Calendar for producing electrode films from powder-type electrode precursor materials, corresponding method, and corresponding electrode film

Abstract

The invention relates to a calendar for producing an electrode film from a powdered electrode precursor material, comprising at least a first nip roll and at least a second nip roll rotating in the opposite direction to the first nip roll and forming a nip between them, the calendar being designed to subject the powdered electrode precursor material to a shear force as it passes through the nip and thus form an electrode film, characterized in that at least one of the first nip roll or the second nip roll comprises at least one pretension device for pretensioning the nip roll against a non-axial, in particular radial and / or tangential, force vector acting on the respective nip roll, which is generated in the nip by a compression method, and by means of which it is possible to adjust the direction of pretension and / or the magnitude of the pretension. The invention further relates to a method for producing an electrode film with a uniform thickness from a powdered electrode precursor material and to a corresponding electrode film.

Description

[Technical field]

[0001] The present invention is based on a calendar for producing an electrode film from a powdered electrode precursor material, which comprises at least one first nip roll and at least one second nip roll rotating in the opposite direction to the first nip roll and forming a nip therebetween, the calendar being designed to subject the powdered electrode precursor material to a shear force as it passes through the nip, thereby forming an electrode film.

[0002] The electrodes can be used in electrical energy storage cells, which are widely used to power electronic, electromechanical, electrochemical and other useful devices. Such cells include batteries, such as primary chemical cells and secondary (rechargeable) cells, fuel cells and various types of capacitors, including ultracapacitors. The electrodes can also be used in water treatment plants. Electric mobility in particular is clearly growing. The battery, which is the energy source for electric vehicles, represents a large part of the cost. This is directly related to the production of electric vehicles. This requires an efficient and cost-effective production, while at the same time increasing the energy density. For this reason, calendaring methods are crucial within the process chain for manufacturing batteries, such as lithium-ion batteries.

[0003] A key component for the storage capacity of an energy storage system is the electrode. The electrochemical capabilities of the electrode, such as the capacity and efficiency of a battery electrode, depend on a variety of factors. These include the distribution of active materials, binders, and additives, the physical properties of the materials contained therein (such as particle size and surface area of ​​the active materials), the surface properties of the active materials, and the physical properties of the electrode film (such as density, porosity, cohesion, and adhesion to conductive elements). Dry processing systems and methods traditionally use high shear and / or high pressure processing steps to break down and mix the electrode film materials. Such systems and methods may contribute structural advantages over wet-fabricated electrode films. However, the production of dry free-standing electrode films and dry electrodes requires high processing pressures and large system dimensions (and therefore large space requirements), leaving room for improvement.

[0004] A multi-roll calender for manufacturing dry electrodes for energy storage devices is known from document US 2020 / 0 227 722 A1. The system comprises a first supply system for dry electrode material, a plurality of calender rolls arranged in succession, and a controller. The calender rolls are arranged such that a gap is formed between each of them. A first nip is provided to receive the dry electrode material from the first dry electrode material supply system and to form a dry electrode film from the dry electrode material.

[0005] Multi-roll calenders known from the prior art have the drawback that the forces acting on the nip can cause the calender rolls to move laterally, leading to inaccuracies in the thickness of the electrode film produced or vibrations in the system. The larger the roll width and the smaller the roll diameter chosen, the greater the problem. However, as the demand for lithium-ion batteries increases, it is necessary, inter alia, to use wider rolls and possibly smaller diameter rolls in order to increase the productivity of the system and improve the quality of the electrodes. A solution is therefore needed that prevents the above problems.

[0006] It is therefore an object of the present invention to improve the calender in such a way that it allows for greater process stability and is designed to produce more uniform electrode films, so that the calender according to the invention allows for a simplified and more cost-effective method for producing electrodes.

[0007] This object is achieved by a device, a method or an electrode film having the features of each of the independent claims.

[0008] To this end, it is provided that at least one of the first nip roll or the second nip roll has at least one pretensioning device for pretensioning the nip roll against non-axial, in particular radial and / or tangential, force vectors generated in the nip by the compression process and acting on the respective nip roll, and that the direction of pretension and / or the magnitude of the pretension are adjustable by means of the pretensioning device.

[0009] The calender according to the invention has the advantage, inter alia, that the electrode web formed by the calender does not need to be free-standing, since it can be positioned and supported on the calender rolls during at least some, but not all, process steps. For example, the electrode web can be supported by at least one calender roll during all process steps in a multi-roll calender system, including the lamination step in which the electrode web is laminated onto a metal foil to form an electrode.

