Current collector for electrodes with a fuse-integrated blank section and secondary battery including the same

Abstract

An electrode current collector having a fuse-integrated blank portion according to one embodiment of the present invention includes an electrode plate made of a metal material to which an electrode active material is applied or coated; and a blank portion formed at one end of the electrode plate where the electrode active material is absent; wherein the blank portion includes a current path portion formed such that its length in the width direction is narrower or shorter than that of other portions, and a cut portion formed on one side of the current path portion such that the blank portion is absent; and a reinforcing portion may be attached to at least one of the two surfaces of the blank portion, provided to cover at least one of the current path portion or the cut portion, or provided not to cover all or part of the current path portion.

Description

Technical Field

[0001] The present invention relates to a current collector for an electrode having an integrated fuse-free portion and a secondary battery including the same. More specifically, the present invention relates to a current collector for an electrode having an integrated fuse-free portion that can cut off a short-circuit current in the fuse-free portion when a short circuit occurs by removing a part of the fuse-free portion where no electrode active material exists, and a secondary battery including the same.

Background Art

[0002] Secondary batteries that can be charged and discharged are proposed as a solution to solve air pollution and the like of conventional gasoline vehicles and diesel vehicles that use fossil fuels, such as electric vehicles (EVs), hybrid electric vehicles (HEVs), and plug-in hybrid electric vehicles (Plug-In HEVs). They are attracting attention as a power source for devices that require high output and large capacity.

[0003] For such devices, in order to provide high output and large capacity, a medium to large-sized battery module in which a large number of battery cells are electrically connected is used.

[0004] Since it is desirable that the medium to large-sized battery module be manufactured as small and light as possible, prismatic batteries, pouch-type batteries, etc. that can be stacked with a high degree of integration and have a small weight relative to the capacity are mainly used as the battery cells (unit cells) of the medium to large-sized battery module.

[0005] In particular, a pouch-type battery having a structure in which a stacked or stacked / folding-type electrode assembly is incorporated in a pouch-type battery case made of an aluminum laminate sheet has attracted a lot of attention due to reasons such as low manufacturing cost, light weight, and easy form deformation, and its usage amount is gradually increasing. On the other hand, lithium-ion batteries contain various flammable materials and pose a significant safety risk due to overheating, overcurrent, and other physical external shocks. Therefore, lithium-ion batteries are equipped with safety elements such as PTC (Positive Temperature Coefficient) elements and Protection Circuit Modules (PCMs) connected to the battery cells, which can effectively control abnormal conditions such as overcharging and overcurrent. However, while safety can be ensured when using such safety elements, it comes with disadvantages such as increased component costs, increased complexity of the manufacturing process, and a decrease in battery capacity per unit volume. Therefore, in this industry, attempts have been made to invent ways to ensure safety in the event of overcurrent without using safety elements such as PTC elements and protection circuit modules. In this process, there have been attempts to attach fuses to the electrode leads, but it is difficult to guarantee that the fuse will cut off in the event of an overcurrent, making it difficult to expect a rapid cutoff. Furthermore, the low strength of the fuse mounting area results in poor durability. Therefore, there is a strong need to develop electrode current collectors and secondary batteries that can guarantee the fuse will shut off when short-circuit currents or overcurrents are present, enable rapid power cutoff, and ensure the strength of the fuse-forming area. The applicant has proposed the present invention in order to solve the above-mentioned problems. Related prior art includes Korean Patent Publication No. 10-1302430 (Title of Invention: Secondary Battery Equipped with Fuse-Integrated Electrode Leads, Registration Date: 2013.08.20). [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Korean Registered Patent Publication No. 10-1302430 [Overview of the Initiative] [Problems that the invention aims to solve]

[0007] This invention was proposed to solve the above-mentioned problems and provides an electrode current collector having a fuse-integrated blank section in which the blank section can function as a fuse, and a secondary battery including the same.

[0008] The present invention provides an electrode current collector having a fuse-integrated blank portion that can prevent a decrease in rigidity of the blank portion on which the fuse is formed, and a secondary battery including the same.

[0009] The present invention provides an electrode current collector having a fuse-integrated blank section that allows for easy processing of a cut section capable of performing a fuse function, and a secondary battery including the same.

[0010] The problems that this invention aims to solve are not limited to the problems described above, and other problems not mentioned will be clearly understood by those skilled in the art from the following description. [Means for solving the problem]

[0011] To achieve the above-mentioned problems, an electrode current collector having a fuse-integrated blank portion according to one embodiment of the present invention includes: an electrode plate made of a metal material to which an electrode active material is applied or coated; and a blank portion formed at one end of the electrode plate where the electrode active material is absent; wherein the blank portion includes a current path portion formed such that the widthwise length of the blank portion is narrower or shorter than other portions, and a cut portion formed on one side of the current path portion such that the blank portion is absent; and a reinforcing portion can be attached to at least one of the two surfaces of the blank portion, provided to cover at least one of the current path portion or the cut portion, or provided not to cover all or part of the current path portion.

[0012] At least one of the aforementioned incisions or current path portions can be formed along the width direction of the plain portion.

[0013] The length of the current path portion in the width direction of the non-patterned portion can be formed shorter than the width or length of the cut portion.

[0014] The current path portion may be formed so as to be connected to either one of both ends in the width direction of the non-patterned portion, or may be formed in the central portion so as not to be connected to either one of both ends in the width direction of the non-patterned portion.

[0015] The cut portion may be formed on at least one side of both sides of the current path portion along the width direction of the non-patterned portion, or may be formed in a hole shape between the current path portions.

[0016] The cut portion or the current path portion may be formed near the edge of the electrode plate.

[0017] The cut portion may be formed in a state where the reinforcing portion is provided or attached to at least one of both surfaces of the non-patterned portion.

[0018] The cut portion may be formed by removing the non-patterned portion using a laser in a state where the reinforcing portion is provided or attached to at least one of both surfaces of the non-patterned portion.

[0019] The reinforcing portion can be provided with a transparent tape through which light or laser passes.

[0020] The reinforcing portion may be provided so as to cover the current path portion and not cover the cut portion, or may be provided with a length corresponding to the length in the width direction of the non-patterned portion so as to integrally cover the current path portion and the cut portion.

[0021] The reinforcing portion can be provided with a heat-resistant tape.

[0022] In addition, the present invention can provide a secondary battery including the above-described current collector for an electrode.

