CN111231359A - Battery diaphragm, and production method and production equipment of battery diaphragm - Google Patents

Abstract

The application discloses production equipment and a production method of a battery diaphragm and the battery diaphragm. The extruder is used for melting and extruding the raw material of the diaphragm to obtain the base film. The oven is used for annealing the base film. The compound roller is used for compounding the multiple base films subjected to annealing treatment to form a compound film. The drawing roller group comprises a cold drawing section, a hot drawing section and a shaping section, the cold drawing section comprises a first pressing roller and a cold drawing roller, the hot drawing section comprises a second pressing roller and a hot drawing roller, the shaping section comprises a third pressing roller and a shaping roller, and at least one of the first pressing roller, the second pressing roller and the third pressing roller adopts a heating roller so that the front side and the back side of the composite film are heated uniformly. First compression roller, second compression roller and/or third compression roller have the heating function for the tow sides of tensile in-process complex film are heated evenly, have effectively improved the uniformity of battery diaphragm.

Description

Battery diaphragm, and production method and production equipment of battery diaphragm

Technical Field

The application relates to the technical field of battery diaphragms, in particular to a battery diaphragm, a production method of the battery diaphragm and production equipment of the battery diaphragm.

Background

The lithium ion battery has the characteristics of good safety, higher energy density, suitability for heavy current discharge and the like, and is widely applied to a plurality of fields of digital products, electric bicycles, electric motorcycles, electric automobiles, power energy storage, communication energy storage and the like. The lithium battery mainly comprises four parts, including a positive plate, a negative plate, an isolating membrane (diaphragm) and electrolyte. The lithium battery isolating membrane plays a role in isolating the positive electrode and the negative electrode in the battery and conducting ions, and is one of important components of the lithium battery.

The consistency of the battery diaphragm is one of important factors for evaluating the quality of the battery diaphragm, in the actual production, a range judgment method is generally used for evaluating the consistency of the battery diaphragm, specifically, in the experiment, a plurality of layers of battery diaphragms have 3-20 layers, are jointly stretched and formed at one time, generally test the air permeability value from one side to the other side of each layer of diaphragm in the transverse direction, and finally judge the bad consistency by the range of the air permeability value. The interlayer air permeability value of the existing battery diaphragm is usually more than 70S, but with the improvement of science and technology, the requirement on the consistency of the battery diaphragm is higher and higher, and the existing battery diaphragm cannot meet the requirement on high consistency.

Disclosure of Invention

The application provides a battery diaphragm, a production method and production equipment of the battery diaphragm, and aims to solve the problem that the existing battery diaphragm is not high in consistency.

The application provides a production facility of battery diaphragm includes:

the extruder is used for melting and extruding the diaphragm raw material to obtain a base film;

the drying oven is used for carrying out annealing treatment on the base film;

the composite roller is used for compositing the multiple layers of base films subjected to annealing treatment to form a composite film;

and the stretching roller group, the stretching roller group includes cold drawing section, hot drawing section and design section for supply the complex film to loop through, with tensile complex film, and form the battery diaphragm, the cold drawing section includes first compression roller and cold drawing roller, first clearance that supplies the complex film to pass through has between first compression roller and cold drawing roller, the hot drawing section includes second compression roller and hot drawing roller, second compression roller and hot drawing roller have the second clearance that supplies the complex film to pass through, design section includes third compression roller and design roller, third compression roller and design roller have the third clearance that supplies the complex film to pass through between, at least one in first compression roller, second compression roller and the third compression roller adopts the warming mill, so that the positive and negative both sides of complex film are heated evenly.

As the further improvement of production facility, first compression roller, second compression roller and third compression roller all adopt the warming mill, the temperature of first compression roller is the same with the temperature of cold drawing roller, the temperature of second compression roller is the same with the temperature of hot drawing roller, the temperature of third compression roller is the same with the temperature of sizing roller.

As a further improvement of the production equipment, the temperatures of the first press roll and the cold drawing roll are both a, and the value range of a is as follows: a is more than or equal to 40 and less than or equal to 90 ℃.

As a further improvement of the production equipment, the temperatures of the second press roll and the hot drawing roll are both b, and the value range of b is as follows: b is more than or equal to 130 and less than or equal to 155 ℃.

As a further improvement of the production equipment, the temperatures of the third press roll and the setting roll are both c, and the value range of c is as follows: c is more than or equal to 150 and less than or equal to 170 ℃.