[0010] Energy storage devices manufactured with the aid of the calendar according to the invention can have any suitable configuration, e.g., planar, spiral wound, button, toothed, or pouch shaped. The energy storage devices can be components of systems such as, for example, power generation systems, uninterruptible power supply systems (UPS), solar power systems, energy recovery systems used, e.g., in industrial machinery and / or transportation. The energy storage devices 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 may be provided that both nip rolls are mounted in the machine frame via their respective front roll journals, and that a pretensioning device is assigned to at least one bearing of the first nip roll or the second nip roll, by means of which the roll journal can be radially deflected in any direction and with an adjustable magnitude relative to the at least one bearing. The nip rolls may each have a central calendaring section with a larger diameter than the roll journal. A nip may be formed between the calendaring sections, the length of the nip may correspond to the length of the calendaring section. It may be provided that an electrode film is formed with as uniform a thickness distribution as possible by feeding the powdered electrode precursor material into the nip uniformly over the length of the nip.

[0012] In particular, it may be provided that the pretensioning device comprises a double eccentric, which comprises an inner eccentric bush and an outer eccentric bush that are pivotable independently of one another. The inner eccentric bush may be at least partially accommodated in the outer eccentric bush. An outer surface of the inner eccentric bush may face an inner surface of the outer eccentric bush. A gap may be provided between the inner eccentric bush and the outer eccentric bush. The inner eccentric bush may partially protrude from the outer eccentric bush. The outer eccentric bush may have a section that extends away from the inner eccentric bush. The outer diameter of the inner eccentric bush may be smaller than the inner diameter of the outer eccentric bush. Furthermore, the inner eccentric bush may have an internal bore for accommodating the roll journal. The internal bores of the inner eccentric bush and the outer eccentric bush may be arranged eccentrically with respect to the respective outer diameters. The eccentricity of the inner bush and the outer eccentric bush may be adjusted such that in a starting position, the roll journal accommodated in the inner eccentric bush is accommodated or arranged in the center of the double eccentric. The calender may be provided with a device for axially pivoting the inner eccentric bush. The calender may further be provided with a device for axially pivoting the outer eccentric bush. This allows the inner and outer eccentric bushes to be pivoted independently of each other. By pivoting the inner and outer eccentric bushes relative to each other, it may be provided that the magnitude of the order of deflection can be adjusted. Furthermore, by pivoting both eccentric bushes relative to the bearing journal, it may be provided that the direction of deflection can be adjusted. The double eccentric, in cooperation with the associated roll bearing, allows the roll to bend. The roll bearing may be axially spaced from the double eccentric on the roll and further arranged towards the center of the roll.

[0013] It is conceivable that the first nip roll or the second nip roll is rotatably mounted in the inner eccentric bushing. The respective roll journal can extend at least partially into the pretensioner or into the inner eccentric bushing.

[0014] It may further be provided that the outer eccentric bush is rotatably mounted relative to a bore arranged in the machine frame, in which the pretensioning device is accommodated. The bore may be introduced directly into the machine frame. Alternatively, the bore may be a cylinder liner inserted in the machine frame. A first radial bearing may be formed or arranged between the bore and the outer eccentric bush.

[0015] It may also be provided that the inner eccentric bush is rotatably mounted relative to the outer eccentric bush. A second radial bearing may be formed or arranged between the outer eccentric bush and the inner eccentric bush.

[0016] Furthermore, a third radial bearing can be formed or arranged between the inner eccentric bush and the roll journal. The first radial bearing and / or the second radial bearing and / or the third radial bearing can be designed as a cylindrical roll bearing or a needle bearing.

[0017] A first support roll may be arranged adjacent to the first nip roll and a second support roll may be arranged adjacent to the second nip roll, each support roll rotating in the opposite direction to the adjacent nip roll, in order to generate sufficient pressing force in the nip and to generate pretension. In particular, it may be provided that the diameter of the support roll is larger than the diameter of the first nip roll and the second nip roll. For example, the diameter of the roll may be about 150-250 mm, preferably 200 mm, and the diameter of the support roll may be 600-800 mm, preferably 700 mm. It may be provided that in the starting position of the double eccentric, the axes of the nip roll and the support roll are aligned with each other in one plane.

[0018] It may be provided that the first nip roll and the first support roll roll against each other and a nip for passing the electrode film is formed between the second nip roll and the second support roll, the second nip roll being designed to guide the electrode film around the upper or lower side of the second nip roll. In this case, the first support roll and the first nip roll may be in direct contact with each other so that the first nip roll can be supported on the first support roll. The second nip roll and the second support roll may be spaced apart from each other due to the provided nip. However, the second nip roll may also be indirectly supported on the second support roll via the electrode film guided through the nip.

[0019] A device for continuously conveying the powdered electrode precursor material into the nip can be arranged above the nip between the first nip roll and the second nip roll. The device includes a hopper for receiving the powdered electrode precursor material, which can extend across the entire width of the nip. Below the hopper, a conveying gap can be provided for targeted conveyance of the powder into the nip.

