Work roller for a rolling mill for laminating sheets of alkali metals or their alloys into a film

Abstract

A work roller for a rolling mill for laminating sheets of an alkali metal or an alloy thereof into a film is disclosed. The work roller comprises a cylindrical core defining a central axis, wherein the core has an outer surface forming a lamination surface; and first and second truncated conical portions extending from first and second ends of the core, respectively. When the central axis is straight, the angle between the outer surface of the core and the outer surface of each of the first and second truncated conical portions is less than 0.05 degrees. The width of the core is greater than the width of each of the first and second truncated conical portions. The width of the core is less than the sum of the widths of the first and second portions. A rolling mill having two such work rollers is also disclosed.

Description

Technology Field

[0001] Cross-reference

[0002] This application claims the benefit of U.S. Provisional Application No. 62 / 936,806, filed November 18, 2019, U.S. Provisional Application No. 62 / 936,809, filed November 18, 2019, and U.S. Provisional Application No. 62 / 936,814, filed November 18, 2019, the entire disclosures of which are incorporated herein by reference.

[0003] Technology field

[0004] The technology of the present invention relates to a work roller for a rolling mill for laminating sheets of alkali metal or its alloy into a film, and a rolling mill having such a work roller. Background Technology

[0005] Rechargeable batteries manufactured from a laminate of a solid polymer electrolyte and thin-film anodes and cathodes exhibit several advantages compared to conventional liquid electrolyte batteries. These advantages include lower overall battery weight, higher specific energy, longer service life, and environmental friendliness as the risk of toxic liquid leakage into the environment is eliminated.

[0006] Solid polymer battery components include an anode, a cathode, and an insulating material capable of allowing ion conductivity, such as a solid polymer electrolyte sandwiched between the electrodes. The anode or cathode is typically manufactured from lightweight metal films, such as alkali metals and their alloys, including lithium metal and lithium-aluminum alloys. The composite cathode or anode is typically formed from a mixture of active materials, such as transition metal oxides, an electrically conductive filler, typically carbon particles, an ion-conducting polymer electrolyte material, and a current collector, typically a thin aluminum sheet. The composite cathode thin film is generally obtained by coating it onto the current collector.

[0007] The fabrication of lithium thin films with a thickness of less than 100 microns and a length of hundreds of meters, for example in the form of wide bands of more than 10 centimeters, by a rapid and reliable process faces significant technical difficulties due to the extreme physical and chemical properties of this metal, such as chemical reactivity, malleability, low mechanical strength, rapid self-welding by simple contact, and strong adhesion on most solid materials.

[0008] Cold extrusion is used for the continuous production of sheets of 100 microns or more. These thicknesses are generally suitable for the manufacture of lithium batteries using liquid electrolytes. For lower thicknesses, the film obtained by extrusion is then laminated between work rollers made of hard material.

[0009] In large-scale manufacturing processes, there are numerous difficulties in achieving efficient stacking of dense lithium at various thicknesses ranging from 20 to 100 microns for the manufacture of polymer electrolyte batteries.

[0010] Laminated lithium metal often reacts with and / or deforms against the working rollers it contacts during the lamination process, causing it to adhere. This problem can be solved by the use of lubricants as described in U.S. Patents No. 5,837,401, No. 5,528,920, and No. 6,019,801, the full contents of which are incorporated herein by reference. The lubricant contains additives that prevent the thin laminated lithium film from reacting with or excessively adhering to the working rollers and do not affect the electrochemistry of the resulting electrochemical cell. However, there is a need for the proper and efficient application of the lubricant during the lamination process.

[0011] The extreme ductility of lithium or its alloys allows only very small drawing tension to the lithium film exiting the work roller. Therefore, drawing tension must be precisely monitored and controlled to prevent breakage or tearing of the lithium film and consequently costly manufacturing shutdowns.

[0012] It is difficult to laminate a film of lithium or its alloy with a thickness of 20 to 100 microns with a uniform thickness across the entire width of the film and along the extended length of the film. Thickness variations occur across the width of the lithium film laminated in conventional lamination processes, which promotes breakage of the lithium film during the lamination operation and makes the resulting laminated lithium film less suitable for electrochemical cells.

[0013] Working rollers are traditionally manufactured from polyacetal, a rigid plastic material that is lithium-compatible (i.e., does not react with lithium). However, in large-scale manufacturing, polyacetal rollers wear out rapidly, requiring frequent replacement and disposal of worn rollers, which significantly increases costs. This makes the additive manufacturing process economically difficult.

[0014] Therefore, there is a need for a rolling mill suitable for laminating sheets of alkali metals or their alloys into a film that solves at least some of the aforementioned problems. There is also a need for an alkali metal film produced by such a rolling mill that maintains desirable properties across the width and length of the film. The problem to be solved

[0015] The objective of the technology of the present invention is to improve at least some of the inconveniences existing in the prior art. means of solving the problem

[0016] According to one aspect of the technology of the present invention, a rolling mill is provided for laminating a sheet of an alkali metal or an alloy thereof into a film. The rolling mill comprises: a frame; a first working roller rotatably mounted on the frame; a second working roller rotatably mounted on the frame, wherein the first and second working rollers are positioned to receive a sheet between them; at least two first actuators operably connected to opposite ends of the first working roller to bend the first working roller; and at least two second actuators operably connected to opposite ends of the second working roller to bend the second working roller. Each of the first and second working rollers has a cylindrical core defining a central axis, wherein the core has an outer surface forming a lamination surface; a first truncated conical portion extending from a first end of the core; and a second truncated conical portion extending from a second end of the core. When the central axis is a straight line, the angle between the outer surface of the center and the outer surface of each of the first and second truncated cone parts is less than 0.05 degrees. The width of the center is greater than the width of each of the first and second truncated cone parts. The width of the center is smaller than the sum of the widths of the first and second parts.

[0017] In some embodiments of the technology of the present invention, the angle is less than 0.03 degrees.

[0018] In some embodiments of the technology of the present invention, the angle is less than 0.02 degrees.

[0019] In some embodiments of the technology of the present invention, the angle is greater than 0.01 degrees.

[0020] In some embodiments of the technology of the present invention, for each of the first and second working rollers, the center, the first truncated cone portion and the second truncated cone portion have a chrome coating.

[0021] In some embodiments of the technology of the present invention, the chrome coating is a hard chrome coating.

[0022] In some embodiments of the technology of the present invention, for each of the first and second work rollers, the center, the first truncated conical portion and the second truncated conical portion have a surface roughness in the range of 0.025 micron Ra to 0.5 micron Ra.

