Label for identifying defective portion of electrode for secondary battery capable of identifying both sides and method for manufacturing the same

Abstract

The present invention relates to a label for recognizing a defective portion of an electrode for a secondary battery and a method of manufacturing the same, and more particularly, to a label for recognizing a defective portion of an electrode for a secondary battery, in which a sensor can recognize both a front surface side and a back surface side of the label, and even if a sensor is installed at different positions for each production line, a defective portion of an electrode for a secondary battery can be easily recognized. The present invention is advantageous in that, in the case where device components of a production line for producing an electrode for a secondary battery are not fixed but different from each other, a defective portion can be easily recognized regardless of whether a position of a sensor is on a front surface side or a back surface side of a label, so that a user can easily recognize to which portion of a label an adhesive layer is formed, and user convenience is provided.

Description

Technical Field

[0001] This invention relates to a label for identifying defective parts of electrodes for secondary batteries that can be identified from both sides and a method for manufacturing the same. Specifically, the label can be used with sensors on both the front and back sides, and even if sensors are installed at different locations on each production line, defective parts of the electrodes for secondary batteries can be easily identified. Background Technology

[0002] Generally, electrodes for secondary batteries are manufactured by applying active materials, conductive materials, and binders to a thin, plate-shaped current collector and then drying it. During the manufacturing of these thin-plate electrodes, the application of active materials to the current collector surface can lead to the introduction of external impurities, causing defects, or uneven coating of the active materials, resulting in inherent defects. Therefore, after manufacturing the electrodes, they are always first wound onto a winding roller and then unwound. The entire surface is then inspected for defects and marked. The electrodes are then rewound onto another winding roller for packaging or transferred to a cutting process to remove the marked defective portions, using only the normal electrode parts.

[0003] In addition, with the increasing demand for electrodes for secondary batteries, automated production processes have been introduced. In order to easily mark the defective parts generated on the surface of the electrodes for secondary batteries in the automated production process, and at the same time prevent new defects caused by adhesives, the applicant's prior patent 1 has disclosed a label for identifying defective parts of electrodes for secondary batteries. The amount of adhesive and the position of the adhesive layer are adjusted to the optimal level, so as to minimize the possibility of secondary damage or defects on the surface and back of the thin plate-shaped electrodes for secondary batteries.

[0004] However, a new problem with prior patent 1 is that, only when sensors are provided on the sides of the label where the thermosetting silicone resin layer is formed can defects in the electrodes for secondary batteries be identified. When facing the back of the adhesive layer where the color layer is not visible, the location where the label is pasted cannot be accurately identified. In particular, with the diversification of manufacturing processes recently, the placement of sensors in different manufacturing processes has become more frequent. The label disclosed in prior patent 1 has the limitation that the sensors can only identify the surface side of the label, thus reducing its applicability.

[0005] Therefore, the applicant recognizes the need to develop a new label for identifying defective parts of electrodes for secondary batteries that can retain and further improve upon the advantages of the label in the applicant's prior patent 1, and can easily and accurately identify defective parts of electrodes for secondary batteries with the label affixed, regardless of where the sensor is placed in the manufacturing process of the electrodes for secondary batteries.

[0006] Prior patent documents

[0007] Patent documents

[0008] Prior Patent 1: Korean Patent No. 10-1330880 (granted on November 12, 2013) Summary of the Invention

[0009] Technical problems to be solved

[0010] This invention was proposed to overcome the limitations of conventional technology. The purpose of this invention is to provide a label for identifying defective parts of electrodes for secondary batteries that can be identified from both sides. Even when the components of the production line for producing electrodes for secondary batteries are not fixed and are different from each other, the defective parts can be easily identified regardless of whether the sensor is located on the front or back side of the label.

[0011] Furthermore, another objective of the present invention is to provide a label for identifying defective parts of electrodes for secondary batteries that can be identified from both sides, forming an adhesive layer marking portion so that users can easily identify which part of the label the adhesive layer is formed on, providing convenience to users, and enabling the label to be pasted evenly, thus more accurately identifying defective parts of electrodes for secondary batteries.

