Electrode assembly for secondary battery and lithium secondary battery including the same

Abstract

The present invention relates to an electrode assembly for a secondary battery. The electrode assembly has a structure in which a laminate including a sheet-like positive electrode, a sheet-like negative electrode, and a sheet-like separator positioned between the sheet-like positive electrode and the sheet-like negative electrode is wound, and the electron conductive tape is attached to an outer surface of the sheet-like negative electrode not facing the sheet-like positive electrode in a width direction of the sheet-like negative electrode perpendicular to a winding direction of the laminate at a portion corresponding to a winding end portion of the sheet-like positive electrode.

Description

Technical Field

[0001] Cross-reference to related applications

[0002] This application claims priority and benefit to Korean Patent Application No. 10-2023-0108378, filed with the Korean Intellectual Property Office on August 18, 2023, the disclosure of which is incorporated herein by reference in its entirety.

[0003] This disclosure relates to electrode assemblies for secondary batteries and lithium secondary batteries including the electrode assemblies. Background Technology

[0004] With technological advancements and increasing demand for mobile devices, the need for secondary batteries as energy sources has grown rapidly. In particular, secondary batteries have attracted considerable attention as energy sources for power-driven devices such as electric bicycles, electric vehicles, and hybrid electric vehicles, as well as for mobile devices such as mobile phones, digital cameras, laptops, and wearable devices.

[0005] Based on the shape of the battery casing, secondary batteries can be classified into: cylindrical batteries, which have electrode assemblies mounted in a cylindrical metal container; prismatic batteries, which have electrode assemblies mounted in a prismatic metal container; and pouch batteries, which have electrode assemblies mounted in a pouch-shaped box made of aluminum laminate. Among these secondary batteries, cylindrical batteries have the advantage of relatively large capacity and structural stability.

[0006] Electrode assemblies installed in a battery case are power generation devices capable of charging / discharging and comprising a stacked structure of positive / spacers / negative electrodes. Electrode assemblies are classified into wound, stacked, and stacked / folded types. Wound types are configured such that elongated sheet-shaped positive and negative electrodes with applied active material are wound together, wherein spacers are inserted between the elongated sheet-shaped positive and negative electrodes. Stacked types are configured such that multiple positive and negative electrodes of predetermined dimensions are sequentially stacked while spacers are inserted between the multiple positive and negative electrodes. Stacked / folded types are a combination of wound and stacked types. Among these electrode assemblies, wound electrode assemblies have the advantage of being the easiest to manufacture and having a high energy density per unit weight.

[0007] However, in recent years, the increased demand for high capacity and the increased load on the positive electrode have increased its brittleness. Therefore, as the strength of the positive electrode tip increases and charging / discharging proceeds, the force applied to the corresponding negative electrode tip increases, leading to the problem of negative electrode breakage.

[0008] However, when the negative electrode breaks, it is observed that the electrical connection is broken in the 1+1 junction structure, that is, when both the positive and negative electrodes have one junction structure, causing the operation of the lithium secondary battery that has not yet exhausted its lifespan to stop.

[0009] Therefore, there is a need to develop a lithium-ion secondary battery technology that can solve these problems. Summary of the Invention

[0010] Technical issues

[0011] Therefore, the object of this disclosure is to provide an electrode assembly for a secondary battery that can delay the disconnection of the negative electrode portion corresponding to the positive electrode end in an electrode assembly having a wound structure as the secondary battery is charged and discharged.

[0012] Another object of this disclosure is to provide an electrode assembly for a secondary battery, wherein the operation of the secondary battery will not stop even if the negative terminal of the secondary battery is disconnected from the positive terminal during charging and discharging.

[0013] Technical solution

[0014] According to one embodiment of the present invention, an electrode assembly for a secondary battery is provided.

[0015] The electrode assembly has the following structure: in the structure, a laminate including a sheet-shaped positive electrode, a sheet-shaped negative electrode, and a sheet-shaped separator inserted between the sheet-shaped positive electrode and the sheet-shaped negative electrode is wound up.

[0016] In this embodiment, the electronic conductive strip is attached to the outer surface of the negative sheet that does not face the positive sheet at a portion corresponding to the winding end of the positive sheet, along the width direction of the negative sheet perpendicular to the winding direction of the laminate.