[0020] It may be provided that at least one of the first nip roll or the second nip roll is provided with a pretensioning device on its facing roll journal, but it may also be provided that both the first nip roll and the second nip roll are provided with a pretensioning device on their facing roll journals, respectively, which means that both nip rolls can be pretensioned independently of each other or also against each other.

[0021] The present invention further relates to a method for producing an electrode film having a uniform thickness from a powdered electrode precursor material, the method comprising the steps of: Conveying powdered electrode precursor material into a nip formed by two nip rolls. Passing a powdered electrode precursor material through the nip, where the powdered electrode precursor material is subjected to a shear force as it passes through the nip, thereby forming an electrode film. Applying a pretension to at least one of the two nip rolls to counteract a force vector generated by the powdered electrode precursor material passing through the nip of each of the nip rolls.

[0022] The application of pretension may be provided by including a radial deflection of at least one roll journal of each nip roll.

[0023] It may further be provided that the radial deflection of at least one roll journal comprises a relative and / or uniform pivoting of a double eccentric provided on the roll journal, the relative and / or uniform pivoting in particular affecting an inner and an outer eccentric bushing of the double eccentric.

[0024] The radial deflection includes deflection of two opposing roll journals of at least one of the nip rolls, and it can be provided that both roll journals are radially deflected in the same direction, which can mean, for example, that both roll journals are deflected downwards or horizontally towards one side of the roll axis when the roll axis is viewed from above.

[0025] Furthermore, it may be provided that the radial deflection includes deflection of two opposing roll journals of both nip rolls, the opposing roll journals being respectively deflected in the same direction, the roll journals of the first nip roll and the second nip roll being deflected in the same direction or in diametrically opposite directions, for example, adjacent roll journals may both be deflected downwards or upwards, towards or away from each other.

[0026] The method may further include supporting each of the two nip rolls by a line force acting radially on the side of the nip roll away from the nip, the line force being transmitted, for example, via a support roll disposed adjacent to the two nip rolls.

[0027] The present invention further relates to an electrode film having a uniform thickness, with a thickness variation of 10 μm or less across the width of the electrode film, obtained by passing a powdered electrode precursor material through a nip formed between first and second nip rolls, in the process applying a shear force to the powdered electrode precursor material to form the electrode film, and applying a pretension to at least one of the nip rolls to counteract a force vector resulting from the powdered electrode precursor material passing through the nip of each nip roll.

[0028] The electrode film can be one or more of an anode film, a cathode film, a separator film, a current collector film, an interlayer film, an adhesive film, a primer film, or a laminate composed of some of the above films.

[0029] Further details of the invention are explained using the following figures. [Brief description of the drawings]

[0030] [Figure 1] FIG. 1 shows a schematic diagram of a double eccentric for radially deflecting a bearing journal. [Diagram 2] FIG. 2 shows a schematic diagram of roll deflection that may be caused by radial deflection of the roll journal of the roll. [Diagram 3] FIG. 2 shows a side view of an installation of two calendars according to the invention arranged opposite each other. [Figure 4] FIG. 13 shows a perspective view of roller alignment with no or prevented deflection. [Figure 5A] 1 illustrates an illustration of the interaction of the dual eccentrics with the resulting horizontal inward deflection of the calender rolls at the nip. [Figure 5B] 1 illustrates an illustration of the interaction of the dual eccentrics with the resulting horizontal outward deflection of the calender rolls at the nip. [Figure 5C] 1 illustrates an illustration of the interaction of the dual eccentrics with the resulting opposing vertical deflections of the calender rolls at the nip. [Figure 5D] 1 illustrates an illustration of the interaction of the dual eccentrics with the resulting opposing vertical deflections of the calender rolls at the nip. [Figure 6A] FIG. 2 shows a perspective view of a calender roll in combination with an adjacent support roll. [Figure 6B] 1 shows a perspective view of a calender roll in combination with an adjacent support roll, and powdered electrode precursor material being conveyed into the nip, or the electrode film formed after the nip. [Figure 7A] FIG. 1 shows a perspective view of a calender roll in combination with an adjacent support roll, where both calender rolls have avoidance bending induced by the compression process, resulting in non-uniform thickness distribution of the electrode film. [Figure 7B] FIG. 1 shows a perspective view of a calender roll in combination with an adjacent support roll, where one of the calender rolls has a deflection bend induced by the compression process, resulting in a non-uniform thickness distribution of the electrode film. [Figure 8A] FIG. 1 shows a perspective view of a calender roll in combination with an adjacent support roll, where proper alignment of the calender rolls results in uniform thickness distribution of the electrode film. [Figure 8B] FIG. 1 shows a perspective view of a calender roll combined with an adjacent support roll, where the calender rolls are correctly aligned to provide a uniform thickness distribution of the electrode film and the electrode film is guided around one support roll. [Figure 9A]1A-1D show an exemplary side view of an electrode film manufacturing process in a calendar according to the present invention. [Figure 9B] 1A-1D show exemplary top views of an electrode film manufacturing process in a calendar in accordance with the present invention. [Figure 10] FIG. 2 shows a perspective view of a roll journal mounted in a pretensioning device according to the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0031] FIG. 1 shows an exemplary double eccentric 99 used to deflect the roll journal 205 at an adjustable amount at any angle perpendicular to the central axis of each nip roll 201, 202. The double eccentric 99 includes an outer eccentric bushing 101, whose inner bore is eccentric with respect to the outer diameter. The double eccentric 99 also includes an inner eccentric bushing 102, whose inner bore is concentric with the outer diameter of the outer eccentric bushing in the starting position. The double eccentric 99 is configured to deflect the nip rolls 201, 202 by deflection of the roll journal 205 with the pretensioner 100, such that the deflection of the nip rolls can be countered by the force vector F generated in the nip by the electrode powder. The inner eccentric bushing 102 and the outer eccentric bushing 103 can pivot relative to each other or in the same direction, so that the eccentricity of the inner eccentric bushing's inner bore is adjustable and the direction and degree of deflection are variable. Each eccentric bushing 102, 102 has a thicker section and a thinner section opposite the thicker section. In the starting position, the thicker section of the outer eccentric bushing 101 is adjacent to the thinner section of the inner eccentric bushing 102, and the thinner section of the outer eccentric bushing 101 is adjacent to the thicker section of the inner eccentric bushing 102. The maximum possible deflection off-centre can be achieved when both eccentric bushings 101, 102 are rotated by 180° relative to each other.

