Method, device and mixture for cleaning surfaces, in particular calender rollers in the production of electrode material for accumulators

Abstract

The invention relates to a method for cleaning surfaces for producing electrode material in accumulators, in particular for cleaning calender rollers (2, 3) in anode and / or cathode foil production. In particular, according to the invention, a carrier material (13) is moistened with a mixture, pressed against a roller (2, 3), and contamination is removed, preferably from the surface of the roller (2, 3), by the relative movement of the carrier material (13) and the surface of the roller (2, 3).

Description

[0001] METHOD, DEVICE AND MIXTURE FOR CLEANING SURFACES, IN PARTICULAR CALENDAR ROLLERS IN THE PRODUCTION OF ELECTRODE MATERIAL FOR BATTERIES

[0002] Description

[0003] Modern rechargeable batteries, or electric batteries, generally consist of many individual cells connected together to form modules for storing and distributing electricity. These cells predominantly have one electrode made of lithium metal oxide, sodium metal oxide, or another alkali metal metal oxide (called the cathode) and a second electrode (the anode), usually made of graphite. During discharge, the cathode is the positive electrode. During charging, the cathode is the negative electrode. Mobile lithium / sodium ions are stored in the cathode and migrate to the anode during charging. Ions are electrically charged particles.

[0004] The individual cells generally consist of alternating layers of anode material, cathode material, and separator foils. The electrode material of the anode and cathode consists of a carrier foil coated with the appropriate active material. Cathodes are predominantly made of aluminum foil with a lithium / sodium metal oxide coating. Anodes, on the other hand, consist of copper foil with a graphite coating. The coating is a viscous mixture, known as battery paste or slurry, and is typically applied directly to the carrier foil in a roll-to-roll process using slot nozzles.

[0005] Before the electrodes can be assembled into individual cells, the coated foils must be calendered with a defined and uniform line pressure. For anode production, the calender rollers are typically heated to a controlled temperature range of 20 to 60°C, while cathode production uses process temperatures of 80 to 150°C. During this process step, the calender rollers come into direct contact with the applied coating materials and become continuously contaminated. Parts of the coating material are deposited on the mostly metallic, mirror-polished roller surfaces, forming an increasing layer.

[0006] This described coating reduces the uniformity of the calendering process and thus the quality of the calendered material. Additionally, during calendering, larger particles of the coating can clump together to form conglomerates and adhere to the surface as lumps or spots. These spots can lead to recurring defects on the calendered material (imprint points).

[0007] In current technology, the surfaces of calender rolls are cleaned manually at regular intervals using textiles and solvents. For the production of anode material, only simple solvents or distilled water are used in the typical temperature range below 60°C. Due to the elevated surface temperature of up to 150°C, volatile or flammable solvents cannot be used to clean the roll surfaces after or during cathode production. In the current cleaning process, the rolls must be cooled down, which is time-consuming and energy-intensive, before they can be cleaned of deposits with chemical cleaners.

[0008] Productivity and the avoidance of downtime and scrap are two of the most important operational metrics in the calendering of electrode material. Even more essential is the absolute and consistent quality of the produced material, as even the slightest deviations can lead to total failure of the entire battery cell, ultimately resulting in the failure of the electric vehicle.

[0009] The present invention attempts to solve or at least mitigate some of the problems associated with the prior art. In light of the above, it is an object of the present invention to increase productivity, reduce downtime, and ensure product quality during anode and cathode calendering.

[0010] The aforementioned object of the present invention is achieved by a method for cleaning surfaces for the production of electrode material in accumulators according to independent claim 1 and by a device for cleaning surfaces for the production of electrode material in accumulators according to independent claim 19. Furthermore, the aforementioned object of the present invention is achieved by a mixture for cleaning surfaces for the production of electrode material in accumulators according to independent claims 11 and 14. Further embodiments are disclosed in the accompanying dependent claims.

[0011] According to a first aspect of the invention, a method for cleaning surfaces for the manufacture, preferably during the manufacture, of electrode material in accumulators, in particular for cleaning calender rolls in the production of anode and / or cathode foils, is provided. Essentially, a carrier material is moistened with a mixture, pressed against a roll, and the contaminants are removed, preferably from the surface of the roll, by relative movement of the carrier material and the surface of the roll.

[0012] This offers the advantage that the surfaces of the calender rolls can be cleaned during the electrode material manufacturing process. Furthermore, it eliminates the need to cool the calender rolls before cleaning. This also significantly reduces downtime, even when cleaning is performed during production shutdowns. The roll can be configured as a calender roll for anode and / or cathode foil production.

[0013] Pressing against a roller by a relative movement of the carrier material and the surface of the roller means that the carrier material can be moved towards the surface of the roller and / or the surface of the roller can be moved towards the carrier material. This means that either the carrier material or the roller, or both, can be moved to exert pressure.

[0014] It can be provided that the support material and / or the mixture is selected according to the temperature range of the anode (up to 60°C) or the cathode (up to 150°C). This means that the support material and / or the mixture are neither volatile nor flammable at the maximum possible temperatures. As a result, the calender rolls no longer need to be cooled to perform the cleaning of the calender roll surfaces. Because cooling is no longer necessary, downtime is significantly reduced, even when cleaning is performed during shutdown. It is advantageous that the invention automates the cleaning process and reduces it to less than 8 minutes. The support material can be a suitable carrier material. The mixture can be a suitable mixture.Suitable can preferably mean that the carrier material and / or the mixture is usable in the temperature range of the anode (up to 60°C) or the cathode (up to 150°C) in the production of electrode material.

