Raw copper material with improved melting rate

Abstract

One embodiment of the present invention provides a raw copper material comprising an iron (Fe) element in the range of 5 to 1000 ppm. The iron (Fe) element is measured using an inductively coupled plasma (ICP) analysis method.

Description

Copper raw materials with improved dissolution rate

[0001] The present invention relates to a copper raw material for manufacturing copper foil used in manufacturing various products such as anodes for secondary batteries and flexible printed circuit boards.

[0002] Copper foil is used to manufacture a variety of products, including secondary battery cathodes and flexible printed circuit boards (FPCBs). This copper foil is manufactured through electroplating, which involves supplying an electrolyte between the anode and cathode and then passing a current through it. Copper foil manufacturing equipment is used to manufacture copper foil through this electroplating process.

[0003] The above copper foil manufacturing device manufactures copper foil by electroplating using a plating solution formed by dissolving copper raw materials. Here, if the copper foil manufacturing device has a slow dissolution rate for dissolving the copper raw materials compared to the manufacturing speed (plating rate) of the copper foil, the productivity of the copper foil decreases.

[0004] Therefore, in order to increase the productivity of copper foil, the development of copper raw materials that can improve the melting speed is required.

[0005] The present invention has been devised to solve the above-described needs, and to provide a copper raw material that can prevent the productivity of copper foil from decreasing due to the dissolution rate.

[0006] One embodiment of the present invention provides a raw material comprising iron (Fe) element in a range of 5 to 1000 ppm. The iron (Fe) element is measured using an inductively coupled plasma (ICP) analysis method.

[0007] One embodiment of the present invention provides a copper sulfate solution manufactured using the above raw material.

[0008] One embodiment of the present invention provides a copper foil manufactured using the above raw material.

[0009] One embodiment of the present invention provides a negative electrode plate for a lithium secondary battery manufactured using the above raw material.

[0010] One embodiment of the present invention provides a lithium secondary battery manufactured using the above raw material.

[0011] According to the present invention, the dissolution rate can be improved by securing the fluidity of the solution, the contact time with the solution, the reaction area with the solution, etc. Therefore, the present invention can contribute to increasing the productivity of copper foil.

[0012] Figure 1 is a schematic diagram of the raw materials according to the present invention.

[0013] Figure 2 is a schematic cross-sectional view for explaining the major and minor axes of the raw material according to the present invention.

[0014] Figure 3 is a schematic cross-sectional view for explaining the thickness of the raw material according to the present invention.

[0015] Hereinafter, embodiments of the present invention will be described in detail with reference to the attached drawings. However, the embodiments described below are presented for illustrative purposes only to facilitate a clear understanding of the present invention and do not limit the scope of the present invention.

[0016] The shapes, sizes, ratios, angles, numbers, etc. disclosed in the drawings for explaining embodiments of the present invention are merely illustrative, and the present invention is not limited to the details depicted in the drawings. Throughout the specification, identical components may be designated by identical reference numerals. In describing the present invention, detailed descriptions of related known technologies will be omitted if they are deemed to unnecessarily obscure the gist of the present invention.

[0017] In this specification, where "includes," "has," and "consists of" are used, other parts may be added, unless the expression "only" is used. When a component is expressed in the singular, the plural is included unless otherwise explicitly stated. Furthermore, when interpreting a component, it is interpreted to include a margin of error even if there is no explicit indication otherwise.

[0018] When describing a positional relationship, for example, when the positional relationship between two parts is described as 'on top of', 'upper part of', 'lower part of', 'next to', etc., one or more other parts may be located between the two parts, unless the expression 'right' or 'directly' is used.

[0019] Spatially relative terms such as "below," "beneath," "lower," "above," and "upper" can be used to easily describe the relationship of one element or component to another, as illustrated in the drawings. Spatially relative terms should be understood to include different orientations of the elements during use or operation in addition to the orientations depicted in the drawings. For example, if an element depicted in the drawings were flipped over, an element described as "below" or "beneath" another element could instead be positioned "above" the other element. Thus, the exemplary term "below" can encompass both the above and below directions. Similarly, the exemplary term "above" or "above" can encompass both the above and below directions.

