Use of a cold rolling mill and method for controlled cold rolling of aluminum foil

Abstract

The present invention relates to the use of a cold rolling mill (2) for controlled cold rolling of an aluminum foil (20), particularly a battery foil, the cold rolling mill (2) including a plurality of rolls (6, 8), the cold rolling mill (2) including a control device (16) configured to implement control of the cold rolling operation, particularly to control the uniformity and / or flatness of the aluminum foil (20), the cold rolling mill (2) including cooling medium injection devices (38, 40) configured to inject a liquid cooling medium (60) onto at least one of the plurality of rolls (6, 8), and the cold rolling mill (2) including a cooling medium injection device (38, 40) configured to inject a liquid cooling medium (60) onto at least one of the plurality of rolls (6, 8). The cooling medium injection devices (38, 40) are configured to individually and controllably inject a liquid cooling medium (60) into a plurality of cooling zones (58.1 to 58.11) of at least one of the plurality of rolls (6, 8), and the control device (16) is configured to control at least in part by zone cooling by controlling the cooling medium injection devices (38, 40), and the control means (16) is configured to control the roll heating means (42, 44) such that at least one of the plurality of rolls (6, 8) is heated across substantially the entire roll width as the zone cooling proceeds. The present invention relates to yet another use of the cold rolling apparatus (2) and a method for controlled cold rolling of an aluminum foil (20).

Description

[Technical Field]

[0001] The present invention relates to the use of a cold rolling apparatus for the controlled cold rolling of aluminum foil, in particular battery foil. Furthermore, the present invention relates to a method for the controlled cold rolling of aluminum foil, in particular battery foil. [Background technology]

[0002] A common method for the production of thin aluminum strip and foil is cold rolling. In cold rolling, among other criteria, the flatness (i.e., strip tension distribution under strip tension) or uniformity (i.e., wave height in the untensioned state or at very low auxiliary tension), respectively, of the rolled foil are essential quality criteria for subsequent processing without rejects. To set and control a specific flatness or uniformity, respectively, cold rolling mills usually have actuators that influence, optionally in a closed control loop, the roll gap or roll gap contour, which is parameterized as a function of selected operating points (e.g., work roll bail, backup roll bail) or as a function of the strip tension distribution measured in the line, for example by roll bending, roll rotation or adjustment of the contact force gradient across the roll width, axial roll displacement, contour-variable backup roll, or by zone cooling, respectively. Each actuator has its own effective range (linear, quadratic, quartic, x ) within its operating or correcting range. n ) as well as physical limitations.

[0003] Zone cooling is preferably used to control higher order flatness errors. Zone cooling differs from other actuators in that the temperature difference between the work roll and the cooling medium used as the driving force for roll gap contour change is created from the forming operation itself. The temperature of the work roll is controlled by the amount of heat released during forming.

[0004] Zone cooling reaches its limit when the amount of heat generated from the forming operation is too low to establish an effective temperature differential of the work rolls relative to the cooling medium. Lowering the cooling medium temperature to increase the temperature differential also has a lower limit, as, for example, the solubility of additives in the cooling medium or condensate formation in plant components sets a limit.

[0005] A rolling mill with zone cooling (or alternatively zone heating) is known from US Pat. No. 5,623,999. Furthermore, US Pat. No. 5,623,999 discloses a method for thermal control of work rolls by localized heating or cooling, but not for aluminum foil.

[0006] Against this background, the present invention is based on the object of meeting high flatness requirements even in the case of rolled products from rolling passes which have a low heat input due to a low amount of forming, i.e. in the cold rolling of aluminum foil. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] U.S. Patent No. 8,166,785(B2) [Patent Document 2] U.S. Patent Application Publication No. 2017 / 0080467(A1) Summary of the Invention [Means for solving the problem]

[0008] According to a first aspect of the present disclosure, there is provided a use of a cold rolling mill for controlled cold rolling of aluminum foil, particularly battery foil, the cold rolling mill including a plurality of rolls, the cold rolling mill including a control device configured to implement control of the cold rolling operation, particularly to control the uniformity and / or flatness of the aluminum foil, the cold rolling mill including a cooling medium injection device configured to inject a liquid cooling medium onto at least one of the plurality of rolls, particularly a work roll or a backup roll, the cold rolling mill including a roll heating device configured to heat at least one of the plurality of rolls, the cooling medium injection device configured to individually and controllably inject the liquid cooling medium into a plurality of cooling zones of at least one of the plurality of rolls, and the control device configured to implement control at least in part by zone cooling by controlling the cooling medium injection device. This object is achieved by the present invention in that the roll heating device is configured to heat at least one of the plurality of rolls across substantially the entire roll width of the roll during zone cooling. To this end, the control device may be configured to control the roll heating device in particular in such a way that at least one of the rolls is heated over substantially the entire roll width during the zone cooling process.

[0009] In particular, the roll heating device may be in the form of a heating medium injection device configured to inject a liquid heating medium onto at least one of the plurality of rolls, and the control device may be configured to control the heating medium injection device in a manner such that at least one of the plurality of rolls is heated across substantially its entire roll width during zone cooling progression, in particular by injecting the liquid heating medium onto at least one of the plurality of rolls across substantially its entire roll width during zone cooling progression.

[0010] Alternatively, the roll heating device may be in the form of an induction roll heating device configured to inductively heat at least one of the plurality of rolls, and the controller may be configured, among other things, to control the induction roll heating device such that at least one of the plurality of rolls is inductively heated across substantially the entire roll width as the zone cooling proceeds.

[0011] According to a first aspect of the present disclosure, there is provided a method for controlled cold rolling of aluminum foil, particularly battery foil, in which a cold rolling operation is performed on an aluminum foil using a cold rolling mill having a plurality of rolls, particularly using the cold rolling mill described above, and in particular control of the cold rolling operation is performed to control the uniformity and / or flatness of the aluminum foil, and the control is performed at least in part by zone cooling of at least one of the plurality of rolls, particularly a work roll or a backup roll. The above-mentioned object is further achieved by the present invention in that at least one of the plurality of rolls is heated substantially across its entire roll width during the control by zone cooling, particularly by being injected with a liquid heating medium or being inductively heated.

