阅读说明：本技术 一种隔膜及其制备方法以及二次电池 (Diaphragm, preparation method thereof and secondary battery ) 是由 屈永辉 纪荣进 李聪 郑明清 陈杰 杨山 于 2021-08-13 设计创作，主要内容包括：本发明属于隔膜技术领域,尤其涉及一种隔膜及其制备方法以及二次电池,包括以下步骤：S1配料搅拌：将各原料按量投加,搅拌反应得到浆料；S2涂布：将浆料涂布在基膜的至少一侧面得到第一半成品膜；S3烘烤：将第一半成品膜在真空下烘烤得到第二半成品膜；S4加湿：将第二半成品膜加湿得到隔膜。本发明的一种隔膜的制备方法,能有效地祛除静电,减少不良率,提高隔膜质量,降低生产成本。(The invention belongs to the technical field of diaphragms, and particularly relates to a diaphragm, a preparation method thereof and a secondary battery, which comprises the following steps: s1, mixing and stirring: adding the raw materials according to the amount, and stirring for reaction to obtain slurry; s2 coating: coating the slurry on at least one side of the base film to obtain a first semi-finished film; s3 baking: baking the first semi-finished film under vacuum to obtain a second semi-finished film; s4 humidification: and humidifying the second semi-finished film to obtain the diaphragm. The preparation method of the diaphragm can effectively remove static electricity, reduce reject ratio, improve the quality of the diaphragm and reduce production cost.)

1. A method for preparing a separator, comprising the steps of:

s1, mixing and stirring: adding the raw materials according to the amount, and stirring for reaction to obtain slurry;

s2 coating: coating the slurry on at least one side of the base film to obtain a first semi-finished film;

s3 baking: baking the first semi-finished film under vacuum to obtain a second semi-finished film;

s4 humidification: and humidifying the second semi-finished film to obtain the diaphragm.

2. The method for preparing a separator according to claim 1, wherein in the humidifying step of S4, the humidity of the humidification is 80% to 100%.

3. The method for preparing the separator according to claim 1, wherein the moisture content of the separator prepared in S4 is 3000-4000 ppm.

4. The method for producing a separator according to claim 1, wherein the S4 humidification uses an industrial humidification tank.

5. The preparation method of the diaphragm according to claim 1, wherein the stirring temperature in the S1 material stirring is 20-28 ℃, and the stirring time is 1-6 hours.

6. The preparation method of the separator according to claim 1, wherein the solid content of the slurry prepared in the S1 batch stirring is 30-50%.

7. The method for preparing the diaphragm according to claim 1, wherein the degree of vacuum in the baking of S3 is-101 kPa to-150 kPa, the baking temperature is 50 ℃ to 60 ℃, and the baking time is 0.2 hour to 1.5 hours.

8. The method for preparing a separator according to claim 1, further comprising cutting the separator obtained after humidification into separators of a specified width, and rolling and storing the cut separators.

9. A separator produced by the method for producing a separator according to any one of claims 1 to 8.

10. A secondary battery characterized by comprising the separator as recited in claim 9.

Technical Field

The invention belongs to the technical field of diaphragms, and particularly relates to a diaphragm, a preparation method of the diaphragm and a secondary battery.

Background

The manufactured finished diaphragm has larger static electricity, so that the wrinkling and folding problems are caused when the diaphragm is contacted with a roller and a pole piece of equipment in the winding process, the safety problem of products is caused, the yield is reduced, and the production cost is increased.

The existing solution to the problem in the industry is to provide a static removing rod, an anti-static device is added on a roller of the equipment, the implementation process of the measures is difficult to control, the static removing device can only remove a small part of static, the effectiveness cannot be guaranteed, and the method and the equipment have high cost. Even if the static removing device is additionally used, a bad diaphragm caused by static still exists, and the defect rate cannot be effectively solved.

Disclosure of Invention

One of the objects of the present invention is: aiming at the defects of the prior art, the preparation method of the diaphragm is provided, which can effectively remove static electricity, reduce reject ratio, improve the quality of the diaphragm and reduce production cost.

In order to achieve the purpose, the invention adopts the following technical scheme:

a method of making a separator comprising the steps of:

s1, mixing and stirring: adding the raw materials according to the amount, and stirring for reaction to obtain slurry;

s2 coating: coating the slurry on at least one side of the base film to obtain a first semi-finished film;

s3 baking: baking the first semi-finished film under vacuum to obtain a second semi-finished film;

s4 humidification: and humidifying the second semi-finished film to obtain the diaphragm.

