An electrode assembly including an electrode tape having a moisture absorption layer, and a secondary battery including the same

Abstract

The present specification relates to an electrode assembly including an electrode tape having a moisture absorbing layer, and a secondary battery including the same.

Description

Technical Field

[0001] This application claims the benefit of the filing date of Korean Patent Application No. 10-2022-0045598, filed with the Korean Intellectual Property Office on April 13, 2022, and all of its contents are incorporated herein by reference.

[0002] The present invention relates to an electrode assembly including an electrode tape having a moisture absorption layer, and a secondary battery including the same.

Background Art

[0003] In recent years, the demand for portable electronic products such as notebook computers, video cameras, and mobile phones has increased rapidly. As the development of electric vehicles, energy storage batteries, robots, satellites, etc. has become full-scale, many studies have been conducted on secondary batteries used as their driving power sources.

[0004] Such secondary batteries include, for example, nickel cadmium batteries, nickel metal hydride batteries, nickel zinc batteries, lithium secondary batteries, etc. Among these, lithium secondary batteries have almost no memory effect, can be charged and discharged freely, have a very low self-discharge rate, a high operating voltage, and a high energy density per unit weight compared to nickel-based secondary batteries, and are widely used in the field of advanced electronic devices.

[0005] Generally, a lithium secondary battery is configured by incorporating an electrode assembly composed of a positive electrode, a negative electrode, and a separator interposed between the positive electrode and the negative electrode, which is laminated or wound, into a case of a metal can or a laminate sheet, and injecting or impregnating an electrolytic solution therein.

[0006] The electrode assembly of the positive electrode / separator / negative electrode structure constituting the secondary battery is roughly classified into a jelly roll type (winding type) and a stack type (lamination type) according to its structure. The jelly roll type has a structure in which a separator is wound between a long sheet-type positive electrode and negative electrode coated with an active material, and the stack type has a structure in which a large number of positive electrodes and negative electrodes of a predetermined size are sequentially laminated with a separator interposed therebetween. Among them, the jelly roll type electrode assembly has the advantages of being easy to manufacture and having a high energy density per unit weight.

[0007] However, when moisture is present inside the cell or near the electrodes, the secondary battery has problems such as gas generation, deterioration of high-temperature storage performance and cycle performance, and is prone to deformation in the core part, resulting in damage to the separator and causing a short circuit.

[0008] In order to overcome such problems, there is a need for research on secondary batteries that can more effectively remove moisture inside the cell and in the electrode part while preventing deformation of the core part.

Summary of the Invention

Problems to be Solved by the Invention

[0009] This specification provides an electrode assembly including an electrode tape having a moisture-absorbing layer that adsorbs moisture in the battery, and a secondary battery including the same.

Means for Solving the Problems

[0010] One embodiment of the present invention is an electrode assembly having an electrode laminate including a positive electrode; a negative electrode; and a separator provided between the positive electrode and the negative electrode, wherein the positive electrode includes a positive electrode coating portion provided with a positive electrode active material layer and a positive electrode non-coated portion where the positive electrode active material is not applied, the negative electrode includes a negative electrode coating portion provided with a negative electrode active material layer and a negative electrode non-coated portion where the negative electrode active material layer is not applied, and includes an electrode tape that wraps at least one end portion of the positive electrode in the long side direction, the electrode tape includes an adhesive layer; and a moisture absorption layer provided on one surface of the adhesive layer that adsorbs moisture, one surface of the adhesive layer located in the direction where the moisture absorption layer is provided includes a first uneven surface for increasing adhesion, and the surface of the moisture absorption layer includes a second uneven surface for increasing the surface area, and provides an electrode assembly.

[0011] One embodiment of the present invention provides a secondary battery including the electrode assembly.

