COLD ROLLING DEVICE AND METHOD FOR CONTROLLED COLD ROLLING OF ALUMINUM FILM

Description

[0001] The invention relates to a cold rolling device for the controlled cold rolling of aluminum foil, in particular battery foil. The invention further relates to methods for the controlled cold rolling of aluminum foil, in particular battery foil.

[0002] A common method for producing thin aluminum strips and foils is cold rolling. In cold rolling, among other criteria, the flatness (i.e., the strip tension distribution under tension) and the evenness (i.e., the wave height in the untensioned state or with very low auxiliary tension) of the rolled foils are essential quality criteria for trouble-free further processing. To set and control a defined flatness or evenness, cold rolling mills typically have actuators to influence the roll gap or roll gap contour. These actuators are parameterized depending on the selected operating point (e.g., work roll or backup roll position) or depending on an inline measured strip tension distribution, optionally in a closed control loop. This can be achieved, for example, by roll bending, roll pivoting, or other means.This can be achieved by adjusting a contact force gradient across the roller width, by axially displacing the rollers, by using a contour-variable support roller, or by employing zone cooling. The respective actuators have specific operating ranges (linear, quadratic, biquadratic, xn< ) and physical limits within their adjustment or correction range.

[0003] Zone cooling is preferably used to control higher-order flatness defects. Zone cooling differs from other control mechanisms in that the temperature difference between the cooling medium and the work rolls, which serves as the driving force for the roll gap contour change, is generated by the forming process itself. The work rolls are temperature-controlled by the heat released during forming. Zone cooling reaches its limits when the amount of heat generated by the forming process is too small to establish an effective temperature difference between the work roll(s) and the cooling medium. Reducing the cooling medium temperature to increase the temperature difference is also limited, as factors such as the solubility of additives in the cooling medium or condensation on system components impose limitations.

[0004] A rolling mill with zone cooling (or alternatively zone heating) is known from US 8,166,785 B2. Furthermore, US 2017 / 0080467 A1 discloses a method for the thermal control of work rolls by local heating or cooling, but not for aluminum foil. In addition, WO 2013 / 175158 A1, which forms the basis for the preamble of claims 1, 8, and 10, describes an aluminum cold rolling mill with internal cooling and external zone heating.

[0005] Based on this, the present invention aims to meet high flatness requirements even for rolled products made from rolling operations with low heat input due to low forming work, namely in the cold rolling of aluminum foil.

[0006] According to a first aspect of the present disclosure, this problem is solved in a method according to claim 8 for the controlled cold rolling of aluminum foil, in particular battery foil, in which a cold rolling process is carried out on an aluminum foil using a cold rolling device having several rolls, in which the cold rolling process is controlled to check the flatness and / or the planarity of the aluminum foil, wherein the control is carried out at least partially via zone cooling on at least one of the several rolls, in particular on a work roll or on a backup roll, in the invention in that the at least one of the several rolls is heated over the entire roll width during the control via zone cooling, in particular by being supplied with a liquid heating medium or by being inductively heated.

[0007] The cold rolling process on the aluminum foil can be carried out in particular using a cold rolling device for the controlled cold rolling of aluminum foil, especially battery foil, wherein the cold rolling device has several rolls, wherein the cold rolling device has a control device which is configured to control a cold rolling process, in particular to check the flatness and / or the flatness of the aluminum foil, wherein the cold rolling device has a cooling medium supply device which is configured to supply at least one of the several rolls, in particular a work roll or a backup roll, with a liquid cooling medium, wherein the cold rolling device has a roll heating device which is configured to heat the at least one of the several rolls, wherein the cooling medium supply device is configured toTo supply several cooling zones of at least one of the several rollers with a liquid cooling medium in a separately controllable manner, wherein the control device is configured to carry out the control at least partially via zone cooling by controlling the cooling medium supply device, and wherein the roller heating device is configured to heat the at least one of the several rollers substantially across its entire width during the ongoing zone cooling. For this purpose, the control device can in particular be configured to control the roller heating device such that the at least one of the several rollers is heated substantially across its entire width during the ongoing zone cooling.

[0008] In particular, the roller heating device can be designed in the form of a heating medium application device which is configured to supply at least one of the several rollers with a liquid heating medium, wherein the control device can in particular be configured to control the heating medium application device in such a way that at least one of the several rollers is heated substantially over the entire roller width during the ongoing zone cooling by supplying at least one of the several rollers with a liquid heating medium substantially over the entire roller width during the ongoing zone cooling.

[0009] Alternatively, the roller heating device can be designed in the form of an inductive roller heating device, which is configured to inductively heat at least one of the several rollers, wherein the control device can in particular be configured to control the inductive roller heating device in such a way that at least one of the several rollers is inductively heated substantially over the entire roller width during the ongoing zone cooling.

[0010] In the previously described use of the cold rolling device or in the previously described method according to the first aspect of the present disclosure, by heating at least one of the several rolls over substantially the entire roll width, the roll is brought globally to an increased temperature level, which, even with low heat input due to the small pass reductions during the cold rolling process itself, ensures a sufficient temperature difference between the roll surface and the cooling medium, so that effective zone cooling is possible.

[0011] This means that during the cold rolling process, at least one of the several rolls is globally heated to a higher overall temperature level, combined with local cooling of the roll for zone cooling.

[0012] For this purpose, at least one of the several rolls is preferably heated substantially uniformly over substantially the entire width of the roll during the cold rolling process, in particular by being supplied with a liquid heating medium or heated inductively.

[0013] For example, it may be possible to heat the roll independently of the cold rolling process control, in particular by supplying it with the liquid heating medium or by heating it inductively. The heating of the roll, especially the supply of the heating medium or the inductive heating, is then not affected by the actual control system, but may, under certain circumstances, influence the control of other manipulated variables.

