Device and method for the heat treatment of a film as well as heat treatment system

Abstract

A device for heat-treating a film (14) comprises a first irradiation unit (16) configured to irradiate the film (14) to heat it, and a first tempering roller (18) having a first cladding surface (18A) for contact with a first side of the film (14). The first tempering roller (18) is arranged to deflect the film (14) over the first cladding surface (18A). The first cladding surface (18A) is configured to temper the film (14). The first irradiation unit (16) is arranged opposite the first cladding surface (18A) to irradiate a second side of the film (14) along a section of the film (14) that is in contact with the first cladding surface (18A).

Description

Technical field

[0001] This disclosure relates to a device for the heat treatment of a film, comprising a first radiant unit configured to irradiate the film in order to heat the film.

[0002] This disclosure further relates to a method for the heat treatment of a film, in which the film is irradiated in order to heat it.

[0003] Finally, this disclosure relates to a heat treatment system comprising the device for heat treating a film as well as the film itself. State of the art

[0004] Well-known infrared emitters are used for heating and drying goods in a wide variety of industrial manufacturing processes. An infrared emitter with a casing tube and a heating element arranged within it is known, for example, from DE 10 2011 108 421 B3.

[0005] Such infrared emitters can be used, for example, in processes often referred to as "baking" or "post-drying." These are used, for instance, in the production of lithium-ion batteries to reduce the manufacturing-related water content of the electrodes (from several thousand to 200 ppm) or in the production of sodium-ion batteries to precisely control the water of crystallization content in the active materials (e.g., Prussian blue analogs).

[0006] One method involves placing a roll of film coated with an active material into a vacuum chamber. Applying a vacuum then removes moisture from the active layer. A moisture content of 100 ppm is desirable. Before the drying process, the water content is typically around 2000 ppm. This drying process usually requires a holding time of more than 24 hours to achieve the desired effect.

[0007] Alternatively, a roll-to-roll process can be used. In this process, the battery material is heated to reach the necessary drying temperature. Technical task

[0008] The present disclosure is based on the technical problem of providing a device and a method with which the heat treatment of a film can be improved. Summary of Revelation

[0009] According to a first aspect, a device for the heat treatment of a film is provided, comprising a first radiant unit and a first tempering roller. The first radiant unit is configured to irradiate the film in order to heat it. The first tempering roller has a first lateral surface for contact with a first side of the film. The first tempering roller is arranged to deflect the film over the first lateral surface. The first radiant unit is configured to temper the film. The first radiant unit is arranged opposite the first lateral surface to irradiate a second side of the film along a section of the film that is in contact with the first lateral surface.

[0010] According to a second aspect, a heat treatment system is provided, comprising the device for heat-treating a film as described herein and the film itself. The film optionally has a substrate and a first coating. The first coating is applied to the substrate on at least the second side. Coating the substrate on both sides is also possible.

[0011] According to a third aspect, a method for the heat treatment of a film is provided, which includes the following steps: a) deflecting and simultaneously tempering a first side of the film by means of a first tempering roller and b) irradiating a second side of the film along a section of the film that is deflected by the first tempering roller in order to heat the film.

[0012] In an optional embodiment, the first temperature control roller comprises metal, optionally stainless steel, copper and / or aluminum.

[0013] In an optional embodiment, the first temperature control roller has a temperature control device for temperature control of the first outer surface, wherein optionally the temperature control device has a cavity that can be filled with a temperature control fluid.

[0014] In an optional embodiment, the device is designed to deflect the film by more than 90°, optionally more than 120°, and further optionally by 180°, through the first tempering roller.

[0015] In an optional embodiment, the first temperature control roller has a diameter greater than 50 cm.

[0016] In an optional embodiment, the device further comprises an airtight chamber, wherein the first radiant unit and the first temperature control roller are arranged in the chamber.

[0017] In an optional embodiment, the device further comprises a pumping device configured to generate a negative pressure, optionally a vacuum, in the chamber, and / or the device further comprises a drying device configured to maintain a gas in the chamber at a dew point temperature below 0°C.

[0018] In an optional embodiment, the device comprises a drive and a control unit, wherein the drive is optionally configured to move the film over the first tempering roller. Optionally, the control unit is in data communication with the first emitter unit and the drive to regulate the intensity of the radiation generated by the first emitter unit and the speed of the film's movement.

[0019] In an optional embodiment, the device further comprises a temperature sensor for measuring the temperature of the film, the temperature sensor optionally being in data communication with the controller. Optionally, the controller is further configured to regulate the intensity of the radiation generated by the first emitter unit and / or the speed of movement of the film depending on the temperature of the film.

[0020] In an optional embodiment, the device comprises a second emitter unit configured to irradiate the film in order to heat it, and / or a second tempering roller with a second outer surface for contact with the second side of the film, wherein the second tempering roller is optionally arranged to deflect the film over the second outer surface. Optionally, the second outer surface is configured to temper the film. Furthermore, optionally, the second emitter unit is arranged opposite the second outer surface in such a way as to irradiate a first side of the film along a section of the film that is in contact with the second outer surface.

[0021] The device, heat treatment system, and process described here can be used for drying the film, thereby reducing the drying time required, as rapid and efficient heating of the film is possible. This is achieved by using the first heating roller to pre-heat the film, thus increasing the power output of the first radiant heating unit. This means that the device, heat treatment system, and process increase the power required to heat the film while simultaneously preventing overheating, which could lead to its destruction or damage. In other words, a gentler drying process is possible.