[0012] In the above-described use of a cold rolling apparatus or in the above-described method according to the first aspect of the present disclosure, heating at least one of the rolls substantially over its entire roll width allows the roll to be brought to a high temperature across its entire area, even with low heat input resulting from small rolling pass reductions during the cold rolling operation itself, such that a sufficient temperature difference of the roll surface with respect to the cooling medium is achieved, thereby enabling effective zone cooling.

[0013] Thus, during cold rolling operations, in particular, global heating of at least one of several rolls to an overall higher temperature level is combined with local cooling of the rolls for zone cooling.

[0014] For this purpose, at least one of the rolls is preferably heated substantially uniformly throughout substantially the entire width of the roll during the cold rolling operation, in particular by being injected with a liquid heating medium or by being inductively heated.

[0015] For example, provision may be made for heating the rolls independently of the control of the cold rolling operation, particularly by injecting a liquid heating medium into them or by inductive heating. The heating of the rolls, particularly by injecting or inductive heating of the rolls with a heating medium, is not subject to actual control but may affect the control of other operating variables in certain circumstances.

[0016] Furthermore, provision may be made for heating the rolls independently of the control of the cold rolling operation with the basic heating power, in particular for injecting them with a basic flow rate of liquid heating medium, or for inductively heating them with the basic heating power. In addition to this basic heating power, in particular this basic flow rate, an additional heating power, in particular an additional flow rate of heating medium, can be included in the control as an operating variable.

[0017] The basic flow rate may in particular be in the range of 30 to 300 l / h. The temperature of the liquid heating medium, in particular the oil, is preferably in the range of 65 to 85° C. At these operating parameters, the temperature difference between the roll surface and the liquid cooling medium, which is sufficient to be able to realize zone cooling, is preferably in the range of 15 to 35° C.

[0018] According to a second aspect of the present disclosure, there is provided a use of a cold rolling mill for controlled cold rolling of aluminum foil, particularly battery foil, the cold rolling mill including a plurality of rolls, the cold rolling mill including a controller configured to implement control of the cold rolling operation, particularly to control the uniformity and / or flatness of the aluminum foil, the cold rolling mill having a roll heating device configured to heat at least one of the plurality of rolls, particularly a work roll or a backup roll, and the roll heating device configured to individually and controllably heat a plurality of heating zones of at least one of the plurality of rolls, wherein the above-mentioned object is realized by the present invention in that the controller is configured to implement the control at least in part by reverse zone cooling by controlling the roll heating device.

[0019] According to a second aspect of the present disclosure, in a method for controlled cold rolling of aluminum foil, particularly battery foil, a cold rolling operation is performed on an aluminum foil using a cold rolling mill having a plurality of rolls, particularly using the cold rolling mill according to the second aspect of the present disclosure, and the cold rolling operation is controlled, particularly to control the uniformity and / or flatness of the aluminum foil, the above-mentioned object is further achieved by the present invention in that the control is performed at least in part by reverse zone cooling of at least one of the plurality of rolls, particularly a work roll or a backup roll.

[0020] In the above use of a cold rolling mill or in the above method according to the second aspect of the present disclosure, reverse zone cooling provides control that allows effective zone control even in passes with low forming amounts and therefore low heat input.

[0021] While conventional zone cooling involves a change in the localized injection of a cooling medium into a cooling zone of a roll, reverse zone cooling instead involves a change in the heating of a complementary heated zone of a roll, particularly a change in the injection of a heating medium into a complementary heated zone of a roll or a change in the induction heating of a complementary heated zone of a roll. Thus, instead of specifically cooling a localized zone of a roll, reverse zone cooling involves targeted heating of other, particularly adjacent, zones of the roll. In this way, the effects of different zones that effectively correspond to each other can be achieved. Thus, reverse zone cooling involves heating but not necessarily cooling.

[0022] Thus, the control device is preferably configured for reverse zone cooling to control the roll heating devices in such a way that, in the event of a setpoint deviation of a control variable assigned to a first of the plurality of heating zones, the heating of one or more second heating zones is increased compared to the first heating zone, in particular to control the heating medium injection devices in such a way that the injection of heating medium into one or more second heating zones is increased compared to the first heating zone. Thus, preferably, in the method, in the event of a setpoint deviation of a control variable associated with a first of at least one of the plurality of heating zones of the plurality of rolls, the heating of one or more second heating zones is increased compared to the first heating zone, in particular the injection of heating medium into one or more second heating zones is increased compared to the first heating zone. The one or more second heating zones are heating zones different from the first heating zone, preferably heating zones adjacent to the first heating zone.

[0023] The control variables assigned to the heating zones are in particular control variables that refer to positions on the rolls or on the cold-rolled aluminum foil that correspond to the positions of the heating zones. For example, if the strip tensile stress of the cold-rolled aluminum foil is detected across its width as a control variable (strip tensile stress distribution), the heating zones can be assigned as control variables to the strip tensile stresses measured at corresponding positions across its width.

[0024] Because reverse zone cooling involves complementary heating instead of localized cooling (as in conventional zone cooling), it is possible to control or influence the flatness of aluminum foil during cold rolling operations even with low heat input for rolling passes with low heat of formation.

[0025] The uses and methods according to the first and second aspects in each case relate to the (flatness) controlled cold rolling of aluminium foil, in particular battery foil.

[0026] Aluminum foil is understood to mean, in particular, a strip-shaped material made of aluminum or an aluminum alloy and having a thickness of less than or equal to 200 μm, whereas aluminum strip is understood to mean, in particular, the corresponding strip-shaped material, but having a thickness of more than 200 μm.

[0027] In particular, the cold rolling mill described above can be used to cold roll aluminum foils having a final thickness of 20 μm or less. Thus, the final thickness of the aluminum foil in the described method may be, in particular, 20 μm or less. At such a final thickness, the roll heating per pass is too low to provide sufficient flatness control by conventional zone cooling. In contrast, the method and cold rolling mill described herein can achieve reliable flatness control even at such low final thicknesses.