As a further improvement of the production equipment, the number of layers of the composite film is d, and the value range of d is as follows: d is more than or equal to 3 and less than or equal to 20 layers.

As a further improvement of the production equipment, the drawing and unreeling speed of the drawing roller group is e, and the value range of e is more than or equal to 2 and less than or equal to 10 m/min.

As a further improvement of the production equipment, the raw material of the diaphragm comprises at least one of polypropylene, polyethylene, polyacrylonitrile and poly-4-methylpentene.

The production method of the battery separator is applied to the separator production equipment in any one of the above items, and comprises the following steps:

a casting extrusion step: fusing and extruding a diaphragm raw material, and then collecting a long-roll base film;

annealing and heat treatment: placing the wound base film into a baking oven for baking heat treatment;

compounding: compounding the annealed base films, and compounding the multiple base films together to form a composite film roll;

a stretching step: the method comprises the following steps of sequentially stretching a composite film through a cold-drawing section, a hot-drawing section and a shaping section to obtain a battery diaphragm, wherein in the cold-drawing section, the composite film passes through a first gap between a first pressing roller and a cold-drawing roller, in the hot-drawing section, the composite film passes through a second gap between a second pressing roller and a hot-drawing roller, in the shaping section, the composite film passes through a third gap between a third pressing roller and a shaping roller, and at least one of the first pressing roller, the second pressing roller and the third pressing roller adopts a heating roller so that the front side and the back side of the composite film are uniformly heated;

layering: and (3) layering the multilayer battery diaphragm prepared by stretching to obtain a single-layer battery diaphragm.

The application provides a battery diaphragm, use as above-mentioned any one the diaphragm production method makes, the battery diaphragm's interlayer transverse ventilation value range is f, and the value range of f is: f is more than or equal to 20 and less than or equal to 60S.

The beneficial effect of this application:

the application provides a production facility of battery diaphragm, including extruder, oven, compound roller and drawing roller group. The extruder is used for melting and extruding the raw material of the diaphragm to obtain the base film. The oven is used for annealing the base film. The compound roller is used for compounding the multiple base films subjected to annealing treatment to form a compound film. The drawing roller group comprises a cold drawing section, a hot drawing section and a shaping section, the composite film is used for sequentially passing through, the composite film is drawn, a battery diaphragm is formed, the cold drawing section comprises a first pressing roller and a cold drawing roller, a first gap for the composite film to pass through is formed between the first pressing roller and the cold drawing roller, the hot drawing section comprises a second pressing roller and a hot drawing roller, a second gap for the composite film to pass through is formed between the second pressing roller and the hot drawing roller, the shaping section comprises a third pressing roller and a shaping roller, a third gap for the composite film to pass through is formed between the third pressing roller and the shaping roller, at least one of the first pressing roller, the second pressing roller and the third pressing roller adopts a heating roller, and the front side and the back side of the composite film are uniformly heated. First compression roller, second compression roller and/or third compression roller have the heating function for the tow sides of tensile in-process complex film are heated evenly, have effectively improved the uniformity of battery diaphragm.

Drawings

Fig. 1 is a schematic structural view of a production apparatus for a battery separator according to an embodiment of the present application.

Reference numerals: 100. a cold-drawing section; 110. a first press roll; 120. cold drawing the roller; 200. a hot-drawing section; 210. a second press roll; 220. hot drawing roller; 300. a shaping section; 310. a third press roll; 320. a shaping roller; 400. an unwinding section; 500. a base film; 600. compounding film; 700. a battery separator; 800. and (4) compounding the roller.

Detailed Description

The present application is described in further detail in the following detailed description of the preferred embodiments with reference to the figures, in which like elements in different embodiments are numbered with like associated element numbers. In the following description, numerous details are set forth in order to provide a better understanding of the present application. However, those skilled in the art will readily recognize that some of the features may be omitted or replaced with other elements, materials, methods in different instances. In some instances, certain operations related to the present application have not been shown or described in detail in order to avoid obscuring the core of the present application from excessive description, and it is not necessary for those skilled in the art to describe these operations in detail, so that they may be fully understood from the description in the specification and the general knowledge in the art.

Furthermore, the features, operations, or characteristics described in the specification may be combined in any suitable manner to form various embodiments. Also, the various steps or actions in the method descriptions may be transposed or transposed in order, as will be apparent to one of ordinary skill in the art. Thus, the various sequences in the specification and drawings are for the purpose of describing certain embodiments only and are not intended to imply a required sequence unless otherwise indicated where such sequence must be followed.

