Secondary battery
Patent Information
- Application Number
- KR1020250024828
- Authority / Receiving Office
- KR · KR
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2025-02-26
- Publication Date
- 2026-09-02
Smart Images
Figure PAT00005_ABST
Abstract
Description
Technology Field
[0001] The embodiments of the present disclosure relate to secondary batteries. Background Technology
[0002] Unlike primary batteries, which cannot be recharged, secondary batteries are batteries capable of both charging and discharging. Low-capacity secondary batteries are used in small portable electronic devices such as smartphones, feature phones, laptop computers, digital cameras, and camcorders, while high-capacity secondary batteries are widely used as power sources for motor drive systems and energy storage batteries in hybrid and electric vehicles. Such secondary batteries include an electrode assembly consisting of a positive electrode and a negative electrode, a case housing the assembly, and electrode terminals connected to the electrode assembly.
[0003] The information described above disclosed in the background technology of this invention is intended only to enhance understanding of the background of the present invention and may therefore include information that does not constitute prior art. The problem to be solved
[0004] The present invention provides a secondary battery that suppresses crack formation caused by an electrode tab by adding a reinforcing member within a certain range of the electrode tab.
[0005] However, the technical problems that the present invention aims to solve are not limited to those described above, and other unmentioned problems can be clearly understood by those skilled in the art from the description of the invention below. means of solving the problem
[0006] A secondary battery according to an embodiment of the present invention for solving the above technical problem comprises: a case; an electrode assembly that is housed in the case and includes a first electrode plate, a separator located on the first electrode plate, and a second electrode plate located on the separator, wherein the first electrode plate, the separator, and the second electrode plate are stacked and wound; a cap assembly that seals the case; an insulating member attached to the first electrode plate to cover at least a portion of a first electrode tab attached to the first electrode plate; and at least one reinforcing member provided in a certain range along the same line from the winding center of the electrode assembly to the outermost edge with respect to the first electrode tab.
[0007] In some examples, the first electrode tab may be located between the winding center and the outermost edge of the electrode assembly.
[0008] In some examples, the reinforcing member may be positioned at a distance of one or two turns in the direction of the winding center of the electrode assembly relative to the first electrode tab.
[0009] In some examples, the reinforcing member may be positioned at a distance equivalent to one or two turns in the winding end direction of the electrode assembly relative to the first electrode tab.
[0010] In some examples, the width of the reinforcing member in the longitudinal direction of the first electrode plate may be equal to or greater than the width of the first electrode tab.
[0011] In some examples, the width of the reinforcing member in the longitudinal direction of the first electrode plate may be equal to or greater than the width of the insulating member.
[0012] In some examples, the reinforcing member protrudes upward or downward in the width direction of the first electrode plate, and the length of the reinforcing member protruding upward or downward in the width direction of the first electrode plate may be the same or different from each other.
[0013] In some examples, the material of the reinforcing member may be at least one of polystyrene-based (PS, polystyrene), polyester-based (PET, polyester), polyimide-based (PI, polyimide), and polyaramid-based.
[0014] In some examples, the first electrode plate comprises a first substrate having an inner surface and an outer surface, a first coating portion in which a first active material is coated on the inner surface and the outer surface of the first substrate, respectively, and a first non-coated portion in which the first active material is not coated on the inner surface and the outer surface of the first substrate, respectively, and the first non-coated portion may be located between the first coating portions.
[0015] In some examples, the first electrode tab may be provided on the inner or outer surface of the first uncoated portion, and the reinforcing member may be provided on the inner and outer surfaces of the first coating portion.
[0016] In some examples, the first electrode tab may be coupled to the inner or outer surface of the first non-reinforced portion and may further include a second non-reinforced portion provided in a certain range along the same line from the winding center of the wound electrode assembly to the outermost edge with respect to the first electrode tab.
[0017] In some examples, the reinforcing member may be provided on the inner and outer surfaces of the second non-reinforcing portion.
[0018] In some examples, the width of the reinforcing member in the longitudinal direction of the first electrode plate may be equal to or greater than the width of the second unsupported portion.
[0019] In some examples, the thickness of the reinforcing member may be the same as the thickness of the first active material of the first coating part.
[0020] In some examples, when two to four reinforcing members are provided on the same line with respect to the first electrode tab, the reinforcing members may be positioned spaced apart by a distance of one or two turns in the winding center direction of the electrode assembly with respect to the first electrode tab, and may be positioned spaced apart by a distance of one or two turns in the winding end direction of the electrode assembly with respect to the first electrode tab.
[0021] In some examples, the widths of the plurality of reinforcing members in the longitudinal direction of the first electrode plate may be the same or different from each other.
[0022] In some examples, the upper or lower protrusion lengths of the plurality of reinforcing members in the width direction of the first electrode plate may be the same or different from each other.
[0023] In some examples, the reinforcing member may include a plurality of reinforcing member units arranged with spacing.
[0024] In some examples, the thicknesses of the plurality of reinforcing member units may be the same or different from each other.
[0025] In some examples, it may further include an insulating member attached to the second electrode plate to cover at least a portion of the second electrode tab attached to the second electrode plate; and at least one reinforcing member provided in a certain range along the same line from the winding center of the wound electrode assembly to the outermost edge with respect to the second electrode tab. Effects of the invention
[0026] According to the present invention, by adding a reinforcing member within a certain range of the electrode tab so that the location of the reinforcing member becomes an unreacted part and the expansion of the electrode plate in the electrode tab portion is minimized, it is possible to prevent cracks that occur when the substrate portion in contact with the electrode tab becomes vulnerable due to the step difference of the electrode tab.
[0027] However, the effects obtainable through the present invention are not limited to those described above, and other unmentioned technical effects will be clearly understood by those skilled in the art from the description of the invention below. Brief explanation of the drawing
[0028] The following drawings attached to this specification illustrate preferred embodiments of the present invention and serve to further enhance understanding of the technical concept of the present invention together with the detailed description of the invention provided below; therefore, the present invention should not be interpreted as being limited only to the matters described in such drawings. FIG. 1 is a perspective view illustrating a secondary battery according to one embodiment of the present invention. FIG. 2 is a cross-sectional view illustrating a secondary battery according to one embodiment of the present invention. FIG. 3 is an exploded perspective view illustrating a secondary battery according to one embodiment of the present invention. FIG. 4 is a cross-sectional view illustrating an electrode assembly among secondary batteries according to one embodiment of the present invention. FIG. 5 is a front view illustrating the state before winding one reinforcing member of a secondary battery according to one embodiment of the present invention onto an electrode assembly located at the leading edge turn. FIG. 6 is a front view illustrating the state before winding a reinforcing member formed of a plurality of units in a secondary battery according to one embodiment of the present invention onto an electrode assembly located at the leading edge turn. FIG. 7 is a front view illustrating the state before winding of an electrode assembly in which two reinforcing members are positioned in one turn of a secondary battery according to one embodiment of the present invention. FIG. 8 is a front view illustrating the state before winding three reinforcing members of a secondary battery according to one embodiment of the present invention to an electrode assembly located at turn 1 and turn 2. FIG. 9 is a front view illustrating the state before winding of an electrode assembly in which four reinforcing members are located at turn 1 and turn 2 of a secondary battery according to one embodiment of the present invention. FIG. 10 is a cross-sectional view illustrating the state before winding of the first electrode plate of an electrode assembly with a reinforcing member attached, according to one embodiment of the present invention. FIG. 11 is a cross-sectional view illustrating the state before winding of the first electrode plate of an electrode assembly coated with a reinforcing member in a secondary battery according to one embodiment of the present invention. FIG. 12 is a schematic diagram simply illustrating a smartphone equipped with a secondary battery according to one embodiment of the present invention. FIGS. 13a and FIGS. 13b are perspective views illustrating an exemplary battery pack. FIGS. 14a and FIGS. 14b are a perspective view and a side view illustrating an exemplary vehicle body and vehicle body parts. Specific details for implementing the invention
[0029] Preferred embodiments of the present invention will be described in detail below with reference to the attached drawings. Prior to this, terms and words used in this specification and claims should not be interpreted as being limited to their ordinary or dictionary meanings. Instead, based on the principle that the inventor may appropriately define the concepts of terms to best describe his invention, they should be interpreted in a meaning and concept consistent with the technical spirit of the present invention. Therefore, it should be understood that the embodiments described in this specification and the configurations illustrated in the drawings are merely some of the most preferred embodiments of the present invention and do not represent all of the technical spirit of the present invention; thus, various equivalents and modifications that can replace them may exist at the time of filing this application. Furthermore, as used in this specification, "comprise" or "include" and / or "comprising" or "including" specify the presence of the mentioned features, numbers, steps, actions, parts, elements, and / or groups thereof, and do not exclude the presence or addition of one or more other features, numbers, actions, parts, elements, and / or groups. Additionally, when describing embodiments of the present invention, “may” or “may” may include “one or more embodiments of the present invention.”