[0028] The cold rolling operation may be, in particular, a texturing pass or a skin-pass rolling pass. Such cold rolling operations typically have low rolling pass reductions at low foil thicknesses, and thus low forming amounts. Furthermore, aluminum foils may be made of alloys that have low thermal stability and therefore must be cold rolled at reduced speeds and / or low pass reductions to achieve specific strength values.

[0029] Thermally unstable alloys are alloys that have low recovery and / or recrystallization temperatures, which leads to softening of such alloys even at low temperatures.

[0030] The pass reduction per pass in the present cold rolling operation may in particular be in the range of 1.5 to 55%. At these pass reductions, the heating of the rolls caused by the forming operation when rolling the aluminum foil is typically not sufficient to enable effective zone cooling alone, making the uses and methods according to the first or second aspects of the present disclosure particularly advantageous.

[0031] Preferably, aluminum foil intended for the production of battery electrodes, particularly battery positive electrodes, so-called battery foils, is cold-rolled. On the one hand, the uses and methods according to the first and second aspects are particularly advantageous for battery foils, since customers of such foils have particularly high uniformity requirements. On the other hand, battery foils often consist of thermally unstable alloys that recover at relatively low temperatures, and therefore require low rolling temperatures to achieve the required high final strength, which is achieved, in particular, by low pass reductions and / or low rolling speeds. At the same time, high-order flatness defects impose high uniformity requirements on battery foils that cannot be met. Therefore, the uses and methods described herein are particularly advantageous for battery foils.

[0032] The uses and methods according to the first and second aspects described, particularly when the first and second aspects are combined, can provide a strip width and strip length of 8 N / mm 2 It is possible to produce battery foils with thicknesses in the range of 5-20 μm, with a uniform deviation of wave height of <2 mm at an auxiliary tension of 100 μm.

[0033] According to the first and second aspects, the cold rolling mill includes a plurality of rolls. In particular, the plurality of rolls includes two work rolls. Work rolls are understood to mean rolls that are in direct contact with the rolled material. A roll gap is arranged between the work rolls, and the roll gap has a roll gap contour in the width direction. In addition to the work rolls, the cold rolling mill can have two or more backup rolls. For example, a quarto cold rolling mill includes two work rolls and two backup rolls. However, three or more backup rolls, for example, an intermediate roll, may also be provided.

[0034] At least one of the rolls may be a work roll or a backup roll, respectively.

[0035] The control device for the cold rolling apparatus according to the first and second aspects is configured to perform control of the cold rolling operation, particularly to control the uniformity and / or flatness of the aluminum foil. Preferably, the control also includes thickness control.

[0036] Control is preferably performed in one or more, possibly coupled, control loops in which one or more controlled variables are sensed and compared with associated reference variables, and one or more manipulated variables are set in response to the comparison.

[0037] According to a first aspect, the control device is configured to control at least partly by zone cooling by controlling the cooling medium injection device. For this purpose, in particular, the cooling medium injection device or its individual nozzles are controlled as manipulated variables in the control loop. In particular, during zone cooling, the cooling medium injection device, in particular its individual nozzles, is controlled in such a way that the injection of cooling medium into at least one individual cooling zone of the plurality of rolls is varied in a targeted manner. By selectively varying the injection of cooling medium into the cooling zones, in particular by varying the cooling medium flow rate and / or cooling medium pressure and / or cooling medium temperature for each cooling zone, the temperature of at least one of the plurality of rolls can be varied in each cooling zone, so that a thermal expansion change of the roll occurs within each cooling zone. In this way, the roll gap geometry can be locally influenced in the region of each cooling zone, enabling higher-order roll gap modifications.

[0038] According to a second aspect, the control device is configured to control at least part of the reverse zone cooling by controlling the roll heating device, particularly the heating medium injection device. For this purpose, the roll heating device, particularly the heating medium injection device or the individual nozzles of the heating medium injection device, are controlled as manipulated variables in a control loop. In particular, during reverse zone cooling, the roll heating device, particularly the heating medium injection device, particularly the individual nozzles thereof, is controlled in such a way that the heating of one or more second heating zones of at least one of the rolls is specifically varied, particularly the injection of the heating medium into one or more second heating zones of at least one of the rolls. By selectively varying the heating of one or more second heating zones, particularly the injection of the heating medium into one or more second heating zones, particularly by varying the heating medium flow rate and / or heating medium pressure and / or heating medium temperature for each second heating zone, the temperature of the roll in each second heating zone can be varied to change the thermal expansion of the roll in each second heating zone. In contrast, in one or more first heating zones, the rolls exhibit no or at least smaller thermal expansion changes, which allows for localized influence of the roll gap geometry in the region of the relevant first heating zone, enabling higher order roll gap modifications.

[0039] The first and second aspects of the present disclosure may in particular be combined with each other. a) controlling the cooling medium injection device, and the roll heating device is controlled in such a way that at least one of the rolls is heated during the zone cooling process, in particular by injecting the liquid heating medium over substantially the entire roll width, thereby implementing the control at least partially using zone cooling; and b) controlling the roll heating device so as to effect control at least in part by reverse zone cooling; It may be configured.

[0040] The control by zone cooling and the control by reverse zone cooling can be carried out simultaneously or successively, in particular alternately.

[0041] In this method, on the one hand, sufficient energy is added to the rolling operation by the roll heater so that the zone cooling effect is again functional even with low forming amounts, and, furthermore, this effect can be reversed to targeted zonal heating in reverse zone cooling, thereby directly influencing the roll gap contour.

[0042] The heat input during zone cooling and / or reverse zone cooling may be controlled in a closed control loop, in particular as a function of the strip tension distribution measured in the line, optionally superimposed with other flatness actuators. In this way, good results can be achieved with regard to the flatness and uniformity of the aluminum foil.

[0043] Various embodiments of the uses and methods according to the first aspect of the present disclosure and the second aspect of the present disclosure are described below, with each embodiment independently applying to both the uses and methods according to the first aspect and the second aspect. Furthermore, the first and second aspects of the present disclosure may be combined. Furthermore, the individual embodiments may be combined with each other as desired.