[0023] Specific details of other embodiments are included in the detailed description and the accompanying drawings.

Advantages of the Invention

[0024] The current collector for an electrode having a fuse-integrated non-patterned portion according to the present invention and the secondary battery including the same do not need to include a separate fuse because the non-patterned portion can exhibit a fuse function.

[0025] The current collector for an electrode having a fuse-integrated non-patterned portion according to the present invention and the secondary battery including the same include a slit formed in the non-patterned portion, and are provided with a tape-shaped reinforcing portion attached to at least one of both surfaces of the non-patterned portion or covering at least one of both surfaces, thereby preventing the rigidity or strength of the non-patterned portion from being reduced by the slit. When the current path portion is bent, the reinforcing portion can prevent the current path portion from being immediately cut or damaged.

[0026] The current collector for an electrode having a fuse-integrated non-patterned portion according to the present invention and the secondary battery including the same can easily form a slit by removing the non-patterned portion using a laser while a transparent or light-transmissive tape-shaped reinforcing portion is attached to at least one of both surfaces of the non-patterned portion, and can form slits in various forms.

[0027] In the current collector for an electrode having a fuse-integrated non-patterned portion according to the present invention and the secondary battery including the same, since the reinforcing portion provided on at least one of both surfaces of the non-patterned portion is transparent, the slit can be accurately processed while confirming the position of the tip of the laser.

[0028] The current collector for an electrode having a fuse-integrated non-patterned portion according to the present invention and the secondary battery including the same are attached to at least one of the current path portion or the slit using a reinforcing portion provided with a heat-resistant tape such as polyimide instead of an OPP tape, so that even when the temperature of the secondary battery rises during a short circuit, the reinforcing portion does not catch fire, and the generation of sparks or smoke can be prevented or delayed.

Brief Description of the Drawings

[0029] [Figure 1] This is a perspective view showing a secondary battery including an electrode current collector having a fuse-integrated blank section according to one embodiment of the present invention. [Figure 2] Figure 1 is a perspective view showing the inside of a secondary battery. [Figure 3] Figure 1 is a plan view showing the inside of a secondary battery. [Figure 4] This is a plan view showing an electrode current collector having a fuse-integrated blank section according to one embodiment of the present invention. [Figure 5] This is a plan view showing an electrode current collector having a fuse-integrated blank section according to one embodiment of the present invention. [Figure 6] This figure shows a blank section with an integrated fuse according to one embodiment of the present invention. [Figure 7] This figure shows a blank section with an integrated fuse according to one embodiment of the present invention. [Figure 8] This figure shows a blank section with an integrated fuse according to one embodiment of the present invention. [Figure 9] This figure shows a blank section with an integrated fuse according to one embodiment of the present invention. [Figure 10] This figure shows a blank section with an integrated fuse according to one embodiment of the present invention. [Figure 11] This figure shows a fuse-integrated blank section according to yet another embodiment of the present invention. [Figure 12] This figure shows a fuse-integrated blank section according to yet another embodiment of the present invention. [Figure 13] This figure shows a fuse-integrated blank section according to yet another embodiment of the present invention. [Figure 14] This figure shows a fuse-integrated blank section according to yet another embodiment of the present invention. [Figure 15] This figure shows a fuse-integrated blank section according to yet another embodiment of the present invention. [Figure 16] This figure shows a fuse-integrated blank section according to yet another embodiment of the present invention. [Figure 17]This figure shows a fuse-integrated blank section according to yet another embodiment of the present invention. [Figure 18] This graph shows the results of a short-circuit current experiment on the blank positive electrode portion of a fuse-integrated fuse according to one embodiment of the present invention. [Figure 19] This graph shows the results of a short-circuit current experiment on the blank positive electrode portion of a fuse-integrated fuse according to one embodiment of the present invention. [Modes for carrying out the invention]

[0030] The embodiments disclosed herein will be described in detail below with reference to the attached drawings, but identical or similar components will be denoted by the same or similar reference numerals, and redundant descriptions will be omitted. The suffix "part" used for components in the following description is for the convenience of drafting the specification, and is added or mixed in sole consideration, and does not have any meaning or role that distinguishes them from each other in itself. Furthermore, in describing the embodiments disclosed herein, if it is determined that a specific description of related known technology would unnecessarily obscure the gist of the embodiments disclosed herein, such detailed description will be omitted. In addition, the attached drawings are merely for the purpose of facilitating the understanding of the embodiments disclosed herein, and the attached drawings are not intended to limit the technical ideas disclosed herein, and should be understood to include any modifications, equivalents or substitutes that fall within the concept and technical scope of the present invention.

[0031] Terms including ordinal numbers, such as "first," "second," etc., may be used to describe a variety of components, but the components are not limited to those defined by these terms. These terms are used solely for the purpose of distinguishing one component from another.

[0032] When it is stated that one component is "connected" to another, it is important to understand that while it may be directly connected to the other component, there may also be other components in between.

[0033] Unless the context clearly indicates a different meaning, singular expressions shall be considered to include plural expressions.

[0034] In this application, terms such as “includes” or “having” should be understood to mean the presence of features, figures, stages, operations, components, parts, or combinations thereof described in the specification, and not to preemptively exclude the possibility of the presence or addition of one or more other features, figures, stages, operations, components, parts, or combinations thereof.

[0035] It should be noted in advance that the drawings are schematic and not drawn to scale. The relative dimensions and proportions of each part in the drawings are exaggerated or reduced in size for clarity and convenience in the drawings, and any dimensions are illustrative and not limiting. Furthermore, the same reference numerals are used to indicate similar features for the same structure, element, or part shown in two or more drawings.

[0036] The embodiments of the present invention specifically illustrate ideal embodiments of the present invention. As a result, various modifications of the drawings are expected. Therefore, the embodiments are not limited to specific forms of the shown regions, and include, for example, modifications of form due to manufacturing.

[0037] Hereinafter, embodiments of the present invention will be described in detail with reference to the attached drawings.