[0023] In some embodiments of the technology of the present invention, the range is 0.05 micron Ra to 0.3 micron Ra.

[0024] In some embodiments of the technology of the present invention, for each of the first and second work rollers, the first and second truncated conical portions are tapered as they extend away from the center.

[0025] In some embodiments of the technology of the present invention, for each of the first and second working rollers: a first shoulder is formed between the center and the first truncated conical portion; and a second shoulder is formed between the center and the second truncated conical portion.

[0026] In some embodiments of the technology of the present invention, for each of the first and second work rollers: the first truncated conical portion is tapered as the first truncated conical portion extends from its outer end toward the center; and the second truncated conical portion is tapered as the second truncated conical portion extends from its outer end toward the center.

[0027] In some embodiments of the technology of the present invention, a first backup roller is rotatably mounted on a frame. The first backup roller contacts the first work roller to apply pressure on the first work roller. A second backup roller is rotatably mounted on a frame, and the second backup roller contacts the second work roller to apply pressure on the second work roller.

[0028] According to another aspect of the technology of the present invention, a work roller for a rolling mill for laminating sheets of an alkali metal or an alloy thereof into a film is provided. The work roller is a cylindrical core defining a central axis, wherein the core has an outer surface forming a lamination surface; a first truncated conical portion extending from a first end of the core; and a second truncated conical portion extending from a second end of the core. Subsequently, the central axis is straight, and the angle between the outer surface of the core and the outer surface of each of the first and second truncated conical portions is less than 0.05 degrees. The width of the core is greater than the width of each of the first and second truncated conical portions. The width of the core is less than the sum of the widths of the first and second portions.

[0029] In some embodiments of the technology of the present invention, the angle is less than 0.03 degrees.

[0030] In some embodiments of the technology of the present invention, the angle is less than 0.02 degrees.

[0031] In some embodiments of the technology of the present invention, the angle is greater than 0.01 degrees.

[0032] In some embodiments of the technology of the present invention, the central part, the first truncated cone portion, and the second truncated cone portion have a chrome coating.

[0033] In some embodiments of the technology of the present invention, the chrome coating is a hard chrome coating.

[0034] In some embodiments of the technology of the present invention, the center, the first truncated cone portion and the second truncated cone portion have surface roughness in the range of 0.025 micron Ra to 0.5 micron Ra.

[0035] In some embodiments of the technology of the present invention, the range is 0.05 micron Ra to 0.3 micron Ra.

[0036] In some embodiments of the technology of the present invention, the first and second truncated conical portions are tapered as they extend away from the center.

[0037] In some embodiments of the technology of the present invention, a first shoulder is formed between the center and the first truncated cone portion. A second shoulder is formed between the center and the second truncated cone portion.

[0038] In some embodiments of the technology of the present invention, the first truncated cone portion tapers as the first truncated cone portion extends from its outer end toward the center. The second truncated cone portion tapers as the second truncated cone portion extends from its outer end toward the center.

[0039] For the purposes of this application, surface roughness is provided as a roughness average (Ra) expressed in metric units, particularly in microns, and angles are expressed in degrees (i.e., 360 degrees for a full rotation). For the purposes of this application, hardness indicates the resistance of a material (e.g., sheets and films) to local deformation induced by mechanical indentation or wear. For the purposes of this application, tensile strength (TS) refers to the capacity of a material (e.g., sheets and films) to resist a load that tends to elongate such a material. Tensile strength is measured by the maximum stress that the material can withstand while being elongated or pulled before it breaks.

[0040] The term “about” is used herein, expressly or implicitly; all quantities given herein are intended to refer to actual given values, and also to refer to approximations of such given values ​​that would be reasonably inferred based on the art of the art, including equivalent values ​​and approximations resulting from experiments and / or measurement conditions for such given values. For example, in the context of a given value or range, the term “about” refers to a value or range that is within 20%, preferably within 15%, more preferably within 10%, more preferably within 9%, more preferably within 8%, more preferably within 7%, more preferably within 6%, and more preferably within 5% of the given value or range.

[0041] Each embodiment of the technology of the present invention has at least one of the aforementioned purpose and / or aspects, but is not required to have all of them. It should be understood that some aspects of the technology of the present invention arising from an attempt to achieve the aforementioned purpose may not satisfy this purpose and / or may satisfy other purposes not specifically mentioned herein.

[0042] Additional and / or alternative features, aspects, and advantages of embodiments of the technology of the present invention will become apparent from the following description, the accompanying drawings, and the appended claims. Brief explanation of the drawing

[0043] For a better understanding of the technology of the present invention, as well as other embodiments and additional features thereof, the following description, used in conjunction with the accompanying drawings, is referenced, wherein: FIG. 1 is a schematic side cross-sectional view of a rolling mill and associated components for laminating lithium or lithium alloy sheets into a thin film. FIG. 2 is a schematic side view illustrating the main components of the rolling mill of FIG. 1 that enable control of the thickness and shape of the stacked lithium or lithium alloy film. Figure 3 is a schematic front view of the main components of the rolling mill of Figure 2. FIGS. 4a to 4c are schematic front views of the backup roller and work roller of FIG. 2 shown with different adjustments, where the angle of the truncated conical portion of the work roller and the degree of curvature of the work roller are exaggerated for illustrative purposes. Fig. 5 is a front view of one working roller of the rolling mill of Fig. 2. FIG. 6a is an enlarged view of Section 6 of FIG. 5 according to one embodiment of the roller of FIG. 5. FIG. 6b is an enlarged view of Section 6 of FIG. 5 according to another embodiment of the roller of FIG. 5. Figure 7 is a schematic cross-sectional profile of a lithium or lithium alloy sheet supplied to the rolling mill of Figure 2. FIG. 8 is a perspective view of a laminated lubricant distribution unit for lubricating the upper work roller of the rolling mill of FIG. 1. FIG. 9 is a perspective view of a laminated lubricant distribution unit for lubricating the lower working roller of the rolling mill of FIG. 1. Fig. 10 is a plan view of the laminated lubricant dispensing unit of Fig. 9. Fig. 11 is a front view of the laminated lubricant dispensing unit of Fig. 9. FIG. 12 is a cross-sectional view of the laminated lubricant dispensing unit of FIG. 9 taken through line 12-12 of FIG. 10. Figure 13 is an enlarged view of part 13 of Figure 12. Specific details for implementing the invention

[0044] FIG. 1 schematically illustrates a rolling mill (10) and associated components configured to produce a lithium or lithium alloy thin film (12) with a thickness of less than 100 microns from a pre-extruded lithium or lithium alloy sheet (14) with a thickness of about 100 to 500 microns. Although embodiments of the technology of the present invention will be described in relation to the production of a lithium or lithium alloy thin film (12) from a lithium or lithium alloy sheet (14), it is considered that at least some aspects of the technology of the present invention may be used for the production of other alkali metal or alkali metal alloy thin films from other alkali metal or alkali metal alloy sheets.

