Electrode assembly and secondary battery including the same

Abstract

The electrode assembly according to the present invention includes a positive electrode including a positive active material portion formed by stacking a positive active material on a positive current collector and a positive uncoated portion formed by not stacking the positive active material; a positive tab provided on the positive uncoated portion; a negative electrode including a negative active material portion formed by stacking a negative active material on a negative current collector and a negative uncoated portion formed by not stacking the negative active material; a negative tab provided on the negative uncoated portion; and a separator for insulating the positive electrode and the negative electrode, wherein the negative uncoated portion includes a core-side negative electrode uncoated portion that is positioned on a core when the positive electrode, the negative electrode, and the separator are wound up, and the negative electrode tab is positioned on one side of both sides of the core-side negative electrode uncoated portion that is the positive electrode side, and a protective tape is attached to the other side of the core-side negative electrode uncoated portion.

Description

[Technical field]

[0001] [CROSS REFERENCE TO RELATED APPLICATIONS] This application claims the benefit of priority based on Korean Patent Application No. 10-2020-0183971 filed on December 24, 2020, and all contents disclosed in the documents of that Korean patent application are incorporated herein by reference.

[0002] The present invention relates to an electrode assembly and a secondary battery including the same. [Background technology]

[0003] Unlike primary batteries, secondary batteries can be recharged and have the potential to be small and have large capacity, so they have been the subject of much research and development in recent years. With the development of technology and increasing demand for mobile devices, the demand for secondary batteries as an energy source is rapidly increasing.

[0004] Secondary batteries are classified into coin type batteries, cylindrical type batteries, prismatic type batteries, and pouch type batteries according to the shape of the battery case. The electrode assembly installed inside the battery case of the secondary battery is a power generating element that can be charged and discharged and has a laminated structure of electrodes and a separator.

[0005] Electrode assemblies can be roughly classified into a jelly-roll type in which a sheet-type positive electrode and a negative electrode coated with an active material are wound with a separator interposed between them, a stack type in which a number of positive electrodes and negative electrodes are stacked in sequence with a separator interposed between them, and a stack / folding type in which a stack-type unit cell is wound with a long separator film.

[0006] Among these, the jelly-roll type electrode assembly is widely used since it has advantages of being easy to manufacture and having a high energy density per weight.

[0007] However, there are problems with the conventional jelly-roll type electrode assembly, such as the contraction of the separator located in the core and the breakage of the separator at the end of the positive electrode core, which can cause fires.In addition, the conventional jelly-roll type electrode assembly structure has a problem with the core collapsing, which is important for the life characteristics of the secondary battery, resulting in a reduction in life. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Korean Patent Publication No. 10-2016-0010121 Summary of the Invention [Problem to be solved by the invention]

[0009] SUMMARY OF THE DISCLOSURE One aspect of the present invention is to provide an electrode assembly capable of preventing damage to a separator in a wound-type electrode assembly, and a secondary battery including the electrode assembly. [Means for solving the problem]

[0010] An electrode assembly according to an embodiment of the present invention is a roll-type electrode assembly, comprising: a positive electrode including a positive electrode active material portion formed by stacking a positive electrode active material on a positive electrode current collector and a positive electrode uncoated portion formed by not stacking the positive electrode active material; a positive electrode tab provided on the positive electrode uncoated portion; a negative electrode including a negative electrode active material portion formed by stacking a negative electrode active material on a negative electrode current collector and a negative electrode uncoated portion formed by not stacking the negative electrode active material; a negative electrode tab provided on the negative electrode uncoated portion; and and a separator that insulates the positive electrode and the negative electrode, the negative electrode uncoated portion may include a core-side negative electrode uncoated portion that is positioned on a core when the positive electrode, the negative electrode, and the separator are wound up, the negative electrode tab may be positioned on one side of the core-side negative electrode uncoated portion that is on the positive electrode side, and a protective tape may be attached to the other side of the core-side negative electrode uncoated portion, and the protective tape may be attached across end portions of the other side of the core-side negative electrode uncoated portion and the other side of the core-side negative electrode active material portion.

