A matte electrolytic copper foil and a method for producing the same

Abstract

The application discloses a matte electrolytic copper foil and a preparation method thereof. The copper foil obtained through the preparation method has a matte surface with moderate brightness, is consistent with the appearance of a bright surface, has good flexibility, low warping, a roughness Rz of less than 1.0 microns, a high-temperature tensile strength of more than 450 MPa, an elongation of more than 6.0%, and reduced edge tearing in a foil forming process, thereby effectively improving the yield of finished products, and the production control process is simple and the cost is low.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of lithium ion battery copper foil, and particularly relates to a matte electrolytic copper foil and a preparation method thereof. BACKGROUND

[0002] Lithium ion batteries have the advantages of high mass specific energy, high working voltage, long cycle life, environmental friendliness, etc., and are widely used in new energy vehicles, energy storage facilities, consumer electronics and other fields. As one of the most mature commercial secondary energy sources at present, electrolytic copper foil, as the carrier of the negative electrode current collector and active material of lithium ion batteries, has greatly developed in recent years due to strong market demand.

[0003] The traditional copper foil for lithium ion batteries is double-sided bright copper foil, and the process is derived from the full bright acid copper plating MN system. The process has the disadvantages of excessive grain refinement, high internal stress, room temperature self-annealing, product rough surface brightness much greater than the smooth surface, easy warping, etc. In the production process, the proportion and concentration of additives are usually adjusted to control the gloss and reduce warping, but problems such as bulging, thickness increase, and inconsistent roughness often occur, resulting in low yield and poor quality. SUMMARY

[0004] The purpose of the present application is to overcome the shortcomings and deficiencies of the prior art and provide a matte electrolytic copper foil and a preparation method thereof.

[0005] The technical scheme adopted by the present application is as follows: a preparation method of a matte electrolytic copper foil, characterized by comprising the following steps:

[0006] (1) Clean cathode copper plates or copper wires are placed in a copper dissolving tank in a staggered manner, low-copper high-acid electrolyte is pumped in, and compressed air is blown into the bottom of the tank to obtain high-copper low-acid electrolyte;

[0007] (2) The electrolyte passes through the electrolyte tank of the foil machine, and high-copper low-acid electrolyte is added according to the measured concentration and flows into the contaminated liquid tank, and powdered activated carbon is added quantitatively, which passes through a diatomaceous earth filter and a precision filter in sequence and flows into the clean liquid tank;

[0008] (3) The additive solution is added to the clean liquid tank by a metering pump according to the measured amount, and is uniformly stirred to obtain clean electrolyte, and the concentrations of the additives are as follows: brightener 0.8-3.0 mg / L, walking agent 2.0-12.0 mg / L, grain control agent 0.5-5.0 mg / L, and chloride ion 20-50 mg / L;

[0009] (4) The clean electrolyte is pumped by a clean liquid pump to the high tank, and flows into the foil machine at a constant flow rate to perform power-on roll plating and foil stripping, and the copper foil semi-finished product is peeled off at a controlled roll rotation linear speed, and the electrolyte flows back to the copper dissolving tank and the contaminated liquid tank;

[0010] (5) the copper foil semi-finished product is subjected to pickling, water washing, anti-oxidation treatment, baking, rolling, slitting and packaging to obtain a copper foil finished product.

[0011] Preferably, in step (3), the brightener is sodium polydithiodipropyl sulfone, the running agent is compound hydrolyzed gelatin, and the grain control agent is glucose and polyglycerol.

[0012] Preferably, the compound hydrolyzed gelatin is obtained by compounding low molecules with a molecular weight of 3000-5000 and high molecules with a molecular weight of 15000-25000 at a ratio of 1:0.8-1.2.

[0013] Preferably, the ratio of glucose and polyglycerol is 1:1.

[0014] A matte electrolytic copper foil obtained by the preparation method has a roughness Rz of less than 1.0 μm, a high-temperature tensile strength of more than 450 MPa, and an elongation of more than 6.0%.