[0012] Technical solutions to the problem

[0013] The defect identification label for electrodes in a rechargeable battery that can be identified from both sides is characterized by comprising: a release paper, one side of which is coated with silicone resin to form an integral silicone resin layer; an adhesive layer, on the side above the silicone resin layer coated on the release paper, having an acrylic removable adhesive coated only on a portion corresponding to 25-50% of the total area of ​​the silicone resin layer, with a thickness of 5-30 μm; and a base film, covering the adhesive layer and corresponding to the total area of ​​the release paper, formed of a transparent synthetic resin, wherein on the side facing the adhesive layer, a first colored layer coated with a certain color that can be identified using a certain sensor is sequentially formed, a white layer covering the first colored layer and coated onto the surface, and a second colored layer covering the white layer and coated onto the surface, also coated with a certain color that can be identified using a certain sensor.

[0014] The acrylic removable adhesive is an adhesive formed by the polymerization reaction of acrylic monomers, and is an adhesive mainly composed of acrylic polymers. Preferably, acrylates or methacrylates are used. Acrylic removable resins are used to achieve high adhesion to large surfaces and to prevent electrode defects from recurring due to adhesive leakage during adhesion. Regarding the adhesive adhesion value required by this invention, preferably, it is 100–800 gr / 25 mm when the measuring mechanism removes the product at a 90-degree angle, and 100–1400 gr / 25 mm when removing the product at a 180-degree angle. Furthermore, preferably, the thickness of the adhesive layer is 5–30 μm. Forming an adhesive layer within this range prevents adhesive leakage due to applied pressure during the winding step after inspecting defective portions of the secondary battery electrode.

[0015] Preferably, the base film is made of any one of polyethylene terephthalate (PET), polypropylene (PP), oriented polypropylene (OPP), and polyimide (PI). Because when a transparent synthetic resin is used, the first and second color layers can be easily identified on both the front and back sides of the label. The hardness and stiffness vary depending on the type of base film, and therefore the thickness can be adjusted within the specified range. Therefore, when using a harder material like PET or PP, the thickness is preferably no more than 38 μm; when using a softer material like OPP or PI, a film thickness of 40 μm or more can be used. Therefore, preferably, the thickness of the base film constituting the label of the present invention is 16–50 μm, but its thickness varies depending on the material of the base film. When wrapping and pasting the label onto a thin sheet made of electrodes for secondary batteries, the thickness of the base film is adjusted to avoid leaving adhesive marks on the label. Another feature of the present invention is that, when polyethylene terephthalate is used as the base film material, the other side of the base film also includes a silicone-cured resin layer formed by coating with silicone resin and then curing it under ultraviolet light. Preferably, the thickness of the silicone-cured resin layer is 2 to 5 μm. The function of the silicone-cured resin layer is to minimize secondary contamination or impact on the electrode plates of the secondary battery that come into contact with it when the defective parts are inspected in the state of being labeled. However, when the base film material is polypropylene or oriented polypropylene, the formation of the silicone-cured resin layer would reduce the color recognition rate of the infrared sensor for the defective parts, potentially leading to errors. Therefore, a separate silicone-cured resin layer is not formed.

[0016] In this invention, the sensor used to identify defective portions of the secondary battery electrode can be either a color sensor or an infrared sensor. When using a sensor that identifies the color itself, the first and second color layers can use multiple colors. If an infrared sensor is used, preferably, both the first and second color layers use red, which is easily identifiable by an infrared sensor. Therefore, regardless of where the sensor is placed in the automated manufacturing process of the secondary battery electrode, for the portion where the label of this invention is affixed, in addition to the sensor positioned on the surface side of the label (i.e., from top to bottom), a sensor positioned on the back side (i.e., from bottom to top) can also easily identify defective portions of the secondary battery electrode. Furthermore, besides a color sensor that distinguishes the identification color based on the colors of the first and second color layers, an infrared sensor that only identifies red can also be selectively used.

[0017] Furthermore, in the components of the present invention, preferably, the thicknesses of the first colored layer, the white layer, and the second colored layer included in the base film are 2 to 5 μm, respectively. When identifying colors using a color sensor or an infrared sensor, a white layer is formed between the first colored layer and the second colored layer to ensure accurate color identification on both the surface and back sides and to prevent the penetration or mixing of different colors.

[0018] Furthermore, the present invention is characterized by including, as an additional component, an adhesive layer marking portion, which is formed in the form of a groove at any one of the intersections of the boundary of the portion forming the adhesive layer and the upper and lower ends of the label. This adhesive layer marking portion allows the user to easily peel the label off the release paper and makes the adhesion of uneven labels more uniform. Additionally, when adhering to defective portions of electrodes for secondary batteries, it is easy to determine where the adhesive begins to form, providing convenience to the user.