[0014] Furthermore, it may be possible to heat the roll with a base heating output, independent of the control of the cold rolling process, in particular by supplying it with a base flow rate of the liquid heating medium or by inductive heating. In addition to this base heating output, in particular this base flow rate, an additional heating output, in particular an additional flow rate of heating medium, can then be included as a control variable in the control system.

[0015] The basic throughput can be in the range of 30–300 l / h. The temperature of the liquid heating medium, especially oil, is preferably in the range of 65–85 °C. With these operating parameters, a sufficient temperature difference between the roller surface and the liquid cooling medium for zone cooling can be achieved, preferably in the range of 15–35 °C.

[0016] According to a second aspect of the present disclosure, the aforementioned problem is solved in a cold rolling device according to claim 1 for the controlled cold rolling of aluminum foil, in particular battery foil, wherein the cold rolling device has several rolls, wherein the cold rolling device has a control device which is configured to control a cold rolling process to check the flatness and / or the planarity of the aluminum foil, wherein the cold rolling device has a roll heating device which is configured to heat at least one of the several rolls, in particular a work roll or a backup roll, and wherein the roll heating device is configured to separately control several heating zones of the at least one of the several rolls, in the invention in that the control device is configured toThe control is to be carried out, at least partially, via inverse zone cooling by controlling the roll heating device, wherein the control device for the inverse zone cooling is configured to control the roll heating device in the event of a setpoint deviation of a controlled variable assigned to a first of the several heating zones, such that one or more second heating zones are heated more intensely relative to the first heating zone. The cold rolling device can be used, in particular, for the controlled cold rolling of aluminum foil, especially battery foil. Furthermore, the aforementioned objective according to the second aspect of the present disclosure is achieved in a method according to claim 10 for the controlled cold rolling of aluminum foil, especially battery foil, in which, using a cold rolling device having several rolls, in particular using a cold rolling device according to the second aspect of the present disclosure,A cold rolling process is carried out on an aluminum foil, in which the cold rolling process is controlled to monitor the flatness and / or the planarity of the aluminum foil, is solved according to the invention in that the control is carried out at least partially via inverse zone cooling on at least one of the several rolls, in particular on a work roll or on a backup roll, wherein in the case of inverse zone cooling, in the event of a setpoint deviation of a controlled variable that is assigned to a first of several heating zones of the at least one of the several rolls, one or more second heating zones are heated more strongly relative to the first heating zone.

[0017] In the cold rolling device described above and its use, or in the method described above according to the second aspect of the present disclosure, inverse zone cooling achieves a control that enables effective zone control even in the case of a pass with low forming work and thus low heat input.

[0018] While conventional zone cooling involves changing the local application of cooling medium to a cooling area of ​​a roller, inverse zone cooling instead involves changing the heating of complementary heating areas of the roller, specifically by changing the application of heating medium to complementary heating areas or by changing the inductive heating of complementary heating areas. Thus, instead of specifically cooling a local area of ​​the roller, inverse zone cooling selectively heats other, particularly adjacent, areas of the roller. In this way, an effective and corresponding influence between the different zones can be achieved. Therefore, inverse zone cooling involves heating, but not necessarily cooling.

[0019] Accordingly, the control device for inverse zone cooling is configured, in the event of a setpoint deviation of a controlled variable assigned to a first of several heating zones, to control the roller heating device in such a way that the heating of one or more second heating zones is increased relative to the first heating zone, and in particular, to control the heating medium supply device in such a way that the supply of heating medium to one or more second heating zones is increased relative to the first heating zone. Similarly, in the inverse zone cooling method, in the event of a setpoint deviation of a controlled variable assigned to a first of several heating zones of at least one of the several rollers, the heating of one or more second heating zones is increased relative to the first heating zone, and in particular, the supply of heating medium to one or more second heating zones is increased relative to the first heating zone.The one or more second heating zones are different heating zones than the first heating zone, preferably heating zones adjacent to the first heating zone.

[0020] The controlled variable assigned to a heating zone is, in particular, a controlled variable that relates to a position on the roll or on the cold-rolled aluminum foil corresponding to the position of the heating zone. For example, if the strip tension of the cold-rolled aluminum foil across its width (strip tension distribution) is recorded as the controlled variable, then a heating zone can be assigned the strip tension measured at the corresponding position across the width as its controlled variable.

[0021] By using complementary heating instead of local cooling (as in conventional zone cooling) in inverse zone cooling, flatness control or influence of the aluminum foil can be achieved even with low heat input in cold rolling operations with low forming heat.

[0022] The cold rolling device, its use and the method according to the first and second aspects each serve for the (flatness-)controlled cold rolling of aluminum foil, in particular battery foil.

[0023] Aluminum foil refers specifically to a strip-shaped material made of aluminum or an aluminum alloy with a maximum thickness of 200 µm. Aluminum strips, on the other hand, refer specifically to a similar strip-shaped material, but with a thickness greater than 200 µm.

[0024] In particular, the cold rolling devices described above can be used for cold rolling aluminum foil with a final thickness of 20 µm or less. Accordingly, the final thickness of the aluminum foil can be 20 µm or less with the described processes. At such final thicknesses, the heating of the roll(s) per pass is too low to achieve sufficient flatness control through conventional zone cooling. In contrast, the processes and cold rolling devices described here enable reliable flatness control even at such low final thicknesses.

[0025] The cold rolling process may involve, in particular, a texturing pass or skin pass. Such cold rolling processes typically result in low pass depths for thin foils and thus low forming work. Furthermore, the aluminum foil, in particular, may consist of a thermally unstable alloy, which therefore must be cold-rolled at reduced speed and / or with low pass depths to achieve certain strength values.

[0026] A thermally unstable alloy is defined as an alloy exhibiting a low recovery and / or recrystallization temperature. This leads to softening of the alloy's structure even at low temperatures.

