Secondary battery

Abstract

The present invention relates to a secondary battery in which a thin film insulation washer is closely attached and fixed to an upper side of the electrode assembly through an insulating shrink tube, so that the secondary battery can achieve insulation between a case and an electrode assembly up to a region adjacent to a terminal. As an example, the present invention provides a secondary battery comprising: an electrode assembly including a first electrode, a separator, and a second electrode; a first current collecting plate in contact with the first electrode exposed on an upper surface of the electrode assembly; an insulating washer covering an upper surface of the first current collecting plate; an insulating shrink tube surrounding the electrode assembly, the first current collecting plate, and the insulating washer; a cylindrical case for accommodating the electrode assembly, the first current collecting plate, and the insulating washer, and having an open lower end; a terminal electrically connected to the first current collecting plate, and passing through an upper part of the case to be exposed to the outside of the case; and a cap plate for sealing the lower end part of the case.

Description

secondary battery

[0001] The present disclosure relates to a secondary battery.

[0002] Secondary batteries are power storage systems that offer superior energy density by converting electrical energy into chemical energy and storing it. Compared to non-rechargeable primary batteries, secondary batteries are rechargeable and are widely used in IT devices such as smartphones, cellphones, laptops, and tablet PCs. Recently, interest in electric vehicles has grown to prevent environmental pollution, leading to the adoption of high-capacity secondary batteries in electric vehicles. These secondary batteries require high density, high output, and stability.

[0003] The above-described information disclosed in the background technology of this invention is only intended to improve understanding of the background of the present invention, and therefore may include information that does not constitute prior art.

[0004] The present invention enables insulation between the case and the electrode assembly up to the area adjacent to the terminal by closely contacting and fixing a thin film insulating washer to the upper side of the electrode assembly through an insulating shrink tube, and facilitates insertion and alignment within the case.

[0005] However, the technical problems to be solved by the present invention are not limited to the problems described above, and other problems not mentioned can be clearly understood by those skilled in the art from the description of the invention described below.

[0006] According to one embodiment of the present invention for solving the above technical problem, a secondary battery may include an electrode assembly having a first electrode, a separator, and a second electrode, a first collector plate in contact with the first electrode exposed on an upper surface of the electrode assembly, an insulating washer covering an upper surface of the first collector plate, an insulating shrink tube wrapping the electrode assembly, the first collector plate, and the insulating washer, a cylindrical case accommodating the electrode assembly, the first collector plate, and the insulating washer and having an open lower portion, a terminal electrically connected to the first collector plate, penetrating an upper portion of the case and exposed to the outside of the case, and a cap plate sealing a lower portion of the case.

[0007] The above insulating shrink tube may include a main body portion that wraps around a side of the electrode assembly, an upper portion that is bent from the upper end of the main body portion and contacts the upper surface of the insulating washer, and a lower portion that is bent from the lower end of the main body portion and contacts the lower surface of the electrode assembly.

[0008] The upper portion may expose a central area of ​​the upper surface of the insulating washer to the outside and cover the edge so as to overlap with the insulating washer in a plane.

[0009] The upper portion may have a length of 1 mm to 3 mm from the circumference of the insulating washer toward the center.

[0010] The first collector plate may include a first region that contacts the lower surface of the terminal, and a second region located outside the first region and interposed between the insulating washer and the electrode assembly.

[0011] The first region of the first collector plate may include a central region located on the upper side of the hollow portion of the electrode assembly and welded to the terminal.

[0012] The second region of the first collector plate can be in contact with and welded to the first electrode whose lower surface is exposed to the upper surface of the electrode assembly.

[0013] The above first collector plate may have a central collector plate hole formed in the center penetrating between the upper and lower surfaces, thereby having a circular ring shape in plan view.

[0014] The center hole of the above current collector plate may have an inner diameter smaller than the hollow portion of the electrode assembly.

[0015] The above insulating washer may have a washer center hole penetrating between the upper surface and the lower surface.

[0016] The above insulating washer can have the inner surface of the center hole of the washer contact the outer surface of the terminal.

[0017] The above terminal can be contacted and welded to the first collector plate by penetrating the center hole of the washer.

[0018] The above case may include an upper portion in the shape of a flat circular plate and a body portion in the shape of a cylinder extending downward from an edge of the upper portion.