[0020] When describing a temporal relationship, for example, when the temporal relationship is described as 'after', 'following', 'next to', 'before', etc., it can also include cases where it is not continuous, as long as the expression 'immediately' or 'directly' is not used.

[0021] While terms like "first" and "second" are used to describe various components, these components are not limited by these terms. These terms are used merely to distinguish one component from another. Therefore, a "first" component referred to below may also be a "second" component within the technical scope of the present invention.

[0022] The term "at least one" should be understood to include all possible combinations of one or more associated items. For example, "at least one of the first, second, and third items" can mean not only the first, second, or third items, but also any combination of items that can be represented by two or more of the first, second, and third items.

[0023] The features of each of the various embodiments of the present invention can be partially or wholly combined or combined with each other, and various technical connections and operations are possible, and each embodiment can be implemented independently of each other or implemented together in a related relationship.

[0024] The copper raw material (10) according to the present invention is used to manufacture copper foil used in manufacturing various products such as anodes for secondary batteries and flexible printed circuit boards (FPCB). The copper raw material (10) according to the present invention is produced as a plating solution through melting, and then supplied to a copper foil manufacturing device, and then can be manufactured into copper foil through an electroplating method by the copper foil manufacturing device.

[0025] According to the present invention, the raw material (10) can be produced as a plating solution by being dissolved by a high-temperature dissolving solution supplied to a dissolving tank (not shown) while being loaded into a plurality of the dissolving tanks. An electrolyte solution can be used as the dissolving solution. For example, the dissolving solution can be a sulfuric acid solution.

[0026] In this case, if the dissolved solution does not flow smoothly between the raw materials (10) according to the present invention, the raw materials (10) according to the present invention placed at the lower part of the dissolution tank cannot be smoothly dissolved, and thus the dissolution rate may be slowed down. For example, if the porosity of the raw materials (10) according to the present invention loaded into the dissolution tank is too small, the raw materials (10) according to the present invention placed at the lower part of the dissolution tank cannot be smoothly dissolved, and thus the dissolution rate may be slowed down.

[0027] On the other hand, if the solution flows too quickly through the raw material (10) according to the present invention, the contact time and reaction area between the raw material (10) according to the present invention and the solution are reduced, so that the dissolution rate may slow down. For example, if the porosity of the raw material (10) according to the present invention loaded into the dissolution tank is too large, the contact time and reaction area between the raw material (10) according to the present invention and the solution are reduced, so that the dissolution rate may slow down.

[0028] Taking this into consideration, the raw material (10) according to the present invention can be implemented so as to secure the fluidity of the solution, the contact time with the solution, the reaction area with the solution, etc.

[0029] Referring to FIGS. 1 to 3, according to one embodiment of the present invention, the copper raw material (10) may have a long axis (11) ranging from 10 to 120 mm. Through this, the copper raw material (10) according to the present invention can improve the dissolution rate, thereby contributing to increasing the productivity of copper foil.

[0030] If the major axis (11) of the raw material (10) is less than 10 mm, the porosity of the raw material (10) becomes very small, so that the raw material (10) according to the present invention placed at the bottom of the melting tank cannot be smoothly melted, and thus the melting speed may be slow.

[0031] On the other hand, if the major axis (11) of the raw material (10) exceeds 120 mm, the porosity of the raw material (10) becomes very large, and the contact time and reaction area between the raw material (10) and the solution are reduced, so the dissolution rate may become slow.

[0032] According to one embodiment of the present invention, the copper raw material (10) may have a short axis (12) in the range of 4 to 50 mm. Through this, the copper raw material (10) according to the present invention can improve the dissolution rate, thereby contributing to increasing the productivity of copper foil.

[0033] If the short axis (12) of the raw material (10) is less than 4 mm, the porosity of the raw material (10) becomes very small, so that the raw material (10) according to the present invention placed at the bottom of the melting tank cannot be smoothly melted, and thus the melting speed may be slow.

[0034] On the other hand, if the short axis (12) of the raw material (10) exceeds 50 mm, the porosity of the raw material (10) becomes very large, and the contact time and reaction area between the raw material (10) and the solution are reduced, so the dissolution rate may become slow.

