A kind of pet non-woven fabric-based composite lithium-ion battery diaphragm with nanopore and preparation method thereof

Abstract

The invention discloses a PET non-woven fabric-based composite lithium-ion battery diaphragm with a nano-pore size and a preparation method thereof. The lithium-ion battery diaphragm of the invention is composed of the following raw materials: a hydrophilic PET non-woven fabric base material and a polymer , small pores of 1-500nm are evenly distributed on the hydrophilic PET non-woven fabric base material, the porosity is 50-70%, and the polymer is filled in the small pores of the hydrophilic PET non-woven fabric base material, so The high molecular polymer is polyvinyl alcohol or sodium hydroxymethyl cellulose; the high molecular polymer is filled in the pores of the PET hydrophilic non-woven fabric by means of ultrasonic, vacuum impregnation, and hot rolling after low temperature drying. , the PET non-woven fabric-based composite lithium-ion battery separator with nanopores of the present invention has the advantages of high porosity, small thermal shrinkage, small lithium ion mass transfer resistance, and excellent electrochemical performance. The preparation of the present invention The method has few steps, is easy to operate, does not involve the use of toxic reagents in the preparation process, has high safety, is suitable for PET hydrophilic non-woven fabrics with various surface densities and high air permeability as a base material, and can realize industrial production.

Description

technical field [0001] The invention relates to the technical field of electrochemical power sources, in particular to a PET non-woven fabric-based composite lithium-ion battery diaphragm with a nanometer aperture and a preparation method thereof. Background technique [0002] With the market's rapid demand for new energy electric vehicles and power energy storage devices, lithium-ion batteries are being developed in the direction of high-rate rapid charge and discharge. However, the existing lithium-ion battery separators are mostly made of polyethylene and polypropylene materials, which are only suitable for It is suitable for small mobile electrical equipment such as mobile phones and tablet computers, but not suitable for large electrical equipment such as electric vehicles, unmanned aerial vehicles, and spacecraft, because the porosity of polyolefin separators is low, generally less than 40%, and cannot be used for lithium A large number of fast transitions of ions prov...

AI Technical Summary

Problems solved by technology

[0002] With the market's rapid demand for new energy electric vehicles and power energy storage devices, lithium-ion batteries are being developed in the direction of high-rate rapid charge and discharge. However, the existing lithium-ion battery separators are mostly made of polyethylene and polypropylene materials, which are only suitable for It is suitable for small mobile electrical equipment such as mobile phones and tablet computers, but not suitable for large electrical equipment such as electric vehicles, unmanned aerial vehicles, and spacecraft, because the porosity of polyolefin separators is low, generally less than 40%, and cannot be used for lithium A large number of fast transitions of ions provide channels. In addition, lithium-ion batteries will generate a lot of heat during fast charging under high-rate conditions, while polyolefin separators have poor thermal stability, and the melting temperature is lower than 170 ° C. Excessive temperature It will cause the melting deformation of the diaphragm and cause danger due to the internal short circuit of the lithium-ion battery. Therefore, it is urgent to develop a large-scale power lithium-ion battery with good thermal stability and excellent mechanical stability;

[0003] PET non-woven fabric-based lithium-ion battery separators take advantage of the advantages of PET non-woven fabrics in thermal stability, large pore size and wide distribution, but the existing PET non-woven fabric-based lithium-ion battery separators make the polymer very difficult due to capillary force and other reasons. It is difficult to completely fill the pores of the non-woven fabric, and the polymer is mostly covered on the surface of the non-woven fabric, and cannot be completely filled in the pores of the non-woven fabric. Therefore, the prepared composite materials are mostly layered structures, and the filling effect on the pores of the non-woven fabric Limited, and the larger pores are easy to make the positive and negative electrodes of the lithium-ion battery contact and short-circuit, which is also the biggest problem facing the non-woven fabric-based lithium-ion battery separator materials at present.

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