[0027] The pass reduction per pass during the cold rolling process can be in the range of 1.5–55%. At these pass reductions, the heating of the roll(s) caused by the forming process when rolling aluminum foil is typically no longer sufficient on its own to achieve effective zone cooling, so that the use of the cold rolling device and the method according to the first and second aspects of this disclosure is particularly advantageous.

[0028] Preferably, aluminum foil intended for the production of battery electrodes, particularly battery cathodes, so-called battery foil, is cold-rolled. The use of the cold-rolling device and the process according to the first and second aspects are particularly advantageous for battery foil because, firstly, such foils are subject to particularly high customer flatness requirements. Secondly, battery foil often consists of non-thermostable alloys that recover at relatively low temperatures, so that low rolling temperatures are necessary to achieve the required high final strengths. These low temperatures are achieved in particular by small pass rates and / or low rolling speeds. At the same time, high flatness requirements are placed on battery foil, which cannot be met with higher-order flatness defects. Therefore, the use of the cold-rolling device and the process described here are particularly advantageous for battery foil.

[0029] With the described cold rolling device and the described methods according to the first and second aspects, especially when combining the first and second aspects, it is particularly possible to produce battery foils with a thickness in the range of 5 - 20 µm which have flatness deviations of < 2mm wave height at 8 N / mm 2< auxiliary tension over the strip width and strip length.

[0030] According to the first and second aspects, the cold rolling mill has several rolls. These rolls include, in particular, two work rolls. Work rolls are defined as those rolls that come into direct contact with the material being rolled. The roll gap, which has a widthwise contour, is located between the work rolls. In addition to the work rolls, the cold rolling mill may also have two or more backup rolls. A quarto cold rolling mill, for example, comprises two work rolls and two backup rolls. However, more than two backup rolls, such as intermediate rolls, may also be provided.

[0031] At least one of the several rollers can be either a working roller or a backup roller.

[0032] The control device of the cold rolling mill, as described in the first and second aspects, is designed to control the cold rolling process, in particular to monitor the flatness and / or planarity of the aluminum foil. The control system preferably also includes thickness control.

[0033] The control is preferably carried out in one or more, possibly coupled, control loops, in which one or more controlled variables are recorded and compared with associated reference variables, and depending on the comparison result, one or more manipulated variables are set.

[0034] According to the first aspect, the control system is designed to perform control, at least partially, via zone cooling by controlling the cooling medium supply unit. For this purpose, the cooling medium supply unit, or individual nozzles of the cooling medium supply unit, are controlled as manipulated variables within the control loop. Specifically, in zone cooling, the cooling medium supply unit, and in particular its individual nozzles, are controlled in such a way that the supply of cooling medium to the individual cooling zones of at least one of the several rollers is selectively varied.By selectively altering the supply of cooling medium to a cooling zone, in particular by changing the cooling medium flow rate and / or the cooling medium pressure and / or the cooling medium temperature for the cooling zone in question, the temperature of at least one of the several rolls in the cooling zone can be changed, resulting in a change in the thermal expansion of the roll in the cooling zone. In this way, the roll gap geometry can be locally influenced in the area of ​​the cooling zone, thus enabling higher-order roll gap correction.

[0035] According to the second aspect, the control device is configured to perform the control, at least partially, via inverse zone cooling by controlling the roller heating device, in particular the heating medium supply device. For this purpose, the roller heating device, especially the heating medium supply device or individual nozzles of the heating medium supply device, are controlled as manipulated variables of the control loop. In particular, during inverse zone cooling, the roller heating device, especially the heating medium supply device, and especially its individual nozzles, are controlled in such a way that the heating of one or more secondary heating zones of at least one of the several rollers is selectively changed, in particular the supply of heating medium to one or more secondary heating zones of at least one of the several rollers is selectively changed.By selectively altering the heating of one or more secondary heating zones, in particular by changing the supply of heating medium to these zones, specifically by modifying the heating medium flow rate, pressure, and / or temperature, the temperature of the roll in these zones can be changed. This results in a change in the roll's thermal expansion within these zones. In contrast, the roll exhibits no or only a minor change in thermal expansion in the one or more primary heating zones. This allows for local adjustment of the roll gap geometry within these zones, enabling higher-order roll gap correction.

[0036] The first and second aspects of the present disclosure can, in particular, also be combined. Accordingly, the regulatory mechanism can be designed, in particular, to a) to carry out the control at least partially via zone cooling by controlling the cooling medium supply device, wherein the roller heating device is controlled in such a way that at least one of the several rollers is heated during the ongoing zone cooling essentially over the entire roller width, in particular supplied with a liquid heating medium, and b) to carry out the control at least partially via inverse zone cooling by controlling the roller heating device.

[0037] The regulations concerning zone cooling and inverse zone cooling can be implemented simultaneously or sequentially, especially alternately.

[0038] In this way, the roll heating device adds enough energy to the rolling process to ensure that the zone cooling effect is functional even with low forming work. Additionally, by inverting the effect into targeted zone heating in reverse zone cooling, the roll gap contour can be directly influenced.

[0039] The heat input during zone cooling and / or reverse zone cooling can be controlled, particularly in a closed control loop, as a function of the inline measured strip tension distribution, optionally in combination with other flatness control elements. In this way, good results can be achieved for the flatness and evenness of the aluminum foil.

[0040] The following describes various embodiments of the cold rolling machine, its use, and the method according to the first aspect of this disclosure and the use and method according to the second aspect of this disclosure, wherein each embodiment applies independently to both the use of the cold rolling machine and the method according to the first aspect and to the cold rolling machine, its use, and the method according to the second aspect. Furthermore, the first and second aspects of this disclosure can be combined with one another. The individual embodiments can also be combined with one another as desired.