[0035] According to one embodiment of the present invention, the copper raw material (10) may have a thickness (13) in the range of 2 to 8 mm. Through this, the copper raw material (10) according to the present invention can improve the dissolution rate, thereby contributing to increasing the productivity of copper foil.

[0036] If the thickness (13) of the raw material (10) is less than 2 mm, the porosity of the raw material (10) becomes very small, so that the raw material (10) according to the present invention placed at the bottom of the melting tank cannot be smoothly melted, and thus the melting speed may be slow.

[0037] On the other hand, when the thickness (13) of the raw material (10) exceeds 8 mm, the porosity of the raw material (10) becomes very large, and the contact time and reaction area between the raw material (10) and the solution are reduced, so the dissolution rate may become slow.

[0038] Here, the major axis (11), minor axis (12), and thickness (13) can be measured according to the following measurement criteria. The major axis (11), minor axis (12), and thickness (13) can be measured using a CD-APX of Mitutoyo vernier caliper.

[0039] Referring to FIGS. 2 and 3, the major axis (11) may be the length of two points spaced apart by the maximum straight-line distance based on the measurement plane (MP). The measurement plane (MP) may be determined as any one of the planes within a range of ±20° angles from the candidate plane after selecting a candidate plane perpendicular to the direction in which the major axis (11) is most widely projected. Once the major axis (11) is determined, an imaginary line connecting the two points that serve as the reference for the major axis (11) may be determined in the major axis direction (LD axis direction).

[0040] Referring to FIGS. 2 and 3, the short axis (12) may be the length of two points spaced apart by the minimum straight-line distance based on the short axis direction (SD axis direction). The short axis direction (SD axis direction) may be an axial direction perpendicular to the long axis direction (LD axis direction). When the length of the long axis (11) is N (N is a real number greater than 0), the short axis (12) may be the length of two points spaced apart by the minimum straight-line distance based on the short axis direction (SD axis direction) in an effective portion (11a) that is 0.3 N or more and 0.7 N or less based on the long axis direction (LD axis direction).

[0041] Accordingly, the portion that is less than 0.3 N and the portion that is more than 0.7 N based on the long axis direction (LD axis direction) can be excluded from the measurement target of the short axis (12). This is in consideration of the fact that the ends on both sides are often formed too short or too long, and although a sufficient dissolution rate can be secured through this, the amount excluded due to the ends on both sides can be reduced. Therefore, the raw material (10) according to the present invention can contribute to lowering the manufacturing cost of copper foil by reducing the amount of waste while ensuring a sufficient dissolution rate.

[0042] Referring to FIGS. 2 and 3, the thickness (13) may be a length based on the thickness direction (TD axis direction). The thickness direction (TD axis direction) may be an axial direction perpendicular to each of the major axis direction (LD axis direction) and the minor axis direction (SD axis direction). The thickness (13) may be an average value of thickness values ​​measured M times (M is a natural number) in the thickness direction (TD axis direction).

[0043] This partially takes into account the fact that there is a large variation in thickness, and through this, even though a sufficient dissolution rate can be secured, the amount excluded due to partial thickness variation can be reduced. Therefore, the raw material (10) according to the present invention can contribute to lowering the manufacturing cost of copper foil by reducing the amount of waste even though a sufficient dissolution rate can be secured. For example, M may be 5, and in this case, the thickness (13) may be the average value of the thickness values ​​measured at five different parts.

[0044] According to one embodiment of the present invention, the raw material (10) may include iron (Fe) element in the range of 5 to 1000 ppm.

[0045] According to one embodiment of the present invention, the iron (Fe) element of the raw material (10) is measured through an ICP (Inductively Coupled Plasma) analysis method.

[0046] When the iron (Fe) element concentration of the raw material (10) is less than 5 ppm, the iron (Fe) element is unevenly deposited on the anode in the form of iron sulfate (FeSO4), and current unevenness occurs due to the uneven electrodeposition layer, and as a result, the weight of the copper foil plated on the cathode becomes uneven in the width direction, resulting in a weight deviation.