[0015] The relative motion of the substrate material and the surface of the roller can be generated, for example, by rotating the roller while the substrate material remains stationary. Alternatively, the relative motion can also be generated by rotating both the roller and the substrate material, in which case the rotations of the roller and the substrate material differ in speed and / or direction.

[0016] It can be provided that the cleaning takes place during ongoing production, preferably during the manufacture of electrode material for accumulators, in particular the cleaning of calender rollers in the anode and / or cathode foil production, thereby eliminating or minimizing all downtime for cleaning.

[0017] It may be provided that a cloth, fabric, textile, nonwoven, sponge of both artificial and natural origin, elastomer or thermoplastic structural material is used as the carrier material, preferably a knitted lint-free cloth, preferably a microfiber cloth.

[0018] According to another embodiment of the method, the carrier material is stretched over a plastic surface or rubber strip, which is pressed against the rotating surface of the roller, so that the carrier material rests between the plastic surface or rubber strip and the roller surface. In such a embodiment, the mixture is applied to the carrier material (e.g., a cloth), which is then stretched over the plastic surface or rubber strip and brought into contact with the rotating roller surface. The relative movement between the two parts is created by the contact of the carrier material with the rotating roller.

[0019] According to another embodiment of the method, the carrier material is moistened from the direction of the plastic surface or the rubber strip via a moistening device, preferably a spray or application system. This allows the cloth to be moistened in a controlled manner from the direction of the plastic surface or the rubber strip by active spraying.

[0020] According to another embodiment of the method, the carrier material is actively moved towards or away from the surface of the roller, preferably via a traversing unit, thereby initiating or de-entering contact between the carrier material and the surface to be cleaned. Alternatively or additionally, the roller can be actively moved towards or away from the carrier material, thereby initiating or de-entering contact between the carrier material and the surface to be cleaned. This means that either the carrier material is moved towards the surface of the roller, the roller is moved towards the carrier material, or both the carrier material and the roller are moved towards or away from each other.

[0021] According to another embodiment of the method, the carrier material is unwound from a clean cloth spindle (also called an unwind spindle) onto a soil cloth spindle (also called a rewind spindle), so that the need for fresh carrier material can be controlled and metered. Preferably, the unwinding can be motorized or manual. This allows the consumption of the carrier material to be monitored and new carrier material to be used as needed, e.g., in case of heavy soiling.

[0022] According to another embodiment of the method, a brush is used as the carrier material. Additionally, the brush can be designed to rotate and / or perform lateral movements for cleaning purposes. Lateral movements are understood to mean that the bristles of the brush move longitudinally along the roller surface.

[0023] According to another embodiment of the method, the contamination is transferred from the surface to the carrier material by means of a constant contact pressure over a defined period of time.

[0024] According to another embodiment of the method, alternating cycles with moistened and dry carrier material completely clean the entire surface, leaving it clean and dry. In another embodiment, the surface is cleaned and moistened by the first moistened carrier material, and then cleaned and dried by a second, subsequent carrier material. "Subsequent" here means subsequent in the direction of rotation of the roller. This results in particularly thorough cleaning. The first moistened carrier material and the second, dry carrier material can be formed from spatially separated areas of a single carrier material.

[0025] According to another embodiment of the method, the cloth is moistened by an integrated tank or intermediate tank through capillary action of the cloth fibers.

[0026] According to another embodiment of the method, the carrier material is moistened from within a pressure element or the brush. The pressure element may be used to press the carrier material against a roller surface.

[0027] According to another embodiment of the method, the carrier material was already impregnated with the mixture before it was used.

[0028] According to another embodiment of the method, the moistening is carried out by an external dosing system, preferably an external spray tube, preferably not from the direction of the pressure element.

[0029] According to another embodiment of the method, color particles are added to the mixture before moistening the carrier material in order to detect the spray distribution of the mixture on and / or in the carrier material.

[0030] According to a further aspect of the invention, a mixture for cleaning surfaces is provided, preferably for the production of electrode material in accumulators, and in particular for cleaning calender rolls in cathode film production. It is essential that the mixture contains, or preferably consists of, at least one ester, and / or polyvalent alcohol, and / or glycol, and / or glycol ether, and / or long-chain alcohol, or a possible combination of several or all of the aforementioned substances. The mixing ratio depends on the flash point of the individual components, and / or the desired flash point of the mixture, and / or the characterization of the individual components. For a mixture of ester, alcohol, and glycol, a mixing ratio of ester: 60–80%, alcohol: 10–30%, and glycol: <10% is preferred. According to another embodiment, this mixture can be used as a mixture in the cleaning process.

[0031] A particularly effective mixture was found after extensive process testing, comprising or consisting partly of triethyl citrate, propylene glycol, and butyldiglycol, which can be used for purification in cathode manufacturing. According to another embodiment, this mixture can be used as a component in the purification process.

[0032] In a particularly advantageous and economical design, components from the following three groups are mixed or used in the cathode cleaning process. a) 1,2-Propanediol (1,2-propylene glycol), also known as propylene glycol, is a clear, colorless, almost odorless, and highly hygroscopic liquid. 1,2-Propanediol belongs to the polyhydric alkanols. b) Triethyl citrate (triethyl citrate) is the ester formed from the esterification of ethanol with citric acid. c) Butyldiglycol (systematically: 2-(2-butoxyethoxyethanol)) is a low-volatility (i.e., high-boiling) clear liquid with a very faint odor. BDG belongs to the group of glycol ethers.

[0033] In a preferred embodiment that does not require labeling, components from group c) are mixed to a maximum of 10% of the total solution. The remaining 90% of the total solution is mixed from groups a) and b) in any desired ratio. According to another embodiment, this mixture can be used as a mixture in the purification process.