Effects of the Invention

[0012] The electrode assembly according to one embodiment of the present invention is characterized by including an electrode tape that wraps at least one end portion of the positive electrode in the long side direction. Specifically, the electrode tape includes a moisture absorption layer that adsorbs moisture, can effectively remove moisture inside the battery, can remove moisture near the electrodes from the electrode taping process, and can minimize the influence of moisture on high-nickel series batteries that are vulnerable to moisture. When removing moisture from the electrodes as described above, generation of HF can be minimized to prevent gas generation, overvoltage can be prevented, and high-temperature storage performance and cycle performance can be improved.

[0013] In particular, by providing the electrode tape in a form that wraps at least one end portion of the positive electrode in the long side direction, moisture inside the battery can be removed, and damage to the separator caused by burrs during deformation of the core of the electrode laminate can be effectively prevented, and curling of the positive electrode non-coated portion can be prevented.

[0014] In addition, the electrode tape provided in a form that wraps at least one side end portion in the long side direction of the positive electrode has a concavo-convex surface on one side of the adhesive layer, so that the adhesion force with the moisture absorption layer or the polymer resin layer can be increased. Therefore, the peeling of the moisture absorption layer can be minimized, moisture can be removed more stably, and damage to the separator due to burrs can be effectively prevented.

Brief Description of the Drawings

[0015]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Explanation of Reference Numerals

[0016] 10 ··· Adhesive layer 11 ··· First concavo-convex surface 20 ··· Moisture absorption layer 21 ··· Second concavo-convex surface 30 ··· Polymer resin layer 100 ··· Positive electrode 100a ··· Positive electrode non-coated portion 100b ··· Positive electrode coating portion 101 ··· Positive electrode tab 300 ··· Electrode tape 400 ··· End portion of the positive electrode

Best Mode for Carrying Out the Invention

[0017] Hereinafter, this specification will be described in more detail.

[0018] In this specification, when a certain part "includes" a certain component, this means that, unless otherwise stated to the contrary, it does not exclude other components, but may further include other components.

[0019] In this specification, when a certain member is located "above" another member, this includes not only the case where a certain member is in contact with another member, but also the case where another member exists between the two members.

[0020] In this specification, when a certain member is located side by side with another member, this may include the case where a certain member is located parallel to another member, but does not specify the angle formed between a certain member and another member.

[0021] In this specification, when a certain part is connected to another part, this includes not only the case where they are directly connected, but also the case where they are indirectly connected with other elements interposed therebetween.

[0022] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the embodiments of the present invention can be modified in various forms, and the scope of the present invention is not limited to the embodiments described below. However, when it is determined that a detailed description of related known functions or configurations may unnecessarily obscure the gist of the present invention in explaining the operating principle of the preferred embodiments of the present invention, the detailed description thereof will be omitted. Note that the same reference numerals are used for parts having similar functions and actions throughout the drawings.

[0023] And in describing the present invention, a detailed description of related known technologies that may unnecessarily obscure the gist of the present invention is omitted.

[0024] One embodiment of the present invention is an electrode assembly having an electrode laminate including a positive electrode, a negative electrode, and a separator provided between the positive electrode and the negative electrode, wherein the positive electrode includes a positive electrode coating portion provided with a positive electrode active material layer and a positive electrode bare portion where the positive electrode active material is not coated, the negative electrode includes a negative electrode coating portion provided with a negative electrode active material layer and a negative electrode bare portion where the negative electrode active material layer is not coated, and includes an electrode tape that wraps at least one end portion in the long side direction of the positive electrode, the electrode tape including an adhesive layer and a moisture-absorbing layer provided on one surface of the adhesive layer for adsorbing moisture, one surface of the adhesive layer located in the direction where the moisture-absorbing layer is provided includes a first uneven surface for enhancing adhesion, and the surface of the moisture-absorbing layer includes a second uneven surface for enhancing the surface area, and provides an electrode assembly.