[0015] The present application provides a preparation method of a matte electrolytic copper foil, which uses a plurality of additives to compound a running agent and a grain control agent, configures a compound running agent and a compound grain control agent, realizes the preparation of a high-performance matte electrolytic copper foil, solves the problems of high stress and high warping of a traditional double-bright electrolytic copper foil, and has a lower surface roughness of the copper foil, a matte surface with moderate brightness consistent with a bright surface, and good flexibility, low warping, a roughness Rz of less than 1.0 μm, a high-temperature tensile strength of more than 450 MPa, and an elongation of more than 6.0%, reduces edge tearing during the foil production process, effectively improves the yield, and has a simple production control process and low cost. DETAILED DESCRIPTION

[0016] To make the purpose, technical scheme and advantages of the present application clearer, the present application will be further described in detail.

[0017] The compound additive of the present application is used in the manufacture of a matte electrolytic copper foil, the electrolyte has a copper ion content of 60-120 g / L, a sulfuric acid content of 90-150 g / L, a temperature of 45-55℃, and a current density of 50-75 A / dm 2 The compound additive is added in the production process, and a conventional electrolytic copper foil electrodeposition process is used to produce different specifications of products by controlling the linear speed.

[0018] Example 1

[0019] (1) Clean cathode copper plates or copper wires are placed in a copper dissolving tank in a staggered manner, low-copper high-acid electrolyte is pumped in, and compressed air is blown into the tank bottom. The copper dissolving reaction releases heat, and the temperature in the tank can reach 50-90℃, obtaining high-copper low-acid electrolyte;

[0020] (2) The electrolyte from the electrolysis machine platform, plus the high-copper low-acid electrolyte supplemented according to the metering concentration, flows into the contaminated liquid tank, and the powdered activated carbon is quantitatively added, which flows into the clean liquid tank through the diatomaceous earth filter and the precision filter in turn through the contaminated liquid pump;

[0021] (3) The additive solution is added to the clean liquid tank according to the metering through the metering pump, and the clean liquid electrolyte is obtained after stirring uniformly, wherein the concentrations of the additives are as follows: brightener sodium polydithiopropyl sulfone (SPS) 0.8 mg / L, walking agent compounded hydrolyzed gelatin 12 mg / L, grain control agent (glucose, polyglycerol) 0.5 mg / L, and chloride ion 20 mg / L, wherein the compounded hydrolyzed gelatin is obtained by compounding low molecules with a molecular weight of about 3000 and high molecules with a molecular weight of about 25000 at a ratio of 1:0.8, and the grain control agent is obtained by mixing glucose and polyglycerol at a ratio of 1:1.

[0022] (4) The clean liquid electrolyte flows into the electrolysis machine platform through the clean liquid pump high tank at a constant flow rate to perform power-on roll plating of the copper foil semi-finished product, and the electrolyte flows back to the copper dissolving tank and the contaminated liquid tank.

[0023] (5) The copper foil semi-finished product is subjected to pickling, washing, anti-oxidation treatment, baking, winding, slitting, and packaging to obtain the copper foil finished product.

[0024] Example 2:

[0025] The process of this example is basically the same as that of Example 1, and the main difference is that in step (3), the concentrations of the additives are as follows: brightener sodium polydithiopropyl sulfone (SPS) 1.5 mg / L, walking agent compounded hydrolyzed gelatin 6.0 mg / L, grain control agent (glucose, polyglycerol) 1.0 mg / L, and chloride ion 25 mg / L, wherein the compounded hydrolyzed gelatin is obtained by compounding low molecules with a molecular weight of about 4000 and high molecules with a molecular weight of about 20000 at a ratio of 1:1, and the grain control agent is obtained by mixing glucose and polyglycerol at a ratio of 1:1.

