CN109742294A

CN109742294A - A kind of preparation method of cellulosic separator

Info

Publication number: CN109742294A
Application number: CN201811599301.5A
Authority: CN
Inventors: 程跃; 熊磊; 傅尧
Original assignee: Jiangxi Tongrui New Energy Technology Development Co Ltd
Current assignee: Jiangxi Tongrui New Energy Technology Development Co Ltd
Priority date: 2018-12-25
Filing date: 2018-12-25
Publication date: 2019-05-10
Anticipated expiration: 2038-12-25
Also published as: CN109742294B

Abstract

The present invention relates to a kind of preparation methods of cellulosic separator, the specific steps are that: (1) cellulose and diluent are mixed to prepare mixed solution by weight 40:60~90:10；(2) mixture solution made from step (1) is put into batch mixer, at normal temperature, stirs 15~20min under the revolving speed of 1000rpm, forms aaerosol solution；(3) aaerosol solution made from step (2) is put into extruder, is squeezed out, is cast, filtered；(4) by the filtered film in step (3), it is sent to baking oven, at 90~100 DEG C, is dried under conditions of 0.1~1Mpa, finally winds, obtains diaphragm to be prepared.The cellulosic separator of the application preparation, immersion liquid is good, and electrolyte reduces the internal resistance of lithium ion battery in the abundant infiltration of membrane surface, and battery is made to possess good cycle performance and higher charge-discharge performance；The cellulosic separator of the application, broken film temperature with higher are conducive to the security performance for improving battery.

Description

A kind of preparation method of cellulosic separator

Technical field

The present invention relates to diaphragm production technical fields, are a kind of preparation methods of cellulosic separator specifically.

Background technique

Cellulose (cellulose) be by glucose group at macromolecular polysaccharide.Not soluble in water and common organic solvents.It is The main component of plant cell wall.Cellulose is that a kind of most wide, content is most polysaccharide is distributed in nature, accounts for plant kingdom's carbon and contains 50% or more of amount.The content of cellulose of cotton is close to 100%, for natural most pure cellulose source.In general timber, fiber Element accounts for 40~50%, and there are also 10~30% hemicellulose and 20~30% lignin.

Cellulose is one of the main chemical compositions in paper pulp and paper, is had using the specialties that cellulose is produced as raw material There are many good characteristics, such as dielectric constant is high, puncture is strong, chemical stability is good, thermostabilization is good, degradable.In recent years, Many film researchers are being dedicated to studying the High-performance diaphragm using cellulose as raw material.

Currently, diaphragm material used in lithium ion battery is mainly polyethylene (PE), the polyene that polypropylene (PP) is representative Hydro carbons.Dry method is mainly based on PP, and wet process is mainly based on PE.Polyalkene diaphragm has lot of advantages, such as good mechanical property, electricity Chemical property is good, but the feature high due to its heat-shrinkable, influences whether safety in lithium ion battery use process, especially right It is particularly important in power battery.In addition, the hydrophobic property of polyalkene diaphragm causes electrolyte that cannot sufficiently soak, influence between diaphragm Ion transmit so that influence battery multiplying power stability.Although the diaphragm after existing coating improves it to a certain extent Thermal contraction and immersion liquid, but also substantially increase the production cost of lithium battery diaphragm.

Therefore lithium battery diaphragm is prepared as raw material using cellulose, had great significance to lithium electricity industry.From raw material On from the point of view of, cellulose origin is abundant, stablizes, environmentally protective, cost is much smaller compared with polyolefine material.From properties of product on It says, cellulosic separator has immersion liquid good, is heat-shrinked performance low and resistant to high temperature.These can make up existing polyolefin every Defect present in film.

In addition, cellulosic separator can also be applied because of the aperture of its good hydrophilicity and uniform, controllable in Shui Chu In reason field.

Summary of the invention

It is an object of the invention to overcome the deficiencies of the prior art and provide a kind of preparation methods of cellulosic separator.

The purpose of the present invention is achieved through the following technical solutions:

A kind of preparation method of cellulosic separator, which is characterized in that the specific steps are that:

(1) cellulose and diluent are mixed to prepare mixed solution by weight 40: 60~90: 10；

(2) mixture solution made from step (1) is put into batch mixer, is stirred at normal temperature, under the revolving speed of 1000rpm 15~20min is mixed, aaerosol solution is formed；

(3) aaerosol solution made from step (2) is put into extruder, is squeezed out, is cast, filtered.

(4) by the filtered film in step (3), be sent to baking oven, at 90~100 DEG C, under conditions of 0.1~1Mpa into Row drying, finally winds, and obtains diaphragm to be prepared.

Specifically, the diluent is one or more of mixtures of water, alcohol, ether, acetone, benzene etc..

Specifically, cellulose described in the step (1) is lignin, fento cellulose or cellulose family nanometer One or more of mixtures of fiber；The fibre diameter of cellulose is 5~100 microns.

Specifically, the condition of stirring described in step (2) be room temperature under, 10000rpm or more, mixing time be 15~ 20min。

Specifically, condition dry described in step (3) is 90~100 DEG C, 0.5~1Mpa.

Specifically, the pore size of the diaphragm can be adjusted between 10~100nm.

Specifically, the porosity of the diaphragm can be adjusted between 20%~70%.

Specifically, the thickness of the diaphragm can be adjusted between 10~100 microns.

Specifically, the broken film temperature of the diaphragm is 180 DEG C or more.