[0025] Generally, in a secondary battery, moisture management is positioned as a major quality control item. In fact, moisture also causes side reactions inside the battery, which has a fatal impact on the performance and safety of the battery. When moisture exists inside the battery or near the electrodes, there are problems such as gas generation, deterioration of high-temperature storage performance and cycle performance, and deformation is likely to occur in the core part, resulting in damage to the separator and causing a short circuit.

[0026] However, due to various factors in the processes of material storage, dry room, battery manufacturing, etc., it is inevitable that a small amount of moisture is contained in the secondary battery. Even if management such as moisture measurement is carried out, it is difficult to remove the already-inflowed moisture again, so there is a problem that the overall performance of the secondary battery deteriorates.

[0027] In the present invention, a moisture-absorbing layer is introduced into the electrode tape used for the electrode, which is a direct part involved in the reaction of the battery, and is provided so as to wrap the end portion of the electrode, thereby removing moisture inside the battery and minimizing side reactions inside the battery, preventing deformation of the core part and damage to the separator, and preventing curling of the positive electrode bare portion, and improving the battery performance.

[0028] The electrode assembly according to an embodiment of the present invention may include an electrode tape that wraps at least one end portion on the long side direction of the positive electrode.

[0029] In one embodiment of the present invention, the electrode tape may include an adhesive layer; and a moisture-absorbing layer provided on one surface of the adhesive layer for adsorbing moisture.

[0030] In one embodiment of the present invention, one surface of the adhesive layer located in the direction where the moisture-absorbing layer is provided may include a first uneven surface for enhancing the adhesive force.

[0031] Specifically, when the electrode tape has a moisture-absorbing layer, delamination with the adhesive layer is likely to occur. Therefore, one surface of the adhesive layer located in the direction where the moisture-absorbing layer is provided may include an uneven surface in order to enhance the adhesive force with the adhesive layer. Thus, even if the moisture-absorbing layer adsorbs moisture, the adhesive force is maintained by the uneven surface of the adhesive layer and the moisture-absorbing layer does not peel off, so that a continuous moisture-absorbing effect and an end protection effect of the electrode tape can be expected.

[0032] In one embodiment of the present invention, the surface of the moisture-absorbing layer may include a second uneven surface for increasing the surface area. By including the second uneven surface in the moisture-absorbing layer, the surface area capable of adsorbing moisture can be increased, and moisture in the battery can be more effectively removed.

[0033] FIG. 1 shows a cross-sectional view of an electrode tape having an adhesive layer and a moisture-absorbing layer according to an embodiment of the present invention. Specifically, the electrode tape is provided with a moisture-absorbing layer 20 for adsorbing moisture on one surface of the adhesive layer 10, and a first uneven surface 11 for enhancing the adhesive force may be provided on one surface of the adhesive layer 10 located in the direction where the moisture-absorbing layer 20 is provided. Also, the surface of the moisture-absorbing layer 20 may include a second uneven surface 21 for increasing the surface area. In one example, the moisture-absorbing layer 20 may be provided in contact with the adhesive layer 10.

[0034] In one embodiment of the present invention, an additional layer may be provided between the adhesive layer and the moisture-absorbing layer to enhance physical strength. For example, one or more polymer resin layers may be further provided between the adhesive layer and the moisture-absorbing layer.

[0035] Referring to FIG. 2, a moisture-absorbing layer 20 that adsorbs moisture may be provided on one surface of the adhesive layer 10, and a polymer resin layer 30 may be provided between the adhesive layer 10 and the moisture-absorbing layer 20. That is, a polymer resin layer 30 may be provided in contact with one surface of the adhesive layer 10, and the moisture-absorbing layer 20 may be provided in contact with the other surface of the polymer resin layer 30 that faces the surface where the adhesive layer 10 is provided in contact. At this time, one surface of the adhesive layer 10 located in the direction where the polymer resin layer 30 is provided may include a first uneven surface 11, and the surface of the moisture-absorbing layer 20, that is, one surface of the moisture-absorbing layer 20 exposed to the air, may include a second uneven surface 21.