[0011] Meanwhile, a secondary battery according to an embodiment of the present invention may include the electrode assembly according to the embodiment of the present invention. Effect of the Invention

[0012] According to the present invention, a negative electrode tab is positioned on one side of the core-side negative electrode uncoated part, which is a positive electrode side, and a protective tape is attached to the other side of the core-side negative electrode uncoated part. The protective tape is attached across the other side of the core-side negative electrode uncoated part and the other side of the core-side negative electrode active material part, and when a separator facing the core-side end of the positive electrode is damaged during winding, a short circuit can be prevented via the protective tape. [Brief description of the drawings]

[0013] [Figure 1] 1 is a perspective view illustrating an electrode assembly and a secondary battery including the electrode assembly according to an embodiment of the present invention; [Diagram 2] 2 is a front view illustrating an electrode assembly according to an embodiment of the present invention in an unfolded state before being wound up; [Diagram 3] 11 is a front view illustrating an electrode assembly according to another embodiment of the present invention in an unfolded state before being wound up; FIG. [Figure 4] 4 is a graph showing the measurement of ignition stability of electrode assemblies according to the prior art and an embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] The object, particular advantages and novel features of the present invention will become more apparent from the following detailed description and preferred embodiments in conjunction with the drawings. In this specification, when the components in each drawing are given reference numbers, it should be noted that the same components are given the same numbers as much as possible even if they are displayed in other drawings. In addition, the present invention may be embodied in many different forms and is not limited to the embodiments described herein. In addition, in describing the present invention, detailed descriptions of related known technologies that may unnecessarily obscure the gist of the present invention will be omitted.

[0015] Electrode Assembly According to an Embodiment FIG. 1 is a perspective view showing an electrode assembly according to an embodiment of the present invention and a secondary battery including the same, and FIG. 2 is a front view showing an unfolded state of the electrode assembly according to an embodiment of the present invention before being wound up.

[0016] 1 and 2, an electrode assembly 100 according to an embodiment of the present invention is a roll-type electrode assembly 100, and includes a positive electrode 110 including positive electrode active material portions 112, 113 and a positive electrode uncoated portion 115, a positive electrode tab 171 provided on the positive electrode uncoated portion 115, a negative electrode 120 including negative electrode active material portions 122, 123 and a negative electrode uncoated portions 125, 126, a negative electrode tab 172 provided on the negative electrode uncoated portions 125, 126, and a separator 160 for insulating between the positive electrode 110 and the negative electrode 120.

[0017] Hereinafter, an electrode assembly according to an embodiment of the present invention will be described in more detail.

[0018] The electrode assembly 100 is a power generating element capable of charging and discharging, and has a structure in which the electrodes 130 and the separators 160 are assembled and stacked alternately. Here, the electrode assembly 100 may be formed in a form in which the electrodes 130 and the separators 160 are assembled alternately and wound up. In this case, the electrode assembly 100 may be wound into a cylindrical shape wound around a central axis C.

[0019] The electrode 130 may include a positive electrode 110 and a negative electrode 120. The separator 160 separates and electrically insulates the positive electrode 110 and the negative electrode 120.

[0020] The positive electrode 110 may include a positive electrode current collector 111, positive electrode active material portions 112 and 113 which are regions formed by stacking a positive electrode active material 114 on the positive electrode current collector 111, and a positive electrode uncoated portion 115 which is a region where the positive electrode active material is not stacked.

[0021] The positive electrode current collector 111 may be made of, for example, an aluminum foil.

[0022] The positive electrode active material 114 may be lithium manganese oxide, lithium cobalt oxide, lithium nickel oxide, lithium iron phosphate, or a compound or mixture containing at least one of these.

[0023] The positive electrode uncoated portion 115 may be located between both sides of the positive electrode 110 .

[0024] The negative electrode 120 may include a negative electrode current collector 121, negative electrode active material parts 122 and 123 which are regions formed by stacking a negative electrode active material on the negative electrode current collector 121, and negative electrode uncoated parts 125 and 126 which are regions where the negative electrode active material is not stacked.

[0025] The negative electrode current collector 121 may be, for example, a foil made of copper (Cu) or nickel (Ni).

[0026] The negative electrode active material 124 may be, for example, artificial graphite, lithium metal, lithium alloy, carbon, petroleum coke, activated carbon, graphite, silicon compound, tin compound, titanium compound, or an alloy thereof. In this case, the negative electrode active material may further include, for example, non-graphite-based SiO (silica) or SiC (silicon carbide).

[0027] Meanwhile, the negative electrode active material parts 122, 123 may be provided on both sides of the negative electrode current collector 121. In this case, the length of the negative electrode active material parts 122, 123 provided on the negative electrode current collector 121 on the positive electrode 110 side may be formed longer than the length of the positive electrode active material parts 112, 113. Here, for example, the length of the negative electrode active material part 122 provided on one side of the negative electrode current collector 121 on the positive electrode 110 side may be formed longer than the length of the negative electrode active material part 123 provided on the other side of the negative electrode current collector 121, but the present invention is not necessarily limited thereto.