[0022] The apparatus, heat treatment system, and process described here can be used for the heat treatment of all types of films. The heat treatment can be used for the esterification of materials within the film, for example, the first and / or second coating. Esterification can be carried out as a separate step or as part of the baking process of the film. Such esterification can be performed, for example, on a silicon anode. The silicon anode can be an example of the first and / or second coating. The silicon anode can contain binders that bond with each other through esterification, for example, CMC (carboxymethylcellulose) and PAA (polyacrylic acid).

[0023] For esterification, the film can be heated to 140 °C or more to initiate the chemical reaction. Therefore, esterification does not occur in known vacuum drying systems without heat treatment.

[0024] Esterification can involve the following chemical reaction: A⁻COOH + B⁻OH → A⁻COO-B + H₂O. The water produced during this esterification can evaporate due to the applied heat, allowing the film to be dried simultaneously with the esterification process. Further condensation reactions between components of the first and / or second layer are conceivable. Esterification of the binders in a silicon anode can provide higher mechanical stability. The complex polymer structure holds the silicon particles together like a network and helps to reduce or prevent damage to the electrode layer due to volume changes during charging and discharging.

[0025] Heat treatment can also serve to relieve internal stresses. These stresses would otherwise lead to damage and / or destruction of the cell during the charging and discharging process.

[0026] Heat treatment can also be used for (sole) drying of the film. Drying refers to the removal or reduction of water or water molecules (H₂O) that are in and / or on the film, for example, physically and / or chemically bound to materials within the film. By heating the film, which increases its thermal energy, these physical and / or chemical bonds can be broken, allowing the water molecules to leave the film. As a result, the amount of water or the number of water molecules in and / or on the film can be reduced.

[0027] Optionally, the solution presented here can be used in the production of sodium-ion and / or lithium-ion batteries, for example, in processes known as "baking" or "post-drying." The aim is to reduce the residual water content and / or adjust the water of crystallization content to a precise value in certain active materials arranged on a film (and thus potentially forming part of the first and / or second coating). After drying and / or esterification, the film can be cut to size and used as an electrode in batteries.

[0028] Water of crystallization generally consists of three different types: first, water adsorbed on the surface; second, water physically bound within the crystal or crystalline structure of the active material (e.g., by electrical forces such as van der Waals forces and / or dipole-dipole interactions), so-called zeolitic water (interstitial water); and third, chemically coordinated water. By precisely controlling the temperature of the film and thus the active layer through a combination of the first radiation unit and the first temperature control roller, the unwanted release of, for example, coordinated water can be prevented.

[0029] The device, heat treatment system, and process described here can be used in a roll-to-roll process. The film can be coiled before heat treatment (e.g., drying and / or esterification), also known as coiling. The film is then unwound and guided over the first tempering roller past the first radiant heating unit. The heat-treated film can then be rewound. It is possible for the film to be guided over one or more deflection rollers and / or one or more additional tempering rollers past further radiant heating units.

[0030] The use of a roll-to-roll process can achieve a significant reduction in drying time compared to a drying method where the wound film is placed in a vacuum chamber for often more than 24 hours. Furthermore, the expulsion of moisture from the wound film can be detrimental to its subsequent processing, a problem avoided with the solution described here. A film wound during drying exhibits a curl that can hinder further processing steps, including battery production.

[0031] The film can be a homogeneous sheet made of a thin material or material combination. It can be a ribbon-like, flexible, and / or rollable product. The film can have a thickness between 1 µm and 1 cm, optionally between 2 µm and 1000 µm. The film width can be between 20 cm and 5 m, optionally between 50 cm and 3.5 m. The film length can be between 1 m and 2500 m, optionally between 500 m and 1500 m.

[0032] For example, the substrate has a thickness of 1 µm to 20 µm, optionally 2 µm, and the first and second coatings together have a thickness of 300 µm to 700 µm, optionally 500 µm. The first coating and / or the second coating each have a thickness of 20 µm to 500 µm, optionally 60 µm to 200 µm.

[0033] The film can be used to create an electrode layer. For example, the electrodes for batteries are cut from the film. The film can have a substrate or carrier material, which may include metal (such as aluminum or copper) and / or plastic, as well as a first coating and / or a second coating. The substrate may be designed to provide the film with mechanical stability, allowing the first coating and / or second coating to be applied to it. The carrier material or substrate can also serve to conduct electricity or electrons along the film, for example, in the battery cell.

[0034] The first and / or second coating can each comprise several successively applied layers; for example, a so-called primer layer can be applied beneath the actual electrode. This serves to increase conductivity and adhesion. The first and / or second coating can be the active material and / or the active layer, as described above. Therefore, the drying of the film may aim to reduce or adjust the water content only in the first and / or second coating. Drying of the substrate or the support material may not be necessary, as the water content in the substrate and / or the support material is not critical for the film's function and / or little or no water is bound in the substrate or the support material.

[0035] The first coating can be applied to the second side of the film. This can mean that the first coating is applied to a second side of the substrate or carrier material. The second coating can be applied to a first side of the film. This can also mean that the second coating is applied to a first side of the substrate or carrier material. The second side can be positioned opposite the first side. This means that when the film is in contact with the first tempering roller via the first side, the second side of the film is irradiated by the first radiant unit.

[0036] The first coating can be applied to the substrate as a so-called slurry. The slurry can be pre-dried before the film is further dried and / or esterified using the device described here. Therefore, the drying process carried out with the device described here can be referred to as "post-drying." "Baking" can be considered "post-drying" through heating.

[0037] The first emitter unit can comprise one or more emitters designed to emit electromagnetic radiation to heat the film. The one or more emitters can include infrared emitters.