[0047] When the concentration of iron (Fe) element in the raw material (10) exceeds 1000 ppm, the iron (Fe) element affects the concentration analysis of copper (Cu) element. Specifically, the concentration of copper (Cu) element is one of the standards strictly managed in the production of electrolytic copper foil, and when the concentration of iron (Fe) element in the raw material (10) exceeds 1000 ppm, it may be difficult to measure the concentration of copper (Cu) element. In addition, since iron (Fe) is preferentially oxidized over copper (Cu), when the concentration of iron (Fe) element is excessively excessive, a problem may occur in which the dissolution rate is reduced due to the excessively included iron (Fe) element.

[0048] According to one embodiment of the present invention, the raw material (10) may include lead (Pb) element in the range of 5 to 200 ppm.

[0049] On the other hand, when the concentration of lead (Pb) element of the raw material (10) exceeds 200 ppm, the lead (Pb) element is precipitated as lead sulfate (PbSO4) and deposited inside the plating tank where plating is performed. The plating tank has a part that functions as an anode at the bottom and a part that functions as a cathode at the top. Copper sulfate solution is supplied to the plating tank between the anode and the cathode, and the lead sulfate (PbSO4) deposited in this space affects the flow of the copper sulfate solution and at the same time causes current unevenness, so that the weight of the copper foil plated on the cathode is not uniform in the width direction, resulting in a weight deviation.

[0050] On the other hand, when the concentration of lead (Pb) element in the raw material (10) is less than 5 ppm, the lead (Pb) element is unevenly deposited on the anode in the form of lead sulfate (PbSO4), and current unevenness occurs due to the uneven electrodeposition layer, and as a result, the weight of the copper foil plated on the cathode becomes uneven in the width direction, resulting in a weight deviation.

[0051] According to one embodiment of the present invention, the raw material (10) may contain 40 ppm or less of silver (Ag) element.

[0052] On the other hand, if the concentration of silver (Ag) element in the raw material (10) exceeds 40 ppm, when winding the copper foil, a dent may be formed in the copper foil that is wound in a roll shape, and permanent deformation of the copper foil may occur due to the high winding tension and weight.

[0053] Meanwhile, the raw material (10) according to the present invention has a purity of 99% or more and can be formed without oil. The raw material (10) according to the present invention can be implemented as waste wire or can be implemented by cutting waste wire according to standard conditions.

[0054] According to one embodiment of the present invention, the raw material (10) may be a single crystal and may have an anisotropic structure. That is, the raw material (10) according to the present invention may be implemented as an anisotropic raw material. In this case, rather than being manufactured to have a certain shape by a manufacturing device (not shown), an anisotropic raw material that satisfies the above-described standard conditions among those manufactured by the manufacturing device may correspond to the raw material (10) according to the present invention, and the dissolution rate may be improved through the anisotropic shape.

[0055] For example, the copper raw material (10) according to the present invention can be produced by processing low-purity copper containing impurities into a high-purity copper melt through a dry refining process and then cooling the high-purity copper melt using a granulator. In this case, among the anisotropic raw materials formed by the granulator, those that satisfy the above-described standard conditions can correspond to the copper raw material (10) according to the present invention. Meanwhile, the granulator can be implemented to form the anisotropic raw material using water. Accordingly, the copper raw material (10) according to the present invention can be formed without oil without a separate pretreatment. Figure 1 shows a photograph of four copper raw materials (10) according to the present invention produced by the granulator.

[0056] Meanwhile, a copper sulfate solution according to the present invention can be produced using the raw material (10) according to the present invention as described above. The copper sulfate solution according to the present invention can be used as a plating solution in producing copper foil.

[0057] Meanwhile, a copper foil according to the present invention can be manufactured using the raw material (10) according to the present invention as described above.

[0058] Meanwhile, a negative electrode plate for a lithium secondary battery according to the present invention can be manufactured using the raw material (10) according to the present invention as described above.

[0059] Meanwhile, a lithium secondary battery according to the present invention can be manufactured using the raw material (10) according to the present invention as described above.

[0060] Below, the manufacturing method of the raw material (10) of the present invention is specifically described.

[0061] The copper raw material (10) can be manufactured by a manufacturing method including a melting step and a cooling step. Specifically, copper that has gone through the melting step passes through a perforated plate having a certain diameter of a manufacturing device (not shown), and the molten liquid that has passed through the perforated plate passes through a cooling step to form the copper raw material.

