KR101895159B1 - Separator winding core, separator roll, and method of producing separator roll - Google Patents

Abstract

[PROBLEMS] To achieve a separator winding core which has a large frictional force between its sides and is hard to collapse even when piled up.
[MEANS FOR SOLVING PROBLEMS] There is provided a separator winding core characterized in that at least two of the side faces on which the separators are not wound are stacked in the vertical direction, and the arithmetic mean roughness of at least one side of the side faces is 0.16 탆 or more .

Description

TECHNICAL FIELD [0001] The present invention relates to a separator winding core, a separator winding body, and a method of manufacturing a separator winding core. [0002] SEPARATOR WINDING CORE, SEPARATOR ROLL, AND METHOD OF PRODUCING SEPARATOR ROLL [

The present invention relates to a separator winding core used for winding a separator for a non-aqueous electrolyte secondary battery, a separator winding wherein the separator is wound around a separator winding core, and a method for manufacturing the separator winding.

Patent Document 1 discloses a separator for a nonaqueous electrolyte secondary battery which is continuously transported by a conveying system such as a roller or the like and which comprises a separator winding core (hereinafter also referred to as "core") wound when the produced separator is supplied as a product ) Is exemplified.

The core disclosed in Patent Document 1 has an outer cylindrical member to which the separator is wound, an inner cylindrical member that functions as a bearing for holding the shaft, a support member (hereinafter also referred to as a " rib ") connected to the outer cylindrical member and the inner cylindrical member, And the produced separator is supplied as a wound body to the outer cylindrical member.

Japanese Patent Laid-Open Publication No. 2013-139340 (published on July 18, 2013)

When the outer peripheral surface of the core is damaged by contact with other cores, paper, or the like, it may cause damage to the separator wound on the outer peripheral surface of the core. Therefore, when storing the core, it is required to store the outer circumferential surface of the outer cylindrical member of the core so that the outer circumferential surface of the core does not come in contact with other cores or the ground.

As a method for storing the outer circumferential surface of the core so that the outer circumferential surface of the core is not in contact with other cores or paper surfaces, there is a method of stacking the cores so that the side faces of the cores are vertically oriented.

Further, the prepared separator is wound around the core and stored as a separator winding, whereby the separator can be stored. In this case, too, the separator winding width is narrower than the core width, so that the separator winding body is stacked and stored so that the side surface of the separator winding body is vertically oriented so as not to touch other cores, other separators, .

However, it is presumed that a shock or vibration occurs in the core, such as a human's hand colliding with a stacked core by mistake, or carrying a stacked core. In the above-described storage method, when the frictional force of the side surface of the core is small, a shock or a vibration is generated, and the core slips and the stacked core collapses. The same problem may occur even when the separator winding is stacked and stored.

In Patent Document 1, there is no description about the storage method of the core and the separator winding and the frictional force of the side, and the same problem is assumed.

An object of the present invention is to realize a separator winding core and a separator winding body which are easily handled by suppressing slippage or the like due to a large frictional force on a side surface.

In order to solve the above problems, a separator winding core according to the present invention is a separator winding core in which a separator for a non-aqueous electrolyte secondary battery is wound. In the separator winding core, at least one Plane has an arithmetic average roughness of 0.16 탆 or more. According to the above configuration, since the frictional force of the side surface is large, slippage and misalignment can be suppressed, and the separator winding core can be easily handled.

In the above configuration, the average value of the surface roughness may be 3 占 퐉 or less. According to the above arrangement, it is possible to provide a separator winding core capable of easily cleaning while maintaining the above-mentioned merits.

In the above configuration, the average value of the surface roughness may be 0.9 占 퐉 or less. According to the above configuration, it is possible to provide a separator winding core that can be cleaned more easily while maintaining the above-mentioned advantages.

In the above configuration, at least two of the separator winding cores may be stacked in the vertical direction. According to the above configuration, the separator winding cores can be stacked up and stored.