[0017] The electronic conductivity band can have a value of 0.01 Ω / cm. 2 Up to 100 Ω / cm 2 It has resistance and can be elastic.

[0018] Specifically, the electronically conductive strip may have a structure in which an electronically conductive adhesive layer is formed on a substrate, and more specifically, the electronically conductive strip may be a single-sided strip or a double-sided strip in which an electronically conductive adhesive layer is formed on one or both surfaces of the substrate.

[0019] In this case, the electronically conductive adhesive layer may include a carbon material for imparting electronic conductivity.

[0020] This electronically conductive band can be, for example, a carbon ribbon.

[0021] Specifically, the electronic conductive strip can be attached to the outer surface of the sheet-like negative electrode along the width direction of the sheet-like negative electrode at a portion corresponding to the wound end of the sheet-like positive electrode, and specifically, the electronic conductive strip can be attached such that the edge of the wound end of the sheet-like positive electrode has an extension width of 0.5 mm to 35 mm on both sides.

[0022] Meanwhile, the length of the sheet-like negative electrode in the winding direction can be longer than the length of the sheet-like positive electrode in the winding direction, and the electrode assembly can have a structure in which the sheet-like positive electrode is wound such that it is located on the inside.

[0023] In addition, the electrode assembly can be an electrode assembly with a 1+1 tab structure, in which the tab-shaped positive electrode includes a positive electrode tab and the tab-shaped negative electrode includes a negative electrode tab.

[0024] In this case, the sheet-like positive electrode can be a free-edge positive electrode, wherein the uncoated portion of the positive electrode without a positive electrode active material layer is formed in the middle, and the positive electrode tab can be positioned on the uncoated portion of the positive electrode.

[0025] Furthermore, the sheet-like negative electrode may have the following structure: in the structure, the uncoated portion of the negative electrode without a negative electrode active material layer is formed on one or both sides, and the negative electrode tab is positioned on the uncoated portion of the negative electrode formed at the winding end.

[0026] On the other hand, according to another embodiment of this disclosure, a lithium secondary battery including an electrode assembly is also provided. Attached Figure Description

[0027] Figure 1 This is a cross-sectional view of the laminate before the electrode assembly is wound.

[0028] Figure 2 It is shown in Figure 1 A schematic diagram of the inner surface of the electrode assembly in a partially wound state.

[0029] Figure 3 It is shown in Figure 1 A schematic diagram of the outer surface of the electrode assembly in a partially wound state. Detailed Implementation

[0030] Throughout the specification, when a section is referred to as “including” or “containing” a component, unless otherwise stated, this means that the section may include other components, but does not exclude other components.

[0031] Throughout this specification, the terms “about” or “approximately” or “roughly” are intended to mean close to a specified numerical value or range with permissible error, and are intended to prevent any unreasonable or unfair use by any third party of the accurate or absolute numerical values ​​disclosed for the purpose of understanding this disclosure.

[0032] The terms “width,” “length,” and “width” used here are based on those defined in the specification.

[0033] Furthermore, throughout the instruction manual, when referred to as "plane," it means when viewing the target portion from above, and when referred to as "cross section," it means when viewing the target portion from one side of a vertically cut cross section.

[0034] Based on the above limitations, embodiments of the present disclosure will now be described in detail with reference to the accompanying drawings. However, parts irrelevant to the description will be omitted in order to clearly describe the present disclosure, and throughout the specification, the same reference numerals denote the same elements.

[0035] Furthermore, in the accompanying drawings, the dimensions and thicknesses of each element are arbitrarily illustrated for ease of description, and therefore, this disclosure is not necessarily limited to those dimensions and thicknesses illustrated in the drawings. In the accompanying drawings, the thicknesses of layers, regions, etc., are exaggerated for clarity. In the accompanying drawings, the thicknesses of some layers and regions are exaggerated for ease of description.

[0036] The accompanying drawings are provided for illustrative purposes only, and the invention is not limited thereto, but is defined only by the scope of the claims described below.

[0037] According to embodiments of this disclosure, an electrode assembly for a secondary battery is provided.

