Hitachi Cable has developed by adding zirconium (Zr) for enhanced rolling copper, cathode active material for the use of silicon and other alloy materials, a new generation of lithium-ion rechargeable battery. Since the copper foil of the alloy has a strength capable of withstanding the negative electrode active material of the volume change, so it not only can be used for mobile terminals and other consumer products, is also expected for the hybrid vehicle use, etc..
Aimed at increasing the energy density of lithium-ion rechargeable battery means, there is the use of charge-discharge capacity than the current mainstream silicon-carbon-like material such as alloy type of material, as the negative electrode collector body fixation on the surface of copper foil of the negative active material technology. But the alloy type of material in the discharge of the volume change is greater than the carbon-like material, repeated charge and discharge when the copper foil by the stress, resulting in negative active material and lead foil strip, resulting in shortened life expectancy. And in order to improve the energy density, the general use of the thickness of 8 ~ 10μm thin copper foil, a new generation of lithium-ion rechargeable batteries, also called thin to achieve the same degree. Therefore need to develop a higher strength of copper foil, to resist the negative electrode alloy material volume change.
Hitachi Cable products, select from the existing elastic limit stress of high and excellent processability copper alloy “HCL02Z”, as the development of basic materials. HCL02Z containing 0.02% Zr, with the original copper anode materials used in high purity copper and electrolytic copper foil rolling than the more intense. In addition, in order to further increase with the negative active material of the adhesion, but also on the HCL02Z of rolled products were surface treatment. With trial batteries evaluation tests confirmed that no plastic deformation occurs, the battery life when compared with the use of electrolytic copper foil extending more than 10%. Representative HCL02Z tensile strength 450N/mm2, the minimum thickness of 6μm, maximum width of 570mm.