The existing industry has static removing rods aiming at the static treatment solution of the isolating membrane, the static preventing device is additionally arranged on the roller of the equipment, the implementation process of the measures is difficult to control, the static removing device can only remove a few static electricity, the effectiveness cannot be greatly guaranteed, the reject ratio reaches about 1 percent, and the measure cost is high. The invention adds the step of humidifying the isolating membrane on the basis of the original diaphragm manufacturing process, the humidifying step is mainly added after the baking step is finished, the humidifying process mainly acts on increasing the humidity of the isolating membrane, effectively eliminates the static problem of the diaphragm and ensures that the isolating membrane does not fold or wrinkle in the process of contacting the pole piece in the winding process. Compared with the prior art, the technology effectively solves the problem of static electricity of the isolating film, the reject ratio generated by the static electricity is reduced to be less than or equal to 0.1 percent, and the process cost is reduced by 60 percent compared with the prior static electricity removing measure.

As an improvement of the preparation method of the diaphragm of the present invention, in the step of humidifying S4, the humidity of the humidification is 80% to 100%. The humidity of the humidifying step is set, so that the humidity of the membrane after humidification can be controlled, the membrane has baked viscosity, and static electricity can be effectively removed.

As an improvement of the preparation method of the diaphragm, the moisture content of the diaphragm prepared by S4 is 3000-4000 ppm. The moisture of the diaphragm is controlled, so that the diaphragm can keep certain viscosity and can effectively remove static electricity. The moisture content of the diaphragm is accurately controlled to be 3000-4000 ppm, otherwise the viscosity of the diaphragm is easy to deteriorate, and the quality is affected.

As an improvement of the preparation method of the diaphragm, the S4 humidification uses an industrial humidification box. The humidity that industry adds the incubator can accurate control humidification avoids the diaphragm humidification excessive, makes the diaphragm become soft, is difficult to the rollup, and the diaphragm quality damages even.

As an improvement of the preparation method of the diaphragm, the stirring temperature in the S1 ingredient stirring is 20-28 ℃, and the stirring time is 1-6 hours. In the step, the ingredients react to obtain the diaphragm, and the reaction temperature and the stirring time are controlled simultaneously, so that the ingredients and the product form circulation, gas, liquid and suspended particles in reactants are uniformly mixed, the prepared diaphragm is beneficial to being continuously humidified after being baked, the quality is not influenced, and static electricity is also removed.

As an improvement of the preparation method of the diaphragm, the solid content of the slurry prepared in the S1 burdening and stirring process is 30-50%. The solid content is controlled to ensure that the coating is smoother, and the performance of the prepared diaphragm is better. Preferably, the slurry solids content is 35% to 45%, more preferably, the slurry solids content is 40%.

As an improvement of the preparation method of the diaphragm, the vacuum degree in the S3 baking process is-101 kPa to-150 kPa, the baking temperature is 50 ℃ to 60 ℃, and the baking time is 0.2 hour to 1.5 hours. Controlling a certain vacuum degree to enable gas in the diaphragm to escape in the baking process, so that the diaphragm has certain mechanical properties; the diaphragm quality is better by controlling certain temperature and time.

The preparation method of the diaphragm is an improvement of the preparation method of the diaphragm, and the preparation method of the diaphragm further comprises the steps of cutting the humidified diaphragm into diaphragms with specified widths, and rolling and storing the cut diaphragms. And longitudinally cutting the prepared diaphragm into rolls with required width according to actual requirements, and finishing the roll separation through final rolling.

The second purpose of the invention is: aiming at the defects of the prior art, the diaphragm is provided, static electricity is less prone to wrinkling, folding is not prone to occurring during rolling, and storage and use are convenient.

In order to achieve the purpose, the invention adopts the following technical scheme:

a diaphragm is prepared by the preparation method of the diaphragm.

The third purpose of the invention is that: aiming at the defects of the prior art, the secondary battery is provided, the diaphragm has good smoothness, the ionic conductivity is effectively improved, and the service life is long.

In order to achieve the purpose, the invention adopts the following technical scheme:

a secondary battery includes the separator.

Compared with the prior art, the invention has the beneficial effects that: the preparation method of the diaphragm can effectively remove static electricity, reduce reject ratio, improve the quality of the diaphragm and reduce the production cost.

Drawings

Fig. 1 is a schematic view of a manufacturing process of the separator of the present invention.

Fig. 2 is a schematic flow diagram of the preparation of a prior art separator.

Detailed Description

The present invention will be described in further detail with reference to the following detailed description and the accompanying drawings, but the embodiments of the invention are not limited thereto.