[0019] The above insulating washer may be interposed between the upper portion of the case and the first collector plate.

[0020]

[0021] The above insulating washer may include a plurality of welding slits formed centrally along the edge.

[0022] The welding bead of the above first collector plate can be positioned within the welding slit.

[0023] The above insulating shrink tube can integrate the electrode assembly, the first collector plate, and the insulating washer.

[0024] The second collector plate may further include a flat portion that is in contact with and electrically connected to the second electrode tab exposed on the lower surface of the electrode assembly, and an extension portion that extends downward from an edge of the flat portion and is in contact with and electrically connected to the case.

[0025] According to the present invention, a secondary battery can be provided in which insulation between a case and an electrode assembly is possible up to an area adjacent to a terminal by closely contacting and fixing a thin film insulating washer to the upper side of an electrode assembly through an insulating shrink tube.

[0026] However, the effects that can be obtained through the present invention are not limited to the effects described above, and other technical effects that are not mentioned can be clearly understood by those skilled in the art from the description of the invention described below.

[0027] The following drawings attached to this specification illustrate preferred embodiments of the present invention, and together with the detailed description of the invention described below, serve to further understand the technical idea of ​​the present invention, and therefore, the present invention should not be interpreted as being limited to matters described in such drawings.

[0028] Figure 1 is a perspective view illustrating a secondary battery according to the present invention.

[0029] Figure 2 is an example of a cross-sectional view of the secondary battery illustrated in Figure 1.

[0030] Figure 3 is a cross-sectional view illustrating a bonding structure in the secondary battery of Figure 2.

[0031] Figure 4 is an example of a perspective view of the joint structure illustrated in Figure 3.

[0032] Figure 5 is another example of a perspective view of the joint structure illustrated in Figure 3.

[0033] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings. Prior to this, terms or words used in this specification and claims should not be interpreted as limited to their typical or dictionary meanings, and should be interpreted with meanings and concepts that conform to the technical spirit of the present invention based on the principle that the inventor can appropriately define the concept of a term to best explain his or her own invention. Therefore, the embodiments described in this specification and the configurations illustrated in the drawings are only some of the most preferred embodiments of the present invention and do not represent all of the technical spirit of the present invention. Therefore, it should be understood that various equivalents and modified examples may exist as substitutes for them at the time of filing this application.

[0034] Additionally, when used herein, the terms "comprise", "include" and / or "comprising", "including" specify the presence of stated features, numbers, steps, operations, elements, elements and / or groups thereof, but do not preclude the presence or addition of one or more other features, numbers, operations, elements, elements and / or groups thereof.

[0035] Additionally, to facilitate understanding of the invention, the attached drawings may not be drawn to scale and some components may be exaggerated in size. Furthermore, identical components may be assigned the same reference numbers in different embodiments.

[0036] The statement that two compared objects are "identical" means "substantially identical." Therefore, "substantially identical" may include deviations considered low in the art, such as deviations of less than 5%. Furthermore, uniformity of a parameter over a given region may imply uniformity on average.

[0037] Although the terms "first" and "second" are used to describe various components, these components are not limited by these terms. These terms are used solely to distinguish one component from another, and unless otherwise specified, a "first" component may also be a "second" component.

[0038] Throughout the specification, unless otherwise specifically stated, each element may be singular or plural.

[0039] Any configuration being placed "on (or under)" or "above (or below)" a component may mean not only that any configuration is placed in contact with the upper surface (or lower surface) of said component, but also that other configurations may intervene between said component and any configuration placed on (or below) said component.

[0040] Additionally, when it is described that a component is "connected," "coupled," or "connected" to another component, it should be understood that the components may be directly connected or connected to one another, but that other components may also be "interposed" between the components, or that each component may be "connected," "coupled," or "connected" through another component. Furthermore, when it is said that a part is electrically coupled to another part, this includes not only cases where they are directly connected, but also cases where they are connected with another element in between.

[0041] When reference is made throughout the specification to "A and / or B," this means A, B, or A and B, unless otherwise stated. In other words, "and / or" includes all or any combination of the listed items. When reference is made to "C through D," this means C or more and D or less, unless otherwise stated.

[0042] The terminology used herein is for the purpose of describing embodiments of the present disclosure and is not intended to be limiting of the present disclosure.