[0062] At this time, the perforation plate reciprocates left and right from the inlet, repeatedly closing and opening the perforated surface. Specifically, the copper molten liquid falls freely the moment the perforation plate opens, and the appropriate perforation plate opening time can be adjusted by adjusting the reciprocating movement speed of the perforation plate.

[0063] In the above melting step, copper melted at 1130°C or higher, preferably 1130 to 1200°C, is sprayed and supplied as a solution through a nozzle.

[0064] Here, when the temperature is lower than 1130℃ during copper melting, there is a problem in that the copper is not melted sufficiently, and the solution is not sufficiently sprayed and supplied through the nozzle.

[0065] On the other hand, when the temperature exceeds 1200℃ during copper melting, there is a problem in that the molten copper is formed into a copper raw material with an excessively coarse shape.

[0066] In the above cooling step, the molten copper can be cooled using cooling water. The cooling water inlet temperature is 18 to 20°C, and the cooling water inlet-outlet temperature difference, which is the difference between the cooling water outlet temperature and the cooling water inlet temperature, is 2°C or less.

[0067] At this time, the coolant inlet temperature means the temperature of the coolant inlet pipe, and the coolant outlet temperature means the temperature of the coolant outlet pipe.

[0068] Here, when the coolant inlet temperature is less than 18℃, there is a problem in that the coolant inlet temperature is very low and the molten copper is formed into excessively fine copper raw material.

[0069] On the other hand, if the coolant inlet temperature exceeds 20℃, there is a problem in that the coolant inlet temperature is very high and the molten copper is formed into an excessively coarse copper raw material.

[0070] In addition, when the difference in temperature between the coolant inlet and outlet exceeds 2℃, the difference in temperature between the coolant inlet and outlet is very large, and the size difference between the copper raw materials generated in the area with a relatively high temperature and the copper raw materials generated in the area with a relatively low temperature is very large, so there is a problem in that the copper raw materials are formed to be excessively fine or excessively coarse.

[0071] The size of the raw material can be adjusted by controlling the opening time of the punching plate, and the punching plate has an opening time of 0.1 to 0.4 seconds.

[0072] When the opening time of the perforation plate is less than 0.1 second, the opening time of the perforation plate is so short that the molten copper does not sufficiently come out of the perforation plate, and as a result, there is a problem in that the molten copper is formed into excessively fine copper raw material.

[0073] On the other hand, if the opening time of the perforation plate exceeds 0.4 seconds, the opening time of the perforation plate is very long, so there is a problem that excessive molten copper comes out of the perforation plate, and as a result, there is a problem that the molten copper is formed into an excessively coarse copper raw material.

[0074] The raw material of the present invention can be manufactured by the above method.

[0075] Below, the present invention is specifically described through examples and comparative examples. However, the following examples are provided solely to aid understanding of the present invention, and the scope of the present invention is not limited to these examples.

[0076] Example 1-3 and Comparative Example 1-6

[0077] By controlling the copper melting temperature, cooling water inlet temperature, cooling water outlet temperature, cooling water inlet / outlet temperature difference, porous opening time, and perforation diameter of the copper plate as described in Table 2 below using a manufacturing device (not shown), copper raw materials corresponding to Examples 1 to 3 and Comparative Examples 1 to 6 having the characteristics described in Table 1 were manufactured.

[0078] Classification standard Iron (Fe) (ppm) Lead (Pb) (ppm) Silver (Ag) (ppm) Weight deviation (mg / 25cm) 2 ) Number of appearance defects (number) Dissolution rate (g / L·hr) Long axis (mm) Short axis (mm) Thickness (mm) Example 155 255.12 50 180 70.32 0.5 4.31 Example 240 154.31 20 116 250.22 0.23.28 Example 360 ​​336.86 5420.20.7 4.30 Comparative example 160 20 11.51 200 120 90.18 0.52 .25Comparative Example 2806012.81156115100.210.41.78Comparative Example 3854.9113580150.230.51.76Comparative Example 4953.4105976180.300.81.75Comparative Example 5150255.0130087740.172.11.77Comparative Example 6140204.51230250223.510.61.78