[0038] The electrode assembly has the following structure: in the structure, a laminate including a sheet-shaped positive electrode, a sheet-shaped negative electrode, and a sheet-shaped separator inserted between the sheet-shaped positive electrode and the sheet-shaped negative electrode is wound up.

[0039] In this embodiment, the electronic conductive strip is attached to the outer surface of the negative sheet that does not face the positive sheet at a portion corresponding to the winding end of the positive sheet, along the width direction of the negative sheet perpendicular to the winding direction of the laminate.

[0040] Figure 1 The illustration shows a cross-sectional view of the laminate before the electrode assembly is wound. Figure 2 The diagram shows that there are Figure 1 A schematic diagram of the inner surface of the electrode assembly in a partially wound state, and Figure 3 The diagram shows that there are Figure 1 A schematic diagram of the outer surface of the electrode assembly in a partially wound state.

[0041] Reference Figures 1 to 3 The electrode assembly 100 has the following structure in which a stack 100' including a sheet-shaped positive electrode 110, a sheet-shaped negative electrode 120 and a sheet-shaped spacer 130 inserted between the sheet-shaped positive electrode 110 and the sheet-shaped negative electrode 120 is wound.

[0042] Here, the length l2 of the sheet negative electrode 120 in the winding direction can be longer than the length l1 of the sheet positive electrode 110 in the winding direction.

[0043] In addition, the sheet-shaped positive electrode 110 can be wound in the direction of the arrow so that the sheet-shaped positive electrode 110 is located on the inner side.

[0044] In addition, the sheet-shaped positive electrode 110 may include a positive electrode contact 113, and the sheet-shaped negative electrode 120 may include a negative electrode contact 123.

[0045] Although not limited to this, in the case of an electrode assembly having a 1+1 tab structure where each electrode includes a tab, if a short circuit occurs at the end of the positive electrode due to the charging and discharging of the secondary battery, the negative electrode tab will break and the operation of the secondary battery will be interrupted.

[0046] In this situation, the loss of the secondary battery is very large because the operation is interrupted even before the secondary battery's lifespan is exhausted.

[0047] Therefore, the electrode assembly according to this disclosure can be more appropriately applied to the 1+1 patch structure described above.

[0048] Of course, it can also be used effectively in a 1+2 contact structure that includes two negative contacts, as it can prevent a sudden increase in resistance.

[0049] Meanwhile, the sheet-like positive electrode 110 includes a positive electrode coated portion 110a and a positive electrode uncoated portion 110b. In the positive electrode coated portion 110a, a positive electrode active material layer 112 is formed on the positive electrode current collector 111. In the positive electrode uncoated portion 110b, no positive electrode active material layer 112 is formed. The positive electrode uncoated portion 110b can be a free-edge positive electrode with the following structure: in the structure, the positive electrode uncoated portion 110b is formed between the positive electrode coated portions 110a rather than at the end of the sheet-like positive electrode 110, that is, it is formed in the middle of the sheet-like positive electrode 110.

[0050] In this case, the positive electrode tab 113 can be positioned on the uncoated portion 110b of the positive electrode. In this case, the positive electrode tab 113 can be attached to the uncoated portion 110b of the positive electrode using welding, an adhesive tape, or a conductive adhesive, or can be manufactured to include the positive electrode tab 113 when manufacturing the current collector 111, and is not limited as long as the positive electrode tab 113 forms an electrical connection in a form where the positive electrode tab 113 is positioned on the uncoated portion 110b of the positive electrode.

[0051] In addition, the figure illustrates a structure in which the positive electrode tab 113 is positioned in a direction facing the sheet-like negative electrode 120, but this structure is not limited thereto.

[0052] Here, the positive electrode active material layer 112 is manufactured by applying, drying, and rolling a slurry containing the positive electrode active material onto the positive electrode current collector 111. Here, the slurry may include a conductive agent, a binder, or a filler in addition to the positive electrode active material.

[0053] The positive electrode current collector generally can have a thickness of 3 μm to 500 μm. The positive electrode current collector is not particularly limited as long as it has high conductivity without causing any chemical changes in the battery, and for example, stainless steel, aluminum, nickel, titanium, sintered carbon, or aluminum or stainless steel whose surface is treated with carbon, nickel, titanium, silver, etc. can be used. In addition, the current collector may have fine protrusions and depressions formed on its surface to enhance the adhesion of the positive electrode active material. For example, the current collector can be used in various forms such as film, sheet, foil, net, porous body, foam body, and non-woven fabric structure.