[0034] According to a further aspect of the invention, the mixture additionally contains color particles. This allows the spray distribution in the carrier material to be checked. According to another aspect of the invention, a mixture is provided for cleaning surfaces, preferably in the production of electrode material for accumulators, and in particular for cleaning calender rolls in anode foil production. It is essential that the mixture comprises, or preferably consists of, at least deionized or distilled water and an alcohol, and / or glycol, and / or glycol ethers, in order to modify the evaporation properties. The mixing ratio depends on the flash point of the individual components, and / or the desired flash point of the mixture, and / or the identification of the individual components. According to another embodiment, this mixture can be used as a mixture in the cleaning process.

[0035] The mixture for cleaning deposits from anode production can therefore contain, or preferably consist of, at least deionized or distilled water and an alcohol and / or glycol and / or glycol ethers, in order to modify its evaporation properties. With a mixture of distilled water and alcohols and / or glycols and / or glycol ethers, it has been found that these additives lower the evaporation point, thus resulting in faster drying on the surface, which can reach temperatures of up to 60°C. This improved drying enabled continuous cleaning during ongoing production without affecting the quality of the produced material.The use of such a mixture in the cleaning process during anode production therefore enables particularly efficient operation of the calender systems and prevents downtime due to technically unclean surfaces resulting from production-related deposits of battery paste.

[0036] According to another embodiment of the mixture for cleaning in anode foil production, the already water-containing mixture can be further diluted with deionized water in a mixing ratio of 100:1 to 1:100. According to another embodiment, this mixture can be used as a mixture in the cleaning process.

[0037] Distilled water is suitable for anode production. Deionized water is water that has been purified to the point where (most) of its mineral and salt ions have been removed. Salt ions are also removed from distilled water through evaporation. The main difference between deionized and distilled water is that distilled water generally contains fewer organic impurities; deionization does not remove uncharged molecules, viruses, or bacteria, but deionized water usually has fewer mineral ions.

[0038] The mixtures used for cathode foil production and anode foil production offer the advantage of being able to chemically dissolve the coating materials while simultaneously withstanding the respective high surface temperatures. These mixtures improve the use of (cloth) cleaning systems, particularly in cathode and anode manufacturing. A significant advantage of these mixtures is that no chemical residues remain on the calender rolls, which could contaminate or damage the electrode material.

[0039] It may be provided that a specific selection of the aforementioned substances is used for the mixture, exhibiting sufficient resistance to the materials used in the system and simultaneously meeting the requirements of the production conditions with regard to evaporation and temperature stability. Preferably, the materials used are not altered by the mixture or the selection of the aforementioned substances. According to another embodiment, this mixture can be used as a component in the purification process.

[0040] A technical challenge in cathode foil production and anode foil production is the high surface temperature of up to 150°C during cleaning after calendering the cathode material. At these temperatures, all conventional cleaning agents evaporate before any chemical dissolution of the deposits can occur. Furthermore, components of the conventional mixtures remain as residues on the surface. According to another embodiment, the evaporation point of all components of the mixture is adjusted to the temperature range of the roller, preferably ±10°C. This effectively and demonstrably prevents dry residues. According to another embodiment, this mixture can be used as a component in the cleaning process.

[0041] It can be provided that the evaporation properties of the mixtures, preferably in the cleaning process, are adapted during both cathode and anode production so that the production conditions allow for continuous cleaning with moistened carrier material without bringing the film web to be produced into contact with residues of the respective mixture. This can be achieved by adjusting the mixture to the operating temperature of the respective calender roll so that, after cleaning, the mixture evaporates before the cleaned area of ​​the calender roll comes into contact with the film web. The mixing ratio depends on the flash point of the individual components, and / or the desired flash point of the mixture, and / or the identification of the individual components. According to another embodiment, this mixture can be used as a mixture in the cleaning process.

[0042] Without the cleaning device, preferably automatic, in conjunction with the respective mixtures, cleaning calender rolls during ongoing production is not possible according to the current state of the art. Before this invention, cleaning after anode production required interrupting the process for a considerable period of up to 50 minutes for manual hand washing. Cleaning after cathode production required interrupting the process for up to 8 hours to reduce the surface temperature from up to 150°C to at least below 50°C.

[0043] The following section will explain the chemical background of the cleaning process in more detail. To understand the cleaning effect, it is first necessary to analyze the form and type of contamination, which in the present electrode manufacturing process results primarily and almost exclusively from the ingredients of the battery pastes (the slurries). Typically, the slurries used for cathode production consist of active material, conductive additives, a binder, and a solvent. N-methyl(-2-)pyrrolidone (NMP) is typically used as the solvent to dissolve the binder polyvinyl fluoride (PVDF). Carbon black in the form of nanoparticles is used as the active material. These components of the slurry are partially built upon the mirror-polished, hard-chrome-plated steel cylinders.

[0044] To clean these deposits, a solvent must be used that dissolves the structure of the binder (PVDF) and simultaneously allows the remaining dirt particles (active material and additives) to be removed into the carrier material. According to the invention, this is achieved through the polarity of the mixture, preferably without a chemical reaction. This means that the dissolved deposits are not chemically altered by the mixture.

[0045] PVDF molecules can exist in different crystalline phases, some of which exhibit different polarities. The alpha phase has a nonpolar structure and therefore high chemical stability. The beta phase, on the other hand, is highly polar and exhibits the highest macroscopic polarity. The solvents used are correspondingly nonpolar, containing few polar groups.

[0046] The mixture must guarantee sufficient material compatibility with the materials used in the calender roll system and the cleaning device. Materials used in the device are preferably stainless steel (1.4301, 1.4305), anodized aluminum (AW-6063-T66), red brass RG7, copper and copper alloys (CuZn39Pb, brass, chrome-plated brass, nickel-plated brass), sealing materials (FKM, Viton, Viton Extreme), and sealing materials (PA6, PA12, Viton). This material compatibility is met by the aforementioned mixtures.

