Lithium-ion battery separator and application thereof

Abstract

The invention belongs to the technical field of lithium-ion batteries, and particularly relates to a lithium-ion battery separator and an application thereof. The separator comprises a positive insulating layer, a negative insulating layer and a porous conductive layer arranged between the positive insulating layer and the negative insulating layer, wherein the porous conductive layer is at least one of a graphene layer, a carbon fiber layer, a carbon nanotube layer and a conductive carbon layer. Compared with the prior art, the lithium-ion battery separator has the advantages that: on one hand, a carbon material used by the porous conductive layer is high in flexibility, the flexibility and the stability of the separator can be improved, the carbon material has abundant micro-pores and is beneficial to transportation of lithium ions, and meanwhile, since the conductive carbon material is utilized by a positive electrode and a negative electrode, the compatibility of the separator and an internal system of the battery is better and the separator can stably exist without an effect on the safety performance of the battery; and on the other hand, the arranged porous conductive layer has the function, that a traditional separator does not have, of monitoring internal parameters of the battery, and the safety problem caused by an internal short circuit of the lithium-ion battery can be solved by the function to the greatest extent.

Description

technical field [0001] The invention belongs to the technical field of lithium ion batteries, and in particular relates to a lithium ion battery diaphragm and an application thereof. Background technique [0002] Lithium-ion batteries are widely used because of their high voltage, high specific energy, long life, no memory effect, and small self-discharge. However, portable electronic devices have higher and higher requirements on the energy density and charging speed of lithium-ion batteries. [0003] Among them, the negative electrode material has a great influence on the energy density of lithium-ion batteries. The currently commercialized lithium-ion battery anode materials are generally graphite, silicon alloy, tin alloy, etc., but their theoretical energy density is lower than that of metal lithium. Therefore, in recent years, the research and commercialization of lithium ion batteries using metal lithium as the negative electrode material are in full swing. At prese...

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Problems solved by technology

[0006] 1) The diaphragm itself must have micropores to ensure that lithium ions can freely travel between the positive and negative electrodes; while the metal itself is relatively dense, which is equivalent to adding a barrier layer in the middle of the diaphragm, which greatly increases the space for lithium ions to shuttle between them. difficulty;

[0007] 2) The flexibility of the metal is poor, and it is difficult to meet the good flexibility characteristics of the separator; moreover, it is difficult to compound the metal on the insulating substrate, and at the same time, the bonding strength is low, and the problem of interlayer peeling is easy to occur;

[0008] 3) The thickness of the metal layer cannot be made very thin unless electroplating is used, but it is difficult to perform electroplating on an insulating diaphragm substrate;

[0009] 4) Because the metal itself has an electrochemical window, setting a metal layer in the separator is equivalent to introducing an impurity source into the battery, which is quite dangerous and has low reliability and safety

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