[0054] Furthermore, the positive electrode active material is a compound capable of reversibly inserting and extracting lithium, and specifically, the positive electrode active material may include a lithium metal oxide containing lithium and at least one metal such as iron, cobalt, manganese, nickel, or aluminum.

[0055] Specifically, the lithium metal oxide may include lithium-manganese-based oxides (e.g., LiMnO2, LiMn2O4, etc.), lithium-cobalt-based oxides (e.g., LiCoO2, etc.), lithium-nickel-based oxides (e.g., LiNiO2, etc.), lithium-nickel-manganese-based oxides (e.g., LiNi 1-Y Mn Y O2 (where 0 < Y < 1), LiMn 2-Z Ni z O4 (where 0 < Z < 2), etc.), lithium-nickel-cobalt-based oxides (e.g., LiNi 1-Y1 Co Y1 O2 (where 0 < Y1 < 1), etc.), lithium-manganese-cobalt-based oxides (e.g., LiCo 1- Y2 Mn Y2O2 (where 0 < Y2 < 1), LiMn 2-Z1 Co z1 O4 (where 0 < Z1 < 2), etc.), lithium-nickel-manganese-cobalt-based oxides (e.g., Li(Ni p Co q Mn r )O2 (where 0 < p < 1, 0 < q < 1, 0 < r < 1 and p + q + r = 1) or Li(Ni p1 Co q1 Mn r1 )O4 (where 0 < p1 < 2, 0 < q1 < 2, 0 < r1 < 2 and p1 + q1 + r1 = 2), etc.), lithium-nickel-cobalt-transition metal (M) oxides (e.g., Li(Ni p2 Co q2 Mn r2 M S2 )O2 (where M is selected from the group consisting of Al, Fe, V, Cr, Ti, Ta, Mg, and Mo, and p2, q2, r2, and s2 are the atomic fractions of the respective independent elements, where 0 < p2 < 1, 0 < q2 < 1, 0 < r2 < 1, 0 < s2 < 1 and p2 + q2 + r2 + s2 = 1), etc.), lithium iron phosphate (e.g., Li 1+a Fe 1-x M x (PO 4-b )X b (where M is at least one selected from Al, Mg, and Ti, X is at least one selected from F, S, and N, -0.5 ≤ a ≤ +0.5, 0 ≤ x ≤ 0.5, 0 ≤ b ≤ 0.1)), etc., and any one of them or a compound of two or more of them can be used.

[0056] Among them, the positive electrode active material includes: lithium; and a lithium metal oxide, and the lithium metal oxide includes two or more metals selected from the group consisting of nickel, manganese, cobalt, and aluminum.

[0057] Conductive materials are components used to further improve the conductivity of the positive electrode active material. Such conductive materials are not particularly limited, as long as they are conductive without causing any chemical changes in the battery. For example, conductive materials including: carbon powder, such as carbon black, acetylene black, Ketjen black, channel black, furnace black, lamp black, or thermally cracked carbon black; graphite powder, such as natural graphite, artificial graphite, or graphite with a well-formed crystal structure; conductive nanomaterials, such as carbon nanofibers or carbon nanotubes; fluorinated carbon powder; conductive powder, such as aluminum powder and nickel powder; conductive whiskers, such as zinc oxide whiskers and potassium titanate whiskers; conductive metal oxides, such as titanium oxide; or conductive materials, such as polyphenylene derivatives. Among these materials, conductive materials include conductive nanomaterials such as carbon nanotubes or carbon nanofibers, which can further reduce the resistance of lithium metal batteries and further improve output characteristics.

[0058] Typically, based on the total weight of the positive electrode active material layer, the amount of conductive material contained can be from 1% to 20% by weight, or from 1% to 15% by weight, or from 1% to 10% by weight.