[0028] The negative electrode uncoated portions 125, 126 may include a core-side negative electrode uncoated portion 125 that is positioned on a core when the positive electrode 110, the negative electrode 120, and the separator 160 are wound.

[0029] The core-side negative electrode uncoated portion 125 may be located on one side of the negative electrode 120 .

[0030] At this time, the negative electrode 120, the first separator 140, the positive electrode 110, and the second separator 150 may be wound up in a clockwise direction starting from one side.

[0031] Meanwhile, the negative electrode uncoated portions 125, 126 may further include an outer negative electrode uncoated portion 126 located on the other side of the negative electrode 120. That is, the negative electrode uncoated portions 125, 126 may include a core-side negative electrode uncoated portion 125 located on the core side I of the electrode assembly 100 and an outer negative electrode uncoated portion 126 located on the outside O of the electrode assembly 100 when the electrode assembly 100 is wound up.

[0032] On the other hand, the negative electrode 120 may be formed to be longer than the positive electrode 110 .

[0033] The separator 160 is made of an insulating material and can provide insulation between the positive electrode 110 and the negative electrode 120 .

[0034] In addition, the separator 160 may be, for example, a multilayer film made of microporous polyethylene, polypropylene, or a combination thereof, or a polymer film for a solid polymer electrolyte or a gel-type polymer electrolyte, such as polyvinylidene fluoride, polyethylene oxide, polyacrylonitrile, or polyvinylidene fluoride-hexafluoropropylene copolymer.

[0035] The separation membrane 160 may include a first separation membrane 140 and a second separation membrane 150 .

[0036] In this case, the electrode assembly 100 may be stacked in the order of the negative electrode 120, the first separator 140, the positive electrode 110, and the second separator 150 from the outermost side of the winding.

[0037] The first separator 140 and the second separator 150 may be formed to be longer than the positive electrode 110 and the negative electrode 120 .

[0038] The electrode tab 170 is attached to the electrode 130 and is electrically connected to the electrode 130 .

[0039] Meanwhile, the electrode tabs 170 may include a positive electrode tab 171 attached to the positive electrode 110 and a negative electrode tab 172 attached to the negative electrode 120 .

[0040] The positive electrode tab 171 may be provided on the positive electrode uncoated portion 115 and may be located on one side of the positive electrode 110 facing the second separator 150 .

[0041] The negative electrode tab 172 may be provided on the negative electrode uncoated portions 125 and 126, and may be located on one of both surfaces of the core-side negative electrode uncoated portion 125 that faces the positive electrode 110.

[0042] Meanwhile, the width of the negative electrode tab 172 may be, for example, 3 to 4 mm. More specifically, the width of the negative electrode tab 172 may be, for example, 3.5 mm, but the present invention is not necessarily limited to this.

[0043] Meanwhile, the electrode assembly according to an embodiment of the present invention may further include protective tapes 180 and 190 attached to the core-side negative electrode uncoated portion 125 .

[0044] The protective tapes 180 and 190 may be attached across the ends of the core-side negative electrode uncoated portion 125 and the core-side negative electrode active material portions 122 and 123 .

[0045] In addition, the protective tapes 180 and 190 may include, for example, a material such as PI (polyimide) or PET (polyethylene terephthalate). Here, the protective tapes 180 and 190 may include a base material and an adhesive layer applied to one surface of the base material. In this case, the base material may be made of a material such as PI or PET.

[0046] Furthermore, the protective tapes 180, 190 may include a first protective tape 190 attached across the ends of one side of the core side negative electrode uncoated portion 125 and one side of the core side negative electrode active material parts 122, 123, and a second protective tape 180 attached across the ends of the other side of the core side negative electrode uncoated portion 125 and the other sides of the core side negative electrode active material parts 122, 123.

[0047] The first protective tape 190 may include a first portion 191 attached to one surface of the core-side negative electrode uncoated portion 125 and a second portion 192 attached to an end portion of one surface of the core-side negative electrode active material parts 122, 123. In this case, the length L1 of the first protective tape 190 may be longer than the length a1 of one surface of the core-side negative electrode uncoated portion 125.