[0026] Example 3:

[0027] The process of this example is basically the same as that of Example 1, and the main difference is that in step (3), the concentrations of the additives are as follows: brightener sodium polydithiopropyl sulfone (SPS) 2 mg / L, walking agent compounded hydrolyzed gelatin 8 mg / L, grain control agent (glucose, polyglycerol) 2.5 mg / L, and chloride ion 30 mg / L, wherein the compounded hydrolyzed gelatin is obtained by compounding low molecules with a molecular weight of about 5000 and high molecules with a molecular weight of about 15000 at a ratio of 1:1, and the grain control agent is obtained by mixing glucose and polyglycerol at a ratio of 1:1.

[0028] Example 4:

[0029] The process of this example is substantially the same as that of Example 1, the main difference being that in step (3), the concentrations of the additives are: brightener sodium polydithiopropyl sulfone (SPS) 3 mg / L, walking agent compound hydrolyzed gelatin 2 mg / L, grain control agent 5 mg / L, chloride ion 35 mg / L, wherein the compound hydrolyzed gelatin is obtained by compounding low molecules with molecular weight of about 4000 and high molecules with molecular weight of about 25000 at a ratio of 1:1.2, and the grain control agent is obtained by mixing glucose and polyglycerol at a ratio of 1:1.

[0030] Example 5:

[0031] The process of this example is substantially the same as that of Example 1, the main difference being that in step (3), the concentrations of the additives are: brightener sodium polydithiopropyl sulfone (SPS) 2.5 mg / L, walking agent compound hydrolyzed gelatin 8 mg / L, grain control agent 3.5 mg / L, chloride ion 50 mg / L, wherein the compound hydrolyzed gelatin is obtained by compounding low molecules with molecular weight of about 4000 and high molecules with molecular weight of about 20000 at a ratio of 1:1, and the grain control agent is obtained by mixing glucose and polyglycerol at a ratio of 1:1.

[0032] Example 6:

[0033] The process of this example is substantially the same as that of Example 1, the main difference being that in step (3), the concentrations of the additives are: brightener sodium polydithiopropyl sulfone (SPS) 1.5 mg / L, walking agent compound hydrolyzed gelatin 5 mg / L, grain control agent 3 mg / L, chloride ion 40 mg / L, wherein the compound hydrolyzed gelatin is obtained by compounding low molecules with molecular weight of about 5000 and high molecules with molecular weight of about 25000 at a ratio of 1:0.8, and the grain control agent is obtained by mixing glucose and polyglycerol at a ratio of 1:1.

[0034] Comparative Example 1:

[0035] The process of this example is substantially the same as that of Example 1, the main difference being that in step (3), the concentrations of the additives are: brightener sodium polydithiopropyl sulfone (SPS) 1.5 mg / L, walking agent hydrolyzed gelatin 6.0 mg / L, grain control agent polyglycerol 1.0 mg / L, chloride ion 25 mg / L, wherein the hydrolyzed gelatin is a low molecule with molecular weight of about 4000.

[0036] Comparative Example 2:

[0037] The process of this embodiment is substantially the same as that of embodiment 1, the main difference is that in step (3), the concentrations of the additives are as follows: brightener sodium polydithiopropyl sulfone (SPS) 1.5 mg / L, leveling agent hydrolyzed gelatin 6.0 mg / L, grain control agent polyglycerol 1.0 mg / L, and chloride ion 25 mg / L, wherein the hydrolyzed gelatin has a molecular weight of about 25000.

[0038] Comparative example 3:

[0039] The process of this embodiment is substantially the same as that of embodiment 1, the main difference is that in step (3), the concentrations of the additives are as follows: brightener sodium polydithiopropyl sulfone (SPS) 1.5 mg / L, leveling agent hydrolyzed gelatin 6.0 mg / L, grain control agent polyglycerol 1.0 mg / L, and chloride ion 25 mg / L, wherein the hydrolyzed gelatin has a molecular weight of about 25000.

