KR20230102481A - Li foil rolling apparatus and Li foil rolling method using thereof - Google Patents

Abstract

The present invention provides a lithium rolling device for rolling a lithium sheet to form a lithium foil, comprising: a first roll contacting a first surface of the lithium sheet; a second roll contacting the second surface of the lithium sheet; And a belt disposed at rear ends of the first roll and the second roll, at least a part of which is in surface contact with the second surface of the lithium foil to control the tension applied to the lithium foil and transport the lithium foil, It may include; a first conveyor device.

Description

Lithium rolling apparatus and lithium rolling method using the same

The present invention relates to a lithium rolling apparatus and a lithium rolling method using the same, and more particularly, to a lithium rolling apparatus for forming a lithium foil used as an anode material of a lithium secondary battery and a lithium rolling method using the same.

A lithium ion secondary battery is a secondary battery that has a high charge/discharge capacity and can achieve high output. Lithium ion secondary batteries are mainly used as power sources for mobile electronic devices, and are expected as power sources for electric vehicles in recent years. A lithium ion secondary battery has an active material capable of adsorbing and releasing lithium in a positive electrode and a negative electrode, respectively. In addition, the lithium ion secondary battery operates by the movement of lithium ions, which are charge carriers, in the electrolyte liquid existing between the two electrodes.

However, if necessary, lithium ions are introduced into objects such as active materials, electrodes, and lithium ion secondary batteries. Hereinafter, introducing lithium ions into the objects is referred to as doping with lithium. As such a doping method of lithium, there are an electrical doping method, a direct target doping method, and the like.

On the other hand, lithium is a relatively soft metal compared to other metals, and since the lithium sheet is excessively deformed during rolling, it is easy to cause mold collapse or damage to the lithium sheet after rolling. This is called a sticking phenomenon, and in fact, because of this, it is not easy to manufacture a thin and well-shaped lithium sheet by rolling.

The cause of the deformation of the lithium sheet is that a large force is applied to the lithium foil from the rolling roll during rolling, and when the shear plastic deformation due to the frictional force with the material exceeds the yield strength of the material, the lithium original foil is pressed against the roll. When the lithium source foil is pressed against a roll, it is difficult to remove the rolled lithium foil from the roll without deformation or breakage, and as a result, the product lithium foil tends to collapse or break in shape.

In some literature, a product lithium sheet for a negative electrode active material of a lithium battery is manufactured, and in order to solve the above problems, a rolling method in which an organic solvent for an electrolytic liquid is applied to the surface of a roll to reduce friction and prevent compression this is being proposed. At this time, since the organic solvent functions as a lubricant, it is possible to suppress damage to the lithium foil. In addition, a method of rolling in a state where a resin film is stacked on a lithium sheet has been proposed.

However, there is a problem in that it is difficult to control the sticking phenomenon in which the material adheres to the rolling roll in manufacturing the lithium foil only by using a lubricant and a resin film. In addition, when a very thin lithium foil is transferred, since the tension control applied to the lithium foil is sensitive, the lithium foil can be torn even if a strong tension is applied. It's hard to do.

The present invention has been devised to solve the above requirements, and a lithium rolling device capable of producing a very thin and wide lithium foil without deformation or damage of lithium foil used as an anode material of a lithium secondary battery, and a lithium rolling device that can manufacture the same. Its purpose is to provide a lithium rolling method using However, these tasks are illustrative, and the scope of the present invention is not limited thereby.

According to one embodiment of the present invention, a lithium rolling device for forming a lithium foil by rolling a lithium sheet is provided. The lithium rolling device includes a first roll contacting a first surface of the lithium sheet; a second roll contacting the second surface of the lithium sheet; And a belt disposed at rear ends of the first roll and the second roll, at least a part of which is in surface contact with the second surface of the lithium foil to control the tension applied to the lithium foil and transport the lithium foil, It may include; a first conveyor device.

In the lithium rolling device, the first conveyor device may further include a support for supporting the lithium foil and a driving unit for driving the belt.