[0038] Figure 1 is a perspective view showing a secondary battery including an electrode current collector with a fuse-integrated blank section according to one embodiment of the present invention; Figure 2 is a perspective view showing the interior of the secondary battery according to Figure 1; Figure 3 is a plan view showing the interior of the secondary battery according to Figure 1; Figures 4 and 5 are plan views showing an electrode current collector with a fuse-integrated blank section according to one embodiment of the present invention; Figures 6 to 10 show a fuse-integrated blank section according to one embodiment of the present invention; Figures 11 to 13 show a fuse-integrated blank section according to another embodiment of the present invention; Figures 14 to 17 show a fuse-integrated blank section according to yet another embodiment of the present invention; and Figures 18 and 19 are graphs showing the results of a short-circuit current experiment on a fuse-integrated positive electrode blank section according to one embodiment of the present invention.

[0039] Referring to Figures 1 and 2, a secondary battery 1 according to one embodiment of the present invention may include an electrode assembly 10 and an outer casing 11. The outer casing 11 can also be referred to as a pouch.

[0040] The electrode assembly 10 has a configuration in which positive electrode plates 101, a separator membrane (not shown), and negative electrode plates 201 are alternately stacked. That is, the electrode assembly 10 is obtained by alternately stacking (stacking) positive electrode plates 101, a separator membrane (not shown), and negative electrode plates 201 such that the separator membrane is positioned between the positive electrode plate 101 and the negative electrode plate 201.

[0041] In the following, "electrode" (101, 201) refers to a positive electrode or cathode (101) and a negative electrode or anode (201).

[0042] The positive electrode plate 101 may be made of aluminum metal foil, and at least one surface may be coated or applied with a positive electrode active material (not shown). The positive electrode active material can be formed from layered compounds such as lithium cobalt oxide (LiCoO2) or lithium nickel oxide (LiNiO2), or compounds substituted with one or more transition metals.

[0043] While the positive electrode plate 101 located in the central part of the electrode assembly 10 has positive electrode active material formed on both sides, the positive electrode plate 101 located at the bottom or top of the electrode assembly 10 can have positive electrode active material formed on only one side, that is, the side facing the outer casing material 11.

[0044] The negative electrode plate 201 may be made of copper metal foil, and at least one surface may be coated with a negative electrode active material (not shown). The negative electrode active material may be made of carbon, for example, poorly graphitized carbon, graphite-based carbon, etc.

[0045] While the negative electrode plate 201 located in the central part of the electrode assembly 10 has negative electrode active material formed on both sides, the negative electrode plate 201 located at the bottom or top of the electrode assembly 10 can have negative electrode active material formed on only one side, that is, the side facing the outer casing material 11.

[0046] The separation membrane (separator) may be a thin, insulating film having high ion permeability and mechanical strength. The separation membrane can be formed from an olefin polymer, such as chemically resistant and hydrophobic polypropylene or polyethylene.

[0047] The outer material 11 that houses the electrode assembly 10 may include a lower part 13 and an upper part 12. The lower part 13 of the outer material 11 may include a housing portion 14 and a lower sealing portion 13a formed on the edge of the housing portion 14.

[0048] The housing section 14 can be formed by press-forming the lower part 13 of the exterior material 11 and can accommodate the electrode assembly 10. The lower sealing section 13a can be formed by bending and extending outward from the upper edge of the housing section 14.

[0049] The upper part 12 of the exterior material 11 may include an upper sealing part 12a that corresponds to the lower sealing part 13a. The upper sealing part 12a is bonded to the lower sealing part 13a by heating and pressurizing, thereby maintaining airtightness inside the exterior material 11.

[0050] Furthermore, a long, protruding positive electrode blank portion 120 can be formed on one side of the edge of the positive electrode plate 101. The positive electrode blank portion 120 does not contain positive electrode active material. Similarly, a long, protruding negative electrode blank portion 220 can be formed on one side of the edge of the negative electrode plate 201. The negative electrode blank portion 220 does not contain negative electrode active material.

[0051] When stacking the positive electrode plate 101 and the negative electrode plate 201 alternately to form the electrode assembly 10, the blank positive electrode portions 120 and the blank negative electrode portions 220 are brought together, as shown in Figures 1 to 3. At this time, it is necessary to keep the blank positive electrode portions 120 and the blank negative electrode portions 220 separate so that they do not come into contact with each other.

[0052] A positive lead tab 111 and a negative lead tab 211 can be connected to the combined positive electrode blank section 120 and negative electrode blank section 220, respectively. An insulating tape 112 can be provided at the point where the positive electrode blank section 120 and the positive electrode lead tab 111 are connected. Similarly, an insulating tape 212 can be provided at the point where the negative electrode blank section 220 and the negative electrode lead tab 211 are connected.

[0053] As shown in Figure 3, when the upper sealing portion 12a and the lower sealing portion 13a of the exterior material 11 are bonded together, the insulating tapes 112 and 212 are positioned between the upper sealing portion 12a and the lower sealing portion 13a.

[0054] In the following, with reference to Figures 4 to 10, an electrode current collector 100, 200 having a fuse-integrated blank section according to one embodiment of the present invention will be described. The electrode current collector (100, 200) is a metal current collector formed from a metal such as aluminum or copper.

[0055] As shown in Figure 4, a current collector 100, 200 for a metal electrode, comprising a fuse-integrated blank portion 120, 220 according to one embodiment of the present invention, may include a metal electrode plate 101, 201 on which an electrode active material is applied or coated; and a blank portion 120, 220 formed at one end of the electrode plate 101, 201 where no electrode active material is present. Here, the blank portion 120, 220 can be formed as an extension from one end of the metal electrode plate 101, 201.

[0056] Figure 4 shows a state in which the positive electrode plate 101 and the negative electrode plate 201 are stacked. In Figure 4, the negative electrode plate 201 is located on top, and the positive electrode plate 101 is located below the negative electrode plate 201. Since the positive electrode plate 101 is smaller than the negative electrode plate 201, the positive electrode plate 101 and the negative electrode plate 201 are stacked alternately so that the positive electrode plate 101 is located inside the edge of the negative electrode plate 201.

[0057] The blank positive electrode portion 120 may include a lead tab connecting portion 121, a current path portion 123, and a cut portion 125. Similarly, the blank negative electrode portion 220 may include a lead tab connecting portion 221, a current path portion 223, and a cut portion 225.

[0058] An electrode current collector 100, 200 according to one embodiment of the present invention may include a current collector for a positive electrode or cathode (100) and a current collector for a negative electrode or anode (200). Since the form or structure of the current collector for a positive electrode 100, which includes a positive electrode plate 101 and a blank positive electrode portion 120, is the same as the form or structure of the current collector for a negative electrode 200, which includes a negative electrode plate 201 and a blank negative electrode portion 220, the current collector for a positive electrode 100 will be described below.