[0038] Infrared emitters can be designed to emit radiation in the infrared spectral range. They may have a casing tube containing a heating element, such as a carbon heating band or a heating coil made of tungsten, molybdenum, tantalum, niobium, and / or an alloy of these elements. The casing tube protects the heating element from mechanical and / or thermal stresses. It may be filled with a protective gas, such as halogen, to prevent reaction with atmospheric components. The infrared emitter may also include an infrared (IR) LED.

[0039] Known infrared emitters can be classified according to their main emission wavelength into short-wave, medium-wave, and long-wave infrared emitters. The main emission wavelengths of short-wave infrared emitters are in the range of 0.78 µm to 1.4 µm (= IR-A, rated temperature 1,800°C - 3,450°C, according to IEC 62798:2014, Section 4, Classification of infrared emitters by spectral emission, Table 1), medium-wave infrared emitters in the range above 1.4 µm to 3 µm (= IR-B, 690°C - 1,800°C), and long-wave infrared emitters in the range above 3 µm to 1 mm (= IR-C, < 690°C).

[0040] The selection of a suitable emitter for the first emitter unit can be based on the film material, the type of bound water (i.e., zeolitic and / or chemically bound water), and / or the energy required by the first emitter unit. For example, the first emitter unit is selected to heat the film as quickly as possible to a temperature at which surface-adsorbed water and / or zeolitic bound water evaporates, while chemically bound water remains bound. Chemically bound water can be important for maintaining the structure of the film, particularly the active layer.

[0041] The film, optionally the first and / or second coating, can have a water content of 200 ppm (parts per million) to 1000 ppm before drying, which can be reduced to 20 ppm to 350 ppm, or optionally 200 ppm, through drying. The remaining water may be chemically bound. The values ​​mentioned here can be applied to the drying process in the active material for lithium-ion batteries. This water is usually not water of crystallization, but rather residues from the manufacturing process using aqueous solution or from the sorption of water from the air.

[0042] Chemically bound water can be present in the active material (analogs of Prussian blue) used in sodium-ion batteries. Here, the overall reduction in water content can be, for example, 5-10 wt%.

[0043] The drying process could be accelerated by increasing the energy supplied by the first radiant unit. This can be achieved by increasing the emission power of the first radiant unit. However, this could lead to overheating of the film. To prevent this, a first tempering roller is provided. This roller can have heat-dissipating properties. In other words, the first tempering roller, located near the first outer surface, and / or the first outer surface itself, can have a thermal conductivity higher than that of the surrounding environment.

[0044] For example, the thermal conductivity of the first cooling roller at or near its outer surface can be between 20 W / (m*K) and 250 W / (m*K), or optionally between 50 W / (m*K) and 230 W / (m*K). This can be achieved, for example, by making the first cooling roller metal, such as aluminum or steel (stainless steel). The outer surface of the first roller can also be made of metal to ensure good heat dissipation from the foil to the first cooling roller. Alternatively, the outer surface of the first roller can have a coating made of a material with high thermal conductivity. If the coating is made of a material with low thermal conductivity, it can be thin to ensure good thermal conductivity through the coating.

[0045] By adjusting the radiation output applied by the first emitter unit (which heats the film) and the heat dissipation by the first temperature control roller, an equilibrium can be established, allowing a target temperature to be reached. As explained above, this target temperature can lead to the evaporation of zeolitic water, but not to the evaporation of chemically bound water.

[0046] The first temperature control roller can be understood as a device for dissipating heat from the film and / or cooling it. Dissipating heat counteracts the heating of the film by the first radiant unit. This can lead to more reliable temperature control and / or faster drying, as the radiant output of the first radiant unit can be increased compared to a situation without cooling by the first temperature control roller. Thus, the film can be brought to the desired target temperature more quickly, thereby accelerating the drying process. Furthermore, the increased radiant output accelerates the drying process, meaning the water loss per unit of time is increased. This is made possible by the first temperature control roller because otherwise the critical temperature that leads to damage or destruction of the film could be exceeded.

[0047] The first temperature control roller can also be understood as a roller, deflection roller, and / or cooling roller. The first temperature control roller optionally has a cylindrical body. One axis of the cylindrical body can be a rotation axis of the first temperature control roller.

[0048] The first temperature control roller can be mounted on a rotating bearing, so that when the film moves across the first surface, the roller is set into rotation. The first temperature control roller can also be motorized, thus providing the film's feed. Alternatively, the first temperature control roller can be mounted on a non-rotating bearing. In this case, the film can slide across the first surface. For this purpose, the surface can be provided by a coating with a low coefficient of friction.

[0049] The first lateral surface can be the lateral surface of the cylindrical body. The first temperature control roller can be a solid and / or one-piece component made exclusively from a material with high thermal conductivity.

[0050] The first surface of the lateral surface is optionally smooth. The first surface of the lateral surface can extend along a circumferential direction of the first temperature control roller, which is optionally perpendicular to the axis of rotation of the temperature control roller.

[0051] The width of the first surface can correspond to the length of the first tempering roller (which can be measured along the axis of rotation) and to the width of the film. Optionally, the first surface can be wide enough to ensure that the film rests completely on it.

[0052] The first temperature control roller can be understood as a deflection roller, meaning that the direction of expansion or conveying of the film before the first temperature control roller does not coincide with the direction of expansion or conveying after the first temperature control roller. This can be understood as the first temperature control roller not only supporting the film but also deflecting it. This results in an increased contact area between the film and the first roller's outer surface, compared to a situation where the first temperature control roller merely supports the film or—in other words—only makes contact with the film over a small area.