[0045] The rolling mill (10) comprises a main frame (16), a pair of work rollers (18a, 18b), a backup roller (20a) adjacent to and in contact with the work roller (18a), a backup roller (20b) adjacent to and in contact with the work roller (18b), a lamination lubricant dispensing unit (22) for dispensing lubricant onto the work roller (18a), and a lamination lubricant dispensing unit (200) for dispensing lubricant onto the work roller (18a). As can be seen, the work roller (18a) is positioned below the work roller (18b). The work rollers (18a, 18b) and the lamination lubricant dispensing unit (22, 200) will be described in more detail below. The work rollers (18a, 18b) and the backup rollers (20a, 20b) are rotatably mounted on a support frame (50, 52) (Fig. 2) as described in more detail below.

[0046] A roll (24) of a wound-extruded lithium or lithium alloy sheet (14) is placed on a feed roller (26) which includes a drive motor control unit (not shown) configured to control the tension of the lithium sheet (14) before reaching the work rollers (18a, 18b). The sheet (14) travels along its path through a series of free rollers (28) leading to an encoder roller (41) that measures the precise speed of the moving sheet (14) and a tension roller (43) equipped with a load cell configured to precisely measure the tension of the sheet (14) entering the stacking device (10). The load cell of the tension roller (43) may be electronically coupled to the control unit of the drive motor of the roll (24) to automatically adjust the tension applied to the sheet (14). The sheet (14) is then fed to a straightener (30) that rapidly winds the sheet (14) through a series of tightly packed rollers (32) which have the effect of eliminating lateral displacement of the sheet (14) and preventing zigzag movement of the sheet (14), thereby ensuring that the sheet (14) is fed straight to the center of the work rollers (18a, 18b) without any lateral weaving movement that would be disadvantageous to the lamination process. Thus, the sheet (14) is fed into the work rollers (18a, 18b) at a fixed position between the rollers (18a, 18b).

[0047] At the inlet of the rolling mill (10), a lubricant distribution unit (22, 200) discharges a suitable amount of lithium-compatible lamination lubricant onto the working surface of each work roller (18a, 18b) upstream from the lamination area so that the sheet (14) is laminated onto the properly lubricated work roller (18a, 18b), thereby preventing undesirable adhesion of the lamination film (12) on either of the work rollers (18a, 18b). One suitable lubricant is described in U.S. Patents No. 5,837,401 and No. 6,019,801, the entire contents of which are incorporated herein by reference. In one embodiment, the lubricant is based on toluene, hexane, and polyoxyethylene distearate and is used in sufficient amounts on each work roller (18a, 18b) to prevent excessive adhesion of the lamination film (12) on either of them.

[0048] The sheet (14) passes between two work rollers (18a, 18b), where its thickness is reduced from about 100 to 500 microns to about 20 to 100 microns depending on the desired final thickness of the film (12). Pressure is applied to the work rollers (18a, 18b) by backup rollers (20a, 20b), which then applies sufficient pressure to the sheet (14) to reduce its thickness and deform it into the film (12). Instead of being applied directly to the work rollers (18a, 18b), the lamination pressure is applied through the backup rollers (20a, 20b) to help avoid any unwanted bending of the work rollers (18a, 18b) that would be reflected in the shape and thickness of the film (12). As described below, the surface roughness of the work rollers (18a, 18b) must be minimal to produce a high-quality thin film (12). The pressure applied to the work rollers (18a, 18b) by the backup rollers (20a, 20b) is uniformly distributed on the surface of each roller (18a, 18b), thereby preserving the shape of the work rollers (18a, 18b). However, if the work rollers (18a, 18b) are sufficiently rigid, the required pressure to reduce the thickness of the sheet (14) and transform it into a film (12) may be applied directly by the work rollers (18a, 18b) without the use of any backup rollers. It is also considered that multiple backup rollers may be used to apply uniform pressure to each work roller (18a, 18b). For example, two pairs of backup rollers may be positioned on both sides of the work rollers (18a, 18b).

[0049] The laminated film (12) is driven through an optical refractory system (36), which measures the uniformity of the surface of the film (12) and also detects any porosity on the film (12) and cracks along the edges of the film (12). An optical system may also be used to measure the thickness of the film (12). Controlled tension is applied to the film (12) by a driven winding roller (38) to ensure that the film (12) is properly wound. Before reaching the winding roller (38), the laminated film (12) travels along its path under controlled tension through a series of rollers. The first of these rollers is a tension roller (45) equipped with a load cell configured to precisely measure the tension on the laminated film (12) as it exits the rolling mill (10). The load cell of the tension roller (45) may be electronically coupled to the control unit of the drive motor of the winding roller (38) to automatically adjust the tension applied to the sheet (12). The film (12) then passes through an encoder roller (47) that measures the exact speed of the moving film (12). The film (12) then passes through a series of free rollers (34) leading to a winding roller (38).

[0050] A thin insulating film (90), such as a polypropylene film, is also wound around a winding roller (38) to separate the layers of the film (12) so that they do not adhere to each other. The insulating film (90) is pulled from the roll (92) by the winding roller (38). From the roll (92), the insulating film (90) passes through a tension roller (94) before reaching the roller (38). The tension roller (94) is equipped with a load cell configured to precisely measure the tension on the insulating film (90). This tension measurement is used to control the tension applied to the film (12) by the winding roller (38) because the tension applied by the winding roller (38) is divided between the film (12) and the insulating film (90).

[0051] The encoder rollers (41, 47) each measure the speed of the sheet (14) entering the rolling mill (10) and the speed of the laminated film (12) exiting the rolling mill (10). The relationship between the entry speed of the sheet (14) and the exit speed of the laminated film (12) is directly proportional to the reduction in thickness from the initial sheet (14) to the film (12). In this way, the thickness of the laminated film (12) may be mathematically determined when the thickness of the initial sheet (14) is recognized. Accordingly, the thickness of the laminated film (12) is controlled and verified through the difference in speed between the speeds measured by the encoder rollers (41, 47). It is considered that the thickness of the laminated film (12) can be controlled and verified differently.

[0052] In one embodiment, the lamination process is performed in an anhydrous atmosphere containing less than 1% relative humidity to prevent any unwanted chemical reaction between water particles and the lithium film (12) that would make the lithium film (12) unsuitable for use in an electrochemical cell.