[0044] In one embodiment, the roll heating device is designed in the form of a heating medium injection device configured to inject a liquid heating medium onto at least one of the rolls, preferably configured to individually controllably inject the liquid heating medium into multiple heating zones of at least one of the rolls. The heating medium injection device may have multiple nozzles, particularly those arranged next to each other in the direction of the roll axis and preferably individually controlled. Preferably, the flow rate, pressure, and / or heating medium temperature of each nozzle can be adjusted. In this way, it is possible to apply the heating medium to the roll in a position-dependent manner. According to the first aspect of the present disclosure, the heating medium injection device can also be used for uniform, position-independent injection of the heating medium onto the roll.

[0045] In a further embodiment, the roll heating device is designed in the form of an induction roll heating device configured to inductively heat at least one of the rolls, in particular an induction roll heating device configured to individually and controllably inductively heat a plurality of heating zones of at least one of the rolls. In this way, position-dependent heating of the roll is possible. According to the first aspect of the present disclosure, this induction roll heating device can also be used to provide uniform, position-independent heating of the roll.

[0046] In an embodiment, the cold rolling mill includes a cooling medium injection device configured to inject a liquid cooling medium onto at least one of a plurality of rolls, preferably configured to individually controllably inject the liquid cooling medium into a plurality of cooling zones of at least one of the plurality of rolls. The cooling medium injection device may have a plurality of nozzles, preferably individually controlled, arranged adjacent to one another in the direction of the roll axis. Preferably, the flow rate, pressure, and / or cooling medium temperature of each nozzle can be adjusted. In this manner, position-dependent injection of the cooling medium onto the roll is possible. With this cooling medium injection device, in the use or method according to the second aspect of the present disclosure, the roll may be injected with a cooling medium in addition to reverse zone cooling, particularly to provide sufficient rolling oil as a lubricant for the cold rolling operation.

[0047] In one embodiment, the cold rolling mill includes a cooling medium injection device and a heating medium injection device, the cooling medium injection device including a first nozzle bar and the heating medium injection device including a second nozzle bar, the first nozzle bar and the second nozzle bar having respective frames with adjacently arranged, controllable nozzles. In this way, independent, particularly simultaneous, injection of cooling medium and heating medium into the rolls is possible, thus enabling more flexible temperature control of the rolls.

[0048] In a further embodiment, the width of the cooling and / or heating zone of at least one of the rolls is in the range of 10 to 150 mm.

[0049] In a further embodiment, rolling oil is used as the heating medium and / or cooling medium. In this method, additional injection of rolling oil is not required. Preferably, during the cold rolling operation, a liquid cooling medium is continuously injected onto at least one of the rolls substantially across the entire roll width. If rolling oil is used as the cooling medium, lubrication of the roll can be ensured in this method. When rolling oil is continuously injected onto the roll, zone cooling can be achieved, for example, by varying the cooling medium flow rate around a predetermined average cooling medium flow rate or by locally changing the cooling medium temperature.

[0050] The cold rolling mill may have a detection device configured to measure the strip tensile stress distribution of the cold-rolled aluminum foil, and the control device may be configured to implement control as a function of the value measured by the detection device. To measure the strip tensile stress distribution, a segmented roll may be provided that is segmented in a direction transverse to the rolling direction, and the aluminum foil is wound around the segmented roll to some extent. By measuring the force at each segment of the roll, it is possible to determine the respective strip tensile stress as a function of each position in the direction transverse to the rolling direction, and thus the strip tensile stress distribution. The measurements of such a detection device represent suitable control variables for strip tension distribution control, which can improve the flatness or uniformity of the aluminum foil. In particular, strip tension distribution control can be achieved by zone cooling with simultaneous uniform application of a heating medium to the roll and / or by reverse zone cooling.

[0051] In a further embodiment, the liquid coolant has a coolant temperature in the range of 20 to 65°C, preferably 35 to 45°C. On the one hand, a minimum temperature of 20°C, preferably 35°C, ensures a stable solution state of additives typically contained in the liquid coolant. On the other hand, a maximum temperature of 65°C, preferably 45°C, ensures operation well below the flash point, which increases operational safety. Furthermore, possible oxidation by the coolant can be reduced.

[0052] In a further embodiment, the coolant flow rate of the coolant injection device is in the range of 200 to 5000 l / min, in particular 300 to 3000 l / min. In particular, the coolant flow rate of the coolant injection device may be in the range of 0.2 to 1.0 l / min per mm of roll width. At coolant flow rates below the minimum rates mentioned above, sufficient lubrication for the rolling operation and sufficient cleaning of the rolls by the coolant may not be guaranteed. At coolant flow rates above the maximum rates mentioned, excessive cooling of individual zones may occur, which may worsen the rolling result.

[0053] In another embodiment, the liquid heating medium has a heating medium temperature in the range of 60 to 100°C, preferably 65 to 90°C. Maintaining this minimum heating medium temperature ensures a sufficient temperature difference between the roll and the cooling medium in the first aspect of the present disclosure, and ensures a sufficient temperature difference between the roll and the heating medium in the reverse zone cooling of the second aspect of the present disclosure. A maximum temperature of 100°C, preferably 90°C, ensures operation below the flash point, thereby increasing operational safety. Furthermore, it reduces potential oxidation by the cooling medium.

[0054] In a further embodiment, the heating medium flow rate of the heating medium injection device is in the range of 0 to 500 l / min. In particular, the heating medium flow rate of the heating medium injection device may be in the range of 0 to 0.5 l / min per mm of roll width. At heating medium flow rates above the stated maximum flow rates, operation is no longer economical.

[0055] In a further embodiment, the cooling capacity of the cooling medium injection device and / or the heating capacity of the heating medium injection device is in the range of 50 to 200 kW per m of roll width.