[0041] In one embodiment, the roller heating device is designed as a heating medium application unit configured to supply at least one of the several rollers with a liquid heating medium. Preferably, the heating medium application unit is configured to supply several heating zones of the at least one of the several rollers with a liquid heating medium in a separately controllable manner. The heating medium application unit can, in particular, have several nozzles arranged side by side in the direction of the roller axis, which are preferably controllable separately. Preferably, the flow rate, pressure, and / or the heating medium temperature of the individual nozzles can be adjusted. In this way, location-dependent application of the heating medium to the roller is enabled.According to the first aspect of the present disclosure, this heating medium application device also allows for a uniform, location-independent application of heating medium to the roller.

[0042] In a further embodiment, the roller heating device is designed as an inductive roller heating device, which is configured to inductively heat at least one of the several rollers, wherein the inductive roller heating device is particularly configured to separately control the inductive heating of the several heating zones of the at least one of the several rollers. In this way, location-dependent heating of the roller is made possible. According to the first aspect of the present disclosure, this inductive roller heating device can also be used to achieve uniform, location-independent heating of the roller.

[0043] In one embodiment, the cold rolling mill has a cooling medium application device configured to supply at least one of the several rolls with a liquid cooling medium. The cooling medium application device is preferably configured to supply several cooling zones of the at least one of the several rolls with a liquid cooling medium in a separately controllable manner. The cooling medium application device can, in particular, have several nozzles arranged side by side in the direction of the roll axis, which are preferably controllable separately. Preferably, the flow rate, pressure, and / or the cooling medium temperature of the individual nozzles can be adjusted. In this way, location-dependent application of the cooling medium to the roll is enabled. With this cooling medium application device, during use or...According to the second aspect of the present disclosure, the process also includes the application of cooling medium to the roller in addition to inverse zone cooling, in particular to supply the cold rolling process with sufficient rolling oil as a lubricant.

[0044] In one embodiment, the cold rolling device comprises a cooling medium application device and a heating medium application device, wherein the cooling medium application device comprises a first nozzle bar and the heating medium application device a second nozzle bar, the first and second nozzle bars each having a frame with adjacent, controllable nozzles. This allows for independent, and in particular simultaneous, application of the cooling medium and heating medium to the roll, thus enabling more flexible temperature control of the roll.

[0045] In another embodiment, the widths of the cooling zones and / or the heating zones of at least one of the several rollers are in the range of 10 - 150 mm.

[0046] In another embodiment, rolling oil is used as a heating and / or cooling medium. This eliminates the need for additional application of rolling oil. Preferably, at least one of the several rolls is continuously supplied with liquid cooling medium over essentially its entire width during the cold rolling process. Using rolling oil as the cooling medium ensures lubrication of the rolls. With continuous application of rolling oil to the roll, zone cooling can be achieved by locally varying the cooling medium flow rate, for example, by a predetermined average flow rate, or by varying the cooling medium temperature.

[0047] The cold rolling mill can include a detection device configured to measure the strip tension distribution of the cold-rolled aluminum foil, and the control device can be configured to perform control based on the values ​​measured by the detection device. A roller segmented transversely to the rolling direction, which has a certain degree of wrap around the aluminum foil, can be provided for measuring the strip tension distribution. By measuring the force on the individual segments of the roller, the respective strip tensions can be determined depending on their position transversely to the rolling direction, and thus the strip tension distribution can be determined. The measured values ​​from such a detection device represent suitable control variables for strip tension distribution control, thereby improving the flatness or evenness of the aluminum foil.The strip tension distribution control can be achieved in particular via zone cooling with simultaneous uniform application of heating medium to the roller and / or by inverse zone cooling.

[0048] In another embodiment, the liquid cooling medium has a cooling medium temperature in the range of 20–65 °C, preferably 35–45 °C. The minimum temperature of 20 °C, preferably 35 °C, ensures a stable solution state for the additives typically contained in the liquid cooling medium. The maximum temperature of 65 °C, preferably 45 °C, guarantees operation significantly below the flash point, thereby increasing operational reliability. Furthermore, potential oxidation by the cooling medium can be reduced.

[0049] In another embodiment, the cooling medium flow rate of the cooling medium supply unit is in the range of 200–5000 l / min, particularly 300–3000 l / min. Specifically, the cooling medium flow rate of the cooling medium supply unit can be in the range of 0.2 l / min to 1.0 l / min per mm of roll width. With a cooling medium flow rate below the aforementioned minimum flow rates, sufficient lubrication for the rolling process and adequate cleaning of the rolls by the cooling medium may not be guaranteed. With a cooling medium flow rate above the aforementioned maximum flow rates, excessive cooling of individual zones may occur, which can impair the rolling result.

[0050] In a further embodiment, the liquid heating medium has a heating medium temperature in the range of 60–100 °C, preferably 65–90 °C. Maintaining the aforementioned minimum heating medium temperature ensures a sufficient temperature difference between the roller and the cooling medium in the first aspect of the present disclosure, and a sufficient temperature difference between the roller and the heating medium in the second aspect of the present disclosure during reverse zone cooling. The maximum temperature of 100 °C, preferably 90 °C, also ensures operation below the flash point, thereby increasing operational reliability. Furthermore, potential oxidation by the cooling medium can be reduced.

[0051] In another embodiment, the heating medium flow rate of the heating medium application device is in the range of 0–500 l / min. In particular, the heating medium flow rate of the heating medium application device can be in the range of 0 l / min to 0.5 l / min per mm of roller width. Operation is no longer economical if the heating medium flow rate exceeds the aforementioned maximum flow rates.

[0052] In another embodiment, the cooling capacity of the cooling medium application device and / or the heating capacity of the heating medium application device is in the range of 50 - 200 kW per m of roller width.

[0053] Further advantages and features of the cold rolling device and the method will become apparent from the following description of exemplary embodiments, with reference to the attached drawing.