[0053] Now, referring to FIGS. 2 and FIGS. 3, the main components of a rolling mill (10) that enable control of the thickness and shape of the laminated film (12) will be described. It should be understood that the illustrated rolling mill (10) is one exemplary embodiment of a rolling mill configured to control the shape and thickness of the laminated film (12), and that other embodiments are considered. For example, the support members and the frame may have different configurations, and various hydraulic system configurations may be used.

[0054] Backup rollers (20a, 20b) are each rotatably mounted on the bearings of the support frames (50, 52). The support frame (52) is slidably mounted on the vertical member of the main frame (16) via any suitable means, such as a sliding channel or a bearing. The support frame (50) is fixedly mounted on the vertical member of the main frame (16). Thus, the support frame (52) may move vertically. The work rollers (18a, 18b) are each driven by an electric or hydraulic motor (not shown). The work rollers (18a, 18b) drive the backup rollers (20a, 20b) by friction. A pair of hydraulic linear actuators (66) are mounted on the upper horizontal member of the main frame (16). The hydraulic actuators are connected to the support frame (52). The hydraulic linear actuator (66) controls the vertical movement of the support frame (52) as well as the pressure applied to the work rollers (18a, 18b). The work rollers (18a, 18b) are each rotatably mounted on the support members (54, 56). The support members (54, 56) are each operably connected to the support frames (50, 52). The ends (58, 59) of the support members (54) are operably connected to the support frame (50) via a pair of hydraulic linear actuators (60, 61), and the ends (62, 63) of the support members (56) are operably connected to the support frame (52) via a pair of hydraulic linear actuators (64, 65).

[0055] During operation, the lamination speed is set by the speed of the work rollers (18a, 18b). The pressure (P) required to reduce the thickness of the film (12) to a desired thickness is adjusted through a hydraulic valve controlling the hydraulic linear actuator (66). The backup roller (20b) transmits the pressure (P) to the work roller (18b). Once the desired pressure (P) is set, the final shape of the laminated film (12) is finely adjusted by adjusting the fluid pressure for each hydraulic linear actuator (60, 61, 64, 65), thereby adjusting the force applied to the support members (54, 56) by each hydraulic linear actuator (60, 61, 64, 65) as described in more detail below. The hydraulic linear actuators (60, 61, 64, 65, 66) may be replaced with other types of actuators capable of generating sufficient force, such as electric actuators. In an alternative embodiment, additional hydraulic linear actuators are connected between the support members (54, 56). In this embodiment, the hydraulic linear actuators (60, 61, 64, 65, 66) are used to push the support members (54, 56) toward each other, and additional hydraulic linear actuators are used to push the support members (54, 56) toward each other.

[0056] During the lamination process, heat accumulates within the work rollers (18a, 18b) through friction generated on the lamination surface, having the effect of slightly expanding the work rollers (18a, 18b). An expansion of the work rollers (18a, 18b) by several microns in the lamination zone is sufficient to produce a film (12) of non-uniform thickness that is unsuitable for thin-film electrochemical cells. To alleviate this problem and help ensure a film (12) of uniform thickness, the center (100) (Fig. 4a) of the expanded work rollers (18a, 18b) is adjusted by bending the work rollers (18a, 18b) to straighten the center (100) and produce a lithium film (12) of uniform thickness. This control process will be described below in relation to Figs. 4a through 4c. It should be noted that the shape of the work rollers (18a, 18b) shown in FIGS. 4a to 4c is greatly exaggerated for clarity, but it should be understood that the tapering and curved profiles of the ends of the work rollers (18a, 18b) are not actually visible to the naked eye because they represent only a few microns of deviation from a perfect linear profile.

[0057] FIG. 4a illustrates the work rollers (18a, 18b) in a neutral position. The backup rollers (20a, 20b) apply pressure (P) sufficient to reduce the thickness of the sheet (14) to the desired thickness of the film (12) onto the work rollers (18a, 18b), while no lateral force is applied to the support members (54, 56) of the work rollers (18a, 18b).

[0058] In FIG. 4b, the backup rollers (20a, 20b) still apply pressure (P) sufficient to reduce the thickness of the sheet (14) to the desired thickness of the film (12) onto the work rollers (18a, 18b). However, due to thermal expansion, the center of the work rollers (18a, 18b) expands through heat accumulation caused by friction of the center (100) against the sheet (14). To compensate for this thermal expansion that deforms the work rollers (18a, 18b), an inwardly oriented lateral force (Fx) is applied to the support members (54, 56). The lateral force (Fx) causes the work rollers (18a, 18b) to bend slightly outward, thereby flattening the center (100) as shown in FIG. 4b. The outer edges of the work rollers (18a, 18b) are bent inward to straighten the center (100). Thus, the resulting laminated film (12) will have a flat and uniform thickness. The thermal expansion of the work rollers (18a, 18b) is also partially offset by the application of a lamination lubricant on the work rollers (18a, 18b). It is also considered that additional means of cooling the work rollers (18a, 18b) may be used to help offset the thermal expansion of the work rollers (18a, 18b).

[0059] When the edge of the sheet (14) being laminated is thicker than the center, more pressure must be applied by the work rollers (18a, 18b) to the outer edge of the sheet (14) and thus to the outer edge of the center (100) in order to laminate a film (12) having a uniform thickness over its entire width. To this end, the same lateral force (Fx) is applied to the support members (54, 56) to slightly bend the outer edge of the work rollers (18a, 18b) inward and apply more pressure to the edge of the sheet (14) than to its center. As a result, the laminated film (12) has a uniform thickness over its entire width. As heat accumulates in the work rollers (18a, 18b) through friction of the center (100) against the sheet (14), the center of the work rollers (18a, 18b) expands slightly. To compensate for this thermal expansion that slightly increases the diameter of the center of the work rollers (18a, 18b), the lateral force (Fx) is proportionally reduced to keep the center (100) straight so that the resulting laminated film (12) has a uniform thickness over its entire width.

[0060] Sometimes, the central part of the sheet (14) being laminated may be thicker than its edge. In order to laminate a film (12) having a uniform thickness over its entire width, more pressure must be applied by the work rollers (18a, 18b) to the central part of the sheet (14) and thus to the central part of the center (100). As shown in FIG. 4c, for this purpose, an outwardly oriented lateral force (Fy) is applied to the support members (54, 56). The lateral force (Fy) slightly bends the central part of the work rollers (18a, 18b) inwardly to press the central part of the center (100) inwardly, thereby applying more pressure to the central part of the sheet (14) and laminating a film (12) having a uniform thickness over its entire width.