[0032] Fig. 2 illustrates possible deflections of a nip roll 201 with a pretensioning device 100 on each of two opposing roll journals 205, which can be realized by rotating the eccentric bushes 101, 102 relative to a starting position. Fig. 2 includes representations of a rotation of the eccentric bushes 101, 102 resulting in a vertical downward deflection of the roll journal 205, a rotation of the eccentric bushes 101, 102 resulting in a horizontal leftward deflection of the roll journal 205, a rotation of the eccentric bushes 101, 102 resulting in a vertical upward deflection of the roll journal 205, and a rotation of the eccentric bushes 101, 102 resulting in a horizontal rightward deflection of the roll journal 205. The corresponding pivot directions of the inner and outer eccentric bushes are shown in each case. For example, to deflect the roll journal 205 vertically upwards, the outer eccentric bushing 101 together with the inner eccentric bushing 102 is first pivoted counterclockwise by approximately 120° as shown in the figure, and then the inner eccentric bushing 102 is pivoted back clockwise by approximately 90° relative to the outer eccentric bushing 101. Further deflection positions are set in a corresponding manner, as indicated by the direction of the arrows illustrated in each case.

[0033] FIG. 3 shows a side view of a calender 10 showing the arrangement of rolls 201, 202 relative to support rolls 301, 302 in an integrated rolling system according to an embodiment. The calender 10 is used to produce a separator film 303 coated on both sides with an electrode film 613. The device 2 has two calender devices arranged side by side in front of each other, which have opposite main transport directions Y1, Y2. The calender devices each have six rolls 301, 201, 202, 302, 401, in each case the input end roll 301 is designed as a support roll 301 rolling directly on the first nip roll 201, and the output end roll forms a common end nip 13. The separator film 303 is fed vertically from above into the end nip 13 and coated on both sides by the electrode film 613 produced by the two calendaring apparatuses, so that the coated separator film 303 exits the end nip 13 vertically downwards where it can be cut to length and / or wound up or further processed.

[0034] 4 shows the alignment of the nip rolls 201, 202 without deflection and thus with one or more pretensioning devices 100 provided on the nip rolls 201, 202 in a starting position. This alignment comprises a nip roll 201 disposed adjacent and parallel to a second nip roll 202.