[0036] In FIG. 2, only one polymer resin layer 30 is shown, but the polymer resin layer may further include one or more layers.

[0037] The polymer resin layer may include at least one selected from the group consisting of polyimide resin, polyacrylate resin, thermoplastic polyurethane (TPU) resin, polyvinyl chloride resin, polyethylene terephthalate resin, polyethylene resin, polypropylene resin, polyamide resin, polycarbonate resin, and polystyrene resin. Specifically, the polymer resin layer may include polyimide resin. However, it is not limited thereto, and various commonly used polymer resin layers can be used without limitation.

[0038] The thickness of the polymer resin layer is 10 μm to 40 μm, and specifically, it may be 20 μm to 30 μm.

[0039] As described above, even when the electrode tape has a structure of three or more layers, delamination is likely to occur between the polymer resin layer provided with the moisture absorption layer and the adhesive layer. Therefore, in order to increase the adhesion force between the polymer resin layer and the adhesive layer, in the adhesive layer, one surface of the adhesive layer located in the direction in which the moisture absorption layer is provided may include an uneven surface. Therefore, even if the moisture absorption layer adsorbs moisture, the adhesion force is maintained by the uneven surface of the adhesive layer, the polymer resin layer is not peeled off, and the moisture absorption layer is not peeled off, so that a continuous moisture absorption effect of the electrode tape can be expected.

[0040] Also, in order to increase the adhesion force between the polymer resin layer and the moisture absorption layer, in the polymer resin layer, one surface of the polymer resin layer located in the direction in which the moisture absorption layer is provided may include a third uneven surface. Therefore, by introducing uneven surfaces into both the adhesive layer and the polymer resin layer to prevent peeling of the moisture absorption layer, the continuous moisture absorption effect of the electrode tape can be further improved.

[0041] In one embodiment of the present invention, the form of the uneven surface (the first uneven surface, the second uneven surface, or the third uneven surface) is not specified, and any form for expanding the surface area may be used. For example, it can be formed regularly in a pattern, or it can be formed irregularly with a non-constant height.

[0042] The uneven surface may include a wavy pattern, a lattice pattern, an embossed pattern in a positive engraving form, or an anchor pattern.

[0043] The wavy pattern can mean a pattern formed by a wavy curve. At this time, the wavy curve can form a convex portion or a concave portion. By including such a wavy pattern in the uneven surface, the surface area can be expanded to improve the adhesion force or increase the moisture absorption effect.

[0044] The lattice pattern can mean a pattern formed by convex portions where linear concave portions intersect. Alternatively, it can mean a pattern formed by concave portions where linear convex portions intersect. At this time, the formed convex or concave portion forms one lattice, and the shape of each lattice may be any of a square, a rectangle, a parallelogram, and a rhombus. By including the uneven surface having the lattice pattern as described above, the surface area can be increased to improve the adhesion force or the moisture absorption effect can be increased.

[0045] Referring to FIG. 3, the surface of the moisture absorption layer 20, that is, one surface of the moisture absorption layer 20 exposed to the air includes a second uneven surface 21, and the second uneven surface 21 may include a lattice pattern. Although not shown in FIG. 3, other uneven surfaces included in the electrode tape may also have the lattice pattern.

[0046] The angle θ formed by each inclined surface of the convex portion in the lattice pattern is 110° to 150°, preferably 110° to 130° or may be 120°. The lower the angle, the more advantageous it is to secure the surface area. However, since the surface of the moisture absorption layer becomes sharp, the separation film in contact with the moisture absorption layer may be damaged. Therefore, when the angle between the inclined surfaces of the lattice pattern satisfies the above range, the moisture absorption layer can secure an appropriate surface area without damaging the separation film.

[0047] For example, when the angle formed by the inclined surface of the convex portion of the lattice pattern is 120°, it is possible to secure an additional area about 1.15 times the existing length.

