Automotive lithium battery diaphragm and preparation method thereof

Abstract

The invention relates to a lithium battery diaphragm and a preparation method thereof. The lithium battery diaphragm has a multilayer structure, an organic polymer nuclear pore membrane serves as a base membrane, modified graphene oxide membranes are compounded on two sides of the base membrane, and a closed layer membrane is compounded on the outer layer of the graphene oxide membrane; the organic polymer nuclear pore membrane adopts a polyester (PET) nuclear pore membrane, a high density polyethylene nuclear pore membrane or an ultra-high molecular weight polyethylene nuclear pore membrane. The battery diaphragm disclosed by the invention has uniform pore structure and pore distribution as well as high porosity; due to the addition of the modified graphene oxide material, the hydrophilic performance of the membrane layer is improved, the environment adaptability of the diaphragm is improved, the resistance is reduced, and the battery efficiency is improved. Moreover, using metallic materials is avoided, and environmental hazards caused by the electrolyte membrane are reduced.

Description

technical field [0001] The invention relates to the field of battery diaphragms and manufacturing methods thereof, in particular to lithium battery diaphragms for new energy vehicles and their preparation methods. Background technique [0002] In recent years, fuel cells as a next-generation energy source have been in the spotlight. In particular, a polymer electrolyte fuel cell (PEFC) using a proton-conductive polymer membrane as an electrolyte is expected to be widely used in cogeneration systems for household use, power supplies for portable devices, and power supplies for automobiles due to its high energy density. use in the field. The electrolyte membrane of PEFC is required to function as an electrolyte that conducts protons between the fuel electrode and the oxidation electrode, and is also required to be a partition wall that separates the fuel supplied to the fuel electrode from the oxidant supplied to the oxidation electrode. When the function as either the elec...

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Problems solved by technology

However, this type of diaphragm has many shortcomings: PE and PP have high crystallinity and low polarity, and the electrolyte uses a highly polar organic solvent. Therefore, the affinity between the diaphragm and the electrolyte is not good, and it is almost impossible to Swelled by the electrolyte, that is, most of the electrolyte exists in the pores in liquid form, so the electrolyte is prone to leakage; the porosity is low, and because PP and PE have no solvent at room temperature, the separator can only be prepared by melt stretching at present , the stretching method not only has extremely high requirements on equipment, but also it is difficult to obtain a high-porosity film, resulting in high film resistance; the temperature resistance is limited, usually lower than 150 ° C, which reduces the safety of lithium batteries; in order to further improve the lithium battery The specific energy of ion batteries needs to reduce the thickness of the film, which reduces the liquid absorption rate of the film with two-dimensional pore structure and affects the safety.

There are still very few reports on the application of nuclear pore membranes to battery separators, because the preparation of nuclear pore membranes requires special equipment, such as the use of tandem accelerators to irradiate the membranes, which is not available to ordinary companies for production, so research in this area is limited. many

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