In the above constitution, as the material, any of ABS resin, polyethylene resin, polypropylene resin, polystyrene resin, polyester resin and vinyl chloride resin may be included. According to the above configuration, the separator winding core can be manufactured by resin molding using a metal mold.

The separator winding according to the present invention is characterized in that the separator is wound on the separator winding core. According to the above configuration, it is possible to provide a separator winding that is easy to store and a separator that is wound around the separator winding.

A method of manufacturing a separator winding according to the present invention is a method for manufacturing a separator winding wherein a separator for a non-aqueous electrolyte secondary battery is wound on a separator winding core, comprising a separator manufacturing step for manufacturing the separator, And a winding step of winding the separator on the separator winding core having an arithmetic mean roughness of at least 0.16 탆 on at least one side surface of the side surface of the separator not wound.

In the above production method, the arithmetic average roughness may be 3 mu m or less.

In the above production method, the arithmetic average roughness may be 0.9 탆 or less.

According to the present invention, it is possible to provide a separator winding core and a separator winding which are difficult to collapse even when they are stacked in the vertical direction, and are easy to handle during storage.

1 is a schematic diagram showing a sectional configuration of a lithium ion secondary battery.
Fig. 2 is a schematic view showing a state of each state of the lithium ion secondary battery shown in Fig. 1; Fig.
3 is a schematic diagram showing a state in each state of a lithium ion secondary battery having another structure.
4 is a schematic view showing a configuration of a slit apparatus for slitting a separator.
5 is a front view of a separator winding core according to an embodiment of the present invention and a separator winding body obtained by winding a separator around a separator winding core.
6 is a view showing an example of a method for storing a separator winding core according to an embodiment of the present invention.
7 is a view showing an example of a method of storing a separator winding core according to a reference embodiment;

Hereinafter, embodiments of the present invention will be described in detail with reference to Figs. 1 to 7. Fig. Hereinafter, a heat-resistant separator for a battery such as a lithium ion secondary battery will be described as an example of a separator film for a battery wound around a winding core (core) of a separator film according to the present invention.

≪ Configuration of Lithium Ion Secondary Battery >

First, a lithium ion secondary battery will be described with reference to Figs. 1 to 3. Fig.

BACKGROUND ART A non-aqueous electrolyte secondary battery typified by a lithium ion secondary battery has a high energy density and is presently used as a battery for devices such as personal computers, portable telephones, portable information terminals, mobile devices such as automobiles and airplanes, And is widely used as a static battery contributing to stable supply.

1 is a schematic diagram showing a sectional configuration of a lithium ion secondary battery 1.

1, the lithium ion secondary battery 1 includes a cathode 11, a separator 12, and an anode 13. The external device 2 is connected between the cathode 11 and the anode 13 at the outside of the lithium ion secondary battery 1. [ When the lithium ion secondary battery 1 is charged, electrons move in the direction A and in the direction B in the discharge.

<Separator>

The separator 12 is disposed between the cathode 11, which is the cathode of the lithium ion secondary battery 1, and the anode 13, which is a negative electrode thereof, so as to be sandwiched therebetween. The separator 12 separates the cathode 11 and the anode 13, and enables the movement of lithium ions therebetween. As the material of the separator 12, for example, a polyolefin such as polyethylene, polypropylene or the like is used.

2 is a schematic diagram showing a state of each state of the lithium ion secondary battery 1 shown in Fig. 2 (a) shows a normal state, (b) shows a state when the temperature of the lithium ion secondary battery 1 is raised, (c) shows a state when the lithium ion secondary battery 1 is rapidly heated .

As shown in Fig. 2 (a), the separator 12 has a plurality of holes P formed therein. Normally, the lithium ions 3 of the lithium ion secondary battery 1 can pass through the hole P.

Here, for example, the lithium ion secondary battery 1 may be heated up due to overcharge of the lithium ion secondary battery 1 or a large current caused by short-circuiting of external equipment. In this case, as shown in Fig. 2 (b), the separator 12 is melted or softened and the hole P is closed. Then, the separator 12 is contracted. As a result, the passage of the lithium ions 3 stops, so that the above-mentioned temperature rise also stops.