[0043] FIG. 1 is a perspective view illustrating a secondary battery according to the present invention, and FIG. 2 is a cross-sectional view of the secondary battery illustrated in FIG. 1.

[0044] As illustrated in FIGS. 1 and 2, the secondary battery (100) may include an electrode assembly (110), a case (120) that accommodates the electrode assembly (110) and an electrolyte therein, a terminal (150) coupled to a terminal hole provided at one end of the case (120), for example, an upper end, and a cap plate (160) that seals the other end of the case (110), for example, a lower end. The secondary battery (100) may further include a first collector plate (130) that electrically connects a first electrode plate (111) of the electrode assembly (110) and a terminal (150), and a second collector plate (140) that electrically connects a second electrode plate (112) of the electrode assembly (110) and the case (120).

[0045] The electrode assembly (110) may include a separator (113), a first electrode plate (111) and a second electrode plate (112) positioned with the separator (113) between them, and may be wound in a jelly-roll shape.

[0046] The first electrode plate (111) includes a first substrate and a first active material layer positioned on the first substrate. A first electrode tab may extend outward from a first non-conductive portion of the first substrate where the first active material layer is not positioned, and the first electrode tab may be electrically connected to a terminal (150) via a first current collector plate (130).

[0047] The second electrode plate (112) includes a second substrate and a second active material layer positioned on the second substrate. A second electrode tab may extend outward from a second non-conductive portion of the second substrate where the second active material layer is not positioned, and the second electrode tab may be electrically connected to the case (120) via the second current collector plate (140). The first electrode tab and the second electrode tab may be positioned in opposite directions in the electrode assembly (110).

[0048] The first electrode plate (111) can function as an anode. In this case, the first substrate can be composed of, for example, aluminum foil, and the first active material layer can include, for example, a transition metal oxide. The second electrode plate (112) can function as an anode. In this case, the second substrate can be composed of, for example, copper foil or nickel foil, and the second active material layer can include, for example, graphite.

[0049] The separator (113) functions to prevent short circuiting between the first electrode plate (111) and the second electrode plate (112) while allowing the movement of lithium ions. The separator (113) may be composed of, for example, a polyethylene film, a polypropylene film, a polyethylene-polypropylene film, etc.

[0050] The case (120) accommodates the electrode assembly (110) and the electrolyte, and together with the terminal (150) and the cap assembly (160), forms the outer shape of the secondary battery (100). The case (120) may include a body portion (121) having a roughly cylindrical shape, and an upper portion (122) connected to one side of the body portion (121). An inwardly deformed bead portion (123) may be positioned in the body portion (121), and an inwardly bent crimping portion (124) may be positioned at an open end of the body portion (121). The upper portion (122) may be provided with a terminal hole (122a) penetrating through the center. The upper portion (122) may be coupled by having a terminal (150) inserted into the terminal hole. An insulating member (125, 127) for sealing and electrical insulation may be further interposed between the terminal hole and the terminal (150). The beading portion (123) can prevent the electrode assembly (110) from moving inside the case (120) and facilitate the settling of the cap gasket (127) and the cap plate (160). The crimping portion (124) can firmly fix the cap plate (160) by pressing the edge of the cap plate (160) through the cap gasket (127). The case (123) may be made of, for example, nickel-plated iron.

[0051] The first collector plate (130) may have one surface that contacts and is coupled to the first electrode tab of the electrode assembly (110), and the other surface that contacts and is coupled to the terminal (150). The first collector plate (130) may be welded to the first electrode tab of the electrode assembly (110) and electrically connected. The first collector plate (130) may be welded and electrically connected while the other surface is in contact with the terminal (150).

[0052] The second collector plate (140) may have a central portion (141) that contacts and is coupled to the second electrode tab of the electrode assembly (110), and an edge portion (142) that contacts and is coupled to the body portion (121) of the case (120). The second collector plate (140) may be electrically connected by welding the central portion (141) to the second electrode tab of the electrode assembly (110). The second collector plate (140) may be electrically connected by welding the edge portion (142) in a state of contacting the beading portion (123) of the case (120).

