Lithium iron phosphate anode material and lithium iron phosphate secondary battery

Abstract

The invention relates to the technical field of lithium ion batteries, in particular to a lithium iron phosphate anode material and a lithium iron phosphate secondary battery. The lithium iron phosphate anode material is prepared from, by weight, 70-92 parts of lithium iron phosphate, 0-8 parts of scattered conductive agents, 0-8 parts of concentrated conductive agents, 0-20 parts of collaborative conductive agents, 1-6 parts of binding agents and 0-2 parts of other auxiliaries. The positive electrode of the lithium iron phosphate secondary battery is prepared from the lithium iron phosphate anode material. According to the lithium iron phosphate anode material, the scattered conductive agents, the concentrated conductive agents and the collaborative conductive agents are compounded and used in a multi-dimensional mode, a complete conductive and bonding network is built, the internal resistance of the lithium iron phosphate secondary battery can be basically not increased or slightly increased when large capacity discharge is conducted, and the power of the lithium iron phosphate secondary battery is increased, and the cycle life of the lithium iron phosphate secondary battery is prolonged. The internal resistance of the lithium iron phosphate secondary battery can be basically not increased or slightly increased when large capacity discharge is conducted, the power is high, and the cycle life is long.

Description

technical field [0001] The invention relates to the technical field of lithium ion batteries, in particular to a lithium iron phosphate cathode material and a lithium iron phosphate secondary battery. Background technique [0002] Lithium iron phosphate is limited by the shortcomings of small particles, large specific surface area and poor conductivity, resulting in uneven powder mixing of the lithium iron phosphate electrode body and poor interface adhesion between the powder coating layer and the conductive substrate, resulting in large discharge resistance and storage When the internal resistance increases rapidly, the lithium iron phosphate battery will eventually fail. [0003] The uneven powder mixing process of the electrode body has been mature and well applied. The problem of poor adhesion between the powder coating layer and the conductive substrate interface has always restricted the development of lithium iron phosphate batteries, especially lithium iron phosphat...

AI Technical Summary

Problems solved by technology

At present, there are two methods that can partially solve this problem: one is to use carbon-coated aluminum foil, which can reduce the growth rate of battery internal resistance, but there are inherent defects of high process cost, limited applicability and the introduction of impurities, and only some products have been marketed. The second is to use etched aluminum foil to increase the surface area and enhance the adhesion, but this method has limited effects, and at the same time reduces the mechanical strength of the aluminum foil and introduces impurities, which brings difficulties in operation

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