High-compaction-resistant composite conductive agent and application thereof in lithium ion battery

Abstract

The invention relates to the technical field of lithium ion batteries, in particular to a high-compaction-resistant composite conductive agent and application thereof in a lithium ion battery. The composite conductive agent comprises a porous conductive agent and other conductive agents, the porous conductive agent is a carbon material, and the particle size of the carbon material is micron-sizedor sub-micron-sized; other conductive agents are selected from one or more of acetylene black, carbon black, Ketjen black, conductive graphite, graphene, carbon nanotubes, carbon nanowires, Super P and KS-6, wherein the mass ratio of the porous conductive agent to other conductive agents is 5: 95-95: 5. Under the condition of high compaction density, the integrity of main material particles in a material layer is ensured; meanwhile, the composite conductive agent is beneficial to increase of pores among active material particles in the coating, the porous surface of the composite conductive agent is beneficial to infiltration of electrolyte, and the pores in the electrode are not liable to block in the high-compaction rolling process so that good wettability between the pole piece and theelectrolyte can be guaranteed, and the performance of the battery is improved.

Description

technical field [0001] The invention relates to the technical field of lithium-ion batteries, in particular to a high-pressure-resistant composite conductive agent and its application in lithium-ion batteries. Background technique [0002] As a new type of green secondary battery, lithium-ion batteries have the advantages of high energy density and environmental friendliness, and are widely used in portable electronic devices and power vehicle batteries. At present, the manufacturing process of lithium-ion secondary battery electrode pole piece is usually to coat the material layer on both sides of the current collector. With the demand for higher energy density and higher volume specific capacity of the battery, the pole piece is required to have a higher areal density and compacted density. [0003] CN109473623A discloses a manufacturing method of high compacted density pole pieces of lithium-ion batteries. The conductive mixed slurry is coated on the metal current collec...

AI Technical Summary

Problems solved by technology

However, the micron-sized porous carbon conductive agent has a high resistivity, and it cannot form a complete conductive network when used alone as a conductive agent. At the same time, it will lead to problems such as increased sheet resistance and reduced cycle performance.

[0005] For the existing conventional pole pieces, excessive compaction will lead to poor wettability of the pole piece, poor lithium ion transport and migration, and may lead to the rupture of the main material powder, resulting in a decline in battery performance; while in the prior art The process of repeated coating, drying, and rolling is complicated and inefficient, which limits production capacity, and the technology of introducing special current collectors or special additives increases the production cost to a certain extent

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