[0053] By redirecting the film using the first tempering roller, the contact area of ​​the film on the first casing surface can be increased, allowing more heat to be transferred from the film to the first tempering roller. This can be used to ensure that the first heating unit irradiates the film over a larger area, thus increasing the film's feed rate. This, in turn, reduces the drying time.

[0054] The energy applied to the film can be increased by having the first emitter unit have several emitters distributed along its surface. Optionally, the first emitter unit is arranged and configured to irradiate the film only in the section where the film is in contact with the first surface. In other words, the first emitter unit is arranged and configured to irradiate the first surface along its circumference in such a section as the film is in contact with the first surface. The first emitter unit can be configured to irradiate only the section of the film that is in contact with the first surface.

[0055] This ensures that the film is only irradiated (and thus heated) where it is in contact with the first temperature control roller and is therefore also tempered or cooled by the first temperature control roller.

[0056] This configuration of the first emitter unit can be achieved by positioning it close to the first temperature control roller. For example, the emitters of the first unit can be arranged along the circumference of the first surface, offset from each other and / or equidistant from the surface. The number of emitters in the first unit and their distance from the surface can be selected such that the electromagnetic energy emitted by each emitter overlaps, optionally enabling homogeneous irradiation of the film. This results in homogeneous heating of the film.

[0057] Furthermore, it is also possible that the first emitter unit has one or more apertures and / or one or more lenses in order to irradiate the first surface and thus the film homogeneously.

[0058] The first emitter unit can be an elongated component whose length corresponds to the width of the film and / or the width of the first lateral surface. An emitter of the first emitter unit can thus apply heat energy to the film across its entire width, but only over a short section along the longitudinal direction of the film and / or the circumferential direction of the first lateral surface.

[0059] The emitter can also be arranged at an angle to the width of the film or perpendicular to the width of the film (i.e., parallel to the longitudinal direction or direction of movement of the film). Several emitters can be arranged equidistantly along the width of the film or along the longitudinal direction of the first tempering roller. The emitter can be straight or curved. For example, the emitter can have a curvature corresponding to the radius of the first tempering roller. In this way, the emitter can maintain a constant distance from the first tempering roller along its circumference.

[0060] The first radiant heating unit cannot therefore be located between the first temperature control roll and any further roll or deflection roll, but only along the circumferential direction of the first temperature control roll. In other words, the first radiant heating unit is only located adjacent to the first temperature control roll. The first radiant heating unit is thus not designed and arranged to heat the film between the temperature control roll and any further roll or deflection roll, but only along the section where the film rests against the first outer surface.

[0061] The temperature control unit can provide active or passive cooling of the first jacket surface. The temperature control unit can include a cooling element that generates cooling in the first temperature control roller, optionally on the first jacket surface.

[0062] In an optional embodiment, the temperature control device can provide cooling and / or temperature control by means of a temperature control fluid. The first temperature control roller can have a cavity adjacent to the first lateral surface, or the wall of which forms the first lateral surface. In other words, the first lateral surface can form a wall of the cavity.

[0063] The cavity can extend along the entire circumference of the first cooling roller and / or the first surface. Alternatively, the cavity can comprise several sections, each extending along the circumference of the first cooling roller and / or the first surface. In both cases, a largely homogeneous cooling of the first surface can be achieved.

[0064] The cavity can be filled with a temperature control fluid, such as a coolant. It is also possible for the temperature control fluid to be continuously pumped through the cavity and cooled to a target temperature outside the first temperature control roller. The temperature control device can therefore also include lines for the temperature control fluid, a pump, and / or a heat exchanger by means of which the temperature control fluid can be heated and / or cooled to a target temperature.

[0065] The temperature control unit can be used to adjust the temperature of the first surface of the film. For example, the temperature of the first surface can be selected so that, in conjunction with the heating by the first radiant unit, the film is raised to a temperature sufficient for zeolite-bound water to evaporate, but not chemically bound water. Furthermore, the temperature can be selected to allow the radiant power to be increased while maintaining a constant film temperature, thus accelerating the drying process without exceeding the critical temperature that would damage or destroy the film.

[0066] The temperature control device thus enables finer temperature adjustment of the film compared to an embodiment in which the first temperature control roller is designed as a passive heat sink. For example, the temperature control device can increase the temperature of the first outer surface relative to room temperature in order to adjust the temperature difference between the first outer surface and the film so that an appropriate amount of heat is transferred from the film to the temperature control roller.

[0067] The properties of the first temperature control roller as a passive heat sink (i.e., without a temperature control device) with regard to heat dissipation can be adjusted by choosing the material of the first temperature control roller and / or the material and / or thickness of the coating.

[0068] The device for heat-treating the film may further comprise one or more deflection rollers, an unwind roller, and / or a rewind roller. The film may be wound onto the unwind roller before heat treatment. After heat treatment, the film may be wound onto the rewind roller or wound onto the rewind roller. The deflection roller may be used to guide the film from the unwind roller to the first tempering roller. Furthermore, the deflection roller may be used to guide the film from the first tempering roller to the rewind roller. The positioning of the one or more deflection rollers, the unwind roller, and / or the rewind roller, relative to the positioning of the first tempering roller, can thus determine the orientation of the film as it approaches the first tempering roller and / or as it exits it (and thus the degree of deflection).The deflection rollers can also be used to cool the film before rewinding it.

[0069] The orientation of the film as it approaches the first tempering roller can be considered the first orientation. The orientation of the film as it moves away from the first tempering roller can be considered the second orientation. The first and / or second orientation can correspond to the direction of movement and / or the longitudinal direction of the film in the respective section.