[0030] Additionally, to aid in understanding the invention, the attached drawings are not drawn to actual scale, and the dimensions of some components may be exaggerated. Furthermore, the same reference numerals may be assigned to identical components in different embodiments.
[0031] The statement that two subjects of comparison are 'identical' means that they are 'substantially identical.' Therefore, substantial identity may include deviations considered low in the industry, for example, deviations within 5%. Additionally, the statement that a parameter is uniform in a given area may mean that it is uniform from an average perspective.
[0032] Although terms such as "first," "second," etc., are used to describe various components, it goes without saying that these components are not limited by these terms. These terms are used merely to distinguish one component from another, and unless specifically stated otherwise, the first component may also be the second component.
[0033] Throughout the specification, unless specifically stated otherwise, each component may be singular or plural.
[0034] The fact that any configuration is placed on the “upper (or lower)” of a component or on the “upper (or lower)” of a component may mean not only that the any configuration is placed in contact with the upper (or lower) surface of said component, but also that another configuration may be interposed between said component and any configuration placed on (or below) said component.
[0035] Furthermore, where it is stated that one component is “connected,” “coupled,” or “joined” to another component, it should be understood that while said components may be directly connected or joined to one another, another component may be “interposed” between each component, or that each component may be “connected,” “coupled,” or “joined” through another component. Additionally, when it is stated 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 an intermediate element in between.
[0036] Throughout the specification, “A and / or B” means A, B, or A and B unless specifically stated otherwise. That is, “and / or” includes any combination or any combination of the enumerated items. “C to D” means C or more and D or less, unless specifically stated otherwise.
[0037] FIG. 1 is a perspective view illustrating a secondary battery according to one embodiment of the present invention. FIG. 2 is a cross-sectional view illustrating a secondary battery according to one embodiment of the present invention. FIG. 3 is an exploded perspective view illustrating a secondary battery according to one embodiment of the present invention.
[0038] Referring to FIGS. 1 to 3, a cylindrical lithium-ion secondary battery (100) according to various embodiments of the present invention may include a cylindrical can (110), an electrode assembly (120), and a cap assembly (140). Additionally, the cylindrical lithium-ion secondary battery (100) may additionally include a center pin (130) depending on the case. Furthermore, in the secondary battery (100) according to an embodiment of the present invention, since the cap assembly (140) also performs a current interruption operation, it may be referred to as a Current Interrupt Device depending on the case.
[0039] The cylindrical can (110) may include a roughly circular bottom portion (111) and a cylindrical side wall (112) extending a certain length upward from the circumference of the bottom portion (111). During the manufacturing process of the secondary battery, the top of the cylindrical can (110) is open. Accordingly, during the assembly process of the secondary battery, the electrode assembly (120) and the center pin (130) can be inserted into the cylindrical can (110) together with the electrolyte. The cylindrical can (110) may be manufactured from, for example, but not limited to, steel, stainless steel, aluminum, aluminum alloy, or an equivalent thereof.
[0040] Additionally, the cylindrical can (110) may include a beading part (113) that is indented inwardly at the bottom of the cap assembly (140) and a crimping part (114) that is bent inwardly at the top, so that the cap assembly (140) does not detach outwardly.
[0041] The electrode assembly (120) can be housed inside a cylindrical can (110). The electrode assembly (120) may include a first electrode plate (121) in which a first active material (e.g., graphite, carbon, etc.) is coated on a first substrate, a second electrode plate (122) in which a second active material (e.g., a transition metal oxide (LiCoO2, LiNiO2, LiMn2O4, etc.)) is coated on a second substrate, and a separator (123) positioned between the first electrode plate (121) and the second electrode plate (122) to prevent short circuits and allow only the movement of lithium ions. Additionally, the first electrode plate (121), the second electrode plate (122), and the separator (123) may be wound in a roughly cylindrical shape. Here, for example, but not limited to, the first electrode plate (121) may be made of copper (Cu) foil, the second electrode plate (122) may be made of aluminum (Al) foil, and the separator (123) may be made of polyethylene (PE) or polypropylene (PP).
[0042] Additionally, a first electrode tab (124) extending downward by a certain length may be welded to the first electrode plate (121), and a second electrode tab (125) extending upward by a certain length may be welded to the second electrode plate (122), but the opposite is also possible. Furthermore, for example, but not limited to, the first electrode tab (124) may be formed of copper (Cu) or nickel (Ni), and the second electrode tab (125) may be formed of aluminum (Al).
[0043] Additionally, the first electrode tab (124) of the electrode assembly (120) can be welded to the bottom portion (111) of the cylindrical can (110). Thus, the cylindrical can (110) can operate as a negative electrode. Of course, conversely, the second electrode tab (125) can be welded to the bottom portion (111) of the cylindrical can (110), and in this case, the cylindrical can (110) can operate as a positive electrode.
[0044] In addition, a first insulating plate (126) may be interposed between the electrode assembly (120) and the bottom portion (111), with the first hole (126a) formed in the center and the second hole (126b) formed on the outer side thereof, which is coupled to the cylindrical can (110). This first insulating plate (126) serves to prevent the electrode assembly (120) from making electrical contact with the bottom portion (111) of the cylindrical can (110). In particular, the first insulating plate (126) serves to prevent the second electrode plate (122) of the electrode assembly (120) from making electrical contact with the bottom portion (111). Here, the first hole (126a) serves to allow the gas to move quickly upward through the center pin (130) when a large amount of gas is generated due to a malfunction of the secondary battery, and the second hole (126b) serves to allow the first electrode tab (124) to pass through and be welded to the bottom part (111).
