KR102142427B1 - Separator winding core, separator roll, and method of cleaning separator winding core - Google Patents

Abstract

It shortens the process time required for the reuse of the separator winding core. As a separator winding core in which a separator for a nonaqueous electrolyte secondary battery is wound, in a Munsell color system, brightness is 3.0 or more and 9.2 or less, and saturation is 0.5 or more.

Description

Cleaning method of separator winding core, separator winding body, and separator winding core {SEPARATOR WINDING CORE, SEPARATOR ROLL, AND METHOD OF CLEANING SEPARATOR WINDING CORE}

The present invention relates to a separator winding core in which a separator for a non-aqueous electrolyte secondary battery is wound, a separator winding body provided with the separator winding core, and a cleaning method for the separator winding core.

Non-aqueous electrolyte secondary batteries such as lithium ion secondary batteries are widely used as batteries used in personal computers, mobile phones, portable information terminals, and the like. In particular, the lithium ion secondary battery has attracted attention as a battery that reduces the amount of CO ₂ emitted and contributes to energy saving compared to the conventional secondary battery.

The development of a separator winding core in which a separator (film) for a nonaqueous electrolyte secondary battery is wound has been conventionally performed (see Patent Document 1).

Japanese Patent Application Publication "Special Publication No. 2013-139340 (published on July 18, 2013)"

In recent years, it is considered to reuse the separator winding core after using the separator winding body in which the separator for a nonaqueous electrolyte secondary battery is wound with respect to the separator winding core. This is because the separator winding core is relatively expensive.

The steps required for reuse of the separator winding core include (a) to (d) below. That is, step (a) is a step of confirming that there is no crack or distortion in the separator winding core based on the limit sample. Step (b) is a step of peeling off the label when a label is attached to the separator winding core. Step (c) is a step of removing contamination of the winding surface, inner surface and ribs of the separator winding core. Step (d) is a step of inspecting that the separator winding core is sufficiently decontaminated so that it can be reused. In particular, the step (d) needs to be sufficiently high-precision in order to prevent contamination of foreign substances into the product when the next separator winding core is reused and to reduce the possibility of defective products occurring in the non-aqueous electrolyte secondary battery.

Here, in order to shorten the time of the step (d), contamination with a black conductive material (acetylene black, graphite, etc.) remaining in the separator winding core, or contamination with a white material (dust, separator debris, etc.) Needs to be discovered quickly. Here, the separator debris refers to a piece of a polyolefin porous film or an inorganic filler or the like that has been removed from a functional layer laminated on a polyolefin porous film. However, in the technique disclosed in Patent Literature 1, it is not considered to quickly find these contaminations.

This invention is made|formed in view of the said subject, The objective is a separator winding core which can shorten the process time required for reuse of a separator winding core, the separator winding body provided with this separator winding core, and the separator winding core. It is to provide a cleaning method.

In order to solve the above problems, the separator winding core according to one embodiment of the present invention is a separator winding core in which a separator for a non-aqueous electrolyte secondary battery is wound, and has a brightness of 3.0 or more and 9.2 or less and a saturation of 0.5 or more in a Munsell colorimeter.

According to the above structure, the separator winding core of the present invention is a color in which the black conductive substance or white substance attached to itself is sufficiently prominent, and therefore, when the black conductive substance or white substance adheres as contamination, this contamination It is easy to find them quickly. Therefore, according to the said structure, it becomes possible to shorten the inspection process time required for reuse of a separator winding core. In addition, it is common practice to use a color sample for color determination of the separator winding core.

According to the present invention, it becomes possible to shorten the inspection process time required for reuse of the separator winding core.

1 is a side view showing a schematic configuration of a separator wound body of the present invention.

1 is a side view showing a schematic configuration of a separator wound body 100. The separator winding body 100 includes a separator winding core 101 and a separator 102 for a nonaqueous electrolyte secondary battery wound around the separator winding core 101.

The separator 102 for a nonaqueous electrolyte secondary battery is disposed in the nonaqueous electrolyte secondary battery so as to be held between them between the positive electrode and the negative electrode. Here, a lithium ion secondary battery is assumed as the nonaqueous electrolyte secondary battery. The separator 102 for a non-aqueous electrolyte secondary battery is a porous film that enables movement of lithium ions between them while separating between a positive electrode and a negative electrode. The separator 102 for a non-aqueous electrolyte secondary battery contains, for example, polyolefin such as polyethylene and polypropylene.