[0019] Using the adhesive layer as a boundary, a groove of a specific shape is formed at the intersection of the upper and lower ends of the label by stamping, thereby forming the adhesive layer marking part. The groove can be semi-circular, semi-octagonal, semi-quadrilateral, or other semi-circular or semi-polygonal shapes.

[0020] According to another aspect of the present invention, a method for manufacturing a label for identifying defective portions of electrodes for a rechargeable battery that can be identified from both sides includes the following steps: a step of preparing a base film formed of a transparent synthetic resin; a first color layer forming step of applying a first color to the back side of the prepared base film and drying it to form a first color layer; a white layer forming step of applying white to the surface of the first color layer and drying it to form a white layer; a second color layer forming step of applying a second color to the surface of the white layer and drying it to form a second color layer; an adhesive layer forming step of applying an acrylic removable adhesive to the side of the release paper on which the silicone resin layer is formed, covering only 25 to 50% of the total surface area of ​​the release paper to form an adhesive layer; and a release paper bonding step of bonding the surface of the release paper on which the adhesive layer is formed to the second color layer of the base film to each other.

[0021] In addition, another feature of the present invention is that, after the second color layer forming step, it further includes a silicone curing resin layer forming step, wherein after applying silicone resin to the surface of the base film, it is irradiated with ultraviolet light to harden it, thereby forming a silicone curing resin layer.

[0022] In addition, another feature of the present invention is that, in order to enable users to easily identify which part of the label's adhesive layer is formed, after the release paper merging step, an adhesive layer marking part forming step is further included, in which an adhesive layer marking part in the shape of a groove is formed by stamping at any one or more of the intersections between the boundary of the part where the adhesive layer is formed and the upper and lower ends of the label.

[0023] The effects of the invention

[0024] The advantage of this invention is that, even when the components of the production line for producing electrodes for secondary batteries are not fixed and are different from each other, the defective parts of the electrodes for secondary batteries can be easily identified regardless of whether the sensor is located on the surface or the back side of the label.

[0025] Furthermore, another advantage of the present invention is that by adding an adhesive layer marking portion, users can easily identify which part of the label the adhesive layer is formed on, providing convenience to users, and enabling the label to be pasted evenly, thus more accurately identifying defective parts of the electrodes for secondary batteries. Attached Figure Description

[0026] Figure 1 The overall structure of the label of the present invention is shown from the outside.

[0027] Figure 2 A cross-section of the A-A' portion of the label of the present invention is shown.

[0028] Figure 3 The overall manufacturing process of the label of the present invention is shown.

[0029] Explanation of reference numerals in the attached figures

[0030] 100: Release paper; 110: Silicone resin layer

[0031] 200: Adhesion layer

[0032] 300: Base film; 310: First color layer

[0033] 320: White layer; 330: Second color layer

[0034] 400: Silicone-cured resin layer

[0035] 500: Adhesive layer markings

[0036] S100: Base film preparation steps S200: First colored layer formation steps

[0037] S300: White layer formation step; S400: Second color layer formation step

[0038] S500: Silicone Curing Resin Layer Formation Steps

[0039] S600: Adhesion layer formation steps

[0040] S700: Release Paper Assembly Steps

[0041] S800: Adhesive layer marking step. Detailed Implementation

[0042] An embodiment of the present invention will now be described in detail with reference to the accompanying drawings.

[0043] Figure 1 The overall structure of the label of the present invention as viewed from the outside is shown. Figure 2 A cross-section of the A-A' portion of the label of the present invention is shown.

[0044] As one embodiment of the label of the present invention, it includes: a release paper 100, on one side of which a silicone resin layer 110 is integrally formed; an adhesive layer 200, formed by applying an adhesive to only 30% of the total area of ​​one side surface of the silicone resin layer 110; and a base film 300, formed by sequentially applying a first color layer 310, a white layer 320, and a second color layer 330 on top of the adhesive layer 200 and facing the back of the adhesive layer. The thicknesses of the first color layer, the white layer, and the second color layer are 2 to 3 μm, which is sufficient to prevent the colors of the first color layer and the second color layer from penetrating or mixing with each other.

[0045] The base film 300 is made of PET. When the base film is made of PET, the surface of the base film 300 must be coated with a silicone-cured resin layer 400.