[0079] When melting copper, the temperature of the cooling water inlet temperature, the temperature of the cooling water outlet temperature, the temperature difference between the cooling water inlet and outlet, and the time of the punching hole opening are all different. DiameterExample 1115118.219.41.20.225Example 2113819.419.80.40.225Example 3114519.119.60.50.225Comparative Example 1113719.522.63.10.225Comparative Example 2114222.422.90.50.225Comparative Example 3110818.819.40.60.225Comparative Example 4114516.517.20.70.225Comparative Example 5115118.219.41.20.525Comparative Example 6114518.819.41.00.625

[0080] For the raw materials of Example 1-5 and Comparative Example 1-6 manufactured in this manner, i) specifications for major and minor axis thickness, ii) concentrations of iron (Fe), lead (Pb), and silver (Ag), iii) weight deviation, iv) number of appearance defects, and v) dissolution rate were confirmed.

[0081] i) Specifications for long axis, short axis and thickness

[0082] The raw material has multiple particles, and the long axis, short axis and thickness refer to the long axis, short axis and thickness of the particles.

[0083] The major axis is the length of two points separated by the greatest straight-line distance based on the measuring plane (MP) of the same raw material.

[0084] Short axis is the length of two points separated by the shortest straight-line distance based on the short axis direction (SD axis direction).

[0085] The thickness corresponds to the average value of the thickness of the raw materials corresponding to the range of the long axis and the range of the short axis in each of the examples and comparative examples.

[0086] The major axis, minor axis, and thickness were measured using the CD-APX of Mitutoyo vernier calipers.

[0087] ii) Measurement of concentrations of iron (Fe), lead (Pb), and silver (Ag)

[0088] The concentrations of iron (Fe), lead (Pb), and silver (Ag) contained in the raw materials are measured using the ICP (Inductively Coupled Plasma) analysis method.

[0089] iii) Weight deviation

[0090] Weight deviation refers to the weight deviation of copper foil manufactured using the same raw material. Specifically, the plated and rolled copper foil is cut in the width direction and the thickness is measured in the width direction by X-ray. Then, among the thicknesses measured along the width direction, the maximum and minimum values ​​are selected at three points each, and the weight is measured by cutting a 5 cm x 5 cm piece centered on the selected points and calculating the standard deviation. In this case, if the weight deviation exceeds 3%, the physical property deviation occurs on the surface of the copper foil, which increases the number of wrinkles and causes the physical properties of the current collector to become uneven, and thus it is treated as a defect.

[0091] iv) Number of appearance defects

[0092] The number of appearance defects refers to the number of appearance defects in copper foil manufactured using the same raw material. If the number of appearance defects exceeds 2, the copper foil surface characteristics become uneven. Here, the number of appearance defects was measured by cutting the copper foil manufactured using the same raw material into samples with a width of 1300 mm and a length of 10 km, and detecting the number of appearance defects detected on the surface of the sample by AOI (Automated Optical Inspection).

[0093] v) Dissolution rate

[0094] The dissolution rate in Table 1 above corresponds to the average value of the dissolution rate of the raw materials (10) corresponding to the standard conditions of each of the examples and comparative examples.

[0095] The dissolution rate in Table 1 above was measured using a measuring device having a dissolution tank, a storage tank, a circulation pump, a cooling line, and an air blower.

[0096] In the above measuring equipment, the dissolution tank is for accommodating the raw material, and can be implemented so that the solution is sprayed and supplied to the dissolution tank of the measuring equipment through the upper nozzle.

[0097] In the above measuring equipment, the storage tank can be implemented so that the solution that has come into contact with the raw material in the dissolution tank is collected in the lower tank, and the collected solution is supplied back to the dissolution tank through the circulation pump.

[0098] In the above measuring equipment, the cooling line is for re-condensing moisture evaporated from the solution, and can be implemented so that cooling water flows in a counter-flow manner in the exhaust pipe of the storage tank.

[0099] In the above measuring equipment, an air blower can be implemented to supply air to the melting tank to assist the oxidation reaction of copper.