The separator winding core 101 is a non-aqueous electrolyte secondary battery separator 102 wound, and is also called a core. The separator winding core 101 is made of ABS resin, for example.

In addition, in the color of the separator winding core 101, the Munsell colorimeter has a value of 3.0 or more and 9.2 or less, and a saturation (Chroma) of 0.5 or more. More preferably, the brightness of the separator winding core 101 is 4.0 or more and 9.0 or less. Thereby, the separator winding core 101 is a sufficiently prominent color of the black conductive material or white material attached to itself, and therefore, when the black conductive material or white material is attached as contamination, the contamination can be quickly It is easy to find. Therefore, the inspection process time required for the reuse of the separator winding core 101 can be shortened compared to the process time required for the reuse of the conventional separator winding core.

On the other hand, if the color of the separator winding core is 3.0 to 9.2 or less in the Munsell colorimeter, or saturation is not 0.5 or more, contamination or scratches caused by the black conductive material or white material may be observed by eye or optical inspection. It becomes difficult to discriminate. As a result, mixing of foreign matter is caused, and a defective product is generated in the nonaqueous electrolyte secondary battery, which is not preferable.

The cleaning method of the separator winding core 101 is a cleaning method of the separator winding core 101 that winds the separator 102 for a non-aqueous electrolyte secondary battery on an outer circumferential surface, and removes foreign substances attached to the surface of the separator winding core 101. It includes a foreign matter removal process and a process of inspecting whether the amount of foreign matter adhered to the surface of the separator winding core 101 is below a standard.

In addition, the separator wound body 100 is formed by winding a separator 102 for a nonaqueous electrolyte secondary battery on an outer circumferential surface of the separator winding core 101 that has been subjected to the cleaning method.

According to the said structure, the manufacturing cost of the separator wound body 100 can be reduced by recycling the relatively expensive separator winding core 101. Moreover, according to the said structure, it becomes possible to reduce the waste amount of the separator winding core 101, and to contribute to environmental conservation.

The separator winding core according to Embodiment 1 of the present invention is a separator winding core in which a separator for a nonaqueous electrolyte secondary battery is wound, and has a brightness of 3.0 or more and 9.2 or less and a saturation of 0.5 or more in a Munsell color system.

According to the above structure, the separator winding core of the present invention is a color in which the black conductive substance or white substance attached to itself is sufficiently prominent, and therefore, when the black conductive substance or white substance adheres as contamination, this contamination It is easy to find them quickly. Therefore, according to the said structure, it becomes possible to shorten the inspection process time required for reuse of a separator winding core. In addition, it is common practice to use a color sample for color determination of the separator winding core.

Moreover, it is preferable that the separator winding core which concerns on the form 2 of this invention is 4.0 or more and 9.0 or less especially.

Moreover, it is preferable that the separator winding core which concerns on Embodiment 3 of this invention has a surface with a glossiness of 10 or more and 130 or less.

Moreover, it is preferable that the glossiness of the said surface is 20 or more and 100 or less especially in the separator winding core which concerns on the form 4 of this invention.

When the glossiness (glossy unit; GU) measured by a measurement method standardized in ISO2813 is less than 10, there is no surface gloss and there is a high possibility that a black conductive material is hard to be found, or contamination is likely to adhere. It is also undesirable in that respect. When the glossiness is greater than 130, the light reflection becomes strong, and there is a high possibility that it becomes difficult to find contamination of a black conductive material or a white material. Therefore, the glossiness of the surface of the separator winding core is preferably 10 or more and 130 or less, more preferably 20 or more and 100 or less.

Moreover, it is preferable that the separator winding core which concerns on the form 5 of this invention contains the side surface of the said separator winding core as said surface.

If it is a separator winding core having the above glossiness, it becomes easier to quickly find contamination. Such contamination usually adheres to the outer circumferential surface of the separator winding core, which is wound on the surface, but tends to stick more to the side surface. Therefore, the glossiness may be provided on the outer circumferential surface, but it is more preferable to have it on the side surface.