[0059] Referring to Figures 5 to 10, the blank positive electrode portion 120 may have a cut portion 225 formed therein that is narrower or shorter than the other portion, namely the lead tab connecting portion 121. In other words, the blank positive electrode portion 120 may not have a uniform width along its longitudinal direction (vertical direction), but may include a cut portion 125 that is relatively narrower or shorter.

[0060] In short, the positive electrode blank portion 120 may include a current path portion 123 formed such that the length of the positive electrode blank portion 120 in the width direction (left-right direction) is narrower or shorter than that of other portions, and a cut portion 125 formed on one side of the current path portion 123 so that the positive electrode blank portion 120 is absent.

[0061] As shown in Figures 6 to 15, in a positive electrode current collector 100 equipped with a fuse-integrated blank portion 120 according to one embodiment of the present invention, at least one or more cut portions 125 can be formed along the width direction of the positive electrode blank portion 120.

[0062] Referring to Figures 6 to 8, two incisions 125 may be formed along the width direction (i.e., left-right direction) of the plain positive pole portion 120 (see Figure 7), or three may be formed (see Figure 8).

[0063] Thus, when at least one or more incisions 125 are formed along the width direction of the blank positive electrode portion 120, current path portions 123 can be formed between the incisions 125. The incisions 125 are portions where the blank positive electrode portion 120 or the positive electrode plate 101 is absent, and the current path portions 123 are portions where the blank positive electrode portion 120 or the positive electrode plate 101 is present. Therefore, the current flowing from the positive electrode plate 101 can flow to the positive electrode lead tab 111 via the current path portions 123.

[0064] As shown in Figures 6 to 8, the current path section 123 can be formed to be shorter than the width or length of the incision section 125. Furthermore, the current path section 123 can be formed to have a length shorter than the width of the lead tab connecting section 121. For example, the lead tab connecting section 121 may have the longest width, followed by the incision section 125, and then the current path section 123. Here, the width direction refers to the left-right direction.

[0065] As shown in Figures 6 to 8, when two or more incisions 125 are formed along the width direction of the positive electrode blank portion 120, the number of current path portions 123 can also be formed to be fewer than the number of incisions 125. In Figure 7, there are two incisions 125, but only one current path portion 123. In Figure 8, there are three incisions 125, but only two current path portions 123.

[0066] Since the current path portion 123 is located between the incisions 125 along the width direction of the positive electrode blank portion 120, the number of current path portions 123 can be formed to be one less than the number of incisions 125.

[0067] As shown in Figure 7, the incision portion 125 can be formed on one side of the current path portion 123, and as shown in Figure 8, the incision portion 126 can be formed between the current path portions 123.

[0068] As shown in Figures 7 and 8, the incision 125 formed on one side of the current path portion 123 can be formed to connect with the widthwise edge of the positive electrode blank portion 120 or the lead tab connecting portion 121. That is, the incision 125 formed on one side of the current path portion 123 can be provided in a form in which one side is open.

[0069] On the other hand, as shown in Figure 8, the incision 126 formed between the current path sections 123 can have a form in which the entire circumference is surrounded by the positive electrode plain section 120 and the current path sections 123 without any open portion. In other words, the incision 126 formed between the current path sections 123 can be provided in the form of a hole.

[0070] As shown in Figures 6 to 8, the incisions 125, 126 and the current path section 123 can be located on the same line along the width direction of the positive terminal blank section 120 or the lead tab connecting section 121, but the incisions 125, 126 and the current path section 123 can also be located on different lines. Furthermore, multiple incisions 125, 126 can be located on different lines, and multiple current path sections 123 can also be located on different lines.

[0071] The incisions 125, 126 or the current path portion 123 can be formed near the edge of the positive electrode plate 101.

[0072] Referring to Figure 6, it is preferable that the incision portion 125 or the current path portion 123 be formed closer to the lower end 121b of the positive electrode blank portion 120 than to the upper end 121a. The lower end 121b of the positive electrode blank portion 120 is connected to the edge of the positive electrode plate 101. Therefore, it is preferable that the incision portions 125, 126 or the current path portion 123 be formed near the edge of the positive electrode plate 101.

[0073] The current generated at the positive electrode plate 101 of the positive electrode current collector 100 flows from the positive electrode plate 101 to the positive electrode blank section 120, and after passing through the positive electrode blank section 120, it is supplied to the external device via the positive electrode lead tab 111. Therefore, the positive electrode blank section 120 acts as a current path.

[0074] However, current cannot flow through the portion of the positive electrode blank portion 120 where the incision portion 125 is formed, and current flows only through the current path portion 123. Because the width of the current path portion 123 is significantly narrower than the width of the other portions, i.e., the portions without the incision portion 125, high resistance may be generated when current passes through the current path portion 125.

[0075] In particular, when a short circuit occurs in the secondary battery 1 including the electrode assembly 10, the short-circuit current flows through the current path section 123. However, this creates high resistance in the current path section 123, causing the temperature of the current path section 123 to rise, and ultimately leading to the current path section 123 being disconnected. In this way, when a short circuit occurs, the current path section 123 is disconnected by the excessive short-circuit current, thereby ensuring the safety of the secondary battery in the event of a short circuit.

[0076] The blank positive electrode portion 120 can function as a fuse due to the cut portion 125 and the current path portion 123 formed in it. Therefore, the blank positive electrode portion 120 becomes a blank portion with an integrated fuse. Similarly, the blank negative electrode portion 220 is also a blank portion with an integrated fuse.

[0077] Furthermore, the formation of the cut portion 125 and the current path portion 123 in the plain positive electrode portion 120 may weaken the strength or rigidity of the plain positive electrode portion 120. Because the width of the current path portion 123 is narrow or short, the current path portion 123 may be cut during the manufacturing process of the electrode assembly 10 or during the transportation of the secondary battery 1. In addition, the current path portion 123 may be cut or damaged if it is folded.