[0056] Further advantages and features of the cold rolling apparatus and method will become apparent from the following description of the embodiments, which refers to the accompanying drawings. [Brief explanation of the drawings]

[0057] [Figure 1A] 1 shows a cold rolling apparatus for an exemplary embodiment of the use and method of cold rolling controlled flatness aluminum foil according to the first and second aspects of the present disclosure; [Figure 1B] 1 shows a cold rolling apparatus for an exemplary embodiment of the use and method of cold rolling controlled flatness aluminum foil according to the first and second aspects of the present disclosure; [Figure 2] 1 shows an example of zone cooling known from the prior art. [Figure 3] 1 illustrates an exemplary embodiment of a use and method according to a first aspect of the present disclosure. [Figure 4] 10 illustrates an exemplary embodiment of a use and method according to the second aspect of the present disclosure. [Figure 5] 1 illustrates embodiments of uses and methods according to the first and second aspects of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0058] 1A and 1B show a cold rolling apparatus suitable for an exemplary embodiment of the use and method of controlled cold rolling of aluminum foil according to the first and second aspects of the present disclosure. Fig. 1A shows a schematic cross-sectional view corresponding to the cross-section designated Ia in Fig. 1B. Fig. 1B shows a schematic view of the feed side of the cold rolling apparatus corresponding to the cross-section designated Ib in Fig. 1A.

[0059] The cold rolling mill 2 has a cold rolling stand 4, which in this example is designed as a quarter cold rolling stand having an upper work roll 6, a lower work roll 8, an upper backup roll 12, and a lower backup roll 14. A roll gap 10 is disposed between the upper and lower work rolls 6, 8. When rolling the aluminum foil 20, the work rolls 6, 8 contact each other in areas outside the aluminum foil 20 due to the thin thickness of the aluminum foil 20, so the roll gap is typically called a closed gap.

[0060] The cold rolling mill 2 further includes a controller 16 configured to perform (flatness) control of the cold rolling operation, in which the aluminum foil 20 fed to the cold rolling mill from a feed side 18 is cold rolled so that the aluminum foil 20 has a reduced thickness at a discharge side 22. The controller 16 may include, for example, a microcontroller control system or control software installed on a computer.

[0061] The cold rolling mill 2 may be equipped with a detection device 24 for determining the thickness of the aluminum foil 20 after rolling.

[0062] The cold rolling apparatus 2 may further include a detection device 26 for measuring the strip tension distribution of the cold-rolled aluminum foil 20. For this purpose, the detection device 26 may have, for example, a plurality of roll segments 27 arranged one after the other in a direction transverse to the rolling direction, through which the aluminum foil 20 is guided. By measuring the force at each roll segment, it is possible to measure the strip tensile stress of the relevant section of the aluminum foil 20 at a corresponding position in the direction transverse to the rolling direction, resulting in the strip tensile stress distribution being obtained from measurements at different rolls.

[0063] To achieve sufficient wrapping of the aluminum foil 20 around the roll segment 27, additional rolls 36, 37 are preferably provided along which the aluminum foil 20 is guided. The roll 36 may be movable (see double-headed arrow) to facilitate threading of the aluminum foil 20 around the rolls 27, 36, 37.

[0064] The control device 16 controls the various components of the cold rolling mill 2, i.e., a) adjusting actuators 30, 30' for adjusting the vertical position of the work rolls 6, 8 and / or backup rolls 12, 14; b) adjustment actuators 32, 32' for adjusting the gradient of the force of the work rolls 6, 8 pressing against each other in the width direction; c) adjusting actuators 33, 33' for bending the work rolls 6, 8 and / or the backup rolls 12, 14 and / or d) Adjustment actuators 34, 35 for adjusting the strip tension on the feed or discharge side, in particular for adjusting the unwinding and / or rewinding speed. is configured to control as a manipulated variable.

[0065] Additionally, the cold rolling mill 2 includes upper and lower coolant injectors 38, 40 configured to inject a liquid coolant onto the upper and lower work rolls 6, 8, respectively. Alternatively or additionally, the coolant injectors 38, 40 may be configured to inject a liquid coolant onto the backup rolls.

[0066] Additionally, the cold rolling mill 2 includes roll heating devices 42, 44 in the form of upper and lower heating medium injectors configured to inject a liquid heating medium onto the upper and lower work rolls 6, 8, respectively. Alternatively or additionally, the heating medium injectors 38, 40 may be configured to inject a liquid heating medium onto the backup rolls.

[0067] The cooling medium injection devices 38, 40 and the heating medium injection devices 42, 44 each include a frame 46, 47 having nozzles 48, 49 arranged side by side. The nozzles 48 of the cooling medium injection devices 38, 40 are connected to a cooling medium supply source 52 via a supply line 50, and the nozzles 49 of the heating medium injection devices 42, 44 are connected to a heating medium supply source 56 via a supply line 54. The cooling medium supply source 52 may be configured to supply rolling oil having an adjustable temperature in the range of 20 to 65°C, particularly 35 to 45°C, as the cooling medium to the nozzles of the cooling medium injection devices 38, 40. The heating medium supply source 52 may be configured to supply rolling oil having an adjustable temperature in the range of 60 to 100°C, particularly 65 to 90°C, as the heating medium to the nozzles of the heating medium injection devices 42, 44.

[0068] Alternatively, it is also conceivable to connect the nozzles 48 of the cooling medium injection devices and the nozzles 49 of the heating medium injection devices to a common supply source and to provide heating means at the individual nozzles 49 of the heating medium injection devices 42, 44 in order to heat the rolling oil to the desired temperature range.

[0069] The nozzles 48 of the cooling medium injection devices 38, 40 and the nozzles 49 of the heating medium injection devices can be individually controlled by the control device 16, thereby selectively controlling the amount of rolling oil sprayed from each nozzle 48 or nozzle 49. Each nozzle 48 of the cooling medium injection devices 38, 40 is assigned to a respective cooling zone 58 of the corresponding work rolls 6, 8, and can inject a cooling medium into the cooling zone through this nozzle 48. Correspondingly, each nozzle 49 of the heating medium injection devices 42, 44 is assigned to a respective heating zone 59 of the corresponding work rolls 6, 8, and can inject a heating medium into the heating zone through this nozzle 49. The individual cooling zones 58 or heating zones 59 are separated from one another in FIG. 1B (as in FIGS. 2 to 4) by dashed lines. The cooling zones 58 and heating zones 59 of the work roll may be the same (each cooling zone corresponds to a respective heating zone), as shown in FIG. 1B, or may be different; if different, the cooling zones and heating zones may differ, particularly in their respective number and / or their respective widths.

[0070] In an alternative embodiment, the roll heating devices 42, 44 may also be designed as induction roll heating devices, which in particular comprise at least one respective induction coil associated with each heating zone 59 of the roll through which a heating current can flow in an individually controllable manner for inductively heating the roll in the region of the corresponding heating zone 59.