[0046] in addition, Figure 1 In order to show that the wires representing the adhesion layer 200 are located below the base film 300, the parts covered by the base film 300 are marked with dashed lines for ease of understanding.

[0047] Furthermore, the adhesive layer 200 forms from one side of the release paper 100, covering 25% to 50% of the total area. This is to allow users to easily peel off the release paper and attach the label, and to easily remove labels that have already been applied to the electrode sheet. However, when the area of ​​the adhesive layer 200 forms from one side of the release paper 100 and reaches less than 25% of the total area of ​​the release paper, the base film may easily detach from the release paper. Therefore, the minimum area of ​​the adhesive layer is limited to 25% of the total area of ​​the release paper. Additionally, if the area of ​​the adhesive layer exceeds 50% of the total area of ​​the release paper, since the label is attached to the surface of the secondary battery electrode in label form, if the adhesive layer also forms on the side that functions as the label, it could damage other, defect-free parts of the electrode. In this embodiment, the area of ​​the adhesive layer is approximately 30% of the total area of ​​the release paper. In this embodiment, to achieve sufficient adhesion while preventing easy separation from the release paper, the thickness of the adhesive layer is 10 to 20 μm, taking into account the area where the adhesive layer is formed.

[0048] Furthermore, to improve user convenience at the work site, adhesive layer marking portions 500 with semi-circular grooves are added to the upper and lower portions where the adhesive layer and the label intersect. The adhesive layer marking portions 500 are formed on one or more sides of the portion where the label's upper or lower end intersects with the boundary of the adhesive layer. In this embodiment, semi-circular groove-shaped adhesive layer marking portions 500 are formed on both the upper and lower portions of the label.

[0049] In addition, compared to performing a separate coating process on the release paper 100 to form the silicone resin layer 110, it is preferable to use an integral product in which the silicone resin layer is integrally formed on the release paper, which can shorten the manufacturing process.

[0050] In addition, the base film used in this embodiment has a thickness of 38 μm. To ensure that no traces are left before and after the winding and unwinding process of the electrode sheet, and to prevent any residual images from being left on the back side of the electrode for the secondary battery, a silicone curing resin layer 400 is formed. The thickness of the silicone curing resin layer 400 is approximately 2 to 3 μm.

[0051] Figure 3 The overall manufacturing process of the label of the present invention is shown.

[0052] The base film preparation step (S100) is the step of preparing the base film formed from a transparent synthetic resin to be used in this invention. In this embodiment, a film of PET material with a thickness of 38 μm is used.

[0053] The first color layer forming step (S200) is a step in which a first color is applied to the back side of the prepared base film, i.e., the side that is joined with the release paper, and then dried to form the first color layer. After the first color layer forming step (S200), after the pigment applied to the first color layer has completely dried, the base film with the first color layer applied is then rolled up.

[0054] The white layer formation step (S300) involves unwinding the base film coated with the first color layer, applying white pigment to the surface of the first color layer, and drying it to form a white layer. The base film with the white layer formed is then wound up again to prepare for the next step, the second color layer formation step.

[0055] The second color layer forming step (S400) is to unwrap the base film that has been sequentially coated with the first color layer and the white layer, apply a pigment of the second color to the surface of the white layer and dry it to form the second color layer.

[0056] The thickness of the first colored layer, the white layer, and the second colored layer are all controlled by the amount of pigment used and the number of coats applied in each step.

[0057] The silicone-curable resin layer formation step (S500) involves coating the surface of the base film with silicone resin and then irradiating it with ultraviolet light to cure it, thereby forming a silicone-curable resin layer. When PET is used as the base film material, a silicone-curable resin layer must be formed on its surface to avoid damaging the electrodes for the secondary battery and to ensure that the label of the present invention is not affected even if it is sandwiched in the middle during the winding of the electrodes for the secondary battery in a thin film state.

[0058] The adhesive layer forming step (S600) involves applying an acrylic removable adhesive to only 25-50% of the total surface area of ​​the release paper on the side where the silicone resin layer is formed, thereby forming an adhesive layer. As mentioned above, although there are cases where a silicone resin layer is applied separately to the release paper and it is used, it is preferable to use release paper that has already been pretreated to form a silicone resin layer.