Cellulosic separator can also be applied because of the aperture of its good hydrophilicity and uniform, controllable in water treatment field In.

Compared with prior art, the positive effect of the present invention is:

(1) cellulosic separator prepared by the present invention is used, immersion liquid is good, abundant infiltration of the electrolyte in membrane surface, drop The low internal resistance of lithium ion battery, makes battery possess good cycle performance and higher charge-discharge performance；

(2) cellulosic separator prepared by the present invention is used, broken film temperature with higher is conducive to the safety for improving battery Performance；

(3) cellulosic separator prepared by the present invention is used, thermal contraction performance is good, can keep diaphragm at a higher temperature Integrality, prevent the short circuit of battery, improve the security performance of battery.

Detailed description of the invention

Fig. 1: production technological process；

Fig. 2: simple machine flow chart.

The label in accompanying drawing is:

1 extruder,

2 peelable casting supports,

3 pumping and filtering devices,

4 drying equipments,

5 winding devices,

6 first scrapers,

7 second scrapers.

Specific embodiment

A kind of specific embodiment of the preparation method of cellulosic separator of the present invention presented below.

Embodiment 1

Diaphragm provided in this embodiment is using lignin as raw material, and water is the diaphragm of diluent preparation, and membrane thicknesses are 12 microns, porosity 52%, is heat-shrinked MD 1%, TD 0.5%. by 185 DEG C of broken film temperature

Diaphragm provided in this embodiment is obtained according to the following steps:

2kg lignin fibre is put into 3kg water, under the revolving speed of 10000rpm, stirring 15min to cellulose, which suspends, to be divided It dissipates in water.Suspension is poured into extruder 1, is squeezed out by die head, is cast on peelable casting support 2, then pass through Pumping and filtering device 3 is filtered, and extracts moisture out, is formed film, while carrying out thickness control to it, is entered back into drying equipment 4, It is 93 DEG C, dry under conditions of 0.5Mpa, wind-up operation is then carried out by winding device 5, then respectively by the first scraper 6 and Second scraper 7 is cut, our desired 12 microns of diaphragms are finally obtained.

Embodiment 2

Diaphragm provided in this embodiment is using fento cellulose as raw material, and ethyl alcohol is the diaphragm of diluent preparation, every Film thickness is 16 microns, porosity 55%, 200 DEG C of broken film temperature, is heat-shrinked MD 1%, TD0.5%.

3.5kg lignin fibre is put into 1.5kg water, under the revolving speed of 12000rpm, stirring 20min is outstanding to cellulose It is floating to be dispersed in water.Suspension is poured into extruder, is squeezed out by die head, is cast on peelable carrier, then taken out Moisture is extracted in filter out, is formed film, while carrying out thickness control to it, is entered back into drier, at 90 DEG C, under conditions of 1Mpa It is dry, finally obtain our desired 16 microns of diaphragms.

Comparative example 1

Film production process is the production technology of existing wet process polyethylene lithium battery diaphragm, and membrane thicknesses are 12 microns.

Comparative example 2

Film production process is the production technology of existing wet process polyethylene lithium battery diaphragm, and membrane thicknesses are 16 microns.

Table 1: performance data table

The above is only a preferred embodiment of the present invention, it is noted that for the ordinary skill people of the art Member, without departing from the inventive concept of the premise, can also make several improvements and modifications, these improvements and modifications also should be regarded as In protection scope of the present invention.

Claims

1. a kind of preparation method of cellulosic separator, which is characterized in that the specific steps are that:

(2) mixture solution made from step (1) is put into batch mixer, stirs 15 at normal temperature, under the revolving speed of 1000rpm ~20min forms aaerosol solution；

(3) aaerosol solution made from step (2) is put into extruder, is squeezed out, is cast, filtered；

(4) by the filtered film in step (3), it is sent to baking oven, at 90~100 DEG C, is done under conditions of 0.1~1Mpa It is dry, it finally winds, obtains diaphragm to be prepared.

2. a kind of preparation method of cellulosic separator as claimed in claim 1, which is characterized in that the diluent be water, One or more of alcohol, ether, acetone, benzene mixture.

3. a kind of preparation method of cellulosic separator as claimed in claim 1, which is characterized in that institute in the step (1) The cellulose stated is lignin, fento cellulose or cellulose nano-fibrous one or more of mixtures；Cellulose Fibre diameter is 5~100 microns.

4. a kind of preparation method of cellulosic separator as claimed in claim 1, which is characterized in that stirred described in step (2) Condition be room temperature under, 10000rpm or more, mixing time be 15~20min.

5. a kind of preparation method of cellulosic separator as claimed in claim 1, which is characterized in that dry described in step (3) Condition be 90~100 DEG C, 0.5~1Mpa.

6. a kind of preparation method of cellulosic separator as claimed in claim 1, which is characterized in that the aperture of the diaphragm is big It is small to be adjusted between 10~100nm.

7. a kind of preparation method of cellulosic separator as claimed in claim 1, which is characterized in that the porosity of the diaphragm It is adjusted between 20%~70%.

8. a kind of preparation method of cellulosic separator as claimed in claim 1, which is characterized in that the thickness of the diaphragm exists It is adjusted between 10~100 microns.

9. a kind of preparation method of cellulosic separator as claimed in claim 1, which is characterized in that the rupture of membranes temperature of the diaphragm Degree is 180 DEG C or more.

10. a kind of cellulosic separator of the preparation method preparation of cellulosic separator is in water treatment field as claimed in claim 1 In application.