[0071] The control device 16 is then configured to control the nozzles 48 of the cooling medium injectors 38, 40 and / or the nozzles 49 of the heating medium injectors 42, 44 as manipulated variables for (flatness) control of the cold rolling operation. In this way, the roll geometry of the work rolls 6, 8 can be locally influenced, in particular so that deviations of the controlled variables from higher-order setpoint variables can be corrected during control.

[0072] Possible control of the cold rolling operation using cooling medium injectors 38, 40 and / or heating medium injectors 42, 44 will now be described below with reference to Figures 2-4.

[0073] 2-4 schematically illustrate the upper work roll 6 of the cold rolling mill along with the nozzles 48 of the cooling medium injection device 38 and the nozzles 48 of the heating medium injection device 42. For illustrative purposes, in FIGS. 2-4, the nozzles 48 of the cooling medium injection device 38 are depicted above the work roll 6 and the nozzles 48 of the heating medium injection device 38 are depicted below, with reference numerals 48.1-48.11 and 49.1-49.11, respectively, provided to identify the individual nozzles. Associated cooling and heating zones of the work roll 6 are correspondingly provided with reference numerals 58.1-58.11 and 59.1-59.11, respectively, with cooling zone 58.1 assigned to nozzle 48.1, cooling zone 58.2 assigned to nozzle 48.2, etc., heating zone 59.1 assigned to nozzle 49.1, heating zone 59.2 assigned to nozzle 49.2, etc.

[0074] Figure 2 first illustrates zone cooling as known from the prior art. In conventional zone cooling, by selective control of individual nozzles (e.g., nozzles 48.2 and 48.7 in Figure 2), a greater flow rate of cooling medium 60 is locally applied to associated cooling zones of work roll 6 (e.g., cooling zones 58.2 and 58.7 in Figure 2), as a result of which work roll 6 is locally cooled more intensely in the associated cooling zones, and so the diameter of work roll 6 is locally changed, in particular reduced, in these cooling zones.

[0075] During the control of a cold rolling operation, if it is determined that the properties of a section of the cold-rolled aluminum foil 20 in a direction perpendicular to the rolling direction deviate from the reference variable, in particular that the strip tensile stress is too low, a local correction of the work roll diameter, and thus the roll gap, can be achieved by controlling the nozzles 48 of the cooling zone corresponding to this section, in particular by increasing the coolant flow rate of this nozzle. The change in diameter of the work roll 6 during zone cooling is typically in the μm range.

[0076] However, when cold rolling aluminum foil 20 with small pass reductions and / or slow rolling speeds, it has been found that the surfaces of the work rolls 6, 8 do not become hot enough due to the heat introduced during cold rolling to achieve a sufficient temperature difference from the cooling medium temperature for effective zone cooling. Furthermore, the temperature of the cooling medium typically cannot be arbitrarily reduced because, for example, the solubility of additives in the cooling medium or condensate formation sets a limit. Therefore, in cold rolling aluminum foil 20, prior art zone cooling, as illustrated in FIG. 2, can only be used to a limited extent.

[0077] Next, Figure 3 illustrates an example embodiment of a use and method according to the first aspect of the present disclosure using the cold rolling apparatus shown in Figures 1A and 1B. In the control illustrated in Figure 3, the control device 16 is configured to control the heating medium injection device 42 in such a way that the liquid heating medium 62 is injected onto the work roll 6 substantially across the entire roll width by controlling the nozzles 49.1 to 49.11 of the heating medium injection device 42 during zone cooling progression.

[0078] In this way, the surface temperature of the work roll 6 is increased overall across the roll width, thereby ensuring a sufficient temperature difference with the liquid cooling medium 60 and therefore effective zone cooling even in the case of actual zone cooling with small pass reductions. In other words, the temperature of the entire work roll 6 is increased by applying the heating medium 62 to the work roll 6.

[0079] The nozzles 49.1 to 49.11 of the heating medium injection device 42 can also be controlled together, thus eliminating the need for individual control of the nozzles, since this control does not require a localized application of the heating medium to the work roll 6. Furthermore, instead of the nozzles 49.1 to 49.11, only a single longitudinal nozzle can be provided, which extends across the width of the work roll 6 and thus allows the heating medium to be injected uniformly onto the work roll 6.

[0080] In an alternative embodiment, the work roll 6 may be inductively heated across substantially the entire roll width during zone cooling by controlling the provided induction roll heating device. To this end, the induction roll heating device may include, for example, at least one induction coil extending across substantially the entire roll width, thereby enabling uniform induction heating of the work roll 6.

[0081] In FIG. 3, the actual zone cooling by the coolant injection device 38 is performed by local variations in the coolant flow rate of specific nozzles (illustrated in FIG. 3 by arrows of different sizes). Preferably, all nozzles 48.1 to 48.11 of the coolant injection device are operated at a predetermined base flow rate, and the base flow rate is increased locally (e.g., at nozzles 48.2 and 48.7 in FIG. 3) for zone cooling. In this way, the nozzles of the coolant injection device 38 ensure the simultaneous supply of rolling oil to the work roll 6 across the entire roll width, independent of zone cooling, so that a separate supply of rolling oil is unnecessary. Alternatively, the heating medium injection device can be used to ensure the supply of rolling oil for lubrication and cleaning by operating nozzles 49.1 to 49.11 at a predetermined base flow rate.

[0082] Next, Figure 4 illustrates an exemplary embodiment of the use and method according to the second aspect of the present disclosure using the cold rolling mill illustrated in Figures 1A and 1B. In the control illustrated in Figure 4, the controller 16 is configured to perform the control at least in part by reverse zone cooling by controlling the heating medium injector 42.

[0083] In the reverse zone control, in the event of a setpoint deviation of a control variable assigned to one or more first heating zones (e.g., heating zones 59.2 and 59.7 in FIG. 4), the heating medium injection device 42 is controlled in such a way that the injection of heating medium into one or more second heating zones (e.g., the remaining heating zones 59.1, 59.3 to 59.6 and 59.8 to 59.11 in FIG. 4) is increased. For this purpose, the heating medium flow rate of the nozzles assigned to these second heating zones (correspondingly, nozzles 49.1, 49.3 to 49.6 and 49.8 to 49.11 in FIG. 4) is increased (e.g., from zero to a specified value in FIG. 4).