[0100] Using the measuring equipment implemented in this way, a copper sulfate solution was produced under the following experimental conditions: a sulfuric acid solution prepared by adding 12 kg of sulfuric acid (95%) to 40 L of pure water (DI water); a liquid temperature maintained at 50°C; a circulation flow rate of 25 L / min by the circulation pump; an air supply rate of 50 to 90 L / min by the air blower; a cooling water temperature of 4°C by the cooling line; a cooling water flow rate of 5 L / min by the cooling line; and an input amount of 13 kg of the raw material. In this case, the sulfuric acid solution may correspond to the dissolution solution, and the copper sulfate solution may correspond to the plating solution. By operating the measuring equipment for 24 hours under the corresponding experimental conditions and measuring the concentration of the produced copper sulfate solution, the dissolution rate in Table 1 was derived in units of g / L·hr.

[0101] As can be seen from Table 1 above, when the temperature difference between the coolant inlet and outlet exceeds 2℃ (Comparative Example 1), the thickness of the manufactured raw material becomes excessively large, and the melting speed does not occur smoothly.

[0102] When the cooling water inlet temperature is excessively high (Comparative Example 2), the shortening and thickness of the manufactured raw material become excessively large, and the melting speed does not occur smoothly.

[0103] When the temperature is excessively low during copper melting (Comparative Example 3), the major axis of the manufactured copper raw material is excessively small, so the melting speed does not occur smoothly.

[0104] When the cooling water inlet temperature is excessively low (Comparative Example 4), the major axis of the manufactured raw material is excessively small, so the melting speed does not occur smoothly.

[0105] When the opening time of the punching plate is excessively long (Comparative Example 5), the major axes of the manufactured copper raw material become excessively large, so that the melting speed is not smooth, and when it contains an excessive amount of silver (Ag) (Comparative Example 5), the number of appearance defects in the copper foil manufactured from the copper raw material increases.

[0106] When the opening time of the punching plate is excessively long (Comparative Example 6), the major axes of the manufactured copper raw material become excessively large, so that the melting speed is not smooth, and when lead (Pb) is included excessively (Comparative Example 6), a weight deviation occurs in the copper foil manufactured from the copper raw material.

[0107] The present invention described above is not limited to the aforementioned embodiments and the attached drawings, and it will be apparent to those skilled in the art that various substitutions, modifications, and changes are possible without departing from the technical scope of the present invention. Therefore, the scope of the present invention is expressed by the following claims, and all changes or modifications derived from the meaning, scope, and equivalent concepts of the claims should be interpreted as being included within the scope of the present invention.

Claims

A raw material containing iron (Fe) element in the range of 1.5 to 1000 ppm: The above iron (Fe) element is measured using the ICP (Inductively Coupled Plasma) analysis method.

2. In paragraph 1, A raw material containing lead (Pb) element in the range of 5 to 200 ppm.

3. In paragraph 1, Copper raw material containing less than 40 ppm of silver (Ag) element.

4. In paragraph 1, Long axis ranging from 10 mm to 120 mm; Shortening in the range of 4 mm to 50 mm; and A raw material having a thickness ranging from 2 mm to 8 mm.

5. In paragraph 1, A raw material that is single crystal and has an anisotropic structure.

6. In paragraph 4, The above major axis is the length of two points separated by the maximum straight-line distance based on the measurement plane, The above-mentioned shortened axis is the length of two points separated by the minimum straight-line distance based on the short-axis direction perpendicular to the long-axis direction connecting the two points that serve as the reference of the long axis. The above thickness is a length based on the thickness direction perpendicular to the long axis direction and the short axis direction, respectively.

7. In paragraph 6, When the length of the major axis is L (L is a real number greater than 0), the minor axis is the length of two points spaced apart by the minimum straight-line distance based on the minor axis direction in an effective portion that is 0.3L or more and 0.7L or less based on the major axis direction.

8. In paragraph 6, The above thickness is the average value of the thickness values ​​measured M times (M is a natural number) in the above thickness direction, the same raw material.

9. In paragraph 1, A copper raw material characterized by having a purity of 99% or more and being free of oil.

10. A copper sulfate solution manufactured using any one of the raw materials in clauses 1 to 9.

11. Copper foil manufactured using any one of the raw materials in clauses 1 to 9.

12. A negative electrode plate for a lithium secondary battery manufactured using any one of the raw materials of clauses 1 to 9.

13. A lithium secondary battery manufactured using any one of the raw materials of clauses 1 to 9.

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