[0035] 5A-5D show the interaction of the inner eccentric bushing 102 and the outer eccentric bushing 202 of the nip rolls 201, 202 in aligning the nip roll deflection with the force vector F acting on the nip 210. FIG 5A shows the nip roll 201 in line with the second nip roll 202, with the eccentric bushings 102, 102 of the first nip roll 201 aligned to cause a horizontal left deflection of the roll journal 205 and therefore a horizontal right deflection of the roll, and the eccentric bushings 102, 102 of the second nip roll 202 aligned to cause a horizontal right deflection of the roll journal 205 and therefore a horizontal left deflection of the roll. FIG. 5B shows a nip roll 201 in line with a second nip roll 202, with the eccentric bushings 102, 102 of the first nip roll 201 aligned to cause a horizontal deflection of the roll journal 205 to the right and therefore a horizontal deflection of the roll to the left, and the eccentric bushings 102, 102 of the second nip roll 202 aligned to cause a horizontal deflection of the roll journal 205 to the left and therefore a horizontal deflection of the roll to the right. FIG. 5C shows a nip roll 201 aligned with a second nip roll 202, with the eccentric bushings 102, 102 of the first nip roll 201 aligned to cause a vertical upward deflection of the roll journal 205 and therefore a vertical downward deflection of the roll, and the eccentric bushings 102, 102 of the second nip roll 202 aligned to cause a vertical downward deflection of the roll journal 205 and therefore a vertical upward deflection of the roll. FIG. 5D shows a nip roll 201 aligned with a second nip roll 202, with the eccentric bushings 102, 102 of the first nip roll 201 aligned to cause a vertical downward deflection of the roll journal 205 and therefore a vertical upward deflection of the roll, and the eccentric bushings 102, 102 of the second nip roll 202 aligned to cause a vertical upward deflection of the roll journal 205 and therefore a vertical downward deflection of the roll.

[0036] 6A-6B show the alignment of the nip rolls 201, 202 with the support rolls 301, 302 and the use of the rolls to manufacture an electrode film 613. This includes an arrangement of adjacent rolls including, from left to right, a first support roll 301, a first nip roll 201, a second nip roll 202, and a second support roll 302, all aligned with one another. Powdered electrode precursor material 905 is fed from above into the nip 210 between the two nip rolls 201, 202, where it is formed into an electrode film 613 and exits the nip 210 on the underside of the nip rolls 201, 202.

[0037] 7A-7B show unacceptable thickness tolerances resulting from the deflection of the nip rolls 201, 202 when no pretension is applied by the pretensioning device 100 according to the present invention. Due to the pressing force in the nip 210 caused by the electrode powder 905 being conveyed through the nip 210, the nip rolls 201, 202 are deflected upwards or avoid the pressing force. As a result, an electrode film 613 having an unacceptable thickness tolerance may be produced, specifically the thickness of the film may increase towards the center. As shown in FIG. 7B, the avoidance action of the nip rolls 201, 202 may be asymmetric, so that only one of the nip rolls 201, 202 is deflected or the nip rolls 201, 202 are deflected to different degrees. In the illustrated example, only the second nip roll 202 is deflected upwards and the first nip roll 201 is not deflected at all. This is because the first nip roll 201 and the first support roll 301 are in direct contact with each other, resulting in high friction therebetween, but the friction between the second nip roll 202 and the electrode film 613 is low.

[0038] Figures 8A-8B show an electrode film 613 with uniform layer thickness produced by correctly aligned nip rolls 201, 202 according to an embodiment. A correctly adjusted pretensioning device 100 ensures that the two nip rolls 201, 202 are correctly aligned so that there is no net deflection or the working forces present in the nip and the pretension forces cancel each other out, producing a film 613 with a uniform thickness distribution. Figure 8B shows the further feeding of the electrode film 613, which is guided around the rolls in a meandering manner in the main transport direction.

[0039] During operation, the nip rolls 201, 202 are deflected to condition the film 613 formed as the dry powder mixture 905 passes through the nip 210. In some embodiments, the deflection of the roll journal 205 is about 5 μm, about 10 μm, about 15 μm, about 20 μm, about 25 μm, about 30 μm, about 35 μm, about 40 μm, about 45 μm, about 50 μm, about 55 μm, about 60 μm, about 65 μm, about 70 μm, about 75 μm, about 80 μm, about 85 μm, about 90 μm, about 95 μm, or about 100 μm, in each case based on a roll having a diameter of about 200 mm. Alternatively, the magnitude of the deflection can be expressed as a ratio selected based on the overall dimensions of the pressure roll. In one embodiment, the deflection ratio is about 2.5×10 based on the amount of deflection of the roll divided by the roll diameter. -5 ~ approx. 0.0005, approx. 5×10 -5 ~ 0.0005, or 7.5 x 10 -5 ~ about 0.0005. The above values ​​are given based on a nip roll with a diameter of 200 mm, but the roller diameter is not so limited.

[0040] In addition to the amount and direction of roll deflection, the nip rolls 201, 202 can be individually controlled by rotating only the eccentric bushings connected to each individual roll. This allows the user to further control the distance between the rolls and, as a result, the thickness of the film passing between the rolls. The direction of rotation is not limited, and each of the eccentric bushings 101, 102 can be rotated separately by any amount. Additionally, the individual eccentric bearings connected to a particular nip roll can be adjusted, allowing further control over the deflection of each roll.