[0054] The drawing shows Fig. 1a - a cold rolling device for an embodiment of the use and method for the flatness-controlled cold rolling of aluminum foil according to the first and second aspects of the present disclosure, Fig. 2 - an illustration of the zone cooling known from the prior art, Fig. 3 - an embodiment of the use of the cold rolling device and the method according to the first aspect of the present disclosure, Fig. 4 - an embodiment of the cold rolling device, its use and the method according to the second aspect of the present disclosure, and Fig. 5 - an embodiment of the cold rolling device, its use and the method according to the first and second aspects of the present disclosure.

[0055] The Figuren 1a-b show an embodiment of a cold rolling device suitable for an embodiment of the use of the cold rolling device and the method for controlled cold rolling of aluminium foil according to the first and second aspects of the present disclosure. Fig. 1a shows a schematic sectional view according to the one in Fig. 1b section plane designated Ia. Fig. 1b shows a schematic view of the inlet side of the cold rolling mill according to the one in Fig. 1a The viewing plane designated Ib.

[0056] The cold rolling mill 2 has a cold rolling stand 4, which in this example is designed as a quarto cold rolling stand with an upper work roll 6, a lower work roll 8, an upper backup roll 12, and a lower backup roll 14. The roll gap 10 is located between the upper and lower work rolls 6 and 8. When rolling aluminum foil 20, a closed roll gap is typically used, since the work rolls 6 and 8 contact each other in the areas outside the aluminum foil 20 due to the thinness of the foil.

[0057] The cold rolling device 2 further comprises a control device 16, which is configured to perform (flatness) control of a cold rolling process in which the aluminum foil 20 fed to the cold rolling stand from the entry side 18 is cold rolled so that the aluminum foil 20 has a reduced thickness on the exit side 22. The control device 16 can, for example, comprise a microcontroller or control software installed on a computer.

[0058] The cold rolling device 2 can have a detection device 24 for determining the thickness of the aluminium foil 20 after rolling.

[0059] The cold rolling device 2 can further include a detection device 26 that measures the strip tension distribution of the cold-rolled aluminum foil 20. For this purpose, the detection device 26 can, for example, have several roller segments 27 arranged one behind the other transversely to the rolling direction, over which the aluminum foil 20 is guided. By measuring the force on the individual roller segments, the strip tension of the corresponding section of the aluminum foil 20 at the corresponding position transversely to the rolling direction can be measured, so that the strip tension distribution can be obtained from the measurements on different rollers.

[0060] To ensure sufficient wrapping of the aluminum foil 20 around the roller segments 27, additional rollers 36, 37 are preferably provided over which the aluminum foil 20 is guided. Roller 36 can be movable (see double arrow) to facilitate threading the aluminum foil 20 around the rollers 27, 36, 37.

[0061] The control device 16 is designed to control various components of the cold rolling machine 2 as manipulated variables, namely for example: a) Adjusting devices 30, 30' for adjusting the vertical position of the work rolls 6, 8 and / or the backup rolls 12, 14, b) Adjusting devices 32, 32' for adjusting a force gradient with which the work rolls 6, 8 press against each other across their width, c) Adjusting devices 33, 33' for bending the work rolls 6, 8 and / or the backup rolls 12, 14 and / or d) Adjusting devices 34, 35 for adjusting the strip tension on the entry or exit side, in particular an adjusting device for adjusting the uncoiling and / or winding speed.

[0062] Furthermore, the cold rolling device 2 has an upper and a lower cooling medium application device 38, 40, which are configured to supply the upper and lower work rolls 6, 8 with a liquid cooling medium, respectively. Alternatively or additionally, the cooling medium application devices 38, 40 can also be configured to supply a backup roll with a liquid cooling medium.

[0063] Furthermore, the cold rolling device 2 has roll heating devices 42, 44 in the form of an upper and a lower heating medium supply device, which are configured to supply the upper and lower work rolls 6, 8 with a liquid heating medium, respectively. Alternatively or additionally, the heating medium supply devices 38, 40 can also be configured to supply a backup roll with a liquid heating medium.

[0064] The cooling medium application devices 38, 40 and the heating medium application devices 42, 44 each comprise a frame 46, 47 with nozzles 48, 49 arranged side by side. The nozzles 48 of the cooling medium application devices 38, 40 are connected to a cooling medium supply 52 via supply lines 50, and the nozzles 49 of the heating medium application devices 42, 44 are connected to a heating medium supply 56 via supply lines 54. The cooling medium supply 52 can be configured, in particular, to supply rolling oil with an adjustable temperature in the range of 20–65 °C, especially 35–45 °C, as a cooling medium to the nozzles of the cooling medium application devices 38, 40. The heating medium supply 52 can in particular be configured to supply rolling oil with an adjustable temperature in the range of 60 - 100 °C, in particular 65 - 90 °C, as a heating medium to the nozzles of the heating medium application devices 42, 44.

[0065] Alternatively, it is also conceivable to connect the nozzles 48 of the cooling medium supply devices and the nozzles 49 of the heating medium supply devices to a common supply and to provide heating medium at the individual nozzles 49 of the heating medium supply devices 42, 44 to heat the rolling oil to the desired temperature range.

[0066] The nozzles 48 of the cooling medium supply units 38, 40 and the nozzles 49 of the heating medium supply unit can be individually controlled via the control unit 16, so that the quantity of rolling oil exiting each nozzle 48 or 49 can be selectively controlled. Each nozzle 48 of the cooling medium supply units 38, 40 is assigned to a respective cooling zone 58 of the associated work roll 6, 8, which can be supplied with cooling medium by this nozzle 48. Similarly, each nozzle 49 of the heating medium supply units 42, 44 is assigned to a respective heating zone 59 of the associated work roll 6, 8, which can be supplied with heating medium by this nozzle 49. The individual cooling and heating zones 58, 59 are described in Fig. 1b (as well as in the Fig. 2 - 4 ) are separated from each other by dashed lines. The cooling zones 58 and the heating zones 59 of a work roll can be - as in Fig. 1b The zones can be the same (each cooling zone corresponds to a respective heating zone) or different, whereby the cooling and heating zones may differ in particular in their respective number and / or width.