[0045] Additionally, a second insulating plate (127) may be interposed between the electrode assembly (120) and the cap assembly (140), which is coupled to the cylindrical can (110) and has a first hole (127a) formed in the center and a plurality of second holes (127b) formed on the outer side thereof. This second insulating plate (127) serves to prevent the electrode assembly (120) from making electrical contact with the cap assembly (140). In particular, the second insulating plate (127) serves to prevent the first electrode plate (121) of the electrode assembly (120) from making electrical contact with the cap assembly (140). Here, the first hole (127a) serves to allow the gas to move quickly to the cap assembly (140) when a large amount of gas is generated due to a malfunction of the secondary battery, and the second hole (127b) serves to allow the second electrode tab (125) to pass through and be welded to the cap assembly (140). Additionally, the remaining second hole (127b) serves to allow the electrolyte to flow quickly into the electrode assembly (120) during the electrolyte injection process.
[0046] In addition, the diameter of the first hole (126a, 127a) of the first and second insulating plates (126, 127) is formed to be smaller than the diameter of the center pin (130), thereby preventing the center pin (130) from electrically contacting the bottom part (111) of the cylindrical can (110) or the cap assembly (140) due to external impact.
[0047] The center pin (130) is in the form of a hollow circular pipe and can be attached to the approximate center of the electrode assembly (120). This center pin (130) may be manufactured from, for example, but not limited to, steel, stainless steel, aluminum, aluminum alloy, or polybutylene terepthalate. This center pin (130) serves to suppress deformation of the electrode assembly (120) during charging and discharging of the battery and acts as a passage for gas generated inside the secondary battery. Of course, in some cases, this center pin (130) may be omitted.
[0048] The cap assembly (140) may include a cap-up (141) having a plurality of through holes (141a), a safety vent (142) located below the cap-up (141), a connecting ring (143) located below the safety vent (142), and a cap-down (144) located below the safety vent (142) and the connecting ring (143), having a plurality of through holes (144a), and electrically connected to a second electrode tab (125). In some examples, the cap assembly (140) may further include an insulating gasket (145) that insulates the cap-up (141), the safety vent (143), and the cap-down (144) from the side (111) of the cylindrical can (110).
[0049] In some examples, the insulating gasket (145) may be substantially compressed between the beading portion (113) and the crimping portion (114) formed on the side (111) of the cylindrical can (110). In some examples, the through hole (141a) of the cap-up (141) and the through hole (144a) of the cap-down (144) may discharge internal gas to the outside when abnormal internal pressure occurs inside the cylindrical can (110). In some examples, internal gas may invert the safety vent (143) upward through the through hole (144a) of the cap-down (144), electrically disconnecting the safety vent (143) from the cap-down (144), and then the safety vent (144) may be torn, allowing the internal gas to be discharged to the outside through the through hole (141a) of the cap-up (141).
[0050] In some examples, an electrolyte (not shown in the drawing) may be injected into the inside of a cylindrical can (110), which allows lithium ions generated by electrochemical reactions in the first electrode plate (121) and the second electrode plate (122) inside the battery to move during charging and discharging. This electrolyte may include a non-aqueous organic electrolyte which is a mixture of a lithium salt and a high-purity organic solvent. In some examples, the electrolyte may include a polymer or solid electrolyte using a polymer electrolyte.
[0051] The electrode assembly (120) includes a negative electrode plate, which is a first electrode plate (121), a positive electrode plate, which is a second electrode plate (122), and a separator (123) interposed between them. In some examples, the electrode assembly (120) may be formed by winding a laminate of the first electrode plate (121), which is formed as a thin plate or film, the separator (123), and the second electrode plate (122). In some examples, the electrode assembly (120) may be housed inside a case with one or more electrode assemblies (120) stacked adjacent to each other, and the present invention does not limit the number of electrode assemblies (120). The first electrode plate (121) of the electrode assembly (120) may act as a negative electrode, and the second electrode plate (122) may act as a positive electrode. Of course, the opposite is also possible.
[0052] The first electrode plate (121) may be formed by applying a first electrode active material, such as graphite or carbon, to a first electrode current collector (or first electrode current collector) formed from a metal foil such as copper, a copper alloy, nickel, or a nickel alloy. The first electrode plate (121) may include a first active material layer on which the first electrode active material is applied. The first electrode plate (121) may include a first uncoated portion, which is an area on which the first electrode active material is not applied.
[0053] The first electrode plate (121) may include a first electrode tab (124) electrically connected to the first non-reinforced portion. In some examples, the first electrode tab (124) may be fixed (e.g., welded) to the first non-reinforced portion in a roughly flat shape. For example, the first electrode tab (124) may be fixed to the first non-reinforced portion by ultrasonic welding, laser welding, or resistance welding. That is, one end of the first electrode tab (124) is electrically connected to the first non-reinforced portion, and the other end may protrude and extend outward. In some examples, the first electrode tab (124) may be formed by cutting it to protrude to one side when manufacturing the first electrode plate (121), and may protrude further to one side than the separator (123) without separate cutting.
[0054] The first active material, the negative electrode active material, comprises 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.
[0055] A material capable of reversibly intercalating / deintercalating the above lithium ions may be a carbon-based negative electrode active material, such as 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, etc.
[0056] As a material capable of doping and undoping the above lithium, a Si-based negative electrode active material or a Sn-based negative electrode active material may be used. The above Si-based negative electrode active material is silicon, a silicon-carbon composite, or SiO₂. x (0 < x < 2), may be a Si-based alloy or a combination thereof.
[0057] The 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.
[0058] The silicon-carbon composite may further include crystalline carbon. For example, the silicon-carbon composite may include a core comprising crystalline carbon and silicon particles and an amorphous carbon coating layer located on the surface of the core.
[0059] A negative electrode for a lithium secondary battery comprises a current collector and a negative electrode active material layer located on the current collector. The negative electrode active material layer comprises a negative electrode active material and may further comprise a binder and / or a conductive material.
[0060] For example, the negative electrode active material layer may comprise 90% to 99% by weight of negative electrode active material, 0.5% to 5% by weight of binder, and 0% to 5% by weight of conductive material.
[0061] As the binder, a non-aqueous binder, an aqueous binder, a dry binder, or a combination thereof may be used. When an aqueous binder is used as the cathode binder, a cellulose-based compound capable of imparting viscosity may be further included.
[0062] As the above-mentioned cathode current collector, a material selected from copper foil, nickel foil, stainless steel foil, titanium foil, nickel foam, copper foam, a polymer substrate coated with a conductive metal, and combinations thereof may be used.
[0063] The electrolyte for lithium secondary batteries contains a non-aqueous organic solvent and a lithium salt.
[0064] The above-mentioned non-aqueous organic solvent serves as a medium through which ions involved in the electrochemical reaction of the battery can move.
[0065] The above-mentioned non-aqueous organic solvent may be a carbonate-based, ester-based, ether-based, ketone-based, or alcohol-based solvent, a non-protic solvent, or a combination thereof, and may be used alone or in a mixture of two or more types.
[0066] In addition, when using carbonate-based solvents, cyclic carbonates and chain carbonates can be mixed and used.
[0067] The second electrode plate (122) may be formed by applying a second electrode active material, such as graphite or carbon, to a second electrode current collector (or second electrode current collector) formed of a metal foil such as aluminum or an aluminum alloy. The second electrode plate (122) may include a second active material layer coated with the second electrode active material. The second electrode plate (122) may include a second uncoated portion, which is an area where the second electrode active material is not coated.