However, when the lithium ion secondary battery 1 is rapidly heated, the separator 12 shrinks abruptly. In this case, the separator 12 may be broken as shown in Fig. 2 (c). Since the lithium ions 3 leak from the broken separator 12, the migration of the lithium ions 3 does not stop. Thus, the temperature rise continues.

<Heat-resistant separator>

Fig. 3 is a schematic diagram showing a state in each state of the lithium ion secondary battery 1 of another constitution. Fig. 3 (a) shows a normal state, and Fig. 3 (b) shows a state when the lithium ion secondary battery 1 is rapidly heated.

As shown in FIG. 3A, the lithium ion secondary battery 1 may further include the heat resistant layer 4. The heat-resistant layer 4 can be formed on the separator 12. 3 (a) shows a structure in which a heat-resistant layer 4 as a functional layer is formed on the separator 12. As shown in Fig. Hereinafter, a film in which the heat resistant layer 4 is formed on the separator 12 is referred to as a heat resistant separator 12a as an example of a separator with a function layer. The separator 12 in the functional layer-attached separator is used as a base material for the functional layer.

3 (a), the heat-resistant layer 4 is laminated on one surface of the separator 12 on the cathode 11 side. The heat resistant layer 4 may be laminated on one side of the separator 12 on the anode 13 side or may be laminated on both sides of the separator 12. In the heat-resistant layer 4, a hole similar to the hole P is formed. Normally, the lithium ions 3 pass through the hole P and the hole of the heat resistant layer 4. The heat-resistant layer 4 includes, for example, a wholly aromatic polyamide (aramid resin) as a material thereof.

The heat resistant layer 4 assists the separator 12 even if the lithium ion secondary battery 1 is rapidly heated and the separator 12 is melted or softened as shown in FIG. 3 (b) , The shape of the separator 12 is maintained. Therefore, the separator 12 is melted or softened to cause the hole P to be closed. As a result, the passage of the lithium ions 3 stops, so that the overdischarge or overcharge is stopped. Thus, breakage of the separator 12 is suppressed.

&Lt; Manufacturing process of separator / heat-resistant separator >

The production of the separator and the heat-resistant separator of the lithium ion secondary battery 1 is not particularly limited, and can be carried out by a known method. Hereinafter, it is assumed that a porous film as a raw material of a separator (heat-resistant separator) mainly contains polyethylene as its material. However, even when the porous film contains other materials, a separator (heat-resistant separator) can be produced by the same manufacturing process.

For example, an inorganic filler or a plasticizer is added to a thermoplastic resin to form a film, and then the inorganic filler and the plasticizer are washed and removed with an appropriate solvent. For example, in the case of a polyolefin separator in which the porous film is formed of a polyethylene resin containing ultrahigh molecular weight polyethylene, it can be produced by the following method.

The method includes (1) a kneading step of kneading ultrahigh molecular weight polyethylene, an inorganic filler (e.g., calcium carbonate, silica) or a plasticizer (e.g., low molecular weight polyolefin, liquid paraffin) to obtain a polyethylene resin composition, (3) a step of removing the inorganic filler or plasticizer from the film obtained in the step (2); and (4) a step of stretching the film obtained in the step (3) Thereby obtaining a porous film. The step (4) may be performed between the steps (2) and (3).

Many fine holes are formed in the film by the removal process. The micropores of the film stretched by the stretching process become the above-mentioned hole P. [ Thereby, a porous film (separator 12) which is a polyethylene microporous membrane having a predetermined thickness and air permeability can be obtained.

In the kneading step, 100 parts by weight of ultrahigh molecular weight polyethylene, 5 to 200 parts by weight of a low molecular weight polyolefin having a weight average molecular weight of 10,000 or less, and 100 to 400 parts by weight of an inorganic filler may be kneaded.