[0059] The binder selectively included in the positive electrode active material layer is a component that facilitates the bonding between the positive electrode active material and the conductive material, as well as the bonding with the current collector. Examples of binders may include polyvinylidene fluoride, polyvinyl alcohol, carboxymethyl cellulose (CMC), starch, hydroxypropyl cellulose, regenerated cellulose, polyvinylpyrrolidone, polytetrafluoroethylene, polyethylene (PE), polypropylene, ethylene-propylene-diene monomer, sulfonated ethylene-propylene-diene monomer, acrylonitrile rubber, styrene-butadiene rubber, fluororubber, etc. Mixtures or copolymers of two or more materials selected from these materials may also be used.

[0060] Typically, based on the total weight of the positive electrode active material layer, the amount of binder included can be 1% to 20% by weight, or 1% to 15% by weight, or 1% to 10% by weight.

[0061] In addition, the filler used as a component to suppress expansion is not particularly limited, as long as it can suppress the expansion of the electrode without causing any chemical changes in the battery, and examples of fillers may include: olefin polymers, such as polyethylene and polypropylene; fibrous materials, such as glass fiber and carbon fiber.

[0062] Meanwhile, the sheet-like negative electrode 120 includes a negative electrode coated portion 120a and a negative electrode uncoated portion 120b. In the negative electrode coated portion 120a, a negative electrode active material layer 122 is formed on the negative electrode current collector 121. In the negative electrode uncoated portion 120b, no negative electrode active material layer 122 is formed. The negative electrode uncoated portion 120b may be formed on one side or both sides.

[0063] In this configuration, the negative electrode contact 123 can be positioned on the uncoated negative electrode portion 120b, with the contact 123 positioned at the wound end of these uncoated negative electrode portions. In this configuration, the negative electrode contact 123 can be attached to the uncoated negative electrode portion 120b using solder, adhesive tape, or conductive adhesive, or it can be manufactured to include the negative electrode contact 123 during the manufacture of the current collector 121, and is not limited thereto, as long as the negative electrode contact 123 forms an electrical connection in the form of being positioned on the uncoated negative electrode portion 120b.

[0064] Additionally, the figure illustrates a structure in which the negative electrode contact 123 is positioned in the direction facing the sheet-like positive electrode 110, but the structure is not limited to this.

[0065] Here, the negative electrode active material layer 122 is manufactured by applying, drying, and rolling a slurry containing a negative electrode active material onto the negative electrode current collector 121. In addition to the negative electrode active material, the slurry may also include conductive agents, binders, or fillers, as described for the positive electrode.

[0066] The negative electrode current collector can typically have a thickness ranging from 3 μm to 500 μm. Furthermore, the negative electrode current collector is not particularly limited, as long as it has high conductivity without causing any chemical changes in the battery. For example, the negative electrode current collector can be selected from the group consisting of: copper, stainless steel, aluminum, nickel, titanium, sintered carbon, copper with different metal surface treatments, stainless steel with different metal surface treatments, and aluminum-cadmium alloys. The current collector can have fine protrusions and depressions formed on its surface to enhance the adhesion of the negative electrode active material, and the current collector can be used in various forms such as films, sheets, foils, meshes, porous bodies, foams, and nonwoven fabric structures.

[0067] The negative electrode active material may include at least one carbon-based material selected from the group consisting of: graphite, amorphous hard carbon, low-crystallinity soft carbon, carbon black, Ketjen black, Super P (carbon black), graphene, and carbon fiber; silicon-based materials; and metal composite oxides, such as Li. x Fe2O3 (0≤x≤1), Li x WO2 (0≤x≤1), Sn x Me 1-x Me' y O z(Me: Mn, Fe, Pb, Ge; Me': Al, B, P, Si, Group 1, 2, 3 elements in the periodic table, halogens; 0 < x ≤ 1; 1 ≤ y ≤ 3; 1 ≤ z ≤ 8); lithium metal; lithium alloy; silicon-based alloy; tin-based alloy; metal oxides such as SiO, SiO2, SnO, SnO2, PbO, PbO2, Pb2O3, Pb3O4, Sb2O3, Sb2O4, Sb2O5, GeO, GeO2, Bi2O3, Bi2O4 and Bi2O5; conductive polymers such as polyacetylene; Li-Co-Ni-based materials; titanium oxide; lithium titanium oxide, etc., but not limited thereto, as long as they are known in the art.)