[0068] The second electrode plate (122) may include a second electrode tab (125) electrically connected to the positive electrode portion. In some examples, the second electrode tab (125) may be fixed (e.g., welded) to the second electrode portion in a roughly flat shape. For example, the second electrode tab (125) may be fixed to the second electrode portion by ultrasonic welding, laser welding, or resistance welding. That is, one end of the second electrode tab (125) is electrically connected to the second electrode portion, and the other end may protrude and extend outward. In some examples, the second electrode tab (125) may be formed by cutting it to protrude to one side when manufacturing the second electrode plate (122), and may protrude further to one side than the separator (123) without separate cutting.
[0069] As the second active material, the cathode active material, a compound capable of reversible intercalation and deintercalation of lithium (a lithated intercalation compound) may be used. Specifically, one or more composite oxides of lithium and a metal selected from cobalt, manganese, nickel, and combinations thereof may be used.
[0070] The above composite oxide may be a lithium transition metal composite oxide, and specific examples include a lithium nickel-based oxide, a lithium cobalt-based oxide, a lithium manganese-based oxide, a lithium iron phosphate-based compound, a cobalt-free nickel-manganese-based oxide, or a combination thereof.
[0071] As an example, a compound represented by any one of the following chemical formulas may be used. Li a A 1-b X b O 2-c D c (0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.05); Li a Mn 2-b X b O 4-c D c (0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.05); Li a Ni 1-b-c Co b X c O 2-α D α (0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.5, 0<α<2); Li a Ni 1-b-c Mn b X c O 2-α D α (0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.5, 0<α<2); Li a Ni b Co c L 1 d G e O2(0.90≤a≤1.8, 0≤b≤0.9, 0≤c≤0.5, 0≤d≤0.5, 0≤e≤0.1); Li a NiG b O2(0.90≤a≤1.8, 0.001≤b≤0.1); Li a CoG b O2(0.90≤a≤1.8, 0.001≤b≤0.1); Li a Mn 1-b G bO2(0.90≤a≤1.8, 0.001≤b≤0.1); Li a Mn2G b O4(0.90≤a≤1.8, 0.001≤b≤0.1); Li a Mn 1-g G g PO4(0.90≤a≤1.8, 0≤g≤0.5); Li (3-f) Fe2(PO4)3(0≤f≤2); Li a FePO4(0.90≤a≤1.8).
[0072] In the above 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; L 1 is Mn, Al, or a combination thereof.
[0073] 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 may include a positive electrode active material and may further include a binder and / or a conductive material.
[0074] The content of the positive active material is 90% to 99.5% by weight with respect to 100% by weight of the positive active material layer, and the content of the binder and the conductive material may each be 0.5% to 5% by weight with respect to 100% by weight of the positive active material layer.
[0075] Al may be used as the current collector mentioned above, but is not limited thereto.
[0076] In some examples, electrode leads may be included so that the first electrode tab (124) and the second electrode tab (125) are electrically connected to the outside. The first electrode tab (124) and the second electrode tab (125) are welded to the electrode leads of an external terminal to be electrically connected to the outside.
[0077] A separator (123) is interposed between the first electrode plate (121) and the second electrode plate (122) to prevent an electrical short circuit between the first electrode plate (121) and the second electrode plate (122).
[0078] Depending on the type of lithium secondary battery, a separator (123) may be present between the positive and negative electrodes. As such a separator (123), polyethylene, polypropylene, polyvinylidene fluoride, or a multilayer film of two or more layers thereof may be used.
[0079] The separator (123) may include a porous substrate and a coating layer comprising an organic material, an inorganic material, or a combination thereof located on one or both sides of the porous substrate.
[0080] The above organic material may include a polyvinylidene fluoride-based polymer or a (meth)acrylic-based polymer.
[0081] The above inorganic material may include inorganic particles selected from Al2O3, SiO2, TiO2, SnO2, CeO2, MgO, NiO, CaO, GaO, ZnO, ZrO2, Y2O3, SrTiO3, BaTiO3, Mg(OH)2, boehmite, and combinations thereof, but is not limited thereto.
[0082] The above organic and inorganic materials may exist mixed in a single coating layer, or may exist in a stacked form with a coating layer containing organic materials and a coating layer containing inorganic materials.
[0083] FIG. 4 is a longitudinal cross-sectional view illustrating an electrode assembly of a secondary battery according to an embodiment of the present invention. FIG. 5 is a front view illustrating the state before winding of an electrode assembly located at the leading end turn, in which one reinforcing member of a secondary battery according to an embodiment of the present invention is positioned. Here, for the understanding of the present invention, the electrode assembly (120) is illustrated in an exaggerated manner. For example, the first electrode plate (121), the separator (123), and the second electrode plate (122) are in close contact with each other, but for convenience of understanding, they are illustrated as being spaced apart from each other. The first electrode tab (124) and the four vertical dotted lines on both sides in FIG. 5 may indicate the turn position when the electrode assembly (120) is wound.
[0084] Referring to FIG. 4, the electrode assembly (120) may include a first electrode plate (121), a separator (123) positioned on the upper and lower surfaces of the first electrode plate (121), respectively, and a second electrode plate (122) positioned on one of the separators (123). In some examples, the electrode assembly (120) may be approximately cylindrical in shape by winding the first electrode plate (121), the separator (123), and the second electrode plate (122) in a stacked manner. In some examples, the part where the winding begins (approximately the central area of the wound electrode assembly (120)) may be defined as the winding end. In some examples, the part where the winding ends (approximately the outermost area of the wound electrode assembly (120)) may be defined as the winding end.
[0085] In some examples, the first electrode tab (124) may extend downward from the first electrode plate (121) and be electrically / thermally coupled to the bottom portion (111) of the cylindrical can (110). In some examples, the second electrode tab (125) may extend upward from the second electrode plate (122) and be electrically / thermally coupled to the cap assembly (140) (see FIG. 2 and FIG. 3).
[0086] In some examples, when the first electrode tab (124) and the second electrode tab (125) are formed in the center with respect to the longitudinal direction of the first electrode plate (121) and the second electrode plate (122), the first electrode tab (124) and the second electrode tab (125) may be referred to as middle tabs. For example, the first electrode tab (124) and the second electrode tab (125) that are middle tabs may be located between the winding front end and the winding end.
[0087] Referring to FIG. 4, the secondary battery (100) may further include an insulating member (150) and a reinforcing member (160). In some examples, the insulating member (150) may be attached to the first electrode plate (121) to cover at least a portion of the first electrode tab (124) provided on the first electrode plate (121).
[0088] In some examples, the reinforcing member (160) may be provided within a certain range along the same line from the winding center of the electrode assembly (120) to the outermost edge, with respect to the first electrode tab (124). For example, referring to FIG. 4, the reinforcing member (160) may be positioned at a distance of one full turn in the direction of the winding center of the electrode assembly (120) with respect to the first electrode tab (124). However, it is not limited thereto, and the reinforcing member (160) may be positioned at a distance of one full turn or two full turns in the direction of the winding center of the electrode assembly (120) with respect to the first electrode tab (124). Additionally, the reinforcing member (160) may be positioned at a distance of one full turn or two full turns in the direction of the winding end of the electrode assembly (120) with respect to the first electrode tab (124). In some examples, for convenience of explanation, the first electrode plate (121) and the first electrode tab (124) are described as being the basis, but the insulating member (150) and the reinforcing member (160) may also be applied to the second electrode plate (122) and the second electrode tab (125).