[0048] Here, the first portion 191 of the first protective tape 190 may be attached, for example, over a portion excluding the end of the core-side negative electrode uncoated portion 125. In this case, the first protective tape 190 may be attached, for example, from a section that is 6 mm from the end of the core-side negative electrode uncoated portion 125, but the present invention is not limited thereto.

[0049] Meanwhile, in the first protective tape 190, the first portion 191 may be attached to the entire other surface of the core-side negative electrode uncoated portion 125, as another example.

[0050] The second protective tape 180 may include a first portion 181 attached to the other surface of the core-side negative electrode uncoated portion 125 and a second portion 182 attached to end portions of the other surfaces of the core-side negative electrode active material parts 122 and 123. In this case, the length of the second protective tape 180 may be longer than the length of the other surface of the core-side negative electrode uncoated portion 125.

[0051] Here, in the second protective tape 180, the first portion 181 may be attached, for example, over a portion excluding an end of the core-side negative electrode uncoated portion 125. Meanwhile, in the second protective tape 180, the first portion 181 may be attached over the entire other surface of the core-side negative electrode uncoated portion 125, as another example.

[0052] Meanwhile, the second portion 192 of the first protective tape 190 and the second portion 182 of the second protective tape 180 may overlap the core side I end portion of the positive electrode 110 in the stacking direction (the up-down direction when referring to FIG. 2) of the electrode 130 and the separators 140, 150. In this case, the second portion 192 of the first protective tape 190 and the second portion 182 of the second protective tape 180 may overlap the core side I end portion of the positive electrode 110 by 1 to 3 mm or more in the stacking direction.

[0053] The length L1 of the first protective tape 190 may be, for example, 17 to 40 mm. Specifically, the length L1 of the first protective tape 190 may be, for example, 30 to 40 mm. More specifically, the length L1 of the first protective tape 190 may be, for example, 35 to 37 mm.

[0054] The length of the second protective tape 180 may be, for example, 17 to 25 mm. In this case, the protective tape 180 may be specifically formed to be, for example, 17 to 19 mm. Here, when the second protective tape 180 is formed to be 17 mm or more in length and wound up, it may be provided so that there is a portion overlapping with the core side I end of the positive electrode 110 in the lamination direction. In this way, when the second separator 150 is damaged by the core side I end of the positive electrode 110, the second protective tape 180 can prevent the core side I end of the positive electrode 110 from coming into contact with the negative electrode 120, causing a short circuit.

[0055] Meanwhile, for example, the attachment length of the first protective tape 190 and the second protective tape 180 attached to the core-side negative electrode uncoated portion 125 may be 13 mm, but the present invention is not limited thereto.

[0056] The electrode assembly according to an embodiment of the present invention having the above configuration can prevent a short circuit via the protective tapes 180, 190 when the separator 160 facing the core side I end of the positive electrode 110 is damaged. That is, the first protective tape 190 is positioned on one surface of the core side negative electrode uncoated portion 125 facing the core side I end of the positive electrode 110 across the first separator 140, and when the first separator 140 is damaged by the end of the positive electrode 110, the end of the positive electrode 110 comes into contact with the core side negative electrode uncoated portion 125, thereby preventing an electrical short circuit from occurring. In addition, when the electrode assembly 100 is wound up, the second protective tape 180 is positioned on the other side of the core-side negative electrode uncoated portion 125 that faces the core-side I end portion of the positive electrode 110 across the second separator 150, so that when the second separator 150 is damaged by the end of the positive electrode 110, the end of the positive electrode 110 can be prevented from coming into contact with the core-side negative electrode uncoated portion 125, thereby preventing an electrical short circuit from occurring.

[0057] In addition, since the protective tapes 180 and 190 are attached to the negative electrode uncoated portion 125 on the core side, it is possible to prevent the core side from collapsing, thereby preventing a decrease in the battery life.

[0058] Electrode assemblies according to other embodiments An electrode assembly 200 according to another embodiment will be described below.

[0059] FIG. 3 is a front view showing an electrode assembly according to another embodiment of the present invention in an unfolded state before being wound up.

[0060] 3, an electrode assembly 200 according to another embodiment of the present invention is a winding-type electrode assembly, and includes a positive electrode 110 including positive electrode active material portions 112, 113 and a positive electrode uncoated portion 115, a positive electrode tab 171 provided on the positive electrode uncoated portion 115, a negative electrode 120 including negative electrode active material portions 122, 123 and a negative electrode uncoated portions 125, 126, a negative electrode tab 172 provided on the negative electrode uncoated portions 125, 126, and a separator 160 providing insulation between the positive electrode 110 and the negative electrode 120.