Thereafter, in the coating step, the heat resistant layer 4 is formed on the surface of the porous film. For example, an aramid / NMP (N-methyl-pyrrolidone) solution (coating solution) is applied to a porous film to form a heat resistant layer 4 which is an aramid heat resistant layer. The heat-resistant layer 4 may be formed on only one side of the porous film or on both sides of the porous film. As the heat-resistant layer 4, a mixed solution containing a filler such as alumina / carboxymethylcellulose may be coated.

Further, in the coating step, an adhesive layer is formed on the surface of the porous film by applying (coating) a polyvinylidene fluoride / dimethylacetamide solution (coating solution) to the surface of the porous film and precipitating it (precipitation step) It is possible. The adhesive layer may be formed on only one side of the porous film or on both sides of the porous film.

The method of coating the coating liquid on the porous film is not particularly limited as long as it can uniformly wet-coat the coating liquid, and conventionally known methods can be employed. For example, a coating method such as a capillary coating method, a spin coating method, a slit die coating method, a spray coating method, a dip coating method, a roll coating method, a screen printing method, a flexo printing method, a bar coater method, And the like. The thickness of the heat resistant layer 4 can be controlled by the thickness of the coating wet film and the solid content concentration in the coating liquid.

As the support for fixing or conveying the polyolefin-based porous film at the time of coating, a resin film, a metal belt, a drum, or the like can be used.

As described above, the separator 12 (heat-resistant separator) in which the heat resistant layer 4 is laminated on the porous film can be produced. The fabricated separator is wound around a cylindrical core. In addition, the object to be produced by the above production method is not limited to the heat resistant separator. This manufacturing method does not need to include a coating process. In this case, the object to be produced is a separator having no heat resistant layer.

<Slit device>

(Hereinafter referred to as &quot; separator &quot;) having no heat resistant separator or heat resistant layer is preferably a width (hereinafter, referred to as &quot; product width &quot;) suitable for applications such as the lithium ion secondary battery 1 and the like. However, in order to increase the productivity, the separator is manufactured such that its width is equal to or greater than the product width. And, once manufactured, the separator is cut (slit) into a product width.

The &quot; width of the separator &quot; means the length of the separator in parallel with the plane in which the separator extends and perpendicular to the longitudinal direction of the separator. Hereinafter, a separator having a wide width before slitting will be referred to as a &quot; fabric &quot;, and a slit separator will be specifically referred to as a &quot; slit separator &quot;. The slit means that the separator is cut along the longitudinal direction (the film flow direction in the production, MD: Machine direction), and the cut means that the separator is cut along the transverse direction (TD) it means. The transverse direction (TD) means a direction which is parallel to the plane in which the separator extends, and is substantially perpendicular to the longitudinal direction (MD) of the separator.

Fig. 4 is a schematic diagram showing the configuration of a slit apparatus 6 for slitting a separator. Fig. 4 (a) shows the overall configuration, and Fig. 4 (b) shows the configuration before and after slitting the fabric.

4A, the slit apparatus 6 is constituted by a cylindrical roller 61, rollers 62 to 69, and a plurality of winding rollers 70U, 70L .

<Slit Before>

In the slit apparatus 6, a cylindrical core c wound with a raw fabric is sandwiched between the take-up rollers 61. As shown in Figure 4 (b), the fabric is unwound from the core c in the path U or L. The unwound fabric is conveyed to the roller 68 via the rollers 63 to 67. [ In the process of being transported, the fabric is slit into a plurality of separators. Further, in order to transport the fabric to a desired trajectory, the number and arrangement of the rollers 62 to 69 may be changed.

<After the slit>

As shown in Fig. 4 (b), a part of the plurality of slit separators is wound around each of the cylindrical cores u fitted in the winding rollers 70U. Further, another part of the plurality of slit separators is wound around each cylindrical core 1 (separator winding core) sandwiched by the winding roller 70L. The slit separator wound in the form of a roll and the integral body of the core u · 1 are referred to as "a winding (separator winding)".

