As the energy density of the power battery increases, the aluminum foil as a collector fluid is also becoming thinner and thinner, thus requiring a lower impurity content, less self-discharge, better thickness uniformity, higher surface tension, better bonding performance, thinner thickness, higher strength, higher conductivity, suitable elongation and other requirements, while in order to improve the content of active substances, aluminum foil surface coating technology is also developing rapidly, the following will briefly introduce these new technologies.
Coating technology: the use of functional coating on the battery conductive substrate surface treatment is a breakthrough technological innovation, overlaying carbon aluminum foil is a well-dispersed nano conductive graphite and carbon coated particles, uniformly and delicately coated on the aluminum foil. It provides excellent static conductivity and collects micro-currents from the active material, which can significantly reduce the contact resistance between the material and the collector, and can improve the adhesion between the two, which can reduce the amount of binder used, thus producing a significant improvement in the overall performance of the battery.
Through the coating technology, the stability of the interface can be significantly improved, enhancing the stability of the lithium-ion battery long cycle, has been applied in batch on some power battery products, in addition to this, there are some safety coating technology has gradually begun to apply.
Porous aluminum foil: With the development of technology, porous aluminum foil technology has come into being, which can carry more active materials and allow closer contact between active material particles.
As far as the current technology is concerned, porous aluminum foil has not been applied in large quantities, there are still difficulties in coating, low tensile strength, laminating broken belt, burr more resulting in large self-discharge and so on, further research and solutions are needed, although there are some small soft package data show that can significantly improve energy density, but Lao Li believes that there is still a certain degree of difficulty from industrialization, the need to optimize the pre-process manufacturing process of lithium-ion batteries to match this technology.