[0047] According to a further aspect of the present invention, the above-mentioned problem of increasing productivity, reducing downtime and ensuring product quality in the calendering of anode and cathode is solved by a device for cleaning surfaces for the, preferably in the, production of electrode material in accumulators, in particular for cleaning calender rolls in the anode and / or cathode foil production.Essentially, the device comprises a pressure element, a moistening device, and a carrier material, wherein the pressure element is designed to press the carrier material against a roller surface, and wherein the moistening device is designed to moisten the carrier material, and a) that the carrier material is designed as a cloth, fabric, textile, nonwoven, sponge of both artificial and natural origin, elastomer, or thermoplastic structural structure, and the device further comprises an unwind spindle and a winding spindle, wherein the carrier material is drawn from the unwind spindle to the winding spindle and is thereby tensioned over the pressure element, or b) that the carrier material is designed as a brush. The advantage of this is that the roller surface can be cleaned during operation.A further advantage of the device is that the surfaces of, for example, calender rolls can be cleaned during the electrode material manufacturing process. It is also advantageous that the calender rolls no longer need to be cooled to perform the cleaning. Because cooling is no longer necessary, downtime is significantly reduced, even when cleaning is performed while the machine is stopped. The roll can be configured as a calender roll for anode and / or cathode foil production.

[0048] Preferably, the entire width of the carrier material is pressed evenly onto the roller surface using the device according to the invention, thereby enabling complete cleaning of the roller surface. In a preferred embodiment, the width of the carrier material should be at least as wide as the maximum width of the film web. Preferably, this width is extended laterally by 10 mm to ensure that the full width of the soiling is covered even if the width of the cloth changes due to tension.

[0049] According to another embodiment, the pressure element is movable and can be moved towards or away from the roller surface. Preferably, the device includes a traversing unit designed to move the pressure element towards and away from the roller surface. This allows the carrier material to be actively moved against or away from the roller surface via the traversing unit, thereby initiating or de-entering contact between the carrier material and the surface to be cleaned. Preferably, the traversing unit is driven by a motor or manually.

[0050] According to another embodiment, preferably according to configuration a), the pressure element has a curved surface for guiding the carrier material. Alternatively or additionally, the pressure element, or at least a guide surface of the pressure element, is elastically designed. This allows any crowning of the roller surface to be compensated for by the shape and / or elasticity of the pressure element. According to another embodiment, preferably according to configuration a), the pressure element is mounted to rotate, so that winding or unwinding of the carrier material is facilitated, particularly in the over-pressed state, upon contact with the roller surface.

[0051] According to another embodiment, preferably according to configuration b), the pressure element is designed as the brush body of the brush.

[0052] According to another embodiment, the carrier material is heat-resistant up to at least 150°C. This allows cleaning to take place during ongoing production, preferably during the manufacture of electrode material for accumulators, particularly for cleaning calender rollers in anode and / or cathode foil production, thus eliminating all downtime for cleaning.

[0053] According to another embodiment, the thickness of the carrier material is between 0.1 and 0.8 mm. The thinner the material chosen, the lower its absorbency becomes, while the wound-up cloth length increases and the winding diameter remains the same.

[0054] Another important component of the device is the humidification unit. According to one embodiment, the humidification unit is designed as an external pumping station with one or more pumps, preferably piston pumps, and one or more plastic lines with spray channels in the cleaning device. The external pumping station uses the one or more piston pumps to deliver a mixture through plastic lines into the device, up to the spray channel. The lines are then under controlled overpressure. The amount of the sprayed mixture is metered via controllable valves in or on the spray channel or the pressure element. According to one embodiment, the one or more spray channels are located in the pressure element.

[0055] According to another embodiment, the humidification device is designed as a tank connected to an opening, preferably a slot, in the pressure element. With this concept for metering the mixture into the carrier material, the humidification device is designed as an opening, preferably a slot, in the pressure element, wherein the carrier material, according to embodiment a), is brushed over the opening and humidification occurs through the absorbency (capillary action) of the carrier material, preferably the fibers. This humidification device can be filled by tanks located in the cleaning device or by a pump station.

[0056] According to another embodiment, the winding spindle and / or the unwinding spindle are driven, preferably by a motor or manually. For this purpose, one or more motors and / or one or more handles are incorporated into the device. This allows the carrier material to be wound or unwound in both directions. A further advantage is that the carrier material can continue to move even when the spindle is in a fixed position, despite pressure and relative forces from the roller surface. This function is an important feature for continuous cleaning, because otherwise, changing the cloth would require an interruption of the cleaning contact, leaving a dirt edge on the roller surface. This dirt edge would then be deposited on the producing film, rendering it unusable.

[0057] According to another embodiment, the brush is designed as a carrier material to perform a rotational movement and / or lateral movements, preferably by a motor.

[0058] If an area of ​​the carrier material remains in contact with the soiled surface for an extended period, for example, for two full roller rotations, it is advisable to add more of the mixture to re-moisten the carrier material and / or to bring a fresh, unused area of ​​the carrier material into contact with the surface. Winding the carrier material onto the winding spindle transports the soiled area away from the roller surface. This transport is achieved by rotating the winding spindle. The so-called dirt cloth spindle (also called the winding spindle) is driven in this case, while the unwinding spindle is preferably braked mechanically or electrically to ensure the carrier material remains taut.