[0067] In an alternative embodiment, the roller heating devices 42, 44 can also be designed as inductive roller heating devices. Such a roller heating device comprises, for each heating zone 59 of a roller, in particular at least one respective associated induction coil, which can be individually controlled and supplied with a heating current in order to inductively heat the roller in the area of ​​the corresponding heating zone 59.

[0068] The control unit 16 is now configured to control, in particular the nozzles 48 of the cooling medium supply units 38, 40 and / or the nozzles 49 of the heating medium supply units 42, 44 as manipulated variables for the (flatness) control of a cold rolling process. In this way, the roll geometries of the work rolls 6 and 8 can be locally influenced, so that deviations of the controlled variables, especially from higher-order setpoints, can be corrected during the control process.

[0069] Possible control measures for the cold rolling process using the cooling medium supply devices 38, 40 and / or the heating medium supply devices 42, 44 are now described below based on the Figuren 2 - 4 explained.

[0070] The Fig. 2 - 4 The figures schematically show the upper work roll 6 of the cold rolling device with nozzles 48 of the cooling medium supply unit 38 and nozzles 48 of the heating medium supply unit 42. For clarity, the nozzles 48 of the cooling medium supply unit 38 are shown in the Fig. 2 - 4 For illustrative purposes, the nozzles 48 of the heating medium application device 38 are shown above and below the work roll 6 and are designated with reference numerals 48.1 to 48.11 and 49.1 to 49.11, respectively, to distinguish the individual nozzles. The corresponding cooling and heating zones of the work roll 6 are designated with reference numerals 58.1 to 58.11 and 59.1 to 59.11, respectively, with cooling zone 58.1 corresponding to nozzle 48.1, cooling zone 58.2 to nozzle 48.2, etc., heating zone 59.1 to nozzle 49.1, heating zone 59.2 to nozzle 49.2, etc.

[0071] Fig. 2 This first illustrates zone cooling, a method known from the prior art. In conventional zone cooling, individual nozzles are selectively controlled (in Fig. 2 e.g., nozzles 48.2 and 48.7) locally a larger throughput of cooling medium 60 on associated cooling zones of the work roll 6 (in Fig. 2 e.g. applied to the cooling zones 58.2 and 58.7), whereby the work roll 6 is locally cooled more strongly in the cooling zones concerned, so that the diameter of the work roll 6 changes locally in these cooling zones, in particular is reduced.

[0072] If, for example, during the control of the cold rolling process, it is determined that a property of a section of the cold-rolled aluminum foil 20 deviates from a guide parameter perpendicular to the rolling direction, in particular if it exhibits insufficient strip tension, then a local correction of the work roll diameter and thus the roll gap can be achieved by controlling the nozzle 48 of the cooling zone corresponding to this section, in particular by increasing the coolant flow rate of this nozzle. The change in the diameter of the work roll 6 is typically in the micrometer range with zone cooling.

[0073] However, when cold rolling aluminum foil 20 with small pass depths and / or slow rolling speeds, it has been shown that the surface of the work rolls 6, 8 does not heat up sufficiently due to the heat introduced during cold rolling to achieve a sufficient temperature difference to the temperature of the cooling medium for effective zone cooling. Furthermore, the temperature of the cooling medium cannot typically be reduced arbitrarily, as, for example, the solubility of additives in the cooling medium or condensation imposes limits. When cold rolling aluminum foil 20, the Fig. 2 The illustrated zone cooling based on the state of the art is therefore only of limited use.

[0074] Fig. 3 now illustrates an embodiment of the use of the cold rolling apparatus and the method according to the first aspect of the present disclosure with the in Fig. 1a-b cold rolling mill shown. For the in Fig. 3 In the illustrated regulation, the control device 16 is configured to control the heating medium supply device 42 in such a way that the work roll 6 is supplied with liquid heating medium 62 essentially over the entire roll width during the ongoing zone cooling by controlling the nozzles 49.1 - 49.11 of the heating medium supply device 42.

[0075] In this way, the surface temperature of the work roll 6 is increased across its entire width, ensuring a sufficient temperature difference to the liquid cooling medium 60 for effective zone cooling, even with small pass removals. In other words, the temperature level of the entire work roll 6 is increased by applying the heating medium 62 to the work roll 6.

[0076] Since local application of the heating medium to the work roll 6 is not required with this control system, the nozzles 49.1 - 49.11 of the heating medium application device 42 can also be controlled together, thus eliminating the need for individual nozzle control. Furthermore, instead of nozzles 49.1 - 49.11, a single longitudinal nozzle extending across the width of the work roll 6 can be provided, thereby enabling uniform application of the heating medium to the work roll 6.

[0077] In an alternative embodiment, the work roll 6 can be inductively heated over its entire width during the ongoing zone cooling process by controlling a provided inductive roll heating device. For this purpose, the inductive roll heating device can, for example, have at least one induction coil that extends over the entire width of the roll, thereby enabling uniform inductive heating of the work roll 6.

[0078] In Fig. 3 The actual zone cooling is achieved by the cooling medium application device 38 through local changes in the cooling medium flow rate of certain nozzles (in Fig. 3 (illustrated by arrows of different sizes). Preferably, all nozzles 48.1 - 48.11 of the cooling medium application device are operated with a predetermined basic flow rate, which is locally increased for zone cooling (in Fig. 3 (e.g., at nozzles 48.2 and 48.7). In this way, the nozzles of the cooling medium application unit 38 can simultaneously ensure the supply of rolling oil to the work roll 6 across the entire roll width, independent of the zone cooling, thus eliminating the need for a separate rolling oil supply. Alternatively, the supply of rolling oil for lubrication and cleaning can also be ensured by the heating medium application unit by operating nozzles 49.1–49.11 at a predetermined basic flow rate.