Example 1

A method of making a separator comprising the steps of:

s1, mixing and stirring: adding the raw materials according to the amount, and stirring for reaction to obtain slurry;

s2 coating: coating the sizing agent on two side surfaces of the base film to obtain a first semi-finished film;

s3 baking: baking the first semi-finished film under vacuum to obtain a second semi-finished film;

s4 humidification: humidifying the second semi-finished film to obtain the diaphragm, wherein the preparation flow is shown in figure 1.

In the humidifying step of S4, the humidifying humidity is 90%.

Wherein the moisture content of the separator prepared in S4 is 3000 ppm.

Wherein, the S4 uses an industrial humidifying box for humidifying.

Wherein the stirring temperature in the S1 ingredient stirring is 25 ℃, and the stirring time is 4 hours.

Wherein the solid content of the slurry prepared in the S1 burdening and stirring process is 40%.

Example 2

A method of making a separator comprising the steps of:

s1, mixing and stirring: adding the raw materials according to the amount, and stirring for reaction to obtain slurry;

s2 coating: coating the sizing agent on two side surfaces of the base film to obtain a first semi-finished film;

s3 baking: baking the first semi-finished film under vacuum to obtain a second semi-finished film;

s4 humidification: and humidifying the second semi-finished film to obtain the diaphragm.

In the humidifying step of S4, the humidifying humidity is 80%.

Wherein the moisture content of the separator prepared by the S4 is 3200 ppm.

Wherein, the S4 uses an industrial humidifying box for humidifying.

Wherein the stirring temperature in the S1 ingredient stirring is 20 ℃, and the stirring time is 1 hour.

Wherein the solid content of the slurry prepared in the S1 burdening and stirring process is 30 percent.

Example 3

A method of making a separator comprising the steps of:

s1, mixing and stirring: adding the raw materials according to the amount, and stirring for reaction to obtain slurry;

s2 coating: coating the sizing agent on two side surfaces of the base film to obtain a first semi-finished film;

s3 baking: baking the first semi-finished film under vacuum to obtain a second semi-finished film;

s4 humidification: and humidifying the second semi-finished film to obtain the diaphragm.

In the humidifying step of S4, the humidifying humidity is 85%.

Wherein the moisture content of the separator prepared by the S4 is 3500 ppm.

Wherein, the S4 uses an industrial humidifying box for humidifying.

Wherein the stirring temperature in the S1 ingredient stirring is 25 ℃, and the stirring time is 3 hours.

Wherein the solid content of the slurry prepared in the S1 burdening and stirring process is 35%.

Example 4

A method of making a separator comprising the steps of:

s1, mixing and stirring: adding the raw materials according to the amount, and stirring for reaction to obtain slurry;

s2 coating: coating the slurry on at least one side of the base film to obtain a first semi-finished film;

s3 baking: baking the first semi-finished film under vacuum to obtain a second semi-finished film;

s4 humidification: and humidifying the second semi-finished film to obtain the diaphragm.

In the humidifying step of S4, the humidifying humidity is 95%.

Wherein the moisture content of the separator prepared by the S4 is 3600 ppm.

Wherein, the S4 uses an industrial humidifying box for humidifying.

Wherein the stirring temperature in the S1 ingredient stirring is 26 ℃, and the stirring time is 5 hours.

Wherein the solid content of the slurry prepared in the S1 burdening and stirring process is 45%.

Example 5

A method of making a separator comprising the steps of:

s1, mixing and stirring: adding the raw materials according to the amount, and stirring for reaction to obtain slurry;

s2 coating: coating the sizing agent on two side surfaces of the base film to obtain a first semi-finished film;

s3 baking: baking the first semi-finished film under vacuum to obtain a second semi-finished film;

s4 humidification: and humidifying the second semi-finished film to obtain the diaphragm.

In the humidifying step of S4, the humidifying humidity is 90%.

Wherein the moisture content of the separator prepared by the S4 is 3800 ppm.

Wherein, the S4 uses an industrial humidifying box for humidifying.

Wherein the stirring temperature in the S1 ingredient stirring is 28 ℃, and the stirring time is 3 hours.

Wherein the solid content of the slurry prepared in the S1 burdening and stirring process is 48 percent.

Example 6

A method of making a separator comprising the steps of:

s1, mixing and stirring: adding the raw materials according to the amount, and stirring for reaction to obtain slurry;

s2 coating: coating the sizing agent on two side surfaces of the base film to obtain a first semi-finished film;

s3 baking: baking the first semi-finished film under vacuum to obtain a second semi-finished film;

s4 humidification: and humidifying the second semi-finished film to obtain the diaphragm.

In the humidifying step of S4, the humidifying humidity is 100%.