[0053] The terminal (150) may include a head (151) positioned on the outside of the case (120), and a fastening portion (152) extending inwardly from the center of the head (151) toward the inside of the case (120). The terminal (150) may be fixed and sealed by having the fastening portion (152) coupled to a terminal hole (122a) together with a terminal gasket (125) and by pressing the upper portion (122) of the case (120) from the inside through the terminal gasket (125). The terminal (150) may be electrically connected by being welded to the first collector plate (130) inside the case (120). The terminal (150) may be electrically connected to the first electrode plate (111) of the electrode assembly (110) through the first collector plate (130). The terminal (150) and the case (120) may have different polarities. The cap plate (160) may be fixed to the inside of the crimping portion (124) through the cap gasket (127) to seal the case (120). The cap plate (160) may include a safety vent (165) that is thinner than other areas due to a notch. When gas is generated due to overcharging or abnormal operation of the secondary battery (100), the safety vent (165) provided in the cap plate (160) may be cut along the notch. The cut safety vent (165) may release the gas to the outside to prevent an explosion of the secondary battery (100).

[0054] The insulating washer (170) and the insulating shrink tube (180) can electrically insulate between the case (120) and the second electrode plate (112) of the electrode assembly (110).

[0055] However, the present invention is not limited thereto, and the case may be configured in various shapes, such as circular or pouch-shaped. In addition, the case may be configured of a metal such as aluminum, aluminum alloy, nickel-plated steel, or a laminate film or plastic forming a pouch.

[0056] FIG. 3 is a cross-sectional view of a combined structure in which an electrode assembly (110), a first collector plate (130), an insulating washer (170), and an insulating shrink tube (180) are combined in the secondary battery (100) illustrated in FIGS. 1 and 2. FIG. 4 is also a perspective view of the combined structure (100A) illustrated in FIG. 3.

[0057] The electrode assembly (110) may have a first electrode tab (111a) of a first electrode plate (111) positioned at the upper portion, and a second electrode tab (112a) of a second electrode plate (112) positioned at the lower portion.

[0058] The first electrode plate (111) may be provided with a first electrode non-coated portion (111a) on the upper portion where the first electrode active material is not coated. This first electrode non-coated portion (111a) may protrude upward from the electrode assembly (110). In addition, the first electrode non-coated portion (111a) may include or be referred to as a plurality of first electrode tabs. For example, the plurality of first electrode tabs (111a) may be positioned at the upper portion of the first electrode non-coated portion, and may be arranged to be spaced apart from each other in one direction before winding. For example, the plurality of first electrode tabs (111a) may be formed on the first electrode non-coated portion by laser notching, ultrasonic cutting, or punching. The first electrode tabs (111a) may protrude further upward from the electrode assembly (110) compared to the second electrode plate (112) and the separator (113).

[0059] The second electrode plate (112) may be provided with a second electrode non-coated portion (112a) on the lower portion where the second electrode active material is not coated. In addition, the second electrode non-coated portion (112a) may include or be referred to as a plurality of second electrode tabs (112b). The plurality of second electrode tabs (112a) may be positioned on the lower portion of the second electrode non-coated portion, and may be arranged to be spaced apart from each other in one direction before winding. The plurality of second electrode tabs (112a) may be formed on the second electrode non-coated portion by laser notching, ultrasonic cutting, or punching. The plurality of second electrode tabs (112a) may protrude further downward in the electrode assembly (110) compared to the first electrode plate (111) and the separator (113).

[0060] The electrode assembly (110) may have a first electrode tab (111b) positioned on the upper surface and a second electrode tab (112a) positioned on the lower surface.

[0061] The first collector plate (130) may be a circular metal plate having a shape corresponding to the upper surface (110a) of the electrode assembly (110). The planar size of the first collector plate (130) may be equal to or smaller than the size of the upper surface (110a) of the electrode assembly (110). The first collector plate (130) may be fixed and electrically connected to the first electrode tab (111a) of the electrode assembly (110) by welding while the lower surface thereof is in contact with the upper surface (110a) of the electrode assembly (110). The first collector plate (130) may be fixed and electrically connected to the terminal (150) by welding while the upper surface thereof is in contact with the lower surface of the terminal (150). The first collector plate (130) serves as a passage for current flow between the first electrode plate (111) of the electrode assembly (110) and the terminal (150).