[0061] The electrode assembly 200 according to another embodiment of the present invention is different from the electrode assembly according to the above-described embodiment in the embodiment of the protective tapes 280 and 290. Therefore, in this embodiment, the content that overlaps with the above-described embodiment will be omitted or briefly described, and the description will focus on the differences.

[0062] More specifically, the electrode assembly 100 has a structure in which the electrodes 130 and the separators 160 are assembled and stacked alternately. Here, the electrode assembly 100 may be formed in a form in which the electrodes 130 and the separators 160 are assembled alternately and wound up. In this case, the electrode assembly 100 may be wound into a cylindrical shape wound around a central axis C.

[0063] The electrode 130 may include a positive electrode 110 and a negative electrode 120. The separator 160 separates and electrically insulates the positive electrode 110 and the negative electrode 120.

[0064] The positive electrode 110 may include a positive electrode current collector 111, positive electrode active material portions 112 and 113 which are regions formed by stacking a positive electrode active material 114 on the positive electrode current collector 111, and a positive electrode uncoated portion 115 which is a region where the positive electrode active material is not stacked.

[0065] The positive electrode current collector 111 may be made of, for example, an aluminum foil.

[0066] The positive electrode uncoated portion 115 may be located between both sides of the positive electrode 110 .

[0067] The negative electrode 120 may include a negative electrode current collector 121, negative electrode active material parts 122 and 123 which are regions formed by stacking a negative electrode active material 124 on the negative electrode current collector 121, and negative electrode uncoated parts 125 and 126 which are regions where the negative electrode active material is not stacked.

[0068] The negative electrode current collector 121 may be, for example, a foil made of copper (Cu) or nickel (Ni).

[0069] Meanwhile, the negative electrode active material parts 122, 123 may be provided on both sides of the negative electrode current collector 121. In this case, the length of the negative electrode active material part 122 provided on the negative electrode current collector 121 on the positive electrode 110 side may be formed to be longer than the length of the positive electrode active material parts 112, 113.

[0070] The negative electrode uncoated portions 125 and 126 may include a core-side negative electrode uncoated portion 125 of the negative electrode 120 that is positioned on a core when the positive electrode 110, the negative electrode 120, and the separator 160 are wound.

[0071] The core-side negative electrode uncoated portion 125 may be located on one side of the negative electrode 120 .

[0072] At this time, the negative electrode 120, the first separator 140, the positive electrode 110, and the second separator 150 may be wound up in a clockwise direction starting from one side.

[0073] On the other hand, the negative electrode 120 may be formed to be longer than the positive electrode 110 .

[0074] The separator 160 is made of an insulating material and can provide insulation between the positive electrode 110 and the negative electrode 120 .

[0075] The separation membrane 160 may include a first separation membrane 140 and a second separation membrane 150 .

[0076] In this case, the electrode assembly 100 may be stacked in the order of the negative electrode 120, the first separator 140, the positive electrode 110, and the second separator 150 from the outermost side of the winding.

[0077] The first separator 140 and the second separator 150 may be formed to be longer than the positive electrode 110 and the negative electrode 120 .

[0078] The electrode tab 170 is attached to the electrode 130 and is electrically connected to the electrode 130 .

[0079] Meanwhile, the electrode tabs 170 may include a positive electrode tab 171 attached to the positive electrode 110 and a negative electrode tab 172 attached to the negative electrode 120 .

[0080] The positive electrode tab 171 may be provided on the positive electrode uncoated portion 115 and may be located on one side of the positive electrode 110 facing the second separator 150 .

[0081] The negative electrode tab 172 may be provided on the negative electrode uncoated portions 125 and 126, and may be located on one of both surfaces of the core-side negative electrode uncoated portion 125 that faces the positive electrode 110.

[0082] Meanwhile, the electrode assembly according to an embodiment of the present invention may further include protective tapes 280 and 290 attached to the core-side negative electrode uncoated portion 125 .

[0083] The protective tapes 280 and 290 may be attached across the ends of the core-side negative electrode uncoated portion 125 and the core-side negative electrode active material portions 122 and 123 .

[0084] The protective tapes 280, 290 may include a first protective tape 290 attached across the ends of one side of the core side negative electrode uncoated portion 125 and one side of the core side negative electrode active material parts 122, 123, and a second protective tape 280 attached across the ends of the other side of the core side negative electrode uncoated portion 125 and the other sides of the core side negative electrode active material parts 122, 123.