[0061] In some situations, heat generated by friction of the center (100) against the sheet (14) accumulates on the outer part of the meeting surface of the work rollers (18a, 18b), causing them to expand and open a small gap within the center of the center (100). To compensate for this thermal expansion, an outwardly oriented lateral force (Fy) is applied to the support members (54, 56) of the work rollers (18a, 18b). The lateral force (Fy) slightly bends the center of the center (100) inward and straightens the center (100). The profile of the center (100) of the work rollers (18a, 18b) is bent back into a straight line so that the resulting laminated film (12) is flat and has a uniform thickness over its entire width.

[0062] Although only the symmetrical adjustment of the work rollers (18a, 18b) is illustrated in FIG. 4b and FIG. 4c, other adjustments are possible because the support members (54, 56) are independent of each other. For example, if the work rollers (18a, 18b) expand more on one side than on the other, the left or right support member (54, 56) may have a force (Fx or Fy) that exceeds the force (Fx or Fy) of the support member (54, 56) on the opposite side, thereby enabling multiple fine adjustments.

[0063] The adjustment of the shape of the center (100) combined with precise measurement of a suitable measuring device, such as an optical refractory system (36), enables the rolling mill (10) to manufacture a high-quality laminated film (12) in a thickness range of 20 to 100 microns, which exhibits a nearly constant thickness throughout its entire length and width.

[0064] The adjustment of the profile and thickness of the laminated film (12) may be performed by a field worker who fine-tunes the pressure applied by the backup rollers (20a, 20b) and the pressure applied to the support members (54, 56), or this work may be performed electronically by connecting the measurement readings and actuator controls that control the various pressures and forces of the backup rollers (20a, 20b) and the work rollers (18a, 18b) to a computer that provides real-time adjustment of these parameters.

[0065] Now, with reference to FIGS. 5 to 6b, the work roller (18a) will be described in more detail. In this embodiment, the work roller (18b) is identical to the work roller (18a), and thus the work roller (18b) will not be described separately in this specification. It is considered that the work roller (18b) may be partially different from the work roller (18a).

[0066] As described above, the work roller (18a) has a center (100). The center (100) is a cylindrical center (100). The outer surface (102) of the center (100) forms a lamination surface that is rolled over the sheet (14) during the lamination process. As such, the center (100) has a width (W1) that is slightly wider than the width (W2) (Fig. 7) of the sheet (14) to be laminated. The center (100) forms the central axis (104) of the work roller (18a).

[0067] The truncated cone portion (106) extends from the end of the center (100). The truncated cone portions (106) are mirror images of each other. In FIG. 5, the outer surface (110) of the truncated cone portion (106) does not appear to be tapered. This is because the tapering angle is very small and not visible to the naked eye. This angle is exaggerated in FIG. 6a and FIG. 6b, which illustrate two different embodiments of the work roller (18a) and will be described below. Each truncated cone portion (106) has a width (W3). The width (W1) of the center (100) is greater than the width (W3) of each truncated cone portion (106). The width (W1) of the center (100) is less than the sum of the widths (W3) of both truncated cone portions (106) (i.e., W1 < W3 + W3). In some embodiments, the width (W1) is 125 mm to 210 mm and the width (W3) is 65 mm to 110 mm.

[0068] In one embodiment illustrated in FIG. 6a, the truncated cone portions (106) are tapered as they extend apart from the center (100). This embodiment is illustrated in FIG. 4a through 4c, where the tapering is exaggerated. In this embodiment, a shoulder (108) is formed between the center (100) and each truncated cone portion (106) (illustrated for one truncated cone portion in FIG. 6a). In some embodiments, the shoulder (108) has a height (H1) of less than 0.05 mm. In some embodiments, the height (H1) is less than 0.02 mm. The shoulder (108) is considered to be omitted. When the central axis (104) is straight (i.e., when the work roller (18a) is in the neutral position as in FIG. 4a), the angle (A) between the outer surface (102) of the center (100) and the outer surface (110) of the truncated cone portion (106) is less than 0.05 degrees. In some embodiments, the angle (A) is less than 0.03 degrees. In some embodiments, the angle (A) is less than 0.02 degrees. In some embodiments, the angle (A) is less than 0.02 degrees and greater than 0.01 degrees. In some embodiments, the center (100) has a diameter (D1) of 70 mm to 90 mm. In some embodiments, the difference between the minimum diameter (D2) and the maximum diameter (D3) of each truncated cone portion (106) is 0.03 mm to 0.17 mm. The profile of the work rollers (18a, 18b) according to this embodiment facilitates their bending by providing a free zone (84) (Fig. 4a) between the truncated conical portions (106) and a free zone (85) (Fig. 4a) between the truncated conical portions (106) and the backup rollers (20a, 20b), thereby allowing the ends of the work rollers (18a, 18b) to move and bend the center (100) as desired. The free zone (84) also allows excess lamination lubricant to be discharged laterally during the lamination process.The work roller (18a) of the embodiment shown in FIG. 6a can be used with sheets (14) having a number of different profiles thanks to the adjustments that can be made in the rolling mill (10) (as described above in relation to FIG. 4a through 4c), but this embodiment of the work roller (18a) is particularly suitable for laminating sheets (14) extruded into a central portion (112) having a height (H2) (Fig. 7) smaller than the height (H3) (Fig. 7) of the side portion (114). Again, in FIG. 7, the heights (H2, H3) do not appear different because the difference is not visible to the naked eye. In some embodiments, the height (H2) is less than 15 microns smaller than the height (H3).

[0069] In another embodiment illustrated in FIG. 6b, each truncated cone portion (106) tapers as it extends from its outer end toward the center (100) (i.e., D2 is greater than D3). When the center axis (104) is straight (i.e., when the work roller (18a) is in the neutral position), the angle (B) between the outer surface (102) of the center (100) and the outer surface (110) of the truncated cone portion (106) is less than 0.05 degrees. In some embodiments, the angle (B) is less than 0.03 degrees. In some embodiments, the angle (B) is less than 0.02 degrees. In some embodiments, the angle (B) is less than 0.02 degrees and greater than 0.01 degrees. In some embodiments, the center (100) has a diameter (D1) of 70 mm to 90 mm. In some embodiments, the difference between the maximum diameter (D2) and the minimum diameter (D3) of each truncated conical portion (106) is 0.03 mm to 0.17 mm. Although the work roller (18a) of the embodiment shown in FIG. 6b can be used with sheets (14) having a number of different profiles due to adjustments that can be made in the rolling mill (10) (as previously described in relation to FIG. 4a through 4c), this embodiment of the work roller (18a) is particularly suitable for laminating sheets (14) extruded into a central portion (112) having a height (H2) (Fig. 7) greater than the height (H3) (Fig. 7) of its side portion (114). In some embodiments, the height (H2) is less than 15 microns greater than the height (H3).