[0040] Comparative example 4:

[0041] The process of this embodiment is substantially the same as that of embodiment 1, the main difference is that in step (3), the concentrations of the additives are as follows: brightener sodium polydithiopropyl sulfone (SPS) 1.5 mg / L, leveling agent hydrolyzed gelatin 6.0 mg / L, grain control agent polyglycerol 1.0 mg / L, and chloride ion 25 mg / L, wherein the hydrolyzed gelatin has a molecular weight of about 25000.

[0042] The performance test results of the electrolytic copper foil prepared in each embodiment and comparative example are shown in Table 1. According to the results in Table 1, compared with the matte electrolytic copper foil prepared using a single leveling agent and grain control agent (comparative examples 1 and 2) and the double-sided photoelectric copper foil (comparative examples 3 and 4), the matte electrolytic copper foil prepared by using the additive brightener sodium polydithiopropyl sulfone (SPS) 0.8-3.0 mg / L, the leveling agent compounded hydrolyzed gelatin (compounded by low molecular weight 3000-5000 and high molecular weight 15000-25000 at a ratio of 1:0.8-1.2), the grain control agent (mixed by glucose and polyglycerol at a ratio of 1:1), and the chloride ion 20-50 mg / L, all show low warpage, low surface roughness, and excellent mechanical properties, the roughness Rz is less than 1.0 μm, the high temperature tensile strength is greater than 450 MPa, and the elongation is greater than 6.0%. The present application is different from the single additive control method of the brightener, leveling agent and grain control agent in the traditional electrolytic copper foil preparation process, and a plurality of additives are used to compound the leveling agent and the grain control agent, to realize the preparation of high-performance matte electrolytic copper foil, and to solve the problems of high stress and high warpage of traditional double-sided photoelectric electrolytic copper foil, and the surface roughness of the copper foil is lower.

[0043] Table 1. Test results of the properties of electrolytic copper foils prepared in each of the examples and comparative examples

[0044]

[0045] The above description is merely that of the preferred embodiments of the application and is not intended to limit the scope of the application. Therefore, equivalents, modifications, and variations of the described embodiments encompassed by the spirit and scope of the following claims are within the scope of the present application.

Claims

1. A method for producing a matte electrolytic copper foil, characterized by It comprises the following steps: (1) take clean cathode copper plate or copper wire, staggered into the copper dissolving tank, pump into low copper high acid electrolyte, tank bottom into compressed air, get high copper low acid electrolyte; (2) through the electrolyte of foil machine table, plus the high copper low acid electrolyte supplemented according to the measured concentration, flow into the dirty liquid tank, quantitative addition of powder activated carbon, through the dirty liquid pump, diatomite filter, precision filter, flow into the clean liquid tank; (3) through the metering pump according to the measured addition of additive solution to the clean liquid tank, stirring uniform, obtain clean electrolyte, the concentration of each item of the additive is: brightener 0.8-3.0 mg / L, walking agent 2.0-12.0 mg / L, grain control agent 0.5-5.0 mg / L, chloride ion 20-50 mg / L; (4) the above clean electrolyte through the clean liquid pump high tank, constant flow to the foil machine table, power roller plated foil, control the rotation line speed, stripping out of copper foil semi-finished product, electrolyte backflow to the copper dissolving tank and dirty liquid tank; (5) the copper foil semi-finished product through pickling, washing, anti oxidation treatment, baking, winding, cutting, packaging, get copper foil finished product; In step (3), the brightener is polydithiopropane sulfonic acid sodium, the walking agent is complex hydrolyzed gelatin, and the grain control agent is glucose and polyglycerol; The complex hydrolyzed gelatin is obtained by compounding low molecular weight of 3000-5000 and high molecular weight of 15000-25000 in a ratio of 1:0.8-1.2; The ratio of glucose and polyglycerol in the grain control agent is 1:1.

Images