In the lithium rolling device, when the lithium foil is conveyed by the first conveyor device, the lithium foil is formed on a portion that contacts the first surface of the lithium foil on the first conveyor device so that the lithium foil can be conveyed flat. A guide roll may be included.

The lithium rolling device may include a second conveyor device disposed above the first conveyor device and transporting the lithium foil in contact with the first surface of the lithium foil.

In the lithium rolling device, the first conveyor device and the second conveyor device may be driven at the same speed.

The lithium rolling device may include a third conveyor device disposed at the front ends of the first roll and the second roll to transfer the lithium sheet by contacting at least a portion of the second surface of the lithium sheet. can

In the lithium rolling device, the driving speed of the third conveyor device may be controlled equal to or slower than the driving speed of the first conveyor device.

The lithium rolling device may further include a fourth conveyor device disposed above the third conveyor device and transporting the lithium sheet by contacting the first surface of the lithium sheet.

In the lithium rolling device, the third conveyor device and the fourth conveyor device may be driven at the same speed.

In the lithium rolling device, the driving speed of the third conveyor device may be controlled equal to or slower than the driving speed of the first roll and the second roll.

In the lithium rolling device, in order to suppress a sticking phenomenon, a lubricant supply unit for spraying a lubricant on at least one surface of the lithium sheet before rolling by the first roll and the second roll may be included. there is.

In the lithium rolling device, the first roll, the second roll, and the belt may include a polymer material.

In the lithium rolling device, the polymer material may include any one of polyethylene, polypropylene, vinylidene, polyolefin, and polyester.

In the lithium rolling apparatus, a resin film may be further interposed on at least one surface of the lithium sheet that comes into contact with either one of the first roll and the second roll to suppress the sticking phenomenon of the lithium sheet there is.

In the lithium rolling device, the width of the belt of the first conveyor device is greater than the width of the lithium foil, and the lithium foil is in surface contact with the belt by the driving force of the belt at the same speed as the belt. can be transported

In the lithium rolling device, the driving speed of the first conveyor device may be controlled equal to or faster than the driving speeds of the first roll and the second roll.

According to another embodiment of the present invention, a lithium rolling method for forming a lithium foil by rolling a lithium sheet is provided. The lithium rolling method may include forming a lithium foil by rolling using a first roll in contact with a first surface of a lithium sheet and a second roll in contact with a second surface of the lithium sheet; and a first conveyor device disposed at rear ends of the first roll and the second roll, so that the belt provided in the first conveyor device and at least a portion of the second surface of the lithium foil come into surface contact to form the lithium foil. It may include; conveying while controlling the applied tension.

In the lithium rolling method, when the lithium foil is transported by the first conveyor device by a guide roll or a second conveyor device formed on a portion of the first conveyor device in contact with the first surface of the lithium foil, The tension applied to the lithium foil is controlled, and the lithium foil can be transferred flat.

In the lithium rolling method, the driving speed of the first conveyor device may be controlled equal to or faster than the driving speed of the first roll and the second roll.

According to one embodiment of the present invention made as described above, a lithium foil having a thickness of less than 100 um can be implemented using a lithium rolling device capable of forming a lithium foil used as an anode material of a lithium secondary battery. Of course, the scope of the present invention is not limited by these effects.

1 is a diagram schematically illustrating the structure of a lithium rolling device according to an embodiment of the present invention.
2 and 3 are cross-sectional and top views schematically illustrating the structure of a conveyor device provided in a lithium rolling device according to an embodiment of the present invention.
4 and 5 are cross-sectional views schematically illustrating the structure of a lithium rolling device according to another embodiment of the present invention.

Hereinafter, several preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

The embodiments of the present invention are provided to more completely explain the present invention to those skilled in the art, and the following examples may be modified in many different forms, and the scope of the present invention is as follows It is not limited to the examples. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the spirit of the invention to those skilled in the art. Hereinafter, embodiments of the present invention will be described with reference to drawings schematically showing ideal embodiments of the present invention.

1 is a diagram schematically illustrating the structure of a lithium rolling device according to an embodiment of the present invention.