[0078] In one embodiment of the present invention, an electrode current collector 100 equipped with a fuse-integrated blank portion 120 can prevent a decrease in the strength or rigidity of the positive electrode blank portion 120 by attaching a reinforcing portion 130 to at least one of the two surfaces of the positive electrode blank portion 120 along the width direction. This reinforcing portion 130 is provided to cover at least one of the cut portion 125 or the current path portion 123, or is provided not to cover all or part of the current path portion 123. In other words, by providing the reinforcing portion 130, it is possible to prevent a decrease in the strength or rigidity of the positive electrode blank portion 120 or a decrease in its anti-folding stiffness due to the current path portion 123 or the cut portion 125.

[0079] The reinforcing portion 130 can be provided on at least one of the upper or lower surfaces of the positive electrode blank portion 120. The reinforcing portion 130 can be provided only on the upper surface of the positive electrode blank portion 120, only on the lower surface, or on both the upper and lower surfaces.

[0080] The reinforcing portion 130 can be provided to completely cover the cut portions 125, 126 and the current path portion 123, as shown in Figures 6 to 8; it can be provided not to completely cover the current path portion 123 or to only cover a part of it, as shown in Figures 11 to 13; or it can be provided to completely cover only the current path portion 123, as shown in Figures 14 to 17. Although not shown, the reinforcing portion 130 may also be provided or attached to cover other energized parts other than the current path portion 123 in the plain portion 120.

[0081] Thus, the reinforcing portion 130 can be provided to cover only the current path portion 123, not to completely cover the current path portion 123, to cover only a part of the current path portion 123, or to cover both the current path portion 123 and the cut portion 125. Although not shown in the figures, the reinforcing portion 130 may also be attached to other energized portions excluding the current path portion 123.

[0082] The reinforcing portion 130 is provided so as to be attached to at least one of the upper or lower surfaces of the current path portion 123 so as to completely cover the current path portion 123, thereby supplementing the rigidity or strength of the current path portion 123.

[0083] Thus, by providing a reinforcing portion 130 that covers or attaches to at least one of the incision portions 125, 126 or the current path portion 123, the rigidity of the incision portions 125, 126 can be enhanced by the reinforcing portion 130 located in the incision portions 125, 126 that do not have a positive electrode blank portion 120 or a positive electrode plate 101, and the rigidity of the narrow current path portion 123 can also be strengthened by the reinforcing portion 130 attached to at least one surface of the current path portion 123.

[0084] Here, the reinforcing portion 130 can be provided in the form of an OPP (Oriented Polypropylene) tape having an adhesive function or adhesive component. The reinforcing portion 130 provided in the form of an adhesive tape can be provided so as to be attached to at least one of the upper or lower surfaces of the positive electrode plain portion 120. In this case, the reinforcing portion 130 needs to be provided so as to cover or be attached to the cut portions 125, 126 and / or the current path portion 123.

[0085] Furthermore, the reinforcing portion 130 can be provided with a heat-resistant tape such as polyimide instead of OPP tape. By attaching the reinforcing portion 130, provided with a heat-resistant tape such as polyimide, to at least one of the current path portion 123 or the cut portion 125, it is possible to prevent or delay the generation of sparks or smoke in the reinforcing portion 130 even if the temperature of the secondary battery rises due to a short circuit.

[0086] Furthermore, the reinforcing portion 130 not only prevents the strength of the positive electrode plain portion 120 from being reduced by the cut portions 125, 126 or the current path portion 123, but is also necessary for processing and creating the cut portions 125, 126 and the current path portion 123.

[0087] In one embodiment of the present invention, a current collector 100 for a positive electrode, which includes a fuse-integrated blank portion 120, can form cut portions 125, 126, or current path portions 123 after the reinforcing portion 130 has been attached to at least one of the upper and lower surfaces of the positive electrode blank portion 120, with the reinforcing portion 130 attached to or provided on at least one surface of the positive electrode blank portion 120.

[0088] Here, by irradiating the portion of the positive electrode blank portion 120 covered by the reinforcing portion 130 with a laser, the positive electrode blank portion 120 can be removed or the positive electrode plate 101 that forms the positive electrode blank portion 120 can be removed to form the incision portions 125, 126 or the current path portion 123.

[0089] The incisions 125, 126 or the current path 123 may be formed by laser processing or laser cutting, but the reinforcing portion 130 must be made of a transparent material so that the incisions 125, 126 or the current path 123 can be processed using a laser in this manner.

[0090] Since the reinforcing portion 130 is made of a transparent material or transparent tape that allows light or laser to pass through, it is possible to visually confirm whether the laser is irradiating the desired location during laser processing, and whether the incised portions 125, 126 or the current path portion 123 are being processed as designed.

[0091] As shown in Figure 6, a processing line (CL) to create an incision 125 is first marked on the surface of the long, strip-shaped positive electrode blank portion 120. After marking the processing line (CL) on the surface of the positive electrode blank portion 120, the reinforcing portion 130 is attached to at least one of the upper or lower surfaces of the positive electrode blank portion 120 so as to completely cover the processing line (CL).

[0092] At this time, since the reinforcing portion 130 is made of a transparent material or transparent tape that allows light or laser to pass through, the processing line (CL) is visible even when the reinforcing portion 130 is attached to the surface of the positive electrode blank portion 120, and the operator can confirm the processing line (CL) with the naked eye. In this state, the operator can form an incision portion 125 or a current path portion 123 by irradiating a laser along the processing line (CL). That is, by irradiating a laser along the processing line (CL) and removing the portion of the positive electrode blank portion 120 surrounded by the processing line (CL), an incision portion 125 or a current path portion 123 as shown in Figure 7 can be provided.

[0093] Because the reinforcing section 130 is transparent, the operator can perform the processing work while confirming whether the laser is accurately irradiating along the processing line (CL).

[0094] By processing the incision portion 125 using a laser, the current path portion 123 can also be processed as a result. In other words, the incision portion 125 and the current path portion 123 can be created simultaneously by processing the incision portion 125 alone.

[0095] Thus, the incised portions 125 and 126 can be formed such that the reinforcing portion 130 is provided on or attached to at least one of the two surfaces of the positive electrode plain portion 120.

[0096] Furthermore, the incisions 125 and 126 can be formed by removing the plain positive electrode portion 120 using a laser while the reinforcing portion 130 is provided on or attached to at least one of the two surfaces of the plain positive electrode portion 120.

[0097] Figures 9 and 10 show the dimensional relationship of the cut portion 125 or current path portion 123 formed in the blank positive electrode portion 120.