[0059] Another feature of the device is its heat-resistant design, achieved through the use of shielding plates, temperature-stable electronic components such as sensors and connectors, specially shielded cables and hoses, and active cooling elements like fans and radiators. The substrate material must also be heat-resistant, which is accomplished through a mixture of appropriate plastics and natural fibers. According to another embodiment, the surface cleaning device is housed in a casing that is heat-resistant up to 150°C. Another embodiment provides for the device to include fans and / or radiators for active cooling.

[0060] According to a further aspect of the present invention, a device for the production of electrode material for accumulators, in particular for the production of anode and / or cathode foils, is proposed, comprising two or more rollers, preferably calender rollers, wherein the device has one or more devices for cleaning the two or more rollers according to one of the aforementioned embodiments.

[0061] According to another embodiment of the device for producing electrode material for accumulators, the device comprises further rollers, preferably guide rollers, which also come into contact with the respective battery pastes during the manufacturing process of electric batteries and become contaminated, wherein the device has one or more devices for cleaning the further rollers according to one of the aforementioned embodiments.

[0062] According to another embodiment of the device for producing electrode material for accumulators, the cleaning device according to one of the aforementioned embodiments is attached to a component that moves in relation to the movable calender roll in the case of vertically movable calender rolls, thus enabling a continuous contact point, regardless of the vertical position of the calender roll.

[0063] The cleaning device, according to one of the aforementioned embodiments, incorporates an automatic unit in the calender for the production of electrode material for accumulators. This unit moistens the substrate material with a mixture and presses it against the calender rolls, preferably across the entire usable width. The rotation of the rolls then provides mechanical, chemical, and temperature-controlled cleaning of the surface. The usable width is understood to be at least the maximum width of the film web coated with battery paste; however, it typically covers the largest possible width of the calender rolls, as determined by the design.

[0064] According to another embodiment, the cleaning device, as described in one of the aforementioned embodiments, is movable within the device for manufacturing electrode material for accumulators and can be moved towards or away from the roller surface. Preferably, the device includes a device movement unit designed to move the cleaning device towards and away from the roller surface. This allows the carrier material to be actively moved towards or away from the roller surface via the device movement unit, thereby establishing or ceasing contact between the carrier material and the surface to be cleaned.

[0065] According to another embodiment, the cleaning device according to one of the aforementioned embodiments can be designed to be movable relative to one of the rollers, thus allowing the cleaning device to be moved towards or away from the surface of the roller, thereby enabling the contact between the carrier material and the surface to be cleaned to be switched on or off. Alternatively or additionally, one of the rollers can be designed to be movable relative to the cleaning device according to one of the aforementioned embodiments, so that the surface of the roller can be moved towards or away from the cleaning device, thereby enabling the contact between the carrier material and the surface to be cleaned to be switched on or off.

[0066] It may be provided that the electrodes of the process and / or the device for cleaning surfaces for the manufacture of electrodes are predominantly made of lithium metal oxide, and / or sodium metal oxide, and / or another alkali metal metal oxide, and / or graphite, and / or another material.

[0067] The following are examples of embodiments which may supplement and / or replace the embodiments described above.

[0068] A method for cleaning surfaces in the production of electrode material for accumulators is proposed, particularly for cleaning calender rollers in the production of anode and cathode foils. The essential aspect of this method is that a suitable carrier material is moistened with a suitable mixture, pressed against the roller, and the contaminants are removed from the carrier material and surface by relative movement.

[0069] According to another embodiment, the suitable liquid for cleaning deposits from cathode production consists of a mixture of at least one ester and / or polyvalent alcohol (glycol) and / or glycol ether and / or long-chain alcohol and / or a possible combination of all the aforementioned substances.

[0070] According to another embodiment, a specific selection from the aforementioned substances is used which has sufficient resistance to the materials used in the system and at the same time meets the production conditions with regard to evaporation and temperature stability.

[0071] According to another embodiment, the mixture consists partly or exactly of the substances triethyl citrate, propylene glycol and butyl glycol.

[0072] According to another embodiment, the support material is stretched on a plastic surface which is pressed against the rotating roller surface, so that the support material lies between the plastic surface and the roller surface and the relative movement is thereby depicted.

[0073] According to another embodiment, the carrier material can be moistened from the direction of the plastic surface via a spray or application system.

[0074] According to another embodiment, the carrier material consists of a knitted, lint-free cloth.

[0075] According to another embodiment, the carrier material can be actively moved against the roller surface via a traversing unit, thus switching on or off the contact between the carrier material and the surface to be cleaned.

[0076] According to another embodiment, the suitable liquid for cleaning deposits from anode production consists of a mixture of at least deionized water and an alcohol and / or glycol and / or glycol ethers, in order to modify the evaporation properties. According to another embodiment, the already water-containing mixture is further diluted with deionized water in a mixing ratio of 100:1 to 1:100.

[0077] According to another embodiment, the evaporation properties of the mixtures are adapted so that the production conditions allow continuous cleaning with moistened carrier material without bringing the film web to be produced into contact with residues of the respective mixture.

[0078] According to another embodiment, a cloth is pulled from an unwinding spindle onto a winding spindle and guided over a pressure element, so that the entire width of the cloth is pressed evenly onto the roller surface.

[0079] According to another embodiment, the pressure element is designed to be movable and can be moved towards or away from the roller surface.

[0080] According to another embodiment, a crowning of the roller surface is compensated for by the shape and / or elasticity of the pressure element.

[0081] According to another embodiment, the pressure element is mounted in a rotating manner, so that winding or unwinding of the cloth is facilitated, especially in the overpressed state, when in contact with the roller surface.

[0082] According to another embodiment, the cloth is moistened from within the pressure element.

[0083] According to another embodiment, the cloth is moistened by an integrated tank or intermediate tank through capillary action of the cloth fibers.