[0070] The first orientation and the second orientation can enclose an angle α. For example, the angle α can be measured at an intersection of the extensions of the first orientation and the second orientation beyond the first temperature control roller.

[0071] The angle α can be greater than or equal to 90°, optionally greater than or equal to 120°, or optionally 180°, and in any case less than 270°. If the angle α is 90°, in a cross-sectional view the film rests against the first lateral surface over a quarter of its circumference. Thus, the contact area of ​​the film against the first lateral surface can be one quarter of the surface area.

[0072] In the case where the angle α is 180°, the film, in a cross-sectional view, rests against the first lateral surface over half its circumference. Thus, the contact area of ​​the film against the first lateral surface can be half the surface area. It is therefore evident that increasing the degree of deflection of the film by the first tempering roller from 90° to 180° increases the contact area and thus the area over which the first tempering roller tempers the film.

[0073] The first emitter unit can extend along the first lateral surface in the circumferential direction by an angular segment corresponding to the angle α. If the angle α is 90°, the first emitter unit can irradiate one quarter of the first lateral surface in the circumferential direction. If the angle α is 180°, the first emitter unit can irradiate half of the first lateral surface in the circumferential direction.

[0074] The diameter of the first tempering roller can be considered the diameter of its first surface. Since the size of this surface depends on the radius (and therefore on the diameter), using a first tempering roller with a diameter greater than 50 cm increases the surface area of ​​the first roller. This also increases the contact area over which the film rests on the first surface. In this way, the area over which the film is tempered by the first roller can be increased. This, in turn, increases the area irradiated by the first radiant unit. This can be used to move the film faster, thereby accelerating the drying process.

[0075] The diameter of the first temperature control roller can be larger than 20 cm, 30 cm, 40 cm, 50 cm, 60 cm, 70 cm, 80 cm, or 100 cm and / or smaller than 200 cm, 190 cm, 180 cm, 170 cm, 160 cm, 150 cm, 140 cm, 120 cm, or 110 cm. The diameter of the first temperature control roller can be larger than the diameter of the deflection roller, which can be constructed like a conventional deflection roller.

[0076] The chamber can surround the first emitter unit, the first temperature control roller, the winding roller, the unwinding roller, and / or one or more deflection rollers. This can mean that these components are located inside the chamber and are therefore exposed to negative pressure, optionally a vacuum, or to gas with a dew point below 0°C.

[0077] The chamber can include an opening, such as a flap, through which the winding roll can be inserted into the chamber and / or the unwinding roll can be removed from the chamber. The opening, for example the flap, can be sealed airtight with a wall of the chamber. "Airtight" in this context means that it is possible to create a negative pressure, optionally a vacuum, in the chamber, or that the gas in the chamber has a dew point below 0°C.

[0078] The unwinding roller and / or the winding roller can be located outside the chamber. In this case, the chamber can have one or more airlocks through which the film can be fed into or out of the chamber while simultaneously maintaining the pressure (e.g., the vacuum) within the chamber.

[0079] The reduced pressure refers to the atmospheric pressure outside the chamber. In a reduced pressure, or optionally a vacuum, there are fewer gas molecules compared to atmospheric pressure. This results in a lower gas pressure compared to atmospheric pressure, which facilitates the transition of liquid water present in the film into vapor. Therefore, by reducing the pressure in the chamber compared to atmospheric pressure, the drying of the film can be accelerated. Furthermore, the continuous pumping out of the chamber to create the reduced pressure, or optionally a vacuum, promotes the removal of water vapor from the film, which in turn accelerates the drying process.

[0080] To generate the negative pressure, or optionally the vacuum, a pumping device can be provided that is in gas communication with the chamber. The pumping device can have one or more pumps designed to draw gas out of the chamber.

[0081] The dew point temperature, also called the dew point, is the temperature at which the moisture contained in a volume of air or gas condenses and forms a film of water (dew) on solid surfaces when the air cools at constant pressure. Using a gas with a dew point temperature below 0 °C, therefore, similar to using a vacuum, causes the liquid water bound in the film to evaporate, thus drying the film.

[0082] The air drying system can include one or more dehumidifiers and / or one or more pumps. The dehumidifier serves to absorb water vapor from the air, thereby drying the air and lowering the dew point temperature. The one or more pumps create air circulation between the chamber and the dehumidifier(s) to remove the water vapor produced during the drying process.

[0083] Furthermore, the air drying device can have one or more gas tanks filled with a dried gas mixture, for example, air at the desired dew point temperature. The dried gas mixture can be continuously introduced into the chamber to maintain the dew point temperature in the chamber at the desired value. It is also possible to use a pure gas, such as nitrogen, instead of a gas mixture.

[0084] The dew point temperature is optionally less than 0 °C, -5 °C, -10 °C, -15 °C, -20 °C, -25 °C, -30 °C, -35 °C, -40 °C, or -45 °C.

[0085] The drive system comprises one or more motors, for example electric motors, designed to rotate one or more deflection rollers, the unwind roller, the rewind roller, and / or the first temperature control roller. For example, each roller may be assigned its own electric motor to drive that specific roller.

[0086] The controller can have one or more processors and a data storage device. The one or more processors can be configured to execute programs, algorithms, and / or software stored on the data storage device. The controller can communicate with the drive system, for example, the motors, the pump unit, the first radiant unit, and / or the drying unit, in order to control them.

[0087] For example, the control system can be used to synchronize the drive speed of the electric motors of the respective rollers to ensure a uniform advance of the film over the rollers. The control system can also be used to regulate the radiation output of the first emitter unit and synchronize it with the film advance speed to bring the film to the desired temperature.