[0062] The first collector plate (130) may include a first region (131) that contacts the lower surface of the terminal (150), and a second region (132) that is positioned on the outside of the first region (131) on a plane and is interposed between an insulating washer (170) and an electrode assembly (110).

[0063] In addition, the first collector plate (130) may have a collector plate center hole (130a) penetrating between the upper surface and the lower surface at the center. Here, the inner diameter of the collector plate center hole (130a) may be smaller than the inner diameter of the hollow portion of the electrode assembly (110). The electrode assembly (110) may be wound, and a hollow portion penetrating between the upper surface and the lower surface may be provided in the winding core. The first region (131) of the first collector plate (130) may include a central region (131a) located above the hollow portion of the electrode assembly (110). The central region (131a) is located above the hollow portion of the electrode assembly (110), and a terminal (150) may be in contact with and welded to the upper surface. The first collector plate (130) can be joined to the terminal (150) by welding while the joining structure (100A) is inserted into the case (120). The first collector plate (130) can be welded to the terminal (150) through the hollow of the electrode assembly (110) while the upper surface of the first region (131) is in contact with the lower surface of the terminal (150). At this time, the central region (131a) of the first region (131) of the first collector plate (130) can be welded to the terminal (150).

[0064] The first collector plate (130) is welded so that the lower surface of the second region (132) is in contact with the upper surface (110a) of the electrode assembly (110), and can be in contact with and electrically connected to the first electrode tab (111a) of the electrode assembly (110).

[0065] The insulating washer (170) is a circular thin film corresponding to the shape of the first collector plate (130) and may be positioned on the upper side of the first collector plate (130). The insulating washer (170) may cover the upper surface of the second region (132) of the first collector plate (130). The insulating washer (170) may have a washer center hole (171) penetrating between the upper surface and the lower surface at the center. The insulating washer (170) may have a circular ring shape in plan view. The washer center hole (171) may have an inner diameter larger than the inner diameter of the collector plate center hole (130a) of the first collector plate (130). In addition, the washer center hole (171) may be larger than the inner diameter of the hollow portion of the electrode assembly (110). The first collector plate (130) may have the upper surface of the first region (131) exposed upward through the washer center hole (171). The upper surface of the first region (131) of the first collector plate (130) exposed through the washer center hole (171) may be in contact with the lower surface of the terminal (150). The insulating washer (170) may be in contact with the inner surface of the washer center hole (171) and the outer surface of the terminal (150). The insulating washer (170) may insulate between the case (120) and the first collector plate (130) by covering the portion of the first collector plate (130) other than the first region (131) that is in contact with the terminal (150).

[0066] The insulating washer (170) may be made of an insulating material. For example, the insulating washer (170) may have a non-woven, fiber-like, or mesh-like structure including PI (poly imide), PET (polyethylene terephthalate), PP (poly propylene), or paper. Since the insulating washer (170) is fixed to the upper side of the electrode assembly (110) together with the first collector plate (130) by an insulating shrink tube (180), even if it has a thin film thickness, it may be easy to insert into the case (120) and align with the electrode assembly (110). For example, the thickness of the insulating washer (170) may be 0.018 mm to 0.15 mm. If the thickness of the insulating washer (170) is less than 0.018 mm, it may be difficult to manufacture and difficult to maintain insulating properties, and if it exceeds 0.15 mm, it may only result in an unnecessary increase in volume. In this way, the insulating washer (170) can thin the composition of the insulating material compared to the internal space of the case (120), so that the capacity of the electrode assembly (110) can be increased compared to the same space.

[0067] In addition, the insulating washer (170) may include a plurality of welding slits (172) formed from the edge toward the center. In FIG. 4, the number of welding slits (172) of the insulating washer (170) is illustrated as four, but the number may be more or less than this and the number is not limited. The plurality of welding slits (172) may be positioned symmetrically with respect to the washer center hole (171). The welding slits (172) may be spaced apart from the washer center hole (171). The upper surface of the first collector plate (130) may be exposed through the welding slits (172).

[0068] The bonding structure (100A) can be welded between the first collector plate (130) and the first electrode tab (111a) of the electrode assembly (110) through a welding slit (172) on the upper side of the insulating washer (170). At this time, a welding bead can be created on the upper surface of the first collector plate (130), and the welding bead can be located within the welding slit (172). The second region (132) of the first collector plate (130) can be in contact with and welded to the first electrode tab (111a) of the electrode assembly (110).