[0079] Fig. 4 now illustrates an embodiment of the cold rolling apparatus, its use and the method according to the second aspect of the present disclosure with the in Fig. 1a-b cold rolling mill shown. For the in Fig. 4 In the illustrated regulation, the control device 16 is set up to carry out the regulation at least partially via inverse zone cooling by controlling the heating medium supply device 42.

[0080] In inverse zone control, if there is a deviation in the setpoint of a controlled variable assigned to one or more first heating zones (in Fig. 4 e.g., heating zones 59.2 and 59.7), the heating medium supply device 42 is controlled in such a way that the supply of one or more second heating zones (in Fig. 4 e.g., the remaining heating zones 59.1, 59.3 - 59.6 and 59.8 - 59.11) are increased with heating medium. For this purpose, the heating medium flow rate of the nozzles assigned to these second heating zones (in Fig. 4 corresponding to nozzles 49.1, 49.3 - 49.6 and 49.8 - 49.11) increased (in Fig. 4 (e.g., from zero to a specific value).

[0081] For example, a control variable assigned to a heating zone could be the strip tension of the aluminum foil at the position corresponding to the heating zone, perpendicular to the rolling direction on the cold-rolled aluminum foil.

[0082] In (conventional) zone cooling, cooling takes place in the cooling areas affected by the setpoint deviation (see...). Fig. 2 In reverse zone cooling, areas other than the affected area are heated. In this way, local cooling is replaced by a complementary heating of the work roll 6, thereby achieving comparable local geometric adjustments of the work roll 6 and thus of the roll gap contour.

[0083] The use of a heating medium instead of a cooling medium ensures that even with small pass rates, there is a sufficient temperature difference to the work roll.

[0084] In the exemplary embodiment in Fig. 4 The work roll 6 continues to be supplied evenly with a basic flow rate of cooling medium via the cooling medium supply device 38 in order to provide sufficient rolling oil for the cold rolling process.

[0085] Fig. 5 schematically illustrates an embodiment of the cold rolling apparatus, its use and the method according to the first and second aspects of the present disclosure. Fig. 5 shows a control loop 70 with which the device 2 is controlled Fig. 1 It can be controlled by means of the regulation. Control loop 70 is in Fig. 5 For illustrative purposes, it is shown as a simple single-loop control system. However, the control system can also be designed as a multi-loop, especially a cascading, control system.

[0086] For the control loop, controlled variables 72 are recorded and compared with respective reference variables 76 in a reference unit 74. The comparison results are processed in the controller 78, which uses them to determine the manipulated variables 80. The control of the manipulated variables influences the controlled system 82, which itself is subject to external influences 84, and thus in turn influences the controlled variables 72, thereby closing the control loop.

[0087] In particular, one or more of the following control variables are suitable: nominal thickness of the cold-rolled aluminum foil 20; strip tensile stress distribution of the cold-rolled aluminum foil, other measured variables for the flatness and / or evenness of the cold-rolled aluminum foil 20; measured variables calculated from the aforementioned measured variables.

[0088] To detect the controlled variables, the device 2 has corresponding detection devices, in particular the detection device 26 for the strip tension distribution and, if necessary, further detection devices.

[0089] As guide parameters 76, corresponding specifications for the above-mentioned control variables are considered, in particular for the desired nominal thickness of the cold-rolled aluminum foil 20, for the desired flatness and / or evenness, for the desired strip tension distribution.

[0090] For the control in the controller 78, one or more of the following control options are particularly suitable, which can also be carried out simultaneously: thickness control, flatness control or planarity control.

[0091] The control variables 80 may include, in particular, one or more of the following: vertical distance between the work rolls 6, 8 (via the control devices 30, 30'), alignment of the work and / or backup rolls relative to each other or setting of a contact force gradient across the roll width (via the control devices 32, 32'), bending of the work and / or backup rolls (via the control devices 33, 33'), strip tension (via the control devices 34, 35), roll speed, supply of cooling or heating medium to the individual cooling and / or heating zones of the work rolls 6, 8 (via the cooling medium supply devices 38, 40 or the heating medium supply devices 42, 44).

[0092] The control loop 82 includes the cold rolling process, which is influenced on the one hand by the aforementioned control variables and on the other hand by external influences (e.g. ambient temperature fluctuations, fluctuations in thickness or mechanical properties of the supplied aluminum foil 20 etc.).

[0093] The reference variables can be stored in a memory of the control unit 16 in the device 2. Furthermore, the comparator unit 74 and the controller 78 can be implemented in the control unit 16. For example, the control unit 16 can have a memory with instructions whose execution on at least one microprocessor of the control unit 16 enables the implementation of the control according to Fig. 5 causes.

[0094] The controller 78 is configured to control the cooling medium supply devices 38, 40 and the heating medium supply devices 42, 44 in such a way that control via zone cooling with simultaneous supply of liquid heating medium to the entire roll width of the respective work roll is achieved (see Fig. 3 ) and / or that control is achieved via inverse zone cooling (see Fig. 4 ). At the same time, thickness control is preferably carried out so that the cold-rolled aluminum foil 20 has the desired nominal thickness and / or the desired thickness profile.

[0095] The thickness control can be carried out independently of the flatness control, for example on the basis of the aluminium foil thickness measured with the detection device 34 and by setting the global strip tension by controlling the uncoiling and / or coiling speed by means of the actuators 34 and / or 35.