[0098] Figure 9 shows a blank positive electrode section 120 with two incisions 125 and one current path section 123 formed thereon, while Figure 10 shows a blank positive electrode section 120 with three incisions 125, 126 and two current path sections 123 formed thereon.

[0099] First, referring to Figure 9, the width of the cut portion 125 (W2, W3) is smaller than the width of the plain positive electrode portion 120 (W1), and the width of the current path portion 123 (W4) is smaller than the width of the cut portion 125 (W2, W3). The width of the current path portion 123 (W4) can be formed to be about 1 to 5 mm.

[0100] Compared to the length (L1) of the plain positive electrode portion 120, it is preferable that the lengths (L4) of the incision portion 125 and the current path portion 123 be formed to be significantly shorter in relative terms. It is preferable that the lengths (L4) of the incision portion 125 and the current path portion 123 be formed to be about 0.1 to 1 mm.

[0101] Furthermore, it is preferable that the length between the lower ends (L3) of the positive electrode blank portion 120 is longer than the length between the upper ends (L2) of the incision portion 125 or current path portion 123 and the positive electrode blank portion 120. In this way, if the length between the lower ends (L3) of the incision portion 125 or current path portion 123 and the positive electrode blank portion 120 is not shorter than the length between the upper ends (L2) of the positive electrode blank portion 120, the incision portion 125 or current path portion 123 cannot be located close to the positive electrode plate 101.

[0102] Next, referring to Figure 10, the widths of the incised portions 125 and 126 (W2, W3, W5) are smaller than the width (W1) of the plain positive electrode portion 120, and the width of the current path portion 123 (W4, W6) is smaller than the width of the incised portion 125 (W2, W3, W5). It is preferable that the width of the current path portion 123 (W4, W6) be formed to be about 1 to 5 mm.

[0103] Compared to the length (L1) of the plain positive electrode portion 120, it is preferable that the lengths (L4) of the incised portions 125, 126 and the current path portion 123 be formed to be significantly shorter in relative terms. The lengths (L4) of the incised portions 125, 126 and the current path portion 123 can be formed to about 0.1 to 1 mm.

[0104] Furthermore, it is preferable that the length between the lower ends (L3) of the positive electrode blank portion 120 is longer than the length between the upper ends (L2) of the incision portions 125, 126 or the current path portion 123 and the positive electrode blank portion 120. In this way, if the length between the lower ends (L3) of the incision portions 125, 126 or the current path portion 123 and the positive electrode blank portion 120 is not shorter than the length between the upper ends (L2) of the positive electrode blank portion 120, the incision portions 125, 126 or the current path portion 123 cannot be located close to the positive electrode plate 101.

[0105] The above describes the cuts 125, 126, current path portion 123, and reinforcing portion 130 formed on the blank positive electrode portion 120 of the positive electrode current collector 100. However, the cuts 225 and current path portion 223 formed on the blank negative electrode portion 220 of the negative electrode current collector 200 have the same form and function as those formed on the blank positive electrode portion 120, and reinforcing portions (not shown) can also be attached to or provided on the cuts 225 and current path portion 223 of the blank negative electrode portion 220.

[0106] Figures 11 to 13 show a fuse-integrated positive electrode blank portion 120 according to another embodiment of the present invention. Referring to Figures 11 to 13, the reinforcing portion 130 can be provided in a manner that does not completely cover the current path portion 123 or covers only a part of it. In this case, the reinforcing portion 130 can be provided so as not to completely cover the cut portion 125 or not to cover only a part of it.

[0107] As shown in Figure 11, a hole 131 is formed in the reinforcing portion 130, and the current path portion 123 is provided to be exposed through the hole 131, and the cut portion 125 can be provided to be completely covered by the reinforcing portion 130. In this case, the current path portion 123 may be partially covered by the reinforcing portion 130 depending on the size or position of the hole 131.

[0108] As shown in Figures 12 and 13, the reinforcing portion 130 completely covers at least a portion of the incision portion 125, whereas the current path portion 123 may be provided in a form that is divided into multiple parts so as not to completely cover it. If the reinforcing portion 130 does not completely cover the current path portion 123, a portion of the incision portion 125 may also not be covered by the reinforcing portion 130. Although not shown, if the reinforcing portion 130 is provided to completely cover the incision portion 125, it may also be provided to cover a portion of the current path portion 123.

[0109] Figures 14 to 17 show a fuse-integrated positive electrode blank section 120 according to the present invention and another embodiment.

[0110] Referring to Figures 14 and 15, the patterns and positions of the current path section 123 and the incision sections 125 and 126 are the same as those shown in Figures 6 to 8, but the form or position of the reinforcing section 130 differs from those shown in Figures 6 to 8. In Figures 11 to 13, the reinforcing section 130 is provided to completely cover the current path section 123, whereas in Figures 11 to 13, it can be provided in a form that does not completely cover the incision section 125.

[0111] Referring to Figures 6 to 15, the current path portion 123 can be formed to connect to either one end of the plain portion 120 in the width direction, or it can be formed in the central portion so as not to connect to either one end of the plain portion 120 in the width direction. In addition, the incisions 125 and 126 can be formed along the width direction of the plain portion 120 on at least one side of the current path portion 123, or they can be formed in the form of holes 126 between the current path portions 123.

[0112] Referring to Figures 14 and 15, if the reinforcing portion 130 is provided on only one side of the current path portion 123, the same number of reinforcing portions 130 and current path portions 123 can be provided. In the case of Figure 14, there is one current path portion 123 and one reinforcing portion 130, while in the case of Figure 15, there are two current path portions 123 and two reinforcing portions 130.

[0113] Referring to Figures 16 and 17, the patterns and positions of the current path section 123 and the incised sections 125 and 126 also differ from those shown in Figures 6 to 8, and the shape or position of the reinforcing section 130 also differs from those shown in Figures 6 to 8. In Figures 6 to 15, at least one of the incised sections 123 is provided in a form that opens at one end in the width direction of the plain section 120.

[0114] On the other hand, in the cases of Figures 16 and 17, the incision portion 125 is provided at a position separated from one end in the width direction of the plain portion 120, but differs in that it is provided in the form of a hole between the current path portions 123. The reinforcing portion 130 is provided in a form that completely covers the current path portions 123, but the incision portion 125 is provided in the same way as the reinforcing portion 130 in Figures 14 and 15 in that it is not completely covered.