[0069] As another example, the first collector plate (130) may be welded to the upper portion of the electrode assembly (110) and may be combined with an insulating washer (170) and an insulating shrink tube (180) to form a joining structure (100A). At this time, the insulating washer (170) may not have a separate welding slit (172), and a perspective view of the joining structure (100B) may be as in FIG. 5. Here, the joining structure (100B) may have a structure and a joining relationship similar to the joining structure (100A) illustrated in FIGS. 3 and 4, and the insulating washer (170) may not include a welding slit (172).

[0070] The insulating shrink tube (180) may be made of a shrinkable material. For example, the insulating shrink tube (180) may be made of an insulating material that shrinks with heat. After the insulating shrink tube (180) wraps around a structure in which the first collector plate (130) and the insulating washer (170) are mounted on the upper side of the electrode assembly (110), the insulating shrink tube (180) shrinks to tightly adhere and fix the first collector plate (130) and the insulating washer (170) on the electrode assembly (110). For example, the insulating shrink tube (180) may include one or more of PVDF (Polyvinylidene Fluoride), PTFE (Polytetrafluoroethylene), FEP (Fluoro Ethylene Propylene), and fluoroelastomer. The insulating shrink tube (180) can secure the first collector plate (130) and the insulating washer (170) on the electrode assembly (110) without a separate adhesive component.

[0071] The insulating shrink tube (180) may include a main body portion (181) that wraps around the side of the electrode assembly (110), an upper portion (182) that is bent from the upper end of the main body portion (181) and contacts the upper surface of the insulating washer (170), and a lower portion (183) that is bent from the lower end of the main body portion (181) and contacts the lower surface of the electrode assembly (110).

[0072] The upper end (182) of the insulating shrink tube (180) may overlap with the insulating washer (170) on a flat surface. The insulating shrink tube (180) may cover the upper side of the edge area of ​​the insulating washer (170). The central area of ​​the upper surface of the insulating washer (170) of the insulating shrink tube (180) may be exposed to the outside. The length of the upper end where the upper end (182) of the insulating shrink tube (180) overlaps with the insulating washer (170) may be 1 mm to 3 mm. Here, the length of the upper end may be the length from the circumference of the insulating washer (170) toward the center. When the length of the upper end (182) is less than 1 mm, the insulating washer (170) may be separated from the insulating shrink tube (180), and when it exceeds 3 mm, it may be difficult to adhere to the insulating washer (170) due to the limitation of the shrinkage length. In this way, the insulating shrink tube (180) cannot insulate between the upper side of the electrode assembly (110) and the first collector plate (130) and the case (120) due to the limitation of the shrinkable length. The insulating washer (170) can insulate between the second region (132) of the first collector plate (130) that is not protected by the insulating shrink tube (180) and the case (120).

[0073] Additionally, a compound capable of reversible intercalation and deintercalation of lithium (a lithiated intercalation compound) may be used as the positive electrode active material. Specifically, one or more of a composite oxide of lithium and a metal selected from cobalt, manganese, nickel, and combinations thereof may be used.

[0074] The above composite oxide may be a lithium transition metal composite oxide, and specific examples thereof include lithium nickel-based oxide, lithium cobalt-based oxide, lithium manganese-based oxide, lithium iron phosphate-based compound, cobalt-free nickel-manganese-based oxide, or a combination thereof.

[0075] As an example, a compound represented by any one of the following chemical formulas may be used. LiaA1-bXbO2-cDc(0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.05); LiaMn2-bXbO4-cDc(0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.05); LiaNi1-b-cCobXcO2-αDα(0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.5, 0<α<2); LiaNi1-b-cMnbXcO2-αDα(0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.5, 0<α<2); LiaNibCocL1dGeO2(0.90≤a≤1.8, 0≤b≤0.9, 0≤c≤0.5, 0≤d≤0.5, 0≤e≤0.1); LiaNiGbO2(0.90≤a≤1.8, 0.001≤b≤0.1); LiaCoGbO2(0.90≤a≤1.8, 0.001≤b≤0.1); LiaMn1-bGbO2 (0.90≤a≤1.8, 0.001≤b≤0.1); LiaMn2GbO4 (0.90≤a≤1.8, 0.001≤b≤0.1); LiaMn1-gGgPO4(0.90≤a≤1.8, 0≤g≤0.5); Li(3-f)Fe2(PO4)3(0≤f≤2); LiaFePO4(0.90≤a≤1.8).