The numbering of the components as such, e.g., "first", "second", etc., is used herein only to distinguish the objects as described, and does not have any sequential or technical meaning. The term "connected" and "coupled" when used in this application, unless otherwise indicated, includes both direct and indirect connections (couplings).

The consistency of the current battery diaphragm is not high enough, and is more and more difficult to satisfy the demand of technical development, in order to promote the consistency of battery diaphragm, the inventor has carried out a series of research and experiments, and the inventor finds that when drawing the diaphragm, the steel roller needs to be heated, and the compression roller matched with the steel roller does not have the heating function, and then leads to in the tensile process, and the diaphragm positive and negative is heated inhomogeneous, influences the uniformity of product.

The embodiment provides a production device of a battery diaphragm.

Referring to fig. 1, the manufacturing apparatus includes an extruder (not shown), an oven (not shown), a compounding roll 800, and a drawing roll group.

The extruder is used for melting and extruding the raw material of the diaphragm to obtain the base film 500. The oven is used to anneal the base film 500. The laminating roller 800 is used to laminate the annealed multi-layered base film 500 to form the composite film 600. The drawing roller group comprises a cold drawing section 100, a hot drawing section 200 and a shaping section 300, and is used for enabling the composite film 600 to sequentially pass through so as to draw the composite film 600 and form the battery diaphragm 700, the cold drawing section 100 comprises a first pressing roller 110 and a cold drawing roller 120, a first gap for the composite film 600 to pass through is formed between the first pressing roller 110 and the cold drawing roller 120, the hot drawing section 200 comprises a second pressing roller 210 and a hot drawing roller 220, a second gap for the composite film 600 to pass through is formed between the second pressing roller 210 and the hot drawing roller 220, the shaping section 300 comprises a third pressing roller 310 and a shaping roller 320, a third gap for the composite film 600 to pass through is formed between the third pressing roller 310 and the shaping roller 320, and at least one of the first pressing roller 110, the second pressing roller 210 and the third pressing roller 310 adopts a heating roller so that the front side and the back side of the composite film.

The first pressing roller 110, the second pressing roller 210 and/or the third pressing roller 310 have a heating function, so that the front and back surfaces of the composite film 600 are uniformly heated in the stretching process, and the consistency of the battery separator 700 is effectively improved. Thereby improving the quality of the battery separator 700 and improving the safety of the battery separator 700 in lithium battery applications.

Specifically, the base film 500 may be a polypropylene microporous film, a polyethylene microporous film, or a multi-layer composite microporous film composed of polyethylene and polypropylene. The thickness of the base film 500 is 5-30um, the porosity is 30% -80%, and the pore diameter is 0.01-0.15 um. The polypropylene melt index is 0.5-3.5(g/10min, 230 ℃), the weight average molecular weight is 2X 105-5.5X 105, and the molecular weight distribution is 2-8. The polyethylene melt index is 0.5-3.0(g/10min, 190 deg.C), the weight average molecular weight is 1.1 × 105-4.5 × 105, and the molecular weight distribution is 2-6.

Specifically, the extrusion amount of the extrusion diaphragm raw material is 20-100kg/h, the extrusion temperature is 150-280 ℃, the die head temperature for extrusion is 160-260 ℃, the casting drafting speed during casting extrusion is 60-150m/min, and the temperature of the used casting roller is 60-95 ℃.

Specifically, during annealing heat treatment, the cast rolled base film 500 is put into an oven for baking heat treatment, wherein the baking temperature is 120-160 ℃, and the baking time is 8-20 h. The battery separator 700 having the same multilayer structure is obtained by stretching the composite film 600.

In actual production, the diaphragms with different pore structures can be regulated and controlled by adjusting the stretching multiplying power and the stretching temperature.

Referring to fig. 1, the cold-drawing stage 100, the hot-drawing stage 200, and the shaping stage 300 have different magnifications and temperatures, and the temperatures and magnifications of the drawing stages are matched. The stretching ratio of each section is realized by the speed difference between different steel rollers and the separation effect of the press roller. Steel rolls may be used for the cold drawing roll 120, the hot drawing roll 220, and the setting roll 320.

Referring to fig. 1, in an embodiment, the first press roller 110, the second press roller 210 and the third press roller 310 are heated rollers, the temperature of the first press roller 110 is the same as that of the cold drawing roller 120, the temperature of the second press roller 210 is the same as that of the hot drawing roller 220, and the temperature of the third press roller 310 is the same as that of the setting roller 320.