[0088] The temperature sensor can be a non-contact sensor for measuring the film's temperature. The temperature sensor can include a pyrometer and be located near the first tempering roller. The control system can regulate the film feed rate and / or the radiation output of the first radiator unit to maintain a constant film temperature, for example, at the target temperature.

[0089] The second emitter unit can have the same optional features, embodiments, and / or characteristics as the first emitter unit. The second emitter unit can be structurally identical to the first. Only the arrangement of the second emitter unit can differ from that of the first. The first emitter unit is assigned to the first temperature control roller, and the second emitter unit is assigned to the second temperature control roller.

[0090] The second emitter unit can differ from the first emitter unit, for example, in terms of the type and number of emitters used, power density, and / or material. This allows the parameters for tempering the film to be selected and / or set differently for the first and second emitter units.

[0091] The second tempering roller can have the same optional features, embodiments, and / or characteristics as the first tempering roller. The second tempering roller can be structurally identical to the first. Only the arrangement of the second tempering roller can differ from that of the first. The second tempering roller can be arranged so that the film comes into contact with the second surface of the roller via the second surface, allowing the first side of the film to be irradiated by the second emitter unit. This makes it possible to irradiate and thus dry the film from both sides.

[0092] The first temperature control roller can be positioned opposite the second, and both rollers deflect the film by 180°. The first and second rollers can be positioned close together because the film is heat-treated along the circumference of the rollers. This allows the film length between the rollers to be kept short. This arrangement differs from known methods where the film is dried between deflection rollers. In those methods, the diameter of the deflection rollers can be smaller than the diameter of the first and / or second temperature control rollers, and the distance between the deflection rollers can be greater than the distance between the first and second rollers.

[0093] The device may further comprise a third, fourth, fifth, or additional temperature control rollers with an associated radiant unit. These may be constructed like the first and / or second temperature control roller or like the first and / or second radiant unit. Example of implementation

[0094] The disclosure is explained in more detail below with reference to exemplary embodiments and drawings. Specifically, the following is shown schematically: Fig. 1 a cross-sectional view of a first embodiment of a heat treatment system for the heat treatment of a film; Fig. 2 a cross-sectional view of a second embodiment of a heat treatment system for the heat treatment of a film; Fig. 3 a cross-sectional view of a third embodiment of a heat treatment system for the heat treatment of a film; Fig. 4 a cross-sectional view of a section of the film; and Fig. 5 A block diagram to illustrate a process for the heat treatment of a film.

[0095] Fig. Figure 1 shows a heat treatment system 10 comprising a device 12 for heat treatment, for example drying, of a film 14, and the film 14 itself. The device 12 comprises a first radiant heating unit 16 and a first tempering roller 18. The first radiant heating unit 16 has in the Fig. Figure 1 shows three infrared emitters 20. The emitter unit 16 is designed to irradiate the foil 14 with electromagnetic radiation in order to heat it.

[0096] The emitter unit 16 is designed and arranged such that the film 14 is irradiated in the section of the film 14 that is in contact with the first temperature control roller 18. The infrared emitters 20 can be arranged such that they heat the film 14 uniformly. For example, the infrared emitters 20 are arranged at uniform intervals along the circumference of the first temperature control roller 18, over a distance along the circumferential direction that corresponds to the contact area of ​​the film 14 on the first temperature control roller 18.

[0097] The first temperature control roller 18 has a cylindrical body with a first lateral surface 18A. The first temperature control roller 18 is in the Fig. In the embodiment shown in Figure 1, the temperature control roller 18 is mounted to rotate freely. This means that the temperature control roller 18 is rotatable and can rotate, for example, due to the forward movement of the film 14. The film 14 has a first side and a second side. The first side of the film 14 rests against the first lateral surface 18A.

[0098] The first temperature control roller 18 deflects the foil 14 by an angle α of 90°. Thus, the foil 14 touches one quarter of the lateral surface 18A of the first temperature control roller 18.

[0099] The first emitter unit 16 is thus configured to homogeneously irradiate a quarter of the first surface area 18A in order to heat the film 14 uniformly along this section. Heating the film 14 dries it.

[0100] In the Fig. In the embodiment shown in Figure 1, the second side of the film 14 is irradiated. The film 14 can have a thickness of 100 µm to 1000 µm, so that the radiation incident on the second side of the film 14 from the emitter unit 16 heats the entire film 14.

[0101] As from Fig. As can be seen in Figure 4, the film 14 can have a substrate 14A, a first coating 14B, and / or a second coating 14C. The substrate 14A can be considered a support material that provides the mechanical stability of the film 14. Furthermore, the substrate 14A can serve as an electrical input or output conductor and / or can be made of metal, for example, aluminum or copper.

[0102] The first coating 14B and / or the second coating 14C can be considered the active material of the film 14. The first coating 14B and / or the second coating 14C can each have a thickness of 60 µm to 200 µm. The film 14 can be used, for example, in the manufacture of sodium-ion batteries or lithium-ion batteries.

[0103] The first coating 14B and / or the second coating 14C can be applied to the substrate 14A in the form of a so-called slurry. This slurry can have a water content of approximately 50% and is then dried to a water content of approximately 3%.

[0104] After this drying, the first coating 14B and / or the second coating 14C may have an excessively high water content, which can be reduced with the drying system 10 as part of the “post-drying”, i.e., that the film 14, in particular the first coating 14B and / or the second coating 14C, can be dried.