[0084] According to another embodiment, the device is installed in a housing that is heat-resistant up to 150°C.

[0085] According to another embodiment, the device is actively cooled by fans and / or radiators. According to another embodiment, the support material is already impregnated with the suitable mixture before it is used in the device.

[0086] According to another embodiment, the carrier material is a microfiber cloth.

[0087] According to another embodiment, the carrier material is heat-resistant up to at least 150°C.

[0088] According to another embodiment, the moistening of the carrier material does not occur from the direction of the pressure element, but from an external dosing system such as an external spray tube.

[0089] According to another embodiment, it is not the surfaces of the calender rolls that are cleaned, but other technical surfaces that also come into contact with the respective battery pastes during the manufacturing process of electric batteries and become contaminated, in particular guide rolls.

[0090] According to another embodiment, in the case of vertically movable calender rolls, the attachment is to a component that moves in relation to the movable calender roll, thus enabling a continuous contact point, regardless of the vertical position of the calender roll.

[0091] The invention will now be described in more detail with reference to the exemplary embodiment shown in the accompanying drawings, in which:

[0092] FIG. 1: Schematic representation of two calender rolls in a calender roll plant with several devices according to the invention for cleaning the calender rolls;

[0093] FIG. 2: Schematic representation of the devices for cleaning the calender rolls from FIG. 1;

[0094] FIG. 3: Table with chemical symbols for the three main components of the mixture for cleaning surfaces in cathode manufacturing. FIG. 1 shows a calender roll plant 1 with an upper calender roll 2 and a lower calender roll 3 to be cleaned. A foil web 8 is guided between the calender rolls 2 and 3 for calendering. The foil web 8 of FIG. 1 can be used for cathode production or anode production.

[0095] As shown in FIG. 1, the upper calender roll 2 is assigned a first and second cleaning device 4 and 5 of the roll. Likewise, the lower calender roll 3 is assigned a third and fourth cleaning device 6 and 7.

[0096] In the embodiment shown in FIG. 1, the film web 8 is moved from right to left through the calender roll assembly 1. Due to this production direction, the first cleaning device 4 is located on the exit side of the upper calender roll 2, i.e., the side of the roll that first comes into contact with the cleaning device 4 after the film web 8 has been calendered. The second cleaning device 5 is located on the entry side of the upper calender roll 2, i.e., the side of the roll that moves towards the film web 8. As the upper calender roll 2 rotates clockwise, a carrier material 13 of the first and second cleaning devices 4 and 5 unwinds clockwise as needed to prevent a dirt edge from forming on the surface of the roll.

[0097] Accordingly, due to the production direction shown in FIG. 1, the third cleaning device 6 is assigned to the lower calender roll 3 on its exit side, i.e., the side of the roll that first comes into contact with the third cleaning device 6 after the film web 8 has been calendered. The fourth cleaning device 7 is assigned to the lower calender roll 3 on its entry side, i.e., the side of the roll that moves towards the film web 8. Due to the counterclockwise rotation of the lower calender roll 3, a carrier material 13 of the third and fourth cleaning devices 6 and 7 unwinds counterclockwise as needed to prevent a dirt edge from forming on the surface of the roll.

[0098] The first cleaning device 4, as shown in FIGS. 1 and FIGS. 2, comprises an unwinding spindle 10, a winding spindle 9, a pressure element 11, a moistening device 12, and a carrier material 13. The carrier material 13 is pulled from the unwinding spindle 10 to the winding spindle 9 and is thereby tensioned over the pressure element 11. The unwinding spindle 10 and / or the winding spindle 9 can be driven by a motor or mechanically, or braked by a motor or mechanically.

[0099] The pressure element 11 is designed to press the carrier material 13 against the upper calender roll 2. In the embodiment shown in FIG. 1, the pressure element 11 can be designed as a plastic surface or a rubber strip.

[0100] In the embodiment shown in FIGS. 1 and FIGS. 2, the humidification device 12 is designed as a slot in the pressure element 11, which is connected to a tank (not shown) containing a mixture for humidifying the carrier material 13. Due to this concept for metering the mixture into the carrier material 13, the humidification device 12 is designed as a slot in the pressure element 11, whereby the carrier material 13 is slid over the slot and humidification occurs due to the absorbency (capillary action) of the carrier material 13.

[0101] For clarity, FIGS. 1 and 2 show a gap between the pressure element 11, the carrier material 13, and the upper calender roll 2. This gap is included in the figures solely for the sake of clarity. As previously described, when in use, the carrier material 13 is pressed against the pressure element 11 by tension between the unwind spindle 10 and the wind-up spindle 9. Furthermore, when using the first cleaning device 4, the carrier material 13 is pressed against the upper calender roll 2.

[0102] The second, third and fourth cleaning devices 5, 6 and 7 of FIG. 1 are identical to the first cleaning device 4 of FIG. 1 and FIG. 2.

[0103] FIG. 3 shows a table with the chemical symbols of the three main components of an embodiment of the mixture for cleaning surfaces in cathode manufacturing. These are a) triethyl citrate, b) propylene glycol, and c) butyldiglycol. A particularly effective cleaning mixture for cathode manufacturing can be produced from these components. In a preferred embodiment that does not require labeling, components from group c) are mixed to a maximum of 10% of the total solution. The remaining 90% of the total solution is mixed from groups a) and b) in any desired ratio. Reference numeral list

[0104] 1 calender roll plant

[0105] 2 Calender roller top

[0106] 3 Calender roller bottom

[0107] 4. First device for cleaning

[0108] 5 second device for cleaning

[0109] 6. Third cleaning device

[0110] 7 fourth device for cleaning

[0111] 8 foil strips

[0112] 9 winding spindle

[0113] 10 Unwinding spindle

[0114] 11 Pressure element

[0115] 12 Humidification unit

[0116] 13 Carrier material

Claims

Patent claims 1. Method for cleaning surfaces for the production of electrode material in accumulators, in particular for cleaning calender rolls (2, 3) in the production of anode and / or cathode foils, which is characterized by the fact that a carrier material (13) is moistened with a mixture, pressed against a roll (2, 3) and an impurity is removed by relative movement of the carrier material (13) and the surface of the roll (2, 3), preferably from the surface of the roll (2, 3).

