High temperature resistant battery diaphragm containing cellulose fiber substrate and preparation method thereof

Abstract

The invention discloses a high temperature resistant battery diaphragm containing a cellulose fiber substrate and a preparation method thereof. The high temperature resistant battery diaphragm has a thickness of 20-40micrometer, a porosity of 40-60%, and air permeability of 15-30sec / 100cc. The diaphragm includes a cellulose fiber substrate, a porous adhesive layer and an inorganic coating. The preparation method includes: subjecting an aqueous polyurethane emulsion to mechanical foaming, conveying a foam glue to a foam bath device, immersing the cellulose fiber substrate by traction into foambath for gluing, and letting the foam glue form the porous adhesive layer on the substrate surface; coating the cellulose fiber substrate and the porous adhesive layer with an inorganic paint, conducting compounding to form an inorganic coating; and performing drying. The high temperature resistant battery diaphragm provided by the invention has the advantages of good imbibition and liquid retention ability, no shrinkage, longitudinal and horizontal hot shrinkage both below 2%, high ion penetrability, low resistance, excellent mechanical properties, and stable electrochemical properties, and can prevent battery short circuit and dendrite piercing.

Description

technical field [0001] The invention relates to a high-temperature-resistant battery separator containing cellulose fiber base material and a preparation method thereof, belonging to the technical field of lithium-ion batteries. Background technique [0002] At present, lithium-ion battery separator materials are mainly polyolefin separators such as single-layer polypropylene (PP) microporous membranes, single-layer polyethylene (PE) microporous membranes and three-layer PP / PE / PP composite membranes. Mainly dry stretching porogenic method and wet phase separation method. The disadvantages of polyolefin separators are: 1. The polyolefin separator is easy to shrink when heated, which will cause the size of the separator to be unstable, and the positive and negative electrodes will be short-circuited by direct contact; 2. The closed cell temperature and membrane rupture temperature are low. Under normal conditions, a large amount of heat is released inside the battery, causing...

AI Technical Summary

Problems solved by technology

However, the diaphragm is easy to lose powder during vibration, curling and folding, and the consistency of the diaphragm is poor

The invention patent applied by Xiamen University with the publication number CN1312789C uses Celgard2400 as the substrate, and the mixed solution of nano-SiO2, polyoxyethylene, and acetonitrile as the coating for the diaphragm coating to prepare a composite battery diaphragm, but the substrate used in the diaphragm needs to be imported. , leading to an increase in production costs

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