<Separator Winding Core and Separator Winding Member>

Fig. 5 is a front view of a winding body in which a core and a core are wound with a separator.

The separator 12 is wound around the inner cylindrical member 102 of the core 100 shown in Figure 5 (a) with the shaft of a winding roller or the like interposed therebetween while rotating the core 100, , The winding body 110 shown in Fig. 5 (b) can be manufactured.

The core 100 described above can be applied to the cores u and l of the slit device 4 shown in Fig. 4, for example. That is, the winding of the separator 12 using the core 100 can be performed in the same manner as the above-described method.

<Core Structure>

The core 100 shown in Fig. 5 (a) has an outer cylindrical member 101, an inner cylindrical member 102, and a plurality of ribs 103. As shown in Fig. The outer cylindrical member 101 defines the outer peripheral surface of the core 100 on which the separator 12 is wound. The inner cylindrical member 102 is provided on the inner side of the outer cylindrical member 101 and functions as a bearing to which a shaft such as a winding roller for rotating the core is fitted. The rib 103 is a support member extending in the radial direction between the outer cylindrical member 101 and the inner cylindrical member 102 and connected to both.

In this embodiment, the ribs 103 are arranged so as to be perpendicular to the outer cylindrical member 101 and the inner cylindrical member 102 at positions spaced equally from each other and divided into eight equal parts. However, the number of ribs and the spacing of the ribs are not limited to this.

It is preferable that the centers of the circumferences of the outer cylindrical member 101 and the inner cylindrical member 102 coincide with each other, but the present invention is not limited thereto. The thicknesses of the outer cylindrical member 101 and the inner cylindrical member 102 and the dimensions such as the width and radius of the outer peripheral surface can be appropriately designed according to the type of the separator to be manufactured and the like.

The mass of the core 100 is usually 250 g to 800 g.

The area of the side surface of the core 100 on which the separator 12 is not wound is usually 10 cm 2 to 80 cm 2.

Further, the mass of the rolled body 110 is usually 400 g to 6000 g.

As the material of the core 100, resins including any of ABS resin, polyethylene resin, polypropylene resin, polystyrene resin, polyester resin and vinyl chloride resin can be suitably employed. As a result, the core 100 can be manufactured by resin molding using a metal mold.

<Stacking core>

6 is a view showing a state in which the core 100 is stacked.

If the outer peripheral surface of the outer cylindrical member 101 on which the separator 12 is wound is scratched due to contact with the ground or the like, the separator 12 wound by the scratches may be damaged. Further, foreign matter may be deposited on the scratches, and foreign matter deposited on the wound separator 12 may adhere to the separator 12, which may cause the separator 12 to become defective.

Therefore, when storing the core, it is required that the outer peripheral surface of the outer cylindrical member 101 is not brought into contact with the ground or the like as much as possible.

As shown in FIG. 6, a plurality of cores 100 are piled up and stored by vertically arranging the side where the separator 12 of the core 100 is not wound, so that the outer peripheral surface of the outer cylindrical member 101 is brought into contact with the ground And storage can be performed.

Although three cores 100 are stacked in Fig. 6, at least two stacks can be stacked. It is also possible to stack and store more than four cores.

However, it is conceivable that a person or an object is erroneously brought into contact with the stacked core 100 during actual storage. It is also assumed that vibration occurs in the core 100 when the stacked cores 100 are combined and transported.

When the stacked core 100 is impacted or vibrated, if the frictional force between the side surfaces of the stacked core 100 is small, the core 100 largely deviates, Can be thought of as collapsing.

&Lt; Fixing method of core &

As an example of a method of fixing the stacked core 100 so that it does not collapse, there is a method in which, as shown in Fig. 7 (a), in the center of the plane of the cylinder, ) Can be used.