In a more specific embodiment, the heating temperature interval of the first press roller 110, the second press roller 210 and the third press roller 310 can reach 350 ℃ at most, the precision of the roller surface temperature is +/-0.5 ℃, each press roller can independently control the temperature, and the adopted material is a rubber roller with good heat conduction of a steel roller surface sleeve. The roll surface temperature of the cold drawing roll 120, the hot drawing roll 220 and the shaping roll 320 can be independently regulated and controlled, and the roll surface temperature deviation is less than 1 ℃.

Referring to fig. 1, in an embodiment, the heating roller is heated by at least one of oil temperature heating, resistance heating, and infrared heating.

Specifically, the cold drawing multiplying power is 1.05-1.3, the hot drawing multiplying power is 1.8-2.3, and the setting multiplying power is 0.7-0.95. The temperature of the cold drawing roller/the pressing roller is 40-90 ℃, the temperature of the hot drawing roller/the pressing roller is 155 ℃ in the temperature range, the temperature of the shaping roller/the pressing roller is 170 ℃ in the temperature range, and the stretching and unreeling speed is 2-10 m/min. The number of the stretched film rolls is 3 to 20.

Referring to fig. 1, in an embodiment, the temperatures of the first pressing roller 110 and the cold drawing roller 120 can be independently controlled, the temperatures of the first pressing roller 110 and the cold drawing roller 120 are both a, and a has a value range: a is more than or equal to 40 and less than or equal to 90 ℃.

Referring to fig. 1, in an embodiment, the temperatures of the second pressing roller 210 and the hot drawing roller 220 can be independently controlled, the temperatures of the second pressing roller 210 and the hot drawing roller 220 are both b, and the value range of b is as follows: b is more than or equal to 130 and less than or equal to 155 ℃.

Referring to fig. 1, in an embodiment, the temperatures of the third pressing roller 310 and the sizing roller 320 can be independently controlled, the temperatures of the third pressing roller 310 and the sizing roller 320 are both c, and the value range of c is as follows: c is more than or equal to 150 and less than or equal to 170 ℃.

Referring to fig. 1, in an embodiment, the number of layers of the composite film 600 is d, and d has a value range: d is more than or equal to 3 and less than or equal to 20 layers.

Specifically, the method comprises the following steps. In this embodiment, 4 layers of membranes are combined together, and in other embodiments, 5, 6 or any other suitable number of layers within the range may be combined together.

Referring to fig. 1, in an embodiment, a manufacturing apparatus includes an unwinding section 400, the unwinding section 400 is provided with a plurality of rolls of base films 500, the base films 500 extend from the unwinding section 400 to a compound roller 800 to be stacked, and the compound roller 800 is used for compounding to form a compound film 600.

Referring to FIG. 1, in an embodiment, the stretch unwinding speed of the stretch roller set is e, and e is in a range of 2 ≦ e ≦ 10 m/min.

Referring to fig. 1, in one embodiment, the separator material includes at least one of polypropylene, polyethylene, polyacrylonitrile, and poly-4-methylpentene.

On the other hand, the embodiment also provides a production method of the battery separator.

The production method is applied to the diaphragm production equipment and comprises the following steps:

a casting extrusion step: fusing and extruding a diaphragm raw material, and then collecting a long-roll base film;

annealing and heat treatment: placing the wound base film into a baking oven for baking heat treatment;

compounding: compounding the annealed base films, and compounding the multiple base films together to form a composite film roll;

a stretching step: the method comprises the following steps of sequentially stretching a composite film through a cold-drawing section, a hot-drawing section and a shaping section to obtain a battery diaphragm, wherein in the cold-drawing section, the composite film passes through a first gap between a first pressing roller and a cold-drawing roller, in the hot-drawing section, the composite film passes through a second gap between a second pressing roller and a hot-drawing roller, in the shaping section, the composite film passes through a third gap between a third pressing roller and a shaping roller, and at least one of the first pressing roller, the second pressing roller and the third pressing roller adopts a heating roller so that the front side and the back side of the composite film are uniformly heated;

layering: and (3) layering the multilayer battery diaphragm prepared by stretching to obtain a single-layer battery diaphragm.

The method can be used for manufacturing the single-layer multi-layer diaphragm with the porosity distribution of 30-50% and the thickness of 5-30 um.