[0068] The sheet-like separator 130 can be made of olefin polymers such as polyethylene or polypropylene, glass fibers, etc. in the form of sheets, multilayer films, microporous membranes, woven fabrics, non-woven fabrics, etc., but not necessarily limited thereto. The sheet-like separator can be an insulating film with high ion permeability and mechanical strength, and the pore size of the separator can generally be in the range of 0.01 μm to 10 μm, and the thickness can generally be in the range of 5 μm to 300 μm, but not limited thereto.

[0069] In addition, the sheet-like separator can be combined with the electrolyte and interposed between the sheet-like positive electrode and the sheet-like negative electrode in the form of an electrolyte film or an electrolyte membrane. In this case, the electrolyte film or the electrolyte membrane can be in the form of including the above-mentioned lithium salt and non-aqueous organic solvent in a polymer matrix, and a known polymer-based solid electrolyte, etc. can be used as the polymer matrix. In this case, it can be a semi-solid battery used in combination with the liquid electrolyte injected during the manufacture of the secondary battery.

[0070] At the same time, this electrode assembly 100 has the following problem: The part of the winding end of the sheet-like negative electrode 120 facing the sheet-like positive electrode 110 is continuously impacted by the expansion of the sheet-like positive electrode 110 due to charging and discharging, and breaks, which leads to the problem of short circuit.

[0071] However, since the electrical connection of the negative electrode tab 123 stops due to this break, the operation of the secondary battery is interrupted before the life of the secondary battery is exhausted.

[0072] Therefore, in order to prevent such problems, the electrode assembly 100 according to an embodiment of the present disclosure has the following structure: In this structure, the electronically conductive band 124 is attached to the outer surface of the sheet-like negative electrode 120 that does not face the sheet-like positive electrode 110 in a portion corresponding to the winding end of the sheet-like positive electrode 且沿片状负极120的与层叠件100’的卷绕方向垂直的宽度方向(w)。

[0073] It should be noted that there seems to be an incomplete expression in the translation of . The original text "沿片状负极120的与层叠件100’的卷绕方向垂直的宽度方向(w)" is not fully translated in the provided English text. It should be something like "along the width direction (w) perpendicular to the winding direction of the laminate 100' of the sheet-like negative electrode 120". Please check and correct if necessary.In this configuration, the electronic conductive strip 124 can be attached to the outer surface of the sheet-like negative electrode 120 and has an extension width (d1, d2) of 0.5 mm to 35 mm on both sides based on the wound end edge of the sheet-like positive electrode 110.

[0074] Specifically, the width (d1, d2) of the edge on both sides can be from 1 mm to 30 mm, and more specifically from 5 mm to 20 mm.

[0075] If the width is formed too thin outside the above range, it will be difficult to achieve the effect expected by this disclosure, and if the width is formed too thick, it may affect the negative electrode active material layer, which is not preferred.

[0076] Furthermore, in order to achieve the effects anticipated by this disclosure, the electronic conductive band 124 must exhibit electronic conductivity, thereby the resistance of the electronic conductive band 124 can be 0.01 Ω / cm. 2 Up to 100 Ω / cm 2 Specifically, it is 0.1 Ω / cm 2 Up to 80 Ω / cm 2 And more specifically, 5 Ω / cm 2 Up to 30 Ω / cm 2 .

[0077] If the resistance is too high and exceeds the above range, it is impossible to obtain the effect desired by this disclosure, namely, to prevent the operation of the secondary battery from being interrupted by maintaining conductivity even when the sheet negative electrode 120 breaks, and it is difficult to manufacture a strip with a resistance lower than the above range, which is not preferred.

[0078] In addition, the electronically conductive strip 124 can be elastic, and this elasticity can delay the breakage and short circuit of the sheet-like negative electrode 120.

[0079] In this case, the electronically conductive strip 124 may have a structure in which an electronically conductive adhesive layer is formed on the substrate to provide electronic conductivity, and more specifically, the electronically conductive adhesive layer may be a single-sided strip or a double-sided strip formed on one or both surfaces of the substrate.