Referring to FIG. 1 , a lithium rolling apparatus 100 according to an embodiment of the present invention has a rolling unit for forming a lithium foil by rolling a lithium sheet between a first roll 10A and a second roll 10B. A lubricant supply unit 30 capable of injecting lubricant onto the surface of the lithium sheet is disposed at the front end of the lithium sheet with respect to the rolling unit.

Although the sizes of the first roll 10A and the second roll 10B are shown to be the same, if necessary, the diameters of the first roll 10A and the second roll 10B may be differently disposed. In this case, the lithium sheet ( The lithium sheet 60 may be rolled by controlling the shear stress applied to 60). Here, specific details of the power control of the rolling roll are omitted as it is a known technique.

The form of the lubricant supply unit 30 may be a form of applying a droplet, a form of injecting a lubricant in a spray form, or a form of directly applying the lubricant to the surface of the lithium sheet using a brush or the like. Any one of organic solvents may be used as the lubricant, for example, pentane, hexane, heptane, octane, nonane, decane, ethyl methyl carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, fluoromethyl methyl carbonate, difluoro Romethyl methylcarbonate, 2,2,2-trifluoroethylmethylcarbonate, bis(2,2,2-trifluoroethyl) carbonate, acetonitrile, propionitrile, butyronitrile, acrylonitrile, dimethoxy Methane, 1,2-dimethoxyethane, tetrahydrofuran, 2-methyl tetrahydrofran, 1,2-dioxane, 1,3-dioxane, 1,4-dioxane, 2,2-dimethyl-1, 3-dioxolane, 2-methyl tetrahydropyran, 1,3-dioxolane, N, N-dimethyl acetamide, isopropyl isocyanate, n-propyl isocyanate, chloro methyl isocyanate, dimethyl acetal, diethyl ether, methyl isobutyl Ketone, 1,2-dimethoxyethane, 1,2-diethoxyethane, methyl formate, ethyl formate, propyl formate, methyl acetate, ethyl acetate, butyl acetate, propyl acetate, isopropyl acetate, isobutyl acetate, methyl propionate, Vinyl acetate, methyl acrylate, methyl methacrylate, glycidyl methyl ether, epoxy butane, 2-ethyl oxirane, oxazole, 2-ethyloxazole, oxazoline, 2-methyl-2-oxazoline, acetone, Methyl ethyl ketone, acetic anhydride, 1-nitropropane, 2-nitropropane, furan, γ-butyrolactone, thiophene, pyridine, 1-methyl pyrolizine, N-methyl morpholine and the like can be used.

The lithium sheet refers to a lithium original foil pre-extruded to a thickness of about 150 to 1000 um, for example. In addition, the lithium sheet means a pure lithium plate material or an alloy plate material containing lithium. A lithium foil having a thickness of 100 um or less may be formed by rolling the lithium sheet using the lithium rolling device according to an embodiment of the present invention.

The lithium sheet is supplied to the rolling unit while being wound on the reel 50 and unwound, and after being rolled, it is wound on the reel 51 disposed opposite to the direction opposite to the reel 50. A plurality of tension rolls 40A and 40B are formed in a part of the lithium rolling apparatus 100 to adjust the speed of the lithium sheet, properly control the tension, and wind the lithium sheet flatly on the reel 51. The plurality of tension rolls 40A and 40B may be simply positioned in one direction to control the tension of the lithium sheet, or arranged in a zigzag pattern on both sides of the lithium sheet to more efficiently control the tension of the lithium sheet. .

However, since lithium is a relatively soft metal compared to other metals, when the tension is controlled using only the tension rolls 40A and 40B, there is a high possibility that the lithium sheet will be torn or deformed.

In order to solve this problem, the present invention tried to control the tension applied to the lithium foil by using the conveyor device 20 in order to prevent deformation or damage of the lithium foil rolled by the rolling unit. Hereinafter, the configuration of the conveyor belt 20 and the lithium rolling method will be described in detail with reference to the drawings.