[0105] When the film 14 is irradiated by the first high-power emitter unit 16, there is a possibility that the film 14 will overheat, which can lead to damage to the film, especially to the first coating 14B and / or the second coating 14C. The first temperature control roller 18 is designed to cool and / or temper the film 14. This occurs along the surface where the film 14 contacts the first outer surface 18A. In other words, the film 14 is tempered by heat conduction of the heat present in the film 14 to the first temperature control roller 18. For this purpose, the first temperature control roller 18 can be made of a highly thermally conductive material, such as stainless steel or aluminum. In the Fig. In the embodiment shown in Figure 1, the first temperature control roller 18 is a solid component - i.e., a component without cavities, except for those for rotatably mounting the first temperature control roller 18.

[0106] The interplay of the film 14's movement speed, the radiant power of the first radiant unit 16, the thermal conductivity of the tempering roller 18, and / or the contact area of ​​the film 14 on the first surface 18A thus determines the temperature to which the film 14 is heated. Since the first radiant unit 16 only irradiates and thus heats that section of the film 14 which is in contact with the first surface 18A of the first tempering roller 18, the radiant power of the first radiant unit 16 can be increased (compared to a situation in which the first radiant unit 16 irradiates a section of the film 14 which is not in contact with the first tempering roller 18). This allows the film 14's movement speed to be increased, which in turn reduces the drying time.

[0107] The heat treatment system 10 according to the embodiment of Fig. 2 has the same optional features and / or embodiments as the heat treatment system 10 according to the embodiment of Fig. 1 except for the differences listed below.

[0108] The heat treatment system 10 according to the embodiment of Fig. 2 has a second temperature control roller 24 with a second outer surface 24A. The second temperature control roller 24 can be constructed identically to the first temperature control roller 18.

[0109] The first temperature control roller 18 and / or the second temperature control roller 24 can have a temperature control device 26 which has a cavity and a temperature control fluid (not shown in Fig. 2), and / or a liquid pump (not shown in Fig. 2) may include. The cavity of the temperature control device 26 is arranged adjacent to the first shell surface 18A and / or the second shell surface 24A. For example, the first shell surface 18A and / or the second shell surface 24A may form a wall of the cavity of the temperature control device 26.

[0110] The liquid pump can pump the temperature control fluid into the cavity to keep the first shell surface 18A and / or the second shell surface 24A at a constant temperature.

[0111] The first tempering roller 18 and / or the second tempering roller 24 each deflect the film 14 by 180°. The second tempering roller 24 is in contact with the second side of the film 14, and the second irradiating unit 22 irradiates the first side of the film 14. In this way, both sides of the film 14 can be dried.

[0112] The first emitter unit 16 and / or the second emitter unit 22 have in the embodiment according to Fig. 2 nine infrared emitters 20, each of which evenly irradiates one half of the first cladding surface 18A or the second cladding surface 24A.

[0113] The heat treatment system 10 according to the embodiment of Fig. 3 has the same optional features and / or embodiments as the heat treatment system 10 according to the embodiment of Fig. 2 except for the differences listed below.

[0114] The heat treatment system 10 further comprises a chamber 28, an unwind roller 30, a deflection roller 32, a rewind roller 34, a drive 36, a control unit 38, a pumping device 40 and / or a shield 42. The chamber 28 is airtight and can surround the first temperature control roller 18, the first radiant heating unit 16, the second temperature control roller 24, the second radiant heating unit 22, the unwind roller 30, the deflection roller 32, the rewind roller 34, the drive 36, and / or the shield 42. That is, the first temperature control roller 18, the first emitter unit 16, the second temperature control roller 24, the second emitter unit 22, the unwind roller 30, the deflection roller 32, the winding roller 34, the drive 36 and / or the shielding 42 are arranged inside the chamber 28.

[0115] The pump unit 40 is in gas communication with the chamber 28 and is configured to generate a negative pressure, optionally a vacuum, in the chamber 28. Alternatively or additionally to the pump unit 40, a drying unit (not shown in the figure) can be used. Fig. 3) is designed to lower the dew point of the gas present in chamber 28 to below 0 °C. The reduced pressure and / or the low dew point enhances the drying of the film 14 and can thus help to reduce the drying time.

[0116] Before the drying process begins, the unwinding roller 30 can be inserted into chamber 28. The film 14 is unwound from the unwinding roller 30 and deflected 180° by the first tempering roller 18. During this deflection, the film 14 is heated and thus dried by the first radiant heating unit 16. The film 14 is then deflected 180° by the second tempering roller 24 and fed to the deflecting roller 32. During this deflection, the film 14 is heated and thus dried by the second radiant heating unit 22. From the deflecting roller 32, the film 14 is fed to the winding roller 34 and wound onto it.

[0117] The movement of the foil 14 can be provided by the drive 36. The drive 36 can have one or more motors, for example electric motors, which drive one or more of the rollers 18, 22, 30, 32 or 34. In the Fig. In the embodiment shown in Figure 3, the unwind roller 30 and the rewind roller 34 are driven. The control of the unwind roller 30 and the rewind roller 34 is carried out by the control unit 38, which is in data communication with the unwind roller 30 and the rewind roller 34 in order to drive the unwind roller 30 and the rewind roller 34 synchronously.

[0118] The control unit 38 can also be in data communication with the first emitter unit 16, the second emitter unit 22 and / or the pump unit 40 in order to, for example, adjust the radiation power of the first emitter unit 16 and / or the second emitter unit 22 and / or the negative pressure in the chamber 28 by appropriately controlling the pump unit 40.