[0084] The control variable assigned to a heating zone may be, for example, the strip tension of the aluminum foil at a position in the cold-rolled aluminum foil that corresponds to the heating zone in a direction perpendicular to the rolling direction.

[0085] Thus, while (traditional) zone cooling involves cooling the cooling zone affected by the set point shift (see FIG. 2), reverse zone cooling involves heating zones that are different from the affected zones. In this way, localized cooling is replaced by complementary heating of the work roll 6, thereby achieving the same degree of localized geometric adjustment of the work roll 6, and thus the roll gap contour.

[0086] The use of a heating medium instead of a cooling medium ensures that there is a sufficient temperature difference with the work rolls even during small rolling pass reductions.

[0087] In the exemplary embodiment of FIG. 4, a base flow rate of cooling medium is more uniformly injected onto the work rolls 6 by the cooling medium injector 38 to provide sufficient rolling oil for the cold rolling operation.

[0088] Figure 5 schematically illustrates an exemplary embodiment of the uses and methods according to the first and second aspects of the present disclosure. Figure 5 illustrates a control loop 70 that can be used to control the device 2 of Figure 1 using closed-loop control. For illustrative purposes, the control loop 70 is illustrated in Figure 5 as a simple single-loop control loop. Alternatively, the control loop can be designed as a multi-loop, particularly a cascaded control loop.

[0089] A controlled variable 72 is obtained for the control loop and is compared to a respective reference variable 76 in a comparison unit 74. The comparison result is processed in a controller 78, which uses the comparison result to determine a manipulated variable 80. Control of the manipulated variable affects a controlled system 82, which is itself subject to external influences 84 and thus in turn to the controlled variable 72, thereby closing the control loop.

[0090] In particular, one or more of the following controlled variables may be considered as controlled variables: the nominal thickness of the cold rolled aluminum foil 20, the strip tension distribution of the cold rolled aluminum foil, other measured variables related to the flatness and / or uniformity of the cold rolled aluminum foil 20, and measurement variables calculated from the aforementioned measurement variables.

[0091] For detecting the control variables, the device 2 has corresponding detection devices, in particular a detection device 26 for the strip tension distribution and, if necessary, further detection devices.

[0092] As reference variables 76, the settings of corresponding set points for the above-mentioned control variables can be considered, in particular for the desired nominal thickness of the cold-rolled aluminum foil 20, for the desired flatness and / or uniformity, for the desired strip tension distribution.

[0093] For control in the controller 78, in particular one or more of the following controls, which may be carried out simultaneously, may be considered: thickness control, uniformity control or flatness control.

[0094] One or more of the following operating variables can be considered as operating variables 80: the vertical distance of the work rolls 6, 8 from each other (by adjusting actuators 30, 30'), the alignment of the work rolls and / or backup rolls relative to each other or adjustment of the contact force gradient across the roll width (by adjusting actuators 32, 32'), the bending of the work rolls and / or backup rolls (by adjusting actuators 33, 33'), the strip tension (by adjusting actuators 34, 35), the rolling speed, the injection of cooling or heating media into the individual cooling and / or heating zones of the work rolls 6, 8 (by cooling media injectors 38, 40 or heating media injectors 42, 44).

[0095] In this specification, the controlled system 82 comprises a cold rolling operation, which is influenced on the one hand by the above-mentioned operating variables and on the other hand by external influences (e.g., ambient temperature fluctuations, variations in the thickness or mechanical properties of the supplied aluminum foil 20, etc.).

[0096] In the device 2, the reference variable may in particular be stored in a memory of the control device 16. Furthermore, the comparison unit 74 and the controller 78 may be implemented in the control device 16. For example, the control device 16 may have a memory with instructions, the execution of which in at least one microprocessor of the control device 16 causes the control according to Figure 5 to be performed.

[0097] Herein, the controller 78 is configured to control the cooling medium injectors 38, 40 and the heating medium injectors 42, 44 in such a manner that control is achieved by zone cooling using simultaneous injection of a liquid heating medium across the entire roll width of each work roll (see FIG. 3) and / or by reverse zone cooling (see FIG. 4). At the same time, thickness control is preferably achieved such that the cold-rolled aluminum foil 20 has a desired nominal thickness and / or a desired thickness profile.

[0098] The thickness control can be performed independently of the uniformity or flatness control, for example, based on the aluminum foil thickness measured by the sensing device 34 and by setting the global strip tension by controlling the unwinding and / or rewinding speed using the actuators 34 and / or 35, respectively.

Claims

1. A cold rolling apparatus (2) for controlled cold rolling of an aluminum foil (20), comprising: - said cold rolling mill (2) comprises a plurality of rolls (6, 8); - said cold rolling device (2) comprises a control device (16) configured to effect control of the cold rolling operation to control the uniformity and / or flatness of said aluminium foil (20); - the cold rolling mill (2) comprises a roll heating device (42, 44) configured to heat at least one of the rolls (6, 8); and the roll heating devices (42, 44) are configured to individually and controllably heat the heating zones (59.1 to 59.11) of at least one of the rolls (6, 8); In the cold rolling device (2), the control device (16) is configured to control the roll heating devices (42, 44) and thereby perform the controlling at least partly by reverse zone cooling, and the control device (16) is configured for the reverse zone cooling to control the roll heating devices (42, 44) in such a way that, when a control variable for controlling the uniformity and / or flatness of the aluminum foil (20) assigned to a first heating zone of the plurality of heating zones (59.1 to 59.11) deviates from a reference variable set as a corresponding set point for a desired uniformity and / or flatness, instead of changing the cooling or heating to the first heating zone affected by the deviation, one or more second heating zones of the plurality of heating zones (59.1 to 59.11) are heated more intensively compared to the first heating zones (59.1 to 59.11); A cold rolling apparatus (2) characterized by:

2. the roll heating device is designed in the form of a heating medium injection device (42, 44) configured to inject a liquid heating medium (62) onto the at least one of the rolls (6, 8), and the heating medium injection device (42, 44) is configured to individually and controllably inject the liquid heating medium (62) into the plurality of heating zones (59.1 to 59.11) of the at least one of the rolls (6, 8).