In addition, when the tension is controlled using the conveyor device 20, when tension is applied between the rolling roll and the belt provided in the conveyor device 20, the lithium foil is directly subjected to tension and plate breakage occurs, or There is a high possibility that abnormalities in surface quality will occur. In order to solve this problem, it is necessary to configure a device (hereinafter referred to as a dancer roll) that adjusts the tension between the rolling roll and the belt so that the lithium foil does not receive direct tension between the rolling roll and the conveyor device 20. It is important.

As shown in FIG. 1, by additionally configuring dancer rolls 42A, 42B, and 42C between the rolling rolls 10A and 10B and the conveyor device 20, direct tension on the lithium foil can be controlled so as not to be applied. there is. Hereinafter, since the dancer rolls 42A, 42B, and 42C are already known technologies, a detailed description thereof will be omitted.

2 and 3 are cross-sectional and top views schematically illustrating the structure of a conveyor device provided in a lithium rolling device according to an embodiment of the present invention. Here, FIG. 2 is an enlarged view of portion A of FIG. 1 , and FIG. 3 is a top view of the conveyor device shown in FIG. 2 .

Referring to FIGS. 2 and 3 , the first roll 10A in contact with the first surface of the lithium sheet 60 and the second roll 10B in contact with the second surface of the lithium sheet 60 generate lithium A sheet 60 is rolled to make a lithium foil 61. Here, the lithium sheet 60 is disposed at the rear end of the first roll 10A and the second roll 10B in order to transfer the lithium sheet 60 while controlling the tension applied to the lithium sheet 60 in contact with at least a part of the second surface. A first conveyor device 20A may be included.

As an example, the lithium rolling device 100 according to an embodiment of the present invention can control the tension applied to the lithium foil 61 with only one first conveyor device 20A. In this case, when one end of the lithium foil 61 is rolled by the first roll 10A and the second roll 10B, it can be rolled up on either side. In order to solve this problem, in the present invention, the first surface of the lithium foil 61 opposite to the first conveyor device 20A, that is, the guide roll 11 in contact with any part of the upper surface of the lithium foil 61 is further provided. include The guide roll 11 only participates in the transfer of the lithium foil 61 and maintains a constant gap so as not to affect the shape of the lithium foil 61 by being in close contact with the first conveyor device 20A.

The first conveyor device 20A includes a support 23 for supporting the lithium foil 61, a belt 25 surrounding the support 23 and in contact with the lithium foil 61, and a driving unit for driving the belt 25. can include Here, the driving unit may include a driving roll 21 and a power unit 22 capable of rotating the driving roll 21 .

In addition, the first conveyor device 20A has at least a portion of it in surface contact with the second surface of the lithium foil 61 to control the tension applied to the lithium foil 61 while the belt 25 conveys the lithium foil 61. can include

The belt 25 may be disposed to be driven along an outer circumferential surface of the driving unit, and a support 23 is formed inside the belt 25 to support the lithium foil 61 . Here, anchor units 24 are formed on both sides of the support 23 so as not to interfere with the driving of the first conveyor device 20A. The support 23 is formed to have a size substantially similar to the diameter of the driving roll 21 of the first conveyor device 20A, and may prevent the lithium foil 61 from sagging by adhering to the belt 25 .

The width of the belt 25 is greater than that of the lithium foil 61, and the lithium foil 61 is transported at the same speed as the belt 25 in a state of being in surface contact with the belt 25 by the driving force of the belt 25. It can be. If the width of the belt 25 is equal to or smaller than the width of the lithium foil 61, the tension applied to the lithium foil 61 cannot be properly controlled, and thus the lithium sticking phenomenon may not be suppressed. . Therefore, the width of the belt 25 should always be greater than that of the lithium foil 61 .

The material of the belt 25 may include, for example, a polymer material. Moreover, the same material as the belt 25 can also be used for the material of the 1st roll 10A and the 2nd roll 10B. The type of polymer material may include any one of polyethylene, polypropylene, vinylidene, polyolefin, and polyester, and in addition, any material that does not cause lithium sticking due to low adhesion to lithium may be used. do.