[0085] The first protective tape 290 may include a first portion 291 attached to one surface of the core-side negative electrode uncoated portion 125 and a second portion 292 attached to an end portion of one surface of the core-side negative electrode active material portions 122, 123. In this case, the length of the first protective tape 290 may be longer than the length of one surface of the core-side negative electrode uncoated portion 125.

[0086] Here, in the first protective tape 290, the first portion 291 may be attached, for example, over a portion excluding an end portion of the core-side negative electrode uncoated portion 125. Meanwhile, in the first protective tape 290, as another example, the first portion 291 may be attached over the entire one surface of the core-side negative electrode uncoated portion 125. In this case, the length of the first protective tape 290 may be longer than the length of one surface of the core-side negative electrode uncoated portion 125.

[0087] The second protective tape 280 may include a first portion 281 attached to the other surface of the core-side negative electrode uncoated portion 125 and a second portion 282 attached to end portions of the other surfaces of the core-side negative electrode active material parts 122, 123. In this case, the length L2 of the second protective tape 280 may be longer than the length a2 of the other surface of the core-side negative electrode uncoated portion 125.

[0088] Here, in the second protective tape 280, the first portion 281 may be attached, for example, over a portion excluding an end of the core-side negative electrode uncoated portion 125. Meanwhile, in the second protective tape 280, the first portion 281 may be attached over the entire other surface of the core-side negative electrode uncoated portion 125, as another example.

[0089] Meanwhile, the second portion 292 of the first protective tape 290 and the second portion 282 of the second protective tape 280 may overlap with the core side I end portion of the positive electrode 110 in the stacking direction (the up-down direction when referring to FIG. 3) of the electrode 130 and the separators 140, 150. In this case, the second portion 292 of the first protective tape 290 and the second portion 282 of the second protective tape 280 may overlap with the core side I end portion of the positive electrode 110 by 1 to 3 mm or more in the stacking direction.

[0090] The length of the first protective tape 290 may be, for example, 17 to 25 mm. In this case, the first protective tape 290 may be specifically formed to, for example, 17 to 19 mm. Here, the length of the first protective tape 290 may be formed to be 17 mm or more, and may be provided so as to have a portion overlapping with the core side I end of the positive electrode 110 in the stacking direction. In this way, when the first separator 140 is damaged by the core side I end of the positive electrode 110, the first protective tape 290 can prevent the core side I end of the positive electrode 110 from coming into contact with the negative electrode 120, causing a short circuit.

[0091] The length L2 of the second protective tape 280 may be, for example, 30 to 40 mm. Specifically, the length L2 of the second protective tape 280 may be, for example, 35 to 37 mm.

[0092] As a result, the length L2 of the second protective tape 280 is formed to be 37 mm or less, and the movement of lithium ions between the positive electrode 110 and the negative electrode 120 is not hindered, so that the performance of the battery is not degraded, and the diameter of the electrode assembly 200 is prevented from being excessively expanded.

[0093] In addition, when the length L2 of the second protective tape 280 is formed to be 35 mm or more and the core side end portion of the positive electrode 110 faces the second protective tape 280 after the core side I portion of the negative electrode 120 is wound twice, it is possible to have a portion overlapping with the core side I end portion of the positive electrode 110 in the stacking direction.

[0094] secondary battery Hereinafter, a secondary battery according to an embodiment of the present invention will be described.

[0095] 1, a secondary battery 10 according to an embodiment of the present invention includes an electrode assembly 100 and a battery case 20. The electrode assembly 100 is a wound-type electrode assembly in which a positive electrode 110, a separator 160, and a negative electrode 120 are alternately stacked and wound, and includes a positive electrode 110 including a positive electrode active material portion and a positive electrode uncoated portion, a positive electrode tab 171 provided in the positive electrode uncoated portion, a negative electrode including a negative electrode active material portion and a negative electrode uncoated portion, a negative electrode tab 172 provided in the negative electrode uncoated portion, and a separator 160 for insulating between the positive electrode 110 and the negative electrode. Here, the negative electrode uncoated portion may include a core-side negative electrode uncoated portion of the negative electrode that is located on a core when the positive electrode 110, the negative electrode, and the separator 160 are wound.

[0096] The secondary battery 10 according to the embodiment of the present invention relates to a secondary battery including the electrode assembly according to the above-described embodiment or an electrode assembly according to another embodiment. Therefore, in this embodiment, the overlapping content with the above-described embodiment will be omitted or briefly described, and the description will focus on the differences.