[0080] The substrate is not limited, as long as it is a material that can be used in secondary batteries. However, the substrate can be, for example, a polymer substrate, more specifically a polyolefin substrate, and more specifically, for example, polyethylene (PE) or polypropylene (PP).

[0081] Additionally, the adhesive layer may include an adhesive and a conductive material. Here, the adhesive may be a polymeric material with adhesive properties, and may include at least one material selected from the group consisting of polycarbonate (PC), polyacrylate (PA), rubber, and styrene.

[0082] Furthermore, the conductive material is not limited to materials that are conductive, but can be, for example, carbon materials, metals or half-metals, and specifically, it can be carbon materials.

[0083] Most specifically, the electronically conductive band can be a carbon band.

[0084] By attaching the electronically conductive strip 124, the electrode assembly 100 of this disclosure has the effect of delaying short circuits in the sheet-like negative electrode 120 corresponding to the end of the sheet-like positive electrode 110. Furthermore, even if a short circuit occurs in the sheet-like negative electrode 120, the electronically conductive strip 124 can maintain electronic conductivity, thereby enabling the secondary battery to operate continuously and thus improving the battery's lifespan.

[0085] Therefore, according to another embodiment of this disclosure, a lithium secondary battery including an electrode assembly is provided.

[0086] Here, the lithium secondary battery has a structure in which the electrode components and the lithium non-aqueous electrolyte are embedded in the battery case.

[0087] Lithium non-aqueous electrolytes can include non-aqueous organic solvents and lithium salts.

[0088] Lithium salts included in lithium non-aqueous electrolytes serve as a medium for transferring ions within a secondary battery. For example, the lithium salt may include Li+ as a cation and may together include anions selected from the group consisting of: F... - Cl - ,Br - I - NO3 - N(CN)2 - BF4 - ClO4 - B 10 Cl 10 - AlCl4 - AlO2 - PF6 - CF3SO3 - CH3CO2 - CF3CO2 - AsF6 - SbF6 - CH3SO3 - (CF3CF2SO2)2N - (CF3SO2)2N - (FSO2)2N - BF2C2O4 - BC4O8 -PF4C2O4 - PF2C4O8 - (CF3)2PF4 - (CF3)3PF3 - (CF3)4PF2 - (CF3)5PF - (CF3)6P - C4F9SO3 - CF3CF2SO3 - CF3CF2(CF3)2CO - (CF3SO2)2CH - CF3(CF2)7SO3 - and SCN - .

[0089] Specifically, the lithium salt may include at least one selected from the group consisting of: LiCl, LiBr, LiI, LiBF4, LiClO4, LiB 10 Cl 10 LiAlCl4, LiAlO2, LiPF6, LiCF3SO3, LiCH3CO2, LiCF3CO2, LiAsF6, LiSbF6, LiCH3SO3, LiFSI (lithium bis(fluorosulfonyl)imide), LiN(SO2F)2, LiBETI (lithium bis(pentafluoroethanesulfonyl)imide, LiN(SO2CF2CF3)2 and LiTFSI (lithium bis(trifluoromethanesulfonyl)imide, LiN(SO2CF3)2).

[0090] The concentration of lithium salts can be appropriately varied within the generally available range and can be included in the electrolyte at concentrations of 0.5M to 6M or 1M to 5M.

[0091] On the other hand, the types of non-aqueous organic solvents that can be included in the electrolyte are not particularly limited, and any organic solvent previously known to be suitable for lithium-ion batteries can be used. Examples of such organic solvents include at least one selected from the group consisting of: carbonate-based solvents, ether-based solvents, nitrile-based solvents, phosphate-based solvents, and sulfone-based solvents.

[0092] More specifically, carbonate-based solvents may include dimethyl carbonate, diethyl carbonate, dipropyl carbonate, ethylene carbonate, propylene carbonate, butene carbonate, fluoroethylene carbonate, methyl propyl carbonate, methyl ethyl carbonate, ethyl propyl carbonate, ethyl propyl carbonate, methyl (2,2,2-trifluoroethyl) carbonate, etc., and phosphate-based solvents may include trimethyl phosphate, triethyl phosphate, 2-(2,2,2-trifluoroethoxy)-1,3,2-dioxophosphanecyclopentane-2-oxide, etc.