[0048] The average distance between the convex portion and the concave portion may be 0.5 mm to 2.0 mm.

[0049] The embossed pattern with a positive engraving shape may be, for example, a pattern in which spherical irregularities protrude in the positive engraving shape. Referring to FIG. 4, on one side of the adhesive layer 10 located in the direction where the moisture absorption layer 20 is provided, the electrode tape may include a first uneven surface 11, and the first uneven surface 11 may include a pattern in which spherical irregularities protrude. By including the first uneven surface contained in the adhesive layer in such a pattern, the adhesion of the adhesive layer can be improved. Although not shown in FIG. 4, other uneven surfaces included in the electrode tape may also have the embossed pattern.

[0050] By including the embossed pattern as described above on the uneven surface, the surface area can be increased to improve the adhesion, or the moisture absorption effect can be increased.

[0051] The anchor pattern means a pattern formed by making a groove with an engraved shape on the surface. The groove with the engraved shape preferably has a thickness of 10% to 30% of the thickness of the layer where the pattern exists. By including the anchor pattern as described above on the uneven surface, the surface area can be increased to improve the adhesion, or the moisture absorption effect can be increased.

[0052] The adhesive layer may include an acrylate resin, but is not limited thereto, and various adhesive layer materials commonly used in the technical field can be appropriately adopted.

[0053] The thickness of the adhesive layer may be 10 μm to 40 μm or 15 μm to 25 μm.

[0054] The moisture absorption layer may include an adsorbent substance.

[0055] The adsorbent material can adsorb moisture and is not limited as long as it is electrochemically stable. Specifically, the adsorbent material may include one or more selected from the group including silica (SiO2) powder, metal powders such as alumina, alkaline earth metal oxides, metal oxides such as organometallic oxides, metal salts, phosphorus pentoxide (P2O5), BaTiO3, PMN-PT, hafnia (HfO2), SrTiO3, SnO2, CeO2, MgO, NiO, CaO, ZnO, ZrO2, Y2O3, Al2O3, TiO2, soda lime, amine-grafted zeolite, NaOH, Ca(OH)2, KOH, and the like. The adsorbent material is not limited to the aforementioned types, and various substances commonly used in the technical field can be appropriately adopted.

[0056] In one embodiment of the present specification, the adsorbent material may preferably be silica powder (SiO2). In the case of silica powder, it has the advantages of being very electrochemically stable, having a high moisture absorption rate, and being able to easily adsorb moisture while minimizing the influence on the battery reaction when located in the battery reaction region. In addition, it can provide economic efficiency with an inexpensive unit price.

[0057] The adsorbent material may be mixed with a binder. For example, after mixing the adsorbent material and the binder, it can be applied onto the polymer resin layer to form a moisture absorption layer. As the binder, an acrylate-based resin can be used, and it is not limited thereto. Various substances commonly used in the technical field can be appropriately adopted.

[0058] As described above, since the moisture absorption layer contains the adsorbent material, the moisture in the battery can be effectively removed, and the stability and performance of the battery can be increased.

[0059] The adsorbent may be contained in an amount of 5 to 50 parts by weight or 10 to 30 parts by weight based on the total weight of the moisture absorption layer. If the adsorbent is contained in an amount less than this range, it is insufficient to remove moisture in the battery. If it is contained in an excessive amount, there are problems such as insufficient flexibility of the tape and peeling / damage of the coating layer due to insufficient adhesiveness.

[0060] The thickness of the moisture absorption layer may be 10 to 40 μm or 15 to 25 μm.

[0061] The average thickness of the electrode tape is 20 to 100 μm, specifically 30 to 80 μm, and may also be 50 to 70 μm. However, the configuration of the electrode tape is not limited to this, and it varies depending on the size of the battery, and a configuration known in the technical field to which the present invention belongs can be appropriately adopted.