[0097] The secondary battery 10 according to the embodiment of the present invention includes an electrode assembly 100 and a battery case 20 in which the electrode assembly 100 is accommodated. In this case, the secondary battery 10 according to the embodiment of the present invention may further include an electrolyte solution accommodated inside the battery case 20.

[0098] The battery case 20 may have an opening at its upper portion to accommodate the electrode assembly 100. In this case, the battery case 20 may be formed in, for example, a cylindrical shape.

[0099] The secondary battery 10 according to the embodiment of the present invention may further include a cap 30 for covering the open receiving portion 21 of the battery case 20 .

[0100] The electrode tab 170 is attached to the electrode 130 and is electrically connected to the electrode 130 .

[0101] The electrode tabs 170 may include a positive electrode tab 171 attached to the positive electrode 110 and a negative electrode tab 172 attached to the negative electrode 120 .

[0102] 1, the positive electrode tab 171 may be formed in a direction in which the cap 30 is positioned, which is an upper direction, and the negative electrode tab 172 may be positioned in a lower direction, toward a bottom surface of the receiving part 21 of the battery case 20. In this case, the cap 30 connected to the positive electrode tab 171 may form a positive electrode terminal, and the lower part of the battery case 20 connected to the negative electrode tab 172 may form a negative electrode terminal. Here, the cap 30 and the battery case 20 may be insulated from each other.

[0103] The negative electrode tab 172 may be located on one of both sides of the core-side negative electrode uncoated portion, which is on the positive electrode 110 side.

[0104] Meanwhile, the secondary battery 10 according to the embodiment of the present invention may further include protective tapes 180 and 190 attached to the negative electrode uncoated portion 125 on the core side.

[0105] The protective tapes 180 and 190 may be attached across the ends of the core-side negative electrode uncoated portion 125 and the core-side negative electrode active material portions 122 and 123 .

[0106] FIG. 4 is a graph showing the measurement of the ignition stability of electrode assemblies according to the prior art and an embodiment of the present invention.

[0107] The graph shown in FIG. 4 shows the ignition stability of an electrode assembly A according to an embodiment of the present invention in which a protective tape is attached to the uncoated portion of a negative electrode core, and an electrode assembly B according to the prior art in which a protective tape is not attached to the uncoated portion of a negative electrode core.

[0108] 4 shows that the ignition stability was measured by placing secondary batteries equipped with the electrode assemblies according to the present invention and the prior art in a chamber, and then heating the chamber to about 130° C. At this time, the length of the protective tape provided in the electrode assembly A according to the embodiment of the present invention is 35 mm.

[0109] As shown in the graph of FIG. 4, the electrode assembly B according to the conventional technology, which does not have a protective tape attached, ignites after about 34 minutes, whereas the electrode assembly A according to the embodiment of the present invention, in which the protective tape is attached to the negative electrode core uncoated portion, does not ignite.

[0110] In conclusion, in the electrode assembly A according to the embodiment of the present invention, since the protective tape is attached to the negative electrode core uncoated portion, the occurrence of a short circuit is prevented, and the core collapse is prevented, so that the occurrence of a fire does not occur.

[0111] Although the present invention has been described in detail above through specific embodiments, this is for the purpose of specifically explaining the present invention, and the present invention is not limited thereto. It can be said that various implementations are possible within the technical concept of the present invention by those having ordinary skill in the art.

[0112] Moreover, the specific scope of protection of the invention should be made clear by the claims. [Explanation of symbols]

[0113] 10: Secondary battery 20: Battery case 21: Storage unit 30: Cap 100, 200: Electrode assembly 110: Positive electrode 111: Positive electrode current collector 112, 113: Positive electrode active material part 114: Positive electrode active material 115: Positive electrode uncoated part 120: Negative electrode 121:Negative electrode current collector 122, 123: Negative electrode active material part 124:Negative electrode active material 125: Core side negative electrode uncoated area 126: Outer negative electrode plain area 130: Electrode 140:First separation membrane 150:Second separation membrane 160: Separation membrane 170: Electrode tab 171: Positive electrode tab 172: Negative electrode tab 180, 280: Second protective tape 190, 290: First protective tape 181, 191, 281, 291: Part 1 182, 192, 282, 292: 2nd part C: Central axis I: Core side O: Outside