The glossiness of the separator winding core can be adjusted, for example, by roughening the surface of the separator winding core, or smoothing it by polishing or the like. Further, the mold itself for manufacturing the separator winding core may be processed to adjust the glossiness.

In addition, the separator wound body according to the sixth aspect of the present invention includes any of the separator winding cores of the first to fifth embodiments, and a separator for a nonaqueous electrolyte secondary battery wound around the separator winding core.

According to the said structure, the separator wound body obtained by the same effect as the separator winding core of this invention can be realized.

Moreover, the cleaning method of the separator winding core which concerns on the form 7 of this invention is a cleaning method of any separator winding core in the said forms 1-5, The foreign material removal process which removes the foreign material adhering to the surface of the separator winding core, And a step of inspecting whether the amount of foreign matter attached to the surface of the separator winding core is below a standard.

In addition, the separator wound body according to the eighth aspect of the present invention is formed by winding the separator for a nonaqueous electrolyte secondary battery on the outer peripheral surface of the separator take-up core that has subjected the cleaning method of the seventh aspect.

According to the said structure, the manufacturing cost of a separator wound body can be reduced by recycling a relatively expensive separator winding core. Moreover, according to the said structure, it becomes possible to contribute to environmental conservation by reducing the waste amount of a separator winding core.

The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the claims, and embodiments obtained by appropriately combining the technical means disclosed in the other embodiments are also included in the technical scope of the present invention.

[Example]

An experiment was conducted to verify the effect of the separator winding core of the present invention, and details of the experiment will be described below.

First, as a material that mimics contamination attached to the separator winding core, first and second contamination samples were prepared.

The first contamination sample was prepared as follows. That is, acetylene black (trade name: Denka Black HS100: manufactured by Denka Corporation) 0.25g, PVDF (polyvinylidene fluoride resin) #1120 (Kurehaze, 12% by weight NMP solution of solid content) 1.15g, NMP (N-methyl -2-pyrrolidone) 1.00 g was stirred and mixed until uniform to prepare a first coating material having a solid content concentration of 16%. The produced first paint was coated on a 1 mm thick glass plate with a clearance of 50 μm using a coating bar, and then dried at 80° C. to prepare a first contamination sample. The weight per unit area of contamination calculated from the change in weight before application and after application and drying was 6.3 g/m ² .

The second contamination sample was prepared as follows. That is, acetylene black (trade name: Denka Black HS100: manufactured by Denka Corporation) 0.25g, PVDF #1120 (Kurehaze, 12% by weight NMP solution of solid content) 1.02g, NMP 7.49g was stirred and mixed until uniform, A second coating material having a solid content concentration of 4% was produced. The produced second coating material was coated on a 1 mm thick glass plate with a clearance of 50 μm using a coating bar, and then dried at 80° C. to prepare a second contamination sample. The weight per unit area of contamination calculated from the change in weight before application and after application and drying was 3.5 g/m ² .

Subsequently, for each color shown in Examples 1 to 13 and Comparative Examples 1 to 7, the first staining sample and the second on the standard color for H version paint in 2015 (pocket version, Japan Paint Industry Association of Japan) Contamination samples were placed, and visual comparison was performed under an illuminance of 300 lux or higher using an Hf fluorescent lamp (FHF32EX-NK) manufactured by HITACHI, and visibility was confirmed by the following criteria.

Good visibility (clear presence of contamination): ○

Visibility possible (it can be seen by looking closely at the existence of contamination): △

Poor visibility (difficult to determine the presence of contamination): ×

In addition, as a white foreign material, α Alumina (registered trademark) manufactured by Sumitomo Chemical Co., Ltd. (trade name: AKP3000) was used. Then, for each color shown in Examples 1 to 13 and Comparative Examples 1 to 7, 5 mg of the above-mentioned white foreign substance was placed on a standard color for H-plate paint in 2015 (pocket plate, Japan Paint Industry Association of Japan) By using HITACHI Hf fluorescent lamps (FHF32EX-NK), visual comparison was performed under an illuminance of 300 lux or higher, and visibility was confirmed based on the following criteria.