[0076] In the chemical formula, A is Ni, Co, Mn, or a combination thereof; X is Al, Ni, Co, Mn, Cr, Fe, Mg, Sr, V, a rare earth element, or a combination thereof; D is O, F, S, P, or a combination thereof; G is Al, Cr, Mn, Fe, Mg, La, Ce, Sr, V, or a combination thereof; and L1 is Mn, Al, or a combination thereof.

[0077] A positive electrode for a lithium secondary battery may include a current collector and a positive electrode active material layer formed on the current collector. The positive electrode active material layer includes a positive electrode active material and may further include a binder and / or a conductive material.

[0078] The content of the positive electrode active material may be 90 wt% to 99.5 wt% with respect to 100 wt% of the positive electrode active material layer, and the contents of the binder and conductive material may be 0.5 wt% to 5 wt%, respectively, with respect to 100 wt% of the positive electrode active material layer.

[0079] Al may be used as the above current collector, but is not limited thereto.

[0080] The negative electrode active material includes a material capable of reversibly intercalating / deintercalating lithium ions, lithium metal, an alloy of lithium metal, a material capable of doping and dedoping lithium, or a transition metal oxide.

[0081] The material capable of reversibly intercalating / deintercalating the lithium ions may include a carbon-based negative electrode active material, for example, crystalline carbon, amorphous carbon, or a combination thereof. Examples of the crystalline carbon include graphite such as natural graphite or artificial graphite, and examples of the amorphous carbon include soft carbon or hard carbon, mesophase pitch carbide, calcined coke, and the like.

[0082] As the material capable of doping and dedoping the lithium, a Si-based negative electrode active material or a Sn-based negative electrode active material can be used. The Si-based negative electrode active material can be silicon, a silicon-carbon composite, SiOx (0 < x < 2), a Si-based alloy, or a combination thereof.

[0083] The above silicon-carbon composite may be a composite of silicon and amorphous carbon. According to one embodiment, the silicon-carbon composite may be in the form of silicon particles and amorphous carbon coated on the surface of the silicon particles.

[0084] The silicon-carbon composite may further comprise crystalline carbon. For example, the silicon-carbon composite may comprise a core comprising crystalline carbon and silicon particles and an amorphous carbon coating layer positioned on the surface of the core.

[0085] A negative electrode for a lithium secondary battery includes a current collector and a negative electrode active material layer positioned on the current collector. The negative electrode active material layer includes a negative electrode active material and may further include a binder and / or a conductive material.

[0086] For example, the negative electrode active material layer may include 90 to 99 wt% of the negative electrode active material, 0.5 to 5 wt% of the binder, and 0 to 5 wt% of the conductive material.

[0087] The above binder may be a non-aqueous binder, an aqueous binder, a dry binder, or a combination thereof. When an aqueous binder is used as the negative electrode binder, a cellulose-based compound capable of imparting viscosity may be further included.

[0088] The negative electrode current collector may be selected from copper foil, nickel foil, stainless steel foil, titanium foil, nickel foam, copper foam, a polymer substrate coated with a conductive metal, and a combination thereof.

[0089] An electrolyte for a lithium secondary battery contains a non-aqueous organic solvent and a lithium salt.

[0090] The above non-aqueous organic solvent acts as a medium through which ions involved in the electrochemical reaction of the battery can move.

[0091] The above non-aqueous organic solvent may be a carbonate-based, ester-based, ether-based, ketone-based, or alcohol-based solvent, an aprotic solvent, or a combination thereof, and may be used alone or in combination of two or more thereof.

[0092] Additionally, when using a carbonate solvent, a mixture of cyclic carbonate and chain carbonate can be used.

[0093] Depending on the type of lithium secondary battery, a separator may be present between the positive and negative electrodes. Such separators may be polyethylene, polypropylene, polyvinylidene fluoride, or a multilayer film comprising two or more layers of these.

[0094] The above separator may include a porous substrate and a coating layer comprising an organic material, an inorganic material, or a combination thereof, positioned on one or both sides of the porous substrate.