Claims

1. A winding-type electrode assembly, a positive electrode including a positive electrode active material portion which is a region formed by laminating a positive electrode active material on a positive electrode current collector, and a positive electrode uncoated portion which is a region where the positive electrode active material is not laminated; a positive electrode tab provided on the positive electrode uncoated portion; a negative electrode including a negative electrode active material portion which is a region formed by laminating a negative electrode active material on a negative electrode current collector, and a negative electrode uncoated portion which is a region where the negative electrode active material is not laminated; a negative electrode tab provided on the negative electrode uncoated portion; and a separator for insulating the positive electrode and the negative electrode; The negative electrode uncoated portion includes a core-side negative electrode uncoated portion that is positioned on a core when the positive electrode, the negative electrode, and the separator are wound up, The negative electrode tab is located on one surface of the core-side negative electrode uncoated portion, the one surface being the positive electrode side, The protective tape attached to the core-side negative electrode uncoated portion (except for the one having a width relatively wider than that of the negative electrode current collector) ) the protective tape is attached across the end portions of the core-side negative electrode uncoated portion and the core-side negative electrode active material portion, The protective tape comprises: a first protective tape attached across one surface of the core-side negative electrode uncoated portion and one surface of the core-side negative electrode active material portion; and a second protective tape attached across an end portion of the other surface of the core-side negative electrode uncoated portion and an end portion of the other surface of the core-side negative electrode active material portion, the first protective tape includes a first portion attached to one surface of the core-side negative electrode uncoated portion and a second portion attached to an end portion of one surface of the core-side negative electrode active material portion, The first portion is an electrode assembly attached to the entire surface of the core-side negative electrode uncoated portion.

2. A winding-type electrode assembly, a positive electrode including a positive electrode active material portion which is a region formed by laminating a positive electrode active material on a positive electrode current collector, and a positive electrode uncoated portion which is a region where the positive electrode active material is not laminated; a positive electrode tab provided on the positive electrode uncoated portion; a negative electrode including a negative electrode active material portion which is a region formed by laminating a negative electrode active material on a negative electrode current collector, and a negative electrode uncoated portion which is a region where the negative electrode active material is not laminated; a negative electrode tab provided on the negative electrode uncoated portion; and a separator for insulating the positive electrode and the negative electrode; The negative electrode uncoated portion includes a core-side negative electrode uncoated portion that is positioned on a core when the positive electrode, the negative electrode, and the separator are wound up, The negative electrode tab is located on one surface of the core-side negative electrode uncoated portion, the one surface being the positive electrode side, The protective tape attached to the core-side negative electrode uncoated portion (except for the one having a width relatively wider than that of the negative electrode current collector) ) the protective tape is attached across the end portions of the core-side negative electrode uncoated portion and the core-side negative electrode active material portion, The protective tape comprises: a first protective tape attached across one surface of the core-side negative electrode uncoated portion and one surface of the core-side negative electrode active material portion; and a second protective tape attached across an end portion of the other surface of the core-side negative electrode uncoated portion and an end portion of the other surface of the core-side negative electrode active material portion, the second protective tape includes a first portion attached to the other surface of the core-side negative electrode uncoated portion and a second portion attached to an end portion of the other surface of the core-side negative electrode active material portion, The first portion is an electrode assembly attached to the entire other surface of the core-side negative electrode uncoated portion.

3. The separation membrane includes a first separation membrane and a second separation membrane, The electrode assembly according to claim 1 or 2, wherein the negative electrode, the first separator, the positive electrode, and the second separator are stacked in this order from the outermost side of the winding.

4. The first separator and the second separator are formed to be longer than the positive electrode and the negative electrode, The electrode assembly of claim 3 , wherein the negative electrode is longer than the positive electrode.

5. The core-side negative electrode uncoated portion is located on one side of the negative electrode, The electrode assembly of claim 4 , wherein the negative electrode, the first separator, the positive electrode, and the second separator are wound in a clockwise direction starting from one side.

6. The negative electrode active material portion is provided on both sides of the negative electrode current collector, The electrode assembly of claim 4 , wherein the length of the negative electrode active material part provided on the surface of the negative electrode current collector on the positive electrode side is longer than the length of the positive electrode active material part.

7. The positive electrode uncoated portion is located between both sides of the positive electrode, The electrode assembly of claim 3 , wherein the positive electrode tab is located on one surface of the positive electrode that faces the second separator.

8. A secondary battery comprising the electrode assembly according to claim 1 .

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