On the other hand, the embodiment also provides a battery diaphragm.

The battery diaphragm is manufactured by adopting the diaphragm production equipment and the production method, the interlayer transverse ventilation value range of the battery diaphragm is f, and the value range of f is as follows: f is more than or equal to 20 and less than or equal to 60S.

On the other hand, this example also provides data on specific examples and comparative examples obtained in practical use by some production apparatuses and production methods of battery separators.

In one embodiment, the press rolls at the cold drawing, hot drawing and hot setting of the stretcher are heated press rolls. The thickness of the single layer before stretching is 10 mu m, the unreeling speed is 5m/min, and the number of stretching rolls is 16. The temperature of the cold drawing roller is 50 ℃, the temperature of the hot drawing roller is 150 ℃, and the temperature of the setting roller is 160 ℃. The cold drawing press roll is 50 ℃, the hot drawing press roll is 150 ℃ and the shaping press roll is 160 ℃. The cold drawing multiplying power is 1.1, the hot drawing multiplying power is 1.9, and the setting multiplying power is 0.8. And layering the diaphragm after stretching to obtain the single-layer diaphragm. After the experiment, the interlayer air permeability value obtained by the test is very poor at 35S.

In a comparative example, stretching was performed using an apparatus without a heated press roll (press roll having no heating function). The thickness of the single layer before stretching is 10 mu m, the unreeling speed is 5m/min, and the number of stretching rolls is 16. The temperature of the cold drawing roller is 50 ℃, the temperature of the hot drawing roller is 150 ℃, and the temperature of the shaping roller is 160 ℃; the cold drawing compression roller, the hot drawing compression roller and the shaping compression roller are rollers without heating function; the cold drawing multiplying power is 1.1, the hot drawing multiplying power is 1.9, and the setting multiplying power is 0.8. And layering the diaphragm after stretching to obtain the single-layer diaphragm. The interlayer air permeability value obtained by the test after the experiment is very poor at 90S.

In one embodiment, the press rolls at the cold drawing, hot drawing and hot setting of the stretcher are heated press rolls. The thickness of the single layer before stretching is 10 mu m, the unreeling speed is 5m/min, and the number of stretching rolls is 16. The temperature of the cold drawing roller is 60 ℃, the temperature of the hot drawing roller is 155 ℃, and the temperature of the setting roller is 162 ℃. The cold drawing press roll is 60 ℃, the hot drawing press roll is 155 ℃, and the shaping press roll is 162 ℃. The cold drawing multiplying power is 1.1, the hot drawing multiplying power is 1.9, and the setting multiplying power is 0.8. And layering the diaphragm after stretching to obtain the single-layer diaphragm. The interlayer air permeability value obtained by the test after the experiment is 28S.

In a comparative example, stretching was performed using an apparatus without a heated press roll (press roll having no heating function). The thickness of the single layer before stretching is 10 mu m, the unreeling speed is 5m/min, and the number of stretching rolls is 16. The temperature of the cold drawing roller is 60 ℃, the temperature of the hot drawing roller is 155 ℃, and the temperature of the setting roller is 162 ℃. The cold drawing press roller, the hot drawing press roller and the shaping press roller are rollers without heating function. The cold drawing multiplying power is 1.1, the hot drawing multiplying power is 1.9, and the setting multiplying power is 0.8. And layering the diaphragm after stretching to obtain the single-layer diaphragm. The interlayer air permeability value obtained by the test after the experiment is 70S.

In one embodiment, the press rolls at the cold drawing, hot drawing and hot setting of the stretcher are heated press rolls. The thickness of the single layer before stretching is 10 mu m, the unreeling speed is 5m/min, and the number of stretching rolls is 16. The temperature of the cold drawing roller is 80 ℃, the temperature of the hot drawing roller is 155 ℃, and the temperature of the setting roller is 162 ℃. The cold drawing press roll is 80 ℃, the hot drawing press roll is 155 ℃ and the shaping press roll is 162 ℃. The cold drawing multiplying power is 1.1, the hot drawing multiplying power is 1.9, and the setting multiplying power is 0.8. And layering the diaphragm after stretching to obtain the single-layer diaphragm. And the interlayer air permeability value is extremely poor 37S after the test.

