The application of aluminum foil in lithium batteries and the advantages of aluminum foil in the field of lithium batteries. Aluminum foil is the key material in the positive electrode of lithium battery. The main material of the current collector of lithium-ion batteries is metal foil (such as copper foil, aluminum foil). Its function is to collect the current generated by the active substance of the battery to form a large current output. Therefore, the current collector should be in full contact with the active substance and the internal resistance should be as small as possible.


Application of aluminum foil in lithium batteries


The positive electrode sheet is lithium iron phosphate coated on aluminum foil, but lithium iron phosphate is preferred. The negative electrode is copper foil coated with graphite or lithium titanate. There is a separator between the positive and negative electrode foils and is wound together. The wound positive and negative sheets (including separators) are placed into the battery case, the electrolyte is injected, and then vacuum-packed to complete the production of a single battery.


In lithium batteries, copper foil is both a carrier of the negative electrode active material and a collection and conductor of negative electrode electrons. Therefore, it has special technical requirements, that is, it must have good conductivity, the surface can be evenly coated with the negative electrode material without falling off, and has good corrosion resistance. In order to ensure that the negative electrode material applied to the electrolytic copper foil will not fall off, a suitable binder must be added during preparation.


With the rapid development of the lithium battery market, the industry expects that the consumption of lithium battery aluminum foil will reach about 80,000 tons by 2020.


Lithium battery aluminum foil can be divided into power battery foil, consumer battery foil, and energy storage battery foil. Among them, power battery foil is currently in demand, accounting for more than 50%, while the consumer battery aluminum foil market is basically saturated. Industry analysts believe that the proportion of demand for power batteries in the future will further increase, and energy storage batteries will gradually make efforts.


Advantages of aluminum foil in the field of lithium batteries


1. Extend the service life of lithium-ion batteries, because special aluminum foil has better physical functions, the circulation function of lithium batteries has been significantly improved.


2. Improve the consistency of lithium batteries. Using special aluminum foil can not only reduce internal resistance, but also improve the consistency of internal resistance.


3. Improve the rate discharge function of the battery. After selecting special aluminum foil, the rate discharge function of the lithium battery will be significantly advanced, especially in the case of large magnification (greater than 3C), the rate discharge capacity will travel above 15%. Perhaps under the same rate, the special aluminum foil can travel the energy density of the lithium battery.


Advantages of carbon-coated aluminum foil in lithium battery applications: inhibit battery polarization, reduce thermal effects, and improve rate performance; reduce battery internal resistance, and significantly reduce the dynamic internal resistance increase of the cycle process; improve consistency, increase the cycle life of lithium batteries; improve the adhesion between active substances and current collectors, and reduce the manufacturing cost of electrode sheets; protect the current collector from being corroded by electrolyte; and improve the processing performance of lithium iron phosphate and lithium titanate materials.


Performance advantages of carbon-coated aluminum foil/copper foil: significantly improve the consistency of battery pack usage and greatly reduce battery composition costs; improve the adhesiveness of active materials and current collectors, the material is soft and easy to process, and reduce the manufacturing cost of the electrode sheet; reduce polarization, increase the magnification and gram capacity, improve the performance of lithium batteries; protect current collectors and extend the battery life.


Summary: It is predicted that China's electric vehicle ownership will account for more than 30% of the total ownership by 2030. China's new energy vehicle industry has opened up a new application field for the application of aluminum, with great potential and considerable usage. The lithium battery anode aluminum foil has no special requirements for the performance of aluminum foil, and China's aluminum foil industry can fully meet all requirements for this foil.