2. Method according to claim 1, dadu rc hge ke nn ze ichn et, that the cleaning takes place during ongoing production, preferably during the manufacture of electrode material for accumulators, in particular the cleaning of calender rolls (2, 3) during anode and / or cathode foil production.

3. Method according to one of claims 1 or 2, which is characterized by the fact that the carrier material (13) is a cloth, fabric, textile, nonwoven, sponge of both artificial and natural origin, elastomer or thermoplastic structural material, preferably a knitted lint-free cloth, preferably a microfiber cloth.

4. Method according to claim 3, dadu rc hge ke nn ze ichn et, that the carrier material (13) is stretched on a plastic surface or rubber strip which is pressed against the rotating surface of the roller, so that the carrier material (13) lies between the plastic surface or rubber strip and the roller surface.

5. Method according to claim 4, dadu rc hge ke nn ze ichn et, that the carrier material (13) is moistened from the direction of the plastic surface or the rubber strip via a moistening device (12).

6. Method according to one of claims 3 to 5, dadu rc hge ke nn ze ichn et, that the carrier material (13) is unwound from an unwinding spindle (10) onto a winding spindle (9), so that the need for fresh carrier material (13) can be controlled and dosed.

7. Method according to one of claims 1 to 5, dadu rc hge ke nn ze ichn et, that ss als Trägermaterial (13) eine Brush wird.

8. Method according to claim 6, dadu rc hge ke nn ze ichn et, that the brush rotates for cleaning and / or performs side movements.

9. Method according to one of claims 1 to 7, which means that the carrier material (13), preferably via a traversing unit, is actively moved against the surface of the roller (2, 3) or away from the surface of the roller (2, 3), thereby switching on or off the contact between the carrier material (13) and the surface to be cleaned, and / or the roller (2, 3) is actively moved against the carrier material (13) or away from the carrier material (13), thereby switching on or off the contact between the carrier material (13) and the surface to be cleaned.

10. Method according to one of claims 1 to 8, which indicates that by means of a constant contact pressure over a defined time the contamination is transferred from the surface of the roller (2, 3) into the carrier material (13).

11. Method according to one of claims 1 to 9, which indicates that the surface of the roller (2, 3) is cleaned by alternating cycles with moistened and dry carrier material (13).

12. Method according to one of claims 1 to 10, which indicates that the purification is carried out via the polarity of the mixture, preferably without a chemical reaction.

13. Method according to one of claims 1 to 11, which indicates that the moistening of the carrier material (13) takes place from within a pressure element (11) or the brush, and / or the carrier material (13) has already been impregnated with the mixture before it is used, and / or the moistening of the carrier material (13) takes place from an external metering system, preferably an external spray tube, preferably not from the direction of a pressure element (11).

14. Method according to one of claims 1 to 12, which indicates that color particles are added to the mixture to detect the spray distribution of the mixture on and / or in the carrier material (13) before moistening the carrier material (13).

15. Mixture for cleaning surfaces for the production of electrode material in accumulators, in particular for cleaning calender rolls (2, 3) in cathode foil production, dadu rc hge ke nn ze ichn et that the mixture has at least one ester, and / or polyvalent alcohol, and / or glycol, and / or glycol ether, and / or long-chain alcohol or a possible combination of several or all of the aforementioned substances, preferably consisting of.

16. Mixture according to claim 14, dadu rc hge ke nn ze ichn et, that the mixture contains, or preferably consists of, the substances triethyl citrate, propylene glycol and butyldiglycol.

17. Mixture according to claim 14 or 15, which means that the mixture comprises or consists of components of the following three groups: a) 1,2-propanediol (1,2-propylene glycol); b) triethyl citrate (triethyl citrate); c) butyldiglycol (systematically: 2-(2-butoxyethoxyethanol), preferably in a ratio of 0.1% to 10% from group a) and the remainder from groups b) and / or c).

18. Mixture for cleaning surfaces for the production of electrode material in accumulators, in particular for cleaning calender rolls (2, 3) in anode foil production, dadu rc hge ke nn ze ichn et that the mixture has at least deionized or distilled water and an alcohol and / or glycol and / or glycol ethers, preferably consisting of these, in order to change the evaporation properties.

19. Mixture according to claim 17, dadu rc hge ke nn ze ichn et, that the already water-containing mixture is further diluted with deionized water in a mixing ratio of 100:1 to 1:

100.

20. Mixture according to one of claims 14 to 18, which indicates that the evaporation point of all components of the mixture is adapted to the present temperature range, preferably + / - 10°C, of ​​the roller (2, 3).

21. Mixture according to one of claims 14 to 19, dadu rc hge ke nn ze ichn et, that the evaporation property of the mixture is adapted so that the conditions of production enable continuous cleaning with moistened carrier material (13) without bringing a film web (8) to be produced into contact with residues of the respective mixture.

22. Mixture according to one of claims 14 to 20, dadu rc hge ke nn ze ichn et, that the mixture contains additional color particles.

23. Method according to one of claims 1 to 13, dadu rc hge ke nn ze ichn et, that one of the mixtures of claims 14 to 21 is used for purification.