The diameter of the shaft of the base sheet 120 is slightly smaller than the inner diameter of the inner cylindrical member 102 of the core 100. The core 100 can be fixed by stacking the core 100 on the shaft of the base sheet 120 through the hole of the inner cylindrical member 102 of the core 100 as shown in Figure 7 (b) have.

However, in the case of storing the core 100 using the die sheet 120, when the core 100 is stacked on the die sheet, the core 100 may be moved from the upper side to the lower side of the die sheet 120 There is a need. Conversely, even when the core 100 is taken out from the base sheet 120, it is necessary to move the core 100 from below the axis of the base sheet 120 to the top. This causes time and effort for handling the core 100, which causes inefficiency of the operation.

When the core 100 is stacked on the die sheet 120 or taken out from the die sheet 120, the axis of the die seat 120 and the inner circumferential surface of the inner cylindrical member 102 may rub against each other . As a result, the inner cylindrical member 102 is also scratched, foreign matter or the like is deposited on the scratched and adhered to the separator 12, which may cause the separator 12 to become defective.

<Side surface roughness>

From the above-described problems, it is required to prevent a deviation of the stacked core 100 without requiring a fastener such as the base sheet 120. As a method for solving this problem, a method of improving the frictional force of the side surface of the core 100 and reducing the deviation of the cores 100 can be considered.

When the frictional force between the side surfaces of the core 100 is sufficiently large, even if a certain degree of external force is generated in the stacked core 100, the core 100 is not displaced, .

The inventor has paid attention to improving the surface roughness of the side surface of the core 100 as a method of improving the frictional force between the cores 100. [

As a reference of the surface roughness, for example, an arithmetic average roughness indicating a size per unit area of an absolute value of the size of the irregularities of the surface based on the average height of the surface can be adopted. The frictional force between the surfaces having large arithmetic mean roughness tends to be large. However, if the arithmetic average roughness is too large, the point contact becomes close to point contact, so that it may be rather small. Therefore, from the viewpoint of improving the frictional force of the side surface of the core 100, the arithmetic average roughness of the side surface of the core 100 is preferably 10 占 퐉 or less, more preferably 3 占 퐉 or less.

It is more preferable that the arithmetic average roughness on the side surface of the core 100 is within the above-mentioned range on both sides of the core 100. [

The arithmetic mean roughness of the side surface of the core 100 can be adjusted by roughening the surface of the separator take-up core by blast treatment or by smoothing it by polishing or the like. The arithmetic average roughness of the side surface of the core 100 may be adjusted by machining a metal mold used for manufacturing the separator winding core.

<Ease of cleaning>

However, the surface having a very high arithmetic average roughness has a problem that cleaning is difficult when minute foreign matters adhere.

The core 100 can be reused by cleaning the core 100 and winding the new separator 12 after the separator 12 has been unwound from the winding body 110 in the battery manufacturing process. It is necessary to remove foreign substances adhering to the core 100 during the cleaning. This is to prevent the foreign matter remaining in the core 100 from adhering to the separator 12, thereby causing defects.

At this time, if the side surface of the core 100 has a larger average roughness than necessary, foreign matter can not be sufficiently removed in the cleaning process, and there is a fear that the core 100 can not be reused. In addition, even if foreign matter can be removed, if washing takes a long time, there arises a problem that the process for reuse is prolonged.

From the above, the inventor has found that the side surface of the core 100 is required to have a proper surface roughness in order to combine both frictional force between the side surfaces and ease of cleaning.

When the side surface illuminance of the core 100 is in the above range, even when the winding body 110 wound with the separator 12 is wound on the core 100, when the winding body 110 is piled up, It is advantageous in that it is difficult to shift. In order to exhibit the above effect, the separator 12 having a width narrower than the thickness direction length of the core 100 having the side roughness in the above range may be wound around the core 100 to form the winding body 110.

The core 100 may be protruded from at least one side of the side surface of the separator 12 wound around the core 100 in the winding body 110. The length of the core 100 protruding from the side surface of the wound separator 12 is preferably 1 mm or more from the viewpoint of preventing the separator 12 from being damaged.