[0059] After the adhesive layer forming step (S600), a release paper bonding step (S700) can be performed to bond the surface of the release paper forming the adhesive layer with the second color layer of the base film to each other in order to manufacture the label of the present invention.

[0060] In addition, preferably, in order to provide user convenience and enable them to easily identify which part of the label's adhesive layer is formed, after the release paper merging step (S700), an adhesive layer marking part forming step (S800) is further included, in which an adhesive layer marking part in the shape of a groove is formed by stamping at any one or more of the intersections between the boundary of the part where the adhesive layer is formed and the upper and lower ends of the label.

Claims

1. A label for identifying a defective portion of an electrode for a secondary battery which can be identified on both sides, characterized by include: Release paper, one side of which is coated with silicone resin to form a silicone resin layer integrally; An adhesive layer, on the side above the silicone resin layer applied to the release paper, is coated with an acrylic removable adhesive only on a portion corresponding to 25-50% of the total area of ​​the silicone resin layer, with a thickness of 5-30 μm. and A base film, covering the adhesive layer and corresponding to the overall area of ​​the release paper, is formed of a transparent synthetic resin. On one side facing the adhesive layer, a first colored layer coated with a certain color that can be identified by a certain sensor is sequentially formed, followed by a white layer covering the first colored layer and coated onto the surface, and a second colored layer covering the white layer and coated onto the surface, also coated with a certain color that can be identified by a certain sensor. The thicknesses of the first color layer, the white layer, and the second color layer are 2~5μm, respectively.

2. The label for identifying defective portions of electrodes for rechargeable batteries that can be identified from both sides according to claim 1, characterized in that, The base film is made of any one of polyethylene terephthalate, polypropylene, oriented polypropylene, or polyimide.

3. The label for identifying defective portions of electrodes for secondary batteries that can be identified from both sides according to claim 2, characterized in that, When the base film is made of polyethylene terephthalate, The other side of the base film also includes a silicone-cured resin layer formed by applying silicone resin and then curing it with ultraviolet light.

4. The label for identifying defective portions of electrodes for rechargeable batteries that can be identified from both sides according to claim 3, characterized in that, The thickness of the silicone-cured resin layer is 2~5μm.

5. The label for identifying defective portions of electrodes for secondary batteries that can be identified from both sides according to claim 1, characterized in that, The thickness of the base film is 16~50μm.

6. The label for identifying defective portions of electrodes for rechargeable batteries that can be identified from both sides according to claim 1, characterized in that, The sensor is either a color sensor or an infrared sensor.

7. The double-faced recognizable defective portion-recognizable label for an electrode of a secondary battery according to any one of claims 1 to 6, characterized by Also includes: An adhesive layer marking portion is formed in the form of a groove at any one of the intersections of the boundary of the portion forming the adhesive layer and the upper and lower ends of the label.

8. A method for manufacturing a label for identifying defective portions of electrodes in a rechargeable battery that can be identified from both sides, characterized in that, Includes the following steps: The steps for preparing a base film made of transparent synthetic resin; The first color layer forming step involves applying a first color to the back of the prepared base film and drying it to form the first color layer. The white layer formation step involves applying white paint to the surface of the first colored layer and drying it to form a white layer. The second color layer forming step involves applying a second color to the surface of the white layer and drying it to form the second color layer. In the adhesive layer formation step, an acrylic adhesive that can be removed is applied to only 25-50% of the total surface area of ​​the release paper on one side of the release paper where the silicone resin layer is formed, thereby forming an adhesive layer. and The release paper bonding step causes the surface of the release paper forming the adhesive layer to adhere and bond with the second colored layer of the base film. The thicknesses of the first color layer, the white layer, and the second color layer are 2~5μm, respectively.

9. The method for manufacturing a label for identifying defective portions of electrodes for double-sided rechargeable batteries according to claim 8, characterized in that, After the second color layer formation step, the method further includes a silicone curing resin layer formation step, in which silicone resin is coated on the surface of the base film and then cured by irradiation with ultraviolet light to form a silicone curing resin layer.

10. The method for manufacturing a label for identifying defective portions of electrodes for double-sided rechargeable batteries according to claim 8 or 9, characterized in that, After the release paper merging step, the method further includes an adhesive layer marking part forming step, in which an adhesive layer marking part in the shape of a groove is formed by stamping at any one or more of the intersections between the boundary of the portion forming the adhesive layer and the upper and lower ends of the label.

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