[0041] In some embodiments, the nip rolls 201, 202 have a crown, which is used to further increase the accuracy and precision with which the rolls exert on the electrode film 613. The crown ensures that the contact surface, and thus the film profile and thickness, remains flat and precise even when the roll is deflected or otherwise manipulated. The height of the crown is not limited and is selected according to the requirements of the particular film and the deflection selected for each roll. In some embodiments, the crown of the pressure roller is about 3 μm, about 4 μm, about 5 μm, about 6 μm, about 7 μm, about 8 μm, about 9 μm, about 10 μm, or any range of the above values, such as about 3 μm to about 10 μm, about 4 μm to about 9 μm, or about 4 μm to about 8 μm.

[0042] The film 613 formed by the nip rolls 201, 202 may be, but is not limited to, metal, polymer, paper, ceramic, or a mixture or laminate of one or more of these. In certain embodiments, the film is formed from a dry powder that is then formed as part of a lithium ion cell. Once the film is formed from the dry powder, it is shaped into the shape of a cathode or anode for constructing a battery.

[0043] In addition to adjusting the nip 210 between the nip rolls 201, 202 to control the thickness of the film, the pressure applied to the film can also be adjusted using the nip rolls 201, 202 and the pretensioner 100. The magnitude of the force applied by the first nip roll 201 or the second nip roll 202, which is solely due to the adjustment made by the eccentric bearing and in the absence of any external structure or device, can be up to about 75 kN, up to about 50 kN, up to about 25 kN, about 1 kN to about 75 kN, about 1 kN to about 50 kN, about 10 kN to about 50 kN, about 10 kN to about 40 kN, about 10 kN to about 30 kN, or any combination of one or more of the above ranges. In this way, the first nip roll 201 and the second nip roll 202 can each be independently adjusted to apply a large pressure to the powder or film. It is contemplated that the above pressures are solely due to the adjustments made by the dual eccentric 99, and that the first nip 210 and the second nip 210 may each exert additional forces based on other structures within the apparatus.

[0044] Alternatively, the precision of the dual eccentric 99 and associated nip rolls 201, 202 is measured by the uniformity of the film 613 formed by the nip rolls 201, 202. In some embodiments, the measured thickness variation of the cathode or anode film formed by the nip rolls 201, 202 is about 10 μm or less, about 8 μm or less, about 6 μm or less, about 4 μm or less, about 3 μm or less, about 2 μm or less, about 1 μm or less, about 1-10 μm, about 1-8 μm, about 1-6 μm, about 1-4 μm, about 1-3 μm, or about 1-2 μm. The above values ​​are measured across the width of the film required for the form factor of the battery being manufactured.

[0045] In the above paragraphs describing the precision of the eccentric bearings and associated nip rolls as measured by nip roll crown, force applied to the nip rolls, and film uniformity, these values ​​are in turn measured with respect to the width required for the cell form factor, such as lithium ion cells, that will be manufactured using this apparatus. Examples of form factors include, but are not limited to, cylindrical cells 10440 or 1044 (10 mm diameter, 44 mm length), 14500 or 1450 (14 mm diameter, 50 mm length), 16340 or 1634 or CR123A (16 mm diameter, 34 mm length), 18650 or 1865 (18 mm diameter x 65 mm length), 21700 or 2170 (21 mm diameter x 70 mm length), 26650 or 2665 (26 mm diameter x 65 mm length), 32650 or 3265 (32 mm diameter x 65 mm length), and 4680 (46 mm diameter x 80 mm length). Prismatic and pouch type cells are also contemplated, with no limitations on the dimensions considered.

[0046] The disclosed apparatus may further include one or more position sensors connected to the eccentric bearing 99, the nip rolls 201, 202, or both. The position sensors determine the amount of rotation of the eccentric bearing or the amount of rotation of the nip roll and provide a digital or analog signal corresponding to that amount of rotation of the nip roll or eccentric bearing. Such position sensors include, but are not limited to, potentiometric sensors, capacitive position sensors, or optical position sensors. Optical position sensors can operate with any light, including ultraviolet (UV), visible light, or infrared. In certain embodiments, the light selected for the optical position sensor is a laser having one of the bandwidths described above.

[0047] In yet other embodiments, or in combination with the provided position sensor, one or more layer thickness sensors may be provided. The film thickness sensor includes, but is not limited to, an optical sensor, such as a laser sensor. The film thickness sensor determines the thickness of the film formed by the pressure roll by measuring the film thickness at at least one point on the film. In some embodiments, there are one or more film thickness sensors configured to measure the thickness at multiple points across the width of the film. The thickness sensor provides a digital or analog signal corresponding to the thickness of the film.

[0048] The use of the nip rolls 201, 202 and associated components of the present disclosure is not limited, but certain uses are desirable. In some embodiments, a production line is constructed that includes the nip rolls of the present disclosure as well as various other components known to those skilled in the art. The nip rolls are used throughout the production line to precisely control the thickness of the film produced. Examples of films configured to be formed with or to use the nip rolls and associated components of the present disclosure include one or more anode films, cathode films, separator films, current collector films, interlayer films, adhesive films, primer films, or laminates including two or more of the above films.