In a comparative example, stretching was performed using an apparatus without a heated press roll (press roll having no heating function). The thickness of the single layer before stretching is 10 mu m, the unreeling speed is 5m/min, and the number of stretching rolls is 16. The temperature of the cold drawing roller is 80 ℃, the temperature of the hot drawing roller is 155 ℃, and the temperature of the setting roller is 162 ℃. The cold drawing press roller, the hot drawing press roller and the shaping press roller are rollers without heating function. The cold drawing multiplying power is 1.1, the hot drawing multiplying power is 1.9, and the setting multiplying power is 0.8. And layering the diaphragm after stretching to obtain the single-layer diaphragm. The interlayer air permeability value obtained by the test after the experiment is 110S.

The foregoing is a more detailed description of the present application in connection with specific embodiments thereof, and it is not intended that the present application be limited to the specific embodiments thereof. It will be apparent to those skilled in the art from this disclosure that many more simple derivations or substitutions can be made without departing from the inventive concepts herein.

Claims (10)

1. A production apparatus for a battery separator, comprising:

the extruder is used for melting and extruding the diaphragm raw material to obtain a base film;

the drying oven is used for carrying out annealing treatment on the base film;

the composite roller is used for compositing the multiple layers of base films subjected to annealing treatment to form a composite film;

and the stretching roller group, the stretching roller group includes cold drawing section, hot drawing section and design section for supply the complex film to loop through, with tensile complex film, and form the battery diaphragm, the cold drawing section includes first compression roller and cold drawing roller, first clearance that supplies the complex film to pass through has between first compression roller and cold drawing roller, the hot drawing section includes second compression roller and hot drawing roller, second compression roller and hot drawing roller have the second clearance that supplies the complex film to pass through, design section includes third compression roller and design roller, third compression roller and design roller have the third clearance that supplies the complex film to pass through between, at least one in first compression roller, second compression roller and the third compression roller adopts the warming mill, so that the positive and negative both sides of complex film are heated evenly.

2. The production equipment as claimed in claim 1, wherein the first press roll, the second press roll and the third press roll are heated rolls, the temperature of the first press roll is the same as that of the cold drawing roll, the temperature of the second press roll is the same as that of the hot drawing roll, and the temperature of the third press roll is the same as that of the sizing roll.

3. The production apparatus as claimed in claim 1, wherein the first press roll and the cold drawing roll are both at a temperature a, and a has a value in a range of: a is more than or equal to 40 and less than or equal to 90 ℃.

4. The production apparatus according to claim 1, wherein the second press roll and the hot drawing roll are both at a temperature b, and the value range of b is as follows: b is more than or equal to 130 and less than or equal to 155 ℃.

5. The production equipment of claim 1, wherein the temperatures of the third press roll and the sizing roll are both c, and the value range of c is as follows: c is more than or equal to 150 and less than or equal to 170 ℃.

6. The production apparatus according to any one of claims 1 to 5, wherein the number of layers of the composite film is d, and the value range of d is: d is more than or equal to 3 and less than or equal to 20 layers.

7. The production facility according to any of claims 1 to 5, wherein the draw unwinding speed of the draw roll set is e, and e is in the range of 2. ltoreq. e.ltoreq.10m/min.

8. The production facility of any of claims 1-5, wherein the membrane feedstock comprises at least one of polypropylene, polyethylene, polyacrylonitrile, and poly-4-methylpentene.

9. A production method of a battery separator, which is applied to the separator production apparatus according to any one of claims 1 to 8, comprising:

a casting extrusion step: fusing and extruding a diaphragm raw material, and then collecting a long-roll base film;

annealing and heat treatment: placing the wound base film into a baking oven for baking heat treatment;

compounding: compounding the annealed base films, and compounding the multiple base films together to form a composite film roll;

a stretching step: the method comprises the following steps of sequentially stretching a composite film through a cold-drawing section, a hot-drawing section and a shaping section to obtain a battery diaphragm, wherein in the cold-drawing section, the composite film passes through a first gap between a first pressing roller and a cold-drawing roller, in the hot-drawing section, the composite film passes through a second gap between a second pressing roller and a hot-drawing roller, in the shaping section, the composite film passes through a third gap between a third pressing roller and a shaping roller, and at least one of the first pressing roller, the second pressing roller and the third pressing roller adopts a heating roller so that the front side and the back side of the composite film are uniformly heated;

layering: and (3) layering the multilayer battery diaphragm prepared by stretching to obtain a single-layer battery diaphragm.

10. A battery separator manufactured using the separator production method of claim 9, having an interlayer transverse gas permeability range of f: f is more than or equal to 20 and less than or equal to 60S.

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