Study On The Effects Of Electrolytic Process On Microstructure And Properties Of Electrolytic Copper Foils

With the development and popularization of new energy vehicles,how to produce lithium-ion batteries with good cycle performance and high energy density has become a hot research topic.The cathode of lithium-ion power battery is mainly composed of electrolytic copper foils,which plays the role of carrying the anode material of the battery and transporting the electron.The mechanical properties and surface properties of electrolytic copper foils affect the safety and practicability of battery seriously.In the process of electrolytic copper foils production,the electrolytic process parameters and additives have a great influence on the micro structure and properties of electrolytic copper foils,and the size effect of thickness has obvious effect on the properties of copper foils.Therefore,the effects of relative electrolytic parameters(current density,copper ion concentration,temperature)and additives(2-Mercaptobenzimidazole,isinglass)on the microstructure and properties of electrolytic copper foils and were systematically studied in this paper,microstructure and properties of copper foils with different thickness were also studied.When the current density is 0.08-0.26A/m2,with the increase of current density,the protruding particles on the surface of copper foils with the thickness of 12?m increase,and the sharp degree of the particles on the surface increases.When the current density is less than 0.14A/m2,the preferred degree of(220)crystal plane increases with the increase of current density,and when the current density is greater than 0.14A/m2,the preferred degree of(220)crystal plane decreases with the increase of current density.With the increase of current density,the strength and elongation of copper foils decrease first and then increase,and the strength of copper foils decreases when the grain size increases and the orientation of(220)crystal plane is high.The copper foil has the best mechanical properties when the current density is 0.26A/m2 with the tensile strength is 428MPa and the elongation is 5.9%.When the concentration of Cu2+ is 81-93g/L,the bulge particles on the surface of copper foils with the thickness of 12?m increase with the increase of Cu2+ concentration.The increase of copper ion concentration does not change the preferred orientation of electrolytic copper foils.When the concentration of copper ion increases from 81g/L to 84g/L,the grain size of copper foils decreases,the tensile strength and elongation of copper foils increase.When the concentration of Cu2+ increases from 84g/L to 93g/L,the grain size of copper foils increases,and the tensile strength and elongation decrease.When the copper ion concentration is 84g/L,the copper foil has the best mechanical properties,the tensile strength is 397MPa,and the elongation is 6.1%.When the electrolyte temperature is from 48? to 56?,the roughness of copper foils surface decrease with the increase of temperature,and the change of electrolyte temperature has no effect on the preferred orientation of the crystal face of copper foil.When the temperature is less than 50 °C,the grain size of copper foil decreases,the tensile strength and elongation increase with the increase of temperature,and when the temperature is higher than 50 ?,the grain size of copper foils increases and the tensile strength and elongation decrease.When the temperature is 50 ?,the copper foil has the best mechanical properties,the tensile strength is 354 MPa,and the elongation is 4.8%When the concentration of 2-Mercaptobenzimidazole is in 2mg/L-6mg/L,the surface roughness of copper foils decreases with the increase of the additive concentration.However,when the concentration of 2-Mercaptobenzimidazole is in 6-10mg/L,the particles on the surface of copper foils grow up abnormally and the roughness increases with the increase of the concentration of the additive.At the same time,the grain size of the copper foils can be enlarged by the additive.The mechanical properties of copper foils are reduced.When the concentration of isinglass is in 1-5mg/L,the particles on the surface of copper foils become fine with the increase of isinglass concentration.At the same time,the grain size of copper foils decreases obviously with the increase of isinglass concentration,and the mechanical property of copper foils is improved.At the same time,the optimum mechanical property of copper foils is 2-Mercaptobenzimidazole 2mg/L and isinglass 5mg/L when two kinds of compound additives were added at the same time.When the thickness of copper foils is 6-70?m,the thickness of copper foils increases,and the orientation of the crystal plane changes from(220),(111),(311)to(220)orientation.When the thickness of copper foils is less than 18?m,the mechanical properties of copper foils are obviously affected by size effect.The copper foil with the thickness of 18?m has the highest strength,and the tensile strength at this time is 330 MPa.When the thickness of copper foil is greater than 18?m,the high degree of preference of the crystal face orientation reduces the strength of the copper foils.The elongation of the copper foils increases as the thickness of the copper foil increases.