2. The cold rolling apparatus of claim 1.

3. the roll heating device is designed in the form of an induction roll heating device configured for induction heating of at least one of the rolls (6, 8), and the roll heating device is configured for individually controllable induction heating of the heating zones (59.1 to 59.11) of at least one of the rolls (6, 8).

2. The cold rolling apparatus of claim 1.

4. the control device (16) is configured to control the roll heating devices (42, 44) for the reverse zone cooling in such a way that, when a control variable for controlling the uniformity and / or flatness of the aluminum foil (20) assigned to a first heating zone of the plurality of heating zones (59.1 to 59.11) deviates from a reference variable set as a corresponding set point for a desired uniformity and / or flatness, the injection of the heating medium (62) into the one or more second heating zones of the plurality of heating zones (59.1 to 59.11) is increased compared to the first heating zones (59.1 to 59.11) or the induction heating power for the one or more second heating zones of the plurality of heating zones (59.1 to 59.11) is increased compared to the first heating zones (59.1 to 59.11). The cold rolling apparatus according to any one of claims 1 to 3.

5. the cold rolling apparatus (2) has a cooling medium injection device (38, 40) configured to inject a liquid cooling medium (60) onto the at least one of the plurality of rolls (6, 8), and the cooling medium injection device (38, 40) is configured to individually and controllably inject the liquid cooling medium (60) into a plurality of cooling zones (58.1 to 58.11) of the at least one of the plurality of rolls (6, 8).

5. A cold rolling mill according to claim 1, 3 or 4.

6. the cold rolling apparatus (2) has a cooling medium injection device (38, 40) configured to inject a liquid cooling medium (60) onto the at least one of the plurality of rolls (6, 8), and the cooling medium injection device (38, 40) is configured to individually and controllably inject the liquid cooling medium (60) into a plurality of cooling zones (58.1 to 58.11) of the at least one of the plurality of rolls (6, 8).

3. The cold rolling apparatus according to claim 2.

7. the cooling medium injection devices (38, 40) comprise a first nozzle bar, and the heating medium injection devices (42, 44) comprise a second nozzle bar, the first and second nozzle bars having respective frames (46, 47) with nozzles (48.1 to 48.11; 49.1 to 49.11) arranged side by side and each of which is controllable; 7. The cold rolling apparatus of claim 6.

8. the cold rolling apparatus (2) has a detection device (26) configured to measure a measurement value for strip tension distribution of the cold rolled aluminum foil (20), and the control device (16) is configured to perform the control as a function of the value measured by the detection device (26). The cold rolling apparatus according to any one of claims 1 to 7.

9. A method for controlled cold rolling of aluminum foil (20), comprising: - a cold rolling operation is carried out on the aluminum foil (20) using a cold rolling device (2) having a plurality of rolls (6, 8), - Control of the cold rolling operation is carried out to control the uniformity and / or flatness of the aluminium foil (20), said control being at least partly carried out by zone cooling in at least one of the rolls (6, 8); In the method, - when controlled by said zone cooling, said at least one of said rolls (6, 8) is heated over its entire roll width; A method characterized by:

10. During the zone cooling control, at least one of the rolls (6, 8) is heated across the entire roll width by being sprayed with a liquid heating medium (62) or by being inductively heated.

10. The method of claim 9.

11. during the cold rolling operation, said at least one of said plurality of rolls (6, 8) is heated substantially uniformly across substantially the entire roll width; 11. The method according to claim 9 or 10.

12. During the cold rolling operation, the at least one of the plurality of rolls (6, 8) is heated substantially uniformly across substantially the entire roll width by being sprayed with a liquid heating medium (62) substantially uniformly across substantially the entire roll width or by being inductively heated substantially uniformly across substantially the entire roll width. The method of claim 11.

13. A method for controlled cold rolling of aluminum foil (20), comprising: - a cold rolling operation is carried out on the aluminum foil (20) using a cold rolling device (2) having a plurality of rolls (6, 8), - Control of the cold rolling operation is carried out to control the uniformity and / or flatness of the aluminium foil (20), In the method, the control is at least partly performed by reverse zone cooling in at least one of the rolls (6, 8), in which, when a control variable for controlling the uniformity and / or flatness of the aluminum foil (20) assigned to a first heating zone of the at least one plurality of heating zones (59.1-59.11) of the rolls (6, 8) deviates from a reference variable established as a corresponding set point for the desired uniformity and / or flatness, one or more second heating zones of the plurality of heating zones (59.1-59.11) are heated more intensely than the first heating zone (59.1-59.11) instead of changing the cooling or heating to the first heating zone affected by the deviation, A method characterized by:

14. In the reverse zone cooling, if a control variable for controlling the uniformity and / or flatness of the aluminum foil (20) assigned to the first heating zone of the at least one of the plurality of heating zones (59.1-59.11) of the plurality of rolls (6, 8) deviates from a reference variable set as a corresponding set point for a desired uniformity and / or flatness, the injection to the one or more second heating zones of the plurality of heating zones (59.1-59.11) is increased compared to the first heating zone (59.1-59.11) or the induction heating power for the one or more second heating zones of the plurality of heating zones (59.1-59.11) is increased compared to the first heating zone (59.1-59.11). The method of claim 13.

15. During the cold rolling operation, a liquid cooling medium (60) is continuously sprayed onto at least one of the rolls (6, 8) over substantially the entire roll width. The method according to any one of claims 9 to 14.

16. The control includes controlling the thickness of the cold-rolled aluminum foil (20) and / or controlling the strip tension distribution. The method according to any one of claims 9 to 15.

17. A rolling mill oil is used as the heating medium (62) and / or the cooling medium (60). The method according to any one of claims 9 to 16.

18. Use of a cold rolling device (2) according to any one of claims 1 to 8 for the controlled cold rolling of an aluminium foil (20).

19. The method according to any one of claims 9 to 17, wherein the aluminium foil (20) is a battery foil.

20. 19. Use according to claim 18, wherein the aluminium foil (20) is a battery foil.

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