The lower surface of the lithium foil 61 and a part of the belt 25 come into surface contact, and the lithium foil 61 is transported along the belt 25 and finally wound around a reel 51 by the resistance generated therefrom. The reel 51 can automatically rotate by the force transferred from the conveyor device 25 without a separate driving unit.

Alternatively, in order to wind the lithium foil 61, the reel 51 may be driven by being provided with a driving unit on one side.

In addition, as described above with reference to FIG. 1, when the lithium foil 61 is directly transferred using the conveyor device 20, tension is directly applied to the lithium foil 61, which may cause quality problems. , The lithium foil 61 can be smoothly transported through the conveyor device 20 by providing the dancer rolls 42A, 42B, and 42C after the first roll 10A and the second roll 10B.

Although not shown in the figure, if the material of the first roll (10A) and the second roll (10B) is not made of a polymer, for example, when a metal material is used, the first roll (10A) and the second roll (10B) A resin film is further interposed on at least one surface of the lithium sheet 60 that comes into contact with any one of the two rolls 10B, so that rolling can be performed without sticking of the lithium sheet 60 . The resin film may include, for example, any one of polyethylene, polypropylene, vinylidene, polyolefin, and polyester.

Meanwhile, in the lithium rolling device 100 according to an embodiment of the present invention, a conveyor device may be additionally applied instead of the guide roll 11. A detailed description of this will be described later with reference to the drawings.

4 and 5 are cross-sectional views schematically illustrating the structure of a lithium rolling device according to another embodiment of the present invention.

Referring to FIG. 4, in the lithium rolling device 100, a second conveyor device 20B is installed on the first conveyor device 20A instead of the guide roll 11 in order to more effectively control the tension of the lithium foil 61. can be formed

The structure of the second conveyor device 20B may be configured in the same form as that of the first conveyor device 20A. However, since the belt 25 of the second conveyor device 20B can uniformly apply a load to the entire upper surface of the lithium foil 61 by gravity, the support 23 provided in the first conveyor device 20A ) can be omitted.

The driving speeds of the first conveyor device 20A and the second conveyor device 20B should be the same, and should be controlled equal to or faster than the driving speeds of the first roll 10A and the second roll 10B. Here, when the size of any one of the first roll 10A and the second roll 10B is different, accordingly, the driving speeds of the first conveyor device 20A and the second conveyor device 20B are appropriately controlled. can

Referring to FIG. 5, the lithium rolling device 100 is configured to control the tension of the lithium sheet 60 as well as the tension of the lithium foil 61. and a third conveyor device 20C having a structure. Here, only the third conveyor device 20C can control the tension of the lithium sheet 60, but in order to more efficiently control the tension of the lithium sheet, a fourth conveyor having the same structure as the second conveyor device 20B The device 20D can be placed on the third conveyor device 20C. Structures of the third conveyor device 20C and the fourth conveyor device 20D are the same as those of the first conveyor device 20A and the second conveyor device 20B, respectively, so detailed descriptions thereof are omitted.

The driving speeds of the third conveyor device 20C and the fourth conveyor device 20D must be the same. At this time, the driving speed of the third conveyor device 20C should be controlled equal to or slower than the driving speed of the first conveyor device 20A provided at the rear end of the first roll 10A and the second roll 10B. . That is, the drive speeds of the third conveyor device 20C, the rolling section (the first roll 10A and the second roll 10B), and the first conveyor device 20A must all be equally controlled. Alternatively, the driving speed of the third conveyor device 20A should be controlled slower than the driving speed of the first conveyor device 20A. Further, the drive speed of the third conveyor device 20A must be controlled relatively slower than the drive speed of the rolling section (first roll 10A and second roll 10B).

Although the present invention has been described with reference to the embodiments shown in the drawings, this is merely exemplary, and those skilled in the art will understand that various modifications and equivalent other embodiments are possible therefrom. Therefore, the true technical protection scope of the present invention should be determined by the technical spirit of the appended claims.