[0070] Returning to FIG. 5, the work roller (18a) has a support shaft (116, 118) extending from the end of the truncated conical portion (106). The support shaft (116, 118) is received within a bearing (not shown) for rotatably mounting the work roller (18a) to a support member (54) (or a support member (56) for the work roller (18b)). The support shaft (118) has an extension (120) configured for connection to a motor driving the work roller (18b). The portion (100, 106) and the support shaft (116, 118) are formed integrally.

[0071] As described above, the lamination lubricant distributed on the work rollers (18a, 18b) helps prevent the lithium film (12) from adhering to the work rollers (18a, 18b), causing the film (12) to pass straight through the work rollers (18a, 18b). The use of the lubricant makes it possible to laminate lithium and lithium alloys onto work rollers (18a, 18b) made of materials that would generally not be suitable due to their adhesion to lithium. The lubricant nullifies these limitations. Therefore, for large-scale manufacturing, the work rollers (18a, 18b) are preferably made of durable hard materials such as steel or stainless steel or even ceramic. In some embodiments, the steel or stainless steel rollers (18a, 18b) have a thin chrome coating for added hardness. The chrome coating is applied to at least the center (100) and the truncated conical portion (106) of the work rollers (18a, 18b). In some embodiments, the chrome coating is a hard chrome coating. In order to provide a desired surface finish for the film (12) and to allow some adhesion of the laminated lubricant onto the work rollers (18a, 18b), in some embodiments, the outer surfaces (102, 110) of the center (100) and the truncated conical portion (106) have a surface roughness in the range of 0.025 micron Ra to 0.5 micron Ra. In other embodiments, the surface roughness is in the range of 0.05 micron Ra to 0.30 micron Ra.

[0072] Now, with reference to FIG. 8, the laminated lubricant distribution unit (22) will be described in more detail. The laminated lubricant distribution unit (22) includes four nozzles (150) mounted on the rail (152). It is considered that the laminated lubricant distribution unit (22) may have more than or fewer than four nozzles (150). The laminated lubricant is supplied to a passage (not shown) inside the rail (152) through an intake connector (154). The intake connector (154) is fluidly connected to a pump (not shown) that supplies lubricant from a lubricant reservoir (not shown) containing the laminated lubricant inside it to the intake connector (154). The four nozzles (150) are fluidly connected to the passage inside the rail (152). As can be seen in FIG. 1, the laminated lubricant distribution unit (22) is positioned upstream of the lamination area and spaced apart from the work roller (18b). The lamination lubricant dispensing unit (22) is positioned on the central axis (104) of the work roller (18b) and is shaped such that the nozzle (150) continuously sprays the lamination lubricant onto the lamination surface of the work roller (18b). The spray from the nozzle (150) covers an area slightly wider than the lamination surface.

[0073] Each nozzle (150) has a nozzle body (156), a filter, a nozzle head (158), and a nut (160). The nozzle body (156) is screwed into a rail (152). A filter is placed inside the nozzle body (156). A nozzle head (158) forms a spray hole (162) and is placed on the end of the nozzle body (156). A nut (160) is placed on the nozzle body (156) and is screwed onto the nozzle body (156) to hold the nozzle head (158) and the filter in place.

[0074] Now, with reference to FIGS. 9 through 13, a laminated lubricant dispensing unit (200) will be described. In this embodiment, the laminated lubricant dispensing unit (200) is manufactured from a single electrostatically dispersed acetal copolymer. It is considered that other types of materials, such as polyamide, polypropylene, polyethylene, acrylonitrile butadiene styrene, polyethylene terephthalate, polystyrene, thermoplastic polyurethane, poly(methyl methacrylate), polyvinyl chloride, brass, and aluminum, may be used. Other materials are also considered. It is also considered that the laminated lubricant dispensing unit (200) may be manufactured from a number of parts joined together or otherwise connected.

[0075] The laminated lubricant dispensing unit (200) has a dispensing unit body (202). Each rear corner portion of the dispensing unit body (202) forms two holes (206). A fastener (not shown) is received in the holes (206) to fasten the dispensing unit body (202) to the frame (16) of the rolling mill (10) at a position between the work roller (18a) and the straightener (30). The dispensing unit body (202) forms a wall (208) extending laterally. A single lubricant passage (210) is formed within the dispensing unit body (202), as best illustrated in FIG. 12. The lubricant passage (210) has an inlet (not shown) formed in the rear wall (214) of the dispensing unit body (202) and an outlet (216) formed in the wall (208) extending laterally. As can be seen, the outlet (216) is laterally centered on the laterally extending wall (208) and is positioned at the bottom thereof. A plurality of lubricant passages (210) may be formed in the distribution unit body (202), and it is considered that the outlets of these passages are located at different positions along the laterally extending wall (208). It is also considered that at least some of these plurality of lubricant passages (210) may have a common inlet.

[0076] Two side walls (218) extend forward from a wall (208) that extends laterally. As can be seen in FIG. 10, the side walls (218) are parallel to each other. As can be seen in FIG. 12, the front end (220) of the side wall (218) is angled from the vertical so as not to interfere with the work roller (18a).

[0077] The laminated lubricant dispensing unit (200) also has a leg (222). The leg (222) is connected to the lower end of the laterally extending wall (208) and extends forward from there. The leg (222) is also connected to the lower end of the side wall (218) and extends between them. The leg (222), the side wall (218), and the laterally extending wall (208) together form a recess (224) having an open side at the front of the laminated lubricant dispensing unit (200). As can be seen in FIG. 12, the leg (222) has a front edge (226) that abuts the laminated surface of the work roller (18a) at a position vertically below the central axis (104) of the work roller (18a). The front edge (226) has a width (W4) (Fig. 10) greater than the width (W1) of the laminated surface of the work roller (18a) to help ensure that the laminated lubricant is applied across the entire width of the laminated surface.