[0115] Thus, as shown in Figures 6 to 8, the reinforcing portion 130 can be provided with a length corresponding to the widthwise length of the plain portion 120 so as to integrally cover the current path portion 123 and the cut portions 125 and 126, or as shown in Figures 11 to 13, it can be provided so as to completely cover the cut portion 125 but not the current path portion 123, or as shown in Figures 14 to 17, it can be provided so as to completely cover the current path portion 123 but not the cut portion 125.

[0116] The inventors of this invention conducted experiments to determine whether a short circuit occurs in the current path section 123 to which the reinforcing section 130 is attached when current flows through the blank positive electrode section 120 made of aluminum foil, and to determine the magnitude of the current when a short circuit occurs, as well as the possibility of short-circuiting depending on the width (size) of the current path section 123. For a current collector 100 for the positive electrode made of aluminum foil with a thickness of 12 μm, the experiment was conducted using OPP adhesive tape with a thickness of 60 μm as the reinforcing section 130. The laser conditions used to form the cut section 125 in the blank positive electrode section 120 were Loop: 1, Speed: 400, Power: 63%, Height: 18.2 cm.

[0117] (1) Experiment 1 In Experiment 1, the voltage and current were measured when the current path section 123 was short-circuited while gradually increasing the current flowing through the positive electrode plain section 120 made of aluminum metal foil. The results are shown in [Table 1] and [Table 2]. [Table 1] shows the results of 9 or 10 measurements when the reinforcing section 130 was attached to one side of the current path section 123 with widths of 1 mm, 3 mm, and 5 mm, and [Table 2] shows the results of 8 to 10 measurements when the reinforcing section 130 was attached to both sides of the current path section 123 with widths of 1 mm, 3 mm, and 5 mm.

[0118] [Table 1]

[0119] [Table 2]

[0120] Figures 18 and 19 are graphs showing the results of a short-circuit current experiment on the blank positive electrode portion of a fuse-integrated type according to one embodiment of the present invention. Figure 18 is a graph showing the results in [Table 1], and Figure 19 is a graph showing the results in [Table 2].

[0121] Referring to [Table 1] and Figure 18, it was found that when the current flowing through the positive electrode current collector 100 is gradually increased, a short circuit occurs when the width of the current path section 123, which has the reinforcing section 130 attached to only one side, is 1 mm, when the width is 3 mm, when the width is 17.6 A, and when the width is 5 mm, when the width is 19.3 A.

[0122] Referring to [Table 2] and Figure 19, when the current flowing through the positive electrode current collector 100 is gradually increased, a short circuit occurs when the width of the current path section 123, which has reinforcement sections 130 attached only to both sides, is 1 mm, when the width is 1 mm, a short circuit occurs when the average current flows at 14.5 A; when the width is 3 mm, a short circuit occurs when the average current flows at 17.7 A; and when the width is 5 mm, a short circuit occurs when the average current flows at 20.1 A.

[0123] It can be seen that the wider the current path section 123, the larger the current that causes a short circuit. It can also be seen that the difference in short-circuit current is not large when the reinforcing section 130 is attached to only one side compared to when it is attached to both sides.

[0124] (2) Experiment 2 In Experiment 2, the magnitude of the current flowing through the positive electrode plain section 120, which is made of aluminum metal foil, was used to determine whether or not a break in the current path section 123 occurred, and whether or not smoke and fire occurred in the reinforcement section 130.

[0125] Table 3 shows the results of measurements to determine whether the current path section breaks, emits smoke, and catches fire when a reinforcing part 130 is attached to one side of a current path section 123 with widths of 1 mm, 3 mm, and 5 mm, and the current is increased by 5 A increments from 5 to 65 A. Table 4 shows the results of measurements to determine whether the current path section breaks, emits smoke, and catches fire when a reinforcing part 130 is attached to both sides of a current path section 123 with widths of 1 mm, 3 mm, and 5 mm, and the current is increased by 5 A increments from 5 to 65 A. The results in Tables 3 and 4 are the results of measurements taken on a positive terminal blank section 120 with a length (vertical) of 50 mm and a width (horizontal) of 20 mm.

[0126] In the following Tables 3 through 8, × means that the fuse function does not work because the current path is not disconnected, and ○ means that the fuse function works because the current path is disconnected.

[0127] [Table 3]

[0128] Referring to [Table 3], when the reinforcing part 130 was attached to only one side of the current path section 123, a current path section with a width of 1 mm experienced disconnection when currents of 15A, 20A, and 25A flowed, but there was no smoke or fire. A current path section with a width of 3 mm experienced disconnection when currents of 20-50A flowed, smoke was emitted when currents of 20A and 25A flowed, and fire (sparks) occurred when currents of 30-40A flowed. A current path section with a width of 5 mm experienced disconnection when currents of 40-65A flowed, smoke was emitted when currents of 45A flowed, and fire (sparks) occurred when currents of 50A and 55A flowed. Furthermore, when the reinforcing part 130 was changed from OPP tape to polyimide tape, no sparks or smoke were generated.

[0129] [Table 4]

[0130] Referring to [Table 4], when the reinforcing parts 130 were attached to both sides of the current path section 123, the current path section with a width of 1 mm experienced disconnection when currents of 20 A and 25 A flowed, and smoke was emitted when a current of 20 A flowed, but no fire occurred. The current path section with a width of 3 mm experienced disconnection when currents of 30 to 60 A flowed, smoke was emitted when currents of 30 to 40 A flowed, and fire (sparks) occurred when a current of 45 A flowed. The current path section with a width of 5 mm experienced disconnection when currents of 35 to 65 A flowed, fire (sparks) occurred when currents of 35 to 55 A flowed, and no fire occurred when currents of 0 A and 55 A flowed.

[0131] (3) Experiment 3 In Experiment 3, the magnitude of the current flowing through the positive electrode plain section 120, which is made of aluminum metal foil, was used to confirm whether a break in the current path section 123 in the configuration shown in Figure 7 occurred, and whether the reinforcing section 130 emitted smoke and ignited (see Table 5). The same was confirmed as to whether a break in the current path section 123 in the configuration shown in Figure 11 occurred, and whether the reinforcing section 130 emitted smoke and ignited (see Table 6).