&Lt; Measurement test of core &

Based on the above, the inventor has conducted an experiment to verify the frictional force and easiness of cleaning the core 100 having different surface roughness.

First, a plurality of cores A having the same shape as that of the core 100 were prepared, and the arithmetic average roughness of the side was measured. The constitution and physical properties of the plurality of cores A are substantially the same.

Specifically, the arithmetic average roughness of each side of the plurality of cores A was measured. As a surface roughness measurement device, &quot; Handysurf E-35A &quot; (manufactured by Tokyo Seimitsu Kabushiki Kaisha) was used. The tip of the measuring head is 60 ° cone. The tip radius of the stylus tip is 2 탆. In the present embodiment, the measuring force of the surface roughness measuring apparatus was set to 0.75 mN, the measuring speed to 0.5 mm / s, the evaluation length to 4.0 mm, and the cutoff value to 0.8 mm. Since the roughness of the side surface of the core 100 can be regarded as being approximately uniform, the average value of the arithmetic average roughness measured for the ten different side surfaces is taken as the arithmetic average roughness on the side of the core.

Next, an experiment was conducted to measure the frictional force of the side surface of the core A.

Initially, as shown in Fig. 5 (a), an outer cylinder having an outer diameter of 6 inches, an inner cylinder member having an inner diameter of 3 inches, a thickness of 65 mm, A separator 12 having a width of 60 mm was wound on the outer peripheral surface of the outer cylindrical member 101 of the core A having a side surface area of 41 cm 2 and a weight of 0.36 kg to the central portion of the outer peripheral surface of the core A, A was produced. Subsequently, two wound bodies A, which were formed on a horizontal bogie carrying a non-slip rubber mat, were piled up so that the core A overlapped with each other in a plan view. After that, the vehicle was transported on a flat road at a constant speed of 30 m / min for 5 m, and then it was suddenly stopped.

The largest deviation among the deviations of the winding bodies A caused by the stopping paper was measured and the frictional force was evaluated. The evaluation was evaluated as? If the deviation was less than 2 mm,? If the deviation was not less than 2 mm and not more than 5 mm, and? If the deviation was not less than 5 mm.

Finally, an experiment was conducted to verify the cleaning easiness of the side surface of the core A.

Acetylene black particles were sprayed on the side surface of the core A and rubbed with a nonwoven fabric of pulp to adhere black stain. The black contamination is assumed to be a positive electrode material or a negative electrode material of a battery having conductivity, which can be considered to be attached to the core 100 in a battery manufacturing process.

This was rubbed with a nonwoven fabric having ethanol attached thereto, and it was confirmed by eyes and repeatedly confirmed whether or not the black contamination could be removed.

The cleaning easiness on the side surface of the core A was evaluated according to the number of times of the above cleaning. The evaluation was evaluated as &amp; cir &amp; if the contamination could be removed within 3 times, &amp; cir &amp; if it could not be removed within 3 times but removed within 5 times, and &amp;

<Experimental Results>

As in the case of the core A, the cores B to G having different side surface roughnesses were also subjected to the same tests. The cores B to G also have the same shape as the core 100. Table 1 below shows the evaluation results of experiments performed on cores A to G, respectively.

In Table 1, the column of "arithmetic average roughness (m)" represents the arithmetic mean roughness on each side measured for cores A to G. The terms "frictional force" and "ease of cleaning" indicate evaluation of frictional force and evaluation of ease of cleaning for cores A to G, respectively.

&Lt; Evaluation of core &

Experimental results of the core A show that when the arithmetic average roughness of the side surface of the core 100 is 0.15 탆 or less, the frictional force of the side surface of the rolled body 110, in which the separator 12 is wound around the core 100, have. This suggests that there is a high possibility that the winding body 110 being stored is likely to fall down by largely shifting the piled winding body 110.