[0078] Referring to FIG. 13, the leg (222) has an angled portion (228) that extends upward and backward toward a wall (208) extending laterally from a front edge (226). The corner (230) between the angled portion (228) and the front edge (226) is arched. In some embodiments, the angled portion (228) extends at an angle (C) of 5 to 25 degrees from the horizontal. In some embodiments, the angle (C) is 10 to 20 degrees from the horizontal. The leg (222) also has a generally horizontal portion (232) that extends between the angled portion (228) and the wall (208) extending laterally. The portion (232) is horizontal when viewed from the side (i.e., as seen in FIG. 12 and FIG. 13). However, from the front view of part (232) (i.e., as seen in FIG. 11), part (232) is sloped slightly downward on both sides of its lateral center, which thus corresponds to the apex of part (232). In some embodiments, the angle (D) (Fig. 11) between the surfaces on both sides of the lateral center of part (232) is greater than 180 degrees and less than 185 degrees, and in some embodiments, less than 182 degrees. It is also considered that part (232) may also be flat (i.e., the angle (D) is 180 degrees) when viewed from the front view of part (232) (i.e., as seen in FIG. 11). As can be seen in FIGS. 11 and 12, the outlet (216) of the lubricant passage (210) is laterally aligned with the apex of the portion (232), and the bottom of the outlet (216) is vertically aligned with the upper part of the portion (232) of the adjacent leg (222). It is considered that the portion (232) may be omitted and the angular portion (228) may be extended to a wall (208) extending laterally from the front edge (226).

[0079] A gutter (234) extending laterally is formed in the angular portion (228) of the ledge (222). As can be seen best in FIG. 10, the end of the gutter (234) is spaced apart from the side wall (218). The gutter (234) is spaced apart from the front edge (226) of the ledge (222). As can be seen in FIG. 13, the gutter (234) is closer to the front edge (226) than to the portion (232) of the ledge (222).

[0080] Referring to FIG. 12, the inlet of the lubricant passage (210) is fluidly connected to a pump (236) that is fluidly connected to a lubricant reservoir (238). The lubricant reservoir (238) holds the laminated lubricant inside. The lubricant reservoir (238) is also considered to be usable to supply the laminated lubricant to the aforementioned laminated lubricant distribution unit (22). The pump (236) pumps the laminated fluid from the lubricant reservoir (238) into the lubricant passage (210). From the outlet (216) of the lubricant passage (210), the lubricant flows forward and laterally (due to the angle (D)) along the portion (232) of the reg. The lubricant then flows downward along the angular forming portion (228). A portion of the lubricant will flow into the gutter (234), which helps ensure a uniform distribution of the lubricant across the width of the reg (222). The lubricant then flows to the forward edge (226), where it comes into contact with the lamination surface of the work roller (18a). The upward moving lamination surface of the work roller (18a) picks up the lubricant to effectively coat the lamination surface that will come into contact with the sheet (14).

[0081] In some embodiments, the alkali metal or alkali metal alloy film of the present invention is a laminated lithium film or laminated lithium alloy film obtained using a rolling mill and a working roller as defined herein.

[0082] The lithium alloys that may be used to prepare the film of the technology of the present invention include, but are not limited to, lithium-silicon, lithium-aluminum, lithium-magnesium, lithium-strontium, lithium-barium, etc.

[0083] The lithium or lithium alloy film of the present invention comprises a predetermined amount of a metal element. The addition of the metal element to the lithium or lithium alloy film allows for a reduction in the overall thickness of the film and an improvement in its overall mechanical strength. In some cases, the metal element is present in the lithium or lithium alloy film in an amount that improves mechanical strength across the width, thickness, and length of the film.

[0084] The metal element that may be used in the preparation of the lithium or lithium alloy film of the technology of the present invention is preferably electrically conductive. It should be understood that the presence of the metal element should not interfere with the electrical conductivity of the lithium or lithium alloy film. For example, aluminum is a metal element that may be used in the lithium or lithium alloy film. In some cases, aluminum is present in the film in amounts ranging from about 3,000 ppm to about 10,000 ppm, or about 3,000 ppm to about 9,000 ppm, or about 3,000 ppm to about 8,000 ppm, or about 3,000 ppm to about 7,000 ppm, or about 3,000 ppm to about 6,000 ppm, or about 3,000 ppm to about 5,000 ppm. In some cases, aluminum is present in the film in amounts greater than 3,000 ppm.

[0085] In some cases, the lithium or lithium alloy film of the present invention has a hardness as measured by a Shore hardness tester (Shore A scale) in the range of about 50 to about 85, or about 60 to about 80, or about 60 to about 75, or about 50 to about 70, or about 60 to about 75, or about 65 to about 75, or about 66 to 70, or about 66 to 69. In some cases, the hardness is at least 65. In some other cases, the hardness is at least about 66. In some cases, the hardness is uniform throughout the entire lithium or lithium alloy film.

[0086] A lithium film obtained by the technology defined in this specification has a width (corresponding to the distance from one edge of the film to another) in the range of about 140 mm to about 200 mm, or about 150 mm to about 200 mm, or about 160 mm to about 180 mm, or about 160 mm to about 175 mm, or about 160 mm to about 170 mm, or about 160 mm to 165 mm, and has a thickness in the range of about 20 microns to about 100 microns, or 20 microns to about 90 microns, or about 20 microns to about 75 microns, or about 20 microns to about 50 microns, or about 20 microns to 30 microns. The thickness of the lithium or lithium alloy film is uniform over the entire width of the film. The uniform thickness across the entire width of the film includes a thickness variation of approximately + / -2 microns.

[0087] In some embodiments, the lithium or lithium alloy film obtained by the technique defined herein is about 1 × 10⁻⁶ -4 Up to about 7×10 -4 It has a thickness-to-width (t / w) ratio. In some cases, this t / w ratio is maintained over the entire length of the film.

[0088] In particular, the technology of the present invention allows the width, thickness, and hardness of a lithium or lithium alloy film to be maintained over an extended film length. For example, the lithium or lithium alloy film of the technology of the present invention maintains its width, thickness, and hardness over at least about 15,000 meters, over at least about 10,000 meters, over at least about 9,000 meters, over at least 8,000 meters, over at least 7,000 meters, over at least 6,000 meters, over at least 5,000 meters, over at least 4,000 meters, over at least 3,000 meters, over at least 2,000 meters, or over at least 1,000 meters.

[0089] yes

[0090] The following examples are provided to illustrate the implementation of various embodiments of the technology of the present invention. They are not intended to limit or define the entire scope of the technology of the present invention. It should be understood that the technology of the present invention is not limited to the specific embodiments described and illustrated herein, but includes all modifications and variations that fall within the scope of the present disclosure as defined in the appended embodiments.

[0091] Example 1 - Preparation of laminated lithium alloy film (3000 ppm)

[0092] A laminated lithium film was manufactured using a rolling mill including a work roller as defined in this specification. The obtained lithium film had a width of 170 mm, a thickness of 60 microns, and an aluminum content of 3000 ppm. The hardness of the film was evaluated using a Shore hardness tester (PTC Model 320 - A scale). The results are presented in Table 1.