Wherein the moisture content of the diaphragm prepared by the S4 is 4000 ppm.

Wherein, the S4 uses an industrial humidifying box for humidifying.

Wherein the stirring temperature in the S1 ingredient stirring is 21 ℃, and the stirring time is 1 hour.

Wherein the solid content of the slurry prepared in the S1 burdening and stirring process is 50%.

Example 7

A method of making a separator comprising the steps of:

s1, mixing and stirring: adding the raw materials according to the amount, and stirring for reaction to obtain slurry;

s2 coating: coating the sizing agent on two side surfaces of the base film to obtain a first semi-finished film;

s3 baking: baking the first semi-finished film under vacuum to obtain a second semi-finished film;

s4 humidification: and humidifying the second semi-finished film to obtain the diaphragm.

In the humidifying step of S4, the humidifying humidity is 95%.

Wherein the moisture content of the separator prepared by the S4 is 4000 ppm.

Wherein, the S4 uses an industrial humidifying box for humidifying.

Wherein the stirring temperature in the S1 ingredient stirring is 22 ℃, and the stirring time is 6 hours.

Wherein the solid content of the slurry prepared in the S1 burdening and stirring process is 50%.

Example 8

A method of making a separator comprising the steps of:

s1, mixing and stirring: adding the raw materials according to the amount, and stirring for reaction to obtain slurry;

s2 coating: coating the slurry on one side of the base film to obtain a first semi-finished film;

s3 baking: baking the first semi-finished film under vacuum to obtain a second semi-finished film;

s4 humidification: and humidifying the second semi-finished film to obtain the diaphragm.

In the humidifying step of S4, the humidifying humidity is 80%.

Wherein the moisture content of the diaphragm prepared by the S4 is 3200 ppm.

Wherein, the S4 uses an industrial humidifying box for humidifying.

Wherein the stirring temperature in the S1 ingredient stirring is 24 ℃, and the stirring time is 2 hours.

Wherein the solid content of the slurry prepared in the S1 burdening and stirring process is 40%.

The preparation method of the diaphragm further comprises the steps of cutting the humidified diaphragm into diaphragms with specified widths, and rolling and storing the cut diaphragms.

Comparative example 1

The difference from example 1 is that: a method of making a separator comprising the steps of:

s1, mixing and stirring: adding the raw materials according to the amount, and stirring for reaction to obtain slurry;

s2 coating: coating the slurry on at least one side of the base film to obtain a first semi-finished film;

s3 baking: and baking the first semi-finished film under vacuum to obtain the diaphragm.

The preparation method of the diaphragm further comprises the steps of cutting the prepared diaphragm into diaphragms with specified widths, rolling and storing the cut diaphragms, wherein the preparation process is shown in figure 2.

The rest is the same as embodiment 1, and the description is omitted here.

And (3) performance testing:

the separators prepared in examples 1 to 8 were subjected to an electrostatic test with the separator prepared in comparative example 1, and the electrostatic voltage applied to the prepared separators was measured, and the results are shown in table 1.

TABLE 1

Item	Example 1	Example 2	Example 3	Example 4	Example 5
						Electrostatic voltage (V)	863	894	889	892	891
Item	Example 6	Example 7	Example 8	Comparative example 1	/
						Electrostatic voltage (V)	892	887	893	2550	/

The method for preparing the diaphragm can effectively remove static electricity, so that the prepared diaphragm has low static voltage, and compared with the diaphragm prepared in the comparative example 1, the static voltage of the diaphragm prepared in the invention is as low as 863V, and 66.1V lower than 2550V of the diaphragm prepared in the comparative example 1, so that the static electricity of the diaphragm is greatly reduced, and the reject ratio of the diaphragm is reduced to 0.1%, so that the problems of wrinkling and folding of the diaphragm caused by static electricity are effectively solved, and the practicability is good. And as can be seen from the comparison of examples 1-8, when the preparation parameters are controlled as in example 1, that is, when the solid content of the slurry prepared in the burdening and stirring of step S1 is 40%, the stirring temperature is 25 ℃, the stirring time is 4 hours, the humidification humidity is 90% in the humidification step of step S4, and the moisture of the diaphragm prepared in step S4 is 3000ppm, the electrostatic voltage of the prepared diaphragm is lower and is only 863V, the performance is better, and the fraction defective is more effectively reduced.

Variations and modifications to the above-described embodiments may also occur to those skilled in the art, which fall within the scope of the invention as disclosed and taught herein. Therefore, the present invention is not limited to the above-mentioned embodiments, and any obvious improvement, replacement or modification made by those skilled in the art based on the present invention is within the protection scope of the present invention. Furthermore, although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.