Experimental results of the core F and the core G show that when the arithmetic average roughness of the side surface of the core 100 is 1 탆 or more, it is difficult to clean the core 100. Therefore, ) Is likely to be the cause of defects.

On the other hand, the core B and the core E both suitably adopted as the actual core 100 because they have both the frictional force and the ease of cleaning both to some extent. Further, the core C and the core D have excellent physical properties both in terms of frictional force and easiness of cleaning, and show that they are very suitable for an actual core 100. [

<Summary>

Based on the above experimental results, it can be assumed that the winding body 110 is preferably wound on the core 100 having an arithmetic mean roughness of at least 0.16 탆 or more on the side surface. With the above-described configuration, it is possible to realize the winding body 110 which is difficult to collapse even if piled up and stored. At this time, it is possible to easily store not only the core 100 but also the wound separator 12 without contacting the ground or the like, by stacking and holding the winding body 110.

For the same reason, it is preferable that the arithmetic average roughness of the core 100 is at least 0.16 탆 or more. According to the above configuration, even when the core 100, in which the separator 12 is not wound, is stored as a unit, the core 100 that is difficult to collapse even when piled up can be realized.

In the case where two cores 100 are stacked and stored, the arithmetic average roughness on the side surface of the core 100 may be within the preferable range described above with respect to either surface. At this time, the surfaces of the cores 100 having the arithmetic mean roughness within the preferable range described above are brought into contact with each other to stack the cores 100, so that the slippage between the cores 100 is reduced so that the two cores 100 can be stacked and stored It becomes.

When both side surfaces of the core 100 are within the above-described preferable ranges, it is easy to stack three or more cores 100 and store them. In addition, since the frictional force with the ground on which the core 100 is provided is increased during storage, slippage can be prevented, and the collapsed core 100 can be prevented more efficiently.

In addition, it is preferable that the arithmetic average roughness of the side surface of the core 100 is at least 0.9 탆 or less. According to the above configuration, it is possible to provide the core 100 that can be easily cleaned. The winding body 110 formed by winding the core 100 with the separator 12 is preferable in that cleaning after use is facilitated.

The present invention is not limited to the above-described embodiments, and various modifications may be made within the scope of the claims, and embodiments obtained by appropriately combining the technical means disclosed in the different embodiments may be included in the technical scope of the present invention. do.

1: Lithium ion secondary battery
2: External device
3: Lithium ion
4: Heat resistant layer
11: Cathode
12: Separator
12a: Heat-resistant separator
13: anode
100: Core
110: winding
120:

Claims (10)

A separator winding core for use in a method for stacking at least two separator winding cores, in which a side surface which is a non-wound surface of a separator winding core wound around a separator for a non-aqueous electrolyte secondary battery is vertically oriented, ,
Wherein an arithmetic mean roughness of at least one surface of the side surface is 0.16 탆 or more and 0.9 탆 or less,
The material of the separator winding core includes any of ABS resin, polyethylene resin, polypropylene resin, polystyrene resin, polyester resin and vinyl chloride resin,
Wherein the core has a mass of 250 g to 800 g. delete A separator winding wherein the separator is wound on the separator winding core according to claim 1. The separator winding according to claim 3, wherein a width of the separator winding core is larger than a width of the separator. A separator winding method in which a separator for a non-aqueous electrolyte secondary battery is wound on a separator winding core,
A separator manufacturing step of manufacturing the separator,
A separator winding core for use in a method for stacking at least two separator winding cores that do not require the use of fixing members so that the side surface of the separator winding core wound around the separator for the nonaqueous electrolyte secondary battery is a non- Wherein an arithmetic average roughness of at least one surface of the side surface of the separator is not more than 0.16 탆 and not more than 0.9 탆,
Wherein the separator winding core comprises a material selected from the group consisting of an ABS resin, a polyethylene resin, a polypropylene resin, a polystyrene resin, a polyester resin and a vinyl chloride resin, And a step of winding the separator. delete delete delete delete delete

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