[0062] When the electrode tape is composed of a double layer of an adhesive layer and a moisture absorption layer, the thickness of the adhesive layer may be 40% to 60% of the total thickness of the electrode tape, and preferably 50%. Also, the thickness of the moisture absorption layer may be 40% to 60% of the total thickness of the electrode tape, and preferably 50%.

[0063] When the electrode tape is composed of a double layer of an adhesive layer and a moisture absorption layer, the thicknesses of the adhesive layer and the moisture absorption layer may be the same, and may each be 50% ± 10% of the total thickness of the electrode tape.

[0064] When the electrode tape is composed of a triple layer of an adhesive layer, a polymer resin layer, and a moisture absorption layer, the thickness of the adhesive layer is 20% to 40% of the total thickness of the electrode tape, and preferably may be 30% to 35%. Also, the thickness of the polymer resin layer is 20% to 40% of the total thickness of the electrode tape, and preferably may be 30% to 35%. Also, the thickness of the moisture absorption layer is 20% to 40% of the total thickness of the electrode tape, and preferably may be 30% to 35%.

[0065] When the electrode tape is composed of a triple layer of an adhesive layer, a polymer resin layer, and a moisture absorption layer, the thicknesses of the adhesive layer, the polymer resin layer, and the moisture absorption layer may be the same, or may each be 1 / 3 ± 10% of the total thickness of the electrode tape.

[0066] When the electrode tape is composed of an adhesive layer, n polymer resin layers (n ≥ 1), and an n + 2 layer of a moisture absorption layer, the thicknesses of the adhesive layer, the n polymer resin layers, and the moisture absorption layer may be the same, or may each be {1 / (n + 2)} ± 10% of the total thickness of the electrode tape.

[0067] The configuration of the electrode tape described above is not limited to this, and may vary depending on the size of the battery, and a configuration known in the technical field to which the present invention belongs can be appropriately adopted.

[0068] In one embodiment of the present invention, the electrode assembly may include a positive electrode; a negative electrode; and an electrode laminate including a separator provided between the positive electrode and the negative electrode, and may include an electrode tape that wraps at least one end portion in the long side direction of the positive electrode.

[0069] The electrode assembly includes an electrode laminate. The electrode laminate includes a positive electrode; a negative electrode; and a separator provided between the positive electrode and the negative electrode, and the separator separates the positive electrode and the negative electrode and electrically insulates them.

[0070] The electrode assembly may have a structure in which the electrode laminate is wound. Specifically, the positive electrode and the negative electrode may be wound together with the separator to form a jelly roll type electrode assembly. Alternatively, the electrode assembly may be formed in a stack type or a stack and folding type, etc.

[0071] The positive electrode may be composed of a positive electrode current collector and a positive electrode active material coated on the positive electrode current collector. Here, the positive electrode current collector may be made of, for example, a foil of aluminum (Al) material. At this time, the positive electrode active material may be made of, for example, lithium manganese oxide, lithium cobalt oxide, lithium nickel oxide, lithium iron phosphate, or a compound and mixture containing one or more of these.

[0072] The negative electrode may be composed of a negative electrode current collector and a negative electrode active material coated on the negative electrode current collector. Here, the negative electrode current collector may be made of, for example, a foil made of copper (Cu) or nickel (Ni) material. At this time, the negative electrode active material may be made of, as an example, a material containing artificial graphite. Also, as another example, the negative electrode active material may be made of lithium metal, lithium alloy, carbon, petroleum coke, activated carbon, graphite, silicon compound, tin compound, titanium compound or their alloys.

[0073] The separator is made of an insulating material and may be laminated alternately with the positive electrode and the negative electrode. Here, the separator can be located between the positive electrode and the negative electrode and on the outer surfaces of the positive electrode and the negative electrode.

[0074] Also, the separator may be made of a ductile material. At this time, the separator may be formed of, for example, a polyolefin resin film such as polyethylene or polypropylene having microporosity.