[0089] Referring to FIG. 5, the first electrode plate (121) may include a conductive first substrate (or may be referred to as a current collector, current collector, etc.) (1211), a first coating portion (1214) provided by coating a first active material on the first substrate (1211), and a first uncoated portion (1216) on the first substrate (1211) in which the first active material is not coated. That is, the first uncoated portion (1216) may be a part of the first substrate (1211). In some examples, the first uncoated portion (1216) may be formed approximately in the center of the first substrate (1211). That is, in some examples, the first coating portion (1214) of the first substrate (1211) may be composed of two divided portions. In some examples, the two divided portions may be spaced apart from each other, and the first uncoated portion (1216) may be provided between them. In some examples, the first coating portion (1214) may be formed on both sides of the first substrate (1211) with respect to the first uncoated portion (1216). A first electrode tab (124) that is approximately flat may be provided on the first uncoated portion (1216). The first electrode tab (124) may be provided on one side of the first substrate (1211). In FIG. 5, the length of the first electrode plate (121) is depicted as being reduced from the actual length, and the first electrode tab (124) may be located approximately in the middle of the entire length in the longitudinal direction (horizontal direction with respect to FIG. 5) of the first electrode plate (121).
[0090] In some examples, the first electrode tab (124) may be provided to protrude upward from approximately the middle portion with respect to the width direction (vertical direction with respect to FIG. 5) of the first electrode plate (121). In some examples, the first electrode tab (124) may be provided to protrude upward from the bottom boundary portion of the first electrode plate (121) with respect to the width direction of the first electrode plate (121). That is, the length of the first electrode tab (124) may be shorter or longer than that shown in FIG. 5.
[0091] In some examples, the first electrode tab (124) may be attached to the first bare portion (1216) and then attached to an insulating member (150). One end of the first electrode tab (124) is electrically connected to the first bare portion (1216), and the other end may protrude and extend outward. The insulating member (150) may be attached to the first bare portion (1216) while wrapping the first electrode tab (124). In some examples, the insulating member (150) may also be attached to the opposite side of the surface to which the first electrode tab (124) is attached. Here, the sum of the thickness of the first electrode tab (124) and the thickness of the insulating member (150) may be formed to be equal to or thinner than the thickness of the first coating portion (1214).
[0092] In some examples, the insulating member (150) may be attached within the first bare portion (1216). The insulating member (150) may be provided to be larger than the width of the first bare portion (1216) so as to be attached to cover the entire first bare portion (1216). In some examples, the insulating member (150) may be composed of an adhesive layer and an insulating layer. The adhesive layer helps the tape adhere well to the electrode tab, and the insulating layer can provide electrical insulation. The insulating member (150) may be formed from an insulating tape comprising, for example, polyethylene terephthalate (PET), polyphenylene sulfide (PS), polyimide (PI), or polypropylene (PP). The insulating member (150) can prevent the first electrode tab (124) and / or the first current collector plate (1215) from being short-circuited with the second electrode plate (122).
[0093] Meanwhile, the charging and discharging of a secondary battery involves volume expansion of the electrode plates constituting the battery. This expansion of the electrode plates occurs in all directions due to the reaction of the active material with lithium, which induces cracks in the metal thin film substrate. At this time, the portion of the substrate in contact with the tab welded to the substrate becomes vulnerable due to the step difference, causing cracks to form around the tab. To suppress crack formation, it is common practice to attach tape around the tab on the electrode plate substrate, and a general approach involves modifying the mechanical properties of the tape, such as tensile strength and elongation. However, in the case of high-content silicon electrode plates, where the amount of expansion has increased rapidly due to the trend toward higher capacity secondary batteries, the application of conventional methods may have limitations.
[0094] Referring to FIG. 5, the part where winding begins on the first electrode plate (121) can be defined as the leading end (P1), and the part where winding ends can be defined as the ending end (P2). The reinforcing member (160) may be provided at a position one turn in the leading end direction (P1) with respect to the first electrode tab (124). In some examples, the reinforcing member (160) may be positioned at a distance of one full turn in the winding center direction of the electrode assembly (120) with respect to the first electrode tab (124).
[0095] In some examples, the reinforcing member (160) may be provided at a position in the longitudinal direction (P2) relative to the first electrode tab (124). The reinforcing member (160) may be positioned at a distance equivalent to one full rotation in the winding longitudinal direction of the electrode assembly (120) relative to the first electrode tab (124).
[0096] The reinforcing member (160) may be attached in the width direction (up and down direction based on FIG. 5) of the first electrode plate (121). In some examples, the reinforcing member (160) may be attached with a portion protruding in the width direction of the first electrode plate (121). The reinforcing member (160) may protrude with equal lengths in the upper and lower directions in the width direction of the first electrode plate (121). In some examples, the reinforcing member (160) may protrude with different lengths in the upper and lower directions in the width direction of the first electrode plate (121). For example, the reinforcing member (160) of the first electrode plate (121) may be attached so as to protrude further in the upward direction.
[0097] In some examples, the width (d2) of the reinforcing member (160) in the longitudinal direction (left-right direction with respect to FIG. 5) of the first electrode plate (121) may be equal to or greater than the width (w1) of the first electrode tab (124). In some examples, the width (d2) of the reinforcing member (160) may be equal to or greater than the width (d1) of the insulating member (150). In some examples, the width (d2) of the reinforcing member (160) may be equal to or less than the width (w2) of the first non-reinforcing portion (1216). In some examples, the width (d2) of the reinforcing member (160) may be included between the width (w1) of the first electrode tab (124) and the width (w2) of the first non-reinforcing portion (1216).
[0098] If the width (d2) of the reinforcing member (160) is greater than the width (w1) of the first electrode tab (124), the reinforcing member (160) covers a wider area than the first electrode tab (124), thereby protecting a wider area from cracks or damage around the first electrode tab (124). If the width (d2) of the reinforcing member (160) is smaller than the width (w1) of the first unoccupied portion (1216), the reinforcing member (160) can provide a concentrated protective effect on the electrode assembly portions at the 1st and 2nd turn positions of the first electrode tab (124) within the first unoccupied portion (1216), thereby minimizing the impact on adjacent cell components and minimizing the impact on the internal space of the secondary battery.
[0099] In some examples, the second electrode plate (122) may include a second substrate made of a metal thin plate with excellent conductivity, for example, aluminum foil or mesh, a second coating portion coated on the second substrate, and a second uncoated portion on the second substrate in which the second active material is not coated. In some examples, the second electrode plate (122) and the second electrode tab (125) may be implemented similarly to the first electrode plate (121) and the first electrode tab (124) described above, so a detailed description may be omitted.
[0100] In some examples, the reinforcing member (160) is provided on the first electrode plate (121) or the second electrode plate (122), and may be provided on both the first electrode plate (121) and the second electrode plate (122).
[0101] In some examples, the secondary battery (100) may include a reinforcing member (160) on the first electrode plate (121) to improve cracks around the first electrode tab (124) located between the winding center and the outermost edge. The reinforcing member (160) may be provided on the leading side (P1) or the trailing side (P2) with respect to the first electrode tab (124). Referring to FIG. 5, the reinforcing member (160) may be located on the same line as the electrode assembly (120) with respect to the first electrode tab (124). For example, at least one reinforcing member (160) may be located on the line connecting the winding center and the first electrode tab (124) (see FIG. 4).