[0093] Hardness of laminated LiAl film (3000 ppm Al) Sample Hardness (Shore A) 1 66 2 66 3 66 4 66 5 66

[0094] Example 2 - Preparation of laminated lithium alloy film (5000 ppm)

[0095] A laminated lithium film was manufactured using a rolling mill including a work roller as defined in this specification. The obtained lithium film had a width of 170 mm, a thickness of 60 microns, and an aluminum content of 5000 ppm. The hardness of the film was evaluated using a Shore hardness tester (PTC Model 320 - A scale). The results are presented in Table 2.

[0096] Hardness of LiAl film (5000 ppm Al) Sample Hardness (Shore A) 1 68 2 69 3 68 4 68 5 67

[0097] Example 3 - Evaluation of Tensile Strength of Laminated Lithium Alloy Film (3000 ppm)

[0098] A laminated lithium-aluminum film was manufactured using a rolling mill including a work roller as defined herein. The lithium film had a width of 170 mm, a thickness of 60 microns, and an aluminum content of 3000 ppm. The tensile strength of the lithium film was evaluated using a testometric M500 25 kN. The results are presented in Table 3.

[0099] Tensile strength of LiAl film (3000 ppm Al) at 10 mm / min Sample UTS kgf / cm 2 UTS mpa 1 20.23 1.98 2 19.56 1.91 3 19.57 1.91 4 21.08 2.06 5 19.98 1.96

[0100] Example 4 - Evaluation of Tensile Strength of Laminated Lithium Alloy Film (5000 ppm)

[0101] A laminated lithium-aluminum film was manufactured using a rolling mill including a work roller as defined herein. The lithium film had a width of 170 mm, a thickness of 60 microns, and an aluminum content of 5000 ppm. The tensile strength of the lithium film was evaluated using a testometric M500 25 kN. The results are presented in Table 4.

[0102] Tensile strength of LiAl film (5000 ppm Al) at 10 mm / min Sample UTS kgf / cm 2 UTS mpa 1 23.41 2.30 2 22.52 2.20 3 22.63 2.21 4 23.47 2.30 5 23.28 2.28

[0103] Modifications and improvements to the aforementioned embodiments of the technology of the present invention may be apparent to those skilled in the art. The foregoing description is intended to be illustrative rather than limiting. Accordingly, the scope of the technology of the present invention is intended to be limited only by the scope of the appended claims.

Claims

Claim 1 A rolling mill for laminating sheets of alkali metal or its alloy into a film, comprising: a frame; a first work roller rotatably mounted on the frame; a second work roller rotatably mounted on the frame, wherein the first and second work rollers are positioned to receive a sheet between them; at least two first actuators operably connected to opposite ends of the first work roller to bend the first work roller; and at least two second actuators operably connected to opposite ends of the second work roller to bend the second work roller, wherein each of the first and second work rollers comprises: a cylindrical center defining a central axis, wherein the center has an outer surface forming a lamination surface; and a first truncated conical portion extending from a first end of the center. A rolling mill comprising a second truncated cone portion extending from a second end of a center, wherein when the central axis is straight, the angle between the outer surface of the center and the outer surface of each of the first and second truncated cone portions is less than 0.05 degrees, the width of the center is greater than the width of each of the first and second truncated cone portions, the width of the center is less than the sum of the widths of the first and second truncated cone portions, the first and second truncated cone portions are tapered as they extend spaced apart from the center, a first shoulder is formed between the center and the first truncated cone portion, said first shoulder extends radially inward from a first end of the center to an inner end of the first truncated cone portion, and a second shoulder is formed between the center and the second truncated cone portion, said second shoulder extends radially inward from a second end of the center to an inner end of the second truncated cone portion. Claim 2 A rolling mill according to paragraph 1, wherein the angle is less than 0.03 degrees. Claim 3 In paragraph 2, a rolling mill in which the angle is less than 0.02 degrees. Claim 4 In paragraph 3, a rolling mill in which the angle exceeds 0.01 degrees. Claim 5 A rolling mill according to any one of claims 1 to 4, wherein for each of the first and second work rollers, the center, the first truncated conical portion and the second truncated conical portion have a chrome coating. Claim 6 A rolling mill according to any one of claims 1 to 4, wherein for each of the first and second work rollers, the center, the first truncated conical portion, and the second truncated conical portion have a surface roughness in the range of 0.025 micron Ra to 0.5 micron Ra. Claim 7 In paragraph 6, the range is 0.05 micron Ra to 0.3 micron Ra, rolling mill. Claim 8 A rolling mill according to any one of claims 1 to 4, further comprising: a first backup roller rotatably mounted on a frame, wherein the first backup roller contacts the first work roller to apply pressure on the first work roller; and a second backup roller rotatably mounted on a frame, wherein the second backup roller contacts the second work roller to apply pressure on the second work roller. Claim 9 A work roller for a rolling mill for laminating sheets of alkali metal or its alloy into a film, comprising: a cylindrical center defining a central axis, wherein the center has an outer surface forming a lamination surface; and a first truncated conical portion extending from a first end of the center. A work roller comprising a second truncated cone portion extending from a second end of a central portion, wherein when the central axis is straight, the angle between the outer surface of the central portion and the outer surface of each of the first and second truncated cone portions is less than 0.05 degrees, the width of the central portion is greater than the width of each of the first and second truncated cone portions, the width of the central portion is less than the sum of the widths of the first and second truncated cone portions, the first and second truncated cone portions are tapered as they extend away from the central portion, a first shoulder is formed between the central portion and the first truncated cone portion, said first shoulder extends radially inward from a first end of the central portion to an inner end of the first truncated cone portion, and a second shoulder is formed between the central portion and the second truncated cone portion, said second shoulder extends radially inward from a second end of the central portion to an inner end of the second truncated cone portion. Claim 10 In paragraph 9, a work roller, the angle being less than 0.03 degrees. Claim 11 In Clause 10, a work roller with an angle of less than 0.02 degrees. Claim 12 In Clause 11, a work roller whose angle exceeds 0.01 degrees. Claim 13 A work roller according to any one of claims 9 to 12, wherein the central part, the first truncated conical part, and the second truncated conical part have a chrome coating. Claim 14 A work roller according to any one of claims 9 to 12, wherein the center, the first truncated conical portion, and the second truncated conical portion have a surface roughness in the range of 0.025 micron Ra to 0.5 micron Ra. Claim 15 In Clause 14, the working roller, with a range of 0.05 micron Ra to 0.3 micron Ra. Claim 16 delete Claim 17 delete Claim 18 delete Claim 19 delete Claim 20 delete Claim 21 delete Claim 22 delete Claim 23 delete

Images