[0075] The positive electrode includes a positive electrode coating portion provided with a positive electrode active material layer and a positive electrode plain portion where the positive electrode active material layer is not provided.

[0076] The negative electrode includes a negative electrode coating portion provided with a negative electrode active material layer and a negative electrode plain portion where the negative electrode active material layer is not provided.

[0077] The electrode tab is attached to the positive electrode and / or the negative electrode and is electrically connected to the positive electrode and / or the negative electrode.

[0078] The electrode tab may be a positive electrode tab attached to the positive electrode or a negative electrode tab attached to the negative electrode.

[0079] The positive electrode tab may be provided on the positive electrode non-coated portion, and the negative electrode tab may be provided on the negative electrode non-coated portion.

[0080] In one embodiment of the present invention, the electrode tape may be provided so as to wrap at least one side end portion in the long side direction of the positive electrode. By providing the electrode tape so as to wrap one side end portion in the long side direction of the positive electrode, the end portion can be protected and moisture can be effectively removed, so that damage to the separation film due to burrs during deformation of the core of the electrode assembly can be effectively prevented.

[0081] FIG. 5 and FIG. 6 show an embodiment of the positive electrode provided with the above-described electrode tape. Specifically, the positive electrode 100 includes a positive electrode coating portion 100b provided with a positive electrode active material layer and a positive electrode non-coated portion 100a not provided with a positive electrode active material layer, and a positive electrode tab 101 may be provided on the positive electrode non-coated portion 100a. At this time, an electrode tape 300 may be provided so as to wrap the end portion (end portion 400 of the positive electrode) in the long side direction of the positive electrode. In one example, the electrode tape 300 may be in a form attached so as to wrap the end portion 400 of the positive electrode from one surface to the other surface of the positive electrode.

[0082] In one embodiment of the present invention, the electrode tape may be extended and attached so as to be provided also on the positive electrode tab located on the positive electrode non-coated portion.

[0083] The electrode tape may be attached so as to cover 10% or more of the area of the positive electrode non-coated portion on the surface of one side of the positive electrode where the electrode tab is located. Specifically, it can cover an area of 20% or less, an area of 50% or less, or an area of 90% or less.

[0084] Specifically, as shown in FIG. 7(a), the electrode tape 300 can be attached from the end portion 400 of the positive electrode across the entire non-coated portion 100a on one side of the positive electrode. Alternatively, as shown in FIG. 7(b), the electrode tape 300 may be attached to the non-coated portion 100a of the positive electrode that is 1 mm to 2 mm away from the positive electrode coating portion 100b in the direction of the positive electrode end portion. Or, as shown in FIG. 7(c), it may be attached to the non-coated portion 100a of the positive electrode that is 1 mm to 2 mm away from the end portion 400 of the positive electrode.

[0085] The electrode tape can wrap around and attach to the end portion of the positive electrode up to the other side of the positive electrode where the electrode tab is not located. Although not particularly shown in FIG. 7, the length of the electrode tape attached to the other side of the positive electrode may be the same as or different from the length of the electrode tape attached to one side of the positive electrode. When the length of the electrode tape attached to the other side of the positive electrode is different from the length of the electrode tape attached to one side of the positive electrode, the length of the electrode tape attached to the other side of the positive electrode may be longer or shorter than the length attached to the one side of the positive electrode where the electrode tab is located.

[0086] In one embodiment of the present invention, at least one end portion in the long side direction of the positive electrode provided with the electrode tape may be located in the non-coated portion of the positive electrode. That is, at least one end portion in the long side direction of the positive electrode can mean the end portion of the non-coated portion of the positive electrode.

[0087] The electrode tape may be further attached onto the positive electrode tab or the negative electrode tab. Also, the electrode tape may be further attached to a portion of the non-coated portion of the positive electrode where the positive electrode tab is not provided, or to a portion of the non-coated portion of the negative electrode where the negative electrode tab is not provided. Moreover, without being limited thereto, it can be further attached to a position vulnerable to moisture, such as the start end or the end of the electrode coating. In the case of a jelly roll type electrode assembly, it can be further attached to an acceptable non-coated portion within the outer diameter range to easily remove moisture inside the battery.

