Polyene microporous multilayer diaphragm and manufacturing method thereof

Abstract

The invention provides a polyene microporous multilayer diaphragm and a manufacturing method thereof. The diaphragm is formed by combing three or more than three polyene layers, wherein in a plurality of polyene layers, at least one polyene layer is a polyethylene layer, and at least one polyene layer is a polypropylene layer; the polyethylene layer and the polypropylene layer are tightly attached to each other; and in adjacent polyethylene and polypropylene layers, at least one layer is a polymer blend layer which contains a certain amount of ethylene-propylene copolymer. The invention has the advantages that: in the integrated structure of the polyene microporous multilayer diaphragm, the properties of porosity, puncture strength, pore size, ventilation ratio, tensile strength, breaking elongation and the like are also identical to the high properties of a single-layer diaphragm; simultaneously, the defects of the single-layer diaphragm is overcome, namely the safety of the diaphragm is improved.

Description

technical field [0001] The invention relates to the manufacturing field of lithium-ion batteries, and more specifically refers to a kind of polyene microporous multilayer separator for lithium-ion batteries and a manufacturing method thereof. Background technique [0002] Microporous plastic films can be used in different fields. For example, used as separator films for non-electrolytic batteries, such as lithium-ion batteries, electrolytic capacitor separators, electrical equipment insulation, artificial lung diaphragms, plasma cleaners, breathable patient gowns, filters for isolating organisms and viruses from water, gas mixture isolation membrane, or air conditioner filter. [0003] In 1991, SONY successfully launched the first commercial lithium-ion battery, triggering a new generation of rechargeable batteries. Lithium-ion batteries are currently widely used in portable electronic products, especially notebook computers and mobile phones. Compared with nickel-cadmium ...

AI Technical Summary

Problems solved by technology

Although the melting point of PE is low, compared with PP, its early closure characteristics, that is, lower closed cell temperature and higher resistance after closed cell (the increase in resistance after closed cell is about 3 times higher than that at room temperature) order of magnitude), making PE suitable for the separator of lithium-ion batteries, so it is mainly used in current lithium-ion batteries, but it is only made of PE (ultra-high molecular weight PE, HDPE, a mixture of ultra-high molecular weight PE and HDPE) The temperature at which the pores of the formed microporous membrane disappear is low, and the membrane rupture temperature is also low, so it cannot be considered to be safe.

However, the microporous membrane made of PP alone is less safe because of the higher temperature at which the micropores disappear.

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