24. Device for cleaning (4, 5, 6, 7) surfaces for the production of electrode material in accumulators, in particular for cleaning calender rolls (2, 3) in the production of anode and / or cathode foils, comprising a pressure element (11), a humidification device (12) and a carrier material (13), wherein the pressure element (11) is used for The device is configured to press the carrier material (13) against a roller surface, and wherein the moistening device (12) is configured to moisten the carrier material (13), and a) that the carrier material (13) is configured as a cloth, fabric, textile, nonwoven, sponge of both artificial and natural origin, elastomer or thermoplastic structural unit, and the device further comprises an unwinding spindle (10) and a winding spindle (9), wherein the carrier material (13) is drawn from the unwinding spindle (10) to the winding spindle (9) and is thereby tensioned over the pressing element (11), or b) that the carrier material (13) is configured as a brush.

25. Device for cleaning (4, 5, 6, 7) according to claim 23, which indicates that the entire width of the carrier material (13) is pressed evenly onto the roller surface by the pressure element (11).

26. Device for cleaning (4, 5, 6, 7) according to claim 23 or 24, which indicates that the device has a traversing unit which is designed to move the pressure element (11) in such a way that the pressure element (11) can be moved towards or away from the roller surface.

27. Device for cleaning (4, 5, 6, 7) according to one of claims 23 to 25 with a carrier material according to embodiment a), dadu rc hge ke nn ze ichn et that the pressure element (11) has a curved surface for guiding the carrier material (13), and / or the pressure element (11) or at least a guide surface of the pressure element (11) is elastically designed.

28. Cleaning device (4, 5, 6, 7) according to one of claims 23 to 26 with a carrier material according to embodiment a), dadu rc hge ke nn ze ichn et, da ss the pressure element (11) is mounted in a rotating manner, so that winding or unwinding of the carrier material (13) is facilitated, especially in the overpressed state when in contact with the roller surface.

29. Cleaning device (4, 5, 6, 7) according to one of claims 23 to 25 with a carrier material according to embodiment b), dadu rc hge ke nn ze ichn et, that ss the pressure element (11) is designed as the brush body of the brush.

30. Device for cleaning (4, 5, 6, 7) according to one of claims 23 to 28, dadu rc hge ke nn ze ichn et, that the carrier material (13) is heat-resistant up to at least 150°C.

31. Cleaning device (4, 5, 6, 7) according to one of claims 23 to 29, that the humidification device (12) is designed as an external pumping station with one or more pumps, preferably piston pumps, and one or more plastic lines with a spray channel in the cleaning device.

32. Device for cleaning (4, 5, 6, 7) according to one of claims 23 to 30, which indicates that the humidification device (12) is designed as a tank connected with an opening in the pressure element (11), wherein preferably with a carrier material (13) according to embodiment a) the carrier material (13) is slipped over the opening and humidification takes place through the absorbency (capillary action) of the carrier material (13).

33. Device for cleaning (4, 5, 6, 7) according to one of claims 23 to 31 with a carrier material according to embodiment a), dadu rc hge ke nn ze ichn et that ss the winding spindle (9) and / or the unwinding spindle (10) are designed to be driven, preferably each by a motor.

34. Cleaning device (4, 5, 6, 7) according to one of claims 23 to 25 and 28 to 32 with a carrier material according to embodiment b), dadu rc hge ke nn ze ichn et, that ss that the brush as carrier material (13) is designed to be driven in order to perform a rotational movement and / or lateral movements, preferably by a motor.

35. Cleaning device (4, 5, 6, 7) according to one of claims 23 to 33, dadu rc hge ke nn ze ichn et, that ss this is installed in a housing that is heat-resistant up to 150°C.

36. Cleaning device (4, 5, 6, 7) according to one of claims 23 to 34, dadu rc hge ke nn ze ichn et that the device has fans and / or radiators for active cooling.

37. Device for the production of electrode material for accumulators (1), in particular for the production of anode and / or cathode foils, comprising two or more rollers (2, 3), preferably calender rollers (2, 3), wherein the device has one or more devices for cleaning the two or more rollers (2, 3) according to one of claims 23 to 35.

38. Device (1) according to claim 36, dadu rc hge ke nn ze ichn et, that the device comprises further rollers, preferably guide rollers, which also come into contact with the respective battery pastes during the manufacturing process of electric batteries and become contaminated, wherein the device has one or more devices for cleaning the further rollers according to one of claims 23 to 35.

39. Device (1) according to claim 36 or 37, dadu rc hge ke nn ze ichn et, da ss The cleaning device (4, 5, 6, 7) according to one of claims 23 to 35 is attached to a component in the case of vertically movable calender rolls (2, 3) which moves in relation to the movable calender roll (2, 3) and thus enables a continuous contact point, regardless of the vertical position of the calender roll (2, 3).

40. Device (1) according to claims 36 to 38, characterized in that the cleaning device (4, 5, 6, 7) according to one of claims 23 to 35 is designed to be movable relative to one of the rollers, so that the cleaning device (4, 5, 6, 7) can be moved towards the surface of the roller (2, 3) or moved away from the surface of the roller (2, 3), thereby enabling the contact between the carrier material (13) and the surface to be cleaned to be switched on or off, and / or one of the rollers is designed to be movable relative to the cleaning device (4, 5, 6, 7) according to one of claims 23 to 35, so that the surface of the roller (2, 3) can be moved towards the cleaning device (4, 5, 6, 7) or moved away from the cleaning device (4, 5, 6, 7), thereby enabling the contact between the carrier material (13) and the surface to be cleaned to be switched on or off. The surface can be switched on or off.

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