[0088] Even if the electrode tape is not the aforementioned electrode blank part, it can be further locally attached to a part that is locally vulnerable to moisture in the battery to enhance the moisture absorption effect. However, when additionally attaching to a part that is not the electrode blank part as described above, it must be locally attached to a part that does not affect the battery performance.

[0089] One embodiment of the present invention provides a secondary battery including the aforementioned electrode assembly. The secondary battery may be cylindrical, pouch-type, or square-shaped.

[0090] One embodiment of the present invention can provide a cylindrical secondary battery including the aforementioned electrode assembly.

[0091] The cylindrical secondary battery may have a structure in which an electrode assembly in which the aforementioned electrode laminate is wound is inserted into a cylindrical case together with an electrolytic solution.

[0092] One embodiment of the present invention can provide a pouch-type secondary battery including the aforementioned electrode assembly.

[0093] The pouch-type secondary battery may have a structure in which the aforementioned electrode assembly is inserted into a pouch-type case together with an electrolytic solution and includes a sealing part that is sealed at the edge of the pouch-type case.

[0094] As described above, the preferred embodiments of the present invention have been described. However, those skilled in the art in this technical field can understand that the present invention can be variously modified and changed without departing from the spirit and scope of the present invention described in the following claims.

Claims

1. An electrode assembly having an electrode laminate including a positive electrode, a negative electrode, and a separator provided between the positive electrode and the negative electrode, wherein the positive electrode includes a positive electrode coating portion provided with a positive electrode active material layer and a positive electrode bare portion where the positive electrode active material is not applied, the negative electrode includes a negative electrode coating portion provided with a negative electrode active material layer and a negative electrode bare portion where the negative electrode active material is not applied, including an electrode tape that wraps at least one end portion of the positive electrode in the long side direction thereof, the electrode tape includes an adhesive layer; and a moisture absorption layer provided on one surface of the adhesive layer for adsorbing moisture, one surface of the adhesive layer located in the direction where the moisture absorption layer is provided includes a first uneven surface for enhancing adhesion, and the surface of the moisture absorption layer includes a second uneven surface for increasing the surface area, the electrode assembly.

2. At least one end portion of the positive electrode provided with the electrode tape in the long side direction thereof is located in the positive electrode bare portion, the electrode assembly according to claim 1.

3. The electrode tape is attached in a form that wraps at least one end portion of the positive electrode from one surface to the other surface of the positive electrode, the electrode assembly according to claim 1.

4. The moisture absorption layer contains silica (SiO ２ ), the electrode assembly according to claim 1.

5. The first uneven surface or the second uneven surface includes a wavy pattern, a lattice pattern, or an embossed pattern of a positive engraving shape, the electrode assembly according to claim 1.

6. The first uneven surface or the second uneven surface includes a lattice pattern, the lattice pattern includes convex portions; and concave portions, and an average distance between the convex portions and the concave portions is 0.5 mm to 2.0 mm, the electrode assembly according to claim 1.

7. The second uneven surface includes a lattice pattern, The lattice pattern includes convex portions and concave portions; In the lattice pattern, the angle θ formed by each inclined surface of the convex portion is 110° to 150°. The electrode assembly according to claim 1.

8. The electrode assembly according to claim 1, further including one or more polymer resin layers between the adhesive layer and the moisture absorption layer.

9. One surface of the polymer resin layer located in the direction in which the moisture absorption layer is provided includes a third uneven surface for enhancing adhesion. The electrode assembly according to claim 8.

10. The electrode assembly includes a structure in which the electrode laminate is wound. The electrode assembly according to claim 1.

11. A secondary battery including the electrode assembly according to any one of claims 1 to 10.

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