[0093] Furthermore, ether-based solvents may include tetrahydrofuran derivatives, such as dibutyl ether, tetraethylene glycol dimethyl ether, diethylene glycol dimethyl ester, dimethoxyethane, or 2-methyltetrahydrofuran, and nitrile-based solvents may include succinic anhydride, adiponitrile, sebacate, acetonitrile, propionitrile, etc. Additionally, sulfone-based solvents may include dimethyl sulfone, ethylmethyl sulfone, sulfolane, etc.

[0094] Figure Labels

[0095] 100: Electrode assembly,

[0096] 110: Plate-shaped positive electrode,

[0097] 120: Plate-shaped negative electrode,

[0098] 130: Sheet-shaped separator,

[0099] 124: Electron conduction band.

[0100] Industrial applicability

[0101] The electrode assembly for a secondary battery according to this disclosure has the effect of delaying a short circuit in the sheet-like negative electrode corresponding to the end of the sheet-like positive electrode by attaching the electronic conductive strip to the outer surface of the sheet-like negative electrode corresponding to the end of the sheet-like positive electrode.

[0102] Furthermore, even if a short circuit occurs at the sheet-like negative electrode corresponding to the end of the sheet-like positive electrode, the electrode assembly for a secondary battery according to this disclosure can maintain electronic conductivity, thereby enabling the secondary battery to operate continuously and extending its lifespan.

Claims

1. An electrode assembly for a secondary battery, The electrode assembly has a structure in which a laminated component, including a sheet-like positive electrode, a sheet-like negative electrode, and a sheet-like spacer inserted between the sheet-like positive electrode and the sheet-like negative electrode, is wound up. in, The electronic conductive strip is attached to the outer surface of the sheet-like negative electrode that does not face the sheet-like positive electrode at a portion corresponding to the wound end of the sheet-like positive electrode, along the width direction of the sheet-like negative electrode perpendicular to the winding direction of the laminate.

2. The electrode assembly according to claim 1, wherein: The electron conduction band has a strength of 0.01 Ω / cm. 2 Up to 100 Ω / cm 2 The resistance.

3. The electrode assembly according to claim 1, wherein: The electronically conductive band is elastic.

4. The electrode assembly according to claim 1, wherein: The electronically conductive strip has a structure in which an electronically conductive adhesive layer is formed on a substrate.

5. The electrode assembly according to claim 4, wherein: The electronically conductive strip is a strip in which the electronically conductive adhesive layer is formed on one or both surfaces of the substrate.

6. The electrode assembly according to claim 4, wherein: The electronically conductive adhesive layer comprises a carbon material.

7. The electrode assembly according to claim 1, wherein: The electron-conducting band is a carbon band.

8. The electrode assembly according to claim 1, wherein: The electronic conductive strip is attached to the outer surface of the sheet-like negative electrode to have an extension width of 0.5 mm to 35 mm on both sides based on the edge of the wound end of the sheet-like positive electrode.

9. The electrode assembly according to claim 1, wherein: The length of the sheet-shaped negative electrode in the winding direction is longer than the length of the sheet-shaped positive electrode in the winding direction.

10. The electrode assembly according to claim 1, wherein: The electrode assembly has a structure in which the sheet-like positive electrode is wound such that the sheet-like positive electrode is positioned on the inside.

11. The electrode assembly according to claim 1, wherein: The sheet-shaped positive electrode includes a positive electrode contact, and the sheet-shaped negative electrode includes a negative electrode contact.

12. The electrode assembly according to claim 11, wherein: The sheet-like positive electrode is a free-edge positive electrode, wherein the uncoated portion of the positive electrode without a positive electrode active material layer is formed in the middle, and the positive electrode tab is positioned on the uncoated portion of the positive electrode.

13. The electrode assembly according to claim 11, wherein: The sheet-like negative electrode has the following structure: in the structure, the uncoated portion of the negative electrode without a negative electrode active material layer is formed on one or both sides, and the uncoated portion of the negative electrode is formed to include a wound end.

14. The electrode assembly of claim 13, wherein: The negative electrode contact is positioned on the uncoated portion of the negative electrode formed at the winding end.

15. A lithium secondary battery comprising an electrode assembly according to any one of claims 1 to 14.

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