[0049] Although the disclosed nip rolls 201, 202 and related components have been disclosed as being useful for forming films from powders, there are other applications, for example, it is contemplated that the nip rolls and related components can form films of liquids or non-Newtonian fluids, such as slurries.

[0050] 9A and 9B show an illustration of a particularly advantageous embodiment of the present disclosure. According to Fig. 9A and 9B, the calender 10 comprises a first nip roll 201 and a second nip roll 202 arranged in close proximity to a powder hopper 904 for receiving a powder electrode material 905. Furthermore, a first support roll 301 and a second support roll 302 are arranged on one side of the first nip roll 201 and the second nip roll 202. In use, the electrode material 905, which is typically a powder for a dry electrode, is compressed by the first nip roll 201 and the second nip roll 202, thereby forming a dry electrode film 613. The dry electrode film 613 passes through the first nip roll 201 and the second nip roll 202, is deformed under pressure therefrom, and then is wound around the first calender roll 302 and the second calender roll 401. The dry electrode film 613 is compressed during its movement and exerts equal and opposite forces on the first pressure roller 201 and the second pressure roller 202. However, the first nip roll 201 and the second nip roll 202 experience different forces due to friction differences. In the illustrated example, the first nip roll 201 is biased and must be pretensioned accordingly by the pretensioning device 100 (not shown). The second nip roll 202 is surrounded by the dry electrode 613 and is not biased as shown. Therefore, the second nip roll 202 does not need to be adjusted to the extent required for the first nip roll 201.

[0051] 9B, the first nip roll 201 and the second nip roll 202 are adjusted by one or more pretensioning devices 100 such that the magnitude of the adjusted force on the first nip roll 201 is greater than the magnitude of the adjusted force on the second nip roll 202. As a result, a uniform and precisely controlled gap between the first nip roll 201 and the second nip roll 202 is ensured as the dry electrode film 613 passes therethrough.

[0052] FIG. 10 shows a cross-section through the nip roll 201 and the pretensioning device 100 mounted on the roll journal 205 of the nip roll 201. The roller 201 is mounted on the machine frame 500 by means of a roll bearing 700. The machine frame further comprises, in front of the rollers 201, 202, a bore 520 in which a cylinder bush is accommodated, in which the roll journal 205 of the nip rolls 201, 202 is accommodated and which is mounted on the pretensioning device 100. The pretensioning device 100 comprises a double eccentric 99, which essentially consists of an inner eccentric bush 102 and an outer eccentric bush 101. The inner eccentric bush 102 is inserted so as to overlap the outer eccentric bush 101. The outer eccentric bush 101 is mounted axially rotatably relative to the cylinder bush via a first radial bearing 110. The inner eccentric bush 102 is mounted relative to the outer eccentric bush 101 via a second axially rotatable radial bearing 120. The roll journal 205 is mounted axially rotatably relative to the inner eccentric bush 102 via a third radial bearing 130. In the illustrated orientation, the double eccentric 99 is in its starting position, in which the thick part of the outer eccentric bush is adjacent to the thin part of the inner eccentric bush 102 and the thin part of the outer eccentric bush 101 is adjacent to the thick part of the inner eccentric bush 102, so that the roll journal is centered and not deflected. The eccentric bushes 101 and 102 are adjustable independently of each other by separate pivot devices. To create a defined roll bend at the roll center, the double eccentric 99 in which the roll journal 205 is housed is deflected relative to the roll bearing 700 in such a way that the distance between the double eccentric 99 and the roll bearing 700 acts as a lever arm.

[0053] The features of the invention disclosed in the above description, in the drawings and in the claims may be essential for the implementation of the invention both individually and in any combination. [Explanation of symbols]

[0054] (List of reference numbers) 10. Calendar 100 Pretensioning device 99 Double Eccentric 101 Outer eccentric bush 102 Inner eccentric bush 110 First radial bearing 120 Second radial bearing 130 3rd radial bearing 201 First nip roll 202 Second nip roll 205 Roll Journal 206 Calendaring Section 210 Nip 301 First supporting roll 302 Second Support Roll 303 Separator Film 401 Calendar Roll 500 Machine Frame 520 Bore 613 Electrode Film 700 Roll Bearing 904 Powder Hopper 905 Powder electrode precursor material D1 Roll diameter D2 Support roll diameter F force vector X deflection direction

Claims

1. 1. A calender for producing an electrode film from a powder-type electrode precursor material, comprising: at least one first nip roller and at least one second nip roller rotating in a direction opposite to that of the first nip roller forming a nip therebetween, the calendar being designed to apply a shear force to the powdered electrode precursor material as it passes through the nip, thereby forming an electrode film; At least one of the first nip roller or the second nip roller has at least one pretensioning device for pretensioning the nip roller against a non-axial, in particular radial and / or tangential, force vector (F) generated in the nip by a compression process and acting on the respective nip roller, the pretensioning device being capable of adjusting the direction of the pretension and / or the magnitude of the pretension. The calendar,

2. 2. The calendar according to claim 1, wherein both nip rollers are mounted in a machine frame via their respective front roller journals, and the pretensioning device is assigned to at least one bearing of the first nip roller or the second nip roller, and the pretensioning device allows the roller journal to be radially deflected in any direction and with an adjustable magnitude relative to the at least one bearing.

