Iron-phosphate-based lithium-ion battery positive plate and preparation method thereof

Abstract

The invention provides an iron-phosphate-based lithium-ion battery positive plate and a preparation method thereof. The iron-phosphate-based lithium-ion battery positive plate comprises an anode current collector, iron-phosphate-based lithium-ion particles, conducting solvent and adhesive and is characterized in that the anode current collector is an aluminium foil which forms pores by corrosion, the grain diameter of the iron-phosphate-based lithium-ion particle is from nanometer to micron scale, and the adhesive is the mixture of organic conducting high polymer adhesive and the non-conducting high polymer adhesive. The iron-phosphate-based lithium-ion battery positive plate of the invention improves the bonding performance between an anode material and the anode current collector aluminium foil, improves pole piece conducting performance and improves the situation of uneven pole piece impedance.

Description

technical field [0001] The invention relates to a lithium iron phosphate lithium ion battery and a preparation method thereof, in particular to a lithium iron phosphate lithium ion battery positive plate and a preparation method thereof. Background technique [0002] In lithium-ion batteries, the selection and quality of cathode materials play a decisive role in the performance and price of lithium-ion batteries. Lithium cobalt oxide (LiCoO 2 ), lithium manganese oxide (LiMn 2 o 4 ), lithium nickel oxide (LiNiO 2 ), nickel-cobalt-manganese polylithium compound and lithium iron phosphate (LiFePO 4 ), among which LiFePO4 is gradually being used in electric vehicles, aerospace, energy storage and other fields because of its low price, environmental protection, excellent cycle performance, and good material stability. [0003] For lithium-ion batteries using different oxides as positive electrode materials, the composition and structure of the battery, the negative electrod...

AI Technical Summary

Problems solved by technology

[0006] However, for the lithium iron phosphate lithium ion battery whose size is determined, although the bonding tightness between the lithium iron phosphate powder material and the collector can be satisfied by increasing the amount of binder, the amount of active material is relatively reduced. As a result, the energy density of lithium iron phosphate lithium-ion batteries is reduced

In addition, in the positive electrode sheet of lithium iron phosphate lithium battery, the binder is usually polyvinyl alcohol (PVA), polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), sodium carboxymethyl cellulose (CMC), These are all electrically insulating polymer compounds. For lithium iron phosphate lithium-ion batteries with defined dimensions, when the amount of binder increases, it needs to be between the content of conductive agent (usually graphite, acetylene black) and the amount of active material. A compromise is made, so that the prepared electrode sheet cannot achieve very ideal performance as a whole

At the same time, the increase in the amount of non-conductive polymer material binder increases the insulation of the pole piece to a certain extent, which leads to an increase in the internal resistance of the pole piece and affects the rate performance of the battery.