Good visibility (clear presence of white foreign objects): ○

Visibility possible (you can see it by looking closely at the presence of a white object): △

Poor visibility (difficult to discriminate the presence of white matter): ×

Table 1 shows the results of confirming the above visibility. In Table 1, items ``first contaminated sample (high weight per unit area)'', items ``second contaminated sample (low weight per unit area)'', and item ``white foreign matter'' respectively show the results of visibility corresponding to the notation of the above items. have.

Subsequently, a contaminated core was prepared in which contamination was adhered to the separator winding core.

The first contaminating core was prepared as follows. Initially, an ABS resin core having an outer diameter of 6 inches (15.24 cm), a hue (Hue) of 10B, a brightness of 5, and a saturation of 10 having the gloss of Table 2 was prepared. ABS resin cores having different gloss levels are shown in Table 2, respectively, as Example 6 (same color as Example 6 in Table 1), Examples 14 to 16, and Comparative Examples 8 and 9. Subsequently, a first contaminating core was produced in the same manner as the first contaminating specimen, except that the first coating was applied to each of the ABS resin cores. The weight per unit area of contamination calculated from the change in weight before application and after application and drying was 6.3 g/m ² . For each of the first contaminated cores, as a result of visually confirming the contaminants based on the judgment criteria already described, the items in Table 2 were the same as the "first contaminated core (high weight per unit area)". In addition, the glossiness was measured using a gloss meter Novo-Curve (manufactured by Rhopoint Instruments, corresponding standard; ISO2813, measuring range 0-1000GU, resolution 0.1GU), and Rounded to the first decimal place (incident angle 60°).

The second contaminating core was prepared as follows. That is, a second contaminating core was produced in the same manner as the second contaminating specimen, except that the second coating material was applied to each of the ABS resin cores. The weight per unit area of contamination calculated from the change in weight before application and after application and drying was 3.5 g/m ² . For each second contaminating core, as a result of confirming contaminants visually according to the judgment criteria already described, it was as in the item "Second contaminating core (low weight per unit area)" in Table 2. In addition, the glossiness was measured using a gloss meter novo-curve (manufactured by Low Point Instruments, corresponding standard; ISO2813, measurement range 0-1000GU, resolution 0.1GU), and the first decimal place of the measured value was rounded (incident angle 60). °).

In addition, as a white foreign material, α Alumina (registered trademark) manufactured by Sumitomo Chemical Co., Ltd. (trade name: AKP3000) was used. Then, 5 mg of the white foreign substance was placed on each of the ABS resin cores, and visual comparison was performed under the same environment as described above, and visibility was confirmed based on the criteria already described. It was the same.

From the results of the above experiments, it was found that the color of the separator winding core is more effective in that the brightness is 3.0 or more and 9.2 or less, the saturation is 0.5 or more, and the brightness is 4.0 or more and 9.0 or less in the Munsell colorimeter. In addition, it was found that the separator winding core satisfies the above-mentioned brightness and saturation, and that glossiness of 10 or more and 130 or less is more effective, and more preferably 20 or more and 100 or less.

100 separator winding body (film winding body)
101 separator winding core (film winding core)
102 Non-aqueous electrolyte separator for secondary batteries (film)

Claims (8)

As a separator winding core that can be reused, a separator for a non-aqueous electrolyte secondary battery is wound,
For visibility, in a Munsell colorimeter, a separator winding core having a brightness of 4.0 or more and 9.2 or less and a saturation of 0.5 or more. The separator winding core according to claim 1, wherein the brightness is 4.0 or more and 9.0 or less. The separator winding core according to claim 1, which has a surface having a glossiness of 10 or more and 130 or less. The separator winding core according to claim 3, wherein the surface has a gloss of 20 or more and 100 or less. The separator winding core according to claim 3, comprising a side surface of the separator winding core as the surface. The separator winding core according to any one of claims 1 to 5,
A separator winding body comprising a separator for a non-aqueous electrolyte secondary battery wound on the separator winding core. A method for cleaning the separator winding core according to any one of claims 1 to 5,
Foreign matter removal process for removing foreign matter attached to the surface of the separator winding core,
And a step of inspecting whether the amount of foreign matter adhered to the surface of the separator winding core is below a standard. A separator winding body comprising the separator for a nonaqueous electrolyte secondary battery wound on an outer circumferential surface of the separator winding core which has carried out the cleaning method according to claim 7.

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