3. 2. The calendar of claim 1, wherein the pretensioning device comprises a double eccentric, the double eccentric having an inner eccentric bushing and an outer eccentric bushing that are rotatable independently of each other.

4. 4. The calendar of claim 3, wherein the first nip roller or the second nip roller is rotatably mounted within the inner eccentric bushing.

5. 4. A calendar as claimed in claim 3, wherein said outer eccentric bushing is rotatably mounted relative to a bore disposed in said machine frame, said bore receiving said pretensioning device.

6. 6. The calendar of claim 5, wherein a first radial bearing is formed or disposed between said bore and said outer eccentric bushing.

7. 4. The calendar of claim 3, wherein a second radial bearing is formed or disposed between the outer eccentric bushing and the inner eccentric bushing.

8. 4. The calendar of claim 3, wherein a third radial bearing is formed or disposed between said inner eccentric bushing and said roller journal.

9. 7. The calendar according to claim 6, wherein the first radial bearing and / or the second radial bearing and / or the third radial bearing are designed as cylindrical roller bearings or needle bearings.

10. 2. The calendar of claim 1, wherein a first support roller is disposed adjacent to the first nip roller and a second support roller is disposed adjacent to the second nip roller, each of the support rollers rotating in an opposite direction to the adjacent nip roller.

11. 11. The calendar of claim 10, wherein the diameter (D2) of the support roller is greater than the diameters of the first nip roller and the second nip roller.

12. 11. The calendar of claim 10, wherein the axes of the nip rollers and the support rollers are coplanarly aligned with one another.

13. 11. The calendar of claim 10, wherein the first nip roller and the first support roller roll against each other, a nip is formed between the second nip roller and the second support roller for passing the electrode film, and the second nip roller is designed to guide the electrode film around an upper or lower side of the second nip roller.

14. 2. The calendar of claim 1, wherein a device for continuously conveying powdered electrode precursor material into the roller nip is disposed above the roller nip between the first nip roller and the second nip roller.

15. 2. The calendar of claim 1, wherein at least one of the first nip roller or the second nip roller includes a pretensioner on each of its opposing roller journals.

16. 2. The calendar of claim 1, wherein both the first nip roller and the second nip roller are provided with a pretensioning device on each of their respective opposing roller journals.

17. A method for producing an electrode film having a uniform thickness from a powder-type electrode precursor material, comprising the steps of: conveying a powdered electrode precursor material into a nip formed by two nip rollers; passing the powdered electrode precursor material through the nip, the powdered electrode precursor material being subjected to a shear force as it passes through the nip to form an electrode film; applying a pretension to at least one of the two nip rollers to counter a force vector (F) generated by the passage of the powder-type electrode precursor material through the nip of the respective nip roll; The method comprising:

18. The method of claim 17 , wherein the applying of the pretension comprises radial deflection of at least one roller journal of the respective nip roller.

19. 20. The method of claim 18, wherein the radial deflection of the at least one roller journal comprises relative and / or uniform pivoting of a double eccentric provided on the roller journal.

20. 20. The method of claim 18, wherein the radial deflection comprises deflection of two opposing roller journals of at least one of the nip rollers, both roller journals being radially deflected in the same direction.

21. 20. The method of claim 18, wherein the radial deflection comprises the deflection of two opposing roller journals of both nip rollers, the opposing roller journals being respectively deflected in the same direction, and the roller journals of the first nip roller and the second nip roller being deflected in the same direction or in diametrically opposite directions.

22. 20. The method of claim 17, further comprising supporting both nip rollers on each side of the nip roller away from the nip by a line force acting radially relative to each of the nip rollers.

23. 1. An electrode film having a uniform thickness, with a thickness variation of 10 μm or less in a width direction of the electrode film, obtained by passing a powder-type electrode precursor material through a nip formed between a first nip roller and a second nip roller, during which the powder-type electrode precursor material is subjected to a shear force to form an electrode film, and applying a pretension to at least one of the nip rollers to counter a force vector (F) generated by the powder-type electrode precursor material passing through the nip of each of the nip rollers.

24. 24. The electrode film of claim 23, which is one or more of an anode film, a cathode film, a separator film, a current collector film, an interlayer film, an adhesive film, a primer film, or a laminate comprised of some of the above films.

Images