[0119] The shielding 42 can be a heat-reflecting cover that can ensure that the first emitter unit 16 and / or the second emitter unit 22 irradiate the foil 14 only in the areas where the foil 14 is in contact with the first cladding surface 18A and / or the second cladding surface 24A.

[0120] The heat treatment system 10 may further comprise a temperature sensor 44 configured to measure the temperature of the film 14 without contact. The temperature sensor 44 may include a pyrometer. Each device 12 may be assigned a temperature sensor 44. For example, each temperature sensor 44 may measure the temperature of the film 14 when the film 14 is in contact with the first tempering roller 18 or the second tempering roller 24.

[0121] The temperature sensor 44 can be in data communication with the controller 38, so that the controller 38 can control the drive 36 and / or the radiant power of the first radiator unit 16 and / or the second radiator unit 22 depending on the temperature measured by the temperature sensor 44.

[0122] A heat treatment process, optionally for drying, of slide 14 is shown in the block diagram of Fig. 5 described. In step S1, the unwinding roller 36 is inserted into the chamber 28 and a negative pressure, optionally a vacuum, is created in the chamber 28 by means of the pump device 40.

[0123] In step S2, the film 14 is deflected over the first tempering roller 18, and the deflected section of the film 14 is irradiated by the first radiant unit 16 to heat and thus dry it. Simultaneously, the deflected section of the film 14 is in contact with the first outer surface 18A to temper the film 14, for example, to protect it from overheating. The first side of the film 14 is in contact with the first outer surface 18A, and the second side of the film 14 is irradiated by the first radiant unit 16.

[0124] In step S3, the film 14 is deflected over the second tempering roller 24, and the deflected section of the film 14 is irradiated by the second radiant unit 22 to heat and thus dry it. Simultaneously, the deflected section of the film 14 is in contact with the second outer surface 24A to temper the film 14, for example, to protect it from overheating. The second side of the film 14 is in contact with the second outer surface 24A, while the first side of the film 14 is irradiated by the second radiant unit 22. Thus, the first radiant unit 16 and the second radiant unit 22 irradiate the film 14 from both sides, enabling drying of the film 14 from both sides.

[0125] In the subsequent step S4, the film 14 is guided over the deflection roller 32 to the winding roller 34 in order to be wound up by it. QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] DE 10 2011 108 421 B3

[0004]

Claims

[1] Device for heat treatment of a film (14) comprising a first emitter unit (16) configured to irradiate the foil (14) in order to heat the foil (14), and a first tempering roller (18) with a first lateral surface (18A) for contact with a first side of the film (14), wherein the first temperature control roller (18) is arranged to deflect the film (14) over the first lateral surface (18A), wherein the first cladding surface (18A) is configured to temper the foil (14), and wherein the first emitter unit (16) is arranged opposite the first cladding surface (18A) to irradiate a second side of the foil (14) along a section of the foil (14) that is in contact with the first cladding surface (18A). [2] Device according to claim 1, wherein the first temperature control roller (18) comprises metal, optionally stainless steel, copper and / or aluminium. [3] Device according to claim 1 or 2, wherein the first temperature control roller (18) has a temperature control device (26) for temperature control of the first outer surface (18A), wherein optionally the temperature control device (26) has a cavity that can be filled with a temperature control fluid. [4] Device according to one or more of the preceding claims, wherein the device (12) is configured to deflect the film (14) through the first tempering roller (18) by more than 90°, optionally more than 120°, further optionally by 180°. [5] Device according to one or more of the preceding claims, wherein the first temperature control roller (18) has a diameter greater than 50 cm. [6] Device according to one or more of the preceding claims, further comprising an airtight chamber (28), wherein the first emitter unit (16) and the first temperature control roller (18) are arranged in the chamber (28), where the device (12) further comprises a pumping device (40) configured to generate a negative pressure, optionally a vacuum, in the chamber (28), and / or the device (12) further comprises a drying device designed to maintain a gas in the chamber (28) at a dew point temperature below 0°C. [7] Device according to one or more of the preceding claims, further comprising a drive (36) and a control (38), wherein the drive (36) is configured to move the film (14) over the first tempering roller (18), and wherein the control unit (38) is in data communication with the first emitter unit (16) and the drive (36) in order to control the intensity of the radiation generated by the first emitter unit (16) and a speed of movement of the film (14), wherein optionally the device (12) further comprises a temperature sensor (44) for measuring a temperature of the film (14), wherein the temperature sensor (44) is in data communication with the control unit (38) and wherein the control unit (38) is further configured to regulate the intensity of the radiation generated by the first emitter unit (16) and / or a speed of movement of the film (14) depending on the temperature of the film (14). [8] Device according to one or more of the preceding claims, further comprising a second emitter unit (22) configured to irradiate the foil (14) in order to heat the foil (14), and a second temperature control roller (22) with a second outer surface (22A) for contact with the second side of the film (14), wherein the second temperature control roller (22) is arranged to deflect the film (14) over the second lateral surface (22A), wherein the second lateral surface (22A) is designed to temper the foil (14), and wherein the second emitter unit (22) is arranged opposite the second lateral surface (22A) in such a way as to irradiate a first side of the film (14) along a section of the film (14) which is in contact with the second lateral surface (22A). [9] Heat treatment system, comprising a device according to one or more of the preceding claims, and a film (14) comprising a substrate and a first coating, where the first coating is applied to the substrate on the second side. [10] Method for the heat treatment of a film (14) comprising the following steps, Deflection and simultaneous tempering of a first side of the film (14) by means of a first tempering roller (18), and Irradiation of a second side of the film (14) along a section of the film which is deflected by the first tempering roller (18) to heat the film (14).

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