[0102] In some examples, the reinforcing member (160) may be provided at the 1st and 2nd turn positions relative to the first electrode tab (124). In some examples, "1st turn" may mean the length in which the first electrode plate (121) completely wraps around the electrode assembly (120). That is, at least a portion of the reinforcing member (160) located at the 1st or 2nd turn of the first electrode tab (124) may be located on a straight line from the winding center relative to the first electrode tab (124) to the outermost edge.
[0103] FIG. 6 is a front view illustrating the state before winding a reinforcing member formed of a plurality of units in a secondary battery according to one embodiment of the present invention onto an electrode assembly located at the leading edge turn.
[0104] Referring to FIG. 6, the reinforcing member (160) may include a plurality of units. In some examples, the reinforcing member (160) may have a plurality of reinforcing members (160a, 160b, 160c) located in one turn of the first electrode tab (124). The plurality of reinforcing members (160a, 160b, 160c) may be arranged with spacing. The plurality of reinforcing members (160a, 160b, 160c) may be spaced apart at a certain interval so that each unit may be composed of the same area, shape, thickness, etc., but is not limited thereto and may be composed of different areas, shapes, thicknesses, etc.
[0105] A structure in which reinforcing members (160) are divided into multiple units and arranged such that each unit is arranged independently allows the overall structure to be more flexible. This enables each unit to move independently when the reinforcing members (160) bend or deform, thereby improving overall durability and adaptability. Additionally, by combining units of various sizes or shapes, a more customized design tailored to a specific application may be possible. For example, if more reinforcement is required in a specific area, the thickness of the unit at that point can be made greater than the thickness of other units, or the units can be concentrated at that point.
[0106] In some examples, a reinforcing member (160) may be attached to the first coating portion (11214) of the first electrode plate (121). As the reinforcing member (160) is attached, the first coating portion (1214) becomes an unreacted portion, thereby minimizing the expansion of the tab portion electrode plate and suppressing the formation of cracks by the first electrode tab (124).
[0107] In some examples, the reinforcing member (160) may include at least one of a polystyrene-based (PS, polystyrene), a polyester-based (PET, polyester), a polyimide-based (PI, polyimide) and a polyaramid-based material.
[0108] FIG. 7 is a front view illustrating the state before winding of an electrode assembly in which two reinforcing members are located in turn 1 of a secondary battery according to an embodiment of the present invention. FIG. 8 is a front view illustrating the state before winding of an electrode assembly in which three reinforcing members are located in turns 1 and 2 of a secondary battery according to an embodiment of the present invention. FIG. 9 is a front view illustrating the state before winding of an electrode assembly in which four reinforcing members are located in turns 1 and 2 of a secondary battery according to an embodiment of the present invention.
[0109] Referring to FIG. 7, the reinforcing member (260) may include a first reinforcing member (261) and a second reinforcing member (262). The first reinforcing member (261) may be provided at a position one turn in the leading direction relative to the first electrode tab (124). The second reinforcing member (262) may be provided at a position one turn in the trailing direction relative to the first electrode tab (124). The first reinforcing member (261) and the second reinforcing member (262) may be made of the same material or different materials.
[0110] In some examples, the first reinforcing member (261) and the second reinforcing member (262) may be attached in the width direction of the first electrode plate (121). The first reinforcing member (261) and the second reinforcing member (262) may be attached with a portion protruding in the width direction of the first electrode plate (121). The first reinforcing member (261) and the second reinforcing member (262) may protrude with equal lengths in the upper and lower directions in the width direction of the first electrode plate (121). In some examples, the first reinforcing member (261) and the second reinforcing member (262) may protrude with different lengths in the upper and lower directions in the width direction of the first electrode plate (121). The widths (d2, d3) of the first reinforcing member (261) and the second reinforcing member (262) may each be equal to or greater than the width (w1) of the first electrode tab (124). In some examples, the widths (d2, d3) of the first reinforcing member (261) and the second reinforcing member (262) may each be equal to or greater than the width (d1) of the insulating member (150). In some examples, the widths (d2, d3) of the first reinforcing member (261) and the second reinforcing member (262) may each be equal to or smaller than the width (w2) of the first non-reinforcing member (1216). In some examples, the widths (d2, d3) of the first reinforcing member (261) and the second reinforcing member (262) may each be included between the width (w1) of the first electrode tab (124) and the width (w2) of the first non-reinforcing member (1216).
[0111] Referring to FIG. 8, the reinforcing member (360) may include a first reinforcing member (361), a second reinforcing member (362), and a third reinforcing member (363). The first reinforcing member (361) and the second reinforcing member (362) may be provided at a position one turn and two turns in the leading direction relative to the first electrode tab (124). The third reinforcing member (363) may be provided at a position one turn in the trailing direction relative to the first electrode tab (124). The first reinforcing member (361), the second reinforcing member (362), and the third reinforcing member (363) may be made of the same material or different materials.
[0112] In some examples, the first reinforcing member (361), the second reinforcing member (362), and the third reinforcing member (363) may be attached in the width direction of the first electrode plate (121). The first reinforcing member (361), the second reinforcing member (362), and the third reinforcing member (363) may be attached with a portion protruding in the width direction of the first electrode plate (121). The first reinforcing member (361), the second reinforcing member (362), and the third reinforcing member (363) may protrude with equal lengths in the upper and lower directions in the width direction of the first electrode plate (121). In some examples, the first reinforcing member (361), the second reinforcing member (362), and the third reinforcing member (363) may protrude with different lengths in the upper and lower directions in the width direction of the first electrode plate (121). The widths (d2, d) of the first reinforcing member (361), the second reinforcing member (362), and the third reinforcing member (363) 3, d4) may each be equal to or greater than the width (w1) of the first electrode tab (124). In some examples, the widths (d2, d) of the first reinforcing member (361), the second reinforcing member (362), and the third reinforcing member (363) are 3, d4) may be equal to or greater than the width (d1) of the insulating member (150). In some examples, the widths (d2, d) of the first reinforcing member (361), the second reinforcing member (362), and the third reinforcing member (363) are 3, d4) may each be equal to or smaller than the width (w2) of the first non-reinforcing member (1216). In some examples, the widths (d2, d) of the first reinforcing member (361), the second reinforcing member (362), and the third reinforcing member (363) 3, d4) may each be included between the width (w1) of the first electrode tab (124) and the width (w2) of the first non-reinforcing portion (1216). In some examples, the second reinforcing member (362) may be omitted.
[0113] Referring to FIG. 9, the reinforcing member (460) may include a first reinforcing member (461), a second reinforcing member (462), a third reinforcing member (463), and a fourth reinforcing member (464). The first reinforcing member (461) and the third reinforcing member (463) may be provided at positions 1 and 2 turns in the leading direction relative to the first electrode tab (124). The second reinforcing member (462) and the fourth reinforcing member (464) may be provided at positions 1 and 2 turns in the trailing direction relative to the first electrode tab (124). The first reinforcing member (461), the second reinforcing member (462), the third reinforcing member (463), and the fourth reinforcing member (464) may be made of the same material or different materials.