[0095] The above organic material may include a polyvinylidene fluoride-based antibody or a (meth)acrylic polymer.

[0096] The above inorganic material may include inorganic particles selected from, but not limited to, Al2O3, SiO2, TiO2, SnO2, CeO2, MgO, NiO, CaO, GaO, ZnO, ZrO2, Y2O3, SrTiO3, BaTiO3, Mg(OH)2, boehmite, and combinations thereof.

[0097] The organic and inorganic substances may be mixed and present in one coating layer, or a coating layer including an organic substance and a coating layer including an inorganic substance may be present in a laminated form.

[0098] Although the present invention has been described above with reference to limited embodiments and drawings, the present invention is not limited thereto, and it is obvious that various modifications and variations are possible within the scope of the technical idea of ​​the present invention and the equivalent scope of the patent claims to be described below by a person having ordinary skill in the art to which the present invention pertains.

Claims

1. An electrode assembly having a first electrode, a separator, and a second electrode; A first collector plate in contact with a first electrode exposed on the upper surface of the electrode assembly; An insulating washer covering the upper surface of the first collector plate; An insulating shrink tube surrounding the electrode assembly, the first collector plate, and the insulating washer; A cylindrical case in which the electrode assembly, the first collector plate, and the insulating washer are accommodated, and the lower end is open; A terminal electrically connected to the first collector plate, penetrating the upper part of the case and exposed to the outside of the case; and A secondary battery including a cap plate sealing the lower part of the case.

2. In paragraph 1, The above insulating shrink tube is A main body portion that surrounds the side of the electrode assembly; An upper portion bent from the upper portion of the main body and in contact with the upper surface of the insulating washer; and A secondary battery including a lower portion that is bent from the lower portion of the main body and contacts the lower surface of the electrode assembly.

3. In paragraph 2, The upper portion is a secondary battery that exposes the central area to the outside from the upper surface of the insulating washer and covers the edge to overlap the insulating washer in a plane.

4. In paragraph 2, A secondary battery in which the upper portion has a length of 1 mm to 3 mm from the circumference of the insulating washer toward the center.

5. In paragraph 1, The above first collector plate A first region that comes into contact with the lower surface of the terminal; and A secondary battery comprising a second region located outside the first region and interposed between the insulating washer and the electrode assembly.

6. In paragraph 5, A secondary battery in which the first region of the first collector plate is located on the upper side of the hollow portion of the electrode assembly and includes a central region welded to the terminal.

7. In paragraph 5, A secondary battery in which the second region of the first collector plate is in contact with and welded to the first electrode whose lower surface is exposed to the upper surface of the electrode assembly.

8. In paragraph 1, The above first collector plate is a secondary battery having a central collector plate hole formed in the center penetrating between the upper and lower surfaces, and having a circular ring shape on a plane.

9. In paragraph 8, A secondary battery in which the center hole of the above-mentioned current collector plate has an inner diameter smaller than the hollow portion of the above-mentioned electrode assembly.

10. In paragraph 1, The above insulating washer is a secondary battery having a washer center hole penetrating between the upper and lower surfaces.

11. In paragraph 10, The above insulating washer is a secondary battery in which the inner surface of the center hole of the washer is in contact with the outer surface of the terminal.

12. In paragraph 10, A secondary battery in which the terminal penetrates the center hole of the washer and contacts and is welded to the first collector plate.

13. In paragraph 1, The above case is The upper part is in the shape of a flat circular plate; and A secondary battery comprising a cylindrical body extending downward from the upper edge.

14. In paragraph 13, The above insulating washer is a secondary battery interposed between the upper part of the case and the first collector plate.

15. In paragraph 1, The above insulating washer is a secondary battery including a plurality of welding slits formed in a central direction at the edge.

16. In paragraph 15, A secondary battery in which the welding bead of the above first collector plate is located within the welding slit.

17. In paragraph 1, A secondary battery in which the insulating shrink tube integrates the electrode assembly, the first collector plate, and the insulating washer.

18. In paragraph 1, A flat portion that is in contact with and electrically connected to the second electrode tab exposed to the lower surface of the electrode assembly; and A secondary battery further comprising a second collector plate formed of an extension portion extending downward from an edge of the flat portion and contacting and electrically connected to the case.

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