Claims

1. Cold rolling apparatus (2) for controlled cold rolling of aluminum foil (20), in particular battery foil, - wherein the cold rolling apparatus (2) comprises a plurality of rolls (6, 8), - wherein the cold rolling apparatus (2) comprises a control device (16) which is configured to perform a control of a cold rolling operation for controlling the evenness and / or the flatness of the aluminum foil (20), - wherein the cold rolling apparatus (2) comprises a roll heating device (42, 44) configured to heat at least one of the plurality of rolls (6, 8), and - wherein the roll heating device (42, 44) is configured to separately controllably heat a plurality of heating zones (59.1 - 59.11) of the at least one of the plurality of rolls (6, 8), characterized - in that the control device (16) is configured to perform the control at least partly via inverse zone cooling by controlling the roll heating device (42, 44), wherein the control device (16) is configured, for the inverse zone cooling, to control, in the event of a setpoint deviation of a controlled variable assigned to a first of the plurality of heating zones (59.1 - 59.11), the roll heating device (42, 44) in such a way that one or more second heating zones (59.1 - 59.11) are heated more strongly relative to the first heating zone (59.1 - 59.11).

2. Cold rolling apparatus according to claim 1, characterized in that the roll heating device is designed in the form of a heating medium impingement device (42, 44) which is configured to impinge a liquid heating medium (62) on the at least one of the plurality of rolls (6, 8), the heating medium impingement device (42, 44) preferably being configured to separately controllably impinge a liquid heating medium (62) on a plurality of heating zones (59.1 - 59.11) of at least one of the plurality of rolls (6, 8).

3. Cold rolling apparatus according to claim 1, characterized in that the roll heating device is designed in the form of an inductive roll heating device, which is configured to inductively heat the at least one of the plurality of rolls (6, 8), the roll heating device preferably being configured to separately controllably inductively heat a plurality of heating zones (59.1 - 59.11) of the at least one of the plurality of rolls (6, 8).

4. Cold rolling apparatus according to one of claims 1 to 3, characterized in that the control device (16) is configured, for the inverse zone cooling, to control, in the event of a setpoint deviation of a controlled variable assigned to a first of the plurality of heating zones (59.1 - 59.11), the roll heating device (42, 44) in such a way that the impingement of heating medium (62) on one or more second heating zones (59.1 - 59.11) is increased relative to the first heating zone (59.1 - 59.11) or that the inductive heating power for one or more second heating zones (59.1 - 59.11) is increased relative to the first heating zone (59.1 - 59.11).

5. Cold rolling apparatus according to one of claims 1 to 4, characterized in that the cold rolling apparatus (2) has a cooling medium impingement device (38, 40) which is configured to impinge a liquid cooling medium (60) on the at least one of the plurality of rolls (6, 8), the cooling medium impingement device (38, 40) preferably being configured to separately controllably impinge a liquid cooling medium (60) on a plurality of cooling zones (58.1 - 58.11) of the at least one of the plurality of rolls (6, 8).

6. Cold rolling apparatus according to one of claims 2, 4 or 5, characterized in that the cooling medium impingement device (38, 40) comprises a first nozzle bar and the heating medium impingement device (42, 44) comprises a second nozzle bar, the first and second nozzle bars having a respective frame (46, 47) with nozzles (48.1 - 48.11; 49.1 - 49.11) being arranged side by side and each controllable.

7. Cold rolling apparatus according to any one of claims 1 to 6, characterized in that the cold-rolling apparatus (2) has a detection device (26) which is configured to measure measured values for a strip tension distribution of the cold-rolled aluminum foil (20), and in that the control device (16) is configured to perform the control as a function of the values measured by the detection device (26).

8. Method for the controlled cold rolling of aluminum foil (20), in particular battery foil, - in which a cold rolling operation is performed on an aluminum foil (20) using a cold rolling apparatus (2) having a plurality of rolls (6, 8), - in which a control of the cold rolling operation is performed for controlling the evenness and / or the flatness of the aluminum foil (20), characterized - in that the control is performed at least partly via a zone cooling on at least one of the plurality of rolls (6, 8) and - in that, during the control via the zone cooling, the at least one of the plurality of rolls (6, 8) is heated over the entire roll width, in particular is impinged by a liquid heating medium (62) or is inductively heated.

9. Method according to claim 8, characterized in that, during the cold rolling operation, the at least one of the plurality of rolls (6, 8) is heated substantially uniformly over substantially the entire roll width, in particular is impinged substantially uniformly over substantially the entire roll width by a liquid heating medium (62) or is inductively heated substantially uniformly over substantially the entire roll width.

10. Method for controlled cold rolling of aluminum foil (20), in particular battery foil, - in which a cold rolling operation is performed on an aluminum foil (20) using a cold rolling apparatus (2) having a plurality of rolls (6, 8), in particular using a cold rolling apparatus according to any one of claims 1 to 7, - in which a control of the cold rolling operation is performed for controlling the evenness and / or the flatness of the aluminum foil (20), characterized - in that the control is at least partly performed via inverse zone cooling on at least one of the plurality of rolls (6, 8), wherein, in the inverse zone cooling, in the event of a setpoint deviation of a controlled variable assigned to a first of a plurality of heating zones (59.1 - 59.11) of the at least one of the plurality of rolls (6, 8), one or more second heating zones (59.1 - 59.11) are heated more strongly relative to the first heating zone (59.1 - 59.11).

11. Method according to claim 10, characterized in that, in the inverse zone cooling, in the event of a setpoint deviation of a controlled variable assigned to a first of a plurality of heating zones (59.1 - 59.11) of the at least one of the plurality of rolls (6, 8), an impingement on one or more second heating zones (59.1 - 59.11) is increased relative to the first heating zone (59.1 - 59.11) or the inductive heating power for one or more second heating zones (59.1- 59.11) is increased relative to the first heating zone (59.1- 59.11).

12. Method according to any one of claims 8 to 11, characterized in that, during the cold rolling operation, liquid cooling medium (60) is continuously impinged on the at least one of the plurality of rolls (6, 8) over substantially the entire roll width.

13. Method according to any one of claims 8 to 12, characterized in that the control comprises a thickness control and / or a control of a strip tension distribution of the cold rolled aluminum foil (20).

14. Method according to any one of claims 8 to 13, characterized in that rolling oil is used as heating medium (62) and / or cooling medium (60).