[0114] In some examples, the first reinforcing member (461), the second reinforcing member (462), the third reinforcing member (463), and the fourth reinforcing member (464) may be attached in the width direction of the first electrode plate (121). The first reinforcing member (461), the second reinforcing member (462), the third reinforcing member (463), and the fourth reinforcing member (464) may be attached with a portion protruding in the width direction of the first electrode plate (121). The first reinforcing member (461), the second reinforcing member (462), the third reinforcing member (463), and the fourth reinforcing member (464) may protrude with equal lengths in the upper and lower directions in the width direction of the first electrode plate (121). In some examples, the first reinforcing member (461), the second reinforcing member (462), the third reinforcing member (463), and the fourth reinforcing member (464) may protrude in the width direction of the first electrode plate (121) with different lengths at the top and bottom. The widths (d2, d) of the first reinforcing member (461), the second reinforcing member (462), the third reinforcing member (463), and the fourth reinforcing member (464) 3, d 4, d5) may each be equal to or greater than the width (w1) of the first electrode tab (124). In some examples, the widths (d2, d) of the first reinforcing member (461), the second reinforcing member (462), the third reinforcing member (463), and the fourth reinforcing member (464) are 3, d 4,d5) may be equal to or greater than the width (d1) of each insulating member (150). In some examples, the widths (d2, d) of the first reinforcing member (461), the second reinforcing member (462), the third reinforcing member (463), and the fourth reinforcing member (464) are 3, d 4, d5) may each be equal to or smaller than the width (w2) of the first non-reinforcing member (1216). In some examples, the widths (d2, d) of the first reinforcing member (461), the second reinforcing member (462), the third reinforcing member (463), and the fourth reinforcing member (464) are 3, d 4, d5) may each be included between the width (w1) of the first electrode tab (124) and the width (w2) of the first unwound portion (1216). FIG. 16 is a cross-sectional view illustrating the state of the first electrode plate of the electrode assembly before winding in a secondary battery according to one embodiment of the present invention.
[0115] FIG. 10 is a cross-sectional view illustrating the state before winding of the first electrode plate of an electrode assembly with a reinforcing member attached, according to one embodiment of the present invention. The first electrode tab (124) and the four vertical dotted lines on both sides of FIG. 10 may indicate the turn position when the electrode assembly (120) is wound.
[0116] Referring to FIG. 10, the first electrode plate (121) may include a conductive first substrate (1211) having a first surface (1212) and a second surface (1213), a first coating portion (1214, 1215) provided with a first active material coated on the first surface (1212) and the second surface (1213) of the first substrate (1211), and a first uncoated portion (1216, 1217) in which the first active material is not coated on the first surface (1212) and the second surface (1213) of the first substrate (1211).
[0117] In some examples, the length of the first leg portion (1217) of the second side (1213) may be the same as or different from the length of the first leg portion (1216) of the first side (1212).
[0118] In some examples, the first electrode tab (124) may be located in the first non-removable portion (1217).
[0119] In some examples, the reinforcing member (160) may be provided on both sides of the first substrate (1211). The reinforcing member (160) may be provided on the first surface (1212) and the second surface (1213) at a 1-turn or 2-turn position on the leading side or the trailing side with respect to the first electrode tab (124). In some examples, the reinforcing member (160) may be attached to both sides of the first coating portion (1214, 1215) of the first substrate (1211).
[0120] When a first electrode plate (121) having a middle tab structure is wound to form an electrode assembly (120), the first electrode tab (124) protrudes from the middle portion between the center of the winding of the electrode assembly (120) and the outermost edge. When a laminate of the first electrode plate (121), separator (130), second electrode plate (122), and separator (130) is wound from the leading edge (P1) to form an electrode assembly (120), the reinforcing member (160) may be located on the same line as the first electrode tab (124). In some examples, one to four reinforcing members (160) may be provided at the same radius as the first electrode tab (124), at the leading edge or the end edge, at the 1st or 2nd turn position relative to the first electrode tab (124). If the number of reinforcing members (160) exceeds four, the many additional members may affect adjacent cell components and reduce space efficiency within the battery. By providing one to four reinforcing members (140), the use of unnecessary materials can be reduced and weight reduction can be achieved.
[0121] FIG. 11 is a cross-sectional view illustrating the state before winding of the first electrode plate of an electrode assembly coated with a reinforcing member in a secondary battery according to one embodiment of the present invention.
[0122] Referring to FIG. 11, in some examples, the reinforcing member (560) may not form a first active material layer on the portion of the first substrate (1211) to which the reinforcing member (560) is to be attached. That is, the first active material layer may be intermittently coated to form a first coated portion (1214, 1215), and the reinforcing member (560) may be added to a second uncoated portion (1218, 1219) where the first active material is not coated. Thus, the first active material layer may be located on both sides of the reinforcing member (560). In some examples, the first coated portion (1214, 1215) may be located in four spaced-apart portions. In some examples, the first electrode plate (121) may include a first uncoated portion (1216, 1217) and a second uncoated portion (1218, 1219). In some examples, the first electrode tab (124) may be provided in the first non-removable portion (1217).
[0123] When a laminate of the first electrode plate (121), separator (123), second electrode plate (122), and separator (123) is wound from the leading edge to form an electrode assembly (120), the reinforcing member (560) may be positioned in alignment with the first electrode tab (124). In some examples, one to four reinforcing members (560) may be provided at the same radius as the first electrode tab (124), at the leading edge or the end edge, at the 1st or 2nd turn position relative to the first electrode tab (124).
[0124] The reinforcing member (560) may be coated on both sides of the first electrode plate (121). The width of the reinforcing member (560) may be formed to be equal to or wider than the width of the insulating member (150). The width of the reinforcing member (560) may be formed to be equal to or smaller than the width of the second uninsulated portion (1218, 1219).
[0125] In some examples, the reinforcing member (560) may include an insulating material such as a ceramic material. For example, the ceramic material may include Al2O3, SiO2, TiO2, SnO2, CeO2, MgO, NiO, CaO, ZnO, ZrO2, Y2O3, SrTiO3, BaTiO3, Mg(OH)2, or a combination thereof. The ceramic material may include an inorganic compound to improve heat resistance, thereby preventing the separator (123) from shrinking or deforming rapidly due to a rise in temperature. The thickness of the reinforcing member (560) (in the vertical direction with respect to FIG. 11) may be formed to be equal to the thickness of the active material layer of the first coating portion (1214, 1215). Accordingly, when the electrode assembly (120) is formed, the second electrode plate (122) and the first electrode plate (121) are wound in a flat shape with the separator (123) in between, so the problem of lithium precipitation due to the thickness difference between the second electrode plate (122) and the first electrode plate (121) can be resolved. In addition, the coating method of the reinforcing member (560) may use conventional coating methods known in the art, and various methods such as dip coating, spin coat coating, roll coating, Meyer bar coating, comma coating, die coating, gravure coating, screen printing, offset printing, brush painting, spraying, or a combination thereof may be used. In this way, the electrode assembly (120) according to the present invention can improve safety by ensuring gap uniformity and flatness between electrode plates by forming a reinforcing member (560) having the same thickness as the first active material layer of the first coating portion (1214, 1215).
[0126] FIG. 12 is a schematic diagram simply illustrating a smartphone equipped with a secondary battery according to an embodiment of the present invention. As shown in FIG. 12, the secondary battery pack (1) according to the aforementioned embodiment of the present invention may be a small battery mounted in a small portable device such as a smartphone (1000). In this case, since the exemplary secondary battery pack (1) has a structure that can increase the capacity of the secondary battery pack (1) by slimming down its internal structure, the aforementioned secondary battery pack (1) may be a battery suitable for application in a small portable device. Meanwhile, in this specification, secondary battery, battery, and cell have the same meaning, and only their descriptions are different for convenience of explanation.
[0127] In some examples, the secondary battery pack (1) may be made of a single cell, but may be used to manufacture a battery pack including multiple cells or to manufacture a larger battery pack by increasing the size of the battery cells.