10A: first roll
10B: second roll
11: guide roll
20: conveyor device
21: drive roll
22: power unit
23: support
24: anchor part
25: Belt
30: lubricant supply unit
40A, 40B: tension roll
42A, 42B, 42C: dancer rolls
50, 51: reel
60: lithium sheet
61: lithium foil
100: lithium rolling device

Claims (19)

An apparatus for forming a lithium foil by rolling a lithium sheet,
a first roll contacting the first surface of the lithium sheet;
a second roll contacting the second surface of the lithium sheet; and
A belt disposed at rear ends of the first roll and the second roll and having at least a portion of the belt in surface contact with the second surface of the lithium foil to control tension applied to the lithium foil and transport the lithium foil. 1 conveyor device; including,
Lithium rolling device. According to claim 1,
The first conveyor device further comprises a support for supporting the lithium foil and a driving unit for driving the belt.
Lithium rolling device. According to claim 1,
When the lithium foil is conveyed by the first conveyor device, a guide roll formed at a portion in contact with the first surface of the lithium foil on the first conveyor device so that the lithium foil can be conveyed flatly.
Lithium rolling device. According to claim 1,
A second conveyor device disposed above the first conveyor device and contacting the first surface of the lithium foil to transfer the lithium foil,
Lithium rolling device. According to claim 4,
The first conveyor device and the second conveyor device are driven at the same speed,
Lithium rolling device. According to claim 1,
A third conveyor device disposed at front ends of the first roll and the second roll to transfer the lithium sheet in contact with at least a portion of the second surface of the lithium sheet,
Lithium rolling device. According to claim 6,
The driving speed of the third conveyor device is controlled to be equal to or slower than the driving speed of the first conveyor device.
Lithium rolling device. According to claim 6,
A fourth conveyor device disposed above the third conveyor device and contacting the first surface of the lithium sheet to transport the lithium sheet,
Lithium rolling device. According to claim 6,
The third conveyor device and the fourth conveyor device are driven at the same speed,
Lithium rolling device. According to claim 6,
The driving speed of the third conveyor device is controlled equal to or slower than the driving speed of the first roll and the second roll,
Lithium rolling device. According to claim 1,
In order to suppress a sticking phenomenon, including a lubricant supply unit for spraying a lubricant on at least one surface of the lithium sheet before being rolled by the first roll and the second roll,
Lithium rolling device. According to claim 1,
The first roll, the second roll and the belt include a polymer material,
Lithium rolling device. According to claim 12,
The polymer material includes any one of polyethylene, polypropylene, vinylidene, polyolefin and polyester,
Lithium rolling device. According to claim 1,
A resin film is further interposed on at least one side of the lithium sheet that comes into contact with either the first roll or the second roll to suppress a sticking phenomenon of the lithium sheet,
Lithium rolling device. According to claim 1,
The width of the belt of the first conveyor device is greater than the width of the lithium foil,
The lithium foil is transported at the same speed as the belt in a state of surface contact with the belt by the driving force of the belt.
Lithium rolling device. According to claim 1,
The driving speed of the first conveyor device is controlled equal to or faster than the driving speed of the first roll and the second roll,
Lithium rolling device. forming a lithium foil by rolling using a first roll in contact with the first surface of the lithium sheet and a second roll in contact with the second surface of the lithium sheet; and
A belt provided on the first conveyor device is in surface contact with at least a portion of the second surface of the lithium foil by a first conveyor device disposed at rear ends of the first roll and the second roll, so that the lithium foil is caught. Transferring while controlling the tension; Including,
Lithium rolling method. 18. The method of claim 17,
Tension applied to the lithium foil when the lithium foil is transported by the first conveyor device by a guide roll formed on a portion of the first conveyor device that contacts the first surface of the lithium foil or a second conveyor device is controlled, and the lithium foil is conveyed flat,
Lithium rolling method. 18. The method of claim 17,
The driving speed of the first conveyor device is controlled equal to or faster than the driving speed of the first roll and the second roll,
Lithium rolling method.

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