the main conveying direction (X), and the center axis (M) of the rear roller (2.2) is arranged behind the roller gap (3) relative to the direction transverse to the main conveying direction (X), so that the electrode path (4) guided through the roller gap (3) is at least partially conveyed opposite to the main conveying direction (X).

4. The multi-roll calender (1) according to any one of claims 1 to 3, wherein the path of the electrode path (4) between two adjacent roller gaps (3) is respectively greater than 180° of the circumference of the corresponding roller (2).

5. The multi-roll calender (1) according to claim 4, wherein all rollers (2) are arranged so that their outer radius (R W ) overlap with respect to the main conveying direction (X), and all adjacent rollers (2) are arranged relative to each other so that the center axis (M) of the corresponding front roller (2.1) is located in front of the roller gap (3) with respect to the direction transverse to the main conveying direction (X), and the center axis (M) of the corresponding rear roller (2.2) is arranged behind the roller gap (3) with respect to the direction transverse to the main conveying direction (X).

6. The multi-roll calender (1) according to any one of the preceding claims, wherein all gaps (3) have the same gap height.

7. The multi-roll calender (1) according to any one of claims 1 to 5, wherein the height of at least one rear gap (3) in the main conveying direction (X) is smaller than the height of at least one gap arranged in front of it.

8. The multi-roll calender (1) according to any of the preceding claims, wherein at least some of the roll gaps (3) are arranged relative to one another in a common pressing plane (P).

9. A multi-roll calender (1) according to any of the preceding claims, wherein the multi-roll calender (1) has an inlet side (5) for supplying electrode precursor material (7), and wherein the multi-roll calender (1) has an outlet side (6) for discharging the electrode path (4) formed by the electrode precursor material (7).

10. A multi-roll calender (1) according to claim 9, wherein an inlet-side roller gap (3) is provided for receiving the supplied electrode precursor material (7), and the inlet-side roller gap is formed by two rollers (2), and the diameters (D1) of the two rollers are smaller than the two other rollers (2) respectively adjacent thereto.

11. Multi-roll calender (1) according to claim 10, wherein the rollers (2) provided for receiving the electrode precursor material (7) are the at least two adjacent overlapping rollers (2.1, 2.2).

12. A multi-roll calender (1) according to any one of claims 10 or 11, wherein the roller arranged in front of and adjacent to the roller (2) provided for receiving the electrode precursor material (7) in the main conveying direction (x) is a support roller (8), which does not form a roller gap with the first of the rollers (2) with a smaller diameter (D1), but is directly adjacent to it.

13. A multi-roll calender (1) according to claim 12, wherein the support roller (8) is arranged relative to the front roller of the roller (2) provided for receiving the electrode precursor material (7) so that the center axis (M) of the support roller (8) is arranged behind the roller contact area formed therebetween with respect to the direction transverse to the main conveying direction (X), and the center axis (M) of the front roller of the roller (2) provided for receiving the electrode precursor material (7) is arranged in front of the roller contact area with respect to the direction transverse to the main conveying direction (X).

14. The multi-roll calender (1) according to any one of the preceding claims, wherein the at least two adjacent overlapping rollers (2.1, 2.2) are driven at different rotational speeds.

15. A multi-roll calender (1) according to any one of claims 10 to 14, wherein a feed device (9) for supplying the electrode precursor material (7) is associated with the roller gap (3) of the rollers provided for receiving the electrode precursor material (7).

16. A component (10) for laminating electrode paths (4) on both sides of a metal foil (11), comprising two multi-roll calenders (1) according to any one of the preceding claims, wherein the two multi-roll calenders are arranged so that the electrode paths (4) formed therein are respectively supplied along opposite main conveying directions (X), wherein the downstream end rollers (12) of the two multi-roll calenders (1) form an end roller gap (13) and rotate in opposite directions, so that the metal foil (11) supplied to the end roller gap (13) is coated on both sides by the electrode paths (4) respectively guided into the end roller gap (13).

17. An assembly (10) according to claim 16, wherein the downstream end rollers (12) are not offset with respect to each other so that the laminated metal foil (11) is guided through the end roller gap (13) essentially perpendicular to the main conveying direction (X) of the electrode path (4).

18. A method for producing an electrode path (4) using a multi-roll calender (1) according to any one of claims 1 to 15 or an assembly (10) according to any one of claims 16 to 17, the method comprising the following steps: Supplying an electrode precursor material (7) into an inlet-side roll gap (3) formed by an upstream roll and a downstream roll (2) of the multi-roll press (1); Passing the electrode precursor material (7) through the inlet-side roller gap (3) and thereby forming an electrode path (4); guiding the electrode path (4) around the downstream roller (2); Passing the electrode path (4) through at least one further roller gap (3); Discharging the electrode path (4) from the multi-roll calender (1); When the electrode precursor material (7) and / or the electrode path (4) passes through the at least one roller gap (3), the conveying direction of the electrode path (4) has a movement component opposite to the main conveying direction (X) of the electrode path (4).

19. Method according to claim 18, wherein the electrode path (4) is guided over more than 180° around the downstream roller (2).

20. The method according to claim 18 or 19, wherein the rotation speed of the downstream roller (2) is greater than the rotation speed of the upstream roller (2).

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