[0128] FIGS. 13a and FIGS. 13b are perspective views illustrating an exemplary battery pack (30). The battery pack (30) may include a plurality of battery modules (20) and a housing (31) for accommodating the plurality of battery modules (20). For example, the housing (31) may include first and second housings (31-1, 31-2) that are coupled in a direction facing each other with the plurality of battery modules (20) interposed therebetween. The plurality of battery modules (20) may be electrically connected to each other using a bus bar (25-1), and the plurality of battery modules (20) may be electrically connected to each other in a series / parallel or mixed series / parallel manner to obtain the required electrical output.
[0129] FIGS. 14a and FIGS. 14b are a perspective view and a side view illustrating an exemplary vehicle body (40) and a vehicle body part. In FIG. 14a, the battery pack (30) may include a battery pack cover (30-1) which is part of the vehicle underbody (41) and a pack frame (30-2) which is positioned below the vehicle underbody (41). In some examples, the battery pack cover (30-1) may correspond to a first housing (31-1), and the pack frame (30-2) may correspond to a second housing (31-2). The battery pack cover (30-1) and the pack frame (30-2) may be structures formed integrally with the vehicle floor portion (42). The vehicle underbody (41) separates the interior and exterior of the vehicle, and the pack frame (30-2) may be positioned outside the vehicle.
[0130] As illustrated in FIG. 14b, the vehicle (50) may be formed by combining additional parts, such as a hood (51) at the front of the vehicle and fenders (52) located at the front and rear of the vehicle, respectively, with the vehicle body parts. The vehicle (50) includes a battery pack (30) comprising a battery pack cover (30-1) and a pack frame (30-2), and the battery pack (30) may be combined with the vehicle body parts.
[0131] 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 spirit of the present invention and the equivalent scope of the claims described below by those skilled in the art to which the present invention belongs. Explanation of the symbols
[0132] 1: Secondary battery pack 100: Secondary battery 110: Can 111: Bottom part 112: Sidewall 113: Bidding Department 114: Creaming Department 120: Electrode assembly 121: First electrode plate 1211: First entry 1212, 1213: Pages 1 and 2 1214, 1215: 1st coating section 1216, 1217: First Department of Non-Duti 1218, 1219: Second Department of Indefinitely 122: Second electrode plate 123: Separator 124: First electrode tab 125: Second electrode tab 126: First insulating plate 126a, 126b: 1st and 2nd holes 127: Second insulating plate 127a, 127b: 1st and 2nd holes 130: Center pin 140: Cap assembly 141: Cap Up 141a: Through hole 142: Safety vent 143: Connecting ring 144: Cap Down 144a: Through hole 145: Insulating gasket 150: Insulating member 160, 260, 360, 460, 560: Reinforcing members 20: Battery Module 25: Bus Bar 30: Battery pack 30-1: Pack Cover 30-2: Pack Frame 31: Housing 31-1: 1st Housing 31-2: Second Housing 40: Chassis 41: Underbody 42: Bottom part 50: Vehicle 51: Hood 52: Fender 1000: Smartphone
Claims
Claim 1 A secondary battery comprising: a case; an electrode assembly that is housed in the case and includes a first electrode plate, a separator positioned on the first electrode plate, and a second electrode plate positioned on the separator, wherein the first electrode plate, the separator, and the second electrode plate are stacked and wound; a cap assembly that seals the case; an insulating member attached to the first electrode plate to cover at least a portion of a first electrode tab attached to the first electrode plate; and at least one reinforcing member provided in a certain range along the same line from the winding center of the electrode assembly to the outermost edge with respect to the first electrode tab. Claim 2 A secondary battery according to claim 1, wherein the first electrode tab is located between the winding center and the outermost edge of the electrode assembly. Claim 3 A secondary battery according to claim 1, wherein the reinforcing member is positioned spaced apart by a distance of one or two turns in the direction of the winding center of the electrode assembly relative to the first electrode tab. Claim 4 A secondary battery according to claim 1, wherein the reinforcing member is positioned spaced apart by a distance of one or two turns in the winding end direction of the electrode assembly relative to the first electrode tab. Claim 5 A secondary battery according to claim 1, wherein the width of the reinforcing member in the longitudinal direction of the first electrode plate is equal to or greater than the width of the first electrode tab. Claim 6 A secondary battery according to claim 1, wherein the width of the reinforcing member in the longitudinal direction of the first electrode plate is equal to or greater than the width of the insulating member. Claim 7 A secondary battery according to claim 1, wherein the reinforcing member protrudes upward or downward in the width direction of the first electrode plate, and the length of the reinforcing member protruding upward or downward in the width direction of the first electrode plate is the same or different. Claim 8 A secondary battery according to claim 1, wherein the material of the reinforcing member is at least one of polystyrene-based (PS, polystyrene), polyester-based (PET, polyester), polyimide-based (PI, polyimide) and polyaramid-based. Claim 9 A secondary battery according to claim 1, wherein the first electrode plate comprises a first substrate having an inner surface and an outer surface, a first coating portion having a first active material coated on the inner surface and the outer surface of the first substrate respectively, and a first non-coated portion having no first active material coated on the inner surface and the outer surface of the first substrate respectively, and the first non-coated portion is located between the first coating portions. Claim 10 A secondary battery according to claim 9, wherein the first electrode tab is provided on the inner or outer surface of the first uncoated portion, and the reinforcing member is provided on the inner and outer surfaces of the first coating portion. Claim 11 A secondary battery according to claim 9, wherein the first electrode tab is coupled to the inner or outer surface of the first non-reinforced portion, and further comprises a second non-reinforced portion provided in a certain range on the same line from the winding center of the wound electrode assembly to the outermost edge based on the first electrode tab. Claim 12 In claim 11, the reinforcing member is a secondary battery provided on the inner and outer surfaces of the second non-reinforcing portion. Claim 13 A secondary battery according to claim 11, wherein the width of the reinforcing member in the longitudinal direction of the first electrode plate is equal to or greater than the width of the second unsupported portion. Claim 14 A secondary battery according to claim 11, wherein the thickness of the reinforcing member is the same as the thickness of the first active material of the first coating portion. Claim 15 A secondary battery according to claim 1, wherein two to four reinforcing members are provided on the same line with respect to the first electrode tab, and the reinforcing members are positioned spaced apart by a distance of one or two full turns in the winding center direction of the electrode assembly with respect to the first electrode tab, and spaced apart by a distance of one or two full turns in the winding end direction of the electrode assembly with respect to the first electrode tab. Claim 16 In claim 15, a secondary battery in which the widths of the plurality of reinforcing members in the longitudinal direction of the first electrode plate are the same or different from each other. Claim 17 In claim 15, a secondary battery in which the upper or lower protrusion lengths of the plurality of reinforcing members in the width direction of the first electrode plate are the same or different. Claim 18 A secondary battery according to claim 1, wherein the reinforcing member comprises a plurality of reinforcing member units arranged with spacing. Claim 19 In claim 18, a secondary battery in which the thicknesses of the plurality of reinforcing member units are the same or different. Claim 20 A secondary battery according to claim 1, further comprising: an insulating member attached to the second electrode plate to cover at least a portion of the second electrode tab attached to the second electrode plate; and at least one reinforcing member provided in a certain range along the same line from the winding center of the wound electrode assembly to the outermost edge with respect to the second electrode tab.