[0132] Table 5 shows the results of measuring whether the current path section breaks, emits smoke, and ignites when a current of 5 to 40A flows, with the current increasing by 5A at a time, for a current path section 123 with a width of 1mm and reinforcement sections 130 attached to both sides. Table 6 shows the results of measuring whether the current path section breaks, emits smoke, and ignites when a current of 5 to 25A flows, with the current increasing by 5A at a time, for a current path section 123 with a cut section length (L4) of 1mm and reinforcement sections 130 attached to both sides. The results in Tables 5 and 6 are measurements taken on a positive electrode blank section 120 with a length (vertical) of 50mm and a width (horizontal) of 20mm.

[0133] [Table 5]

[0134] Referring to [Table 5], when reinforcing parts 130 were attached to both sides of a current path section 123 with a width of 1 mm, a break in the wire occurred when a current of 20 to 40 A flowed, but no smoke or fire occurred in the reinforcing parts 130. Furthermore, the reinforcing parts 130 maintained their normal shape at all current values ​​from 5 to 40 A.

[0135] [Table 6]

[0136] Referring to [Table 6], when reinforcing parts 130 were attached to both sides of a current path section 123 with a width of 1 mm, a break in the wire occurred when a current of 10 to 25 A flowed, but no smoke or fire occurred in the reinforcing parts 130. Furthermore, the reinforcing parts 130 maintained their normal shape at all current values ​​from 5 to 25 A, and the current path section 123 also maintained its normal shape.

[0137] Referring to the results in [Table 1] to [Table 6], it can be seen that the electrode current collector 100 equipped with a fuse-integrated blank section according to the present invention can perform a fuse function that interrupts short-circuit current by forming a current path section 123 with a width of 1 to 5 mm on the blank section 120, and that safety can also be ensured by attaching a reinforcing section 130 to at least one side of the current path section 123.

[0138] (4) Experiment 4 In Experiment 4, we checked whether the current path portion 123 of the positive electrode plain portion 120, which is made of aluminum metal foil, would be cut when it was bent at 180 degrees. [Table 7] shows the experimental results when the reinforcing portion 130 was attached to one side of the current path portion with widths of 1 mm, 3 mm, and 5 mm, and [Table 8] shows the experimental results when the reinforcing portion 130 was attached to both sides of the current path portion with widths of 1 mm, 3 mm, and 5 mm.

[0139] [Table 7]

[0140] Referring to [Table 7], when the width of the current path was 1 mm, it was cut completely in 10 experiments. When the width of the current path was 3 mm, it was cut in 4 out of 9 experiments, but not in 5, and current flowed even when it was repeatedly folded more than 10 times. When the width of the current path was 5 mm, it was cut only once out of 9 experiments, not in the remaining 8, and current flowed even when it was repeatedly folded more than 10 times.

[0141] [Table 8]

[0142] Referring to [Table 8], when reinforcing parts were attached to both sides of the current path, the current path sections with widths of 1 mm, 3 mm, and 5 mm were not cut, and current flowed even when repeatedly folded more than 10 times.

[0143] Comparing the results in [Table 7] and [Table 8], it can be seen that when the reinforcement is attached to only one side of the current path, the greater the width of the current path, the greater the strength or rigidity. Furthermore, when the reinforcement is attached to both sides of the current path, it can be seen that the strength or rigidity of the current path can be sufficiently maintained.

[0144] Furthermore, the secondary battery 1 according to one embodiment of the present invention shown in Figures 1 and 2 may include electrode current collectors 100 and 200 equipped with the fuse-integrated blank sections 120 and 220 described above.

[0145] As described above, one embodiment of the present invention has been explained using examples and drawings that limit specific elements and other details. However, these are provided only to aid in the general understanding of the present invention, and the present invention is not limited to the above-described embodiment. A person with ordinary skill in the art to which the present invention belongs can make various modifications and variations from this description. Therefore, the spirit of the present invention should not be limited to the described embodiment, and not only the claims described later, but also all variations that are equivalent or equivalent to these claims, can be said to fall within the scope of the spirit of the present invention.

Claims

1. Electrode plates made of metal material to which an electrode active material is applied or coated; and A blank area formed at one end of the electrode plate where the electrode active material is absent; The plain area is, The current path portion is formed such that the widthwise length of the plain portion is narrower or shorter than that of other portions, and the current path portion includes an incision formed on one side of the current path portion so that the plain portion is absent. A fuse-integrated current collector for an electrode, characterized in that a reinforcing portion is attached to at least one of the two surfaces of the plain portion, either so as to cover at least one of the current path portion or the cut portion, or so as not to cover all or part of the current path portion.

2. The electrode current collector comprising a fuse-integrated plain portion according to claim 1, characterized in that at least one of the cut portions or current path portions is formed along the width direction of the plain portion.

3. The electrode current collector having a fuse-integrated blank portion, characterized in that the length of the current path portion in the width direction of the blank portion is formed to be shorter than the width or length of the cut portion, as described in claim 2.

4. The current path portion is formed to be connected to either one end of the blank portion in the width direction, or is formed in the central portion so as not to be connected to either one end of the blank portion in the width direction, as described in claim 3, for an electrode current collector having a fuse-integrated blank portion.

5. The aforementioned incision is, The electrode current collector having a fuse-integrated blank portion, characterized in that it is formed on at least one side of the current path portion along the width direction of the blank portion, or formed in the form of a hole between the current path portions, as described in claim 3.

6. The electrode current collector comprising a fuse-integrated blank portion, characterized in that the cut portion or the current path portion is formed near the edge of the electrode plate, as described in claim 5.

7. The electrode current collector having a fuse-integrated plain portion, characterized in that the cut portion is formed such that the reinforcing portion is provided on or attached to at least one of the two surfaces of the plain portion.

8. The current collector for an electrode having a fuse-integrated blank portion, characterized in that the cut portion is formed by removing the blank portion using a laser while the reinforcing portion is provided on or attached to at least one of the two surfaces of the blank portion.

9. The current collector for an electrode having a fuse-integrated plain section, characterized in that the reinforcing section is provided by a transparent tape through which light or a laser passes.

10. The aforementioned reinforcing portion is The current path portion is covered, but the incision portion is not covered, or The electrode current collector according to claim 7, characterized in that it is provided with a length corresponding to the width of the plain portion so as to integrally cover the current path portion and the cut portion.

11. The electrode current collector according to claim 7, characterized in that the reinforcing portion is provided with heat-resistant tape.

12. A secondary battery comprising the electrode current collector described in claim 7.

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